From 2f981978575688086c5618341c0d438314c87666 Mon Sep 17 00:00:00 2001 From: Brad Fitzpatrick Date: Tue, 11 Feb 2025 07:26:49 -0800 Subject: [PATCH] tempfork/sshtest/ssh: add fork of golang.org/x/crypto/ssh for testing only This fork golang.org/x/crypto/ssh (at upstream x/crypto git rev e47973b1c1) into tailscale.com/tempfork/sshtest/ssh so we can hack up the client in weird ways to simulate other SSH clients seen in the wild. Two changes were made to the files when they were copied from x/crypto: * internal/poly1305 imports were replaced by the non-internal version; no code changes otherwise. It didn't need the internal one. * all decode-with-passphrase funcs were deleted, to avoid using the internal package x/crypto/ssh/internal/bcrypt_pbkdf Then the tests passed. Updates #14969 Change-Id: Ibf1abebfe608c75fef4da0255314f65e54ce5077 Signed-off-by: Brad Fitzpatrick --- ssh/tailssh/tailssh_test.go | 3 + tempfork/sshtest/README.md | 9 + tempfork/sshtest/ssh/benchmark_test.go | 127 ++ tempfork/sshtest/ssh/buffer.go | 97 + tempfork/sshtest/ssh/buffer_test.go | 87 + tempfork/sshtest/ssh/certs.go | 611 +++++++ tempfork/sshtest/ssh/certs_test.go | 406 ++++ tempfork/sshtest/ssh/channel.go | 645 +++++++ tempfork/sshtest/ssh/cipher.go | 789 ++++++++ tempfork/sshtest/ssh/cipher_test.go | 231 +++ tempfork/sshtest/ssh/client.go | 282 +++ tempfork/sshtest/ssh/client_auth.go | 796 ++++++++ tempfork/sshtest/ssh/client_auth_test.go | 1384 ++++++++++++++ tempfork/sshtest/ssh/client_test.go | 367 ++++ tempfork/sshtest/ssh/common.go | 476 +++++ tempfork/sshtest/ssh/common_test.go | 176 ++ tempfork/sshtest/ssh/connection.go | 143 ++ tempfork/sshtest/ssh/doc.go | 23 + tempfork/sshtest/ssh/example_test.go | 400 ++++ tempfork/sshtest/ssh/handshake.go | 816 +++++++++ tempfork/sshtest/ssh/handshake_test.go | 1021 +++++++++++ tempfork/sshtest/ssh/kex.go | 786 ++++++++ tempfork/sshtest/ssh/kex_test.go | 106 ++ tempfork/sshtest/ssh/keys.go | 1626 +++++++++++++++++ tempfork/sshtest/ssh/keys_test.go | 724 ++++++++ tempfork/sshtest/ssh/mac.go | 68 + tempfork/sshtest/ssh/mempipe_test.go | 124 ++ tempfork/sshtest/ssh/messages.go | 891 +++++++++ tempfork/sshtest/ssh/messages_test.go | 288 +++ tempfork/sshtest/ssh/mux.go | 357 ++++ tempfork/sshtest/ssh/mux_test.go | 839 +++++++++ tempfork/sshtest/ssh/server.go | 933 ++++++++++ .../sshtest/ssh/server_multi_auth_test.go | 412 +++++ tempfork/sshtest/ssh/server_test.go | 478 +++++ tempfork/sshtest/ssh/session.go | 647 +++++++ tempfork/sshtest/ssh/session_test.go | 892 +++++++++ tempfork/sshtest/ssh/ssh_gss.go | 139 ++ tempfork/sshtest/ssh/ssh_gss_test.go | 109 ++ tempfork/sshtest/ssh/streamlocal.go | 116 ++ tempfork/sshtest/ssh/tcpip.go | 509 ++++++ tempfork/sshtest/ssh/tcpip_test.go | 53 + tempfork/sshtest/ssh/testdata_test.go | 63 + tempfork/sshtest/ssh/transport.go | 380 ++++ tempfork/sshtest/ssh/transport_test.go | 113 ++ 44 files changed, 19542 insertions(+) create mode 100644 tempfork/sshtest/README.md create mode 100644 tempfork/sshtest/ssh/benchmark_test.go create mode 100644 tempfork/sshtest/ssh/buffer.go create mode 100644 tempfork/sshtest/ssh/buffer_test.go create mode 100644 tempfork/sshtest/ssh/certs.go create mode 100644 tempfork/sshtest/ssh/certs_test.go create mode 100644 tempfork/sshtest/ssh/channel.go create mode 100644 tempfork/sshtest/ssh/cipher.go create mode 100644 tempfork/sshtest/ssh/cipher_test.go create mode 100644 tempfork/sshtest/ssh/client.go create mode 100644 tempfork/sshtest/ssh/client_auth.go create mode 100644 tempfork/sshtest/ssh/client_auth_test.go create mode 100644 tempfork/sshtest/ssh/client_test.go create mode 100644 tempfork/sshtest/ssh/common.go create mode 100644 tempfork/sshtest/ssh/common_test.go create mode 100644 tempfork/sshtest/ssh/connection.go create mode 100644 tempfork/sshtest/ssh/doc.go create mode 100644 tempfork/sshtest/ssh/example_test.go create mode 100644 tempfork/sshtest/ssh/handshake.go create mode 100644 tempfork/sshtest/ssh/handshake_test.go create mode 100644 tempfork/sshtest/ssh/kex.go create mode 100644 tempfork/sshtest/ssh/kex_test.go create mode 100644 tempfork/sshtest/ssh/keys.go create mode 100644 tempfork/sshtest/ssh/keys_test.go create mode 100644 tempfork/sshtest/ssh/mac.go create mode 100644 tempfork/sshtest/ssh/mempipe_test.go create mode 100644 tempfork/sshtest/ssh/messages.go create mode 100644 tempfork/sshtest/ssh/messages_test.go create mode 100644 tempfork/sshtest/ssh/mux.go create mode 100644 tempfork/sshtest/ssh/mux_test.go create mode 100644 tempfork/sshtest/ssh/server.go create mode 100644 tempfork/sshtest/ssh/server_multi_auth_test.go create mode 100644 tempfork/sshtest/ssh/server_test.go create mode 100644 tempfork/sshtest/ssh/session.go create mode 100644 tempfork/sshtest/ssh/session_test.go create mode 100644 tempfork/sshtest/ssh/ssh_gss.go create mode 100644 tempfork/sshtest/ssh/ssh_gss_test.go create mode 100644 tempfork/sshtest/ssh/streamlocal.go create mode 100644 tempfork/sshtest/ssh/tcpip.go create mode 100644 tempfork/sshtest/ssh/tcpip_test.go create mode 100644 tempfork/sshtest/ssh/testdata_test.go create mode 100644 tempfork/sshtest/ssh/transport.go create mode 100644 tempfork/sshtest/ssh/transport_test.go diff --git a/ssh/tailssh/tailssh_test.go b/ssh/tailssh/tailssh_test.go index 207136659..d22dfe443 100644 --- a/ssh/tailssh/tailssh_test.go +++ b/ssh/tailssh/tailssh_test.go @@ -41,6 +41,7 @@ "tailscale.com/sessionrecording" "tailscale.com/tailcfg" "tailscale.com/tempfork/gliderlabs/ssh" + sshtest "tailscale.com/tempfork/sshtest/ssh" "tailscale.com/tsd" "tailscale.com/tstest" "tailscale.com/types/key" @@ -55,6 +56,8 @@ "tailscale.com/wgengine" ) +type _ = sshtest.Client // TODO(bradfitz,percy): sshtest; delete this line + func TestMatchRule(t *testing.T) { someAction := new(tailcfg.SSHAction) tests := []struct { diff --git a/tempfork/sshtest/README.md b/tempfork/sshtest/README.md new file mode 100644 index 000000000..30c74f525 --- /dev/null +++ b/tempfork/sshtest/README.md @@ -0,0 +1,9 @@ +# sshtest + +This contains packages that are forked & locally hacked up for use +in tests. + +Notably, `golang.org/x/crypto/ssh` was copied to +`tailscale.com/tempfork/sshtest/ssh` to permit adding behaviors specific +to testing (for testing Tailscale SSH) that aren't necessarily desirable +to have upstream. diff --git a/tempfork/sshtest/ssh/benchmark_test.go b/tempfork/sshtest/ssh/benchmark_test.go new file mode 100644 index 000000000..b356330b4 --- /dev/null +++ b/tempfork/sshtest/ssh/benchmark_test.go @@ -0,0 +1,127 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "errors" + "fmt" + "io" + "net" + "testing" +) + +type server struct { + *ServerConn + chans <-chan NewChannel +} + +func newServer(c net.Conn, conf *ServerConfig) (*server, error) { + sconn, chans, reqs, err := NewServerConn(c, conf) + if err != nil { + return nil, err + } + go DiscardRequests(reqs) + return &server{sconn, chans}, nil +} + +func (s *server) Accept() (NewChannel, error) { + n, ok := <-s.chans + if !ok { + return nil, io.EOF + } + return n, nil +} + +func sshPipe() (Conn, *server, error) { + c1, c2, err := netPipe() + if err != nil { + return nil, nil, err + } + + clientConf := ClientConfig{ + User: "user", + HostKeyCallback: InsecureIgnoreHostKey(), + } + serverConf := ServerConfig{ + NoClientAuth: true, + } + serverConf.AddHostKey(testSigners["ecdsa"]) + done := make(chan *server, 1) + go func() { + server, err := newServer(c2, &serverConf) + if err != nil { + done <- nil + } + done <- server + }() + + client, _, reqs, err := NewClientConn(c1, "", &clientConf) + if err != nil { + return nil, nil, err + } + + server := <-done + if server == nil { + return nil, nil, errors.New("server handshake failed.") + } + go DiscardRequests(reqs) + + return client, server, nil +} + +func BenchmarkEndToEnd(b *testing.B) { + b.StopTimer() + + client, server, err := sshPipe() + if err != nil { + b.Fatalf("sshPipe: %v", err) + } + + defer client.Close() + defer server.Close() + + size := (1 << 20) + input := make([]byte, size) + output := make([]byte, size) + b.SetBytes(int64(size)) + done := make(chan int, 1) + + go func() { + newCh, err := server.Accept() + if err != nil { + panic(fmt.Sprintf("Client: %v", err)) + } + ch, incoming, err := newCh.Accept() + if err != nil { + panic(fmt.Sprintf("Accept: %v", err)) + } + go DiscardRequests(incoming) + for i := 0; i < b.N; i++ { + if _, err := io.ReadFull(ch, output); err != nil { + panic(fmt.Sprintf("ReadFull: %v", err)) + } + } + ch.Close() + done <- 1 + }() + + ch, in, err := client.OpenChannel("speed", nil) + if err != nil { + b.Fatalf("OpenChannel: %v", err) + } + go DiscardRequests(in) + + b.ResetTimer() + b.StartTimer() + for i := 0; i < b.N; i++ { + if _, err := ch.Write(input); err != nil { + b.Fatalf("WriteFull: %v", err) + } + } + ch.Close() + b.StopTimer() + + <-done +} diff --git a/tempfork/sshtest/ssh/buffer.go b/tempfork/sshtest/ssh/buffer.go new file mode 100644 index 000000000..1ab07d078 --- /dev/null +++ b/tempfork/sshtest/ssh/buffer.go @@ -0,0 +1,97 @@ +// Copyright 2012 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "io" + "sync" +) + +// buffer provides a linked list buffer for data exchange +// between producer and consumer. Theoretically the buffer is +// of unlimited capacity as it does no allocation of its own. +type buffer struct { + // protects concurrent access to head, tail and closed + *sync.Cond + + head *element // the buffer that will be read first + tail *element // the buffer that will be read last + + closed bool +} + +// An element represents a single link in a linked list. +type element struct { + buf []byte + next *element +} + +// newBuffer returns an empty buffer that is not closed. +func newBuffer() *buffer { + e := new(element) + b := &buffer{ + Cond: newCond(), + head: e, + tail: e, + } + return b +} + +// write makes buf available for Read to receive. +// buf must not be modified after the call to write. +func (b *buffer) write(buf []byte) { + b.Cond.L.Lock() + e := &element{buf: buf} + b.tail.next = e + b.tail = e + b.Cond.Signal() + b.Cond.L.Unlock() +} + +// eof closes the buffer. Reads from the buffer once all +// the data has been consumed will receive io.EOF. +func (b *buffer) eof() { + b.Cond.L.Lock() + b.closed = true + b.Cond.Signal() + b.Cond.L.Unlock() +} + +// Read reads data from the internal buffer in buf. Reads will block +// if no data is available, or until the buffer is closed. +func (b *buffer) Read(buf []byte) (n int, err error) { + b.Cond.L.Lock() + defer b.Cond.L.Unlock() + + for len(buf) > 0 { + // if there is data in b.head, copy it + if len(b.head.buf) > 0 { + r := copy(buf, b.head.buf) + buf, b.head.buf = buf[r:], b.head.buf[r:] + n += r + continue + } + // if there is a next buffer, make it the head + if len(b.head.buf) == 0 && b.head != b.tail { + b.head = b.head.next + continue + } + + // if at least one byte has been copied, return + if n > 0 { + break + } + + // if nothing was read, and there is nothing outstanding + // check to see if the buffer is closed. + if b.closed { + err = io.EOF + break + } + // out of buffers, wait for producer + b.Cond.Wait() + } + return +} diff --git a/tempfork/sshtest/ssh/buffer_test.go b/tempfork/sshtest/ssh/buffer_test.go new file mode 100644 index 000000000..d5781cb3d --- /dev/null +++ b/tempfork/sshtest/ssh/buffer_test.go @@ -0,0 +1,87 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "io" + "testing" +) + +var alphabet = []byte("abcdefghijklmnopqrstuvwxyz") + +func TestBufferReadwrite(t *testing.T) { + b := newBuffer() + b.write(alphabet[:10]) + r, _ := b.Read(make([]byte, 10)) + if r != 10 { + t.Fatalf("Expected written == read == 10, written: 10, read %d", r) + } + + b = newBuffer() + b.write(alphabet[:5]) + r, _ = b.Read(make([]byte, 10)) + if r != 5 { + t.Fatalf("Expected written == read == 5, written: 5, read %d", r) + } + + b = newBuffer() + b.write(alphabet[:10]) + r, _ = b.Read(make([]byte, 5)) + if r != 5 { + t.Fatalf("Expected written == 10, read == 5, written: 10, read %d", r) + } + + b = newBuffer() + b.write(alphabet[:5]) + b.write(alphabet[5:15]) + r, _ = b.Read(make([]byte, 10)) + r2, _ := b.Read(make([]byte, 10)) + if r != 10 || r2 != 5 || 15 != r+r2 { + t.Fatal("Expected written == read == 15") + } +} + +func TestBufferClose(t *testing.T) { + b := newBuffer() + b.write(alphabet[:10]) + b.eof() + _, err := b.Read(make([]byte, 5)) + if err != nil { + t.Fatal("expected read of 5 to not return EOF") + } + b = newBuffer() + b.write(alphabet[:10]) + b.eof() + r, err := b.Read(make([]byte, 5)) + r2, err2 := b.Read(make([]byte, 10)) + if r != 5 || r2 != 5 || err != nil || err2 != nil { + t.Fatal("expected reads of 5 and 5") + } + + b = newBuffer() + b.write(alphabet[:10]) + b.eof() + r, err = b.Read(make([]byte, 5)) + r2, err2 = b.Read(make([]byte, 10)) + r3, err3 := b.Read(make([]byte, 10)) + if r != 5 || r2 != 5 || r3 != 0 || err != nil || err2 != nil || err3 != io.EOF { + t.Fatal("expected reads of 5 and 5 and 0, with EOF") + } + + b = newBuffer() + b.write(make([]byte, 5)) + b.write(make([]byte, 10)) + b.eof() + r, err = b.Read(make([]byte, 9)) + r2, err2 = b.Read(make([]byte, 3)) + r3, err3 = b.Read(make([]byte, 3)) + r4, err4 := b.Read(make([]byte, 10)) + if err != nil || err2 != nil || err3 != nil || err4 != io.EOF { + t.Fatalf("Expected EOF on forth read only, err=%v, err2=%v, err3=%v, err4=%v", err, err2, err3, err4) + } + if r != 9 || r2 != 3 || r3 != 3 || r4 != 0 { + t.Fatal("Expected written == read == 15", r, r2, r3, r4) + } +} diff --git a/tempfork/sshtest/ssh/certs.go b/tempfork/sshtest/ssh/certs.go new file mode 100644 index 000000000..27d0e14aa --- /dev/null +++ b/tempfork/sshtest/ssh/certs.go @@ -0,0 +1,611 @@ +// Copyright 2012 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "bytes" + "errors" + "fmt" + "io" + "net" + "sort" + "time" +) + +// Certificate algorithm names from [PROTOCOL.certkeys]. These values can appear +// in Certificate.Type, PublicKey.Type, and ClientConfig.HostKeyAlgorithms. +// Unlike key algorithm names, these are not passed to AlgorithmSigner nor +// returned by MultiAlgorithmSigner and don't appear in the Signature.Format +// field. +const ( + CertAlgoRSAv01 = "ssh-rsa-cert-v01@openssh.com" + CertAlgoDSAv01 = "ssh-dss-cert-v01@openssh.com" + CertAlgoECDSA256v01 = "ecdsa-sha2-nistp256-cert-v01@openssh.com" + CertAlgoECDSA384v01 = "ecdsa-sha2-nistp384-cert-v01@openssh.com" + CertAlgoECDSA521v01 = "ecdsa-sha2-nistp521-cert-v01@openssh.com" + CertAlgoSKECDSA256v01 = "sk-ecdsa-sha2-nistp256-cert-v01@openssh.com" + CertAlgoED25519v01 = "ssh-ed25519-cert-v01@openssh.com" + CertAlgoSKED25519v01 = "sk-ssh-ed25519-cert-v01@openssh.com" + + // CertAlgoRSASHA256v01 and CertAlgoRSASHA512v01 can't appear as a + // Certificate.Type (or PublicKey.Type), but only in + // ClientConfig.HostKeyAlgorithms. + CertAlgoRSASHA256v01 = "rsa-sha2-256-cert-v01@openssh.com" + CertAlgoRSASHA512v01 = "rsa-sha2-512-cert-v01@openssh.com" +) + +const ( + // Deprecated: use CertAlgoRSAv01. + CertSigAlgoRSAv01 = CertAlgoRSAv01 + // Deprecated: use CertAlgoRSASHA256v01. + CertSigAlgoRSASHA2256v01 = CertAlgoRSASHA256v01 + // Deprecated: use CertAlgoRSASHA512v01. + CertSigAlgoRSASHA2512v01 = CertAlgoRSASHA512v01 +) + +// Certificate types distinguish between host and user +// certificates. The values can be set in the CertType field of +// Certificate. +const ( + UserCert = 1 + HostCert = 2 +) + +// Signature represents a cryptographic signature. +type Signature struct { + Format string + Blob []byte + Rest []byte `ssh:"rest"` +} + +// CertTimeInfinity can be used for OpenSSHCertV01.ValidBefore to indicate that +// a certificate does not expire. +const CertTimeInfinity = 1<<64 - 1 + +// An Certificate represents an OpenSSH certificate as defined in +// [PROTOCOL.certkeys]?rev=1.8. The Certificate type implements the +// PublicKey interface, so it can be unmarshaled using +// ParsePublicKey. +type Certificate struct { + Nonce []byte + Key PublicKey + Serial uint64 + CertType uint32 + KeyId string + ValidPrincipals []string + ValidAfter uint64 + ValidBefore uint64 + Permissions + Reserved []byte + SignatureKey PublicKey + Signature *Signature +} + +// genericCertData holds the key-independent part of the certificate data. +// Overall, certificates contain an nonce, public key fields and +// key-independent fields. +type genericCertData struct { + Serial uint64 + CertType uint32 + KeyId string + ValidPrincipals []byte + ValidAfter uint64 + ValidBefore uint64 + CriticalOptions []byte + Extensions []byte + Reserved []byte + SignatureKey []byte + Signature []byte +} + +func marshalStringList(namelist []string) []byte { + var to []byte + for _, name := range namelist { + s := struct{ N string }{name} + to = append(to, Marshal(&s)...) + } + return to +} + +type optionsTuple struct { + Key string + Value []byte +} + +type optionsTupleValue struct { + Value string +} + +// serialize a map of critical options or extensions +// issue #10569 - per [PROTOCOL.certkeys] and SSH implementation, +// we need two length prefixes for a non-empty string value +func marshalTuples(tups map[string]string) []byte { + keys := make([]string, 0, len(tups)) + for key := range tups { + keys = append(keys, key) + } + sort.Strings(keys) + + var ret []byte + for _, key := range keys { + s := optionsTuple{Key: key} + if value := tups[key]; len(value) > 0 { + s.Value = Marshal(&optionsTupleValue{value}) + } + ret = append(ret, Marshal(&s)...) + } + return ret +} + +// issue #10569 - per [PROTOCOL.certkeys] and SSH implementation, +// we need two length prefixes for a non-empty option value +func parseTuples(in []byte) (map[string]string, error) { + tups := map[string]string{} + var lastKey string + var haveLastKey bool + + for len(in) > 0 { + var key, val, extra []byte + var ok bool + + if key, in, ok = parseString(in); !ok { + return nil, errShortRead + } + keyStr := string(key) + // according to [PROTOCOL.certkeys], the names must be in + // lexical order. + if haveLastKey && keyStr <= lastKey { + return nil, fmt.Errorf("ssh: certificate options are not in lexical order") + } + lastKey, haveLastKey = keyStr, true + // the next field is a data field, which if non-empty has a string embedded + if val, in, ok = parseString(in); !ok { + return nil, errShortRead + } + if len(val) > 0 { + val, extra, ok = parseString(val) + if !ok { + return nil, errShortRead + } + if len(extra) > 0 { + return nil, fmt.Errorf("ssh: unexpected trailing data after certificate option value") + } + tups[keyStr] = string(val) + } else { + tups[keyStr] = "" + } + } + return tups, nil +} + +func parseCert(in []byte, privAlgo string) (*Certificate, error) { + nonce, rest, ok := parseString(in) + if !ok { + return nil, errShortRead + } + + key, rest, err := parsePubKey(rest, privAlgo) + if err != nil { + return nil, err + } + + var g genericCertData + if err := Unmarshal(rest, &g); err != nil { + return nil, err + } + + c := &Certificate{ + Nonce: nonce, + Key: key, + Serial: g.Serial, + CertType: g.CertType, + KeyId: g.KeyId, + ValidAfter: g.ValidAfter, + ValidBefore: g.ValidBefore, + } + + for principals := g.ValidPrincipals; len(principals) > 0; { + principal, rest, ok := parseString(principals) + if !ok { + return nil, errShortRead + } + c.ValidPrincipals = append(c.ValidPrincipals, string(principal)) + principals = rest + } + + c.CriticalOptions, err = parseTuples(g.CriticalOptions) + if err != nil { + return nil, err + } + c.Extensions, err = parseTuples(g.Extensions) + if err != nil { + return nil, err + } + c.Reserved = g.Reserved + k, err := ParsePublicKey(g.SignatureKey) + if err != nil { + return nil, err + } + + c.SignatureKey = k + c.Signature, rest, ok = parseSignatureBody(g.Signature) + if !ok || len(rest) > 0 { + return nil, errors.New("ssh: signature parse error") + } + + return c, nil +} + +type openSSHCertSigner struct { + pub *Certificate + signer Signer +} + +type algorithmOpenSSHCertSigner struct { + *openSSHCertSigner + algorithmSigner AlgorithmSigner +} + +// NewCertSigner returns a Signer that signs with the given Certificate, whose +// private key is held by signer. It returns an error if the public key in cert +// doesn't match the key used by signer. +func NewCertSigner(cert *Certificate, signer Signer) (Signer, error) { + if !bytes.Equal(cert.Key.Marshal(), signer.PublicKey().Marshal()) { + return nil, errors.New("ssh: signer and cert have different public key") + } + + switch s := signer.(type) { + case MultiAlgorithmSigner: + return &multiAlgorithmSigner{ + AlgorithmSigner: &algorithmOpenSSHCertSigner{ + &openSSHCertSigner{cert, signer}, s}, + supportedAlgorithms: s.Algorithms(), + }, nil + case AlgorithmSigner: + return &algorithmOpenSSHCertSigner{ + &openSSHCertSigner{cert, signer}, s}, nil + default: + return &openSSHCertSigner{cert, signer}, nil + } +} + +func (s *openSSHCertSigner) Sign(rand io.Reader, data []byte) (*Signature, error) { + return s.signer.Sign(rand, data) +} + +func (s *openSSHCertSigner) PublicKey() PublicKey { + return s.pub +} + +func (s *algorithmOpenSSHCertSigner) SignWithAlgorithm(rand io.Reader, data []byte, algorithm string) (*Signature, error) { + return s.algorithmSigner.SignWithAlgorithm(rand, data, algorithm) +} + +const sourceAddressCriticalOption = "source-address" + +// CertChecker does the work of verifying a certificate. Its methods +// can be plugged into ClientConfig.HostKeyCallback and +// ServerConfig.PublicKeyCallback. For the CertChecker to work, +// minimally, the IsAuthority callback should be set. +type CertChecker struct { + // SupportedCriticalOptions lists the CriticalOptions that the + // server application layer understands. These are only used + // for user certificates. + SupportedCriticalOptions []string + + // IsUserAuthority should return true if the key is recognized as an + // authority for the given user certificate. This allows for + // certificates to be signed by other certificates. This must be set + // if this CertChecker will be checking user certificates. + IsUserAuthority func(auth PublicKey) bool + + // IsHostAuthority should report whether the key is recognized as + // an authority for this host. This allows for certificates to be + // signed by other keys, and for those other keys to only be valid + // signers for particular hostnames. This must be set if this + // CertChecker will be checking host certificates. + IsHostAuthority func(auth PublicKey, address string) bool + + // Clock is used for verifying time stamps. If nil, time.Now + // is used. + Clock func() time.Time + + // UserKeyFallback is called when CertChecker.Authenticate encounters a + // public key that is not a certificate. It must implement validation + // of user keys or else, if nil, all such keys are rejected. + UserKeyFallback func(conn ConnMetadata, key PublicKey) (*Permissions, error) + + // HostKeyFallback is called when CertChecker.CheckHostKey encounters a + // public key that is not a certificate. It must implement host key + // validation or else, if nil, all such keys are rejected. + HostKeyFallback HostKeyCallback + + // IsRevoked is called for each certificate so that revocation checking + // can be implemented. It should return true if the given certificate + // is revoked and false otherwise. If nil, no certificates are + // considered to have been revoked. + IsRevoked func(cert *Certificate) bool +} + +// CheckHostKey checks a host key certificate. This method can be +// plugged into ClientConfig.HostKeyCallback. +func (c *CertChecker) CheckHostKey(addr string, remote net.Addr, key PublicKey) error { + cert, ok := key.(*Certificate) + if !ok { + if c.HostKeyFallback != nil { + return c.HostKeyFallback(addr, remote, key) + } + return errors.New("ssh: non-certificate host key") + } + if cert.CertType != HostCert { + return fmt.Errorf("ssh: certificate presented as a host key has type %d", cert.CertType) + } + if !c.IsHostAuthority(cert.SignatureKey, addr) { + return fmt.Errorf("ssh: no authorities for hostname: %v", addr) + } + + hostname, _, err := net.SplitHostPort(addr) + if err != nil { + return err + } + + // Pass hostname only as principal for host certificates (consistent with OpenSSH) + return c.CheckCert(hostname, cert) +} + +// Authenticate checks a user certificate. Authenticate can be used as +// a value for ServerConfig.PublicKeyCallback. +func (c *CertChecker) Authenticate(conn ConnMetadata, pubKey PublicKey) (*Permissions, error) { + cert, ok := pubKey.(*Certificate) + if !ok { + if c.UserKeyFallback != nil { + return c.UserKeyFallback(conn, pubKey) + } + return nil, errors.New("ssh: normal key pairs not accepted") + } + + if cert.CertType != UserCert { + return nil, fmt.Errorf("ssh: cert has type %d", cert.CertType) + } + if !c.IsUserAuthority(cert.SignatureKey) { + return nil, fmt.Errorf("ssh: certificate signed by unrecognized authority") + } + + if err := c.CheckCert(conn.User(), cert); err != nil { + return nil, err + } + + return &cert.Permissions, nil +} + +// CheckCert checks CriticalOptions, ValidPrincipals, revocation, timestamp and +// the signature of the certificate. +func (c *CertChecker) CheckCert(principal string, cert *Certificate) error { + if c.IsRevoked != nil && c.IsRevoked(cert) { + return fmt.Errorf("ssh: certificate serial %d revoked", cert.Serial) + } + + for opt := range cert.CriticalOptions { + // sourceAddressCriticalOption will be enforced by + // serverAuthenticate + if opt == sourceAddressCriticalOption { + continue + } + + found := false + for _, supp := range c.SupportedCriticalOptions { + if supp == opt { + found = true + break + } + } + if !found { + return fmt.Errorf("ssh: unsupported critical option %q in certificate", opt) + } + } + + if len(cert.ValidPrincipals) > 0 { + // By default, certs are valid for all users/hosts. + found := false + for _, p := range cert.ValidPrincipals { + if p == principal { + found = true + break + } + } + if !found { + return fmt.Errorf("ssh: principal %q not in the set of valid principals for given certificate: %q", principal, cert.ValidPrincipals) + } + } + + clock := c.Clock + if clock == nil { + clock = time.Now + } + + unixNow := clock().Unix() + if after := int64(cert.ValidAfter); after < 0 || unixNow < int64(cert.ValidAfter) { + return fmt.Errorf("ssh: cert is not yet valid") + } + if before := int64(cert.ValidBefore); cert.ValidBefore != uint64(CertTimeInfinity) && (unixNow >= before || before < 0) { + return fmt.Errorf("ssh: cert has expired") + } + if err := cert.SignatureKey.Verify(cert.bytesForSigning(), cert.Signature); err != nil { + return fmt.Errorf("ssh: certificate signature does not verify") + } + + return nil +} + +// SignCert signs the certificate with an authority, setting the Nonce, +// SignatureKey, and Signature fields. If the authority implements the +// MultiAlgorithmSigner interface the first algorithm in the list is used. This +// is useful if you want to sign with a specific algorithm. +func (c *Certificate) SignCert(rand io.Reader, authority Signer) error { + c.Nonce = make([]byte, 32) + if _, err := io.ReadFull(rand, c.Nonce); err != nil { + return err + } + c.SignatureKey = authority.PublicKey() + + if v, ok := authority.(MultiAlgorithmSigner); ok { + if len(v.Algorithms()) == 0 { + return errors.New("the provided authority has no signature algorithm") + } + // Use the first algorithm in the list. + sig, err := v.SignWithAlgorithm(rand, c.bytesForSigning(), v.Algorithms()[0]) + if err != nil { + return err + } + c.Signature = sig + return nil + } else if v, ok := authority.(AlgorithmSigner); ok && v.PublicKey().Type() == KeyAlgoRSA { + // Default to KeyAlgoRSASHA512 for ssh-rsa signers. + // TODO: consider using KeyAlgoRSASHA256 as default. + sig, err := v.SignWithAlgorithm(rand, c.bytesForSigning(), KeyAlgoRSASHA512) + if err != nil { + return err + } + c.Signature = sig + return nil + } + + sig, err := authority.Sign(rand, c.bytesForSigning()) + if err != nil { + return err + } + c.Signature = sig + return nil +} + +// certKeyAlgoNames is a mapping from known certificate algorithm names to the +// corresponding public key signature algorithm. +// +// This map must be kept in sync with the one in agent/client.go. +var certKeyAlgoNames = map[string]string{ + CertAlgoRSAv01: KeyAlgoRSA, + CertAlgoRSASHA256v01: KeyAlgoRSASHA256, + CertAlgoRSASHA512v01: KeyAlgoRSASHA512, + CertAlgoDSAv01: KeyAlgoDSA, + CertAlgoECDSA256v01: KeyAlgoECDSA256, + CertAlgoECDSA384v01: KeyAlgoECDSA384, + CertAlgoECDSA521v01: KeyAlgoECDSA521, + CertAlgoSKECDSA256v01: KeyAlgoSKECDSA256, + CertAlgoED25519v01: KeyAlgoED25519, + CertAlgoSKED25519v01: KeyAlgoSKED25519, +} + +// underlyingAlgo returns the signature algorithm associated with algo (which is +// an advertised or negotiated public key or host key algorithm). These are +// usually the same, except for certificate algorithms. +func underlyingAlgo(algo string) string { + if a, ok := certKeyAlgoNames[algo]; ok { + return a + } + return algo +} + +// certificateAlgo returns the certificate algorithms that uses the provided +// underlying signature algorithm. +func certificateAlgo(algo string) (certAlgo string, ok bool) { + for certName, algoName := range certKeyAlgoNames { + if algoName == algo { + return certName, true + } + } + return "", false +} + +func (cert *Certificate) bytesForSigning() []byte { + c2 := *cert + c2.Signature = nil + out := c2.Marshal() + // Drop trailing signature length. + return out[:len(out)-4] +} + +// Marshal serializes c into OpenSSH's wire format. It is part of the +// PublicKey interface. +func (c *Certificate) Marshal() []byte { + generic := genericCertData{ + Serial: c.Serial, + CertType: c.CertType, + KeyId: c.KeyId, + ValidPrincipals: marshalStringList(c.ValidPrincipals), + ValidAfter: uint64(c.ValidAfter), + ValidBefore: uint64(c.ValidBefore), + CriticalOptions: marshalTuples(c.CriticalOptions), + Extensions: marshalTuples(c.Extensions), + Reserved: c.Reserved, + SignatureKey: c.SignatureKey.Marshal(), + } + if c.Signature != nil { + generic.Signature = Marshal(c.Signature) + } + genericBytes := Marshal(&generic) + keyBytes := c.Key.Marshal() + _, keyBytes, _ = parseString(keyBytes) + prefix := Marshal(&struct { + Name string + Nonce []byte + Key []byte `ssh:"rest"` + }{c.Type(), c.Nonce, keyBytes}) + + result := make([]byte, 0, len(prefix)+len(genericBytes)) + result = append(result, prefix...) + result = append(result, genericBytes...) + return result +} + +// Type returns the certificate algorithm name. It is part of the PublicKey interface. +func (c *Certificate) Type() string { + certName, ok := certificateAlgo(c.Key.Type()) + if !ok { + panic("unknown certificate type for key type " + c.Key.Type()) + } + return certName +} + +// Verify verifies a signature against the certificate's public +// key. It is part of the PublicKey interface. +func (c *Certificate) Verify(data []byte, sig *Signature) error { + return c.Key.Verify(data, sig) +} + +func parseSignatureBody(in []byte) (out *Signature, rest []byte, ok bool) { + format, in, ok := parseString(in) + if !ok { + return + } + + out = &Signature{ + Format: string(format), + } + + if out.Blob, in, ok = parseString(in); !ok { + return + } + + switch out.Format { + case KeyAlgoSKECDSA256, CertAlgoSKECDSA256v01, KeyAlgoSKED25519, CertAlgoSKED25519v01: + out.Rest = in + return out, nil, ok + } + + return out, in, ok +} + +func parseSignature(in []byte) (out *Signature, rest []byte, ok bool) { + sigBytes, rest, ok := parseString(in) + if !ok { + return + } + + out, trailing, ok := parseSignatureBody(sigBytes) + if !ok || len(trailing) > 0 { + return nil, nil, false + } + return +} diff --git a/tempfork/sshtest/ssh/certs_test.go b/tempfork/sshtest/ssh/certs_test.go new file mode 100644 index 000000000..6208bb37a --- /dev/null +++ b/tempfork/sshtest/ssh/certs_test.go @@ -0,0 +1,406 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "bytes" + "crypto/ecdsa" + "crypto/elliptic" + "crypto/rand" + "fmt" + "io" + "net" + "reflect" + "testing" + "time" + + "golang.org/x/crypto/ssh/testdata" +) + +func TestParseCert(t *testing.T) { + authKeyBytes := bytes.TrimSuffix(testdata.SSHCertificates["rsa"], []byte(" host.example.com\n")) + + key, _, _, rest, err := ParseAuthorizedKey(authKeyBytes) + if err != nil { + t.Fatalf("ParseAuthorizedKey: %v", err) + } + if len(rest) > 0 { + t.Errorf("rest: got %q, want empty", rest) + } + + if _, ok := key.(*Certificate); !ok { + t.Fatalf("got %v (%T), want *Certificate", key, key) + } + + marshaled := MarshalAuthorizedKey(key) + // Before comparison, remove the trailing newline that + // MarshalAuthorizedKey adds. + marshaled = marshaled[:len(marshaled)-1] + if !bytes.Equal(authKeyBytes, marshaled) { + t.Errorf("marshaled certificate does not match original: got %q, want %q", marshaled, authKeyBytes) + } +} + +// Cert generated by ssh-keygen OpenSSH_6.8p1 OS X 10.10.3 +// % ssh-keygen -s ca -I testcert -O source-address=192.168.1.0/24 -O force-command=/bin/sleep user.pub +// user.pub key: ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDACh1rt2DXfV3hk6fszSQcQ/rueMId0kVD9U7nl8cfEnFxqOCrNT92g4laQIGl2mn8lsGZfTLg8ksHq3gkvgO3oo/0wHy4v32JeBOHTsN5AL4gfHNEhWeWb50ev47hnTsRIt9P4dxogeUo/hTu7j9+s9lLpEQXCvq6xocXQt0j8MV9qZBBXFLXVT3cWIkSqOdwt/5ZBg+1GSrc7WfCXVWgTk4a20uPMuJPxU4RQwZW6X3+O8Pqo8C3cW0OzZRFP6gUYUKUsTI5WntlS+LAxgw1mZNsozFGdbiOPRnEryE3SRldh9vjDR3tin1fGpA5P7+CEB/bqaXtG3V+F2OkqaMN +// Critical Options: +// +// force-command /bin/sleep +// source-address 192.168.1.0/24 +// +// Extensions: +// +// permit-X11-forwarding +// permit-agent-forwarding +// permit-port-forwarding +// permit-pty +// permit-user-rc +const exampleSSHCertWithOptions = `ssh-rsa-cert-v01@openssh.com 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` + +func TestParseCertWithOptions(t *testing.T) { + opts := map[string]string{ + "source-address": "192.168.1.0/24", + "force-command": "/bin/sleep", + } + exts := map[string]string{ + "permit-X11-forwarding": "", + "permit-agent-forwarding": "", + "permit-port-forwarding": "", + "permit-pty": "", + "permit-user-rc": "", + } + authKeyBytes := []byte(exampleSSHCertWithOptions) + + key, _, _, rest, err := ParseAuthorizedKey(authKeyBytes) + if err != nil { + t.Fatalf("ParseAuthorizedKey: %v", err) + } + if len(rest) > 0 { + t.Errorf("rest: got %q, want empty", rest) + } + cert, ok := key.(*Certificate) + if !ok { + t.Fatalf("got %v (%T), want *Certificate", key, key) + } + if !reflect.DeepEqual(cert.CriticalOptions, opts) { + t.Errorf("unexpected critical options - got %v, want %v", cert.CriticalOptions, opts) + } + if !reflect.DeepEqual(cert.Extensions, exts) { + t.Errorf("unexpected Extensions - got %v, want %v", cert.Extensions, exts) + } + marshaled := MarshalAuthorizedKey(key) + // Before comparison, remove the trailing newline that + // MarshalAuthorizedKey adds. + marshaled = marshaled[:len(marshaled)-1] + if !bytes.Equal(authKeyBytes, marshaled) { + t.Errorf("marshaled certificate does not match original: got %q, want %q", marshaled, authKeyBytes) + } +} + +func TestValidateCert(t *testing.T) { + key, _, _, _, err := ParseAuthorizedKey(testdata.SSHCertificates["rsa-user-testcertificate"]) + if err != nil { + t.Fatalf("ParseAuthorizedKey: %v", err) + } + validCert, ok := key.(*Certificate) + if !ok { + t.Fatalf("got %v (%T), want *Certificate", key, key) + } + checker := CertChecker{} + checker.IsUserAuthority = func(k PublicKey) bool { + return bytes.Equal(k.Marshal(), validCert.SignatureKey.Marshal()) + } + + if err := checker.CheckCert("testcertificate", validCert); err != nil { + t.Errorf("Unable to validate certificate: %v", err) + } + invalidCert := &Certificate{ + Key: testPublicKeys["rsa"], + SignatureKey: testPublicKeys["ecdsa"], + ValidBefore: CertTimeInfinity, + Signature: &Signature{}, + } + if err := checker.CheckCert("testcertificate", invalidCert); err == nil { + t.Error("Invalid cert signature passed validation") + } +} + +func TestValidateCertTime(t *testing.T) { + cert := Certificate{ + ValidPrincipals: []string{"user"}, + Key: testPublicKeys["rsa"], + ValidAfter: 50, + ValidBefore: 100, + } + + cert.SignCert(rand.Reader, testSigners["ecdsa"]) + + for ts, ok := range map[int64]bool{ + 25: false, + 50: true, + 99: true, + 100: false, + 125: false, + } { + checker := CertChecker{ + Clock: func() time.Time { return time.Unix(ts, 0) }, + } + checker.IsUserAuthority = func(k PublicKey) bool { + return bytes.Equal(k.Marshal(), + testPublicKeys["ecdsa"].Marshal()) + } + + if v := checker.CheckCert("user", &cert); (v == nil) != ok { + t.Errorf("Authenticate(%d): %v", ts, v) + } + } +} + +// TODO(hanwen): tests for +// +// host keys: +// * fallbacks + +func TestHostKeyCert(t *testing.T) { + cert := &Certificate{ + ValidPrincipals: []string{"hostname", "hostname.domain", "otherhost"}, + Key: testPublicKeys["rsa"], + ValidBefore: CertTimeInfinity, + CertType: HostCert, + } + cert.SignCert(rand.Reader, testSigners["ecdsa"]) + + checker := &CertChecker{ + IsHostAuthority: func(p PublicKey, addr string) bool { + return addr == "hostname:22" && bytes.Equal(testPublicKeys["ecdsa"].Marshal(), p.Marshal()) + }, + } + + certSigner, err := NewCertSigner(cert, testSigners["rsa"]) + if err != nil { + t.Errorf("NewCertSigner: %v", err) + } + + for _, test := range []struct { + addr string + succeed bool + certSignerAlgorithms []string // Empty means no algorithm restrictions. + clientHostKeyAlgorithms []string + }{ + {addr: "hostname:22", succeed: true}, + { + addr: "hostname:22", + succeed: true, + certSignerAlgorithms: []string{KeyAlgoRSASHA256, KeyAlgoRSASHA512}, + clientHostKeyAlgorithms: []string{CertAlgoRSASHA512v01}, + }, + { + addr: "hostname:22", + succeed: false, + certSignerAlgorithms: []string{KeyAlgoRSASHA256, KeyAlgoRSASHA512}, + clientHostKeyAlgorithms: []string{CertAlgoRSAv01}, + }, + { + addr: "hostname:22", + succeed: false, + certSignerAlgorithms: []string{KeyAlgoRSASHA256, KeyAlgoRSASHA512}, + clientHostKeyAlgorithms: []string{KeyAlgoRSASHA512}, // Not a certificate algorithm. + }, + {addr: "otherhost:22", succeed: false}, // The certificate is valid for 'otherhost' as hostname, but we only recognize the authority of the signer for the address 'hostname:22' + {addr: "lasthost:22", succeed: false}, + } { + c1, c2, err := netPipe() + if err != nil { + t.Fatalf("netPipe: %v", err) + } + defer c1.Close() + defer c2.Close() + + errc := make(chan error) + + go func() { + conf := ServerConfig{ + NoClientAuth: true, + } + if len(test.certSignerAlgorithms) > 0 { + mas, err := NewSignerWithAlgorithms(certSigner.(AlgorithmSigner), test.certSignerAlgorithms) + if err != nil { + errc <- err + return + } + conf.AddHostKey(mas) + } else { + conf.AddHostKey(certSigner) + } + _, _, _, err := NewServerConn(c1, &conf) + errc <- err + }() + + config := &ClientConfig{ + User: "user", + HostKeyCallback: checker.CheckHostKey, + HostKeyAlgorithms: test.clientHostKeyAlgorithms, + } + _, _, _, err = NewClientConn(c2, test.addr, config) + + if (err == nil) != test.succeed { + t.Errorf("NewClientConn(%q): %v", test.addr, err) + } + + err = <-errc + if (err == nil) != test.succeed { + t.Errorf("NewServerConn(%q): %v", test.addr, err) + } + } +} + +type legacyRSASigner struct { + Signer +} + +func (s *legacyRSASigner) Sign(rand io.Reader, data []byte) (*Signature, error) { + v, ok := s.Signer.(AlgorithmSigner) + if !ok { + return nil, fmt.Errorf("invalid signer") + } + return v.SignWithAlgorithm(rand, data, KeyAlgoRSA) +} + +func TestCertTypes(t *testing.T) { + algorithmSigner, ok := testSigners["rsa"].(AlgorithmSigner) + if !ok { + t.Fatal("rsa test signer does not implement the AlgorithmSigner interface") + } + multiAlgoSignerSHA256, err := NewSignerWithAlgorithms(algorithmSigner, []string{KeyAlgoRSASHA256}) + if err != nil { + t.Fatalf("unable to create multi algorithm signer SHA256: %v", err) + } + // Algorithms are in order of preference, we expect rsa-sha2-512 to be used. + multiAlgoSignerSHA512, err := NewSignerWithAlgorithms(algorithmSigner, []string{KeyAlgoRSASHA512, KeyAlgoRSASHA256}) + if err != nil { + t.Fatalf("unable to create multi algorithm signer SHA512: %v", err) + } + + var testVars = []struct { + name string + signer Signer + algo string + }{ + {CertAlgoECDSA256v01, testSigners["ecdsap256"], ""}, + {CertAlgoECDSA384v01, testSigners["ecdsap384"], ""}, + {CertAlgoECDSA521v01, testSigners["ecdsap521"], ""}, + {CertAlgoED25519v01, testSigners["ed25519"], ""}, + {CertAlgoRSAv01, testSigners["rsa"], KeyAlgoRSASHA256}, + {"legacyRSASigner", &legacyRSASigner{testSigners["rsa"]}, KeyAlgoRSA}, + {"multiAlgoRSASignerSHA256", multiAlgoSignerSHA256, KeyAlgoRSASHA256}, + {"multiAlgoRSASignerSHA512", multiAlgoSignerSHA512, KeyAlgoRSASHA512}, + {CertAlgoDSAv01, testSigners["dsa"], ""}, + } + + k, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader) + if err != nil { + t.Fatalf("error generating host key: %v", err) + } + + signer, err := NewSignerFromKey(k) + if err != nil { + t.Fatalf("error generating signer for ssh listener: %v", err) + } + + conf := &ServerConfig{ + PublicKeyCallback: func(c ConnMetadata, k PublicKey) (*Permissions, error) { + return new(Permissions), nil + }, + } + conf.AddHostKey(signer) + + for _, m := range testVars { + t.Run(m.name, func(t *testing.T) { + + c1, c2, err := netPipe() + if err != nil { + t.Fatalf("netPipe: %v", err) + } + defer c1.Close() + defer c2.Close() + + go NewServerConn(c1, conf) + + priv := m.signer + if err != nil { + t.Fatalf("error generating ssh pubkey: %v", err) + } + + cert := &Certificate{ + CertType: UserCert, + Key: priv.PublicKey(), + } + cert.SignCert(rand.Reader, priv) + + certSigner, err := NewCertSigner(cert, priv) + if err != nil { + t.Fatalf("error generating cert signer: %v", err) + } + + if m.algo != "" && cert.Signature.Format != m.algo { + t.Errorf("expected %q signature format, got %q", m.algo, cert.Signature.Format) + } + + config := &ClientConfig{ + User: "user", + HostKeyCallback: func(h string, r net.Addr, k PublicKey) error { return nil }, + Auth: []AuthMethod{PublicKeys(certSigner)}, + } + + _, _, _, err = NewClientConn(c2, "", config) + if err != nil { + t.Fatalf("error connecting: %v", err) + } + }) + } +} + +func TestCertSignWithMultiAlgorithmSigner(t *testing.T) { + type testcase struct { + sigAlgo string + algorithms []string + } + cases := []testcase{ + { + sigAlgo: KeyAlgoRSA, + algorithms: []string{KeyAlgoRSA, KeyAlgoRSASHA512}, + }, + { + sigAlgo: KeyAlgoRSASHA256, + algorithms: []string{KeyAlgoRSASHA256, KeyAlgoRSA, KeyAlgoRSASHA512}, + }, + { + sigAlgo: KeyAlgoRSASHA512, + algorithms: []string{KeyAlgoRSASHA512, KeyAlgoRSASHA256}, + }, + } + + cert := &Certificate{ + Key: testPublicKeys["rsa"], + ValidBefore: CertTimeInfinity, + CertType: UserCert, + } + + for _, c := range cases { + t.Run(c.sigAlgo, func(t *testing.T) { + signer, err := NewSignerWithAlgorithms(testSigners["rsa"].(AlgorithmSigner), c.algorithms) + if err != nil { + t.Fatalf("NewSignerWithAlgorithms error: %v", err) + } + if err := cert.SignCert(rand.Reader, signer); err != nil { + t.Fatalf("SignCert error: %v", err) + } + if cert.Signature.Format != c.sigAlgo { + t.Fatalf("got signature format %q, want %q", cert.Signature.Format, c.sigAlgo) + } + }) + } +} diff --git a/tempfork/sshtest/ssh/channel.go b/tempfork/sshtest/ssh/channel.go new file mode 100644 index 000000000..cc0bb7ab6 --- /dev/null +++ b/tempfork/sshtest/ssh/channel.go @@ -0,0 +1,645 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "encoding/binary" + "errors" + "fmt" + "io" + "log" + "sync" +) + +const ( + minPacketLength = 9 + // channelMaxPacket contains the maximum number of bytes that will be + // sent in a single packet. As per RFC 4253, section 6.1, 32k is also + // the minimum. + channelMaxPacket = 1 << 15 + // We follow OpenSSH here. + channelWindowSize = 64 * channelMaxPacket +) + +// NewChannel represents an incoming request to a channel. It must either be +// accepted for use by calling Accept, or rejected by calling Reject. +type NewChannel interface { + // Accept accepts the channel creation request. It returns the Channel + // and a Go channel containing SSH requests. The Go channel must be + // serviced otherwise the Channel will hang. + Accept() (Channel, <-chan *Request, error) + + // Reject rejects the channel creation request. After calling + // this, no other methods on the Channel may be called. + Reject(reason RejectionReason, message string) error + + // ChannelType returns the type of the channel, as supplied by the + // client. + ChannelType() string + + // ExtraData returns the arbitrary payload for this channel, as supplied + // by the client. This data is specific to the channel type. + ExtraData() []byte +} + +// A Channel is an ordered, reliable, flow-controlled, duplex stream +// that is multiplexed over an SSH connection. +type Channel interface { + // Read reads up to len(data) bytes from the channel. + Read(data []byte) (int, error) + + // Write writes len(data) bytes to the channel. + Write(data []byte) (int, error) + + // Close signals end of channel use. No data may be sent after this + // call. + Close() error + + // CloseWrite signals the end of sending in-band + // data. Requests may still be sent, and the other side may + // still send data + CloseWrite() error + + // SendRequest sends a channel request. If wantReply is true, + // it will wait for a reply and return the result as a + // boolean, otherwise the return value will be false. Channel + // requests are out-of-band messages so they may be sent even + // if the data stream is closed or blocked by flow control. + // If the channel is closed before a reply is returned, io.EOF + // is returned. + SendRequest(name string, wantReply bool, payload []byte) (bool, error) + + // Stderr returns an io.ReadWriter that writes to this channel + // with the extended data type set to stderr. Stderr may + // safely be read and written from a different goroutine than + // Read and Write respectively. + Stderr() io.ReadWriter +} + +// Request is a request sent outside of the normal stream of +// data. Requests can either be specific to an SSH channel, or they +// can be global. +type Request struct { + Type string + WantReply bool + Payload []byte + + ch *channel + mux *mux +} + +// Reply sends a response to a request. It must be called for all requests +// where WantReply is true and is a no-op otherwise. The payload argument is +// ignored for replies to channel-specific requests. +func (r *Request) Reply(ok bool, payload []byte) error { + if !r.WantReply { + return nil + } + + if r.ch == nil { + return r.mux.ackRequest(ok, payload) + } + + return r.ch.ackRequest(ok) +} + +// RejectionReason is an enumeration used when rejecting channel creation +// requests. See RFC 4254, section 5.1. +type RejectionReason uint32 + +const ( + Prohibited RejectionReason = iota + 1 + ConnectionFailed + UnknownChannelType + ResourceShortage +) + +// String converts the rejection reason to human readable form. +func (r RejectionReason) String() string { + switch r { + case Prohibited: + return "administratively prohibited" + case ConnectionFailed: + return "connect failed" + case UnknownChannelType: + return "unknown channel type" + case ResourceShortage: + return "resource shortage" + } + return fmt.Sprintf("unknown reason %d", int(r)) +} + +func min(a uint32, b int) uint32 { + if a < uint32(b) { + return a + } + return uint32(b) +} + +type channelDirection uint8 + +const ( + channelInbound channelDirection = iota + channelOutbound +) + +// channel is an implementation of the Channel interface that works +// with the mux class. +type channel struct { + // R/O after creation + chanType string + extraData []byte + localId, remoteId uint32 + + // maxIncomingPayload and maxRemotePayload are the maximum + // payload sizes of normal and extended data packets for + // receiving and sending, respectively. The wire packet will + // be 9 or 13 bytes larger (excluding encryption overhead). + maxIncomingPayload uint32 + maxRemotePayload uint32 + + mux *mux + + // decided is set to true if an accept or reject message has been sent + // (for outbound channels) or received (for inbound channels). + decided bool + + // direction contains either channelOutbound, for channels created + // locally, or channelInbound, for channels created by the peer. + direction channelDirection + + // Pending internal channel messages. + msg chan interface{} + + // Since requests have no ID, there can be only one request + // with WantReply=true outstanding. This lock is held by a + // goroutine that has such an outgoing request pending. + sentRequestMu sync.Mutex + + incomingRequests chan *Request + + sentEOF bool + + // thread-safe data + remoteWin window + pending *buffer + extPending *buffer + + // windowMu protects myWindow, the flow-control window, and myConsumed, + // the number of bytes consumed since we last increased myWindow + windowMu sync.Mutex + myWindow uint32 + myConsumed uint32 + + // writeMu serializes calls to mux.conn.writePacket() and + // protects sentClose and packetPool. This mutex must be + // different from windowMu, as writePacket can block if there + // is a key exchange pending. + writeMu sync.Mutex + sentClose bool + + // packetPool has a buffer for each extended channel ID to + // save allocations during writes. + packetPool map[uint32][]byte +} + +// writePacket sends a packet. If the packet is a channel close, it updates +// sentClose. This method takes the lock c.writeMu. +func (ch *channel) writePacket(packet []byte) error { + ch.writeMu.Lock() + if ch.sentClose { + ch.writeMu.Unlock() + return io.EOF + } + ch.sentClose = (packet[0] == msgChannelClose) + err := ch.mux.conn.writePacket(packet) + ch.writeMu.Unlock() + return err +} + +func (ch *channel) sendMessage(msg interface{}) error { + if debugMux { + log.Printf("send(%d): %#v", ch.mux.chanList.offset, msg) + } + + p := Marshal(msg) + binary.BigEndian.PutUint32(p[1:], ch.remoteId) + return ch.writePacket(p) +} + +// WriteExtended writes data to a specific extended stream. These streams are +// used, for example, for stderr. +func (ch *channel) WriteExtended(data []byte, extendedCode uint32) (n int, err error) { + if ch.sentEOF { + return 0, io.EOF + } + // 1 byte message type, 4 bytes remoteId, 4 bytes data length + opCode := byte(msgChannelData) + headerLength := uint32(9) + if extendedCode > 0 { + headerLength += 4 + opCode = msgChannelExtendedData + } + + ch.writeMu.Lock() + packet := ch.packetPool[extendedCode] + // We don't remove the buffer from packetPool, so + // WriteExtended calls from different goroutines will be + // flagged as errors by the race detector. + ch.writeMu.Unlock() + + for len(data) > 0 { + space := min(ch.maxRemotePayload, len(data)) + if space, err = ch.remoteWin.reserve(space); err != nil { + return n, err + } + if want := headerLength + space; uint32(cap(packet)) < want { + packet = make([]byte, want) + } else { + packet = packet[:want] + } + + todo := data[:space] + + packet[0] = opCode + binary.BigEndian.PutUint32(packet[1:], ch.remoteId) + if extendedCode > 0 { + binary.BigEndian.PutUint32(packet[5:], uint32(extendedCode)) + } + binary.BigEndian.PutUint32(packet[headerLength-4:], uint32(len(todo))) + copy(packet[headerLength:], todo) + if err = ch.writePacket(packet); err != nil { + return n, err + } + + n += len(todo) + data = data[len(todo):] + } + + ch.writeMu.Lock() + ch.packetPool[extendedCode] = packet + ch.writeMu.Unlock() + + return n, err +} + +func (ch *channel) handleData(packet []byte) error { + headerLen := 9 + isExtendedData := packet[0] == msgChannelExtendedData + if isExtendedData { + headerLen = 13 + } + if len(packet) < headerLen { + // malformed data packet + return parseError(packet[0]) + } + + var extended uint32 + if isExtendedData { + extended = binary.BigEndian.Uint32(packet[5:]) + } + + length := binary.BigEndian.Uint32(packet[headerLen-4 : headerLen]) + if length == 0 { + return nil + } + if length > ch.maxIncomingPayload { + // TODO(hanwen): should send Disconnect? + return errors.New("ssh: incoming packet exceeds maximum payload size") + } + + data := packet[headerLen:] + if length != uint32(len(data)) { + return errors.New("ssh: wrong packet length") + } + + ch.windowMu.Lock() + if ch.myWindow < length { + ch.windowMu.Unlock() + // TODO(hanwen): should send Disconnect with reason? + return errors.New("ssh: remote side wrote too much") + } + ch.myWindow -= length + ch.windowMu.Unlock() + + if extended == 1 { + ch.extPending.write(data) + } else if extended > 0 { + // discard other extended data. + } else { + ch.pending.write(data) + } + return nil +} + +func (c *channel) adjustWindow(adj uint32) error { + c.windowMu.Lock() + // Since myConsumed and myWindow are managed on our side, and can never + // exceed the initial window setting, we don't worry about overflow. + c.myConsumed += adj + var sendAdj uint32 + if (channelWindowSize-c.myWindow > 3*c.maxIncomingPayload) || + (c.myWindow < channelWindowSize/2) { + sendAdj = c.myConsumed + c.myConsumed = 0 + c.myWindow += sendAdj + } + c.windowMu.Unlock() + if sendAdj == 0 { + return nil + } + return c.sendMessage(windowAdjustMsg{ + AdditionalBytes: sendAdj, + }) +} + +func (c *channel) ReadExtended(data []byte, extended uint32) (n int, err error) { + switch extended { + case 1: + n, err = c.extPending.Read(data) + case 0: + n, err = c.pending.Read(data) + default: + return 0, fmt.Errorf("ssh: extended code %d unimplemented", extended) + } + + if n > 0 { + err = c.adjustWindow(uint32(n)) + // sendWindowAdjust can return io.EOF if the remote + // peer has closed the connection, however we want to + // defer forwarding io.EOF to the caller of Read until + // the buffer has been drained. + if n > 0 && err == io.EOF { + err = nil + } + } + + return n, err +} + +func (c *channel) close() { + c.pending.eof() + c.extPending.eof() + close(c.msg) + close(c.incomingRequests) + c.writeMu.Lock() + // This is not necessary for a normal channel teardown, but if + // there was another error, it is. + c.sentClose = true + c.writeMu.Unlock() + // Unblock writers. + c.remoteWin.close() +} + +// responseMessageReceived is called when a success or failure message is +// received on a channel to check that such a message is reasonable for the +// given channel. +func (ch *channel) responseMessageReceived() error { + if ch.direction == channelInbound { + return errors.New("ssh: channel response message received on inbound channel") + } + if ch.decided { + return errors.New("ssh: duplicate response received for channel") + } + ch.decided = true + return nil +} + +func (ch *channel) handlePacket(packet []byte) error { + switch packet[0] { + case msgChannelData, msgChannelExtendedData: + return ch.handleData(packet) + case msgChannelClose: + ch.sendMessage(channelCloseMsg{PeersID: ch.remoteId}) + ch.mux.chanList.remove(ch.localId) + ch.close() + return nil + case msgChannelEOF: + // RFC 4254 is mute on how EOF affects dataExt messages but + // it is logical to signal EOF at the same time. + ch.extPending.eof() + ch.pending.eof() + return nil + } + + decoded, err := decode(packet) + if err != nil { + return err + } + + switch msg := decoded.(type) { + case *channelOpenFailureMsg: + if err := ch.responseMessageReceived(); err != nil { + return err + } + ch.mux.chanList.remove(msg.PeersID) + ch.msg <- msg + case *channelOpenConfirmMsg: + if err := ch.responseMessageReceived(); err != nil { + return err + } + if msg.MaxPacketSize < minPacketLength || msg.MaxPacketSize > 1<<31 { + return fmt.Errorf("ssh: invalid MaxPacketSize %d from peer", msg.MaxPacketSize) + } + ch.remoteId = msg.MyID + ch.maxRemotePayload = msg.MaxPacketSize + ch.remoteWin.add(msg.MyWindow) + ch.msg <- msg + case *windowAdjustMsg: + if !ch.remoteWin.add(msg.AdditionalBytes) { + return fmt.Errorf("ssh: invalid window update for %d bytes", msg.AdditionalBytes) + } + case *channelRequestMsg: + req := Request{ + Type: msg.Request, + WantReply: msg.WantReply, + Payload: msg.RequestSpecificData, + ch: ch, + } + + ch.incomingRequests <- &req + default: + ch.msg <- msg + } + return nil +} + +func (m *mux) newChannel(chanType string, direction channelDirection, extraData []byte) *channel { + ch := &channel{ + remoteWin: window{Cond: newCond()}, + myWindow: channelWindowSize, + pending: newBuffer(), + extPending: newBuffer(), + direction: direction, + incomingRequests: make(chan *Request, chanSize), + msg: make(chan interface{}, chanSize), + chanType: chanType, + extraData: extraData, + mux: m, + packetPool: make(map[uint32][]byte), + } + ch.localId = m.chanList.add(ch) + return ch +} + +var errUndecided = errors.New("ssh: must Accept or Reject channel") +var errDecidedAlready = errors.New("ssh: can call Accept or Reject only once") + +type extChannel struct { + code uint32 + ch *channel +} + +func (e *extChannel) Write(data []byte) (n int, err error) { + return e.ch.WriteExtended(data, e.code) +} + +func (e *extChannel) Read(data []byte) (n int, err error) { + return e.ch.ReadExtended(data, e.code) +} + +func (ch *channel) Accept() (Channel, <-chan *Request, error) { + if ch.decided { + return nil, nil, errDecidedAlready + } + ch.maxIncomingPayload = channelMaxPacket + confirm := channelOpenConfirmMsg{ + PeersID: ch.remoteId, + MyID: ch.localId, + MyWindow: ch.myWindow, + MaxPacketSize: ch.maxIncomingPayload, + } + ch.decided = true + if err := ch.sendMessage(confirm); err != nil { + return nil, nil, err + } + + return ch, ch.incomingRequests, nil +} + +func (ch *channel) Reject(reason RejectionReason, message string) error { + if ch.decided { + return errDecidedAlready + } + reject := channelOpenFailureMsg{ + PeersID: ch.remoteId, + Reason: reason, + Message: message, + Language: "en", + } + ch.decided = true + return ch.sendMessage(reject) +} + +func (ch *channel) Read(data []byte) (int, error) { + if !ch.decided { + return 0, errUndecided + } + return ch.ReadExtended(data, 0) +} + +func (ch *channel) Write(data []byte) (int, error) { + if !ch.decided { + return 0, errUndecided + } + return ch.WriteExtended(data, 0) +} + +func (ch *channel) CloseWrite() error { + if !ch.decided { + return errUndecided + } + ch.sentEOF = true + return ch.sendMessage(channelEOFMsg{ + PeersID: ch.remoteId}) +} + +func (ch *channel) Close() error { + if !ch.decided { + return errUndecided + } + + return ch.sendMessage(channelCloseMsg{ + PeersID: ch.remoteId}) +} + +// Extended returns an io.ReadWriter that sends and receives data on the given, +// SSH extended stream. Such streams are used, for example, for stderr. +func (ch *channel) Extended(code uint32) io.ReadWriter { + if !ch.decided { + return nil + } + return &extChannel{code, ch} +} + +func (ch *channel) Stderr() io.ReadWriter { + return ch.Extended(1) +} + +func (ch *channel) SendRequest(name string, wantReply bool, payload []byte) (bool, error) { + if !ch.decided { + return false, errUndecided + } + + if wantReply { + ch.sentRequestMu.Lock() + defer ch.sentRequestMu.Unlock() + } + + msg := channelRequestMsg{ + PeersID: ch.remoteId, + Request: name, + WantReply: wantReply, + RequestSpecificData: payload, + } + + if err := ch.sendMessage(msg); err != nil { + return false, err + } + + if wantReply { + m, ok := (<-ch.msg) + if !ok { + return false, io.EOF + } + switch m.(type) { + case *channelRequestFailureMsg: + return false, nil + case *channelRequestSuccessMsg: + return true, nil + default: + return false, fmt.Errorf("ssh: unexpected response to channel request: %#v", m) + } + } + + return false, nil +} + +// ackRequest either sends an ack or nack to the channel request. +func (ch *channel) ackRequest(ok bool) error { + if !ch.decided { + return errUndecided + } + + var msg interface{} + if !ok { + msg = channelRequestFailureMsg{ + PeersID: ch.remoteId, + } + } else { + msg = channelRequestSuccessMsg{ + PeersID: ch.remoteId, + } + } + return ch.sendMessage(msg) +} + +func (ch *channel) ChannelType() string { + return ch.chanType +} + +func (ch *channel) ExtraData() []byte { + return ch.extraData +} diff --git a/tempfork/sshtest/ssh/cipher.go b/tempfork/sshtest/ssh/cipher.go new file mode 100644 index 000000000..0533786f4 --- /dev/null +++ b/tempfork/sshtest/ssh/cipher.go @@ -0,0 +1,789 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "crypto/aes" + "crypto/cipher" + "crypto/des" + "crypto/rc4" + "crypto/subtle" + "encoding/binary" + "errors" + "fmt" + "hash" + "io" + + "golang.org/x/crypto/chacha20" + "golang.org/x/crypto/poly1305" +) + +const ( + packetSizeMultiple = 16 // TODO(huin) this should be determined by the cipher. + + // RFC 4253 section 6.1 defines a minimum packet size of 32768 that implementations + // MUST be able to process (plus a few more kilobytes for padding and mac). The RFC + // indicates implementations SHOULD be able to handle larger packet sizes, but then + // waffles on about reasonable limits. + // + // OpenSSH caps their maxPacket at 256kB so we choose to do + // the same. maxPacket is also used to ensure that uint32 + // length fields do not overflow, so it should remain well + // below 4G. + maxPacket = 256 * 1024 +) + +// noneCipher implements cipher.Stream and provides no encryption. It is used +// by the transport before the first key-exchange. +type noneCipher struct{} + +func (c noneCipher) XORKeyStream(dst, src []byte) { + copy(dst, src) +} + +func newAESCTR(key, iv []byte) (cipher.Stream, error) { + c, err := aes.NewCipher(key) + if err != nil { + return nil, err + } + return cipher.NewCTR(c, iv), nil +} + +func newRC4(key, iv []byte) (cipher.Stream, error) { + return rc4.NewCipher(key) +} + +type cipherMode struct { + keySize int + ivSize int + create func(key, iv []byte, macKey []byte, algs directionAlgorithms) (packetCipher, error) +} + +func streamCipherMode(skip int, createFunc func(key, iv []byte) (cipher.Stream, error)) func(key, iv []byte, macKey []byte, algs directionAlgorithms) (packetCipher, error) { + return func(key, iv, macKey []byte, algs directionAlgorithms) (packetCipher, error) { + stream, err := createFunc(key, iv) + if err != nil { + return nil, err + } + + var streamDump []byte + if skip > 0 { + streamDump = make([]byte, 512) + } + + for remainingToDump := skip; remainingToDump > 0; { + dumpThisTime := remainingToDump + if dumpThisTime > len(streamDump) { + dumpThisTime = len(streamDump) + } + stream.XORKeyStream(streamDump[:dumpThisTime], streamDump[:dumpThisTime]) + remainingToDump -= dumpThisTime + } + + mac := macModes[algs.MAC].new(macKey) + return &streamPacketCipher{ + mac: mac, + etm: macModes[algs.MAC].etm, + macResult: make([]byte, mac.Size()), + cipher: stream, + }, nil + } +} + +// cipherModes documents properties of supported ciphers. Ciphers not included +// are not supported and will not be negotiated, even if explicitly requested in +// ClientConfig.Crypto.Ciphers. +var cipherModes = map[string]*cipherMode{ + // Ciphers from RFC 4344, which introduced many CTR-based ciphers. Algorithms + // are defined in the order specified in the RFC. + "aes128-ctr": {16, aes.BlockSize, streamCipherMode(0, newAESCTR)}, + "aes192-ctr": {24, aes.BlockSize, streamCipherMode(0, newAESCTR)}, + "aes256-ctr": {32, aes.BlockSize, streamCipherMode(0, newAESCTR)}, + + // Ciphers from RFC 4345, which introduces security-improved arcfour ciphers. + // They are defined in the order specified in the RFC. + "arcfour128": {16, 0, streamCipherMode(1536, newRC4)}, + "arcfour256": {32, 0, streamCipherMode(1536, newRC4)}, + + // Cipher defined in RFC 4253, which describes SSH Transport Layer Protocol. + // Note that this cipher is not safe, as stated in RFC 4253: "Arcfour (and + // RC4) has problems with weak keys, and should be used with caution." + // RFC 4345 introduces improved versions of Arcfour. + "arcfour": {16, 0, streamCipherMode(0, newRC4)}, + + // AEAD ciphers + gcm128CipherID: {16, 12, newGCMCipher}, + gcm256CipherID: {32, 12, newGCMCipher}, + chacha20Poly1305ID: {64, 0, newChaCha20Cipher}, + + // CBC mode is insecure and so is not included in the default config. + // (See https://www.ieee-security.org/TC/SP2013/papers/4977a526.pdf). If absolutely + // needed, it's possible to specify a custom Config to enable it. + // You should expect that an active attacker can recover plaintext if + // you do. + aes128cbcID: {16, aes.BlockSize, newAESCBCCipher}, + + // 3des-cbc is insecure and is not included in the default + // config. + tripledescbcID: {24, des.BlockSize, newTripleDESCBCCipher}, +} + +// prefixLen is the length of the packet prefix that contains the packet length +// and number of padding bytes. +const prefixLen = 5 + +// streamPacketCipher is a packetCipher using a stream cipher. +type streamPacketCipher struct { + mac hash.Hash + cipher cipher.Stream + etm bool + + // The following members are to avoid per-packet allocations. + prefix [prefixLen]byte + seqNumBytes [4]byte + padding [2 * packetSizeMultiple]byte + packetData []byte + macResult []byte +} + +// readCipherPacket reads and decrypt a single packet from the reader argument. +func (s *streamPacketCipher) readCipherPacket(seqNum uint32, r io.Reader) ([]byte, error) { + if _, err := io.ReadFull(r, s.prefix[:]); err != nil { + return nil, err + } + + var encryptedPaddingLength [1]byte + if s.mac != nil && s.etm { + copy(encryptedPaddingLength[:], s.prefix[4:5]) + s.cipher.XORKeyStream(s.prefix[4:5], s.prefix[4:5]) + } else { + s.cipher.XORKeyStream(s.prefix[:], s.prefix[:]) + } + + length := binary.BigEndian.Uint32(s.prefix[0:4]) + paddingLength := uint32(s.prefix[4]) + + var macSize uint32 + if s.mac != nil { + s.mac.Reset() + binary.BigEndian.PutUint32(s.seqNumBytes[:], seqNum) + s.mac.Write(s.seqNumBytes[:]) + if s.etm { + s.mac.Write(s.prefix[:4]) + s.mac.Write(encryptedPaddingLength[:]) + } else { + s.mac.Write(s.prefix[:]) + } + macSize = uint32(s.mac.Size()) + } + + if length <= paddingLength+1 { + return nil, errors.New("ssh: invalid packet length, packet too small") + } + + if length > maxPacket { + return nil, errors.New("ssh: invalid packet length, packet too large") + } + + // the maxPacket check above ensures that length-1+macSize + // does not overflow. + if uint32(cap(s.packetData)) < length-1+macSize { + s.packetData = make([]byte, length-1+macSize) + } else { + s.packetData = s.packetData[:length-1+macSize] + } + + if _, err := io.ReadFull(r, s.packetData); err != nil { + return nil, err + } + mac := s.packetData[length-1:] + data := s.packetData[:length-1] + + if s.mac != nil && s.etm { + s.mac.Write(data) + } + + s.cipher.XORKeyStream(data, data) + + if s.mac != nil { + if !s.etm { + s.mac.Write(data) + } + s.macResult = s.mac.Sum(s.macResult[:0]) + if subtle.ConstantTimeCompare(s.macResult, mac) != 1 { + return nil, errors.New("ssh: MAC failure") + } + } + + return s.packetData[:length-paddingLength-1], nil +} + +// writeCipherPacket encrypts and sends a packet of data to the writer argument +func (s *streamPacketCipher) writeCipherPacket(seqNum uint32, w io.Writer, rand io.Reader, packet []byte) error { + if len(packet) > maxPacket { + return errors.New("ssh: packet too large") + } + + aadlen := 0 + if s.mac != nil && s.etm { + // packet length is not encrypted for EtM modes + aadlen = 4 + } + + paddingLength := packetSizeMultiple - (prefixLen+len(packet)-aadlen)%packetSizeMultiple + if paddingLength < 4 { + paddingLength += packetSizeMultiple + } + + length := len(packet) + 1 + paddingLength + binary.BigEndian.PutUint32(s.prefix[:], uint32(length)) + s.prefix[4] = byte(paddingLength) + padding := s.padding[:paddingLength] + if _, err := io.ReadFull(rand, padding); err != nil { + return err + } + + if s.mac != nil { + s.mac.Reset() + binary.BigEndian.PutUint32(s.seqNumBytes[:], seqNum) + s.mac.Write(s.seqNumBytes[:]) + + if s.etm { + // For EtM algorithms, the packet length must stay unencrypted, + // but the following data (padding length) must be encrypted + s.cipher.XORKeyStream(s.prefix[4:5], s.prefix[4:5]) + } + + s.mac.Write(s.prefix[:]) + + if !s.etm { + // For non-EtM algorithms, the algorithm is applied on unencrypted data + s.mac.Write(packet) + s.mac.Write(padding) + } + } + + if !(s.mac != nil && s.etm) { + // For EtM algorithms, the padding length has already been encrypted + // and the packet length must remain unencrypted + s.cipher.XORKeyStream(s.prefix[:], s.prefix[:]) + } + + s.cipher.XORKeyStream(packet, packet) + s.cipher.XORKeyStream(padding, padding) + + if s.mac != nil && s.etm { + // For EtM algorithms, packet and padding must be encrypted + s.mac.Write(packet) + s.mac.Write(padding) + } + + if _, err := w.Write(s.prefix[:]); err != nil { + return err + } + if _, err := w.Write(packet); err != nil { + return err + } + if _, err := w.Write(padding); err != nil { + return err + } + + if s.mac != nil { + s.macResult = s.mac.Sum(s.macResult[:0]) + if _, err := w.Write(s.macResult); err != nil { + return err + } + } + + return nil +} + +type gcmCipher struct { + aead cipher.AEAD + prefix [4]byte + iv []byte + buf []byte +} + +func newGCMCipher(key, iv, unusedMacKey []byte, unusedAlgs directionAlgorithms) (packetCipher, error) { + c, err := aes.NewCipher(key) + if err != nil { + return nil, err + } + + aead, err := cipher.NewGCM(c) + if err != nil { + return nil, err + } + + return &gcmCipher{ + aead: aead, + iv: iv, + }, nil +} + +const gcmTagSize = 16 + +func (c *gcmCipher) writeCipherPacket(seqNum uint32, w io.Writer, rand io.Reader, packet []byte) error { + // Pad out to multiple of 16 bytes. This is different from the + // stream cipher because that encrypts the length too. + padding := byte(packetSizeMultiple - (1+len(packet))%packetSizeMultiple) + if padding < 4 { + padding += packetSizeMultiple + } + + length := uint32(len(packet) + int(padding) + 1) + binary.BigEndian.PutUint32(c.prefix[:], length) + if _, err := w.Write(c.prefix[:]); err != nil { + return err + } + + if cap(c.buf) < int(length) { + c.buf = make([]byte, length) + } else { + c.buf = c.buf[:length] + } + + c.buf[0] = padding + copy(c.buf[1:], packet) + if _, err := io.ReadFull(rand, c.buf[1+len(packet):]); err != nil { + return err + } + c.buf = c.aead.Seal(c.buf[:0], c.iv, c.buf, c.prefix[:]) + if _, err := w.Write(c.buf); err != nil { + return err + } + c.incIV() + + return nil +} + +func (c *gcmCipher) incIV() { + for i := 4 + 7; i >= 4; i-- { + c.iv[i]++ + if c.iv[i] != 0 { + break + } + } +} + +func (c *gcmCipher) readCipherPacket(seqNum uint32, r io.Reader) ([]byte, error) { + if _, err := io.ReadFull(r, c.prefix[:]); err != nil { + return nil, err + } + length := binary.BigEndian.Uint32(c.prefix[:]) + if length > maxPacket { + return nil, errors.New("ssh: max packet length exceeded") + } + + if cap(c.buf) < int(length+gcmTagSize) { + c.buf = make([]byte, length+gcmTagSize) + } else { + c.buf = c.buf[:length+gcmTagSize] + } + + if _, err := io.ReadFull(r, c.buf); err != nil { + return nil, err + } + + plain, err := c.aead.Open(c.buf[:0], c.iv, c.buf, c.prefix[:]) + if err != nil { + return nil, err + } + c.incIV() + + if len(plain) == 0 { + return nil, errors.New("ssh: empty packet") + } + + padding := plain[0] + if padding < 4 { + // padding is a byte, so it automatically satisfies + // the maximum size, which is 255. + return nil, fmt.Errorf("ssh: illegal padding %d", padding) + } + + if int(padding+1) >= len(plain) { + return nil, fmt.Errorf("ssh: padding %d too large", padding) + } + plain = plain[1 : length-uint32(padding)] + return plain, nil +} + +// cbcCipher implements aes128-cbc cipher defined in RFC 4253 section 6.1 +type cbcCipher struct { + mac hash.Hash + macSize uint32 + decrypter cipher.BlockMode + encrypter cipher.BlockMode + + // The following members are to avoid per-packet allocations. + seqNumBytes [4]byte + packetData []byte + macResult []byte + + // Amount of data we should still read to hide which + // verification error triggered. + oracleCamouflage uint32 +} + +func newCBCCipher(c cipher.Block, key, iv, macKey []byte, algs directionAlgorithms) (packetCipher, error) { + cbc := &cbcCipher{ + mac: macModes[algs.MAC].new(macKey), + decrypter: cipher.NewCBCDecrypter(c, iv), + encrypter: cipher.NewCBCEncrypter(c, iv), + packetData: make([]byte, 1024), + } + if cbc.mac != nil { + cbc.macSize = uint32(cbc.mac.Size()) + } + + return cbc, nil +} + +func newAESCBCCipher(key, iv, macKey []byte, algs directionAlgorithms) (packetCipher, error) { + c, err := aes.NewCipher(key) + if err != nil { + return nil, err + } + + cbc, err := newCBCCipher(c, key, iv, macKey, algs) + if err != nil { + return nil, err + } + + return cbc, nil +} + +func newTripleDESCBCCipher(key, iv, macKey []byte, algs directionAlgorithms) (packetCipher, error) { + c, err := des.NewTripleDESCipher(key) + if err != nil { + return nil, err + } + + cbc, err := newCBCCipher(c, key, iv, macKey, algs) + if err != nil { + return nil, err + } + + return cbc, nil +} + +func maxUInt32(a, b int) uint32 { + if a > b { + return uint32(a) + } + return uint32(b) +} + +const ( + cbcMinPacketSizeMultiple = 8 + cbcMinPacketSize = 16 + cbcMinPaddingSize = 4 +) + +// cbcError represents a verification error that may leak information. +type cbcError string + +func (e cbcError) Error() string { return string(e) } + +func (c *cbcCipher) readCipherPacket(seqNum uint32, r io.Reader) ([]byte, error) { + p, err := c.readCipherPacketLeaky(seqNum, r) + if err != nil { + if _, ok := err.(cbcError); ok { + // Verification error: read a fixed amount of + // data, to make distinguishing between + // failing MAC and failing length check more + // difficult. + io.CopyN(io.Discard, r, int64(c.oracleCamouflage)) + } + } + return p, err +} + +func (c *cbcCipher) readCipherPacketLeaky(seqNum uint32, r io.Reader) ([]byte, error) { + blockSize := c.decrypter.BlockSize() + + // Read the header, which will include some of the subsequent data in the + // case of block ciphers - this is copied back to the payload later. + // How many bytes of payload/padding will be read with this first read. + firstBlockLength := uint32((prefixLen + blockSize - 1) / blockSize * blockSize) + firstBlock := c.packetData[:firstBlockLength] + if _, err := io.ReadFull(r, firstBlock); err != nil { + return nil, err + } + + c.oracleCamouflage = maxPacket + 4 + c.macSize - firstBlockLength + + c.decrypter.CryptBlocks(firstBlock, firstBlock) + length := binary.BigEndian.Uint32(firstBlock[:4]) + if length > maxPacket { + return nil, cbcError("ssh: packet too large") + } + if length+4 < maxUInt32(cbcMinPacketSize, blockSize) { + // The minimum size of a packet is 16 (or the cipher block size, whichever + // is larger) bytes. + return nil, cbcError("ssh: packet too small") + } + // The length of the packet (including the length field but not the MAC) must + // be a multiple of the block size or 8, whichever is larger. + if (length+4)%maxUInt32(cbcMinPacketSizeMultiple, blockSize) != 0 { + return nil, cbcError("ssh: invalid packet length multiple") + } + + paddingLength := uint32(firstBlock[4]) + if paddingLength < cbcMinPaddingSize || length <= paddingLength+1 { + return nil, cbcError("ssh: invalid packet length") + } + + // Positions within the c.packetData buffer: + macStart := 4 + length + paddingStart := macStart - paddingLength + + // Entire packet size, starting before length, ending at end of mac. + entirePacketSize := macStart + c.macSize + + // Ensure c.packetData is large enough for the entire packet data. + if uint32(cap(c.packetData)) < entirePacketSize { + // Still need to upsize and copy, but this should be rare at runtime, only + // on upsizing the packetData buffer. + c.packetData = make([]byte, entirePacketSize) + copy(c.packetData, firstBlock) + } else { + c.packetData = c.packetData[:entirePacketSize] + } + + n, err := io.ReadFull(r, c.packetData[firstBlockLength:]) + if err != nil { + return nil, err + } + c.oracleCamouflage -= uint32(n) + + remainingCrypted := c.packetData[firstBlockLength:macStart] + c.decrypter.CryptBlocks(remainingCrypted, remainingCrypted) + + mac := c.packetData[macStart:] + if c.mac != nil { + c.mac.Reset() + binary.BigEndian.PutUint32(c.seqNumBytes[:], seqNum) + c.mac.Write(c.seqNumBytes[:]) + c.mac.Write(c.packetData[:macStart]) + c.macResult = c.mac.Sum(c.macResult[:0]) + if subtle.ConstantTimeCompare(c.macResult, mac) != 1 { + return nil, cbcError("ssh: MAC failure") + } + } + + return c.packetData[prefixLen:paddingStart], nil +} + +func (c *cbcCipher) writeCipherPacket(seqNum uint32, w io.Writer, rand io.Reader, packet []byte) error { + effectiveBlockSize := maxUInt32(cbcMinPacketSizeMultiple, c.encrypter.BlockSize()) + + // Length of encrypted portion of the packet (header, payload, padding). + // Enforce minimum padding and packet size. + encLength := maxUInt32(prefixLen+len(packet)+cbcMinPaddingSize, cbcMinPaddingSize) + // Enforce block size. + encLength = (encLength + effectiveBlockSize - 1) / effectiveBlockSize * effectiveBlockSize + + length := encLength - 4 + paddingLength := int(length) - (1 + len(packet)) + + // Overall buffer contains: header, payload, padding, mac. + // Space for the MAC is reserved in the capacity but not the slice length. + bufferSize := encLength + c.macSize + if uint32(cap(c.packetData)) < bufferSize { + c.packetData = make([]byte, encLength, bufferSize) + } else { + c.packetData = c.packetData[:encLength] + } + + p := c.packetData + + // Packet header. + binary.BigEndian.PutUint32(p, length) + p = p[4:] + p[0] = byte(paddingLength) + + // Payload. + p = p[1:] + copy(p, packet) + + // Padding. + p = p[len(packet):] + if _, err := io.ReadFull(rand, p); err != nil { + return err + } + + if c.mac != nil { + c.mac.Reset() + binary.BigEndian.PutUint32(c.seqNumBytes[:], seqNum) + c.mac.Write(c.seqNumBytes[:]) + c.mac.Write(c.packetData) + // The MAC is now appended into the capacity reserved for it earlier. + c.packetData = c.mac.Sum(c.packetData) + } + + c.encrypter.CryptBlocks(c.packetData[:encLength], c.packetData[:encLength]) + + if _, err := w.Write(c.packetData); err != nil { + return err + } + + return nil +} + +const chacha20Poly1305ID = "chacha20-poly1305@openssh.com" + +// chacha20Poly1305Cipher implements the chacha20-poly1305@openssh.com +// AEAD, which is described here: +// +// https://tools.ietf.org/html/draft-josefsson-ssh-chacha20-poly1305-openssh-00 +// +// the methods here also implement padding, which RFC 4253 Section 6 +// also requires of stream ciphers. +type chacha20Poly1305Cipher struct { + lengthKey [32]byte + contentKey [32]byte + buf []byte +} + +func newChaCha20Cipher(key, unusedIV, unusedMACKey []byte, unusedAlgs directionAlgorithms) (packetCipher, error) { + if len(key) != 64 { + panic(len(key)) + } + + c := &chacha20Poly1305Cipher{ + buf: make([]byte, 256), + } + + copy(c.contentKey[:], key[:32]) + copy(c.lengthKey[:], key[32:]) + return c, nil +} + +func (c *chacha20Poly1305Cipher) readCipherPacket(seqNum uint32, r io.Reader) ([]byte, error) { + nonce := make([]byte, 12) + binary.BigEndian.PutUint32(nonce[8:], seqNum) + s, err := chacha20.NewUnauthenticatedCipher(c.contentKey[:], nonce) + if err != nil { + return nil, err + } + var polyKey, discardBuf [32]byte + s.XORKeyStream(polyKey[:], polyKey[:]) + s.XORKeyStream(discardBuf[:], discardBuf[:]) // skip the next 32 bytes + + encryptedLength := c.buf[:4] + if _, err := io.ReadFull(r, encryptedLength); err != nil { + return nil, err + } + + var lenBytes [4]byte + ls, err := chacha20.NewUnauthenticatedCipher(c.lengthKey[:], nonce) + if err != nil { + return nil, err + } + ls.XORKeyStream(lenBytes[:], encryptedLength) + + length := binary.BigEndian.Uint32(lenBytes[:]) + if length > maxPacket { + return nil, errors.New("ssh: invalid packet length, packet too large") + } + + contentEnd := 4 + length + packetEnd := contentEnd + poly1305.TagSize + if uint32(cap(c.buf)) < packetEnd { + c.buf = make([]byte, packetEnd) + copy(c.buf[:], encryptedLength) + } else { + c.buf = c.buf[:packetEnd] + } + + if _, err := io.ReadFull(r, c.buf[4:packetEnd]); err != nil { + return nil, err + } + + var mac [poly1305.TagSize]byte + copy(mac[:], c.buf[contentEnd:packetEnd]) + if !poly1305.Verify(&mac, c.buf[:contentEnd], &polyKey) { + return nil, errors.New("ssh: MAC failure") + } + + plain := c.buf[4:contentEnd] + s.XORKeyStream(plain, plain) + + if len(plain) == 0 { + return nil, errors.New("ssh: empty packet") + } + + padding := plain[0] + if padding < 4 { + // padding is a byte, so it automatically satisfies + // the maximum size, which is 255. + return nil, fmt.Errorf("ssh: illegal padding %d", padding) + } + + if int(padding)+1 >= len(plain) { + return nil, fmt.Errorf("ssh: padding %d too large", padding) + } + + plain = plain[1 : len(plain)-int(padding)] + + return plain, nil +} + +func (c *chacha20Poly1305Cipher) writeCipherPacket(seqNum uint32, w io.Writer, rand io.Reader, payload []byte) error { + nonce := make([]byte, 12) + binary.BigEndian.PutUint32(nonce[8:], seqNum) + s, err := chacha20.NewUnauthenticatedCipher(c.contentKey[:], nonce) + if err != nil { + return err + } + var polyKey, discardBuf [32]byte + s.XORKeyStream(polyKey[:], polyKey[:]) + s.XORKeyStream(discardBuf[:], discardBuf[:]) // skip the next 32 bytes + + // There is no blocksize, so fall back to multiple of 8 byte + // padding, as described in RFC 4253, Sec 6. + const packetSizeMultiple = 8 + + padding := packetSizeMultiple - (1+len(payload))%packetSizeMultiple + if padding < 4 { + padding += packetSizeMultiple + } + + // size (4 bytes), padding (1), payload, padding, tag. + totalLength := 4 + 1 + len(payload) + padding + poly1305.TagSize + if cap(c.buf) < totalLength { + c.buf = make([]byte, totalLength) + } else { + c.buf = c.buf[:totalLength] + } + + binary.BigEndian.PutUint32(c.buf, uint32(1+len(payload)+padding)) + ls, err := chacha20.NewUnauthenticatedCipher(c.lengthKey[:], nonce) + if err != nil { + return err + } + ls.XORKeyStream(c.buf, c.buf[:4]) + c.buf[4] = byte(padding) + copy(c.buf[5:], payload) + packetEnd := 5 + len(payload) + padding + if _, err := io.ReadFull(rand, c.buf[5+len(payload):packetEnd]); err != nil { + return err + } + + s.XORKeyStream(c.buf[4:], c.buf[4:packetEnd]) + + var mac [poly1305.TagSize]byte + poly1305.Sum(&mac, c.buf[:packetEnd], &polyKey) + + copy(c.buf[packetEnd:], mac[:]) + + if _, err := w.Write(c.buf); err != nil { + return err + } + return nil +} diff --git a/tempfork/sshtest/ssh/cipher_test.go b/tempfork/sshtest/ssh/cipher_test.go new file mode 100644 index 000000000..fe339862c --- /dev/null +++ b/tempfork/sshtest/ssh/cipher_test.go @@ -0,0 +1,231 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "bytes" + "crypto" + "crypto/rand" + "encoding/binary" + "io" + "testing" + + "golang.org/x/crypto/chacha20" + "golang.org/x/crypto/poly1305" +) + +func TestDefaultCiphersExist(t *testing.T) { + for _, cipherAlgo := range supportedCiphers { + if _, ok := cipherModes[cipherAlgo]; !ok { + t.Errorf("supported cipher %q is unknown", cipherAlgo) + } + } + for _, cipherAlgo := range preferredCiphers { + if _, ok := cipherModes[cipherAlgo]; !ok { + t.Errorf("preferred cipher %q is unknown", cipherAlgo) + } + } +} + +func TestPacketCiphers(t *testing.T) { + defaultMac := "hmac-sha2-256" + defaultCipher := "aes128-ctr" + for cipher := range cipherModes { + t.Run("cipher="+cipher, + func(t *testing.T) { testPacketCipher(t, cipher, defaultMac) }) + } + for mac := range macModes { + t.Run("mac="+mac, + func(t *testing.T) { testPacketCipher(t, defaultCipher, mac) }) + } +} + +func testPacketCipher(t *testing.T, cipher, mac string) { + kr := &kexResult{Hash: crypto.SHA1} + algs := directionAlgorithms{ + Cipher: cipher, + MAC: mac, + Compression: "none", + } + client, err := newPacketCipher(clientKeys, algs, kr) + if err != nil { + t.Fatalf("newPacketCipher(client, %q, %q): %v", cipher, mac, err) + } + server, err := newPacketCipher(clientKeys, algs, kr) + if err != nil { + t.Fatalf("newPacketCipher(client, %q, %q): %v", cipher, mac, err) + } + + want := "bla bla" + input := []byte(want) + buf := &bytes.Buffer{} + if err := client.writeCipherPacket(0, buf, rand.Reader, input); err != nil { + t.Fatalf("writeCipherPacket(%q, %q): %v", cipher, mac, err) + } + + packet, err := server.readCipherPacket(0, buf) + if err != nil { + t.Fatalf("readCipherPacket(%q, %q): %v", cipher, mac, err) + } + + if string(packet) != want { + t.Errorf("roundtrip(%q, %q): got %q, want %q", cipher, mac, packet, want) + } +} + +func TestCBCOracleCounterMeasure(t *testing.T) { + kr := &kexResult{Hash: crypto.SHA1} + algs := directionAlgorithms{ + Cipher: aes128cbcID, + MAC: "hmac-sha1", + Compression: "none", + } + client, err := newPacketCipher(clientKeys, algs, kr) + if err != nil { + t.Fatalf("newPacketCipher(client): %v", err) + } + + want := "bla bla" + input := []byte(want) + buf := &bytes.Buffer{} + if err := client.writeCipherPacket(0, buf, rand.Reader, input); err != nil { + t.Errorf("writeCipherPacket: %v", err) + } + + packetSize := buf.Len() + buf.Write(make([]byte, 2*maxPacket)) + + // We corrupt each byte, but this usually will only test the + // 'packet too large' or 'MAC failure' cases. + lastRead := -1 + for i := 0; i < packetSize; i++ { + server, err := newPacketCipher(clientKeys, algs, kr) + if err != nil { + t.Fatalf("newPacketCipher(client): %v", err) + } + + fresh := &bytes.Buffer{} + fresh.Write(buf.Bytes()) + fresh.Bytes()[i] ^= 0x01 + + before := fresh.Len() + _, err = server.readCipherPacket(0, fresh) + if err == nil { + t.Errorf("corrupt byte %d: readCipherPacket succeeded ", i) + continue + } + if _, ok := err.(cbcError); !ok { + t.Errorf("corrupt byte %d: got %v (%T), want cbcError", i, err, err) + continue + } + + after := fresh.Len() + bytesRead := before - after + if bytesRead < maxPacket { + t.Errorf("corrupt byte %d: read %d bytes, want more than %d", i, bytesRead, maxPacket) + continue + } + + if i > 0 && bytesRead != lastRead { + t.Errorf("corrupt byte %d: read %d bytes, want %d bytes read", i, bytesRead, lastRead) + } + lastRead = bytesRead + } +} + +func TestCVE202143565(t *testing.T) { + tests := []struct { + cipher string + constructPacket func(packetCipher) io.Reader + }{ + { + cipher: gcm128CipherID, + constructPacket: func(client packetCipher) io.Reader { + internalCipher := client.(*gcmCipher) + b := &bytes.Buffer{} + prefix := [4]byte{} + if _, err := b.Write(prefix[:]); err != nil { + t.Fatal(err) + } + internalCipher.buf = internalCipher.aead.Seal(internalCipher.buf[:0], internalCipher.iv, []byte{}, prefix[:]) + if _, err := b.Write(internalCipher.buf); err != nil { + t.Fatal(err) + } + internalCipher.incIV() + + return b + }, + }, + { + cipher: chacha20Poly1305ID, + constructPacket: func(client packetCipher) io.Reader { + internalCipher := client.(*chacha20Poly1305Cipher) + b := &bytes.Buffer{} + + nonce := make([]byte, 12) + s, err := chacha20.NewUnauthenticatedCipher(internalCipher.contentKey[:], nonce) + if err != nil { + t.Fatal(err) + } + var polyKey, discardBuf [32]byte + s.XORKeyStream(polyKey[:], polyKey[:]) + s.XORKeyStream(discardBuf[:], discardBuf[:]) // skip the next 32 bytes + + internalCipher.buf = make([]byte, 4+poly1305.TagSize) + binary.BigEndian.PutUint32(internalCipher.buf, 0) + ls, err := chacha20.NewUnauthenticatedCipher(internalCipher.lengthKey[:], nonce) + if err != nil { + t.Fatal(err) + } + ls.XORKeyStream(internalCipher.buf, internalCipher.buf[:4]) + if _, err := io.ReadFull(rand.Reader, internalCipher.buf[4:4]); err != nil { + t.Fatal(err) + } + + s.XORKeyStream(internalCipher.buf[4:], internalCipher.buf[4:4]) + + var tag [poly1305.TagSize]byte + poly1305.Sum(&tag, internalCipher.buf[:4], &polyKey) + + copy(internalCipher.buf[4:], tag[:]) + + if _, err := b.Write(internalCipher.buf); err != nil { + t.Fatal(err) + } + + return b + }, + }, + } + + for _, tc := range tests { + mac := "hmac-sha2-256" + + kr := &kexResult{Hash: crypto.SHA1} + algs := directionAlgorithms{ + Cipher: tc.cipher, + MAC: mac, + Compression: "none", + } + client, err := newPacketCipher(clientKeys, algs, kr) + if err != nil { + t.Fatalf("newPacketCipher(client, %q, %q): %v", tc.cipher, mac, err) + } + server, err := newPacketCipher(clientKeys, algs, kr) + if err != nil { + t.Fatalf("newPacketCipher(client, %q, %q): %v", tc.cipher, mac, err) + } + + b := tc.constructPacket(client) + + wantErr := "ssh: empty packet" + _, err = server.readCipherPacket(0, b) + if err == nil { + t.Fatalf("readCipherPacket(%q, %q): didn't fail with empty packet", tc.cipher, mac) + } else if err.Error() != wantErr { + t.Fatalf("readCipherPacket(%q, %q): unexpected error, got %q, want %q", tc.cipher, mac, err, wantErr) + } + } +} diff --git a/tempfork/sshtest/ssh/client.go b/tempfork/sshtest/ssh/client.go new file mode 100644 index 000000000..fd8c49749 --- /dev/null +++ b/tempfork/sshtest/ssh/client.go @@ -0,0 +1,282 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "bytes" + "errors" + "fmt" + "net" + "os" + "sync" + "time" +) + +// Client implements a traditional SSH client that supports shells, +// subprocesses, TCP port/streamlocal forwarding and tunneled dialing. +type Client struct { + Conn + + handleForwardsOnce sync.Once // guards calling (*Client).handleForwards + + forwards forwardList // forwarded tcpip connections from the remote side + mu sync.Mutex + channelHandlers map[string]chan NewChannel +} + +// HandleChannelOpen returns a channel on which NewChannel requests +// for the given type are sent. If the type already is being handled, +// nil is returned. The channel is closed when the connection is closed. +func (c *Client) HandleChannelOpen(channelType string) <-chan NewChannel { + c.mu.Lock() + defer c.mu.Unlock() + if c.channelHandlers == nil { + // The SSH channel has been closed. + c := make(chan NewChannel) + close(c) + return c + } + + ch := c.channelHandlers[channelType] + if ch != nil { + return nil + } + + ch = make(chan NewChannel, chanSize) + c.channelHandlers[channelType] = ch + return ch +} + +// NewClient creates a Client on top of the given connection. +func NewClient(c Conn, chans <-chan NewChannel, reqs <-chan *Request) *Client { + conn := &Client{ + Conn: c, + channelHandlers: make(map[string]chan NewChannel, 1), + } + + go conn.handleGlobalRequests(reqs) + go conn.handleChannelOpens(chans) + go func() { + conn.Wait() + conn.forwards.closeAll() + }() + return conn +} + +// NewClientConn establishes an authenticated SSH connection using c +// as the underlying transport. The Request and NewChannel channels +// must be serviced or the connection will hang. +func NewClientConn(c net.Conn, addr string, config *ClientConfig) (Conn, <-chan NewChannel, <-chan *Request, error) { + fullConf := *config + fullConf.SetDefaults() + if fullConf.HostKeyCallback == nil { + c.Close() + return nil, nil, nil, errors.New("ssh: must specify HostKeyCallback") + } + + conn := &connection{ + sshConn: sshConn{conn: c, user: fullConf.User}, + } + + if err := conn.clientHandshake(addr, &fullConf); err != nil { + c.Close() + return nil, nil, nil, fmt.Errorf("ssh: handshake failed: %w", err) + } + conn.mux = newMux(conn.transport) + return conn, conn.mux.incomingChannels, conn.mux.incomingRequests, nil +} + +// clientHandshake performs the client side key exchange. See RFC 4253 Section +// 7. +func (c *connection) clientHandshake(dialAddress string, config *ClientConfig) error { + if config.ClientVersion != "" { + c.clientVersion = []byte(config.ClientVersion) + } else { + c.clientVersion = []byte(packageVersion) + } + var err error + c.serverVersion, err = exchangeVersions(c.sshConn.conn, c.clientVersion) + if err != nil { + return err + } + + c.transport = newClientTransport( + newTransport(c.sshConn.conn, config.Rand, true /* is client */), + c.clientVersion, c.serverVersion, config, dialAddress, c.sshConn.RemoteAddr()) + if err := c.transport.waitSession(); err != nil { + return err + } + + c.sessionID = c.transport.getSessionID() + return c.clientAuthenticate(config) +} + +// verifyHostKeySignature verifies the host key obtained in the key exchange. +// algo is the negotiated algorithm, and may be a certificate type. +func verifyHostKeySignature(hostKey PublicKey, algo string, result *kexResult) error { + sig, rest, ok := parseSignatureBody(result.Signature) + if len(rest) > 0 || !ok { + return errors.New("ssh: signature parse error") + } + + if a := underlyingAlgo(algo); sig.Format != a { + return fmt.Errorf("ssh: invalid signature algorithm %q, expected %q", sig.Format, a) + } + + return hostKey.Verify(result.H, sig) +} + +// NewSession opens a new Session for this client. (A session is a remote +// execution of a program.) +func (c *Client) NewSession() (*Session, error) { + ch, in, err := c.OpenChannel("session", nil) + if err != nil { + return nil, err + } + return newSession(ch, in) +} + +func (c *Client) handleGlobalRequests(incoming <-chan *Request) { + for r := range incoming { + // This handles keepalive messages and matches + // the behaviour of OpenSSH. + r.Reply(false, nil) + } +} + +// handleChannelOpens channel open messages from the remote side. +func (c *Client) handleChannelOpens(in <-chan NewChannel) { + for ch := range in { + c.mu.Lock() + handler := c.channelHandlers[ch.ChannelType()] + c.mu.Unlock() + + if handler != nil { + handler <- ch + } else { + ch.Reject(UnknownChannelType, fmt.Sprintf("unknown channel type: %v", ch.ChannelType())) + } + } + + c.mu.Lock() + for _, ch := range c.channelHandlers { + close(ch) + } + c.channelHandlers = nil + c.mu.Unlock() +} + +// Dial starts a client connection to the given SSH server. It is a +// convenience function that connects to the given network address, +// initiates the SSH handshake, and then sets up a Client. For access +// to incoming channels and requests, use net.Dial with NewClientConn +// instead. +func Dial(network, addr string, config *ClientConfig) (*Client, error) { + conn, err := net.DialTimeout(network, addr, config.Timeout) + if err != nil { + return nil, err + } + c, chans, reqs, err := NewClientConn(conn, addr, config) + if err != nil { + return nil, err + } + return NewClient(c, chans, reqs), nil +} + +// HostKeyCallback is the function type used for verifying server +// keys. A HostKeyCallback must return nil if the host key is OK, or +// an error to reject it. It receives the hostname as passed to Dial +// or NewClientConn. The remote address is the RemoteAddr of the +// net.Conn underlying the SSH connection. +type HostKeyCallback func(hostname string, remote net.Addr, key PublicKey) error + +// BannerCallback is the function type used for treat the banner sent by +// the server. A BannerCallback receives the message sent by the remote server. +type BannerCallback func(message string) error + +// A ClientConfig structure is used to configure a Client. It must not be +// modified after having been passed to an SSH function. +type ClientConfig struct { + // Config contains configuration that is shared between clients and + // servers. + Config + + // User contains the username to authenticate as. + User string + + // Auth contains possible authentication methods to use with the + // server. Only the first instance of a particular RFC 4252 method will + // be used during authentication. + Auth []AuthMethod + + // HostKeyCallback is called during the cryptographic + // handshake to validate the server's host key. The client + // configuration must supply this callback for the connection + // to succeed. The functions InsecureIgnoreHostKey or + // FixedHostKey can be used for simplistic host key checks. + HostKeyCallback HostKeyCallback + + // BannerCallback is called during the SSH dance to display a custom + // server's message. The client configuration can supply this callback to + // handle it as wished. The function BannerDisplayStderr can be used for + // simplistic display on Stderr. + BannerCallback BannerCallback + + // ClientVersion contains the version identification string that will + // be used for the connection. If empty, a reasonable default is used. + ClientVersion string + + // HostKeyAlgorithms lists the public key algorithms that the client will + // accept from the server for host key authentication, in order of + // preference. If empty, a reasonable default is used. Any + // string returned from a PublicKey.Type method may be used, or + // any of the CertAlgo and KeyAlgo constants. + HostKeyAlgorithms []string + + // Timeout is the maximum amount of time for the TCP connection to establish. + // + // A Timeout of zero means no timeout. + Timeout time.Duration +} + +// InsecureIgnoreHostKey returns a function that can be used for +// ClientConfig.HostKeyCallback to accept any host key. It should +// not be used for production code. +func InsecureIgnoreHostKey() HostKeyCallback { + return func(hostname string, remote net.Addr, key PublicKey) error { + return nil + } +} + +type fixedHostKey struct { + key PublicKey +} + +func (f *fixedHostKey) check(hostname string, remote net.Addr, key PublicKey) error { + if f.key == nil { + return fmt.Errorf("ssh: required host key was nil") + } + if !bytes.Equal(key.Marshal(), f.key.Marshal()) { + return fmt.Errorf("ssh: host key mismatch") + } + return nil +} + +// FixedHostKey returns a function for use in +// ClientConfig.HostKeyCallback to accept only a specific host key. +func FixedHostKey(key PublicKey) HostKeyCallback { + hk := &fixedHostKey{key} + return hk.check +} + +// BannerDisplayStderr returns a function that can be used for +// ClientConfig.BannerCallback to display banners on os.Stderr. +func BannerDisplayStderr() BannerCallback { + return func(banner string) error { + _, err := os.Stderr.WriteString(banner) + + return err + } +} diff --git a/tempfork/sshtest/ssh/client_auth.go b/tempfork/sshtest/ssh/client_auth.go new file mode 100644 index 000000000..b86dde151 --- /dev/null +++ b/tempfork/sshtest/ssh/client_auth.go @@ -0,0 +1,796 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "bytes" + "errors" + "fmt" + "io" + "strings" +) + +type authResult int + +const ( + authFailure authResult = iota + authPartialSuccess + authSuccess +) + +// clientAuthenticate authenticates with the remote server. See RFC 4252. +func (c *connection) clientAuthenticate(config *ClientConfig) error { + // initiate user auth session + if err := c.transport.writePacket(Marshal(&serviceRequestMsg{serviceUserAuth})); err != nil { + return err + } + packet, err := c.transport.readPacket() + if err != nil { + return err + } + // The server may choose to send a SSH_MSG_EXT_INFO at this point (if we + // advertised willingness to receive one, which we always do) or not. See + // RFC 8308, Section 2.4. + extensions := make(map[string][]byte) + if len(packet) > 0 && packet[0] == msgExtInfo { + var extInfo extInfoMsg + if err := Unmarshal(packet, &extInfo); err != nil { + return err + } + payload := extInfo.Payload + for i := uint32(0); i < extInfo.NumExtensions; i++ { + name, rest, ok := parseString(payload) + if !ok { + return parseError(msgExtInfo) + } + value, rest, ok := parseString(rest) + if !ok { + return parseError(msgExtInfo) + } + extensions[string(name)] = value + payload = rest + } + packet, err = c.transport.readPacket() + if err != nil { + return err + } + } + var serviceAccept serviceAcceptMsg + if err := Unmarshal(packet, &serviceAccept); err != nil { + return err + } + + // during the authentication phase the client first attempts the "none" method + // then any untried methods suggested by the server. + var tried []string + var lastMethods []string + + sessionID := c.transport.getSessionID() + for auth := AuthMethod(new(noneAuth)); auth != nil; { + ok, methods, err := auth.auth(sessionID, config.User, c.transport, config.Rand, extensions) + if err != nil { + // On disconnect, return error immediately + if _, ok := err.(*disconnectMsg); ok { + return err + } + // We return the error later if there is no other method left to + // try. + ok = authFailure + } + if ok == authSuccess { + // success + return nil + } else if ok == authFailure { + if m := auth.method(); !contains(tried, m) { + tried = append(tried, m) + } + } + if methods == nil { + methods = lastMethods + } + lastMethods = methods + + auth = nil + + findNext: + for _, a := range config.Auth { + candidateMethod := a.method() + if contains(tried, candidateMethod) { + continue + } + for _, meth := range methods { + if meth == candidateMethod { + auth = a + break findNext + } + } + } + + if auth == nil && err != nil { + // We have an error and there are no other authentication methods to + // try, so we return it. + return err + } + } + return fmt.Errorf("ssh: unable to authenticate, attempted methods %v, no supported methods remain", tried) +} + +func contains(list []string, e string) bool { + for _, s := range list { + if s == e { + return true + } + } + return false +} + +// An AuthMethod represents an instance of an RFC 4252 authentication method. +type AuthMethod interface { + // auth authenticates user over transport t. + // Returns true if authentication is successful. + // If authentication is not successful, a []string of alternative + // method names is returned. If the slice is nil, it will be ignored + // and the previous set of possible methods will be reused. + auth(session []byte, user string, p packetConn, rand io.Reader, extensions map[string][]byte) (authResult, []string, error) + + // method returns the RFC 4252 method name. + method() string +} + +// "none" authentication, RFC 4252 section 5.2. +type noneAuth int + +func (n *noneAuth) auth(session []byte, user string, c packetConn, rand io.Reader, _ map[string][]byte) (authResult, []string, error) { + if err := c.writePacket(Marshal(&userAuthRequestMsg{ + User: user, + Service: serviceSSH, + Method: "none", + })); err != nil { + return authFailure, nil, err + } + + return handleAuthResponse(c) +} + +func (n *noneAuth) method() string { + return "none" +} + +// passwordCallback is an AuthMethod that fetches the password through +// a function call, e.g. by prompting the user. +type passwordCallback func() (password string, err error) + +func (cb passwordCallback) auth(session []byte, user string, c packetConn, rand io.Reader, _ map[string][]byte) (authResult, []string, error) { + type passwordAuthMsg struct { + User string `sshtype:"50"` + Service string + Method string + Reply bool + Password string + } + + pw, err := cb() + // REVIEW NOTE: is there a need to support skipping a password attempt? + // The program may only find out that the user doesn't have a password + // when prompting. + if err != nil { + return authFailure, nil, err + } + + if err := c.writePacket(Marshal(&passwordAuthMsg{ + User: user, + Service: serviceSSH, + Method: cb.method(), + Reply: false, + Password: pw, + })); err != nil { + return authFailure, nil, err + } + + return handleAuthResponse(c) +} + +func (cb passwordCallback) method() string { + return "password" +} + +// Password returns an AuthMethod using the given password. +func Password(secret string) AuthMethod { + return passwordCallback(func() (string, error) { return secret, nil }) +} + +// PasswordCallback returns an AuthMethod that uses a callback for +// fetching a password. +func PasswordCallback(prompt func() (secret string, err error)) AuthMethod { + return passwordCallback(prompt) +} + +type publickeyAuthMsg struct { + User string `sshtype:"50"` + Service string + Method string + // HasSig indicates to the receiver packet that the auth request is signed and + // should be used for authentication of the request. + HasSig bool + Algoname string + PubKey []byte + // Sig is tagged with "rest" so Marshal will exclude it during + // validateKey + Sig []byte `ssh:"rest"` +} + +// publicKeyCallback is an AuthMethod that uses a set of key +// pairs for authentication. +type publicKeyCallback func() ([]Signer, error) + +func (cb publicKeyCallback) method() string { + return "publickey" +} + +func pickSignatureAlgorithm(signer Signer, extensions map[string][]byte) (MultiAlgorithmSigner, string, error) { + var as MultiAlgorithmSigner + keyFormat := signer.PublicKey().Type() + + // If the signer implements MultiAlgorithmSigner we use the algorithms it + // support, if it implements AlgorithmSigner we assume it supports all + // algorithms, otherwise only the key format one. + switch s := signer.(type) { + case MultiAlgorithmSigner: + as = s + case AlgorithmSigner: + as = &multiAlgorithmSigner{ + AlgorithmSigner: s, + supportedAlgorithms: algorithmsForKeyFormat(underlyingAlgo(keyFormat)), + } + default: + as = &multiAlgorithmSigner{ + AlgorithmSigner: algorithmSignerWrapper{signer}, + supportedAlgorithms: []string{underlyingAlgo(keyFormat)}, + } + } + + getFallbackAlgo := func() (string, error) { + // Fallback to use if there is no "server-sig-algs" extension or a + // common algorithm cannot be found. We use the public key format if the + // MultiAlgorithmSigner supports it, otherwise we return an error. + if !contains(as.Algorithms(), underlyingAlgo(keyFormat)) { + return "", fmt.Errorf("ssh: no common public key signature algorithm, server only supports %q for key type %q, signer only supports %v", + underlyingAlgo(keyFormat), keyFormat, as.Algorithms()) + } + return keyFormat, nil + } + + extPayload, ok := extensions["server-sig-algs"] + if !ok { + // If there is no "server-sig-algs" extension use the fallback + // algorithm. + algo, err := getFallbackAlgo() + return as, algo, err + } + + // The server-sig-algs extension only carries underlying signature + // algorithm, but we are trying to select a protocol-level public key + // algorithm, which might be a certificate type. Extend the list of server + // supported algorithms to include the corresponding certificate algorithms. + serverAlgos := strings.Split(string(extPayload), ",") + for _, algo := range serverAlgos { + if certAlgo, ok := certificateAlgo(algo); ok { + serverAlgos = append(serverAlgos, certAlgo) + } + } + + // Filter algorithms based on those supported by MultiAlgorithmSigner. + var keyAlgos []string + for _, algo := range algorithmsForKeyFormat(keyFormat) { + if contains(as.Algorithms(), underlyingAlgo(algo)) { + keyAlgos = append(keyAlgos, algo) + } + } + + algo, err := findCommon("public key signature algorithm", keyAlgos, serverAlgos) + if err != nil { + // If there is no overlap, return the fallback algorithm to support + // servers that fail to list all supported algorithms. + algo, err := getFallbackAlgo() + return as, algo, err + } + return as, algo, nil +} + +func (cb publicKeyCallback) auth(session []byte, user string, c packetConn, rand io.Reader, extensions map[string][]byte) (authResult, []string, error) { + // Authentication is performed by sending an enquiry to test if a key is + // acceptable to the remote. If the key is acceptable, the client will + // attempt to authenticate with the valid key. If not the client will repeat + // the process with the remaining keys. + + signers, err := cb() + if err != nil { + return authFailure, nil, err + } + var methods []string + var errSigAlgo error + + origSignersLen := len(signers) + for idx := 0; idx < len(signers); idx++ { + signer := signers[idx] + pub := signer.PublicKey() + as, algo, err := pickSignatureAlgorithm(signer, extensions) + if err != nil && errSigAlgo == nil { + // If we cannot negotiate a signature algorithm store the first + // error so we can return it to provide a more meaningful message if + // no other signers work. + errSigAlgo = err + continue + } + ok, err := validateKey(pub, algo, user, c) + if err != nil { + return authFailure, nil, err + } + // OpenSSH 7.2-7.7 advertises support for rsa-sha2-256 and rsa-sha2-512 + // in the "server-sig-algs" extension but doesn't support these + // algorithms for certificate authentication, so if the server rejects + // the key try to use the obtained algorithm as if "server-sig-algs" had + // not been implemented if supported from the algorithm signer. + if !ok && idx < origSignersLen && isRSACert(algo) && algo != CertAlgoRSAv01 { + if contains(as.Algorithms(), KeyAlgoRSA) { + // We retry using the compat algorithm after all signers have + // been tried normally. + signers = append(signers, &multiAlgorithmSigner{ + AlgorithmSigner: as, + supportedAlgorithms: []string{KeyAlgoRSA}, + }) + } + } + if !ok { + continue + } + + pubKey := pub.Marshal() + data := buildDataSignedForAuth(session, userAuthRequestMsg{ + User: user, + Service: serviceSSH, + Method: cb.method(), + }, algo, pubKey) + sign, err := as.SignWithAlgorithm(rand, data, underlyingAlgo(algo)) + if err != nil { + return authFailure, nil, err + } + + // manually wrap the serialized signature in a string + s := Marshal(sign) + sig := make([]byte, stringLength(len(s))) + marshalString(sig, s) + msg := publickeyAuthMsg{ + User: user, + Service: serviceSSH, + Method: cb.method(), + HasSig: true, + Algoname: algo, + PubKey: pubKey, + Sig: sig, + } + p := Marshal(&msg) + if err := c.writePacket(p); err != nil { + return authFailure, nil, err + } + var success authResult + success, methods, err = handleAuthResponse(c) + if err != nil { + return authFailure, nil, err + } + + // If authentication succeeds or the list of available methods does not + // contain the "publickey" method, do not attempt to authenticate with any + // other keys. According to RFC 4252 Section 7, the latter can occur when + // additional authentication methods are required. + if success == authSuccess || !contains(methods, cb.method()) { + return success, methods, err + } + } + + return authFailure, methods, errSigAlgo +} + +// validateKey validates the key provided is acceptable to the server. +func validateKey(key PublicKey, algo string, user string, c packetConn) (bool, error) { + pubKey := key.Marshal() + msg := publickeyAuthMsg{ + User: user, + Service: serviceSSH, + Method: "publickey", + HasSig: false, + Algoname: algo, + PubKey: pubKey, + } + if err := c.writePacket(Marshal(&msg)); err != nil { + return false, err + } + + return confirmKeyAck(key, c) +} + +func confirmKeyAck(key PublicKey, c packetConn) (bool, error) { + pubKey := key.Marshal() + + for { + packet, err := c.readPacket() + if err != nil { + return false, err + } + switch packet[0] { + case msgUserAuthBanner: + if err := handleBannerResponse(c, packet); err != nil { + return false, err + } + case msgUserAuthPubKeyOk: + var msg userAuthPubKeyOkMsg + if err := Unmarshal(packet, &msg); err != nil { + return false, err + } + // According to RFC 4252 Section 7 the algorithm in + // SSH_MSG_USERAUTH_PK_OK should match that of the request but some + // servers send the key type instead. OpenSSH allows any algorithm + // that matches the public key, so we do the same. + // https://github.com/openssh/openssh-portable/blob/86bdd385/sshconnect2.c#L709 + if !contains(algorithmsForKeyFormat(key.Type()), msg.Algo) { + return false, nil + } + if !bytes.Equal(msg.PubKey, pubKey) { + return false, nil + } + return true, nil + case msgUserAuthFailure: + return false, nil + default: + return false, unexpectedMessageError(msgUserAuthPubKeyOk, packet[0]) + } + } +} + +// PublicKeys returns an AuthMethod that uses the given key +// pairs. +func PublicKeys(signers ...Signer) AuthMethod { + return publicKeyCallback(func() ([]Signer, error) { return signers, nil }) +} + +// PublicKeysCallback returns an AuthMethod that runs the given +// function to obtain a list of key pairs. +func PublicKeysCallback(getSigners func() (signers []Signer, err error)) AuthMethod { + return publicKeyCallback(getSigners) +} + +// handleAuthResponse returns whether the preceding authentication request succeeded +// along with a list of remaining authentication methods to try next and +// an error if an unexpected response was received. +func handleAuthResponse(c packetConn) (authResult, []string, error) { + gotMsgExtInfo := false + for { + packet, err := c.readPacket() + if err != nil { + return authFailure, nil, err + } + + switch packet[0] { + case msgUserAuthBanner: + if err := handleBannerResponse(c, packet); err != nil { + return authFailure, nil, err + } + case msgExtInfo: + // Ignore post-authentication RFC 8308 extensions, once. + if gotMsgExtInfo { + return authFailure, nil, unexpectedMessageError(msgUserAuthSuccess, packet[0]) + } + gotMsgExtInfo = true + case msgUserAuthFailure: + var msg userAuthFailureMsg + if err := Unmarshal(packet, &msg); err != nil { + return authFailure, nil, err + } + if msg.PartialSuccess { + return authPartialSuccess, msg.Methods, nil + } + return authFailure, msg.Methods, nil + case msgUserAuthSuccess: + return authSuccess, nil, nil + default: + return authFailure, nil, unexpectedMessageError(msgUserAuthSuccess, packet[0]) + } + } +} + +func handleBannerResponse(c packetConn, packet []byte) error { + var msg userAuthBannerMsg + if err := Unmarshal(packet, &msg); err != nil { + return err + } + + transport, ok := c.(*handshakeTransport) + if !ok { + return nil + } + + if transport.bannerCallback != nil { + return transport.bannerCallback(msg.Message) + } + + return nil +} + +// KeyboardInteractiveChallenge should print questions, optionally +// disabling echoing (e.g. for passwords), and return all the answers. +// Challenge may be called multiple times in a single session. After +// successful authentication, the server may send a challenge with no +// questions, for which the name and instruction messages should be +// printed. RFC 4256 section 3.3 details how the UI should behave for +// both CLI and GUI environments. +type KeyboardInteractiveChallenge func(name, instruction string, questions []string, echos []bool) (answers []string, err error) + +// KeyboardInteractive returns an AuthMethod using a prompt/response +// sequence controlled by the server. +func KeyboardInteractive(challenge KeyboardInteractiveChallenge) AuthMethod { + return challenge +} + +func (cb KeyboardInteractiveChallenge) method() string { + return "keyboard-interactive" +} + +func (cb KeyboardInteractiveChallenge) auth(session []byte, user string, c packetConn, rand io.Reader, _ map[string][]byte) (authResult, []string, error) { + type initiateMsg struct { + User string `sshtype:"50"` + Service string + Method string + Language string + Submethods string + } + + if err := c.writePacket(Marshal(&initiateMsg{ + User: user, + Service: serviceSSH, + Method: "keyboard-interactive", + })); err != nil { + return authFailure, nil, err + } + + gotMsgExtInfo := false + gotUserAuthInfoRequest := false + for { + packet, err := c.readPacket() + if err != nil { + return authFailure, nil, err + } + + // like handleAuthResponse, but with less options. + switch packet[0] { + case msgUserAuthBanner: + if err := handleBannerResponse(c, packet); err != nil { + return authFailure, nil, err + } + continue + case msgExtInfo: + // Ignore post-authentication RFC 8308 extensions, once. + if gotMsgExtInfo { + return authFailure, nil, unexpectedMessageError(msgUserAuthInfoRequest, packet[0]) + } + gotMsgExtInfo = true + continue + case msgUserAuthInfoRequest: + // OK + case msgUserAuthFailure: + var msg userAuthFailureMsg + if err := Unmarshal(packet, &msg); err != nil { + return authFailure, nil, err + } + if msg.PartialSuccess { + return authPartialSuccess, msg.Methods, nil + } + if !gotUserAuthInfoRequest { + return authFailure, msg.Methods, unexpectedMessageError(msgUserAuthInfoRequest, packet[0]) + } + return authFailure, msg.Methods, nil + case msgUserAuthSuccess: + return authSuccess, nil, nil + default: + return authFailure, nil, unexpectedMessageError(msgUserAuthInfoRequest, packet[0]) + } + + var msg userAuthInfoRequestMsg + if err := Unmarshal(packet, &msg); err != nil { + return authFailure, nil, err + } + gotUserAuthInfoRequest = true + + // Manually unpack the prompt/echo pairs. + rest := msg.Prompts + var prompts []string + var echos []bool + for i := 0; i < int(msg.NumPrompts); i++ { + prompt, r, ok := parseString(rest) + if !ok || len(r) == 0 { + return authFailure, nil, errors.New("ssh: prompt format error") + } + prompts = append(prompts, string(prompt)) + echos = append(echos, r[0] != 0) + rest = r[1:] + } + + if len(rest) != 0 { + return authFailure, nil, errors.New("ssh: extra data following keyboard-interactive pairs") + } + + answers, err := cb(msg.Name, msg.Instruction, prompts, echos) + if err != nil { + return authFailure, nil, err + } + + if len(answers) != len(prompts) { + return authFailure, nil, fmt.Errorf("ssh: incorrect number of answers from keyboard-interactive callback %d (expected %d)", len(answers), len(prompts)) + } + responseLength := 1 + 4 + for _, a := range answers { + responseLength += stringLength(len(a)) + } + serialized := make([]byte, responseLength) + p := serialized + p[0] = msgUserAuthInfoResponse + p = p[1:] + p = marshalUint32(p, uint32(len(answers))) + for _, a := range answers { + p = marshalString(p, []byte(a)) + } + + if err := c.writePacket(serialized); err != nil { + return authFailure, nil, err + } + } +} + +type retryableAuthMethod struct { + authMethod AuthMethod + maxTries int +} + +func (r *retryableAuthMethod) auth(session []byte, user string, c packetConn, rand io.Reader, extensions map[string][]byte) (ok authResult, methods []string, err error) { + for i := 0; r.maxTries <= 0 || i < r.maxTries; i++ { + ok, methods, err = r.authMethod.auth(session, user, c, rand, extensions) + if ok != authFailure || err != nil { // either success, partial success or error terminate + return ok, methods, err + } + } + return ok, methods, err +} + +func (r *retryableAuthMethod) method() string { + return r.authMethod.method() +} + +// RetryableAuthMethod is a decorator for other auth methods enabling them to +// be retried up to maxTries before considering that AuthMethod itself failed. +// If maxTries is <= 0, will retry indefinitely +// +// This is useful for interactive clients using challenge/response type +// authentication (e.g. Keyboard-Interactive, Password, etc) where the user +// could mistype their response resulting in the server issuing a +// SSH_MSG_USERAUTH_FAILURE (rfc4252 #8 [password] and rfc4256 #3.4 +// [keyboard-interactive]); Without this decorator, the non-retryable +// AuthMethod would be removed from future consideration, and never tried again +// (and so the user would never be able to retry their entry). +func RetryableAuthMethod(auth AuthMethod, maxTries int) AuthMethod { + return &retryableAuthMethod{authMethod: auth, maxTries: maxTries} +} + +// GSSAPIWithMICAuthMethod is an AuthMethod with "gssapi-with-mic" authentication. +// See RFC 4462 section 3 +// gssAPIClient is implementation of the GSSAPIClient interface, see the definition of the interface for details. +// target is the server host you want to log in to. +func GSSAPIWithMICAuthMethod(gssAPIClient GSSAPIClient, target string) AuthMethod { + if gssAPIClient == nil { + panic("gss-api client must be not nil with enable gssapi-with-mic") + } + return &gssAPIWithMICCallback{gssAPIClient: gssAPIClient, target: target} +} + +type gssAPIWithMICCallback struct { + gssAPIClient GSSAPIClient + target string +} + +func (g *gssAPIWithMICCallback) auth(session []byte, user string, c packetConn, rand io.Reader, _ map[string][]byte) (authResult, []string, error) { + m := &userAuthRequestMsg{ + User: user, + Service: serviceSSH, + Method: g.method(), + } + // The GSS-API authentication method is initiated when the client sends an SSH_MSG_USERAUTH_REQUEST. + // See RFC 4462 section 3.2. + m.Payload = appendU32(m.Payload, 1) + m.Payload = appendString(m.Payload, string(krb5OID)) + if err := c.writePacket(Marshal(m)); err != nil { + return authFailure, nil, err + } + // The server responds to the SSH_MSG_USERAUTH_REQUEST with either an + // SSH_MSG_USERAUTH_FAILURE if none of the mechanisms are supported or + // with an SSH_MSG_USERAUTH_GSSAPI_RESPONSE. + // See RFC 4462 section 3.3. + // OpenSSH supports Kerberos V5 mechanism only for GSS-API authentication,so I don't want to check + // selected mech if it is valid. + packet, err := c.readPacket() + if err != nil { + return authFailure, nil, err + } + userAuthGSSAPIResp := &userAuthGSSAPIResponse{} + if err := Unmarshal(packet, userAuthGSSAPIResp); err != nil { + return authFailure, nil, err + } + // Start the loop into the exchange token. + // See RFC 4462 section 3.4. + var token []byte + defer g.gssAPIClient.DeleteSecContext() + for { + // Initiates the establishment of a security context between the application and a remote peer. + nextToken, needContinue, err := g.gssAPIClient.InitSecContext("host@"+g.target, token, false) + if err != nil { + return authFailure, nil, err + } + if len(nextToken) > 0 { + if err := c.writePacket(Marshal(&userAuthGSSAPIToken{ + Token: nextToken, + })); err != nil { + return authFailure, nil, err + } + } + if !needContinue { + break + } + packet, err = c.readPacket() + if err != nil { + return authFailure, nil, err + } + switch packet[0] { + case msgUserAuthFailure: + var msg userAuthFailureMsg + if err := Unmarshal(packet, &msg); err != nil { + return authFailure, nil, err + } + if msg.PartialSuccess { + return authPartialSuccess, msg.Methods, nil + } + return authFailure, msg.Methods, nil + case msgUserAuthGSSAPIError: + userAuthGSSAPIErrorResp := &userAuthGSSAPIError{} + if err := Unmarshal(packet, userAuthGSSAPIErrorResp); err != nil { + return authFailure, nil, err + } + return authFailure, nil, fmt.Errorf("GSS-API Error:\n"+ + "Major Status: %d\n"+ + "Minor Status: %d\n"+ + "Error Message: %s\n", userAuthGSSAPIErrorResp.MajorStatus, userAuthGSSAPIErrorResp.MinorStatus, + userAuthGSSAPIErrorResp.Message) + case msgUserAuthGSSAPIToken: + userAuthGSSAPITokenReq := &userAuthGSSAPIToken{} + if err := Unmarshal(packet, userAuthGSSAPITokenReq); err != nil { + return authFailure, nil, err + } + token = userAuthGSSAPITokenReq.Token + } + } + // Binding Encryption Keys. + // See RFC 4462 section 3.5. + micField := buildMIC(string(session), user, "ssh-connection", "gssapi-with-mic") + micToken, err := g.gssAPIClient.GetMIC(micField) + if err != nil { + return authFailure, nil, err + } + if err := c.writePacket(Marshal(&userAuthGSSAPIMIC{ + MIC: micToken, + })); err != nil { + return authFailure, nil, err + } + return handleAuthResponse(c) +} + +func (g *gssAPIWithMICCallback) method() string { + return "gssapi-with-mic" +} diff --git a/tempfork/sshtest/ssh/client_auth_test.go b/tempfork/sshtest/ssh/client_auth_test.go new file mode 100644 index 000000000..ec27133a3 --- /dev/null +++ b/tempfork/sshtest/ssh/client_auth_test.go @@ -0,0 +1,1384 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "bytes" + "crypto/rand" + "errors" + "fmt" + "io" + "log" + "net" + "os" + "runtime" + "strings" + "testing" +) + +type keyboardInteractive map[string]string + +func (cr keyboardInteractive) Challenge(user string, instruction string, questions []string, echos []bool) ([]string, error) { + var answers []string + for _, q := range questions { + answers = append(answers, cr[q]) + } + return answers, nil +} + +// reused internally by tests +var clientPassword = "tiger" + +// tryAuth runs a handshake with a given config against an SSH server +// with config serverConfig. Returns both client and server side errors. +func tryAuth(t *testing.T, config *ClientConfig) error { + err, _ := tryAuthBothSides(t, config, nil) + return err +} + +// tryAuthWithGSSAPIWithMICConfig runs a handshake with a given config against an SSH server +// with a given GSSAPIWithMICConfig and config serverConfig. Returns both client and server side errors. +func tryAuthWithGSSAPIWithMICConfig(t *testing.T, clientConfig *ClientConfig, gssAPIWithMICConfig *GSSAPIWithMICConfig) error { + err, _ := tryAuthBothSides(t, clientConfig, gssAPIWithMICConfig) + return err +} + +// tryAuthBothSides runs the handshake and returns the resulting errors from both sides of the connection. +func tryAuthBothSides(t *testing.T, config *ClientConfig, gssAPIWithMICConfig *GSSAPIWithMICConfig) (clientError error, serverAuthErrors []error) { + c1, c2, err := netPipe() + if err != nil { + t.Fatalf("netPipe: %v", err) + } + defer c1.Close() + defer c2.Close() + + certChecker := CertChecker{ + IsUserAuthority: func(k PublicKey) bool { + return bytes.Equal(k.Marshal(), testPublicKeys["ecdsa"].Marshal()) + }, + UserKeyFallback: func(conn ConnMetadata, key PublicKey) (*Permissions, error) { + if conn.User() == "testuser" && bytes.Equal(key.Marshal(), testPublicKeys["rsa"].Marshal()) { + return nil, nil + } + + return nil, fmt.Errorf("pubkey for %q not acceptable", conn.User()) + }, + IsRevoked: func(c *Certificate) bool { + return c.Serial == 666 + }, + } + serverConfig := &ServerConfig{ + PasswordCallback: func(conn ConnMetadata, pass []byte) (*Permissions, error) { + if conn.User() == "testuser" && string(pass) == clientPassword { + return nil, nil + } + return nil, errors.New("password auth failed") + }, + PublicKeyCallback: certChecker.Authenticate, + KeyboardInteractiveCallback: func(conn ConnMetadata, challenge KeyboardInteractiveChallenge) (*Permissions, error) { + ans, err := challenge("user", + "instruction", + []string{"question1", "question2"}, + []bool{true, true}) + if err != nil { + return nil, err + } + ok := conn.User() == "testuser" && ans[0] == "answer1" && ans[1] == "answer2" + if ok { + challenge("user", "motd", nil, nil) + return nil, nil + } + return nil, errors.New("keyboard-interactive failed") + }, + GSSAPIWithMICConfig: gssAPIWithMICConfig, + } + serverConfig.AddHostKey(testSigners["rsa"]) + + serverConfig.AuthLogCallback = func(conn ConnMetadata, method string, err error) { + serverAuthErrors = append(serverAuthErrors, err) + } + + go newServer(c1, serverConfig) + _, _, _, err = NewClientConn(c2, "", config) + return err, serverAuthErrors +} + +type loggingAlgorithmSigner struct { + used []string + AlgorithmSigner +} + +func (l *loggingAlgorithmSigner) Sign(rand io.Reader, data []byte) (*Signature, error) { + l.used = append(l.used, "[Sign]") + return l.AlgorithmSigner.Sign(rand, data) +} + +func (l *loggingAlgorithmSigner) SignWithAlgorithm(rand io.Reader, data []byte, algorithm string) (*Signature, error) { + l.used = append(l.used, algorithm) + return l.AlgorithmSigner.SignWithAlgorithm(rand, data, algorithm) +} + +func TestClientAuthPublicKey(t *testing.T) { + signer := &loggingAlgorithmSigner{AlgorithmSigner: testSigners["rsa"].(AlgorithmSigner)} + config := &ClientConfig{ + User: "testuser", + Auth: []AuthMethod{ + PublicKeys(signer), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + if err := tryAuth(t, config); err != nil { + t.Fatalf("unable to dial remote side: %s", err) + } + if len(signer.used) != 1 || signer.used[0] != KeyAlgoRSASHA256 { + t.Errorf("unexpected Sign/SignWithAlgorithm calls: %q", signer.used) + } +} + +// TestClientAuthNoSHA2 tests a ssh-rsa Signer that doesn't implement AlgorithmSigner. +func TestClientAuthNoSHA2(t *testing.T) { + config := &ClientConfig{ + User: "testuser", + Auth: []AuthMethod{ + PublicKeys(&legacyRSASigner{testSigners["rsa"]}), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + if err := tryAuth(t, config); err != nil { + t.Fatalf("unable to dial remote side: %s", err) + } +} + +// TestClientAuthThirdKey checks that the third configured can succeed. If we +// were to do three attempts for each key (rsa-sha2-256, rsa-sha2-512, ssh-rsa), +// we'd hit the six maximum attempts before reaching it. +func TestClientAuthThirdKey(t *testing.T) { + config := &ClientConfig{ + User: "testuser", + Auth: []AuthMethod{ + PublicKeys(testSigners["rsa-openssh-format"], + testSigners["rsa-openssh-format"], testSigners["rsa"]), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + if err := tryAuth(t, config); err != nil { + t.Fatalf("unable to dial remote side: %s", err) + } +} + +func TestAuthMethodPassword(t *testing.T) { + config := &ClientConfig{ + User: "testuser", + Auth: []AuthMethod{ + Password(clientPassword), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + + if err := tryAuth(t, config); err != nil { + t.Fatalf("unable to dial remote side: %s", err) + } +} + +func TestAuthMethodFallback(t *testing.T) { + var passwordCalled bool + config := &ClientConfig{ + User: "testuser", + Auth: []AuthMethod{ + PublicKeys(testSigners["rsa"]), + PasswordCallback( + func() (string, error) { + passwordCalled = true + return "WRONG", nil + }), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + + if err := tryAuth(t, config); err != nil { + t.Fatalf("unable to dial remote side: %s", err) + } + + if passwordCalled { + t.Errorf("password auth tried before public-key auth.") + } +} + +func TestAuthMethodWrongPassword(t *testing.T) { + config := &ClientConfig{ + User: "testuser", + Auth: []AuthMethod{ + Password("wrong"), + PublicKeys(testSigners["rsa"]), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + + if err := tryAuth(t, config); err != nil { + t.Fatalf("unable to dial remote side: %s", err) + } +} + +func TestAuthMethodKeyboardInteractive(t *testing.T) { + answers := keyboardInteractive(map[string]string{ + "question1": "answer1", + "question2": "answer2", + }) + config := &ClientConfig{ + User: "testuser", + Auth: []AuthMethod{ + KeyboardInteractive(answers.Challenge), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + + if err := tryAuth(t, config); err != nil { + t.Fatalf("unable to dial remote side: %s", err) + } +} + +func TestAuthMethodWrongKeyboardInteractive(t *testing.T) { + answers := keyboardInteractive(map[string]string{ + "question1": "answer1", + "question2": "WRONG", + }) + config := &ClientConfig{ + User: "testuser", + Auth: []AuthMethod{ + KeyboardInteractive(answers.Challenge), + }, + } + + if err := tryAuth(t, config); err == nil { + t.Fatalf("wrong answers should not have authenticated with KeyboardInteractive") + } +} + +// the mock server will only authenticate ssh-rsa keys +func TestAuthMethodInvalidPublicKey(t *testing.T) { + config := &ClientConfig{ + User: "testuser", + Auth: []AuthMethod{ + PublicKeys(testSigners["dsa"]), + }, + } + + if err := tryAuth(t, config); err == nil { + t.Fatalf("dsa private key should not have authenticated with rsa public key") + } +} + +// the client should authenticate with the second key +func TestAuthMethodRSAandDSA(t *testing.T) { + config := &ClientConfig{ + User: "testuser", + Auth: []AuthMethod{ + PublicKeys(testSigners["dsa"], testSigners["rsa"]), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + if err := tryAuth(t, config); err != nil { + t.Fatalf("client could not authenticate with rsa key: %v", err) + } +} + +type invalidAlgSigner struct { + Signer +} + +func (s *invalidAlgSigner) Sign(rand io.Reader, data []byte) (*Signature, error) { + sig, err := s.Signer.Sign(rand, data) + if sig != nil { + sig.Format = "invalid" + } + return sig, err +} + +func TestMethodInvalidAlgorithm(t *testing.T) { + config := &ClientConfig{ + User: "testuser", + Auth: []AuthMethod{ + PublicKeys(&invalidAlgSigner{testSigners["rsa"]}), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + + err, serverErrors := tryAuthBothSides(t, config, nil) + if err == nil { + t.Fatalf("login succeeded") + } + + found := false + want := "algorithm \"invalid\"" + + var errStrings []string + for _, err := range serverErrors { + found = found || (err != nil && strings.Contains(err.Error(), want)) + errStrings = append(errStrings, err.Error()) + } + if !found { + t.Errorf("server got error %q, want substring %q", errStrings, want) + } +} + +func TestClientHMAC(t *testing.T) { + for _, mac := range supportedMACs { + config := &ClientConfig{ + User: "testuser", + Auth: []AuthMethod{ + PublicKeys(testSigners["rsa"]), + }, + Config: Config{ + MACs: []string{mac}, + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + if err := tryAuth(t, config); err != nil { + t.Fatalf("client could not authenticate with mac algo %s: %v", mac, err) + } + } +} + +// issue 4285. +func TestClientUnsupportedCipher(t *testing.T) { + config := &ClientConfig{ + User: "testuser", + Auth: []AuthMethod{ + PublicKeys(), + }, + Config: Config{ + Ciphers: []string{"aes128-cbc"}, // not currently supported + }, + } + if err := tryAuth(t, config); err == nil { + t.Errorf("expected no ciphers in common") + } +} + +func TestClientUnsupportedKex(t *testing.T) { + if os.Getenv("GO_BUILDER_NAME") != "" { + t.Skip("skipping known-flaky test on the Go build dashboard; see golang.org/issue/15198") + } + config := &ClientConfig{ + User: "testuser", + Auth: []AuthMethod{ + PublicKeys(), + }, + Config: Config{ + KeyExchanges: []string{"non-existent-kex"}, + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + if err := tryAuth(t, config); err == nil || !strings.Contains(err.Error(), "common algorithm") { + t.Errorf("got %v, expected 'common algorithm'", err) + } +} + +func TestClientLoginCert(t *testing.T) { + cert := &Certificate{ + Key: testPublicKeys["rsa"], + ValidBefore: CertTimeInfinity, + CertType: UserCert, + } + cert.SignCert(rand.Reader, testSigners["ecdsa"]) + certSigner, err := NewCertSigner(cert, testSigners["rsa"]) + if err != nil { + t.Fatalf("NewCertSigner: %v", err) + } + + clientConfig := &ClientConfig{ + User: "user", + HostKeyCallback: InsecureIgnoreHostKey(), + } + clientConfig.Auth = append(clientConfig.Auth, PublicKeys(certSigner)) + + // should succeed + if err := tryAuth(t, clientConfig); err != nil { + t.Errorf("cert login failed: %v", err) + } + + // corrupted signature + cert.Signature.Blob[0]++ + if err := tryAuth(t, clientConfig); err == nil { + t.Errorf("cert login passed with corrupted sig") + } + + // revoked + cert.Serial = 666 + cert.SignCert(rand.Reader, testSigners["ecdsa"]) + if err := tryAuth(t, clientConfig); err == nil { + t.Errorf("revoked cert login succeeded") + } + cert.Serial = 1 + + // sign with wrong key + cert.SignCert(rand.Reader, testSigners["dsa"]) + if err := tryAuth(t, clientConfig); err == nil { + t.Errorf("cert login passed with non-authoritative key") + } + + // host cert + cert.CertType = HostCert + cert.SignCert(rand.Reader, testSigners["ecdsa"]) + if err := tryAuth(t, clientConfig); err == nil { + t.Errorf("cert login passed with wrong type") + } + cert.CertType = UserCert + + // principal specified + cert.ValidPrincipals = []string{"user"} + cert.SignCert(rand.Reader, testSigners["ecdsa"]) + if err := tryAuth(t, clientConfig); err != nil { + t.Errorf("cert login failed: %v", err) + } + + // wrong principal specified + cert.ValidPrincipals = []string{"fred"} + cert.SignCert(rand.Reader, testSigners["ecdsa"]) + if err := tryAuth(t, clientConfig); err == nil { + t.Errorf("cert login passed with wrong principal") + } + cert.ValidPrincipals = nil + + // added critical option + cert.CriticalOptions = map[string]string{"root-access": "yes"} + cert.SignCert(rand.Reader, testSigners["ecdsa"]) + if err := tryAuth(t, clientConfig); err == nil { + t.Errorf("cert login passed with unrecognized critical option") + } + + // allowed source address + cert.CriticalOptions = map[string]string{"source-address": "127.0.0.42/24,::42/120"} + cert.SignCert(rand.Reader, testSigners["ecdsa"]) + if err := tryAuth(t, clientConfig); err != nil { + t.Errorf("cert login with source-address failed: %v", err) + } + + // disallowed source address + cert.CriticalOptions = map[string]string{"source-address": "127.0.0.42,::42"} + cert.SignCert(rand.Reader, testSigners["ecdsa"]) + if err := tryAuth(t, clientConfig); err == nil { + t.Errorf("cert login with source-address succeeded") + } +} + +func testPermissionsPassing(withPermissions bool, t *testing.T) { + serverConfig := &ServerConfig{ + PublicKeyCallback: func(conn ConnMetadata, key PublicKey) (*Permissions, error) { + if conn.User() == "nopermissions" { + return nil, nil + } + return &Permissions{}, nil + }, + } + serverConfig.AddHostKey(testSigners["rsa"]) + + clientConfig := &ClientConfig{ + Auth: []AuthMethod{ + PublicKeys(testSigners["rsa"]), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + if withPermissions { + clientConfig.User = "permissions" + } else { + clientConfig.User = "nopermissions" + } + + c1, c2, err := netPipe() + if err != nil { + t.Fatalf("netPipe: %v", err) + } + defer c1.Close() + defer c2.Close() + + go NewClientConn(c2, "", clientConfig) + serverConn, err := newServer(c1, serverConfig) + if err != nil { + t.Fatal(err) + } + if p := serverConn.Permissions; (p != nil) != withPermissions { + t.Fatalf("withPermissions is %t, but Permissions object is %#v", withPermissions, p) + } +} + +func TestPermissionsPassing(t *testing.T) { + testPermissionsPassing(true, t) +} + +func TestNoPermissionsPassing(t *testing.T) { + testPermissionsPassing(false, t) +} + +func TestRetryableAuth(t *testing.T) { + n := 0 + passwords := []string{"WRONG1", "WRONG2"} + + config := &ClientConfig{ + User: "testuser", + Auth: []AuthMethod{ + RetryableAuthMethod(PasswordCallback(func() (string, error) { + p := passwords[n] + n++ + return p, nil + }), 2), + PublicKeys(testSigners["rsa"]), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + + if err := tryAuth(t, config); err != nil { + t.Fatalf("unable to dial remote side: %s", err) + } + if n != 2 { + t.Fatalf("Did not try all passwords") + } +} + +func ExampleRetryableAuthMethod() { + user := "testuser" + NumberOfPrompts := 3 + + // Normally this would be a callback that prompts the user to answer the + // provided questions + Cb := func(user, instruction string, questions []string, echos []bool) (answers []string, err error) { + return []string{"answer1", "answer2"}, nil + } + + config := &ClientConfig{ + HostKeyCallback: InsecureIgnoreHostKey(), + User: user, + Auth: []AuthMethod{ + RetryableAuthMethod(KeyboardInteractiveChallenge(Cb), NumberOfPrompts), + }, + } + + host := "mysshserver" + netConn, err := net.Dial("tcp", host) + if err != nil { + log.Fatal(err) + } + + sshConn, _, _, err := NewClientConn(netConn, host, config) + if err != nil { + log.Fatal(err) + } + _ = sshConn +} + +// Test if username is received on server side when NoClientAuth is used +func TestClientAuthNone(t *testing.T) { + user := "testuser" + serverConfig := &ServerConfig{ + NoClientAuth: true, + } + serverConfig.AddHostKey(testSigners["rsa"]) + + clientConfig := &ClientConfig{ + User: user, + HostKeyCallback: InsecureIgnoreHostKey(), + } + + c1, c2, err := netPipe() + if err != nil { + t.Fatalf("netPipe: %v", err) + } + defer c1.Close() + defer c2.Close() + + go NewClientConn(c2, "", clientConfig) + serverConn, err := newServer(c1, serverConfig) + if err != nil { + t.Fatalf("newServer: %v", err) + } + if serverConn.User() != user { + t.Fatalf("server: got %q, want %q", serverConn.User(), user) + } +} + +// Test if authentication attempts are limited on server when MaxAuthTries is set +func TestClientAuthMaxAuthTries(t *testing.T) { + user := "testuser" + + serverConfig := &ServerConfig{ + MaxAuthTries: 2, + PasswordCallback: func(conn ConnMetadata, pass []byte) (*Permissions, error) { + if conn.User() == "testuser" && string(pass) == "right" { + return nil, nil + } + return nil, errors.New("password auth failed") + }, + } + serverConfig.AddHostKey(testSigners["rsa"]) + + expectedErr := fmt.Errorf("ssh: handshake failed: %v", &disconnectMsg{ + Reason: 2, + Message: "too many authentication failures", + }) + + for tries := 2; tries < 4; tries++ { + n := tries + clientConfig := &ClientConfig{ + User: user, + Auth: []AuthMethod{ + RetryableAuthMethod(PasswordCallback(func() (string, error) { + n-- + if n == 0 { + return "right", nil + } + return "wrong", nil + }), tries), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + + c1, c2, err := netPipe() + if err != nil { + t.Fatalf("netPipe: %v", err) + } + defer c1.Close() + defer c2.Close() + + errCh := make(chan error, 1) + + go func() { + _, err := newServer(c1, serverConfig) + errCh <- err + }() + _, _, _, cliErr := NewClientConn(c2, "", clientConfig) + srvErr := <-errCh + + if tries > serverConfig.MaxAuthTries { + if cliErr == nil { + t.Fatalf("client: got no error, want %s", expectedErr) + } else if cliErr.Error() != expectedErr.Error() { + t.Fatalf("client: got %s, want %s", err, expectedErr) + } + var authErr *ServerAuthError + if !errors.As(srvErr, &authErr) { + t.Errorf("expected ServerAuthError, got: %v", srvErr) + } + } else { + if cliErr != nil { + t.Fatalf("client: got %s, want no error", cliErr) + } + } + } +} + +// Test if authentication attempts are correctly limited on server +// when more public keys are provided then MaxAuthTries +func TestClientAuthMaxAuthTriesPublicKey(t *testing.T) { + signers := []Signer{} + for i := 0; i < 6; i++ { + signers = append(signers, testSigners["dsa"]) + } + + validConfig := &ClientConfig{ + User: "testuser", + Auth: []AuthMethod{ + PublicKeys(append([]Signer{testSigners["rsa"]}, signers...)...), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + if err := tryAuth(t, validConfig); err != nil { + t.Fatalf("unable to dial remote side: %s", err) + } + + expectedErr := fmt.Errorf("ssh: handshake failed: %v", &disconnectMsg{ + Reason: 2, + Message: "too many authentication failures", + }) + invalidConfig := &ClientConfig{ + User: "testuser", + Auth: []AuthMethod{ + PublicKeys(append(signers, testSigners["rsa"])...), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + if err := tryAuth(t, invalidConfig); err == nil { + t.Fatalf("client: got no error, want %s", expectedErr) + } else if err.Error() != expectedErr.Error() { + // On Windows we can see a WSAECONNABORTED error + // if the client writes another authentication request + // before the client goroutine reads the disconnection + // message. See issue 50805. + if runtime.GOOS == "windows" && strings.Contains(err.Error(), "wsarecv: An established connection was aborted") { + // OK. + } else { + t.Fatalf("client: got %s, want %s", err, expectedErr) + } + } +} + +// Test whether authentication errors are being properly logged if all +// authentication methods have been exhausted +func TestClientAuthErrorList(t *testing.T) { + publicKeyErr := errors.New("This is an error from PublicKeyCallback") + + clientConfig := &ClientConfig{ + Auth: []AuthMethod{ + PublicKeys(testSigners["rsa"]), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + serverConfig := &ServerConfig{ + PublicKeyCallback: func(_ ConnMetadata, _ PublicKey) (*Permissions, error) { + return nil, publicKeyErr + }, + } + serverConfig.AddHostKey(testSigners["rsa"]) + + c1, c2, err := netPipe() + if err != nil { + t.Fatalf("netPipe: %v", err) + } + defer c1.Close() + defer c2.Close() + + go NewClientConn(c2, "", clientConfig) + _, err = newServer(c1, serverConfig) + if err == nil { + t.Fatal("newServer: got nil, expected errors") + } + + authErrs, ok := err.(*ServerAuthError) + if !ok { + t.Fatalf("errors: got %T, want *ssh.ServerAuthError", err) + } + for i, e := range authErrs.Errors { + switch i { + case 0: + if e != ErrNoAuth { + t.Fatalf("errors: got error %v, want ErrNoAuth", e) + } + case 1: + if e != publicKeyErr { + t.Fatalf("errors: got %v, want %v", e, publicKeyErr) + } + default: + t.Fatalf("errors: got %v, expected 2 errors", authErrs.Errors) + } + } +} + +func TestAuthMethodGSSAPIWithMIC(t *testing.T) { + type testcase struct { + config *ClientConfig + gssConfig *GSSAPIWithMICConfig + clientWantErr string + serverWantErr string + } + testcases := []*testcase{ + { + config: &ClientConfig{ + User: "testuser", + Auth: []AuthMethod{ + GSSAPIWithMICAuthMethod( + &FakeClient{ + exchanges: []*exchange{ + { + outToken: "client-valid-token-1", + }, + { + expectedToken: "server-valid-token-1", + }, + }, + mic: []byte("valid-mic"), + maxRound: 2, + }, "testtarget", + ), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + }, + gssConfig: &GSSAPIWithMICConfig{ + AllowLogin: func(conn ConnMetadata, srcName string) (*Permissions, error) { + if srcName != conn.User()+"@DOMAIN" { + return nil, fmt.Errorf("srcName is %s, conn user is %s", srcName, conn.User()) + } + return nil, nil + }, + Server: &FakeServer{ + exchanges: []*exchange{ + { + outToken: "server-valid-token-1", + expectedToken: "client-valid-token-1", + }, + }, + maxRound: 1, + expectedMIC: []byte("valid-mic"), + srcName: "testuser@DOMAIN", + }, + }, + }, + { + config: &ClientConfig{ + User: "testuser", + Auth: []AuthMethod{ + GSSAPIWithMICAuthMethod( + &FakeClient{ + exchanges: []*exchange{ + { + outToken: "client-valid-token-1", + }, + { + expectedToken: "server-valid-token-1", + }, + }, + mic: []byte("valid-mic"), + maxRound: 2, + }, "testtarget", + ), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + }, + gssConfig: &GSSAPIWithMICConfig{ + AllowLogin: func(conn ConnMetadata, srcName string) (*Permissions, error) { + return nil, fmt.Errorf("user is not allowed to login") + }, + Server: &FakeServer{ + exchanges: []*exchange{ + { + outToken: "server-valid-token-1", + expectedToken: "client-valid-token-1", + }, + }, + maxRound: 1, + expectedMIC: []byte("valid-mic"), + srcName: "testuser@DOMAIN", + }, + }, + serverWantErr: "user is not allowed to login", + clientWantErr: "ssh: handshake failed: ssh: unable to authenticate", + }, + { + config: &ClientConfig{ + User: "testuser", + Auth: []AuthMethod{ + GSSAPIWithMICAuthMethod( + &FakeClient{ + exchanges: []*exchange{ + { + outToken: "client-valid-token-1", + }, + { + expectedToken: "server-valid-token-1", + }, + }, + mic: []byte("valid-mic"), + maxRound: 2, + }, "testtarget", + ), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + }, + gssConfig: &GSSAPIWithMICConfig{ + AllowLogin: func(conn ConnMetadata, srcName string) (*Permissions, error) { + if srcName != conn.User() { + return nil, fmt.Errorf("srcName is %s, conn user is %s", srcName, conn.User()) + } + return nil, nil + }, + Server: &FakeServer{ + exchanges: []*exchange{ + { + outToken: "server-invalid-token-1", + expectedToken: "client-valid-token-1", + }, + }, + maxRound: 1, + expectedMIC: []byte("valid-mic"), + srcName: "testuser@DOMAIN", + }, + }, + clientWantErr: "ssh: handshake failed: got \"server-invalid-token-1\", want token \"server-valid-token-1\"", + }, + { + config: &ClientConfig{ + User: "testuser", + Auth: []AuthMethod{ + GSSAPIWithMICAuthMethod( + &FakeClient{ + exchanges: []*exchange{ + { + outToken: "client-valid-token-1", + }, + { + expectedToken: "server-valid-token-1", + }, + }, + mic: []byte("invalid-mic"), + maxRound: 2, + }, "testtarget", + ), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + }, + gssConfig: &GSSAPIWithMICConfig{ + AllowLogin: func(conn ConnMetadata, srcName string) (*Permissions, error) { + if srcName != conn.User() { + return nil, fmt.Errorf("srcName is %s, conn user is %s", srcName, conn.User()) + } + return nil, nil + }, + Server: &FakeServer{ + exchanges: []*exchange{ + { + outToken: "server-valid-token-1", + expectedToken: "client-valid-token-1", + }, + }, + maxRound: 1, + expectedMIC: []byte("valid-mic"), + srcName: "testuser@DOMAIN", + }, + }, + serverWantErr: "got MICToken \"invalid-mic\", want \"valid-mic\"", + clientWantErr: "ssh: handshake failed: ssh: unable to authenticate", + }, + } + + for i, c := range testcases { + clientErr, serverErrs := tryAuthBothSides(t, c.config, c.gssConfig) + if (c.clientWantErr == "") != (clientErr == nil) { + t.Fatalf("client got %v, want %s, case %d", clientErr, c.clientWantErr, i) + } + if (c.serverWantErr == "") != (len(serverErrs) == 2 && serverErrs[1] == nil || len(serverErrs) == 1) { + t.Fatalf("server got err %v, want %s", serverErrs, c.serverWantErr) + } + if c.clientWantErr != "" { + if clientErr != nil && !strings.Contains(clientErr.Error(), c.clientWantErr) { + t.Fatalf("client got %v, want %s, case %d", clientErr, c.clientWantErr, i) + } + } + found := false + var errStrings []string + if c.serverWantErr != "" { + for _, err := range serverErrs { + found = found || (err != nil && strings.Contains(err.Error(), c.serverWantErr)) + errStrings = append(errStrings, err.Error()) + } + if !found { + t.Errorf("server got error %q, want substring %q, case %d", errStrings, c.serverWantErr, i) + } + } + } +} + +func TestCompatibleAlgoAndSignatures(t *testing.T) { + type testcase struct { + algo string + sigFormat string + compatible bool + } + testcases := []*testcase{ + { + KeyAlgoRSA, + KeyAlgoRSA, + true, + }, + { + KeyAlgoRSA, + KeyAlgoRSASHA256, + true, + }, + { + KeyAlgoRSA, + KeyAlgoRSASHA512, + true, + }, + { + KeyAlgoRSASHA256, + KeyAlgoRSA, + true, + }, + { + KeyAlgoRSASHA512, + KeyAlgoRSA, + true, + }, + { + KeyAlgoRSASHA512, + KeyAlgoRSASHA256, + true, + }, + { + KeyAlgoRSASHA256, + KeyAlgoRSASHA512, + true, + }, + { + KeyAlgoRSASHA512, + KeyAlgoRSASHA512, + true, + }, + { + CertAlgoRSAv01, + KeyAlgoRSA, + true, + }, + { + CertAlgoRSAv01, + KeyAlgoRSASHA256, + true, + }, + { + CertAlgoRSAv01, + KeyAlgoRSASHA512, + true, + }, + { + CertAlgoRSASHA256v01, + KeyAlgoRSASHA512, + true, + }, + { + CertAlgoRSASHA512v01, + KeyAlgoRSASHA512, + true, + }, + { + CertAlgoRSASHA512v01, + KeyAlgoRSASHA256, + true, + }, + { + CertAlgoRSASHA256v01, + CertAlgoRSAv01, + true, + }, + { + CertAlgoRSAv01, + CertAlgoRSASHA512v01, + true, + }, + { + KeyAlgoECDSA256, + KeyAlgoRSA, + false, + }, + { + KeyAlgoECDSA256, + KeyAlgoECDSA521, + false, + }, + { + KeyAlgoECDSA256, + KeyAlgoECDSA256, + true, + }, + { + KeyAlgoECDSA256, + KeyAlgoED25519, + false, + }, + { + KeyAlgoED25519, + KeyAlgoED25519, + true, + }, + } + + for _, c := range testcases { + if isAlgoCompatible(c.algo, c.sigFormat) != c.compatible { + t.Errorf("algorithm %q, signature format %q, expected compatible to be %t", c.algo, c.sigFormat, c.compatible) + } + } +} + +func TestPickSignatureAlgorithm(t *testing.T) { + type testcase struct { + name string + extensions map[string][]byte + } + cases := []testcase{ + { + name: "server with empty server-sig-algs", + extensions: map[string][]byte{ + "server-sig-algs": []byte(``), + }, + }, + { + name: "server with no server-sig-algs", + extensions: nil, + }, + } + for _, c := range cases { + t.Run(c.name, func(t *testing.T) { + signer, ok := testSigners["rsa"].(MultiAlgorithmSigner) + if !ok { + t.Fatalf("rsa test signer does not implement the MultiAlgorithmSigner interface") + } + // The signer supports the public key algorithm which is then returned. + _, algo, err := pickSignatureAlgorithm(signer, c.extensions) + if err != nil { + t.Fatalf("got %v, want no error", err) + } + if algo != signer.PublicKey().Type() { + t.Fatalf("got algo %q, want %q", algo, signer.PublicKey().Type()) + } + // Test a signer that uses a certificate algorithm as the public key + // type. + cert := &Certificate{ + CertType: UserCert, + Key: signer.PublicKey(), + } + cert.SignCert(rand.Reader, signer) + + certSigner, err := NewCertSigner(cert, signer) + if err != nil { + t.Fatalf("error generating cert signer: %v", err) + } + // The signer supports the public key algorithm and the + // public key format is a certificate type so the cerificate + // algorithm matching the key format must be returned + _, algo, err = pickSignatureAlgorithm(certSigner, c.extensions) + if err != nil { + t.Fatalf("got %v, want no error", err) + } + if algo != certSigner.PublicKey().Type() { + t.Fatalf("got algo %q, want %q", algo, certSigner.PublicKey().Type()) + } + signer, err = NewSignerWithAlgorithms(signer.(AlgorithmSigner), []string{KeyAlgoRSASHA512, KeyAlgoRSASHA256}) + if err != nil { + t.Fatalf("unable to create signer with algorithms: %v", err) + } + // The signer does not support the public key algorithm so an error + // is returned. + _, _, err = pickSignatureAlgorithm(signer, c.extensions) + if err == nil { + t.Fatal("got no error, no common public key signature algorithm error expected") + } + }) + } +} + +// configurablePublicKeyCallback is a public key callback that allows to +// configure the signature algorithm and format. This way we can emulate the +// behavior of buggy clients. +type configurablePublicKeyCallback struct { + signer AlgorithmSigner + signatureAlgo string + signatureFormat string +} + +func (cb configurablePublicKeyCallback) method() string { + return "publickey" +} + +func (cb configurablePublicKeyCallback) auth(session []byte, user string, c packetConn, rand io.Reader, extensions map[string][]byte) (authResult, []string, error) { + pub := cb.signer.PublicKey() + + ok, err := validateKey(pub, cb.signatureAlgo, user, c) + if err != nil { + return authFailure, nil, err + } + if !ok { + return authFailure, nil, fmt.Errorf("invalid public key") + } + + pubKey := pub.Marshal() + data := buildDataSignedForAuth(session, userAuthRequestMsg{ + User: user, + Service: serviceSSH, + Method: cb.method(), + }, cb.signatureAlgo, pubKey) + sign, err := cb.signer.SignWithAlgorithm(rand, data, underlyingAlgo(cb.signatureFormat)) + if err != nil { + return authFailure, nil, err + } + + s := Marshal(sign) + sig := make([]byte, stringLength(len(s))) + marshalString(sig, s) + msg := publickeyAuthMsg{ + User: user, + Service: serviceSSH, + Method: cb.method(), + HasSig: true, + Algoname: cb.signatureAlgo, + PubKey: pubKey, + Sig: sig, + } + p := Marshal(&msg) + if err := c.writePacket(p); err != nil { + return authFailure, nil, err + } + var success authResult + success, methods, err := handleAuthResponse(c) + if err != nil { + return authFailure, nil, err + } + if success == authSuccess || !contains(methods, cb.method()) { + return success, methods, err + } + + return authFailure, methods, nil +} + +func TestPublicKeyAndAlgoCompatibility(t *testing.T) { + cert := &Certificate{ + Key: testPublicKeys["rsa"], + ValidBefore: CertTimeInfinity, + CertType: UserCert, + } + cert.SignCert(rand.Reader, testSigners["ecdsa"]) + certSigner, err := NewCertSigner(cert, testSigners["rsa"]) + if err != nil { + t.Fatalf("NewCertSigner: %v", err) + } + + clientConfig := &ClientConfig{ + User: "user", + HostKeyCallback: InsecureIgnoreHostKey(), + Auth: []AuthMethod{ + configurablePublicKeyCallback{ + signer: certSigner.(AlgorithmSigner), + signatureAlgo: KeyAlgoRSASHA256, + signatureFormat: KeyAlgoRSASHA256, + }, + }, + } + if err := tryAuth(t, clientConfig); err == nil { + t.Error("cert login passed with incompatible public key type and algorithm") + } +} + +func TestClientAuthGPGAgentCompat(t *testing.T) { + clientConfig := &ClientConfig{ + User: "testuser", + HostKeyCallback: InsecureIgnoreHostKey(), + Auth: []AuthMethod{ + // algorithm rsa-sha2-512 and signature format ssh-rsa. + configurablePublicKeyCallback{ + signer: testSigners["rsa"].(AlgorithmSigner), + signatureAlgo: KeyAlgoRSASHA512, + signatureFormat: KeyAlgoRSA, + }, + }, + } + if err := tryAuth(t, clientConfig); err != nil { + t.Fatalf("unable to dial remote side: %s", err) + } +} + +func TestCertAuthOpenSSHCompat(t *testing.T) { + cert := &Certificate{ + Key: testPublicKeys["rsa"], + ValidBefore: CertTimeInfinity, + CertType: UserCert, + } + cert.SignCert(rand.Reader, testSigners["ecdsa"]) + certSigner, err := NewCertSigner(cert, testSigners["rsa"]) + if err != nil { + t.Fatalf("NewCertSigner: %v", err) + } + + clientConfig := &ClientConfig{ + User: "user", + HostKeyCallback: InsecureIgnoreHostKey(), + Auth: []AuthMethod{ + // algorithm ssh-rsa-cert-v01@openssh.com and signature format + // rsa-sha2-256. + configurablePublicKeyCallback{ + signer: certSigner.(AlgorithmSigner), + signatureAlgo: CertAlgoRSAv01, + signatureFormat: KeyAlgoRSASHA256, + }, + }, + } + if err := tryAuth(t, clientConfig); err != nil { + t.Fatalf("unable to dial remote side: %s", err) + } +} + +func TestKeyboardInteractiveAuthEarlyFail(t *testing.T) { + const maxAuthTries = 2 + + c1, c2, err := netPipe() + if err != nil { + t.Fatalf("netPipe: %v", err) + } + defer c1.Close() + defer c2.Close() + + // Start testserver + serverConfig := &ServerConfig{ + MaxAuthTries: maxAuthTries, + KeyboardInteractiveCallback: func(c ConnMetadata, + client KeyboardInteractiveChallenge) (*Permissions, error) { + // Fail keyboard-interactive authentication early before + // any prompt is sent to client. + return nil, errors.New("keyboard-interactive auth failed") + }, + PasswordCallback: func(c ConnMetadata, + pass []byte) (*Permissions, error) { + if string(pass) == clientPassword { + return nil, nil + } + return nil, errors.New("password auth failed") + }, + } + serverConfig.AddHostKey(testSigners["rsa"]) + + serverDone := make(chan struct{}) + go func() { + defer func() { serverDone <- struct{}{} }() + conn, chans, reqs, err := NewServerConn(c2, serverConfig) + if err != nil { + return + } + _ = conn.Close() + + discarderDone := make(chan struct{}) + go func() { + defer func() { discarderDone <- struct{}{} }() + DiscardRequests(reqs) + }() + for newChannel := range chans { + newChannel.Reject(Prohibited, + "testserver not accepting requests") + } + + <-discarderDone + }() + + // Connect to testserver, expect KeyboardInteractive() to be not called, + // PasswordCallback() to be called and connection to succeed. + passwordCallbackCalled := false + clientConfig := &ClientConfig{ + User: "testuser", + Auth: []AuthMethod{ + RetryableAuthMethod(KeyboardInteractive(func(name, + instruction string, questions []string, + echos []bool) ([]string, error) { + t.Errorf("unexpected call to KeyboardInteractive()") + return []string{clientPassword}, nil + }), maxAuthTries), + RetryableAuthMethod(PasswordCallback(func() (secret string, + err error) { + t.Logf("PasswordCallback()") + passwordCallbackCalled = true + return clientPassword, nil + }), maxAuthTries), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + + conn, _, _, err := NewClientConn(c1, "", clientConfig) + if err != nil { + t.Errorf("unexpected NewClientConn() error: %v", err) + } + if conn != nil { + conn.Close() + } + + // Wait for server to finish. + <-serverDone + + if !passwordCallbackCalled { + t.Errorf("expected PasswordCallback() to be called") + } +} diff --git a/tempfork/sshtest/ssh/client_test.go b/tempfork/sshtest/ssh/client_test.go new file mode 100644 index 000000000..2621f0ea5 --- /dev/null +++ b/tempfork/sshtest/ssh/client_test.go @@ -0,0 +1,367 @@ +// Copyright 2014 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "bytes" + "crypto/rand" + "errors" + "fmt" + "net" + "strings" + "testing" +) + +func TestClientVersion(t *testing.T) { + for _, tt := range []struct { + name string + version string + multiLine string + wantErr bool + }{ + { + name: "default version", + version: packageVersion, + }, + { + name: "custom version", + version: "SSH-2.0-CustomClientVersionString", + }, + { + name: "good multi line version", + version: packageVersion, + multiLine: strings.Repeat("ignored\r\n", 20), + }, + { + name: "bad multi line version", + version: packageVersion, + multiLine: "bad multi line version", + wantErr: true, + }, + { + name: "long multi line version", + version: packageVersion, + multiLine: strings.Repeat("long multi line version\r\n", 50)[:256], + wantErr: true, + }, + } { + t.Run(tt.name, func(t *testing.T) { + c1, c2, err := netPipe() + if err != nil { + t.Fatalf("netPipe: %v", err) + } + defer c1.Close() + defer c2.Close() + go func() { + if tt.multiLine != "" { + c1.Write([]byte(tt.multiLine)) + } + NewClientConn(c1, "", &ClientConfig{ + ClientVersion: tt.version, + HostKeyCallback: InsecureIgnoreHostKey(), + }) + c1.Close() + }() + conf := &ServerConfig{NoClientAuth: true} + conf.AddHostKey(testSigners["rsa"]) + conn, _, _, err := NewServerConn(c2, conf) + if err == nil == tt.wantErr { + t.Fatalf("got err %v; wantErr %t", err, tt.wantErr) + } + if tt.wantErr { + // Don't verify the version on an expected error. + return + } + if got := string(conn.ClientVersion()); got != tt.version { + t.Fatalf("got %q; want %q", got, tt.version) + } + }) + } +} + +func TestHostKeyCheck(t *testing.T) { + for _, tt := range []struct { + name string + wantError string + key PublicKey + }{ + {"no callback", "must specify HostKeyCallback", nil}, + {"correct key", "", testSigners["rsa"].PublicKey()}, + {"mismatch", "mismatch", testSigners["ecdsa"].PublicKey()}, + } { + c1, c2, err := netPipe() + if err != nil { + t.Fatalf("netPipe: %v", err) + } + defer c1.Close() + defer c2.Close() + serverConf := &ServerConfig{ + NoClientAuth: true, + } + serverConf.AddHostKey(testSigners["rsa"]) + + go NewServerConn(c1, serverConf) + clientConf := ClientConfig{ + User: "user", + } + if tt.key != nil { + clientConf.HostKeyCallback = FixedHostKey(tt.key) + } + + _, _, _, err = NewClientConn(c2, "", &clientConf) + if err != nil { + if tt.wantError == "" || !strings.Contains(err.Error(), tt.wantError) { + t.Errorf("%s: got error %q, missing %q", tt.name, err.Error(), tt.wantError) + } + } else if tt.wantError != "" { + t.Errorf("%s: succeeded, but want error string %q", tt.name, tt.wantError) + } + } +} + +func TestVerifyHostKeySignature(t *testing.T) { + for _, tt := range []struct { + key string + signAlgo string + verifyAlgo string + wantError string + }{ + {"rsa", KeyAlgoRSA, KeyAlgoRSA, ""}, + {"rsa", KeyAlgoRSASHA256, KeyAlgoRSASHA256, ""}, + {"rsa", KeyAlgoRSA, KeyAlgoRSASHA512, `ssh: invalid signature algorithm "ssh-rsa", expected "rsa-sha2-512"`}, + {"ed25519", KeyAlgoED25519, KeyAlgoED25519, ""}, + } { + key := testSigners[tt.key].PublicKey() + s, ok := testSigners[tt.key].(AlgorithmSigner) + if !ok { + t.Fatalf("needed an AlgorithmSigner") + } + sig, err := s.SignWithAlgorithm(rand.Reader, []byte("test"), tt.signAlgo) + if err != nil { + t.Fatalf("couldn't sign: %q", err) + } + + b := bytes.Buffer{} + writeString(&b, []byte(sig.Format)) + writeString(&b, sig.Blob) + + result := kexResult{Signature: b.Bytes(), H: []byte("test")} + + err = verifyHostKeySignature(key, tt.verifyAlgo, &result) + if err != nil { + if tt.wantError == "" || !strings.Contains(err.Error(), tt.wantError) { + t.Errorf("got error %q, expecting %q", err.Error(), tt.wantError) + } + } else if tt.wantError != "" { + t.Errorf("succeeded, but want error string %q", tt.wantError) + } + } +} + +func TestBannerCallback(t *testing.T) { + c1, c2, err := netPipe() + if err != nil { + t.Fatalf("netPipe: %v", err) + } + defer c1.Close() + defer c2.Close() + + serverConf := &ServerConfig{ + PasswordCallback: func(conn ConnMetadata, password []byte) (*Permissions, error) { + return &Permissions{}, nil + }, + BannerCallback: func(conn ConnMetadata) string { + return "Hello World" + }, + } + serverConf.AddHostKey(testSigners["rsa"]) + go NewServerConn(c1, serverConf) + + var receivedBanner string + var bannerCount int + clientConf := ClientConfig{ + Auth: []AuthMethod{ + Password("123"), + }, + User: "user", + HostKeyCallback: InsecureIgnoreHostKey(), + BannerCallback: func(message string) error { + bannerCount++ + receivedBanner = message + return nil + }, + } + + _, _, _, err = NewClientConn(c2, "", &clientConf) + if err != nil { + t.Fatal(err) + } + + if bannerCount != 1 { + t.Errorf("got %d banners; want 1", bannerCount) + } + + expected := "Hello World" + if receivedBanner != expected { + t.Fatalf("got %s; want %s", receivedBanner, expected) + } +} + +func TestNewClientConn(t *testing.T) { + errHostKeyMismatch := errors.New("host key mismatch") + + for _, tt := range []struct { + name string + user string + simulateHostKeyMismatch HostKeyCallback + }{ + { + name: "good user field for ConnMetadata", + user: "testuser", + }, + { + name: "empty user field for ConnMetadata", + user: "", + }, + { + name: "host key mismatch", + user: "testuser", + simulateHostKeyMismatch: func(hostname string, remote net.Addr, key PublicKey) error { + return fmt.Errorf("%w: %s", errHostKeyMismatch, bytes.TrimSpace(MarshalAuthorizedKey(key))) + }, + }, + } { + t.Run(tt.name, func(t *testing.T) { + c1, c2, err := netPipe() + if err != nil { + t.Fatalf("netPipe: %v", err) + } + defer c1.Close() + defer c2.Close() + + serverConf := &ServerConfig{ + PasswordCallback: func(conn ConnMetadata, password []byte) (*Permissions, error) { + return &Permissions{}, nil + }, + } + serverConf.AddHostKey(testSigners["rsa"]) + go NewServerConn(c1, serverConf) + + clientConf := &ClientConfig{ + User: tt.user, + Auth: []AuthMethod{ + Password("testpw"), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + + if tt.simulateHostKeyMismatch != nil { + clientConf.HostKeyCallback = tt.simulateHostKeyMismatch + } + + clientConn, _, _, err := NewClientConn(c2, "", clientConf) + if err != nil { + if tt.simulateHostKeyMismatch != nil && errors.Is(err, errHostKeyMismatch) { + return + } + t.Fatal(err) + } + + if userGot := clientConn.User(); userGot != tt.user { + t.Errorf("got user %q; want user %q", userGot, tt.user) + } + }) + } +} + +func TestUnsupportedAlgorithm(t *testing.T) { + for _, tt := range []struct { + name string + config Config + wantError string + }{ + { + "unsupported KEX", + Config{ + KeyExchanges: []string{"unsupported"}, + }, + "no common algorithm", + }, + { + "unsupported and supported KEXs", + Config{ + KeyExchanges: []string{"unsupported", kexAlgoCurve25519SHA256}, + }, + "", + }, + { + "unsupported cipher", + Config{ + Ciphers: []string{"unsupported"}, + }, + "no common algorithm", + }, + { + "unsupported and supported ciphers", + Config{ + Ciphers: []string{"unsupported", chacha20Poly1305ID}, + }, + "", + }, + { + "unsupported MAC", + Config{ + MACs: []string{"unsupported"}, + // MAC is used for non AAED ciphers. + Ciphers: []string{"aes256-ctr"}, + }, + "no common algorithm", + }, + { + "unsupported and supported MACs", + Config{ + MACs: []string{"unsupported", "hmac-sha2-256-etm@openssh.com"}, + // MAC is used for non AAED ciphers. + Ciphers: []string{"aes256-ctr"}, + }, + "", + }, + } { + t.Run(tt.name, func(t *testing.T) { + c1, c2, err := netPipe() + if err != nil { + t.Fatalf("netPipe: %v", err) + } + defer c1.Close() + defer c2.Close() + + serverConf := &ServerConfig{ + Config: tt.config, + PasswordCallback: func(conn ConnMetadata, password []byte) (*Permissions, error) { + return &Permissions{}, nil + }, + } + serverConf.AddHostKey(testSigners["rsa"]) + go NewServerConn(c1, serverConf) + + clientConf := &ClientConfig{ + User: "testuser", + Config: tt.config, + Auth: []AuthMethod{ + Password("testpw"), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + _, _, _, err = NewClientConn(c2, "", clientConf) + if err != nil { + if tt.wantError == "" || !strings.Contains(err.Error(), tt.wantError) { + t.Errorf("%s: got error %q, missing %q", tt.name, err.Error(), tt.wantError) + } + } else if tt.wantError != "" { + t.Errorf("%s: succeeded, but want error string %q", tt.name, tt.wantError) + } + }) + } +} diff --git a/tempfork/sshtest/ssh/common.go b/tempfork/sshtest/ssh/common.go new file mode 100644 index 000000000..7e9c2cbc6 --- /dev/null +++ b/tempfork/sshtest/ssh/common.go @@ -0,0 +1,476 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "crypto" + "crypto/rand" + "fmt" + "io" + "math" + "sync" + + _ "crypto/sha1" + _ "crypto/sha256" + _ "crypto/sha512" +) + +// These are string constants in the SSH protocol. +const ( + compressionNone = "none" + serviceUserAuth = "ssh-userauth" + serviceSSH = "ssh-connection" +) + +// supportedCiphers lists ciphers we support but might not recommend. +var supportedCiphers = []string{ + "aes128-ctr", "aes192-ctr", "aes256-ctr", + "aes128-gcm@openssh.com", gcm256CipherID, + chacha20Poly1305ID, + "arcfour256", "arcfour128", "arcfour", + aes128cbcID, + tripledescbcID, +} + +// preferredCiphers specifies the default preference for ciphers. +var preferredCiphers = []string{ + "aes128-gcm@openssh.com", gcm256CipherID, + chacha20Poly1305ID, + "aes128-ctr", "aes192-ctr", "aes256-ctr", +} + +// supportedKexAlgos specifies the supported key-exchange algorithms in +// preference order. +var supportedKexAlgos = []string{ + kexAlgoCurve25519SHA256, kexAlgoCurve25519SHA256LibSSH, + // P384 and P521 are not constant-time yet, but since we don't + // reuse ephemeral keys, using them for ECDH should be OK. + kexAlgoECDH256, kexAlgoECDH384, kexAlgoECDH521, + kexAlgoDH14SHA256, kexAlgoDH16SHA512, kexAlgoDH14SHA1, + kexAlgoDH1SHA1, +} + +// serverForbiddenKexAlgos contains key exchange algorithms, that are forbidden +// for the server half. +var serverForbiddenKexAlgos = map[string]struct{}{ + kexAlgoDHGEXSHA1: {}, // server half implementation is only minimal to satisfy the automated tests + kexAlgoDHGEXSHA256: {}, // server half implementation is only minimal to satisfy the automated tests +} + +// preferredKexAlgos specifies the default preference for key-exchange +// algorithms in preference order. The diffie-hellman-group16-sha512 algorithm +// is disabled by default because it is a bit slower than the others. +var preferredKexAlgos = []string{ + kexAlgoCurve25519SHA256, kexAlgoCurve25519SHA256LibSSH, + kexAlgoECDH256, kexAlgoECDH384, kexAlgoECDH521, + kexAlgoDH14SHA256, kexAlgoDH14SHA1, +} + +// supportedHostKeyAlgos specifies the supported host-key algorithms (i.e. methods +// of authenticating servers) in preference order. +var supportedHostKeyAlgos = []string{ + CertAlgoRSASHA256v01, CertAlgoRSASHA512v01, + CertAlgoRSAv01, CertAlgoDSAv01, CertAlgoECDSA256v01, + CertAlgoECDSA384v01, CertAlgoECDSA521v01, CertAlgoED25519v01, + + KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521, + KeyAlgoRSASHA256, KeyAlgoRSASHA512, + KeyAlgoRSA, KeyAlgoDSA, + + KeyAlgoED25519, +} + +// supportedMACs specifies a default set of MAC algorithms in preference order. +// This is based on RFC 4253, section 6.4, but with hmac-md5 variants removed +// because they have reached the end of their useful life. +var supportedMACs = []string{ + "hmac-sha2-256-etm@openssh.com", "hmac-sha2-512-etm@openssh.com", "hmac-sha2-256", "hmac-sha2-512", "hmac-sha1", "hmac-sha1-96", +} + +var supportedCompressions = []string{compressionNone} + +// hashFuncs keeps the mapping of supported signature algorithms to their +// respective hashes needed for signing and verification. +var hashFuncs = map[string]crypto.Hash{ + KeyAlgoRSA: crypto.SHA1, + KeyAlgoRSASHA256: crypto.SHA256, + KeyAlgoRSASHA512: crypto.SHA512, + KeyAlgoDSA: crypto.SHA1, + KeyAlgoECDSA256: crypto.SHA256, + KeyAlgoECDSA384: crypto.SHA384, + KeyAlgoECDSA521: crypto.SHA512, + // KeyAlgoED25519 doesn't pre-hash. + KeyAlgoSKECDSA256: crypto.SHA256, + KeyAlgoSKED25519: crypto.SHA256, +} + +// algorithmsForKeyFormat returns the supported signature algorithms for a given +// public key format (PublicKey.Type), in order of preference. See RFC 8332, +// Section 2. See also the note in sendKexInit on backwards compatibility. +func algorithmsForKeyFormat(keyFormat string) []string { + switch keyFormat { + case KeyAlgoRSA: + return []string{KeyAlgoRSASHA256, KeyAlgoRSASHA512, KeyAlgoRSA} + case CertAlgoRSAv01: + return []string{CertAlgoRSASHA256v01, CertAlgoRSASHA512v01, CertAlgoRSAv01} + default: + return []string{keyFormat} + } +} + +// isRSA returns whether algo is a supported RSA algorithm, including certificate +// algorithms. +func isRSA(algo string) bool { + algos := algorithmsForKeyFormat(KeyAlgoRSA) + return contains(algos, underlyingAlgo(algo)) +} + +func isRSACert(algo string) bool { + _, ok := certKeyAlgoNames[algo] + if !ok { + return false + } + return isRSA(algo) +} + +// supportedPubKeyAuthAlgos specifies the supported client public key +// authentication algorithms. Note that this doesn't include certificate types +// since those use the underlying algorithm. This list is sent to the client if +// it supports the server-sig-algs extension. Order is irrelevant. +var supportedPubKeyAuthAlgos = []string{ + KeyAlgoED25519, + KeyAlgoSKED25519, KeyAlgoSKECDSA256, + KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521, + KeyAlgoRSASHA256, KeyAlgoRSASHA512, KeyAlgoRSA, + KeyAlgoDSA, +} + +// unexpectedMessageError results when the SSH message that we received didn't +// match what we wanted. +func unexpectedMessageError(expected, got uint8) error { + return fmt.Errorf("ssh: unexpected message type %d (expected %d)", got, expected) +} + +// parseError results from a malformed SSH message. +func parseError(tag uint8) error { + return fmt.Errorf("ssh: parse error in message type %d", tag) +} + +func findCommon(what string, client []string, server []string) (common string, err error) { + for _, c := range client { + for _, s := range server { + if c == s { + return c, nil + } + } + } + return "", fmt.Errorf("ssh: no common algorithm for %s; client offered: %v, server offered: %v", what, client, server) +} + +// directionAlgorithms records algorithm choices in one direction (either read or write) +type directionAlgorithms struct { + Cipher string + MAC string + Compression string +} + +// rekeyBytes returns a rekeying intervals in bytes. +func (a *directionAlgorithms) rekeyBytes() int64 { + // According to RFC 4344 block ciphers should rekey after + // 2^(BLOCKSIZE/4) blocks. For all AES flavors BLOCKSIZE is + // 128. + switch a.Cipher { + case "aes128-ctr", "aes192-ctr", "aes256-ctr", gcm128CipherID, gcm256CipherID, aes128cbcID: + return 16 * (1 << 32) + + } + + // For others, stick with RFC 4253 recommendation to rekey after 1 Gb of data. + return 1 << 30 +} + +var aeadCiphers = map[string]bool{ + gcm128CipherID: true, + gcm256CipherID: true, + chacha20Poly1305ID: true, +} + +type algorithms struct { + kex string + hostKey string + w directionAlgorithms + r directionAlgorithms +} + +func findAgreedAlgorithms(isClient bool, clientKexInit, serverKexInit *kexInitMsg) (algs *algorithms, err error) { + result := &algorithms{} + + result.kex, err = findCommon("key exchange", clientKexInit.KexAlgos, serverKexInit.KexAlgos) + if err != nil { + return + } + + result.hostKey, err = findCommon("host key", clientKexInit.ServerHostKeyAlgos, serverKexInit.ServerHostKeyAlgos) + if err != nil { + return + } + + stoc, ctos := &result.w, &result.r + if isClient { + ctos, stoc = stoc, ctos + } + + ctos.Cipher, err = findCommon("client to server cipher", clientKexInit.CiphersClientServer, serverKexInit.CiphersClientServer) + if err != nil { + return + } + + stoc.Cipher, err = findCommon("server to client cipher", clientKexInit.CiphersServerClient, serverKexInit.CiphersServerClient) + if err != nil { + return + } + + if !aeadCiphers[ctos.Cipher] { + ctos.MAC, err = findCommon("client to server MAC", clientKexInit.MACsClientServer, serverKexInit.MACsClientServer) + if err != nil { + return + } + } + + if !aeadCiphers[stoc.Cipher] { + stoc.MAC, err = findCommon("server to client MAC", clientKexInit.MACsServerClient, serverKexInit.MACsServerClient) + if err != nil { + return + } + } + + ctos.Compression, err = findCommon("client to server compression", clientKexInit.CompressionClientServer, serverKexInit.CompressionClientServer) + if err != nil { + return + } + + stoc.Compression, err = findCommon("server to client compression", clientKexInit.CompressionServerClient, serverKexInit.CompressionServerClient) + if err != nil { + return + } + + return result, nil +} + +// If rekeythreshold is too small, we can't make any progress sending +// stuff. +const minRekeyThreshold uint64 = 256 + +// Config contains configuration data common to both ServerConfig and +// ClientConfig. +type Config struct { + // Rand provides the source of entropy for cryptographic + // primitives. If Rand is nil, the cryptographic random reader + // in package crypto/rand will be used. + Rand io.Reader + + // The maximum number of bytes sent or received after which a + // new key is negotiated. It must be at least 256. If + // unspecified, a size suitable for the chosen cipher is used. + RekeyThreshold uint64 + + // The allowed key exchanges algorithms. If unspecified then a default set + // of algorithms is used. Unsupported values are silently ignored. + KeyExchanges []string + + // The allowed cipher algorithms. If unspecified then a sensible default is + // used. Unsupported values are silently ignored. + Ciphers []string + + // The allowed MAC algorithms. If unspecified then a sensible default is + // used. Unsupported values are silently ignored. + MACs []string +} + +// SetDefaults sets sensible values for unset fields in config. This is +// exported for testing: Configs passed to SSH functions are copied and have +// default values set automatically. +func (c *Config) SetDefaults() { + if c.Rand == nil { + c.Rand = rand.Reader + } + if c.Ciphers == nil { + c.Ciphers = preferredCiphers + } + var ciphers []string + for _, c := range c.Ciphers { + if cipherModes[c] != nil { + // Ignore the cipher if we have no cipherModes definition. + ciphers = append(ciphers, c) + } + } + c.Ciphers = ciphers + + if c.KeyExchanges == nil { + c.KeyExchanges = preferredKexAlgos + } + var kexs []string + for _, k := range c.KeyExchanges { + if kexAlgoMap[k] != nil { + // Ignore the KEX if we have no kexAlgoMap definition. + kexs = append(kexs, k) + } + } + c.KeyExchanges = kexs + + if c.MACs == nil { + c.MACs = supportedMACs + } + var macs []string + for _, m := range c.MACs { + if macModes[m] != nil { + // Ignore the MAC if we have no macModes definition. + macs = append(macs, m) + } + } + c.MACs = macs + + if c.RekeyThreshold == 0 { + // cipher specific default + } else if c.RekeyThreshold < minRekeyThreshold { + c.RekeyThreshold = minRekeyThreshold + } else if c.RekeyThreshold >= math.MaxInt64 { + // Avoid weirdness if somebody uses -1 as a threshold. + c.RekeyThreshold = math.MaxInt64 + } +} + +// buildDataSignedForAuth returns the data that is signed in order to prove +// possession of a private key. See RFC 4252, section 7. algo is the advertised +// algorithm, and may be a certificate type. +func buildDataSignedForAuth(sessionID []byte, req userAuthRequestMsg, algo string, pubKey []byte) []byte { + data := struct { + Session []byte + Type byte + User string + Service string + Method string + Sign bool + Algo string + PubKey []byte + }{ + sessionID, + msgUserAuthRequest, + req.User, + req.Service, + req.Method, + true, + algo, + pubKey, + } + return Marshal(data) +} + +func appendU16(buf []byte, n uint16) []byte { + return append(buf, byte(n>>8), byte(n)) +} + +func appendU32(buf []byte, n uint32) []byte { + return append(buf, byte(n>>24), byte(n>>16), byte(n>>8), byte(n)) +} + +func appendU64(buf []byte, n uint64) []byte { + return append(buf, + byte(n>>56), byte(n>>48), byte(n>>40), byte(n>>32), + byte(n>>24), byte(n>>16), byte(n>>8), byte(n)) +} + +func appendInt(buf []byte, n int) []byte { + return appendU32(buf, uint32(n)) +} + +func appendString(buf []byte, s string) []byte { + buf = appendU32(buf, uint32(len(s))) + buf = append(buf, s...) + return buf +} + +func appendBool(buf []byte, b bool) []byte { + if b { + return append(buf, 1) + } + return append(buf, 0) +} + +// newCond is a helper to hide the fact that there is no usable zero +// value for sync.Cond. +func newCond() *sync.Cond { return sync.NewCond(new(sync.Mutex)) } + +// window represents the buffer available to clients +// wishing to write to a channel. +type window struct { + *sync.Cond + win uint32 // RFC 4254 5.2 says the window size can grow to 2^32-1 + writeWaiters int + closed bool +} + +// add adds win to the amount of window available +// for consumers. +func (w *window) add(win uint32) bool { + // a zero sized window adjust is a noop. + if win == 0 { + return true + } + w.L.Lock() + if w.win+win < win { + w.L.Unlock() + return false + } + w.win += win + // It is unusual that multiple goroutines would be attempting to reserve + // window space, but not guaranteed. Use broadcast to notify all waiters + // that additional window is available. + w.Broadcast() + w.L.Unlock() + return true +} + +// close sets the window to closed, so all reservations fail +// immediately. +func (w *window) close() { + w.L.Lock() + w.closed = true + w.Broadcast() + w.L.Unlock() +} + +// reserve reserves win from the available window capacity. +// If no capacity remains, reserve will block. reserve may +// return less than requested. +func (w *window) reserve(win uint32) (uint32, error) { + var err error + w.L.Lock() + w.writeWaiters++ + w.Broadcast() + for w.win == 0 && !w.closed { + w.Wait() + } + w.writeWaiters-- + if w.win < win { + win = w.win + } + w.win -= win + if w.closed { + err = io.EOF + } + w.L.Unlock() + return win, err +} + +// waitWriterBlocked waits until some goroutine is blocked for further +// writes. It is used in tests only. +func (w *window) waitWriterBlocked() { + w.Cond.L.Lock() + for w.writeWaiters == 0 { + w.Cond.Wait() + } + w.Cond.L.Unlock() +} diff --git a/tempfork/sshtest/ssh/common_test.go b/tempfork/sshtest/ssh/common_test.go new file mode 100644 index 000000000..a7beee8e8 --- /dev/null +++ b/tempfork/sshtest/ssh/common_test.go @@ -0,0 +1,176 @@ +// Copyright 2019 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "reflect" + "testing" +) + +func TestFindAgreedAlgorithms(t *testing.T) { + initKex := func(k *kexInitMsg) { + if k.KexAlgos == nil { + k.KexAlgos = []string{"kex1"} + } + if k.ServerHostKeyAlgos == nil { + k.ServerHostKeyAlgos = []string{"hostkey1"} + } + if k.CiphersClientServer == nil { + k.CiphersClientServer = []string{"cipher1"} + + } + if k.CiphersServerClient == nil { + k.CiphersServerClient = []string{"cipher1"} + + } + if k.MACsClientServer == nil { + k.MACsClientServer = []string{"mac1"} + + } + if k.MACsServerClient == nil { + k.MACsServerClient = []string{"mac1"} + + } + if k.CompressionClientServer == nil { + k.CompressionClientServer = []string{"compression1"} + + } + if k.CompressionServerClient == nil { + k.CompressionServerClient = []string{"compression1"} + + } + if k.LanguagesClientServer == nil { + k.LanguagesClientServer = []string{"language1"} + + } + if k.LanguagesServerClient == nil { + k.LanguagesServerClient = []string{"language1"} + + } + } + + initDirAlgs := func(a *directionAlgorithms) { + if a.Cipher == "" { + a.Cipher = "cipher1" + } + if a.MAC == "" { + a.MAC = "mac1" + } + if a.Compression == "" { + a.Compression = "compression1" + } + } + + initAlgs := func(a *algorithms) { + if a.kex == "" { + a.kex = "kex1" + } + if a.hostKey == "" { + a.hostKey = "hostkey1" + } + initDirAlgs(&a.r) + initDirAlgs(&a.w) + } + + type testcase struct { + name string + clientIn, serverIn kexInitMsg + wantClient, wantServer algorithms + wantErr bool + } + + cases := []testcase{ + { + name: "standard", + }, + + { + name: "no common hostkey", + serverIn: kexInitMsg{ + ServerHostKeyAlgos: []string{"hostkey2"}, + }, + wantErr: true, + }, + + { + name: "no common kex", + serverIn: kexInitMsg{ + KexAlgos: []string{"kex2"}, + }, + wantErr: true, + }, + + { + name: "no common cipher", + serverIn: kexInitMsg{ + CiphersClientServer: []string{"cipher2"}, + }, + wantErr: true, + }, + + { + name: "client decides cipher", + serverIn: kexInitMsg{ + CiphersClientServer: []string{"cipher1", "cipher2"}, + CiphersServerClient: []string{"cipher2", "cipher3"}, + }, + clientIn: kexInitMsg{ + CiphersClientServer: []string{"cipher2", "cipher1"}, + CiphersServerClient: []string{"cipher3", "cipher2"}, + }, + wantClient: algorithms{ + r: directionAlgorithms{ + Cipher: "cipher3", + }, + w: directionAlgorithms{ + Cipher: "cipher2", + }, + }, + wantServer: algorithms{ + w: directionAlgorithms{ + Cipher: "cipher3", + }, + r: directionAlgorithms{ + Cipher: "cipher2", + }, + }, + }, + + // TODO(hanwen): fix and add tests for AEAD ignoring + // the MACs field + } + + for i := range cases { + initKex(&cases[i].clientIn) + initKex(&cases[i].serverIn) + initAlgs(&cases[i].wantClient) + initAlgs(&cases[i].wantServer) + } + + for _, c := range cases { + t.Run(c.name, func(t *testing.T) { + serverAlgs, serverErr := findAgreedAlgorithms(false, &c.clientIn, &c.serverIn) + clientAlgs, clientErr := findAgreedAlgorithms(true, &c.clientIn, &c.serverIn) + + serverHasErr := serverErr != nil + clientHasErr := clientErr != nil + if c.wantErr != serverHasErr || c.wantErr != clientHasErr { + t.Fatalf("got client/server error (%v, %v), want hasError %v", + clientErr, serverErr, c.wantErr) + + } + if c.wantErr { + return + } + + if !reflect.DeepEqual(serverAlgs, &c.wantServer) { + t.Errorf("server: got algs %#v, want %#v", serverAlgs, &c.wantServer) + } + if !reflect.DeepEqual(clientAlgs, &c.wantClient) { + t.Errorf("server: got algs %#v, want %#v", clientAlgs, &c.wantClient) + } + }) + } +} diff --git a/tempfork/sshtest/ssh/connection.go b/tempfork/sshtest/ssh/connection.go new file mode 100644 index 000000000..8f345ee92 --- /dev/null +++ b/tempfork/sshtest/ssh/connection.go @@ -0,0 +1,143 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "fmt" + "net" +) + +// OpenChannelError is returned if the other side rejects an +// OpenChannel request. +type OpenChannelError struct { + Reason RejectionReason + Message string +} + +func (e *OpenChannelError) Error() string { + return fmt.Sprintf("ssh: rejected: %s (%s)", e.Reason, e.Message) +} + +// ConnMetadata holds metadata for the connection. +type ConnMetadata interface { + // User returns the user ID for this connection. + User() string + + // SessionID returns the session hash, also denoted by H. + SessionID() []byte + + // ClientVersion returns the client's version string as hashed + // into the session ID. + ClientVersion() []byte + + // ServerVersion returns the server's version string as hashed + // into the session ID. + ServerVersion() []byte + + // RemoteAddr returns the remote address for this connection. + RemoteAddr() net.Addr + + // LocalAddr returns the local address for this connection. + LocalAddr() net.Addr +} + +// Conn represents an SSH connection for both server and client roles. +// Conn is the basis for implementing an application layer, such +// as ClientConn, which implements the traditional shell access for +// clients. +type Conn interface { + ConnMetadata + + // SendRequest sends a global request, and returns the + // reply. If wantReply is true, it returns the response status + // and payload. See also RFC 4254, section 4. + SendRequest(name string, wantReply bool, payload []byte) (bool, []byte, error) + + // OpenChannel tries to open an channel. If the request is + // rejected, it returns *OpenChannelError. On success it returns + // the SSH Channel and a Go channel for incoming, out-of-band + // requests. The Go channel must be serviced, or the + // connection will hang. + OpenChannel(name string, data []byte) (Channel, <-chan *Request, error) + + // Close closes the underlying network connection + Close() error + + // Wait blocks until the connection has shut down, and returns the + // error causing the shutdown. + Wait() error + + // TODO(hanwen): consider exposing: + // RequestKeyChange + // Disconnect +} + +// DiscardRequests consumes and rejects all requests from the +// passed-in channel. +func DiscardRequests(in <-chan *Request) { + for req := range in { + if req.WantReply { + req.Reply(false, nil) + } + } +} + +// A connection represents an incoming connection. +type connection struct { + transport *handshakeTransport + sshConn + + // The connection protocol. + *mux +} + +func (c *connection) Close() error { + return c.sshConn.conn.Close() +} + +// sshConn provides net.Conn metadata, but disallows direct reads and +// writes. +type sshConn struct { + conn net.Conn + + user string + sessionID []byte + clientVersion []byte + serverVersion []byte +} + +func dup(src []byte) []byte { + dst := make([]byte, len(src)) + copy(dst, src) + return dst +} + +func (c *sshConn) User() string { + return c.user +} + +func (c *sshConn) RemoteAddr() net.Addr { + return c.conn.RemoteAddr() +} + +func (c *sshConn) Close() error { + return c.conn.Close() +} + +func (c *sshConn) LocalAddr() net.Addr { + return c.conn.LocalAddr() +} + +func (c *sshConn) SessionID() []byte { + return dup(c.sessionID) +} + +func (c *sshConn) ClientVersion() []byte { + return dup(c.clientVersion) +} + +func (c *sshConn) ServerVersion() []byte { + return dup(c.serverVersion) +} diff --git a/tempfork/sshtest/ssh/doc.go b/tempfork/sshtest/ssh/doc.go new file mode 100644 index 000000000..f5d352fe3 --- /dev/null +++ b/tempfork/sshtest/ssh/doc.go @@ -0,0 +1,23 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +/* +Package ssh implements an SSH client and server. + +SSH is a transport security protocol, an authentication protocol and a +family of application protocols. The most typical application level +protocol is a remote shell and this is specifically implemented. However, +the multiplexed nature of SSH is exposed to users that wish to support +others. + +References: + + [PROTOCOL]: https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/PROTOCOL?rev=HEAD + [PROTOCOL.certkeys]: http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/PROTOCOL.certkeys?rev=HEAD + [SSH-PARAMETERS]: http://www.iana.org/assignments/ssh-parameters/ssh-parameters.xml#ssh-parameters-1 + +This package does not fall under the stability promise of the Go language itself, +so its API may be changed when pressing needs arise. +*/ +package ssh diff --git a/tempfork/sshtest/ssh/example_test.go b/tempfork/sshtest/ssh/example_test.go new file mode 100644 index 000000000..97b3b6aba --- /dev/null +++ b/tempfork/sshtest/ssh/example_test.go @@ -0,0 +1,400 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh_test + +import ( + "bufio" + "bytes" + "crypto/rand" + "crypto/rsa" + "fmt" + "log" + "net" + "net/http" + "os" + "path/filepath" + "strings" + "sync" + + "golang.org/x/crypto/ssh" + "golang.org/x/crypto/ssh/terminal" +) + +func ExampleNewServerConn() { + // Public key authentication is done by comparing + // the public key of a received connection + // with the entries in the authorized_keys file. + authorizedKeysBytes, err := os.ReadFile("authorized_keys") + if err != nil { + log.Fatalf("Failed to load authorized_keys, err: %v", err) + } + + authorizedKeysMap := map[string]bool{} + for len(authorizedKeysBytes) > 0 { + pubKey, _, _, rest, err := ssh.ParseAuthorizedKey(authorizedKeysBytes) + if err != nil { + log.Fatal(err) + } + + authorizedKeysMap[string(pubKey.Marshal())] = true + authorizedKeysBytes = rest + } + + // An SSH server is represented by a ServerConfig, which holds + // certificate details and handles authentication of ServerConns. + config := &ssh.ServerConfig{ + // Remove to disable password auth. + PasswordCallback: func(c ssh.ConnMetadata, pass []byte) (*ssh.Permissions, error) { + // Should use constant-time compare (or better, salt+hash) in + // a production setting. + if c.User() == "testuser" && string(pass) == "tiger" { + return nil, nil + } + return nil, fmt.Errorf("password rejected for %q", c.User()) + }, + + // Remove to disable public key auth. + PublicKeyCallback: func(c ssh.ConnMetadata, pubKey ssh.PublicKey) (*ssh.Permissions, error) { + if authorizedKeysMap[string(pubKey.Marshal())] { + return &ssh.Permissions{ + // Record the public key used for authentication. + Extensions: map[string]string{ + "pubkey-fp": ssh.FingerprintSHA256(pubKey), + }, + }, nil + } + return nil, fmt.Errorf("unknown public key for %q", c.User()) + }, + } + + privateBytes, err := os.ReadFile("id_rsa") + if err != nil { + log.Fatal("Failed to load private key: ", err) + } + + private, err := ssh.ParsePrivateKey(privateBytes) + if err != nil { + log.Fatal("Failed to parse private key: ", err) + } + config.AddHostKey(private) + + // Once a ServerConfig has been configured, connections can be + // accepted. + listener, err := net.Listen("tcp", "0.0.0.0:2022") + if err != nil { + log.Fatal("failed to listen for connection: ", err) + } + nConn, err := listener.Accept() + if err != nil { + log.Fatal("failed to accept incoming connection: ", err) + } + + // Before use, a handshake must be performed on the incoming + // net.Conn. + conn, chans, reqs, err := ssh.NewServerConn(nConn, config) + if err != nil { + log.Fatal("failed to handshake: ", err) + } + log.Printf("logged in with key %s", conn.Permissions.Extensions["pubkey-fp"]) + + var wg sync.WaitGroup + defer wg.Wait() + + // The incoming Request channel must be serviced. + wg.Add(1) + go func() { + ssh.DiscardRequests(reqs) + wg.Done() + }() + + // Service the incoming Channel channel. + for newChannel := range chans { + // Channels have a type, depending on the application level + // protocol intended. In the case of a shell, the type is + // "session" and ServerShell may be used to present a simple + // terminal interface. + if newChannel.ChannelType() != "session" { + newChannel.Reject(ssh.UnknownChannelType, "unknown channel type") + continue + } + channel, requests, err := newChannel.Accept() + if err != nil { + log.Fatalf("Could not accept channel: %v", err) + } + + // Sessions have out-of-band requests such as "shell", + // "pty-req" and "env". Here we handle only the + // "shell" request. + wg.Add(1) + go func(in <-chan *ssh.Request) { + for req := range in { + req.Reply(req.Type == "shell", nil) + } + wg.Done() + }(requests) + + term := terminal.NewTerminal(channel, "> ") + + wg.Add(1) + go func() { + defer func() { + channel.Close() + wg.Done() + }() + for { + line, err := term.ReadLine() + if err != nil { + break + } + fmt.Println(line) + } + }() + } +} + +func ExampleServerConfig_AddHostKey() { + // Minimal ServerConfig supporting only password authentication. + config := &ssh.ServerConfig{ + PasswordCallback: func(c ssh.ConnMetadata, pass []byte) (*ssh.Permissions, error) { + // Should use constant-time compare (or better, salt+hash) in + // a production setting. + if c.User() == "testuser" && string(pass) == "tiger" { + return nil, nil + } + return nil, fmt.Errorf("password rejected for %q", c.User()) + }, + } + + privateBytes, err := os.ReadFile("id_rsa") + if err != nil { + log.Fatal("Failed to load private key: ", err) + } + + private, err := ssh.ParsePrivateKey(privateBytes) + if err != nil { + log.Fatal("Failed to parse private key: ", err) + } + // Restrict host key algorithms to disable ssh-rsa. + signer, err := ssh.NewSignerWithAlgorithms(private.(ssh.AlgorithmSigner), []string{ssh.KeyAlgoRSASHA256, ssh.KeyAlgoRSASHA512}) + if err != nil { + log.Fatal("Failed to create private key with restricted algorithms: ", err) + } + config.AddHostKey(signer) +} + +func ExampleClientConfig_HostKeyCallback() { + // Every client must provide a host key check. Here is a + // simple-minded parse of OpenSSH's known_hosts file + host := "hostname" + file, err := os.Open(filepath.Join(os.Getenv("HOME"), ".ssh", "known_hosts")) + if err != nil { + log.Fatal(err) + } + defer file.Close() + + scanner := bufio.NewScanner(file) + var hostKey ssh.PublicKey + for scanner.Scan() { + fields := strings.Split(scanner.Text(), " ") + if len(fields) != 3 { + continue + } + if strings.Contains(fields[0], host) { + var err error + hostKey, _, _, _, err = ssh.ParseAuthorizedKey(scanner.Bytes()) + if err != nil { + log.Fatalf("error parsing %q: %v", fields[2], err) + } + break + } + } + + if hostKey == nil { + log.Fatalf("no hostkey for %s", host) + } + + config := ssh.ClientConfig{ + User: os.Getenv("USER"), + HostKeyCallback: ssh.FixedHostKey(hostKey), + } + + _, err = ssh.Dial("tcp", host+":22", &config) + log.Println(err) +} + +func ExampleDial() { + var hostKey ssh.PublicKey + // An SSH client is represented with a ClientConn. + // + // To authenticate with the remote server you must pass at least one + // implementation of AuthMethod via the Auth field in ClientConfig, + // and provide a HostKeyCallback. + config := &ssh.ClientConfig{ + User: "username", + Auth: []ssh.AuthMethod{ + ssh.Password("yourpassword"), + }, + HostKeyCallback: ssh.FixedHostKey(hostKey), + } + client, err := ssh.Dial("tcp", "yourserver.com:22", config) + if err != nil { + log.Fatal("Failed to dial: ", err) + } + defer client.Close() + + // Each ClientConn can support multiple interactive sessions, + // represented by a Session. + session, err := client.NewSession() + if err != nil { + log.Fatal("Failed to create session: ", err) + } + defer session.Close() + + // Once a Session is created, you can execute a single command on + // the remote side using the Run method. + var b bytes.Buffer + session.Stdout = &b + if err := session.Run("/usr/bin/whoami"); err != nil { + log.Fatal("Failed to run: " + err.Error()) + } + fmt.Println(b.String()) +} + +func ExamplePublicKeys() { + var hostKey ssh.PublicKey + // A public key may be used to authenticate against the remote + // server by using an unencrypted PEM-encoded private key file. + // + // If you have an encrypted private key, the crypto/x509 package + // can be used to decrypt it. + key, err := os.ReadFile("/home/user/.ssh/id_rsa") + if err != nil { + log.Fatalf("unable to read private key: %v", err) + } + + // Create the Signer for this private key. + signer, err := ssh.ParsePrivateKey(key) + if err != nil { + log.Fatalf("unable to parse private key: %v", err) + } + + config := &ssh.ClientConfig{ + User: "user", + Auth: []ssh.AuthMethod{ + // Use the PublicKeys method for remote authentication. + ssh.PublicKeys(signer), + }, + HostKeyCallback: ssh.FixedHostKey(hostKey), + } + + // Connect to the remote server and perform the SSH handshake. + client, err := ssh.Dial("tcp", "host.com:22", config) + if err != nil { + log.Fatalf("unable to connect: %v", err) + } + defer client.Close() +} + +func ExampleClient_Listen() { + var hostKey ssh.PublicKey + config := &ssh.ClientConfig{ + User: "username", + Auth: []ssh.AuthMethod{ + ssh.Password("password"), + }, + HostKeyCallback: ssh.FixedHostKey(hostKey), + } + // Dial your ssh server. + conn, err := ssh.Dial("tcp", "localhost:22", config) + if err != nil { + log.Fatal("unable to connect: ", err) + } + defer conn.Close() + + // Request the remote side to open port 8080 on all interfaces. + l, err := conn.Listen("tcp", "0.0.0.0:8080") + if err != nil { + log.Fatal("unable to register tcp forward: ", err) + } + defer l.Close() + + // Serve HTTP with your SSH server acting as a reverse proxy. + http.Serve(l, http.HandlerFunc(func(resp http.ResponseWriter, req *http.Request) { + fmt.Fprintf(resp, "Hello world!\n") + })) +} + +func ExampleSession_RequestPty() { + var hostKey ssh.PublicKey + // Create client config + config := &ssh.ClientConfig{ + User: "username", + Auth: []ssh.AuthMethod{ + ssh.Password("password"), + }, + HostKeyCallback: ssh.FixedHostKey(hostKey), + } + // Connect to ssh server + conn, err := ssh.Dial("tcp", "localhost:22", config) + if err != nil { + log.Fatal("unable to connect: ", err) + } + defer conn.Close() + // Create a session + session, err := conn.NewSession() + if err != nil { + log.Fatal("unable to create session: ", err) + } + defer session.Close() + // Set up terminal modes + modes := ssh.TerminalModes{ + ssh.ECHO: 0, // disable echoing + ssh.TTY_OP_ISPEED: 14400, // input speed = 14.4kbaud + ssh.TTY_OP_OSPEED: 14400, // output speed = 14.4kbaud + } + // Request pseudo terminal + if err := session.RequestPty("xterm", 40, 80, modes); err != nil { + log.Fatal("request for pseudo terminal failed: ", err) + } + // Start remote shell + if err := session.Shell(); err != nil { + log.Fatal("failed to start shell: ", err) + } +} + +func ExampleCertificate_SignCert() { + // Sign a certificate with a specific algorithm. + privateKey, err := rsa.GenerateKey(rand.Reader, 3072) + if err != nil { + log.Fatal("unable to generate RSA key: ", err) + } + publicKey, err := ssh.NewPublicKey(&privateKey.PublicKey) + if err != nil { + log.Fatal("unable to get RSA public key: ", err) + } + caKey, err := rsa.GenerateKey(rand.Reader, 3072) + if err != nil { + log.Fatal("unable to generate CA key: ", err) + } + signer, err := ssh.NewSignerFromKey(caKey) + if err != nil { + log.Fatal("unable to generate signer from key: ", err) + } + mas, err := ssh.NewSignerWithAlgorithms(signer.(ssh.AlgorithmSigner), []string{ssh.KeyAlgoRSASHA256}) + if err != nil { + log.Fatal("unable to create signer with algorithms: ", err) + } + certificate := ssh.Certificate{ + Key: publicKey, + CertType: ssh.UserCert, + } + if err := certificate.SignCert(rand.Reader, mas); err != nil { + log.Fatal("unable to sign certificate: ", err) + } + // Save the public key to a file and check that rsa-sha-256 is used for + // signing: + // ssh-keygen -L -f + fmt.Println(string(ssh.MarshalAuthorizedKey(&certificate))) +} diff --git a/tempfork/sshtest/ssh/handshake.go b/tempfork/sshtest/ssh/handshake.go new file mode 100644 index 000000000..fef687db0 --- /dev/null +++ b/tempfork/sshtest/ssh/handshake.go @@ -0,0 +1,816 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "crypto/rand" + "errors" + "fmt" + "io" + "log" + "net" + "strings" + "sync" +) + +// debugHandshake, if set, prints messages sent and received. Key +// exchange messages are printed as if DH were used, so the debug +// messages are wrong when using ECDH. +const debugHandshake = false + +// chanSize sets the amount of buffering SSH connections. This is +// primarily for testing: setting chanSize=0 uncovers deadlocks more +// quickly. +const chanSize = 16 + +// keyingTransport is a packet based transport that supports key +// changes. It need not be thread-safe. It should pass through +// msgNewKeys in both directions. +type keyingTransport interface { + packetConn + + // prepareKeyChange sets up a key change. The key change for a + // direction will be effected if a msgNewKeys message is sent + // or received. + prepareKeyChange(*algorithms, *kexResult) error + + // setStrictMode sets the strict KEX mode, notably triggering + // sequence number resets on sending or receiving msgNewKeys. + // If the sequence number is already > 1 when setStrictMode + // is called, an error is returned. + setStrictMode() error + + // setInitialKEXDone indicates to the transport that the initial key exchange + // was completed + setInitialKEXDone() +} + +// handshakeTransport implements rekeying on top of a keyingTransport +// and offers a thread-safe writePacket() interface. +type handshakeTransport struct { + conn keyingTransport + config *Config + + serverVersion []byte + clientVersion []byte + + // hostKeys is non-empty if we are the server. In that case, + // it contains all host keys that can be used to sign the + // connection. + hostKeys []Signer + + // publicKeyAuthAlgorithms is non-empty if we are the server. In that case, + // it contains the supported client public key authentication algorithms. + publicKeyAuthAlgorithms []string + + // hostKeyAlgorithms is non-empty if we are the client. In that case, + // we accept these key types from the server as host key. + hostKeyAlgorithms []string + + // On read error, incoming is closed, and readError is set. + incoming chan []byte + readError error + + mu sync.Mutex + writeError error + sentInitPacket []byte + sentInitMsg *kexInitMsg + pendingPackets [][]byte // Used when a key exchange is in progress. + writePacketsLeft uint32 + writeBytesLeft int64 + userAuthComplete bool // whether the user authentication phase is complete + + // If the read loop wants to schedule a kex, it pings this + // channel, and the write loop will send out a kex + // message. + requestKex chan struct{} + + // If the other side requests or confirms a kex, its kexInit + // packet is sent here for the write loop to find it. + startKex chan *pendingKex + kexLoopDone chan struct{} // closed (with writeError non-nil) when kexLoop exits + + // data for host key checking + hostKeyCallback HostKeyCallback + dialAddress string + remoteAddr net.Addr + + // bannerCallback is non-empty if we are the client and it has been set in + // ClientConfig. In that case it is called during the user authentication + // dance to handle a custom server's message. + bannerCallback BannerCallback + + // Algorithms agreed in the last key exchange. + algorithms *algorithms + + // Counters exclusively owned by readLoop. + readPacketsLeft uint32 + readBytesLeft int64 + + // The session ID or nil if first kex did not complete yet. + sessionID []byte + + // strictMode indicates if the other side of the handshake indicated + // that we should be following the strict KEX protocol restrictions. + strictMode bool +} + +type pendingKex struct { + otherInit []byte + done chan error +} + +func newHandshakeTransport(conn keyingTransport, config *Config, clientVersion, serverVersion []byte) *handshakeTransport { + t := &handshakeTransport{ + conn: conn, + serverVersion: serverVersion, + clientVersion: clientVersion, + incoming: make(chan []byte, chanSize), + requestKex: make(chan struct{}, 1), + startKex: make(chan *pendingKex), + kexLoopDone: make(chan struct{}), + + config: config, + } + t.resetReadThresholds() + t.resetWriteThresholds() + + // We always start with a mandatory key exchange. + t.requestKex <- struct{}{} + return t +} + +func newClientTransport(conn keyingTransport, clientVersion, serverVersion []byte, config *ClientConfig, dialAddr string, addr net.Addr) *handshakeTransport { + t := newHandshakeTransport(conn, &config.Config, clientVersion, serverVersion) + t.dialAddress = dialAddr + t.remoteAddr = addr + t.hostKeyCallback = config.HostKeyCallback + t.bannerCallback = config.BannerCallback + if config.HostKeyAlgorithms != nil { + t.hostKeyAlgorithms = config.HostKeyAlgorithms + } else { + t.hostKeyAlgorithms = supportedHostKeyAlgos + } + go t.readLoop() + go t.kexLoop() + return t +} + +func newServerTransport(conn keyingTransport, clientVersion, serverVersion []byte, config *ServerConfig) *handshakeTransport { + t := newHandshakeTransport(conn, &config.Config, clientVersion, serverVersion) + t.hostKeys = config.hostKeys + t.publicKeyAuthAlgorithms = config.PublicKeyAuthAlgorithms + go t.readLoop() + go t.kexLoop() + return t +} + +func (t *handshakeTransport) getSessionID() []byte { + return t.sessionID +} + +// waitSession waits for the session to be established. This should be +// the first thing to call after instantiating handshakeTransport. +func (t *handshakeTransport) waitSession() error { + p, err := t.readPacket() + if err != nil { + return err + } + if p[0] != msgNewKeys { + return fmt.Errorf("ssh: first packet should be msgNewKeys") + } + + return nil +} + +func (t *handshakeTransport) id() string { + if len(t.hostKeys) > 0 { + return "server" + } + return "client" +} + +func (t *handshakeTransport) printPacket(p []byte, write bool) { + action := "got" + if write { + action = "sent" + } + + if p[0] == msgChannelData || p[0] == msgChannelExtendedData { + log.Printf("%s %s data (packet %d bytes)", t.id(), action, len(p)) + } else { + msg, err := decode(p) + log.Printf("%s %s %T %v (%v)", t.id(), action, msg, msg, err) + } +} + +func (t *handshakeTransport) readPacket() ([]byte, error) { + p, ok := <-t.incoming + if !ok { + return nil, t.readError + } + return p, nil +} + +func (t *handshakeTransport) readLoop() { + first := true + for { + p, err := t.readOnePacket(first) + first = false + if err != nil { + t.readError = err + close(t.incoming) + break + } + // If this is the first kex, and strict KEX mode is enabled, + // we don't ignore any messages, as they may be used to manipulate + // the packet sequence numbers. + if !(t.sessionID == nil && t.strictMode) && (p[0] == msgIgnore || p[0] == msgDebug) { + continue + } + t.incoming <- p + } + + // Stop writers too. + t.recordWriteError(t.readError) + + // Unblock the writer should it wait for this. + close(t.startKex) + + // Don't close t.requestKex; it's also written to from writePacket. +} + +func (t *handshakeTransport) pushPacket(p []byte) error { + if debugHandshake { + t.printPacket(p, true) + } + return t.conn.writePacket(p) +} + +func (t *handshakeTransport) getWriteError() error { + t.mu.Lock() + defer t.mu.Unlock() + return t.writeError +} + +func (t *handshakeTransport) recordWriteError(err error) { + t.mu.Lock() + defer t.mu.Unlock() + if t.writeError == nil && err != nil { + t.writeError = err + } +} + +func (t *handshakeTransport) requestKeyExchange() { + select { + case t.requestKex <- struct{}{}: + default: + // something already requested a kex, so do nothing. + } +} + +func (t *handshakeTransport) resetWriteThresholds() { + t.writePacketsLeft = packetRekeyThreshold + if t.config.RekeyThreshold > 0 { + t.writeBytesLeft = int64(t.config.RekeyThreshold) + } else if t.algorithms != nil { + t.writeBytesLeft = t.algorithms.w.rekeyBytes() + } else { + t.writeBytesLeft = 1 << 30 + } +} + +func (t *handshakeTransport) kexLoop() { + +write: + for t.getWriteError() == nil { + var request *pendingKex + var sent bool + + for request == nil || !sent { + var ok bool + select { + case request, ok = <-t.startKex: + if !ok { + break write + } + case <-t.requestKex: + break + } + + if !sent { + if err := t.sendKexInit(); err != nil { + t.recordWriteError(err) + break + } + sent = true + } + } + + if err := t.getWriteError(); err != nil { + if request != nil { + request.done <- err + } + break + } + + // We're not servicing t.requestKex, but that is OK: + // we never block on sending to t.requestKex. + + // We're not servicing t.startKex, but the remote end + // has just sent us a kexInitMsg, so it can't send + // another key change request, until we close the done + // channel on the pendingKex request. + + err := t.enterKeyExchange(request.otherInit) + + t.mu.Lock() + t.writeError = err + t.sentInitPacket = nil + t.sentInitMsg = nil + + t.resetWriteThresholds() + + // we have completed the key exchange. Since the + // reader is still blocked, it is safe to clear out + // the requestKex channel. This avoids the situation + // where: 1) we consumed our own request for the + // initial kex, and 2) the kex from the remote side + // caused another send on the requestKex channel, + clear: + for { + select { + case <-t.requestKex: + // + default: + break clear + } + } + + request.done <- t.writeError + + // kex finished. Push packets that we received while + // the kex was in progress. Don't look at t.startKex + // and don't increment writtenSinceKex: if we trigger + // another kex while we are still busy with the last + // one, things will become very confusing. + for _, p := range t.pendingPackets { + t.writeError = t.pushPacket(p) + if t.writeError != nil { + break + } + } + t.pendingPackets = t.pendingPackets[:0] + t.mu.Unlock() + } + + // Unblock reader. + t.conn.Close() + + // drain startKex channel. We don't service t.requestKex + // because nobody does blocking sends there. + for request := range t.startKex { + request.done <- t.getWriteError() + } + + // Mark that the loop is done so that Close can return. + close(t.kexLoopDone) +} + +// The protocol uses uint32 for packet counters, so we can't let them +// reach 1<<32. We will actually read and write more packets than +// this, though: the other side may send more packets, and after we +// hit this limit on writing we will send a few more packets for the +// key exchange itself. +const packetRekeyThreshold = (1 << 31) + +func (t *handshakeTransport) resetReadThresholds() { + t.readPacketsLeft = packetRekeyThreshold + if t.config.RekeyThreshold > 0 { + t.readBytesLeft = int64(t.config.RekeyThreshold) + } else if t.algorithms != nil { + t.readBytesLeft = t.algorithms.r.rekeyBytes() + } else { + t.readBytesLeft = 1 << 30 + } +} + +func (t *handshakeTransport) readOnePacket(first bool) ([]byte, error) { + p, err := t.conn.readPacket() + if err != nil { + return nil, err + } + + if t.readPacketsLeft > 0 { + t.readPacketsLeft-- + } else { + t.requestKeyExchange() + } + + if t.readBytesLeft > 0 { + t.readBytesLeft -= int64(len(p)) + } else { + t.requestKeyExchange() + } + + if debugHandshake { + t.printPacket(p, false) + } + + if first && p[0] != msgKexInit { + return nil, fmt.Errorf("ssh: first packet should be msgKexInit") + } + + if p[0] != msgKexInit { + return p, nil + } + + firstKex := t.sessionID == nil + + kex := pendingKex{ + done: make(chan error, 1), + otherInit: p, + } + t.startKex <- &kex + err = <-kex.done + + if debugHandshake { + log.Printf("%s exited key exchange (first %v), err %v", t.id(), firstKex, err) + } + + if err != nil { + return nil, err + } + + t.resetReadThresholds() + + // By default, a key exchange is hidden from higher layers by + // translating it into msgIgnore. + successPacket := []byte{msgIgnore} + if firstKex { + // sendKexInit() for the first kex waits for + // msgNewKeys so the authentication process is + // guaranteed to happen over an encrypted transport. + successPacket = []byte{msgNewKeys} + } + + return successPacket, nil +} + +const ( + kexStrictClient = "kex-strict-c-v00@openssh.com" + kexStrictServer = "kex-strict-s-v00@openssh.com" +) + +// sendKexInit sends a key change message. +func (t *handshakeTransport) sendKexInit() error { + t.mu.Lock() + defer t.mu.Unlock() + if t.sentInitMsg != nil { + // kexInits may be sent either in response to the other side, + // or because our side wants to initiate a key change, so we + // may have already sent a kexInit. In that case, don't send a + // second kexInit. + return nil + } + + msg := &kexInitMsg{ + CiphersClientServer: t.config.Ciphers, + CiphersServerClient: t.config.Ciphers, + MACsClientServer: t.config.MACs, + MACsServerClient: t.config.MACs, + CompressionClientServer: supportedCompressions, + CompressionServerClient: supportedCompressions, + } + io.ReadFull(rand.Reader, msg.Cookie[:]) + + // We mutate the KexAlgos slice, in order to add the kex-strict extension algorithm, + // and possibly to add the ext-info extension algorithm. Since the slice may be the + // user owned KeyExchanges, we create our own slice in order to avoid using user + // owned memory by mistake. + msg.KexAlgos = make([]string, 0, len(t.config.KeyExchanges)+2) // room for kex-strict and ext-info + msg.KexAlgos = append(msg.KexAlgos, t.config.KeyExchanges...) + + isServer := len(t.hostKeys) > 0 + if isServer { + for _, k := range t.hostKeys { + // If k is a MultiAlgorithmSigner, we restrict the signature + // algorithms. If k is a AlgorithmSigner, presume it supports all + // signature algorithms associated with the key format. If k is not + // an AlgorithmSigner, we can only assume it only supports the + // algorithms that matches the key format. (This means that Sign + // can't pick a different default). + keyFormat := k.PublicKey().Type() + + switch s := k.(type) { + case MultiAlgorithmSigner: + for _, algo := range algorithmsForKeyFormat(keyFormat) { + if contains(s.Algorithms(), underlyingAlgo(algo)) { + msg.ServerHostKeyAlgos = append(msg.ServerHostKeyAlgos, algo) + } + } + case AlgorithmSigner: + msg.ServerHostKeyAlgos = append(msg.ServerHostKeyAlgos, algorithmsForKeyFormat(keyFormat)...) + default: + msg.ServerHostKeyAlgos = append(msg.ServerHostKeyAlgos, keyFormat) + } + } + + if t.sessionID == nil { + msg.KexAlgos = append(msg.KexAlgos, kexStrictServer) + } + } else { + msg.ServerHostKeyAlgos = t.hostKeyAlgorithms + + // As a client we opt in to receiving SSH_MSG_EXT_INFO so we know what + // algorithms the server supports for public key authentication. See RFC + // 8308, Section 2.1. + // + // We also send the strict KEX mode extension algorithm, in order to opt + // into the strict KEX mode. + if firstKeyExchange := t.sessionID == nil; firstKeyExchange { + msg.KexAlgos = append(msg.KexAlgos, "ext-info-c") + msg.KexAlgos = append(msg.KexAlgos, kexStrictClient) + } + + } + + packet := Marshal(msg) + + // writePacket destroys the contents, so save a copy. + packetCopy := make([]byte, len(packet)) + copy(packetCopy, packet) + + if err := t.pushPacket(packetCopy); err != nil { + return err + } + + t.sentInitMsg = msg + t.sentInitPacket = packet + + return nil +} + +var errSendBannerPhase = errors.New("ssh: SendAuthBanner outside of authentication phase") + +func (t *handshakeTransport) writePacket(p []byte) error { + t.mu.Lock() + defer t.mu.Unlock() + + switch p[0] { + case msgKexInit: + return errors.New("ssh: only handshakeTransport can send kexInit") + case msgNewKeys: + return errors.New("ssh: only handshakeTransport can send newKeys") + case msgUserAuthBanner: + if t.userAuthComplete { + return errSendBannerPhase + } + case msgUserAuthSuccess: + t.userAuthComplete = true + } + + if t.writeError != nil { + return t.writeError + } + + if t.sentInitMsg != nil { + // Copy the packet so the writer can reuse the buffer. + cp := make([]byte, len(p)) + copy(cp, p) + t.pendingPackets = append(t.pendingPackets, cp) + return nil + } + + if t.writeBytesLeft > 0 { + t.writeBytesLeft -= int64(len(p)) + } else { + t.requestKeyExchange() + } + + if t.writePacketsLeft > 0 { + t.writePacketsLeft-- + } else { + t.requestKeyExchange() + } + + if err := t.pushPacket(p); err != nil { + t.writeError = err + } + + return nil +} + +func (t *handshakeTransport) Close() error { + // Close the connection. This should cause the readLoop goroutine to wake up + // and close t.startKex, which will shut down kexLoop if running. + err := t.conn.Close() + + // Wait for the kexLoop goroutine to complete. + // At that point we know that the readLoop goroutine is complete too, + // because kexLoop itself waits for readLoop to close the startKex channel. + <-t.kexLoopDone + + return err +} + +func (t *handshakeTransport) enterKeyExchange(otherInitPacket []byte) error { + if debugHandshake { + log.Printf("%s entered key exchange", t.id()) + } + + otherInit := &kexInitMsg{} + if err := Unmarshal(otherInitPacket, otherInit); err != nil { + return err + } + + magics := handshakeMagics{ + clientVersion: t.clientVersion, + serverVersion: t.serverVersion, + clientKexInit: otherInitPacket, + serverKexInit: t.sentInitPacket, + } + + clientInit := otherInit + serverInit := t.sentInitMsg + isClient := len(t.hostKeys) == 0 + if isClient { + clientInit, serverInit = serverInit, clientInit + + magics.clientKexInit = t.sentInitPacket + magics.serverKexInit = otherInitPacket + } + + var err error + t.algorithms, err = findAgreedAlgorithms(isClient, clientInit, serverInit) + if err != nil { + return err + } + + if t.sessionID == nil && ((isClient && contains(serverInit.KexAlgos, kexStrictServer)) || (!isClient && contains(clientInit.KexAlgos, kexStrictClient))) { + t.strictMode = true + if err := t.conn.setStrictMode(); err != nil { + return err + } + } + + // We don't send FirstKexFollows, but we handle receiving it. + // + // RFC 4253 section 7 defines the kex and the agreement method for + // first_kex_packet_follows. It states that the guessed packet + // should be ignored if the "kex algorithm and/or the host + // key algorithm is guessed wrong (server and client have + // different preferred algorithm), or if any of the other + // algorithms cannot be agreed upon". The other algorithms have + // already been checked above so the kex algorithm and host key + // algorithm are checked here. + if otherInit.FirstKexFollows && (clientInit.KexAlgos[0] != serverInit.KexAlgos[0] || clientInit.ServerHostKeyAlgos[0] != serverInit.ServerHostKeyAlgos[0]) { + // other side sent a kex message for the wrong algorithm, + // which we have to ignore. + if _, err := t.conn.readPacket(); err != nil { + return err + } + } + + kex, ok := kexAlgoMap[t.algorithms.kex] + if !ok { + return fmt.Errorf("ssh: unexpected key exchange algorithm %v", t.algorithms.kex) + } + + var result *kexResult + if len(t.hostKeys) > 0 { + result, err = t.server(kex, &magics) + } else { + result, err = t.client(kex, &magics) + } + + if err != nil { + return err + } + + firstKeyExchange := t.sessionID == nil + if firstKeyExchange { + t.sessionID = result.H + } + result.SessionID = t.sessionID + + if err := t.conn.prepareKeyChange(t.algorithms, result); err != nil { + return err + } + if err = t.conn.writePacket([]byte{msgNewKeys}); err != nil { + return err + } + + // On the server side, after the first SSH_MSG_NEWKEYS, send a SSH_MSG_EXT_INFO + // message with the server-sig-algs extension if the client supports it. See + // RFC 8308, Sections 2.4 and 3.1, and [PROTOCOL], Section 1.9. + if !isClient && firstKeyExchange && contains(clientInit.KexAlgos, "ext-info-c") { + supportedPubKeyAuthAlgosList := strings.Join(t.publicKeyAuthAlgorithms, ",") + extInfo := &extInfoMsg{ + NumExtensions: 2, + Payload: make([]byte, 0, 4+15+4+len(supportedPubKeyAuthAlgosList)+4+16+4+1), + } + extInfo.Payload = appendInt(extInfo.Payload, len("server-sig-algs")) + extInfo.Payload = append(extInfo.Payload, "server-sig-algs"...) + extInfo.Payload = appendInt(extInfo.Payload, len(supportedPubKeyAuthAlgosList)) + extInfo.Payload = append(extInfo.Payload, supportedPubKeyAuthAlgosList...) + extInfo.Payload = appendInt(extInfo.Payload, len("ping@openssh.com")) + extInfo.Payload = append(extInfo.Payload, "ping@openssh.com"...) + extInfo.Payload = appendInt(extInfo.Payload, 1) + extInfo.Payload = append(extInfo.Payload, "0"...) + if err := t.conn.writePacket(Marshal(extInfo)); err != nil { + return err + } + } + + if packet, err := t.conn.readPacket(); err != nil { + return err + } else if packet[0] != msgNewKeys { + return unexpectedMessageError(msgNewKeys, packet[0]) + } + + if firstKeyExchange { + // Indicates to the transport that the first key exchange is completed + // after receiving SSH_MSG_NEWKEYS. + t.conn.setInitialKEXDone() + } + + return nil +} + +// algorithmSignerWrapper is an AlgorithmSigner that only supports the default +// key format algorithm. +// +// This is technically a violation of the AlgorithmSigner interface, but it +// should be unreachable given where we use this. Anyway, at least it returns an +// error instead of panicing or producing an incorrect signature. +type algorithmSignerWrapper struct { + Signer +} + +func (a algorithmSignerWrapper) SignWithAlgorithm(rand io.Reader, data []byte, algorithm string) (*Signature, error) { + if algorithm != underlyingAlgo(a.PublicKey().Type()) { + return nil, errors.New("ssh: internal error: algorithmSignerWrapper invoked with non-default algorithm") + } + return a.Sign(rand, data) +} + +func pickHostKey(hostKeys []Signer, algo string) AlgorithmSigner { + for _, k := range hostKeys { + if s, ok := k.(MultiAlgorithmSigner); ok { + if !contains(s.Algorithms(), underlyingAlgo(algo)) { + continue + } + } + + if algo == k.PublicKey().Type() { + return algorithmSignerWrapper{k} + } + + k, ok := k.(AlgorithmSigner) + if !ok { + continue + } + for _, a := range algorithmsForKeyFormat(k.PublicKey().Type()) { + if algo == a { + return k + } + } + } + return nil +} + +func (t *handshakeTransport) server(kex kexAlgorithm, magics *handshakeMagics) (*kexResult, error) { + hostKey := pickHostKey(t.hostKeys, t.algorithms.hostKey) + if hostKey == nil { + return nil, errors.New("ssh: internal error: negotiated unsupported signature type") + } + + r, err := kex.Server(t.conn, t.config.Rand, magics, hostKey, t.algorithms.hostKey) + return r, err +} + +func (t *handshakeTransport) client(kex kexAlgorithm, magics *handshakeMagics) (*kexResult, error) { + result, err := kex.Client(t.conn, t.config.Rand, magics) + if err != nil { + return nil, err + } + + hostKey, err := ParsePublicKey(result.HostKey) + if err != nil { + return nil, err + } + + if err := verifyHostKeySignature(hostKey, t.algorithms.hostKey, result); err != nil { + return nil, err + } + + err = t.hostKeyCallback(t.dialAddress, t.remoteAddr, hostKey) + if err != nil { + return nil, err + } + + return result, nil +} diff --git a/tempfork/sshtest/ssh/handshake_test.go b/tempfork/sshtest/ssh/handshake_test.go new file mode 100644 index 000000000..2bc607b64 --- /dev/null +++ b/tempfork/sshtest/ssh/handshake_test.go @@ -0,0 +1,1021 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "bytes" + "crypto/rand" + "errors" + "fmt" + "io" + "net" + "reflect" + "runtime" + "strings" + "sync" + "testing" +) + +type testChecker struct { + calls []string +} + +func (t *testChecker) Check(dialAddr string, addr net.Addr, key PublicKey) error { + if dialAddr == "bad" { + return fmt.Errorf("dialAddr is bad") + } + + if tcpAddr, ok := addr.(*net.TCPAddr); !ok || tcpAddr == nil { + return fmt.Errorf("testChecker: got %T want *net.TCPAddr", addr) + } + + t.calls = append(t.calls, fmt.Sprintf("%s %v %s %x", dialAddr, addr, key.Type(), key.Marshal())) + + return nil +} + +// netPipe is analogous to net.Pipe, but it uses a real net.Conn, and +// therefore is buffered (net.Pipe deadlocks if both sides start with +// a write.) +func netPipe() (net.Conn, net.Conn, error) { + listener, err := net.Listen("tcp", "127.0.0.1:0") + if err != nil { + listener, err = net.Listen("tcp", "[::1]:0") + if err != nil { + return nil, nil, err + } + } + defer listener.Close() + c1, err := net.Dial("tcp", listener.Addr().String()) + if err != nil { + return nil, nil, err + } + + c2, err := listener.Accept() + if err != nil { + c1.Close() + return nil, nil, err + } + + return c1, c2, nil +} + +// noiseTransport inserts ignore messages to check that the read loop +// and the key exchange filters out these messages. +type noiseTransport struct { + keyingTransport +} + +func (t *noiseTransport) writePacket(p []byte) error { + ignore := []byte{msgIgnore} + if err := t.keyingTransport.writePacket(ignore); err != nil { + return err + } + debug := []byte{msgDebug, 1, 2, 3} + if err := t.keyingTransport.writePacket(debug); err != nil { + return err + } + + return t.keyingTransport.writePacket(p) +} + +func addNoiseTransport(t keyingTransport) keyingTransport { + return &noiseTransport{t} +} + +// handshakePair creates two handshakeTransports connected with each +// other. If the noise argument is true, both transports will try to +// confuse the other side by sending ignore and debug messages. +func handshakePair(clientConf *ClientConfig, addr string, noise bool) (client *handshakeTransport, server *handshakeTransport, err error) { + a, b, err := netPipe() + if err != nil { + return nil, nil, err + } + + var trC, trS keyingTransport + + trC = newTransport(a, rand.Reader, true) + trS = newTransport(b, rand.Reader, false) + if noise { + trC = addNoiseTransport(trC) + trS = addNoiseTransport(trS) + } + clientConf.SetDefaults() + + v := []byte("version") + client = newClientTransport(trC, v, v, clientConf, addr, a.RemoteAddr()) + + serverConf := &ServerConfig{} + serverConf.AddHostKey(testSigners["ecdsa"]) + serverConf.AddHostKey(testSigners["rsa"]) + serverConf.SetDefaults() + server = newServerTransport(trS, v, v, serverConf) + + if err := server.waitSession(); err != nil { + return nil, nil, fmt.Errorf("server.waitSession: %v", err) + } + if err := client.waitSession(); err != nil { + return nil, nil, fmt.Errorf("client.waitSession: %v", err) + } + + return client, server, nil +} + +func TestHandshakeBasic(t *testing.T) { + if runtime.GOOS == "plan9" { + t.Skip("see golang.org/issue/7237") + } + + checker := &syncChecker{ + waitCall: make(chan int, 10), + called: make(chan int, 10), + } + + checker.waitCall <- 1 + trC, trS, err := handshakePair(&ClientConfig{HostKeyCallback: checker.Check}, "addr", false) + if err != nil { + t.Fatalf("handshakePair: %v", err) + } + + defer trC.Close() + defer trS.Close() + + // Let first kex complete normally. + <-checker.called + + clientDone := make(chan int, 0) + gotHalf := make(chan int, 0) + const N = 20 + errorCh := make(chan error, 1) + + go func() { + defer close(clientDone) + // Client writes a bunch of stuff, and does a key + // change in the middle. This should not confuse the + // handshake in progress. We do this twice, so we test + // that the packet buffer is reset correctly. + for i := 0; i < N; i++ { + p := []byte{msgRequestSuccess, byte(i)} + if err := trC.writePacket(p); err != nil { + errorCh <- err + trC.Close() + return + } + if (i % 10) == 5 { + <-gotHalf + // halfway through, we request a key change. + trC.requestKeyExchange() + + // Wait until we can be sure the key + // change has really started before we + // write more. + <-checker.called + } + if (i % 10) == 7 { + // write some packets until the kex + // completes, to test buffering of + // packets. + checker.waitCall <- 1 + } + } + errorCh <- nil + }() + + // Server checks that client messages come in cleanly + i := 0 + for ; i < N; i++ { + p, err := trS.readPacket() + if err != nil && err != io.EOF { + t.Fatalf("server error: %v", err) + } + if (i % 10) == 5 { + gotHalf <- 1 + } + + want := []byte{msgRequestSuccess, byte(i)} + if bytes.Compare(p, want) != 0 { + t.Errorf("message %d: got %v, want %v", i, p, want) + } + } + <-clientDone + if err := <-errorCh; err != nil { + t.Fatalf("sendPacket: %v", err) + } + if i != N { + t.Errorf("received %d messages, want 10.", i) + } + + close(checker.called) + if _, ok := <-checker.called; ok { + // If all went well, we registered exactly 2 key changes: one + // that establishes the session, and one that we requested + // additionally. + t.Fatalf("got another host key checks after 2 handshakes") + } +} + +func TestForceFirstKex(t *testing.T) { + // like handshakePair, but must access the keyingTransport. + checker := &testChecker{} + clientConf := &ClientConfig{HostKeyCallback: checker.Check} + a, b, err := netPipe() + if err != nil { + t.Fatalf("netPipe: %v", err) + } + + var trC, trS keyingTransport + + trC = newTransport(a, rand.Reader, true) + + // This is the disallowed packet: + trC.writePacket(Marshal(&serviceRequestMsg{serviceUserAuth})) + + // Rest of the setup. + trS = newTransport(b, rand.Reader, false) + clientConf.SetDefaults() + + v := []byte("version") + client := newClientTransport(trC, v, v, clientConf, "addr", a.RemoteAddr()) + + serverConf := &ServerConfig{} + serverConf.AddHostKey(testSigners["ecdsa"]) + serverConf.AddHostKey(testSigners["rsa"]) + serverConf.SetDefaults() + server := newServerTransport(trS, v, v, serverConf) + + defer client.Close() + defer server.Close() + + // We setup the initial key exchange, but the remote side + // tries to send serviceRequestMsg in cleartext, which is + // disallowed. + + if err := server.waitSession(); err == nil { + t.Errorf("server first kex init should reject unexpected packet") + } +} + +func TestHandshakeAutoRekeyWrite(t *testing.T) { + checker := &syncChecker{ + called: make(chan int, 10), + waitCall: nil, + } + clientConf := &ClientConfig{HostKeyCallback: checker.Check} + clientConf.RekeyThreshold = 500 + trC, trS, err := handshakePair(clientConf, "addr", false) + if err != nil { + t.Fatalf("handshakePair: %v", err) + } + defer trC.Close() + defer trS.Close() + + input := make([]byte, 251) + input[0] = msgRequestSuccess + + done := make(chan int, 1) + const numPacket = 5 + go func() { + defer close(done) + j := 0 + for ; j < numPacket; j++ { + if p, err := trS.readPacket(); err != nil { + break + } else if !bytes.Equal(input, p) { + t.Errorf("got packet type %d, want %d", p[0], input[0]) + } + } + + if j != numPacket { + t.Errorf("got %d, want 5 messages", j) + } + }() + + <-checker.called + + for i := 0; i < numPacket; i++ { + p := make([]byte, len(input)) + copy(p, input) + if err := trC.writePacket(p); err != nil { + t.Errorf("writePacket: %v", err) + } + if i == 2 { + // Make sure the kex is in progress. + <-checker.called + } + + } + <-done +} + +type syncChecker struct { + waitCall chan int + called chan int +} + +func (c *syncChecker) Check(dialAddr string, addr net.Addr, key PublicKey) error { + c.called <- 1 + if c.waitCall != nil { + <-c.waitCall + } + return nil +} + +func TestHandshakeAutoRekeyRead(t *testing.T) { + sync := &syncChecker{ + called: make(chan int, 2), + waitCall: nil, + } + clientConf := &ClientConfig{ + HostKeyCallback: sync.Check, + } + clientConf.RekeyThreshold = 500 + + trC, trS, err := handshakePair(clientConf, "addr", false) + if err != nil { + t.Fatalf("handshakePair: %v", err) + } + defer trC.Close() + defer trS.Close() + + packet := make([]byte, 501) + packet[0] = msgRequestSuccess + if err := trS.writePacket(packet); err != nil { + t.Fatalf("writePacket: %v", err) + } + + // While we read out the packet, a key change will be + // initiated. + errorCh := make(chan error, 1) + go func() { + _, err := trC.readPacket() + errorCh <- err + }() + + if err := <-errorCh; err != nil { + t.Fatalf("readPacket(client): %v", err) + } + + <-sync.called +} + +// errorKeyingTransport generates errors after a given number of +// read/write operations. +type errorKeyingTransport struct { + packetConn + readLeft, writeLeft int +} + +func (n *errorKeyingTransport) prepareKeyChange(*algorithms, *kexResult) error { + return nil +} + +func (n *errorKeyingTransport) getSessionID() []byte { + return nil +} + +func (n *errorKeyingTransport) writePacket(packet []byte) error { + if n.writeLeft == 0 { + n.Close() + return errors.New("barf") + } + + n.writeLeft-- + return n.packetConn.writePacket(packet) +} + +func (n *errorKeyingTransport) readPacket() ([]byte, error) { + if n.readLeft == 0 { + n.Close() + return nil, errors.New("barf") + } + + n.readLeft-- + return n.packetConn.readPacket() +} + +func (n *errorKeyingTransport) setStrictMode() error { return nil } + +func (n *errorKeyingTransport) setInitialKEXDone() {} + +func TestHandshakeErrorHandlingRead(t *testing.T) { + for i := 0; i < 20; i++ { + testHandshakeErrorHandlingN(t, i, -1, false) + } +} + +func TestHandshakeErrorHandlingWrite(t *testing.T) { + for i := 0; i < 20; i++ { + testHandshakeErrorHandlingN(t, -1, i, false) + } +} + +func TestHandshakeErrorHandlingReadCoupled(t *testing.T) { + for i := 0; i < 20; i++ { + testHandshakeErrorHandlingN(t, i, -1, true) + } +} + +func TestHandshakeErrorHandlingWriteCoupled(t *testing.T) { + for i := 0; i < 20; i++ { + testHandshakeErrorHandlingN(t, -1, i, true) + } +} + +// testHandshakeErrorHandlingN runs handshakes, injecting errors. If +// handshakeTransport deadlocks, the go runtime will detect it and +// panic. +func testHandshakeErrorHandlingN(t *testing.T, readLimit, writeLimit int, coupled bool) { + if (runtime.GOOS == "js" || runtime.GOOS == "wasip1") && runtime.GOARCH == "wasm" { + t.Skipf("skipping on %s/wasm; see golang.org/issue/32840", runtime.GOOS) + } + msg := Marshal(&serviceRequestMsg{strings.Repeat("x", int(minRekeyThreshold)/4)}) + + a, b := memPipe() + defer a.Close() + defer b.Close() + + key := testSigners["ecdsa"] + serverConf := Config{RekeyThreshold: minRekeyThreshold} + serverConf.SetDefaults() + serverConn := newHandshakeTransport(&errorKeyingTransport{a, readLimit, writeLimit}, &serverConf, []byte{'a'}, []byte{'b'}) + serverConn.hostKeys = []Signer{key} + go serverConn.readLoop() + go serverConn.kexLoop() + + clientConf := Config{RekeyThreshold: 10 * minRekeyThreshold} + clientConf.SetDefaults() + clientConn := newHandshakeTransport(&errorKeyingTransport{b, -1, -1}, &clientConf, []byte{'a'}, []byte{'b'}) + clientConn.hostKeyAlgorithms = []string{key.PublicKey().Type()} + clientConn.hostKeyCallback = InsecureIgnoreHostKey() + go clientConn.readLoop() + go clientConn.kexLoop() + + var wg sync.WaitGroup + + for _, hs := range []packetConn{serverConn, clientConn} { + if !coupled { + wg.Add(2) + go func(c packetConn) { + for i := 0; ; i++ { + str := fmt.Sprintf("%08x", i) + strings.Repeat("x", int(minRekeyThreshold)/4-8) + err := c.writePacket(Marshal(&serviceRequestMsg{str})) + if err != nil { + break + } + } + wg.Done() + c.Close() + }(hs) + go func(c packetConn) { + for { + _, err := c.readPacket() + if err != nil { + break + } + } + wg.Done() + }(hs) + } else { + wg.Add(1) + go func(c packetConn) { + for { + _, err := c.readPacket() + if err != nil { + break + } + if err := c.writePacket(msg); err != nil { + break + } + + } + wg.Done() + }(hs) + } + } + wg.Wait() +} + +func TestDisconnect(t *testing.T) { + if runtime.GOOS == "plan9" { + t.Skip("see golang.org/issue/7237") + } + checker := &testChecker{} + trC, trS, err := handshakePair(&ClientConfig{HostKeyCallback: checker.Check}, "addr", false) + if err != nil { + t.Fatalf("handshakePair: %v", err) + } + + defer trC.Close() + defer trS.Close() + + trC.writePacket([]byte{msgRequestSuccess, 0, 0}) + errMsg := &disconnectMsg{ + Reason: 42, + Message: "such is life", + } + trC.writePacket(Marshal(errMsg)) + trC.writePacket([]byte{msgRequestSuccess, 0, 0}) + + packet, err := trS.readPacket() + if err != nil { + t.Fatalf("readPacket 1: %v", err) + } + if packet[0] != msgRequestSuccess { + t.Errorf("got packet %v, want packet type %d", packet, msgRequestSuccess) + } + + _, err = trS.readPacket() + if err == nil { + t.Errorf("readPacket 2 succeeded") + } else if !reflect.DeepEqual(err, errMsg) { + t.Errorf("got error %#v, want %#v", err, errMsg) + } + + _, err = trS.readPacket() + if err == nil { + t.Errorf("readPacket 3 succeeded") + } +} + +func TestHandshakeRekeyDefault(t *testing.T) { + clientConf := &ClientConfig{ + Config: Config{ + Ciphers: []string{"aes128-ctr"}, + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + trC, trS, err := handshakePair(clientConf, "addr", false) + if err != nil { + t.Fatalf("handshakePair: %v", err) + } + defer trC.Close() + defer trS.Close() + + trC.writePacket([]byte{msgRequestSuccess, 0, 0}) + trC.Close() + + rgb := (1024 + trC.readBytesLeft) >> 30 + wgb := (1024 + trC.writeBytesLeft) >> 30 + + if rgb != 64 { + t.Errorf("got rekey after %dG read, want 64G", rgb) + } + if wgb != 64 { + t.Errorf("got rekey after %dG write, want 64G", wgb) + } +} + +func TestHandshakeAEADCipherNoMAC(t *testing.T) { + for _, cipher := range []string{chacha20Poly1305ID, gcm128CipherID} { + checker := &syncChecker{ + called: make(chan int, 1), + } + clientConf := &ClientConfig{ + Config: Config{ + Ciphers: []string{cipher}, + MACs: []string{}, + }, + HostKeyCallback: checker.Check, + } + trC, trS, err := handshakePair(clientConf, "addr", false) + if err != nil { + t.Fatalf("handshakePair: %v", err) + } + defer trC.Close() + defer trS.Close() + + <-checker.called + } +} + +// TestNoSHA2Support tests a host key Signer that is not an AlgorithmSigner and +// therefore can't do SHA-2 signatures. Ensures the server does not advertise +// support for them in this case. +func TestNoSHA2Support(t *testing.T) { + c1, c2, err := netPipe() + if err != nil { + t.Fatalf("netPipe: %v", err) + } + defer c1.Close() + defer c2.Close() + + serverConf := &ServerConfig{ + PasswordCallback: func(conn ConnMetadata, password []byte) (*Permissions, error) { + return &Permissions{}, nil + }, + } + serverConf.AddHostKey(&legacyRSASigner{testSigners["rsa"]}) + go func() { + _, _, _, err := NewServerConn(c1, serverConf) + if err != nil { + t.Error(err) + } + }() + + clientConf := &ClientConfig{ + User: "test", + Auth: []AuthMethod{Password("testpw")}, + HostKeyCallback: FixedHostKey(testSigners["rsa"].PublicKey()), + } + + if _, _, _, err := NewClientConn(c2, "", clientConf); err != nil { + t.Fatal(err) + } +} + +func TestMultiAlgoSignerHandshake(t *testing.T) { + algorithmSigner, ok := testSigners["rsa"].(AlgorithmSigner) + if !ok { + t.Fatal("rsa test signer does not implement the AlgorithmSigner interface") + } + multiAlgoSigner, err := NewSignerWithAlgorithms(algorithmSigner, []string{KeyAlgoRSASHA256, KeyAlgoRSASHA512}) + if err != nil { + t.Fatalf("unable to create multi algorithm signer: %v", err) + } + c1, c2, err := netPipe() + if err != nil { + t.Fatalf("netPipe: %v", err) + } + defer c1.Close() + defer c2.Close() + + serverConf := &ServerConfig{ + PasswordCallback: func(conn ConnMetadata, password []byte) (*Permissions, error) { + return &Permissions{}, nil + }, + } + serverConf.AddHostKey(multiAlgoSigner) + go NewServerConn(c1, serverConf) + + clientConf := &ClientConfig{ + User: "test", + Auth: []AuthMethod{Password("testpw")}, + HostKeyCallback: FixedHostKey(testSigners["rsa"].PublicKey()), + HostKeyAlgorithms: []string{KeyAlgoRSASHA512}, + } + + if _, _, _, err := NewClientConn(c2, "", clientConf); err != nil { + t.Fatal(err) + } +} + +func TestMultiAlgoSignerNoCommonHostKeyAlgo(t *testing.T) { + algorithmSigner, ok := testSigners["rsa"].(AlgorithmSigner) + if !ok { + t.Fatal("rsa test signer does not implement the AlgorithmSigner interface") + } + multiAlgoSigner, err := NewSignerWithAlgorithms(algorithmSigner, []string{KeyAlgoRSASHA256, KeyAlgoRSASHA512}) + if err != nil { + t.Fatalf("unable to create multi algorithm signer: %v", err) + } + c1, c2, err := netPipe() + if err != nil { + t.Fatalf("netPipe: %v", err) + } + defer c1.Close() + defer c2.Close() + + // ssh-rsa is disabled server side + serverConf := &ServerConfig{ + PasswordCallback: func(conn ConnMetadata, password []byte) (*Permissions, error) { + return &Permissions{}, nil + }, + } + serverConf.AddHostKey(multiAlgoSigner) + go NewServerConn(c1, serverConf) + + // the client only supports ssh-rsa + clientConf := &ClientConfig{ + User: "test", + Auth: []AuthMethod{Password("testpw")}, + HostKeyCallback: FixedHostKey(testSigners["rsa"].PublicKey()), + HostKeyAlgorithms: []string{KeyAlgoRSA}, + } + + _, _, _, err = NewClientConn(c2, "", clientConf) + if err == nil { + t.Fatal("succeeded connecting with no common hostkey algorithm") + } +} + +func TestPickIncompatibleHostKeyAlgo(t *testing.T) { + algorithmSigner, ok := testSigners["rsa"].(AlgorithmSigner) + if !ok { + t.Fatal("rsa test signer does not implement the AlgorithmSigner interface") + } + multiAlgoSigner, err := NewSignerWithAlgorithms(algorithmSigner, []string{KeyAlgoRSASHA256, KeyAlgoRSASHA512}) + if err != nil { + t.Fatalf("unable to create multi algorithm signer: %v", err) + } + signer := pickHostKey([]Signer{multiAlgoSigner}, KeyAlgoRSA) + if signer != nil { + t.Fatal("incompatible signer returned") + } +} + +func TestStrictKEXResetSeqFirstKEX(t *testing.T) { + if runtime.GOOS == "plan9" { + t.Skip("see golang.org/issue/7237") + } + + checker := &syncChecker{ + waitCall: make(chan int, 10), + called: make(chan int, 10), + } + + checker.waitCall <- 1 + trC, trS, err := handshakePair(&ClientConfig{HostKeyCallback: checker.Check}, "addr", false) + if err != nil { + t.Fatalf("handshakePair: %v", err) + } + <-checker.called + + t.Cleanup(func() { + trC.Close() + trS.Close() + }) + + // Throw away the msgExtInfo packet sent during the handshake by the server + _, err = trC.readPacket() + if err != nil { + t.Fatalf("readPacket failed: %s", err) + } + + // close the handshake transports before checking the sequence number to + // avoid races. + trC.Close() + trS.Close() + + // check that the sequence number counters. We reset after msgNewKeys, but + // then the server immediately writes msgExtInfo, and we close the + // transports so we expect read 2, write 0 on the client and read 1, write 1 + // on the server. + if trC.conn.(*transport).reader.seqNum != 2 || trC.conn.(*transport).writer.seqNum != 0 || + trS.conn.(*transport).reader.seqNum != 1 || trS.conn.(*transport).writer.seqNum != 1 { + t.Errorf( + "unexpected sequence counters:\nclient: reader %d (expected 2), writer %d (expected 0)\nserver: reader %d (expected 1), writer %d (expected 1)", + trC.conn.(*transport).reader.seqNum, + trC.conn.(*transport).writer.seqNum, + trS.conn.(*transport).reader.seqNum, + trS.conn.(*transport).writer.seqNum, + ) + } +} + +func TestStrictKEXResetSeqSuccessiveKEX(t *testing.T) { + if runtime.GOOS == "plan9" { + t.Skip("see golang.org/issue/7237") + } + + checker := &syncChecker{ + waitCall: make(chan int, 10), + called: make(chan int, 10), + } + + checker.waitCall <- 1 + trC, trS, err := handshakePair(&ClientConfig{HostKeyCallback: checker.Check}, "addr", false) + if err != nil { + t.Fatalf("handshakePair: %v", err) + } + <-checker.called + + t.Cleanup(func() { + trC.Close() + trS.Close() + }) + + // Throw away the msgExtInfo packet sent during the handshake by the server + _, err = trC.readPacket() + if err != nil { + t.Fatalf("readPacket failed: %s", err) + } + + // write and read five packets on either side to bump the sequence numbers + for i := 0; i < 5; i++ { + if err := trC.writePacket([]byte{msgRequestSuccess}); err != nil { + t.Fatalf("writePacket failed: %s", err) + } + if _, err := trS.readPacket(); err != nil { + t.Fatalf("readPacket failed: %s", err) + } + if err := trS.writePacket([]byte{msgRequestSuccess}); err != nil { + t.Fatalf("writePacket failed: %s", err) + } + if _, err := trC.readPacket(); err != nil { + t.Fatalf("readPacket failed: %s", err) + } + } + + // Request a key exchange, which should cause the sequence numbers to reset + checker.waitCall <- 1 + trC.requestKeyExchange() + <-checker.called + + // write a packet on the client, and then read it, to verify the key change has actually happened, since + // the HostKeyCallback is called _during_ the handshake, so isn't actually indicative of the handshake + // finishing. + dummyPacket := []byte{99} + if err := trS.writePacket(dummyPacket); err != nil { + t.Fatalf("writePacket failed: %s", err) + } + if p, err := trC.readPacket(); err != nil { + t.Fatalf("readPacket failed: %s", err) + } else if !bytes.Equal(p, dummyPacket) { + t.Fatalf("unexpected packet: got %x, want %x", p, dummyPacket) + } + + // close the handshake transports before checking the sequence number to + // avoid races. + trC.Close() + trS.Close() + + if trC.conn.(*transport).reader.seqNum != 2 || trC.conn.(*transport).writer.seqNum != 0 || + trS.conn.(*transport).reader.seqNum != 1 || trS.conn.(*transport).writer.seqNum != 1 { + t.Errorf( + "unexpected sequence counters:\nclient: reader %d (expected 2), writer %d (expected 0)\nserver: reader %d (expected 1), writer %d (expected 1)", + trC.conn.(*transport).reader.seqNum, + trC.conn.(*transport).writer.seqNum, + trS.conn.(*transport).reader.seqNum, + trS.conn.(*transport).writer.seqNum, + ) + } +} + +func TestSeqNumIncrease(t *testing.T) { + if runtime.GOOS == "plan9" { + t.Skip("see golang.org/issue/7237") + } + + checker := &syncChecker{ + waitCall: make(chan int, 10), + called: make(chan int, 10), + } + + checker.waitCall <- 1 + trC, trS, err := handshakePair(&ClientConfig{HostKeyCallback: checker.Check}, "addr", false) + if err != nil { + t.Fatalf("handshakePair: %v", err) + } + <-checker.called + + t.Cleanup(func() { + trC.Close() + trS.Close() + }) + + // Throw away the msgExtInfo packet sent during the handshake by the server + _, err = trC.readPacket() + if err != nil { + t.Fatalf("readPacket failed: %s", err) + } + + // write and read five packets on either side to bump the sequence numbers + for i := 0; i < 5; i++ { + if err := trC.writePacket([]byte{msgRequestSuccess}); err != nil { + t.Fatalf("writePacket failed: %s", err) + } + if _, err := trS.readPacket(); err != nil { + t.Fatalf("readPacket failed: %s", err) + } + if err := trS.writePacket([]byte{msgRequestSuccess}); err != nil { + t.Fatalf("writePacket failed: %s", err) + } + if _, err := trC.readPacket(); err != nil { + t.Fatalf("readPacket failed: %s", err) + } + } + + // close the handshake transports before checking the sequence number to + // avoid races. + trC.Close() + trS.Close() + + if trC.conn.(*transport).reader.seqNum != 7 || trC.conn.(*transport).writer.seqNum != 5 || + trS.conn.(*transport).reader.seqNum != 6 || trS.conn.(*transport).writer.seqNum != 6 { + t.Errorf( + "unexpected sequence counters:\nclient: reader %d (expected 7), writer %d (expected 5)\nserver: reader %d (expected 6), writer %d (expected 6)", + trC.conn.(*transport).reader.seqNum, + trC.conn.(*transport).writer.seqNum, + trS.conn.(*transport).reader.seqNum, + trS.conn.(*transport).writer.seqNum, + ) + } +} + +func TestStrictKEXUnexpectedMsg(t *testing.T) { + if runtime.GOOS == "plan9" { + t.Skip("see golang.org/issue/7237") + } + + // Check that unexpected messages during the handshake cause failure + _, _, err := handshakePair(&ClientConfig{HostKeyCallback: func(hostname string, remote net.Addr, key PublicKey) error { return nil }}, "addr", true) + if err == nil { + t.Fatal("handshake should fail when there are unexpected messages during the handshake") + } + + trC, trS, err := handshakePair(&ClientConfig{HostKeyCallback: func(hostname string, remote net.Addr, key PublicKey) error { return nil }}, "addr", false) + if err != nil { + t.Fatalf("handshake failed: %s", err) + } + + // Check that ignore/debug pacekts are still ignored outside of the handshake + if err := trC.writePacket([]byte{msgIgnore}); err != nil { + t.Fatalf("writePacket failed: %s", err) + } + if err := trC.writePacket([]byte{msgDebug}); err != nil { + t.Fatalf("writePacket failed: %s", err) + } + dummyPacket := []byte{99} + if err := trC.writePacket(dummyPacket); err != nil { + t.Fatalf("writePacket failed: %s", err) + } + + if p, err := trS.readPacket(); err != nil { + t.Fatalf("readPacket failed: %s", err) + } else if !bytes.Equal(p, dummyPacket) { + t.Fatalf("unexpected packet: got %x, want %x", p, dummyPacket) + } +} + +func TestStrictKEXMixed(t *testing.T) { + // Test that we still support a mixed connection, where one side sends kex-strict but the other + // side doesn't. + + a, b, err := netPipe() + if err != nil { + t.Fatalf("netPipe failed: %s", err) + } + + var trC, trS keyingTransport + + trC = newTransport(a, rand.Reader, true) + trS = newTransport(b, rand.Reader, false) + trS = addNoiseTransport(trS) + + clientConf := &ClientConfig{HostKeyCallback: func(hostname string, remote net.Addr, key PublicKey) error { return nil }} + clientConf.SetDefaults() + + v := []byte("version") + client := newClientTransport(trC, v, v, clientConf, "addr", a.RemoteAddr()) + + serverConf := &ServerConfig{} + serverConf.AddHostKey(testSigners["ecdsa"]) + serverConf.AddHostKey(testSigners["rsa"]) + serverConf.SetDefaults() + + transport := newHandshakeTransport(trS, &serverConf.Config, []byte("version"), []byte("version")) + transport.hostKeys = serverConf.hostKeys + transport.publicKeyAuthAlgorithms = serverConf.PublicKeyAuthAlgorithms + + readOneFailure := make(chan error, 1) + go func() { + if _, err := transport.readOnePacket(true); err != nil { + readOneFailure <- err + } + }() + + // Basically sendKexInit, but without the kex-strict extension algorithm + msg := &kexInitMsg{ + KexAlgos: transport.config.KeyExchanges, + CiphersClientServer: transport.config.Ciphers, + CiphersServerClient: transport.config.Ciphers, + MACsClientServer: transport.config.MACs, + MACsServerClient: transport.config.MACs, + CompressionClientServer: supportedCompressions, + CompressionServerClient: supportedCompressions, + ServerHostKeyAlgos: []string{KeyAlgoRSASHA256, KeyAlgoRSASHA512, KeyAlgoRSA}, + } + packet := Marshal(msg) + // writePacket destroys the contents, so save a copy. + packetCopy := make([]byte, len(packet)) + copy(packetCopy, packet) + if err := transport.pushPacket(packetCopy); err != nil { + t.Fatalf("pushPacket: %s", err) + } + transport.sentInitMsg = msg + transport.sentInitPacket = packet + + if err := transport.getWriteError(); err != nil { + t.Fatalf("getWriteError failed: %s", err) + } + var request *pendingKex + select { + case err = <-readOneFailure: + t.Fatalf("server readOnePacket failed: %s", err) + case request = <-transport.startKex: + break + } + + // We expect the following calls to fail if the side which does not support + // kex-strict sends unexpected/ignored packets during the handshake, even if + // the other side does support kex-strict. + + if err := transport.enterKeyExchange(request.otherInit); err != nil { + t.Fatalf("enterKeyExchange failed: %s", err) + } + if err := client.waitSession(); err != nil { + t.Fatalf("client.waitSession: %v", err) + } +} diff --git a/tempfork/sshtest/ssh/kex.go b/tempfork/sshtest/ssh/kex.go new file mode 100644 index 000000000..8a05f7990 --- /dev/null +++ b/tempfork/sshtest/ssh/kex.go @@ -0,0 +1,786 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "crypto" + "crypto/ecdsa" + "crypto/elliptic" + "crypto/rand" + "crypto/subtle" + "encoding/binary" + "errors" + "fmt" + "io" + "math/big" + + "golang.org/x/crypto/curve25519" +) + +const ( + kexAlgoDH1SHA1 = "diffie-hellman-group1-sha1" + kexAlgoDH14SHA1 = "diffie-hellman-group14-sha1" + kexAlgoDH14SHA256 = "diffie-hellman-group14-sha256" + kexAlgoDH16SHA512 = "diffie-hellman-group16-sha512" + kexAlgoECDH256 = "ecdh-sha2-nistp256" + kexAlgoECDH384 = "ecdh-sha2-nistp384" + kexAlgoECDH521 = "ecdh-sha2-nistp521" + kexAlgoCurve25519SHA256LibSSH = "curve25519-sha256@libssh.org" + kexAlgoCurve25519SHA256 = "curve25519-sha256" + + // For the following kex only the client half contains a production + // ready implementation. The server half only consists of a minimal + // implementation to satisfy the automated tests. + kexAlgoDHGEXSHA1 = "diffie-hellman-group-exchange-sha1" + kexAlgoDHGEXSHA256 = "diffie-hellman-group-exchange-sha256" +) + +// kexResult captures the outcome of a key exchange. +type kexResult struct { + // Session hash. See also RFC 4253, section 8. + H []byte + + // Shared secret. See also RFC 4253, section 8. + K []byte + + // Host key as hashed into H. + HostKey []byte + + // Signature of H. + Signature []byte + + // A cryptographic hash function that matches the security + // level of the key exchange algorithm. It is used for + // calculating H, and for deriving keys from H and K. + Hash crypto.Hash + + // The session ID, which is the first H computed. This is used + // to derive key material inside the transport. + SessionID []byte +} + +// handshakeMagics contains data that is always included in the +// session hash. +type handshakeMagics struct { + clientVersion, serverVersion []byte + clientKexInit, serverKexInit []byte +} + +func (m *handshakeMagics) write(w io.Writer) { + writeString(w, m.clientVersion) + writeString(w, m.serverVersion) + writeString(w, m.clientKexInit) + writeString(w, m.serverKexInit) +} + +// kexAlgorithm abstracts different key exchange algorithms. +type kexAlgorithm interface { + // Server runs server-side key agreement, signing the result + // with a hostkey. algo is the negotiated algorithm, and may + // be a certificate type. + Server(p packetConn, rand io.Reader, magics *handshakeMagics, s AlgorithmSigner, algo string) (*kexResult, error) + + // Client runs the client-side key agreement. Caller is + // responsible for verifying the host key signature. + Client(p packetConn, rand io.Reader, magics *handshakeMagics) (*kexResult, error) +} + +// dhGroup is a multiplicative group suitable for implementing Diffie-Hellman key agreement. +type dhGroup struct { + g, p, pMinus1 *big.Int + hashFunc crypto.Hash +} + +func (group *dhGroup) diffieHellman(theirPublic, myPrivate *big.Int) (*big.Int, error) { + if theirPublic.Cmp(bigOne) <= 0 || theirPublic.Cmp(group.pMinus1) >= 0 { + return nil, errors.New("ssh: DH parameter out of bounds") + } + return new(big.Int).Exp(theirPublic, myPrivate, group.p), nil +} + +func (group *dhGroup) Client(c packetConn, randSource io.Reader, magics *handshakeMagics) (*kexResult, error) { + var x *big.Int + for { + var err error + if x, err = rand.Int(randSource, group.pMinus1); err != nil { + return nil, err + } + if x.Sign() > 0 { + break + } + } + + X := new(big.Int).Exp(group.g, x, group.p) + kexDHInit := kexDHInitMsg{ + X: X, + } + if err := c.writePacket(Marshal(&kexDHInit)); err != nil { + return nil, err + } + + packet, err := c.readPacket() + if err != nil { + return nil, err + } + + var kexDHReply kexDHReplyMsg + if err = Unmarshal(packet, &kexDHReply); err != nil { + return nil, err + } + + ki, err := group.diffieHellman(kexDHReply.Y, x) + if err != nil { + return nil, err + } + + h := group.hashFunc.New() + magics.write(h) + writeString(h, kexDHReply.HostKey) + writeInt(h, X) + writeInt(h, kexDHReply.Y) + K := make([]byte, intLength(ki)) + marshalInt(K, ki) + h.Write(K) + + return &kexResult{ + H: h.Sum(nil), + K: K, + HostKey: kexDHReply.HostKey, + Signature: kexDHReply.Signature, + Hash: group.hashFunc, + }, nil +} + +func (group *dhGroup) Server(c packetConn, randSource io.Reader, magics *handshakeMagics, priv AlgorithmSigner, algo string) (result *kexResult, err error) { + packet, err := c.readPacket() + if err != nil { + return + } + var kexDHInit kexDHInitMsg + if err = Unmarshal(packet, &kexDHInit); err != nil { + return + } + + var y *big.Int + for { + if y, err = rand.Int(randSource, group.pMinus1); err != nil { + return + } + if y.Sign() > 0 { + break + } + } + + Y := new(big.Int).Exp(group.g, y, group.p) + ki, err := group.diffieHellman(kexDHInit.X, y) + if err != nil { + return nil, err + } + + hostKeyBytes := priv.PublicKey().Marshal() + + h := group.hashFunc.New() + magics.write(h) + writeString(h, hostKeyBytes) + writeInt(h, kexDHInit.X) + writeInt(h, Y) + + K := make([]byte, intLength(ki)) + marshalInt(K, ki) + h.Write(K) + + H := h.Sum(nil) + + // H is already a hash, but the hostkey signing will apply its + // own key-specific hash algorithm. + sig, err := signAndMarshal(priv, randSource, H, algo) + if err != nil { + return nil, err + } + + kexDHReply := kexDHReplyMsg{ + HostKey: hostKeyBytes, + Y: Y, + Signature: sig, + } + packet = Marshal(&kexDHReply) + + err = c.writePacket(packet) + return &kexResult{ + H: H, + K: K, + HostKey: hostKeyBytes, + Signature: sig, + Hash: group.hashFunc, + }, err +} + +// ecdh performs Elliptic Curve Diffie-Hellman key exchange as +// described in RFC 5656, section 4. +type ecdh struct { + curve elliptic.Curve +} + +func (kex *ecdh) Client(c packetConn, rand io.Reader, magics *handshakeMagics) (*kexResult, error) { + ephKey, err := ecdsa.GenerateKey(kex.curve, rand) + if err != nil { + return nil, err + } + + kexInit := kexECDHInitMsg{ + ClientPubKey: elliptic.Marshal(kex.curve, ephKey.PublicKey.X, ephKey.PublicKey.Y), + } + + serialized := Marshal(&kexInit) + if err := c.writePacket(serialized); err != nil { + return nil, err + } + + packet, err := c.readPacket() + if err != nil { + return nil, err + } + + var reply kexECDHReplyMsg + if err = Unmarshal(packet, &reply); err != nil { + return nil, err + } + + x, y, err := unmarshalECKey(kex.curve, reply.EphemeralPubKey) + if err != nil { + return nil, err + } + + // generate shared secret + secret, _ := kex.curve.ScalarMult(x, y, ephKey.D.Bytes()) + + h := ecHash(kex.curve).New() + magics.write(h) + writeString(h, reply.HostKey) + writeString(h, kexInit.ClientPubKey) + writeString(h, reply.EphemeralPubKey) + K := make([]byte, intLength(secret)) + marshalInt(K, secret) + h.Write(K) + + return &kexResult{ + H: h.Sum(nil), + K: K, + HostKey: reply.HostKey, + Signature: reply.Signature, + Hash: ecHash(kex.curve), + }, nil +} + +// unmarshalECKey parses and checks an EC key. +func unmarshalECKey(curve elliptic.Curve, pubkey []byte) (x, y *big.Int, err error) { + x, y = elliptic.Unmarshal(curve, pubkey) + if x == nil { + return nil, nil, errors.New("ssh: elliptic.Unmarshal failure") + } + if !validateECPublicKey(curve, x, y) { + return nil, nil, errors.New("ssh: public key not on curve") + } + return x, y, nil +} + +// validateECPublicKey checks that the point is a valid public key for +// the given curve. See [SEC1], 3.2.2 +func validateECPublicKey(curve elliptic.Curve, x, y *big.Int) bool { + if x.Sign() == 0 && y.Sign() == 0 { + return false + } + + if x.Cmp(curve.Params().P) >= 0 { + return false + } + + if y.Cmp(curve.Params().P) >= 0 { + return false + } + + if !curve.IsOnCurve(x, y) { + return false + } + + // We don't check if N * PubKey == 0, since + // + // - the NIST curves have cofactor = 1, so this is implicit. + // (We don't foresee an implementation that supports non NIST + // curves) + // + // - for ephemeral keys, we don't need to worry about small + // subgroup attacks. + return true +} + +func (kex *ecdh) Server(c packetConn, rand io.Reader, magics *handshakeMagics, priv AlgorithmSigner, algo string) (result *kexResult, err error) { + packet, err := c.readPacket() + if err != nil { + return nil, err + } + + var kexECDHInit kexECDHInitMsg + if err = Unmarshal(packet, &kexECDHInit); err != nil { + return nil, err + } + + clientX, clientY, err := unmarshalECKey(kex.curve, kexECDHInit.ClientPubKey) + if err != nil { + return nil, err + } + + // We could cache this key across multiple users/multiple + // connection attempts, but the benefit is small. OpenSSH + // generates a new key for each incoming connection. + ephKey, err := ecdsa.GenerateKey(kex.curve, rand) + if err != nil { + return nil, err + } + + hostKeyBytes := priv.PublicKey().Marshal() + + serializedEphKey := elliptic.Marshal(kex.curve, ephKey.PublicKey.X, ephKey.PublicKey.Y) + + // generate shared secret + secret, _ := kex.curve.ScalarMult(clientX, clientY, ephKey.D.Bytes()) + + h := ecHash(kex.curve).New() + magics.write(h) + writeString(h, hostKeyBytes) + writeString(h, kexECDHInit.ClientPubKey) + writeString(h, serializedEphKey) + + K := make([]byte, intLength(secret)) + marshalInt(K, secret) + h.Write(K) + + H := h.Sum(nil) + + // H is already a hash, but the hostkey signing will apply its + // own key-specific hash algorithm. + sig, err := signAndMarshal(priv, rand, H, algo) + if err != nil { + return nil, err + } + + reply := kexECDHReplyMsg{ + EphemeralPubKey: serializedEphKey, + HostKey: hostKeyBytes, + Signature: sig, + } + + serialized := Marshal(&reply) + if err := c.writePacket(serialized); err != nil { + return nil, err + } + + return &kexResult{ + H: H, + K: K, + HostKey: reply.HostKey, + Signature: sig, + Hash: ecHash(kex.curve), + }, nil +} + +// ecHash returns the hash to match the given elliptic curve, see RFC +// 5656, section 6.2.1 +func ecHash(curve elliptic.Curve) crypto.Hash { + bitSize := curve.Params().BitSize + switch { + case bitSize <= 256: + return crypto.SHA256 + case bitSize <= 384: + return crypto.SHA384 + } + return crypto.SHA512 +} + +var kexAlgoMap = map[string]kexAlgorithm{} + +func init() { + // This is the group called diffie-hellman-group1-sha1 in + // RFC 4253 and Oakley Group 2 in RFC 2409. + p, _ := new(big.Int).SetString("FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE649286651ECE65381FFFFFFFFFFFFFFFF", 16) + kexAlgoMap[kexAlgoDH1SHA1] = &dhGroup{ + g: new(big.Int).SetInt64(2), + p: p, + pMinus1: new(big.Int).Sub(p, bigOne), + hashFunc: crypto.SHA1, + } + + // This are the groups called diffie-hellman-group14-sha1 and + // diffie-hellman-group14-sha256 in RFC 4253 and RFC 8268, + // and Oakley Group 14 in RFC 3526. + p, _ = new(big.Int).SetString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group14 := &dhGroup{ + g: new(big.Int).SetInt64(2), + p: p, + pMinus1: new(big.Int).Sub(p, bigOne), + } + + kexAlgoMap[kexAlgoDH14SHA1] = &dhGroup{ + g: group14.g, p: group14.p, pMinus1: group14.pMinus1, + hashFunc: crypto.SHA1, + } + kexAlgoMap[kexAlgoDH14SHA256] = &dhGroup{ + g: group14.g, p: group14.p, pMinus1: group14.pMinus1, + hashFunc: crypto.SHA256, + } + + // This is the group called diffie-hellman-group16-sha512 in RFC + // 8268 and Oakley Group 16 in RFC 3526. + p, _ = new(big.Int).SetString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kexAlgoMap[kexAlgoDH16SHA512] = &dhGroup{ + g: new(big.Int).SetInt64(2), + p: p, + pMinus1: new(big.Int).Sub(p, bigOne), + hashFunc: crypto.SHA512, + } + + kexAlgoMap[kexAlgoECDH521] = &ecdh{elliptic.P521()} + kexAlgoMap[kexAlgoECDH384] = &ecdh{elliptic.P384()} + kexAlgoMap[kexAlgoECDH256] = &ecdh{elliptic.P256()} + kexAlgoMap[kexAlgoCurve25519SHA256] = &curve25519sha256{} + kexAlgoMap[kexAlgoCurve25519SHA256LibSSH] = &curve25519sha256{} + kexAlgoMap[kexAlgoDHGEXSHA1] = &dhGEXSHA{hashFunc: crypto.SHA1} + kexAlgoMap[kexAlgoDHGEXSHA256] = &dhGEXSHA{hashFunc: crypto.SHA256} +} + +// curve25519sha256 implements the curve25519-sha256 (formerly known as +// curve25519-sha256@libssh.org) key exchange method, as described in RFC 8731. +type curve25519sha256 struct{} + +type curve25519KeyPair struct { + priv [32]byte + pub [32]byte +} + +func (kp *curve25519KeyPair) generate(rand io.Reader) error { + if _, err := io.ReadFull(rand, kp.priv[:]); err != nil { + return err + } + curve25519.ScalarBaseMult(&kp.pub, &kp.priv) + return nil +} + +// curve25519Zeros is just an array of 32 zero bytes so that we have something +// convenient to compare against in order to reject curve25519 points with the +// wrong order. +var curve25519Zeros [32]byte + +func (kex *curve25519sha256) Client(c packetConn, rand io.Reader, magics *handshakeMagics) (*kexResult, error) { + var kp curve25519KeyPair + if err := kp.generate(rand); err != nil { + return nil, err + } + if err := c.writePacket(Marshal(&kexECDHInitMsg{kp.pub[:]})); err != nil { + return nil, err + } + + packet, err := c.readPacket() + if err != nil { + return nil, err + } + + var reply kexECDHReplyMsg + if err = Unmarshal(packet, &reply); err != nil { + return nil, err + } + if len(reply.EphemeralPubKey) != 32 { + return nil, errors.New("ssh: peer's curve25519 public value has wrong length") + } + + var servPub, secret [32]byte + copy(servPub[:], reply.EphemeralPubKey) + curve25519.ScalarMult(&secret, &kp.priv, &servPub) + if subtle.ConstantTimeCompare(secret[:], curve25519Zeros[:]) == 1 { + return nil, errors.New("ssh: peer's curve25519 public value has wrong order") + } + + h := crypto.SHA256.New() + magics.write(h) + writeString(h, reply.HostKey) + writeString(h, kp.pub[:]) + writeString(h, reply.EphemeralPubKey) + + ki := new(big.Int).SetBytes(secret[:]) + K := make([]byte, intLength(ki)) + marshalInt(K, ki) + h.Write(K) + + return &kexResult{ + H: h.Sum(nil), + K: K, + HostKey: reply.HostKey, + Signature: reply.Signature, + Hash: crypto.SHA256, + }, nil +} + +func (kex *curve25519sha256) Server(c packetConn, rand io.Reader, magics *handshakeMagics, priv AlgorithmSigner, algo string) (result *kexResult, err error) { + packet, err := c.readPacket() + if err != nil { + return + } + var kexInit kexECDHInitMsg + if err = Unmarshal(packet, &kexInit); err != nil { + return + } + + if len(kexInit.ClientPubKey) != 32 { + return nil, errors.New("ssh: peer's curve25519 public value has wrong length") + } + + var kp curve25519KeyPair + if err := kp.generate(rand); err != nil { + return nil, err + } + + var clientPub, secret [32]byte + copy(clientPub[:], kexInit.ClientPubKey) + curve25519.ScalarMult(&secret, &kp.priv, &clientPub) + if subtle.ConstantTimeCompare(secret[:], curve25519Zeros[:]) == 1 { + return nil, errors.New("ssh: peer's curve25519 public value has wrong order") + } + + hostKeyBytes := priv.PublicKey().Marshal() + + h := crypto.SHA256.New() + magics.write(h) + writeString(h, hostKeyBytes) + writeString(h, kexInit.ClientPubKey) + writeString(h, kp.pub[:]) + + ki := new(big.Int).SetBytes(secret[:]) + K := make([]byte, intLength(ki)) + marshalInt(K, ki) + h.Write(K) + + H := h.Sum(nil) + + sig, err := signAndMarshal(priv, rand, H, algo) + if err != nil { + return nil, err + } + + reply := kexECDHReplyMsg{ + EphemeralPubKey: kp.pub[:], + HostKey: hostKeyBytes, + Signature: sig, + } + if err := c.writePacket(Marshal(&reply)); err != nil { + return nil, err + } + return &kexResult{ + H: H, + K: K, + HostKey: hostKeyBytes, + Signature: sig, + Hash: crypto.SHA256, + }, nil +} + +// dhGEXSHA implements the diffie-hellman-group-exchange-sha1 and +// diffie-hellman-group-exchange-sha256 key agreement protocols, +// as described in RFC 4419 +type dhGEXSHA struct { + hashFunc crypto.Hash +} + +const ( + dhGroupExchangeMinimumBits = 2048 + dhGroupExchangePreferredBits = 2048 + dhGroupExchangeMaximumBits = 8192 +) + +func (gex *dhGEXSHA) Client(c packetConn, randSource io.Reader, magics *handshakeMagics) (*kexResult, error) { + // Send GexRequest + kexDHGexRequest := kexDHGexRequestMsg{ + MinBits: dhGroupExchangeMinimumBits, + PreferedBits: dhGroupExchangePreferredBits, + MaxBits: dhGroupExchangeMaximumBits, + } + if err := c.writePacket(Marshal(&kexDHGexRequest)); err != nil { + return nil, err + } + + // Receive GexGroup + packet, err := c.readPacket() + if err != nil { + return nil, err + } + + var msg kexDHGexGroupMsg + if err = Unmarshal(packet, &msg); err != nil { + return nil, err + } + + // reject if p's bit length < dhGroupExchangeMinimumBits or > dhGroupExchangeMaximumBits + if msg.P.BitLen() < dhGroupExchangeMinimumBits || msg.P.BitLen() > dhGroupExchangeMaximumBits { + return nil, fmt.Errorf("ssh: server-generated gex p is out of range (%d bits)", msg.P.BitLen()) + } + + // Check if g is safe by verifying that 1 < g < p-1 + pMinusOne := new(big.Int).Sub(msg.P, bigOne) + if msg.G.Cmp(bigOne) <= 0 || msg.G.Cmp(pMinusOne) >= 0 { + return nil, fmt.Errorf("ssh: server provided gex g is not safe") + } + + // Send GexInit + pHalf := new(big.Int).Rsh(msg.P, 1) + x, err := rand.Int(randSource, pHalf) + if err != nil { + return nil, err + } + X := new(big.Int).Exp(msg.G, x, msg.P) + kexDHGexInit := kexDHGexInitMsg{ + X: X, + } + if err := c.writePacket(Marshal(&kexDHGexInit)); err != nil { + return nil, err + } + + // Receive GexReply + packet, err = c.readPacket() + if err != nil { + return nil, err + } + + var kexDHGexReply kexDHGexReplyMsg + if err = Unmarshal(packet, &kexDHGexReply); err != nil { + return nil, err + } + + if kexDHGexReply.Y.Cmp(bigOne) <= 0 || kexDHGexReply.Y.Cmp(pMinusOne) >= 0 { + return nil, errors.New("ssh: DH parameter out of bounds") + } + kInt := new(big.Int).Exp(kexDHGexReply.Y, x, msg.P) + + // Check if k is safe by verifying that k > 1 and k < p - 1 + if kInt.Cmp(bigOne) <= 0 || kInt.Cmp(pMinusOne) >= 0 { + return nil, fmt.Errorf("ssh: derived k is not safe") + } + + h := gex.hashFunc.New() + magics.write(h) + writeString(h, kexDHGexReply.HostKey) + binary.Write(h, binary.BigEndian, uint32(dhGroupExchangeMinimumBits)) + binary.Write(h, binary.BigEndian, uint32(dhGroupExchangePreferredBits)) + binary.Write(h, binary.BigEndian, uint32(dhGroupExchangeMaximumBits)) + writeInt(h, msg.P) + writeInt(h, msg.G) + writeInt(h, X) + writeInt(h, kexDHGexReply.Y) + K := make([]byte, intLength(kInt)) + marshalInt(K, kInt) + h.Write(K) + + return &kexResult{ + H: h.Sum(nil), + K: K, + HostKey: kexDHGexReply.HostKey, + Signature: kexDHGexReply.Signature, + Hash: gex.hashFunc, + }, nil +} + +// Server half implementation of the Diffie Hellman Key Exchange with SHA1 and SHA256. +// +// This is a minimal implementation to satisfy the automated tests. +func (gex dhGEXSHA) Server(c packetConn, randSource io.Reader, magics *handshakeMagics, priv AlgorithmSigner, algo string) (result *kexResult, err error) { + // Receive GexRequest + packet, err := c.readPacket() + if err != nil { + return + } + var kexDHGexRequest kexDHGexRequestMsg + if err = Unmarshal(packet, &kexDHGexRequest); err != nil { + return + } + + // Send GexGroup + // This is the group called diffie-hellman-group14-sha1 in RFC + // 4253 and Oakley Group 14 in RFC 3526. + p, _ := new(big.Int).SetString("FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3DC2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F83655D23DCA3AD961C62F356208552BB9ED529077096966D670C354E4ABC9804F1746C08CA18217C32905E462E36CE3BE39E772C180E86039B2783A2EC07A28FB5C55DF06F4C52C9DE2BCBF6955817183995497CEA956AE515D2261898FA051015728E5A8AACAA68FFFFFFFFFFFFFFFF", 16) + g := big.NewInt(2) + + msg := &kexDHGexGroupMsg{ + P: p, + G: g, + } + if err := c.writePacket(Marshal(msg)); err != nil { + return nil, err + } + + // Receive GexInit + packet, err = c.readPacket() + if err != nil { + return + } + var kexDHGexInit kexDHGexInitMsg + if err = Unmarshal(packet, &kexDHGexInit); err != nil { + return + } + + pHalf := new(big.Int).Rsh(p, 1) + + y, err := rand.Int(randSource, pHalf) + if err != nil { + return + } + Y := new(big.Int).Exp(g, y, p) + + pMinusOne := new(big.Int).Sub(p, bigOne) + if kexDHGexInit.X.Cmp(bigOne) <= 0 || kexDHGexInit.X.Cmp(pMinusOne) >= 0 { + return nil, errors.New("ssh: DH parameter out of bounds") + } + kInt := new(big.Int).Exp(kexDHGexInit.X, y, p) + + hostKeyBytes := priv.PublicKey().Marshal() + + h := gex.hashFunc.New() + magics.write(h) + writeString(h, hostKeyBytes) + binary.Write(h, binary.BigEndian, uint32(dhGroupExchangeMinimumBits)) + binary.Write(h, binary.BigEndian, uint32(dhGroupExchangePreferredBits)) + binary.Write(h, binary.BigEndian, uint32(dhGroupExchangeMaximumBits)) + writeInt(h, p) + writeInt(h, g) + writeInt(h, kexDHGexInit.X) + writeInt(h, Y) + + K := make([]byte, intLength(kInt)) + marshalInt(K, kInt) + h.Write(K) + + H := h.Sum(nil) + + // H is already a hash, but the hostkey signing will apply its + // own key-specific hash algorithm. + sig, err := signAndMarshal(priv, randSource, H, algo) + if err != nil { + return nil, err + } + + kexDHGexReply := kexDHGexReplyMsg{ + HostKey: hostKeyBytes, + Y: Y, + Signature: sig, + } + packet = Marshal(&kexDHGexReply) + + err = c.writePacket(packet) + + return &kexResult{ + H: H, + K: K, + HostKey: hostKeyBytes, + Signature: sig, + Hash: gex.hashFunc, + }, err +} diff --git a/tempfork/sshtest/ssh/kex_test.go b/tempfork/sshtest/ssh/kex_test.go new file mode 100644 index 000000000..cb7f66a50 --- /dev/null +++ b/tempfork/sshtest/ssh/kex_test.go @@ -0,0 +1,106 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +// Key exchange tests. + +import ( + "crypto/rand" + "fmt" + "reflect" + "sync" + "testing" +) + +// Runs multiple key exchanges concurrent to detect potential data races with +// kex obtained from the global kexAlgoMap. +// This test needs to be executed using the race detector in order to detect +// race conditions. +func TestKexes(t *testing.T) { + type kexResultErr struct { + result *kexResult + err error + } + + for name, kex := range kexAlgoMap { + t.Run(name, func(t *testing.T) { + wg := sync.WaitGroup{} + for i := 0; i < 3; i++ { + wg.Add(1) + go func() { + defer wg.Done() + a, b := memPipe() + + s := make(chan kexResultErr, 1) + c := make(chan kexResultErr, 1) + var magics handshakeMagics + go func() { + r, e := kex.Client(a, rand.Reader, &magics) + a.Close() + c <- kexResultErr{r, e} + }() + go func() { + r, e := kex.Server(b, rand.Reader, &magics, testSigners["ecdsa"].(AlgorithmSigner), testSigners["ecdsa"].PublicKey().Type()) + b.Close() + s <- kexResultErr{r, e} + }() + + clientRes := <-c + serverRes := <-s + if clientRes.err != nil { + t.Errorf("client: %v", clientRes.err) + } + if serverRes.err != nil { + t.Errorf("server: %v", serverRes.err) + } + if !reflect.DeepEqual(clientRes.result, serverRes.result) { + t.Errorf("kex %q: mismatch %#v, %#v", name, clientRes.result, serverRes.result) + } + }() + } + wg.Wait() + }) + } +} + +func BenchmarkKexes(b *testing.B) { + type kexResultErr struct { + result *kexResult + err error + } + + for name, kex := range kexAlgoMap { + b.Run(name, func(b *testing.B) { + for i := 0; i < b.N; i++ { + t1, t2 := memPipe() + + s := make(chan kexResultErr, 1) + c := make(chan kexResultErr, 1) + var magics handshakeMagics + + go func() { + r, e := kex.Client(t1, rand.Reader, &magics) + t1.Close() + c <- kexResultErr{r, e} + }() + go func() { + r, e := kex.Server(t2, rand.Reader, &magics, testSigners["ecdsa"].(AlgorithmSigner), testSigners["ecdsa"].PublicKey().Type()) + t2.Close() + s <- kexResultErr{r, e} + }() + + clientRes := <-c + serverRes := <-s + + if clientRes.err != nil { + panic(fmt.Sprintf("client: %v", clientRes.err)) + } + if serverRes.err != nil { + panic(fmt.Sprintf("server: %v", serverRes.err)) + } + } + }) + } +} diff --git a/tempfork/sshtest/ssh/keys.go b/tempfork/sshtest/ssh/keys.go new file mode 100644 index 000000000..4a3d769d9 --- /dev/null +++ b/tempfork/sshtest/ssh/keys.go @@ -0,0 +1,1626 @@ +// Copyright 2012 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "bytes" + "crypto" + "crypto/dsa" + "crypto/ecdsa" + "crypto/ed25519" + "crypto/elliptic" + "crypto/md5" + "crypto/rand" + "crypto/rsa" + "crypto/sha256" + "crypto/x509" + "encoding/asn1" + "encoding/base64" + "encoding/binary" + "encoding/hex" + "encoding/pem" + "errors" + "fmt" + "io" + "math/big" + "strings" +) + +// Public key algorithms names. These values can appear in PublicKey.Type, +// ClientConfig.HostKeyAlgorithms, Signature.Format, or as AlgorithmSigner +// arguments. +const ( + KeyAlgoRSA = "ssh-rsa" + KeyAlgoDSA = "ssh-dss" + KeyAlgoECDSA256 = "ecdsa-sha2-nistp256" + KeyAlgoSKECDSA256 = "sk-ecdsa-sha2-nistp256@openssh.com" + KeyAlgoECDSA384 = "ecdsa-sha2-nistp384" + KeyAlgoECDSA521 = "ecdsa-sha2-nistp521" + KeyAlgoED25519 = "ssh-ed25519" + KeyAlgoSKED25519 = "sk-ssh-ed25519@openssh.com" + + // KeyAlgoRSASHA256 and KeyAlgoRSASHA512 are only public key algorithms, not + // public key formats, so they can't appear as a PublicKey.Type. The + // corresponding PublicKey.Type is KeyAlgoRSA. See RFC 8332, Section 2. + KeyAlgoRSASHA256 = "rsa-sha2-256" + KeyAlgoRSASHA512 = "rsa-sha2-512" +) + +const ( + // Deprecated: use KeyAlgoRSA. + SigAlgoRSA = KeyAlgoRSA + // Deprecated: use KeyAlgoRSASHA256. + SigAlgoRSASHA2256 = KeyAlgoRSASHA256 + // Deprecated: use KeyAlgoRSASHA512. + SigAlgoRSASHA2512 = KeyAlgoRSASHA512 +) + +// parsePubKey parses a public key of the given algorithm. +// Use ParsePublicKey for keys with prepended algorithm. +func parsePubKey(in []byte, algo string) (pubKey PublicKey, rest []byte, err error) { + switch algo { + case KeyAlgoRSA: + return parseRSA(in) + case KeyAlgoDSA: + return parseDSA(in) + case KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521: + return parseECDSA(in) + case KeyAlgoSKECDSA256: + return parseSKECDSA(in) + case KeyAlgoED25519: + return parseED25519(in) + case KeyAlgoSKED25519: + return parseSKEd25519(in) + case CertAlgoRSAv01, CertAlgoDSAv01, CertAlgoECDSA256v01, CertAlgoECDSA384v01, CertAlgoECDSA521v01, CertAlgoSKECDSA256v01, CertAlgoED25519v01, CertAlgoSKED25519v01: + cert, err := parseCert(in, certKeyAlgoNames[algo]) + if err != nil { + return nil, nil, err + } + return cert, nil, nil + } + return nil, nil, fmt.Errorf("ssh: unknown key algorithm: %v", algo) +} + +// parseAuthorizedKey parses a public key in OpenSSH authorized_keys format +// (see sshd(8) manual page) once the options and key type fields have been +// removed. +func parseAuthorizedKey(in []byte) (out PublicKey, comment string, err error) { + in = bytes.TrimSpace(in) + + i := bytes.IndexAny(in, " \t") + if i == -1 { + i = len(in) + } + base64Key := in[:i] + + key := make([]byte, base64.StdEncoding.DecodedLen(len(base64Key))) + n, err := base64.StdEncoding.Decode(key, base64Key) + if err != nil { + return nil, "", err + } + key = key[:n] + out, err = ParsePublicKey(key) + if err != nil { + return nil, "", err + } + comment = string(bytes.TrimSpace(in[i:])) + return out, comment, nil +} + +// ParseKnownHosts parses an entry in the format of the known_hosts file. +// +// The known_hosts format is documented in the sshd(8) manual page. This +// function will parse a single entry from in. On successful return, marker +// will contain the optional marker value (i.e. "cert-authority" or "revoked") +// or else be empty, hosts will contain the hosts that this entry matches, +// pubKey will contain the public key and comment will contain any trailing +// comment at the end of the line. See the sshd(8) manual page for the various +// forms that a host string can take. +// +// The unparsed remainder of the input will be returned in rest. This function +// can be called repeatedly to parse multiple entries. +// +// If no entries were found in the input then err will be io.EOF. Otherwise a +// non-nil err value indicates a parse error. +func ParseKnownHosts(in []byte) (marker string, hosts []string, pubKey PublicKey, comment string, rest []byte, err error) { + for len(in) > 0 { + end := bytes.IndexByte(in, '\n') + if end != -1 { + rest = in[end+1:] + in = in[:end] + } else { + rest = nil + } + + end = bytes.IndexByte(in, '\r') + if end != -1 { + in = in[:end] + } + + in = bytes.TrimSpace(in) + if len(in) == 0 || in[0] == '#' { + in = rest + continue + } + + i := bytes.IndexAny(in, " \t") + if i == -1 { + in = rest + continue + } + + // Strip out the beginning of the known_host key. + // This is either an optional marker or a (set of) hostname(s). + keyFields := bytes.Fields(in) + if len(keyFields) < 3 || len(keyFields) > 5 { + return "", nil, nil, "", nil, errors.New("ssh: invalid entry in known_hosts data") + } + + // keyFields[0] is either "@cert-authority", "@revoked" or a comma separated + // list of hosts + marker := "" + if keyFields[0][0] == '@' { + marker = string(keyFields[0][1:]) + keyFields = keyFields[1:] + } + + hosts := string(keyFields[0]) + // keyFields[1] contains the key type (e.g. “ssh-rsa”). + // However, that information is duplicated inside the + // base64-encoded key and so is ignored here. + + key := bytes.Join(keyFields[2:], []byte(" ")) + if pubKey, comment, err = parseAuthorizedKey(key); err != nil { + return "", nil, nil, "", nil, err + } + + return marker, strings.Split(hosts, ","), pubKey, comment, rest, nil + } + + return "", nil, nil, "", nil, io.EOF +} + +// ParseAuthorizedKey parses a public key from an authorized_keys +// file used in OpenSSH according to the sshd(8) manual page. +func ParseAuthorizedKey(in []byte) (out PublicKey, comment string, options []string, rest []byte, err error) { + for len(in) > 0 { + end := bytes.IndexByte(in, '\n') + if end != -1 { + rest = in[end+1:] + in = in[:end] + } else { + rest = nil + } + + end = bytes.IndexByte(in, '\r') + if end != -1 { + in = in[:end] + } + + in = bytes.TrimSpace(in) + if len(in) == 0 || in[0] == '#' { + in = rest + continue + } + + i := bytes.IndexAny(in, " \t") + if i == -1 { + in = rest + continue + } + + if out, comment, err = parseAuthorizedKey(in[i:]); err == nil { + return out, comment, options, rest, nil + } + + // No key type recognised. Maybe there's an options field at + // the beginning. + var b byte + inQuote := false + var candidateOptions []string + optionStart := 0 + for i, b = range in { + isEnd := !inQuote && (b == ' ' || b == '\t') + if (b == ',' && !inQuote) || isEnd { + if i-optionStart > 0 { + candidateOptions = append(candidateOptions, string(in[optionStart:i])) + } + optionStart = i + 1 + } + if isEnd { + break + } + if b == '"' && (i == 0 || (i > 0 && in[i-1] != '\\')) { + inQuote = !inQuote + } + } + for i < len(in) && (in[i] == ' ' || in[i] == '\t') { + i++ + } + if i == len(in) { + // Invalid line: unmatched quote + in = rest + continue + } + + in = in[i:] + i = bytes.IndexAny(in, " \t") + if i == -1 { + in = rest + continue + } + + if out, comment, err = parseAuthorizedKey(in[i:]); err == nil { + options = candidateOptions + return out, comment, options, rest, nil + } + + in = rest + continue + } + + return nil, "", nil, nil, errors.New("ssh: no key found") +} + +// ParsePublicKey parses an SSH public key formatted for use in +// the SSH wire protocol according to RFC 4253, section 6.6. +func ParsePublicKey(in []byte) (out PublicKey, err error) { + algo, in, ok := parseString(in) + if !ok { + return nil, errShortRead + } + var rest []byte + out, rest, err = parsePubKey(in, string(algo)) + if len(rest) > 0 { + return nil, errors.New("ssh: trailing junk in public key") + } + + return out, err +} + +// MarshalAuthorizedKey serializes key for inclusion in an OpenSSH +// authorized_keys file. The return value ends with newline. +func MarshalAuthorizedKey(key PublicKey) []byte { + b := &bytes.Buffer{} + b.WriteString(key.Type()) + b.WriteByte(' ') + e := base64.NewEncoder(base64.StdEncoding, b) + e.Write(key.Marshal()) + e.Close() + b.WriteByte('\n') + return b.Bytes() +} + +// MarshalPrivateKey returns a PEM block with the private key serialized in the +// OpenSSH format. +func MarshalPrivateKey(key crypto.PrivateKey, comment string) (*pem.Block, error) { + return marshalOpenSSHPrivateKey(key, comment, unencryptedOpenSSHMarshaler) +} + +// PublicKey represents a public key using an unspecified algorithm. +// +// Some PublicKeys provided by this package also implement CryptoPublicKey. +type PublicKey interface { + // Type returns the key format name, e.g. "ssh-rsa". + Type() string + + // Marshal returns the serialized key data in SSH wire format, with the name + // prefix. To unmarshal the returned data, use the ParsePublicKey function. + Marshal() []byte + + // Verify that sig is a signature on the given data using this key. This + // method will hash the data appropriately first. sig.Format is allowed to + // be any signature algorithm compatible with the key type, the caller + // should check if it has more stringent requirements. + Verify(data []byte, sig *Signature) error +} + +// CryptoPublicKey, if implemented by a PublicKey, +// returns the underlying crypto.PublicKey form of the key. +type CryptoPublicKey interface { + CryptoPublicKey() crypto.PublicKey +} + +// A Signer can create signatures that verify against a public key. +// +// Some Signers provided by this package also implement MultiAlgorithmSigner. +type Signer interface { + // PublicKey returns the associated PublicKey. + PublicKey() PublicKey + + // Sign returns a signature for the given data. This method will hash the + // data appropriately first. The signature algorithm is expected to match + // the key format returned by the PublicKey.Type method (and not to be any + // alternative algorithm supported by the key format). + Sign(rand io.Reader, data []byte) (*Signature, error) +} + +// An AlgorithmSigner is a Signer that also supports specifying an algorithm to +// use for signing. +// +// An AlgorithmSigner can't advertise the algorithms it supports, unless it also +// implements MultiAlgorithmSigner, so it should be prepared to be invoked with +// every algorithm supported by the public key format. +type AlgorithmSigner interface { + Signer + + // SignWithAlgorithm is like Signer.Sign, but allows specifying a desired + // signing algorithm. Callers may pass an empty string for the algorithm in + // which case the AlgorithmSigner will use a default algorithm. This default + // doesn't currently control any behavior in this package. + SignWithAlgorithm(rand io.Reader, data []byte, algorithm string) (*Signature, error) +} + +// MultiAlgorithmSigner is an AlgorithmSigner that also reports the algorithms +// supported by that signer. +type MultiAlgorithmSigner interface { + AlgorithmSigner + + // Algorithms returns the available algorithms in preference order. The list + // must not be empty, and it must not include certificate types. + Algorithms() []string +} + +// NewSignerWithAlgorithms returns a signer restricted to the specified +// algorithms. The algorithms must be set in preference order. The list must not +// be empty, and it must not include certificate types. An error is returned if +// the specified algorithms are incompatible with the public key type. +func NewSignerWithAlgorithms(signer AlgorithmSigner, algorithms []string) (MultiAlgorithmSigner, error) { + if len(algorithms) == 0 { + return nil, errors.New("ssh: please specify at least one valid signing algorithm") + } + var signerAlgos []string + supportedAlgos := algorithmsForKeyFormat(underlyingAlgo(signer.PublicKey().Type())) + if s, ok := signer.(*multiAlgorithmSigner); ok { + signerAlgos = s.Algorithms() + } else { + signerAlgos = supportedAlgos + } + + for _, algo := range algorithms { + if !contains(supportedAlgos, algo) { + return nil, fmt.Errorf("ssh: algorithm %q is not supported for key type %q", + algo, signer.PublicKey().Type()) + } + if !contains(signerAlgos, algo) { + return nil, fmt.Errorf("ssh: algorithm %q is restricted for the provided signer", algo) + } + } + return &multiAlgorithmSigner{ + AlgorithmSigner: signer, + supportedAlgorithms: algorithms, + }, nil +} + +type multiAlgorithmSigner struct { + AlgorithmSigner + supportedAlgorithms []string +} + +func (s *multiAlgorithmSigner) Algorithms() []string { + return s.supportedAlgorithms +} + +func (s *multiAlgorithmSigner) isAlgorithmSupported(algorithm string) bool { + if algorithm == "" { + algorithm = underlyingAlgo(s.PublicKey().Type()) + } + for _, algo := range s.supportedAlgorithms { + if algorithm == algo { + return true + } + } + return false +} + +func (s *multiAlgorithmSigner) SignWithAlgorithm(rand io.Reader, data []byte, algorithm string) (*Signature, error) { + if !s.isAlgorithmSupported(algorithm) { + return nil, fmt.Errorf("ssh: algorithm %q is not supported: %v", algorithm, s.supportedAlgorithms) + } + return s.AlgorithmSigner.SignWithAlgorithm(rand, data, algorithm) +} + +type rsaPublicKey rsa.PublicKey + +func (r *rsaPublicKey) Type() string { + return "ssh-rsa" +} + +// parseRSA parses an RSA key according to RFC 4253, section 6.6. +func parseRSA(in []byte) (out PublicKey, rest []byte, err error) { + var w struct { + E *big.Int + N *big.Int + Rest []byte `ssh:"rest"` + } + if err := Unmarshal(in, &w); err != nil { + return nil, nil, err + } + + if w.E.BitLen() > 24 { + return nil, nil, errors.New("ssh: exponent too large") + } + e := w.E.Int64() + if e < 3 || e&1 == 0 { + return nil, nil, errors.New("ssh: incorrect exponent") + } + + var key rsa.PublicKey + key.E = int(e) + key.N = w.N + return (*rsaPublicKey)(&key), w.Rest, nil +} + +func (r *rsaPublicKey) Marshal() []byte { + e := new(big.Int).SetInt64(int64(r.E)) + // RSA publickey struct layout should match the struct used by + // parseRSACert in the x/crypto/ssh/agent package. + wirekey := struct { + Name string + E *big.Int + N *big.Int + }{ + KeyAlgoRSA, + e, + r.N, + } + return Marshal(&wirekey) +} + +func (r *rsaPublicKey) Verify(data []byte, sig *Signature) error { + supportedAlgos := algorithmsForKeyFormat(r.Type()) + if !contains(supportedAlgos, sig.Format) { + return fmt.Errorf("ssh: signature type %s for key type %s", sig.Format, r.Type()) + } + hash := hashFuncs[sig.Format] + h := hash.New() + h.Write(data) + digest := h.Sum(nil) + + // Signatures in PKCS1v15 must match the key's modulus in + // length. However with SSH, some signers provide RSA + // signatures which are missing the MSB 0's of the bignum + // represented. With ssh-rsa signatures, this is encouraged by + // the spec (even though e.g. OpenSSH will give the full + // length unconditionally). With rsa-sha2-* signatures, the + // verifier is allowed to support these, even though they are + // out of spec. See RFC 4253 Section 6.6 for ssh-rsa and RFC + // 8332 Section 3 for rsa-sha2-* details. + // + // In practice: + // * OpenSSH always allows "short" signatures: + // https://github.com/openssh/openssh-portable/blob/V_9_8_P1/ssh-rsa.c#L526 + // but always generates padded signatures: + // https://github.com/openssh/openssh-portable/blob/V_9_8_P1/ssh-rsa.c#L439 + // + // * PuTTY versions 0.81 and earlier will generate short + // signatures for all RSA signature variants. Note that + // PuTTY is embedded in other software, such as WinSCP and + // FileZilla. At the time of writing, a patch has been + // applied to PuTTY to generate padded signatures for + // rsa-sha2-*, but not yet released: + // https://git.tartarus.org/?p=simon/putty.git;a=commitdiff;h=a5bcf3d384e1bf15a51a6923c3724cbbee022d8e + // + // * SSH.NET versions 2024.0.0 and earlier will generate short + // signatures for all RSA signature variants, fixed in 2024.1.0: + // https://github.com/sshnet/SSH.NET/releases/tag/2024.1.0 + // + // As a result, we pad these up to the key size by inserting + // leading 0's. + // + // Note that support for short signatures with rsa-sha2-* may + // be removed in the future due to such signatures not being + // allowed by the spec. + blob := sig.Blob + keySize := (*rsa.PublicKey)(r).Size() + if len(blob) < keySize { + padded := make([]byte, keySize) + copy(padded[keySize-len(blob):], blob) + blob = padded + } + return rsa.VerifyPKCS1v15((*rsa.PublicKey)(r), hash, digest, blob) +} + +func (r *rsaPublicKey) CryptoPublicKey() crypto.PublicKey { + return (*rsa.PublicKey)(r) +} + +type dsaPublicKey dsa.PublicKey + +func (k *dsaPublicKey) Type() string { + return "ssh-dss" +} + +func checkDSAParams(param *dsa.Parameters) error { + // SSH specifies FIPS 186-2, which only provided a single size + // (1024 bits) DSA key. FIPS 186-3 allows for larger key + // sizes, which would confuse SSH. + if l := param.P.BitLen(); l != 1024 { + return fmt.Errorf("ssh: unsupported DSA key size %d", l) + } + + return nil +} + +// parseDSA parses an DSA key according to RFC 4253, section 6.6. +func parseDSA(in []byte) (out PublicKey, rest []byte, err error) { + var w struct { + P, Q, G, Y *big.Int + Rest []byte `ssh:"rest"` + } + if err := Unmarshal(in, &w); err != nil { + return nil, nil, err + } + + param := dsa.Parameters{ + P: w.P, + Q: w.Q, + G: w.G, + } + if err := checkDSAParams(¶m); err != nil { + return nil, nil, err + } + + key := &dsaPublicKey{ + Parameters: param, + Y: w.Y, + } + return key, w.Rest, nil +} + +func (k *dsaPublicKey) Marshal() []byte { + // DSA publickey struct layout should match the struct used by + // parseDSACert in the x/crypto/ssh/agent package. + w := struct { + Name string + P, Q, G, Y *big.Int + }{ + k.Type(), + k.P, + k.Q, + k.G, + k.Y, + } + + return Marshal(&w) +} + +func (k *dsaPublicKey) Verify(data []byte, sig *Signature) error { + if sig.Format != k.Type() { + return fmt.Errorf("ssh: signature type %s for key type %s", sig.Format, k.Type()) + } + h := hashFuncs[sig.Format].New() + h.Write(data) + digest := h.Sum(nil) + + // Per RFC 4253, section 6.6, + // The value for 'dss_signature_blob' is encoded as a string containing + // r, followed by s (which are 160-bit integers, without lengths or + // padding, unsigned, and in network byte order). + // For DSS purposes, sig.Blob should be exactly 40 bytes in length. + if len(sig.Blob) != 40 { + return errors.New("ssh: DSA signature parse error") + } + r := new(big.Int).SetBytes(sig.Blob[:20]) + s := new(big.Int).SetBytes(sig.Blob[20:]) + if dsa.Verify((*dsa.PublicKey)(k), digest, r, s) { + return nil + } + return errors.New("ssh: signature did not verify") +} + +func (k *dsaPublicKey) CryptoPublicKey() crypto.PublicKey { + return (*dsa.PublicKey)(k) +} + +type dsaPrivateKey struct { + *dsa.PrivateKey +} + +func (k *dsaPrivateKey) PublicKey() PublicKey { + return (*dsaPublicKey)(&k.PrivateKey.PublicKey) +} + +func (k *dsaPrivateKey) Sign(rand io.Reader, data []byte) (*Signature, error) { + return k.SignWithAlgorithm(rand, data, k.PublicKey().Type()) +} + +func (k *dsaPrivateKey) Algorithms() []string { + return []string{k.PublicKey().Type()} +} + +func (k *dsaPrivateKey) SignWithAlgorithm(rand io.Reader, data []byte, algorithm string) (*Signature, error) { + if algorithm != "" && algorithm != k.PublicKey().Type() { + return nil, fmt.Errorf("ssh: unsupported signature algorithm %s", algorithm) + } + + h := hashFuncs[k.PublicKey().Type()].New() + h.Write(data) + digest := h.Sum(nil) + r, s, err := dsa.Sign(rand, k.PrivateKey, digest) + if err != nil { + return nil, err + } + + sig := make([]byte, 40) + rb := r.Bytes() + sb := s.Bytes() + + copy(sig[20-len(rb):20], rb) + copy(sig[40-len(sb):], sb) + + return &Signature{ + Format: k.PublicKey().Type(), + Blob: sig, + }, nil +} + +type ecdsaPublicKey ecdsa.PublicKey + +func (k *ecdsaPublicKey) Type() string { + return "ecdsa-sha2-" + k.nistID() +} + +func (k *ecdsaPublicKey) nistID() string { + switch k.Params().BitSize { + case 256: + return "nistp256" + case 384: + return "nistp384" + case 521: + return "nistp521" + } + panic("ssh: unsupported ecdsa key size") +} + +type ed25519PublicKey ed25519.PublicKey + +func (k ed25519PublicKey) Type() string { + return KeyAlgoED25519 +} + +func parseED25519(in []byte) (out PublicKey, rest []byte, err error) { + var w struct { + KeyBytes []byte + Rest []byte `ssh:"rest"` + } + + if err := Unmarshal(in, &w); err != nil { + return nil, nil, err + } + + if l := len(w.KeyBytes); l != ed25519.PublicKeySize { + return nil, nil, fmt.Errorf("invalid size %d for Ed25519 public key", l) + } + + return ed25519PublicKey(w.KeyBytes), w.Rest, nil +} + +func (k ed25519PublicKey) Marshal() []byte { + w := struct { + Name string + KeyBytes []byte + }{ + KeyAlgoED25519, + []byte(k), + } + return Marshal(&w) +} + +func (k ed25519PublicKey) Verify(b []byte, sig *Signature) error { + if sig.Format != k.Type() { + return fmt.Errorf("ssh: signature type %s for key type %s", sig.Format, k.Type()) + } + if l := len(k); l != ed25519.PublicKeySize { + return fmt.Errorf("ssh: invalid size %d for Ed25519 public key", l) + } + + if ok := ed25519.Verify(ed25519.PublicKey(k), b, sig.Blob); !ok { + return errors.New("ssh: signature did not verify") + } + + return nil +} + +func (k ed25519PublicKey) CryptoPublicKey() crypto.PublicKey { + return ed25519.PublicKey(k) +} + +func supportedEllipticCurve(curve elliptic.Curve) bool { + return curve == elliptic.P256() || curve == elliptic.P384() || curve == elliptic.P521() +} + +// parseECDSA parses an ECDSA key according to RFC 5656, section 3.1. +func parseECDSA(in []byte) (out PublicKey, rest []byte, err error) { + var w struct { + Curve string + KeyBytes []byte + Rest []byte `ssh:"rest"` + } + + if err := Unmarshal(in, &w); err != nil { + return nil, nil, err + } + + key := new(ecdsa.PublicKey) + + switch w.Curve { + case "nistp256": + key.Curve = elliptic.P256() + case "nistp384": + key.Curve = elliptic.P384() + case "nistp521": + key.Curve = elliptic.P521() + default: + return nil, nil, errors.New("ssh: unsupported curve") + } + + key.X, key.Y = elliptic.Unmarshal(key.Curve, w.KeyBytes) + if key.X == nil || key.Y == nil { + return nil, nil, errors.New("ssh: invalid curve point") + } + return (*ecdsaPublicKey)(key), w.Rest, nil +} + +func (k *ecdsaPublicKey) Marshal() []byte { + // See RFC 5656, section 3.1. + keyBytes := elliptic.Marshal(k.Curve, k.X, k.Y) + // ECDSA publickey struct layout should match the struct used by + // parseECDSACert in the x/crypto/ssh/agent package. + w := struct { + Name string + ID string + Key []byte + }{ + k.Type(), + k.nistID(), + keyBytes, + } + + return Marshal(&w) +} + +func (k *ecdsaPublicKey) Verify(data []byte, sig *Signature) error { + if sig.Format != k.Type() { + return fmt.Errorf("ssh: signature type %s for key type %s", sig.Format, k.Type()) + } + + h := hashFuncs[sig.Format].New() + h.Write(data) + digest := h.Sum(nil) + + // Per RFC 5656, section 3.1.2, + // The ecdsa_signature_blob value has the following specific encoding: + // mpint r + // mpint s + var ecSig struct { + R *big.Int + S *big.Int + } + + if err := Unmarshal(sig.Blob, &ecSig); err != nil { + return err + } + + if ecdsa.Verify((*ecdsa.PublicKey)(k), digest, ecSig.R, ecSig.S) { + return nil + } + return errors.New("ssh: signature did not verify") +} + +func (k *ecdsaPublicKey) CryptoPublicKey() crypto.PublicKey { + return (*ecdsa.PublicKey)(k) +} + +// skFields holds the additional fields present in U2F/FIDO2 signatures. +// See openssh/PROTOCOL.u2f 'SSH U2F Signatures' for details. +type skFields struct { + // Flags contains U2F/FIDO2 flags such as 'user present' + Flags byte + // Counter is a monotonic signature counter which can be + // used to detect concurrent use of a private key, should + // it be extracted from hardware. + Counter uint32 +} + +type skECDSAPublicKey struct { + // application is a URL-like string, typically "ssh:" for SSH. + // see openssh/PROTOCOL.u2f for details. + application string + ecdsa.PublicKey +} + +func (k *skECDSAPublicKey) Type() string { + return KeyAlgoSKECDSA256 +} + +func (k *skECDSAPublicKey) nistID() string { + return "nistp256" +} + +func parseSKECDSA(in []byte) (out PublicKey, rest []byte, err error) { + var w struct { + Curve string + KeyBytes []byte + Application string + Rest []byte `ssh:"rest"` + } + + if err := Unmarshal(in, &w); err != nil { + return nil, nil, err + } + + key := new(skECDSAPublicKey) + key.application = w.Application + + if w.Curve != "nistp256" { + return nil, nil, errors.New("ssh: unsupported curve") + } + key.Curve = elliptic.P256() + + key.X, key.Y = elliptic.Unmarshal(key.Curve, w.KeyBytes) + if key.X == nil || key.Y == nil { + return nil, nil, errors.New("ssh: invalid curve point") + } + + return key, w.Rest, nil +} + +func (k *skECDSAPublicKey) Marshal() []byte { + // See RFC 5656, section 3.1. + keyBytes := elliptic.Marshal(k.Curve, k.X, k.Y) + w := struct { + Name string + ID string + Key []byte + Application string + }{ + k.Type(), + k.nistID(), + keyBytes, + k.application, + } + + return Marshal(&w) +} + +func (k *skECDSAPublicKey) Verify(data []byte, sig *Signature) error { + if sig.Format != k.Type() { + return fmt.Errorf("ssh: signature type %s for key type %s", sig.Format, k.Type()) + } + + h := hashFuncs[sig.Format].New() + h.Write([]byte(k.application)) + appDigest := h.Sum(nil) + + h.Reset() + h.Write(data) + dataDigest := h.Sum(nil) + + var ecSig struct { + R *big.Int + S *big.Int + } + if err := Unmarshal(sig.Blob, &ecSig); err != nil { + return err + } + + var skf skFields + if err := Unmarshal(sig.Rest, &skf); err != nil { + return err + } + + blob := struct { + ApplicationDigest []byte `ssh:"rest"` + Flags byte + Counter uint32 + MessageDigest []byte `ssh:"rest"` + }{ + appDigest, + skf.Flags, + skf.Counter, + dataDigest, + } + + original := Marshal(blob) + + h.Reset() + h.Write(original) + digest := h.Sum(nil) + + if ecdsa.Verify((*ecdsa.PublicKey)(&k.PublicKey), digest, ecSig.R, ecSig.S) { + return nil + } + return errors.New("ssh: signature did not verify") +} + +func (k *skECDSAPublicKey) CryptoPublicKey() crypto.PublicKey { + return &k.PublicKey +} + +type skEd25519PublicKey struct { + // application is a URL-like string, typically "ssh:" for SSH. + // see openssh/PROTOCOL.u2f for details. + application string + ed25519.PublicKey +} + +func (k *skEd25519PublicKey) Type() string { + return KeyAlgoSKED25519 +} + +func parseSKEd25519(in []byte) (out PublicKey, rest []byte, err error) { + var w struct { + KeyBytes []byte + Application string + Rest []byte `ssh:"rest"` + } + + if err := Unmarshal(in, &w); err != nil { + return nil, nil, err + } + + if l := len(w.KeyBytes); l != ed25519.PublicKeySize { + return nil, nil, fmt.Errorf("invalid size %d for Ed25519 public key", l) + } + + key := new(skEd25519PublicKey) + key.application = w.Application + key.PublicKey = ed25519.PublicKey(w.KeyBytes) + + return key, w.Rest, nil +} + +func (k *skEd25519PublicKey) Marshal() []byte { + w := struct { + Name string + KeyBytes []byte + Application string + }{ + KeyAlgoSKED25519, + []byte(k.PublicKey), + k.application, + } + return Marshal(&w) +} + +func (k *skEd25519PublicKey) Verify(data []byte, sig *Signature) error { + if sig.Format != k.Type() { + return fmt.Errorf("ssh: signature type %s for key type %s", sig.Format, k.Type()) + } + if l := len(k.PublicKey); l != ed25519.PublicKeySize { + return fmt.Errorf("invalid size %d for Ed25519 public key", l) + } + + h := hashFuncs[sig.Format].New() + h.Write([]byte(k.application)) + appDigest := h.Sum(nil) + + h.Reset() + h.Write(data) + dataDigest := h.Sum(nil) + + var edSig struct { + Signature []byte `ssh:"rest"` + } + + if err := Unmarshal(sig.Blob, &edSig); err != nil { + return err + } + + var skf skFields + if err := Unmarshal(sig.Rest, &skf); err != nil { + return err + } + + blob := struct { + ApplicationDigest []byte `ssh:"rest"` + Flags byte + Counter uint32 + MessageDigest []byte `ssh:"rest"` + }{ + appDigest, + skf.Flags, + skf.Counter, + dataDigest, + } + + original := Marshal(blob) + + if ok := ed25519.Verify(k.PublicKey, original, edSig.Signature); !ok { + return errors.New("ssh: signature did not verify") + } + + return nil +} + +func (k *skEd25519PublicKey) CryptoPublicKey() crypto.PublicKey { + return k.PublicKey +} + +// NewSignerFromKey takes an *rsa.PrivateKey, *dsa.PrivateKey, +// *ecdsa.PrivateKey or any other crypto.Signer and returns a +// corresponding Signer instance. ECDSA keys must use P-256, P-384 or +// P-521. DSA keys must use parameter size L1024N160. +func NewSignerFromKey(key interface{}) (Signer, error) { + switch key := key.(type) { + case crypto.Signer: + return NewSignerFromSigner(key) + case *dsa.PrivateKey: + return newDSAPrivateKey(key) + default: + return nil, fmt.Errorf("ssh: unsupported key type %T", key) + } +} + +func newDSAPrivateKey(key *dsa.PrivateKey) (Signer, error) { + if err := checkDSAParams(&key.PublicKey.Parameters); err != nil { + return nil, err + } + + return &dsaPrivateKey{key}, nil +} + +type wrappedSigner struct { + signer crypto.Signer + pubKey PublicKey +} + +// NewSignerFromSigner takes any crypto.Signer implementation and +// returns a corresponding Signer interface. This can be used, for +// example, with keys kept in hardware modules. +func NewSignerFromSigner(signer crypto.Signer) (Signer, error) { + pubKey, err := NewPublicKey(signer.Public()) + if err != nil { + return nil, err + } + + return &wrappedSigner{signer, pubKey}, nil +} + +func (s *wrappedSigner) PublicKey() PublicKey { + return s.pubKey +} + +func (s *wrappedSigner) Sign(rand io.Reader, data []byte) (*Signature, error) { + return s.SignWithAlgorithm(rand, data, s.pubKey.Type()) +} + +func (s *wrappedSigner) Algorithms() []string { + return algorithmsForKeyFormat(s.pubKey.Type()) +} + +func (s *wrappedSigner) SignWithAlgorithm(rand io.Reader, data []byte, algorithm string) (*Signature, error) { + if algorithm == "" { + algorithm = s.pubKey.Type() + } + + if !contains(s.Algorithms(), algorithm) { + return nil, fmt.Errorf("ssh: unsupported signature algorithm %q for key format %q", algorithm, s.pubKey.Type()) + } + + hashFunc := hashFuncs[algorithm] + var digest []byte + if hashFunc != 0 { + h := hashFunc.New() + h.Write(data) + digest = h.Sum(nil) + } else { + digest = data + } + + signature, err := s.signer.Sign(rand, digest, hashFunc) + if err != nil { + return nil, err + } + + // crypto.Signer.Sign is expected to return an ASN.1-encoded signature + // for ECDSA and DSA, but that's not the encoding expected by SSH, so + // re-encode. + switch s.pubKey.(type) { + case *ecdsaPublicKey, *dsaPublicKey: + type asn1Signature struct { + R, S *big.Int + } + asn1Sig := new(asn1Signature) + _, err := asn1.Unmarshal(signature, asn1Sig) + if err != nil { + return nil, err + } + + switch s.pubKey.(type) { + case *ecdsaPublicKey: + signature = Marshal(asn1Sig) + + case *dsaPublicKey: + signature = make([]byte, 40) + r := asn1Sig.R.Bytes() + s := asn1Sig.S.Bytes() + copy(signature[20-len(r):20], r) + copy(signature[40-len(s):40], s) + } + } + + return &Signature{ + Format: algorithm, + Blob: signature, + }, nil +} + +// NewPublicKey takes an *rsa.PublicKey, *dsa.PublicKey, *ecdsa.PublicKey, +// or ed25519.PublicKey returns a corresponding PublicKey instance. +// ECDSA keys must use P-256, P-384 or P-521. +func NewPublicKey(key interface{}) (PublicKey, error) { + switch key := key.(type) { + case *rsa.PublicKey: + return (*rsaPublicKey)(key), nil + case *ecdsa.PublicKey: + if !supportedEllipticCurve(key.Curve) { + return nil, errors.New("ssh: only P-256, P-384 and P-521 EC keys are supported") + } + return (*ecdsaPublicKey)(key), nil + case *dsa.PublicKey: + return (*dsaPublicKey)(key), nil + case ed25519.PublicKey: + if l := len(key); l != ed25519.PublicKeySize { + return nil, fmt.Errorf("ssh: invalid size %d for Ed25519 public key", l) + } + return ed25519PublicKey(key), nil + default: + return nil, fmt.Errorf("ssh: unsupported key type %T", key) + } +} + +// ParsePrivateKey returns a Signer from a PEM encoded private key. It supports +// the same keys as ParseRawPrivateKey. If the private key is encrypted, it +// will return a PassphraseMissingError. +func ParsePrivateKey(pemBytes []byte) (Signer, error) { + key, err := ParseRawPrivateKey(pemBytes) + if err != nil { + return nil, err + } + + return NewSignerFromKey(key) +} + +// encryptedBlock tells whether a private key is +// encrypted by examining its Proc-Type header +// for a mention of ENCRYPTED +// according to RFC 1421 Section 4.6.1.1. +func encryptedBlock(block *pem.Block) bool { + return strings.Contains(block.Headers["Proc-Type"], "ENCRYPTED") +} + +// A PassphraseMissingError indicates that parsing this private key requires a +// passphrase. Use ParsePrivateKeyWithPassphrase. +type PassphraseMissingError struct { + // PublicKey will be set if the private key format includes an unencrypted + // public key along with the encrypted private key. + PublicKey PublicKey +} + +func (*PassphraseMissingError) Error() string { + return "ssh: this private key is passphrase protected" +} + +// ParseRawPrivateKey returns a private key from a PEM encoded private key. It supports +// RSA, DSA, ECDSA, and Ed25519 private keys in PKCS#1, PKCS#8, OpenSSL, and OpenSSH +// formats. If the private key is encrypted, it will return a PassphraseMissingError. +func ParseRawPrivateKey(pemBytes []byte) (interface{}, error) { + block, _ := pem.Decode(pemBytes) + if block == nil { + return nil, errors.New("ssh: no key found") + } + + if encryptedBlock(block) { + return nil, &PassphraseMissingError{} + } + + switch block.Type { + case "RSA PRIVATE KEY": + return x509.ParsePKCS1PrivateKey(block.Bytes) + // RFC5208 - https://tools.ietf.org/html/rfc5208 + case "PRIVATE KEY": + return x509.ParsePKCS8PrivateKey(block.Bytes) + case "EC PRIVATE KEY": + return x509.ParseECPrivateKey(block.Bytes) + case "DSA PRIVATE KEY": + return ParseDSAPrivateKey(block.Bytes) + case "OPENSSH PRIVATE KEY": + return parseOpenSSHPrivateKey(block.Bytes, unencryptedOpenSSHKey) + default: + return nil, fmt.Errorf("ssh: unsupported key type %q", block.Type) + } +} + +// ParseDSAPrivateKey returns a DSA private key from its ASN.1 DER encoding, as +// specified by the OpenSSL DSA man page. +func ParseDSAPrivateKey(der []byte) (*dsa.PrivateKey, error) { + var k struct { + Version int + P *big.Int + Q *big.Int + G *big.Int + Pub *big.Int + Priv *big.Int + } + rest, err := asn1.Unmarshal(der, &k) + if err != nil { + return nil, errors.New("ssh: failed to parse DSA key: " + err.Error()) + } + if len(rest) > 0 { + return nil, errors.New("ssh: garbage after DSA key") + } + + return &dsa.PrivateKey{ + PublicKey: dsa.PublicKey{ + Parameters: dsa.Parameters{ + P: k.P, + Q: k.Q, + G: k.G, + }, + Y: k.Pub, + }, + X: k.Priv, + }, nil +} + +func unencryptedOpenSSHKey(cipherName, kdfName, kdfOpts string, privKeyBlock []byte) ([]byte, error) { + if kdfName != "none" || cipherName != "none" { + return nil, &PassphraseMissingError{} + } + if kdfOpts != "" { + return nil, errors.New("ssh: invalid openssh private key") + } + return privKeyBlock, nil +} + +func unencryptedOpenSSHMarshaler(privKeyBlock []byte) ([]byte, string, string, string, error) { + key := generateOpenSSHPadding(privKeyBlock, 8) + return key, "none", "none", "", nil +} + +const privateKeyAuthMagic = "openssh-key-v1\x00" + +type openSSHDecryptFunc func(CipherName, KdfName, KdfOpts string, PrivKeyBlock []byte) ([]byte, error) +type openSSHEncryptFunc func(PrivKeyBlock []byte) (ProtectedKeyBlock []byte, cipherName, kdfName, kdfOptions string, err error) + +type openSSHEncryptedPrivateKey struct { + CipherName string + KdfName string + KdfOpts string + NumKeys uint32 + PubKey []byte + PrivKeyBlock []byte +} + +type openSSHPrivateKey struct { + Check1 uint32 + Check2 uint32 + Keytype string + Rest []byte `ssh:"rest"` +} + +type openSSHRSAPrivateKey struct { + N *big.Int + E *big.Int + D *big.Int + Iqmp *big.Int + P *big.Int + Q *big.Int + Comment string + Pad []byte `ssh:"rest"` +} + +type openSSHEd25519PrivateKey struct { + Pub []byte + Priv []byte + Comment string + Pad []byte `ssh:"rest"` +} + +type openSSHECDSAPrivateKey struct { + Curve string + Pub []byte + D *big.Int + Comment string + Pad []byte `ssh:"rest"` +} + +// parseOpenSSHPrivateKey parses an OpenSSH private key, using the decrypt +// function to unwrap the encrypted portion. unencryptedOpenSSHKey can be used +// as the decrypt function to parse an unencrypted private key. See +// https://github.com/openssh/openssh-portable/blob/master/PROTOCOL.key. +func parseOpenSSHPrivateKey(key []byte, decrypt openSSHDecryptFunc) (crypto.PrivateKey, error) { + if len(key) < len(privateKeyAuthMagic) || string(key[:len(privateKeyAuthMagic)]) != privateKeyAuthMagic { + return nil, errors.New("ssh: invalid openssh private key format") + } + remaining := key[len(privateKeyAuthMagic):] + + var w openSSHEncryptedPrivateKey + if err := Unmarshal(remaining, &w); err != nil { + return nil, err + } + if w.NumKeys != 1 { + // We only support single key files, and so does OpenSSH. + // https://github.com/openssh/openssh-portable/blob/4103a3ec7/sshkey.c#L4171 + return nil, errors.New("ssh: multi-key files are not supported") + } + + privKeyBlock, err := decrypt(w.CipherName, w.KdfName, w.KdfOpts, w.PrivKeyBlock) + if err != nil { + if err, ok := err.(*PassphraseMissingError); ok { + pub, errPub := ParsePublicKey(w.PubKey) + if errPub != nil { + return nil, fmt.Errorf("ssh: failed to parse embedded public key: %v", errPub) + } + err.PublicKey = pub + } + return nil, err + } + + var pk1 openSSHPrivateKey + if err := Unmarshal(privKeyBlock, &pk1); err != nil || pk1.Check1 != pk1.Check2 { + if w.CipherName != "none" { + return nil, x509.IncorrectPasswordError + } + return nil, errors.New("ssh: malformed OpenSSH key") + } + + switch pk1.Keytype { + case KeyAlgoRSA: + var key openSSHRSAPrivateKey + if err := Unmarshal(pk1.Rest, &key); err != nil { + return nil, err + } + + if err := checkOpenSSHKeyPadding(key.Pad); err != nil { + return nil, err + } + + pk := &rsa.PrivateKey{ + PublicKey: rsa.PublicKey{ + N: key.N, + E: int(key.E.Int64()), + }, + D: key.D, + Primes: []*big.Int{key.P, key.Q}, + } + + if err := pk.Validate(); err != nil { + return nil, err + } + + pk.Precompute() + + return pk, nil + case KeyAlgoED25519: + var key openSSHEd25519PrivateKey + if err := Unmarshal(pk1.Rest, &key); err != nil { + return nil, err + } + + if len(key.Priv) != ed25519.PrivateKeySize { + return nil, errors.New("ssh: private key unexpected length") + } + + if err := checkOpenSSHKeyPadding(key.Pad); err != nil { + return nil, err + } + + pk := ed25519.PrivateKey(make([]byte, ed25519.PrivateKeySize)) + copy(pk, key.Priv) + return &pk, nil + case KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521: + var key openSSHECDSAPrivateKey + if err := Unmarshal(pk1.Rest, &key); err != nil { + return nil, err + } + + if err := checkOpenSSHKeyPadding(key.Pad); err != nil { + return nil, err + } + + var curve elliptic.Curve + switch key.Curve { + case "nistp256": + curve = elliptic.P256() + case "nistp384": + curve = elliptic.P384() + case "nistp521": + curve = elliptic.P521() + default: + return nil, errors.New("ssh: unhandled elliptic curve: " + key.Curve) + } + + X, Y := elliptic.Unmarshal(curve, key.Pub) + if X == nil || Y == nil { + return nil, errors.New("ssh: failed to unmarshal public key") + } + + if key.D.Cmp(curve.Params().N) >= 0 { + return nil, errors.New("ssh: scalar is out of range") + } + + x, y := curve.ScalarBaseMult(key.D.Bytes()) + if x.Cmp(X) != 0 || y.Cmp(Y) != 0 { + return nil, errors.New("ssh: public key does not match private key") + } + + return &ecdsa.PrivateKey{ + PublicKey: ecdsa.PublicKey{ + Curve: curve, + X: X, + Y: Y, + }, + D: key.D, + }, nil + default: + return nil, errors.New("ssh: unhandled key type") + } +} + +func marshalOpenSSHPrivateKey(key crypto.PrivateKey, comment string, encrypt openSSHEncryptFunc) (*pem.Block, error) { + var w openSSHEncryptedPrivateKey + var pk1 openSSHPrivateKey + + // Random check bytes. + var check uint32 + if err := binary.Read(rand.Reader, binary.BigEndian, &check); err != nil { + return nil, err + } + + pk1.Check1 = check + pk1.Check2 = check + w.NumKeys = 1 + + // Use a []byte directly on ed25519 keys. + if k, ok := key.(*ed25519.PrivateKey); ok { + key = *k + } + + switch k := key.(type) { + case *rsa.PrivateKey: + E := new(big.Int).SetInt64(int64(k.PublicKey.E)) + // Marshal public key: + // E and N are in reversed order in the public and private key. + pubKey := struct { + KeyType string + E *big.Int + N *big.Int + }{ + KeyAlgoRSA, + E, k.PublicKey.N, + } + w.PubKey = Marshal(pubKey) + + // Marshal private key. + key := openSSHRSAPrivateKey{ + N: k.PublicKey.N, + E: E, + D: k.D, + Iqmp: k.Precomputed.Qinv, + P: k.Primes[0], + Q: k.Primes[1], + Comment: comment, + } + pk1.Keytype = KeyAlgoRSA + pk1.Rest = Marshal(key) + case ed25519.PrivateKey: + pub := make([]byte, ed25519.PublicKeySize) + priv := make([]byte, ed25519.PrivateKeySize) + copy(pub, k[32:]) + copy(priv, k) + + // Marshal public key. + pubKey := struct { + KeyType string + Pub []byte + }{ + KeyAlgoED25519, pub, + } + w.PubKey = Marshal(pubKey) + + // Marshal private key. + key := openSSHEd25519PrivateKey{ + Pub: pub, + Priv: priv, + Comment: comment, + } + pk1.Keytype = KeyAlgoED25519 + pk1.Rest = Marshal(key) + case *ecdsa.PrivateKey: + var curve, keyType string + switch name := k.Curve.Params().Name; name { + case "P-256": + curve = "nistp256" + keyType = KeyAlgoECDSA256 + case "P-384": + curve = "nistp384" + keyType = KeyAlgoECDSA384 + case "P-521": + curve = "nistp521" + keyType = KeyAlgoECDSA521 + default: + return nil, errors.New("ssh: unhandled elliptic curve " + name) + } + + pub := elliptic.Marshal(k.Curve, k.PublicKey.X, k.PublicKey.Y) + + // Marshal public key. + pubKey := struct { + KeyType string + Curve string + Pub []byte + }{ + keyType, curve, pub, + } + w.PubKey = Marshal(pubKey) + + // Marshal private key. + key := openSSHECDSAPrivateKey{ + Curve: curve, + Pub: pub, + D: k.D, + Comment: comment, + } + pk1.Keytype = keyType + pk1.Rest = Marshal(key) + default: + return nil, fmt.Errorf("ssh: unsupported key type %T", k) + } + + var err error + // Add padding and encrypt the key if necessary. + w.PrivKeyBlock, w.CipherName, w.KdfName, w.KdfOpts, err = encrypt(Marshal(pk1)) + if err != nil { + return nil, err + } + + b := Marshal(w) + block := &pem.Block{ + Type: "OPENSSH PRIVATE KEY", + Bytes: append([]byte(privateKeyAuthMagic), b...), + } + return block, nil +} + +func checkOpenSSHKeyPadding(pad []byte) error { + for i, b := range pad { + if int(b) != i+1 { + return errors.New("ssh: padding not as expected") + } + } + return nil +} + +func generateOpenSSHPadding(block []byte, blockSize int) []byte { + for i, l := 0, len(block); (l+i)%blockSize != 0; i++ { + block = append(block, byte(i+1)) + } + return block +} + +// FingerprintLegacyMD5 returns the user presentation of the key's +// fingerprint as described by RFC 4716 section 4. +func FingerprintLegacyMD5(pubKey PublicKey) string { + md5sum := md5.Sum(pubKey.Marshal()) + hexarray := make([]string, len(md5sum)) + for i, c := range md5sum { + hexarray[i] = hex.EncodeToString([]byte{c}) + } + return strings.Join(hexarray, ":") +} + +// FingerprintSHA256 returns the user presentation of the key's +// fingerprint as unpadded base64 encoded sha256 hash. +// This format was introduced from OpenSSH 6.8. +// https://www.openssh.com/txt/release-6.8 +// https://tools.ietf.org/html/rfc4648#section-3.2 (unpadded base64 encoding) +func FingerprintSHA256(pubKey PublicKey) string { + sha256sum := sha256.Sum256(pubKey.Marshal()) + hash := base64.RawStdEncoding.EncodeToString(sha256sum[:]) + return "SHA256:" + hash +} diff --git a/tempfork/sshtest/ssh/keys_test.go b/tempfork/sshtest/ssh/keys_test.go new file mode 100644 index 000000000..bf1f0be1b --- /dev/null +++ b/tempfork/sshtest/ssh/keys_test.go @@ -0,0 +1,724 @@ +// Copyright 2014 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "bytes" + "crypto/dsa" + "crypto/ecdsa" + "crypto/ed25519" + "crypto/elliptic" + "crypto/rand" + "crypto/rsa" + "encoding/base64" + "encoding/hex" + "encoding/pem" + "fmt" + "io" + "reflect" + "strings" + "testing" + + "golang.org/x/crypto/ssh/testdata" +) + +func rawKey(pub PublicKey) interface{} { + switch k := pub.(type) { + case *rsaPublicKey: + return (*rsa.PublicKey)(k) + case *dsaPublicKey: + return (*dsa.PublicKey)(k) + case *ecdsaPublicKey: + return (*ecdsa.PublicKey)(k) + case ed25519PublicKey: + return (ed25519.PublicKey)(k) + case *Certificate: + return k + } + panic("unknown key type") +} + +func TestKeyMarshalParse(t *testing.T) { + for _, priv := range testSigners { + pub := priv.PublicKey() + roundtrip, err := ParsePublicKey(pub.Marshal()) + if err != nil { + t.Errorf("ParsePublicKey(%T): %v", pub, err) + } + + k1 := rawKey(pub) + k2 := rawKey(roundtrip) + + if !reflect.DeepEqual(k1, k2) { + t.Errorf("got %#v in roundtrip, want %#v", k2, k1) + } + } +} + +func TestUnsupportedCurves(t *testing.T) { + raw, err := ecdsa.GenerateKey(elliptic.P224(), rand.Reader) + if err != nil { + t.Fatalf("GenerateKey: %v", err) + } + + if _, err = NewSignerFromKey(raw); err == nil || !strings.Contains(err.Error(), "only P-256") { + t.Fatalf("NewPrivateKey should not succeed with P-224, got: %v", err) + } + + if _, err = NewPublicKey(&raw.PublicKey); err == nil || !strings.Contains(err.Error(), "only P-256") { + t.Fatalf("NewPublicKey should not succeed with P-224, got: %v", err) + } +} + +func TestNewPublicKey(t *testing.T) { + for _, k := range testSigners { + raw := rawKey(k.PublicKey()) + // Skip certificates, as NewPublicKey does not support them. + if _, ok := raw.(*Certificate); ok { + continue + } + pub, err := NewPublicKey(raw) + if err != nil { + t.Errorf("NewPublicKey(%#v): %v", raw, err) + } + if !reflect.DeepEqual(k.PublicKey(), pub) { + t.Errorf("NewPublicKey(%#v) = %#v, want %#v", raw, pub, k.PublicKey()) + } + } +} + +func TestKeySignVerify(t *testing.T) { + for _, priv := range testSigners { + pub := priv.PublicKey() + + data := []byte("sign me") + sig, err := priv.Sign(rand.Reader, data) + if err != nil { + t.Fatalf("Sign(%T): %v", priv, err) + } + + if err := pub.Verify(data, sig); err != nil { + t.Errorf("publicKey.Verify(%T): %v", priv, err) + } + sig.Blob[5]++ + if err := pub.Verify(data, sig); err == nil { + t.Errorf("publicKey.Verify on broken sig did not fail") + } + } +} + +func TestKeySignWithAlgorithmVerify(t *testing.T) { + for k, priv := range testSigners { + if algorithmSigner, ok := priv.(MultiAlgorithmSigner); !ok { + t.Errorf("Signers %q constructed by ssh package should always implement the MultiAlgorithmSigner interface: %T", k, priv) + } else { + pub := priv.PublicKey() + data := []byte("sign me") + + signWithAlgTestCase := func(algorithm string, expectedAlg string) { + sig, err := algorithmSigner.SignWithAlgorithm(rand.Reader, data, algorithm) + if err != nil { + t.Fatalf("Sign(%T): %v", priv, err) + } + if sig.Format != expectedAlg { + t.Errorf("signature format did not match requested signature algorithm: %s != %s", sig.Format, expectedAlg) + } + + if err := pub.Verify(data, sig); err != nil { + t.Errorf("publicKey.Verify(%T): %v", priv, err) + } + sig.Blob[5]++ + if err := pub.Verify(data, sig); err == nil { + t.Errorf("publicKey.Verify on broken sig did not fail") + } + } + + // Using the empty string as the algorithm name should result in the same signature format as the algorithm-free Sign method. + defaultSig, err := priv.Sign(rand.Reader, data) + if err != nil { + t.Fatalf("Sign(%T): %v", priv, err) + } + signWithAlgTestCase("", defaultSig.Format) + + // RSA keys are the only ones which currently support more than one signing algorithm + if pub.Type() == KeyAlgoRSA { + for _, algorithm := range []string{KeyAlgoRSA, KeyAlgoRSASHA256, KeyAlgoRSASHA512} { + signWithAlgTestCase(algorithm, algorithm) + } + } + } + } +} + +func TestKeySignWithShortSignature(t *testing.T) { + signer := testSigners["rsa"].(AlgorithmSigner) + pub := signer.PublicKey() + // Note: data obtained by empirically trying until a result + // starting with 0 appeared + tests := []struct { + algorithm string + data []byte + }{ + { + algorithm: KeyAlgoRSA, + data: []byte("sign me92"), + }, + { + algorithm: KeyAlgoRSASHA256, + data: []byte("sign me294"), + }, + { + algorithm: KeyAlgoRSASHA512, + data: []byte("sign me60"), + }, + } + + for _, tt := range tests { + sig, err := signer.SignWithAlgorithm(rand.Reader, tt.data, tt.algorithm) + if err != nil { + t.Fatalf("Sign(%T): %v", signer, err) + } + if sig.Blob[0] != 0 { + t.Errorf("%s: Expected signature with a leading 0", tt.algorithm) + } + sig.Blob = sig.Blob[1:] + if err := pub.Verify(tt.data, sig); err != nil { + t.Errorf("publicKey.Verify(%s): %v", tt.algorithm, err) + } + } +} + +func TestParseRSAPrivateKey(t *testing.T) { + key := testPrivateKeys["rsa"] + + rsa, ok := key.(*rsa.PrivateKey) + if !ok { + t.Fatalf("got %T, want *rsa.PrivateKey", rsa) + } + + if err := rsa.Validate(); err != nil { + t.Errorf("Validate: %v", err) + } +} + +func TestParseECPrivateKey(t *testing.T) { + key := testPrivateKeys["ecdsa"] + + ecKey, ok := key.(*ecdsa.PrivateKey) + if !ok { + t.Fatalf("got %T, want *ecdsa.PrivateKey", ecKey) + } + + if !validateECPublicKey(ecKey.Curve, ecKey.X, ecKey.Y) { + t.Fatalf("public key does not validate.") + } +} + +func TestParseDSA(t *testing.T) { + // We actually exercise the ParsePrivateKey codepath here, as opposed to + // using the ParseRawPrivateKey+NewSignerFromKey path that testdata_test.go + // uses. + s, err := ParsePrivateKey(testdata.PEMBytes["dsa"]) + if err != nil { + t.Fatalf("ParsePrivateKey returned error: %s", err) + } + + data := []byte("sign me") + sig, err := s.Sign(rand.Reader, data) + if err != nil { + t.Fatalf("dsa.Sign: %v", err) + } + + if err := s.PublicKey().Verify(data, sig); err != nil { + t.Errorf("Verify failed: %v", err) + } +} + +// Tests for authorized_keys parsing. + +// getTestKey returns a public key, and its base64 encoding. +func getTestKey() (PublicKey, string) { + k := testPublicKeys["rsa"] + + b := &bytes.Buffer{} + e := base64.NewEncoder(base64.StdEncoding, b) + e.Write(k.Marshal()) + e.Close() + + return k, b.String() +} + +func TestMarshalParsePublicKey(t *testing.T) { + pub, pubSerialized := getTestKey() + line := fmt.Sprintf("%s %s user@host", pub.Type(), pubSerialized) + + authKeys := MarshalAuthorizedKey(pub) + actualFields := strings.Fields(string(authKeys)) + if len(actualFields) == 0 { + t.Fatalf("failed authKeys: %v", authKeys) + } + + // drop the comment + expectedFields := strings.Fields(line)[0:2] + + if !reflect.DeepEqual(actualFields, expectedFields) { + t.Errorf("got %v, expected %v", actualFields, expectedFields) + } + + actPub, _, _, _, err := ParseAuthorizedKey([]byte(line)) + if err != nil { + t.Fatalf("cannot parse %v: %v", line, err) + } + if !reflect.DeepEqual(actPub, pub) { + t.Errorf("got %v, expected %v", actPub, pub) + } +} + +func TestMarshalPrivateKey(t *testing.T) { + tests := []struct { + name string + }{ + {"rsa-openssh-format"}, + {"ed25519"}, + {"p256-openssh-format"}, + {"p384-openssh-format"}, + {"p521-openssh-format"}, + } + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + expected, ok := testPrivateKeys[tt.name] + if !ok { + t.Fatalf("cannot find key %s", tt.name) + } + + block, err := MarshalPrivateKey(expected, "test@golang.org") + if err != nil { + t.Fatalf("cannot marshal %s: %v", tt.name, err) + } + + key, err := ParseRawPrivateKey(pem.EncodeToMemory(block)) + if err != nil { + t.Fatalf("cannot parse %s: %v", tt.name, err) + } + + if !reflect.DeepEqual(expected, key) { + t.Errorf("unexpected marshaled key %s", tt.name) + } + }) + } +} + +type testAuthResult struct { + pubKey PublicKey + options []string + comments string + rest string + ok bool +} + +func testAuthorizedKeys(t *testing.T, authKeys []byte, expected []testAuthResult) { + rest := authKeys + var values []testAuthResult + for len(rest) > 0 { + var r testAuthResult + var err error + r.pubKey, r.comments, r.options, rest, err = ParseAuthorizedKey(rest) + r.ok = (err == nil) + t.Log(err) + r.rest = string(rest) + values = append(values, r) + } + + if !reflect.DeepEqual(values, expected) { + t.Errorf("got %#v, expected %#v", values, expected) + } +} + +func TestAuthorizedKeyBasic(t *testing.T) { + pub, pubSerialized := getTestKey() + line := "ssh-rsa " + pubSerialized + " user@host" + testAuthorizedKeys(t, []byte(line), + []testAuthResult{ + {pub, nil, "user@host", "", true}, + }) +} + +func TestAuth(t *testing.T) { + pub, pubSerialized := getTestKey() + authWithOptions := []string{ + `# comments to ignore before any keys...`, + ``, + `env="HOME=/home/root",no-port-forwarding ssh-rsa ` + pubSerialized + ` user@host`, + `# comments to ignore, along with a blank line`, + ``, + `env="HOME=/home/root2" ssh-rsa ` + pubSerialized + ` user2@host2`, + ``, + `# more comments, plus a invalid entry`, + `ssh-rsa data-that-will-not-parse user@host3`, + } + for _, eol := range []string{"\n", "\r\n"} { + authOptions := strings.Join(authWithOptions, eol) + rest2 := strings.Join(authWithOptions[3:], eol) + rest3 := strings.Join(authWithOptions[6:], eol) + testAuthorizedKeys(t, []byte(authOptions), []testAuthResult{ + {pub, []string{`env="HOME=/home/root"`, "no-port-forwarding"}, "user@host", rest2, true}, + {pub, []string{`env="HOME=/home/root2"`}, "user2@host2", rest3, true}, + {nil, nil, "", "", false}, + }) + } +} + +func TestAuthWithQuotedSpaceInEnv(t *testing.T) { + pub, pubSerialized := getTestKey() + authWithQuotedSpaceInEnv := []byte(`env="HOME=/home/root dir",no-port-forwarding ssh-rsa ` + pubSerialized + ` user@host`) + testAuthorizedKeys(t, []byte(authWithQuotedSpaceInEnv), []testAuthResult{ + {pub, []string{`env="HOME=/home/root dir"`, "no-port-forwarding"}, "user@host", "", true}, + }) +} + +func TestAuthWithQuotedCommaInEnv(t *testing.T) { + pub, pubSerialized := getTestKey() + authWithQuotedCommaInEnv := []byte(`env="HOME=/home/root,dir",no-port-forwarding ssh-rsa ` + pubSerialized + ` user@host`) + testAuthorizedKeys(t, []byte(authWithQuotedCommaInEnv), []testAuthResult{ + {pub, []string{`env="HOME=/home/root,dir"`, "no-port-forwarding"}, "user@host", "", true}, + }) +} + +func TestAuthWithQuotedQuoteInEnv(t *testing.T) { + pub, pubSerialized := getTestKey() + authWithQuotedQuoteInEnv := []byte(`env="HOME=/home/\"root dir",no-port-forwarding` + "\t" + `ssh-rsa` + "\t" + pubSerialized + ` user@host`) + authWithDoubleQuotedQuote := []byte(`no-port-forwarding,env="HOME=/home/ \"root dir\"" ssh-rsa ` + pubSerialized + "\t" + `user@host`) + testAuthorizedKeys(t, []byte(authWithQuotedQuoteInEnv), []testAuthResult{ + {pub, []string{`env="HOME=/home/\"root dir"`, "no-port-forwarding"}, "user@host", "", true}, + }) + + testAuthorizedKeys(t, []byte(authWithDoubleQuotedQuote), []testAuthResult{ + {pub, []string{"no-port-forwarding", `env="HOME=/home/ \"root dir\""`}, "user@host", "", true}, + }) +} + +func TestAuthWithInvalidSpace(t *testing.T) { + _, pubSerialized := getTestKey() + authWithInvalidSpace := []byte(`env="HOME=/home/root dir", no-port-forwarding ssh-rsa ` + pubSerialized + ` user@host +#more to follow but still no valid keys`) + testAuthorizedKeys(t, []byte(authWithInvalidSpace), []testAuthResult{ + {nil, nil, "", "", false}, + }) +} + +func TestAuthWithMissingQuote(t *testing.T) { + pub, pubSerialized := getTestKey() + authWithMissingQuote := []byte(`env="HOME=/home/root,no-port-forwarding ssh-rsa ` + pubSerialized + ` user@host +env="HOME=/home/root",shared-control ssh-rsa ` + pubSerialized + ` user@host`) + + testAuthorizedKeys(t, []byte(authWithMissingQuote), []testAuthResult{ + {pub, []string{`env="HOME=/home/root"`, `shared-control`}, "user@host", "", true}, + }) +} + +func TestInvalidEntry(t *testing.T) { + authInvalid := []byte(`ssh-rsa`) + _, _, _, _, err := ParseAuthorizedKey(authInvalid) + if err == nil { + t.Errorf("got valid entry for %q", authInvalid) + } +} + +var knownHostsParseTests = []struct { + input string + err string + + marker string + comment string + hosts []string + rest string +}{ + { + "", + "EOF", + + "", "", nil, "", + }, + { + "# Just a comment", + "EOF", + + "", "", nil, "", + }, + { + " \t ", + "EOF", + + "", "", nil, "", + }, + { + "localhost ssh-rsa {RSAPUB}", + "", + + "", "", []string{"localhost"}, "", + }, + { + "localhost\tssh-rsa {RSAPUB}", + "", + + "", "", []string{"localhost"}, "", + }, + { + "localhost\tssh-rsa {RSAPUB}\tcomment comment", + "", + + "", "comment comment", []string{"localhost"}, "", + }, + { + "localhost\tssh-rsa {RSAPUB}\tcomment comment\n", + "", + + "", "comment comment", []string{"localhost"}, "", + }, + { + "localhost\tssh-rsa {RSAPUB}\tcomment comment\r\n", + "", + + "", "comment comment", []string{"localhost"}, "", + }, + { + "localhost\tssh-rsa {RSAPUB}\tcomment comment\r\nnext line", + "", + + "", "comment comment", []string{"localhost"}, "next line", + }, + { + "localhost,[host2:123]\tssh-rsa {RSAPUB}\tcomment comment", + "", + + "", "comment comment", []string{"localhost", "[host2:123]"}, "", + }, + { + "@marker \tlocalhost,[host2:123]\tssh-rsa {RSAPUB}", + "", + + "marker", "", []string{"localhost", "[host2:123]"}, "", + }, + { + "@marker \tlocalhost,[host2:123]\tssh-rsa aabbccdd", + "short read", + + "", "", nil, "", + }, +} + +func TestKnownHostsParsing(t *testing.T) { + rsaPub, rsaPubSerialized := getTestKey() + + for i, test := range knownHostsParseTests { + var expectedKey PublicKey + const rsaKeyToken = "{RSAPUB}" + + input := test.input + if strings.Contains(input, rsaKeyToken) { + expectedKey = rsaPub + input = strings.Replace(test.input, rsaKeyToken, rsaPubSerialized, -1) + } + + marker, hosts, pubKey, comment, rest, err := ParseKnownHosts([]byte(input)) + if err != nil { + if len(test.err) == 0 { + t.Errorf("#%d: unexpectedly failed with %q", i, err) + } else if !strings.Contains(err.Error(), test.err) { + t.Errorf("#%d: expected error containing %q, but got %q", i, test.err, err) + } + continue + } else if len(test.err) != 0 { + t.Errorf("#%d: succeeded but expected error including %q", i, test.err) + continue + } + + if !reflect.DeepEqual(expectedKey, pubKey) { + t.Errorf("#%d: expected key %#v, but got %#v", i, expectedKey, pubKey) + } + + if marker != test.marker { + t.Errorf("#%d: expected marker %q, but got %q", i, test.marker, marker) + } + + if comment != test.comment { + t.Errorf("#%d: expected comment %q, but got %q", i, test.comment, comment) + } + + if !reflect.DeepEqual(test.hosts, hosts) { + t.Errorf("#%d: expected hosts %#v, but got %#v", i, test.hosts, hosts) + } + + if rest := string(rest); rest != test.rest { + t.Errorf("#%d: expected remaining input to be %q, but got %q", i, test.rest, rest) + } + } +} + +func TestFingerprintLegacyMD5(t *testing.T) { + pub, _ := getTestKey() + fingerprint := FingerprintLegacyMD5(pub) + want := "b7:ef:d3:d5:89:29:52:96:9f:df:47:41:4d:15:37:f4" // ssh-keygen -lf -E md5 rsa + if fingerprint != want { + t.Errorf("got fingerprint %q want %q", fingerprint, want) + } +} + +func TestFingerprintSHA256(t *testing.T) { + pub, _ := getTestKey() + fingerprint := FingerprintSHA256(pub) + want := "SHA256:fi5+D7UmDZDE9Q2sAVvvlpcQSIakN4DERdINgXd2AnE" // ssh-keygen -lf rsa + if fingerprint != want { + t.Errorf("got fingerprint %q want %q", fingerprint, want) + } +} + +func TestInvalidKeys(t *testing.T) { + keyTypes := []string{ + "RSA PRIVATE KEY", + "PRIVATE KEY", + "EC PRIVATE KEY", + "DSA PRIVATE KEY", + "OPENSSH PRIVATE KEY", + } + + for _, keyType := range keyTypes { + for _, dataLen := range []int{0, 1, 2, 5, 10, 20} { + data := make([]byte, dataLen) + if _, err := io.ReadFull(rand.Reader, data); err != nil { + t.Fatal(err) + } + + var buf bytes.Buffer + pem.Encode(&buf, &pem.Block{ + Type: keyType, + Bytes: data, + }) + + // This test is just to ensure that the function + // doesn't panic so the return value is ignored. + ParseRawPrivateKey(buf.Bytes()) + } + } +} + +func TestSKKeys(t *testing.T) { + for _, d := range testdata.SKData { + pk, _, _, _, err := ParseAuthorizedKey(d.PubKey) + if err != nil { + t.Fatalf("parseAuthorizedKey returned error: %v", err) + } + + sigBuf := make([]byte, hex.DecodedLen(len(d.HexSignature))) + if _, err := hex.Decode(sigBuf, d.HexSignature); err != nil { + t.Fatalf("hex.Decode() failed: %v", err) + } + + dataBuf := make([]byte, hex.DecodedLen(len(d.HexData))) + if _, err := hex.Decode(dataBuf, d.HexData); err != nil { + t.Fatalf("hex.Decode() failed: %v", err) + } + + sig, _, ok := parseSignature(sigBuf) + if !ok { + t.Fatalf("parseSignature(%v) failed", sigBuf) + } + + // Test that good data and signature pass verification + if err := pk.Verify(dataBuf, sig); err != nil { + t.Errorf("%s: PublicKey.Verify(%v, %v) failed: %v", d.Name, dataBuf, sig, err) + } + + // Invalid data being passed in + invalidData := []byte("INVALID DATA") + if err := pk.Verify(invalidData, sig); err == nil { + t.Errorf("%s with invalid data: PublicKey.Verify(%v, %v) passed unexpectedly", d.Name, invalidData, sig) + } + + // Change byte in blob to corrup signature + sig.Blob[5] = byte('A') + // Corrupted data being passed in + if err := pk.Verify(dataBuf, sig); err == nil { + t.Errorf("%s with corrupted signature: PublicKey.Verify(%v, %v) passed unexpectedly", d.Name, dataBuf, sig) + } + } +} + +func TestNewSignerWithAlgos(t *testing.T) { + algorithSigner, ok := testSigners["rsa"].(AlgorithmSigner) + if !ok { + t.Fatal("rsa test signer does not implement the AlgorithmSigner interface") + } + _, err := NewSignerWithAlgorithms(algorithSigner, nil) + if err == nil { + t.Error("signer with algos created with no algorithms") + } + + _, err = NewSignerWithAlgorithms(algorithSigner, []string{KeyAlgoED25519}) + if err == nil { + t.Error("signer with algos created with invalid algorithms") + } + + _, err = NewSignerWithAlgorithms(algorithSigner, []string{CertAlgoRSASHA256v01}) + if err == nil { + t.Error("signer with algos created with certificate algorithms") + } + + mas, err := NewSignerWithAlgorithms(algorithSigner, []string{KeyAlgoRSASHA256, KeyAlgoRSASHA512}) + if err != nil { + t.Errorf("unable to create signer with valid algorithms: %v", err) + } + + _, err = NewSignerWithAlgorithms(mas, []string{KeyAlgoRSA}) + if err == nil { + t.Error("signer with algos created with restricted algorithms") + } +} + +func TestCryptoPublicKey(t *testing.T) { + for _, priv := range testSigners { + p1 := priv.PublicKey() + key, ok := p1.(CryptoPublicKey) + if !ok { + continue + } + p2, err := NewPublicKey(key.CryptoPublicKey()) + if err != nil { + t.Fatalf("NewPublicKey(CryptoPublicKey) failed for %s, got: %v", p1.Type(), err) + } + if !reflect.DeepEqual(p1, p2) { + t.Errorf("got %#v in NewPublicKey, want %#v", p2, p1) + } + } + for _, d := range testdata.SKData { + p1, _, _, _, err := ParseAuthorizedKey(d.PubKey) + if err != nil { + t.Fatalf("parseAuthorizedKey returned error: %v", err) + } + k1, ok := p1.(CryptoPublicKey) + if !ok { + t.Fatalf("%T does not implement CryptoPublicKey", p1) + } + + var p2 PublicKey + switch pub := k1.CryptoPublicKey().(type) { + case *ecdsa.PublicKey: + p2 = &skECDSAPublicKey{ + application: "ssh:", + PublicKey: *pub, + } + case ed25519.PublicKey: + p2 = &skEd25519PublicKey{ + application: "ssh:", + PublicKey: pub, + } + default: + t.Fatalf("unexpected type %T from CryptoPublicKey()", pub) + } + if !reflect.DeepEqual(p1, p2) { + t.Errorf("got %#v, want %#v", p2, p1) + } + } +} diff --git a/tempfork/sshtest/ssh/mac.go b/tempfork/sshtest/ssh/mac.go new file mode 100644 index 000000000..06a1b2750 --- /dev/null +++ b/tempfork/sshtest/ssh/mac.go @@ -0,0 +1,68 @@ +// Copyright 2012 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +// Message authentication support + +import ( + "crypto/hmac" + "crypto/sha1" + "crypto/sha256" + "crypto/sha512" + "hash" +) + +type macMode struct { + keySize int + etm bool + new func(key []byte) hash.Hash +} + +// truncatingMAC wraps around a hash.Hash and truncates the output digest to +// a given size. +type truncatingMAC struct { + length int + hmac hash.Hash +} + +func (t truncatingMAC) Write(data []byte) (int, error) { + return t.hmac.Write(data) +} + +func (t truncatingMAC) Sum(in []byte) []byte { + out := t.hmac.Sum(in) + return out[:len(in)+t.length] +} + +func (t truncatingMAC) Reset() { + t.hmac.Reset() +} + +func (t truncatingMAC) Size() int { + return t.length +} + +func (t truncatingMAC) BlockSize() int { return t.hmac.BlockSize() } + +var macModes = map[string]*macMode{ + "hmac-sha2-512-etm@openssh.com": {64, true, func(key []byte) hash.Hash { + return hmac.New(sha512.New, key) + }}, + "hmac-sha2-256-etm@openssh.com": {32, true, func(key []byte) hash.Hash { + return hmac.New(sha256.New, key) + }}, + "hmac-sha2-512": {64, false, func(key []byte) hash.Hash { + return hmac.New(sha512.New, key) + }}, + "hmac-sha2-256": {32, false, func(key []byte) hash.Hash { + return hmac.New(sha256.New, key) + }}, + "hmac-sha1": {20, false, func(key []byte) hash.Hash { + return hmac.New(sha1.New, key) + }}, + "hmac-sha1-96": {20, false, func(key []byte) hash.Hash { + return truncatingMAC{12, hmac.New(sha1.New, key)} + }}, +} diff --git a/tempfork/sshtest/ssh/mempipe_test.go b/tempfork/sshtest/ssh/mempipe_test.go new file mode 100644 index 000000000..f27339c51 --- /dev/null +++ b/tempfork/sshtest/ssh/mempipe_test.go @@ -0,0 +1,124 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "io" + "sync" + "testing" +) + +// An in-memory packetConn. It is safe to call Close and writePacket +// from different goroutines. +type memTransport struct { + eof bool + pending [][]byte + write *memTransport + writeCount uint64 + sync.Mutex + *sync.Cond +} + +func (t *memTransport) readPacket() ([]byte, error) { + t.Lock() + defer t.Unlock() + for { + if len(t.pending) > 0 { + r := t.pending[0] + t.pending = t.pending[1:] + return r, nil + } + if t.eof { + return nil, io.EOF + } + t.Cond.Wait() + } +} + +func (t *memTransport) closeSelf() error { + t.Lock() + defer t.Unlock() + if t.eof { + return io.EOF + } + t.eof = true + t.Cond.Broadcast() + return nil +} + +func (t *memTransport) Close() error { + err := t.write.closeSelf() + t.closeSelf() + return err +} + +func (t *memTransport) writePacket(p []byte) error { + t.write.Lock() + defer t.write.Unlock() + if t.write.eof { + return io.EOF + } + c := make([]byte, len(p)) + copy(c, p) + t.write.pending = append(t.write.pending, c) + t.write.Cond.Signal() + t.writeCount++ + return nil +} + +func (t *memTransport) getWriteCount() uint64 { + t.write.Lock() + defer t.write.Unlock() + return t.writeCount +} + +func memPipe() (a, b packetConn) { + t1 := memTransport{} + t2 := memTransport{} + t1.write = &t2 + t2.write = &t1 + t1.Cond = sync.NewCond(&t1.Mutex) + t2.Cond = sync.NewCond(&t2.Mutex) + return &t1, &t2 +} + +func TestMemPipe(t *testing.T) { + a, b := memPipe() + if err := a.writePacket([]byte{42}); err != nil { + t.Fatalf("writePacket: %v", err) + } + if wc := a.(*memTransport).getWriteCount(); wc != 1 { + t.Fatalf("got %v, want 1", wc) + } + if err := a.Close(); err != nil { + t.Fatal("Close: ", err) + } + p, err := b.readPacket() + if err != nil { + t.Fatal("readPacket: ", err) + } + if len(p) != 1 || p[0] != 42 { + t.Fatalf("got %v, want {42}", p) + } + p, err = b.readPacket() + if err != io.EOF { + t.Fatalf("got %v, %v, want EOF", p, err) + } + if wc := b.(*memTransport).getWriteCount(); wc != 0 { + t.Fatalf("got %v, want 0", wc) + } +} + +func TestDoubleClose(t *testing.T) { + a, _ := memPipe() + err := a.Close() + if err != nil { + t.Errorf("Close: %v", err) + } + err = a.Close() + if err != io.EOF { + t.Errorf("expect EOF on double close.") + } +} diff --git a/tempfork/sshtest/ssh/messages.go b/tempfork/sshtest/ssh/messages.go new file mode 100644 index 000000000..b55f86056 --- /dev/null +++ b/tempfork/sshtest/ssh/messages.go @@ -0,0 +1,891 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "bytes" + "encoding/binary" + "errors" + "fmt" + "io" + "math/big" + "reflect" + "strconv" + "strings" +) + +// These are SSH message type numbers. They are scattered around several +// documents but many were taken from [SSH-PARAMETERS]. +const ( + msgIgnore = 2 + msgUnimplemented = 3 + msgDebug = 4 + msgNewKeys = 21 +) + +// SSH messages: +// +// These structures mirror the wire format of the corresponding SSH messages. +// They are marshaled using reflection with the marshal and unmarshal functions +// in this file. The only wrinkle is that a final member of type []byte with a +// ssh tag of "rest" receives the remainder of a packet when unmarshaling. + +// See RFC 4253, section 11.1. +const msgDisconnect = 1 + +// disconnectMsg is the message that signals a disconnect. It is also +// the error type returned from mux.Wait() +type disconnectMsg struct { + Reason uint32 `sshtype:"1"` + Message string + Language string +} + +func (d *disconnectMsg) Error() string { + return fmt.Sprintf("ssh: disconnect, reason %d: %s", d.Reason, d.Message) +} + +// See RFC 4253, section 7.1. +const msgKexInit = 20 + +type kexInitMsg struct { + Cookie [16]byte `sshtype:"20"` + KexAlgos []string + ServerHostKeyAlgos []string + CiphersClientServer []string + CiphersServerClient []string + MACsClientServer []string + MACsServerClient []string + CompressionClientServer []string + CompressionServerClient []string + LanguagesClientServer []string + LanguagesServerClient []string + FirstKexFollows bool + Reserved uint32 +} + +// See RFC 4253, section 8. + +// Diffie-Hellman +const msgKexDHInit = 30 + +type kexDHInitMsg struct { + X *big.Int `sshtype:"30"` +} + +const msgKexECDHInit = 30 + +type kexECDHInitMsg struct { + ClientPubKey []byte `sshtype:"30"` +} + +const msgKexECDHReply = 31 + +type kexECDHReplyMsg struct { + HostKey []byte `sshtype:"31"` + EphemeralPubKey []byte + Signature []byte +} + +const msgKexDHReply = 31 + +type kexDHReplyMsg struct { + HostKey []byte `sshtype:"31"` + Y *big.Int + Signature []byte +} + +// See RFC 4419, section 5. +const msgKexDHGexGroup = 31 + +type kexDHGexGroupMsg struct { + P *big.Int `sshtype:"31"` + G *big.Int +} + +const msgKexDHGexInit = 32 + +type kexDHGexInitMsg struct { + X *big.Int `sshtype:"32"` +} + +const msgKexDHGexReply = 33 + +type kexDHGexReplyMsg struct { + HostKey []byte `sshtype:"33"` + Y *big.Int + Signature []byte +} + +const msgKexDHGexRequest = 34 + +type kexDHGexRequestMsg struct { + MinBits uint32 `sshtype:"34"` + PreferedBits uint32 + MaxBits uint32 +} + +// See RFC 4253, section 10. +const msgServiceRequest = 5 + +type serviceRequestMsg struct { + Service string `sshtype:"5"` +} + +// See RFC 4253, section 10. +const msgServiceAccept = 6 + +type serviceAcceptMsg struct { + Service string `sshtype:"6"` +} + +// See RFC 8308, section 2.3 +const msgExtInfo = 7 + +type extInfoMsg struct { + NumExtensions uint32 `sshtype:"7"` + Payload []byte `ssh:"rest"` +} + +// See RFC 4252, section 5. +const msgUserAuthRequest = 50 + +type userAuthRequestMsg struct { + User string `sshtype:"50"` + Service string + Method string + Payload []byte `ssh:"rest"` +} + +// Used for debug printouts of packets. +type userAuthSuccessMsg struct { +} + +// See RFC 4252, section 5.1 +const msgUserAuthFailure = 51 + +type userAuthFailureMsg struct { + Methods []string `sshtype:"51"` + PartialSuccess bool +} + +// See RFC 4252, section 5.1 +const msgUserAuthSuccess = 52 + +// See RFC 4252, section 5.4 +const msgUserAuthBanner = 53 + +type userAuthBannerMsg struct { + Message string `sshtype:"53"` + // unused, but required to allow message parsing + Language string +} + +// See RFC 4256, section 3.2 +const msgUserAuthInfoRequest = 60 +const msgUserAuthInfoResponse = 61 + +type userAuthInfoRequestMsg struct { + Name string `sshtype:"60"` + Instruction string + Language string + NumPrompts uint32 + Prompts []byte `ssh:"rest"` +} + +// See RFC 4254, section 5.1. +const msgChannelOpen = 90 + +type channelOpenMsg struct { + ChanType string `sshtype:"90"` + PeersID uint32 + PeersWindow uint32 + MaxPacketSize uint32 + TypeSpecificData []byte `ssh:"rest"` +} + +const msgChannelExtendedData = 95 +const msgChannelData = 94 + +// Used for debug print outs of packets. +type channelDataMsg struct { + PeersID uint32 `sshtype:"94"` + Length uint32 + Rest []byte `ssh:"rest"` +} + +// See RFC 4254, section 5.1. +const msgChannelOpenConfirm = 91 + +type channelOpenConfirmMsg struct { + PeersID uint32 `sshtype:"91"` + MyID uint32 + MyWindow uint32 + MaxPacketSize uint32 + TypeSpecificData []byte `ssh:"rest"` +} + +// See RFC 4254, section 5.1. +const msgChannelOpenFailure = 92 + +type channelOpenFailureMsg struct { + PeersID uint32 `sshtype:"92"` + Reason RejectionReason + Message string + Language string +} + +const msgChannelRequest = 98 + +type channelRequestMsg struct { + PeersID uint32 `sshtype:"98"` + Request string + WantReply bool + RequestSpecificData []byte `ssh:"rest"` +} + +// See RFC 4254, section 5.4. +const msgChannelSuccess = 99 + +type channelRequestSuccessMsg struct { + PeersID uint32 `sshtype:"99"` +} + +// See RFC 4254, section 5.4. +const msgChannelFailure = 100 + +type channelRequestFailureMsg struct { + PeersID uint32 `sshtype:"100"` +} + +// See RFC 4254, section 5.3 +const msgChannelClose = 97 + +type channelCloseMsg struct { + PeersID uint32 `sshtype:"97"` +} + +// See RFC 4254, section 5.3 +const msgChannelEOF = 96 + +type channelEOFMsg struct { + PeersID uint32 `sshtype:"96"` +} + +// See RFC 4254, section 4 +const msgGlobalRequest = 80 + +type globalRequestMsg struct { + Type string `sshtype:"80"` + WantReply bool + Data []byte `ssh:"rest"` +} + +// See RFC 4254, section 4 +const msgRequestSuccess = 81 + +type globalRequestSuccessMsg struct { + Data []byte `ssh:"rest" sshtype:"81"` +} + +// See RFC 4254, section 4 +const msgRequestFailure = 82 + +type globalRequestFailureMsg struct { + Data []byte `ssh:"rest" sshtype:"82"` +} + +// See RFC 4254, section 5.2 +const msgChannelWindowAdjust = 93 + +type windowAdjustMsg struct { + PeersID uint32 `sshtype:"93"` + AdditionalBytes uint32 +} + +// See RFC 4252, section 7 +const msgUserAuthPubKeyOk = 60 + +type userAuthPubKeyOkMsg struct { + Algo string `sshtype:"60"` + PubKey []byte +} + +// See RFC 4462, section 3 +const msgUserAuthGSSAPIResponse = 60 + +type userAuthGSSAPIResponse struct { + SupportMech []byte `sshtype:"60"` +} + +const msgUserAuthGSSAPIToken = 61 + +type userAuthGSSAPIToken struct { + Token []byte `sshtype:"61"` +} + +const msgUserAuthGSSAPIMIC = 66 + +type userAuthGSSAPIMIC struct { + MIC []byte `sshtype:"66"` +} + +// See RFC 4462, section 3.9 +const msgUserAuthGSSAPIErrTok = 64 + +type userAuthGSSAPIErrTok struct { + ErrorToken []byte `sshtype:"64"` +} + +// See RFC 4462, section 3.8 +const msgUserAuthGSSAPIError = 65 + +type userAuthGSSAPIError struct { + MajorStatus uint32 `sshtype:"65"` + MinorStatus uint32 + Message string + LanguageTag string +} + +// Transport layer OpenSSH extension. See [PROTOCOL], section 1.9 +const msgPing = 192 + +type pingMsg struct { + Data string `sshtype:"192"` +} + +// Transport layer OpenSSH extension. See [PROTOCOL], section 1.9 +const msgPong = 193 + +type pongMsg struct { + Data string `sshtype:"193"` +} + +// typeTags returns the possible type bytes for the given reflect.Type, which +// should be a struct. The possible values are separated by a '|' character. +func typeTags(structType reflect.Type) (tags []byte) { + tagStr := structType.Field(0).Tag.Get("sshtype") + + for _, tag := range strings.Split(tagStr, "|") { + i, err := strconv.Atoi(tag) + if err == nil { + tags = append(tags, byte(i)) + } + } + + return tags +} + +func fieldError(t reflect.Type, field int, problem string) error { + if problem != "" { + problem = ": " + problem + } + return fmt.Errorf("ssh: unmarshal error for field %s of type %s%s", t.Field(field).Name, t.Name(), problem) +} + +var errShortRead = errors.New("ssh: short read") + +// Unmarshal parses data in SSH wire format into a structure. The out +// argument should be a pointer to struct. If the first member of the +// struct has the "sshtype" tag set to a '|'-separated set of numbers +// in decimal, the packet must start with one of those numbers. In +// case of error, Unmarshal returns a ParseError or +// UnexpectedMessageError. +func Unmarshal(data []byte, out interface{}) error { + v := reflect.ValueOf(out).Elem() + structType := v.Type() + expectedTypes := typeTags(structType) + + var expectedType byte + if len(expectedTypes) > 0 { + expectedType = expectedTypes[0] + } + + if len(data) == 0 { + return parseError(expectedType) + } + + if len(expectedTypes) > 0 { + goodType := false + for _, e := range expectedTypes { + if e > 0 && data[0] == e { + goodType = true + break + } + } + if !goodType { + return fmt.Errorf("ssh: unexpected message type %d (expected one of %v)", data[0], expectedTypes) + } + data = data[1:] + } + + var ok bool + for i := 0; i < v.NumField(); i++ { + field := v.Field(i) + t := field.Type() + switch t.Kind() { + case reflect.Bool: + if len(data) < 1 { + return errShortRead + } + field.SetBool(data[0] != 0) + data = data[1:] + case reflect.Array: + if t.Elem().Kind() != reflect.Uint8 { + return fieldError(structType, i, "array of unsupported type") + } + if len(data) < t.Len() { + return errShortRead + } + for j, n := 0, t.Len(); j < n; j++ { + field.Index(j).Set(reflect.ValueOf(data[j])) + } + data = data[t.Len():] + case reflect.Uint64: + var u64 uint64 + if u64, data, ok = parseUint64(data); !ok { + return errShortRead + } + field.SetUint(u64) + case reflect.Uint32: + var u32 uint32 + if u32, data, ok = parseUint32(data); !ok { + return errShortRead + } + field.SetUint(uint64(u32)) + case reflect.Uint8: + if len(data) < 1 { + return errShortRead + } + field.SetUint(uint64(data[0])) + data = data[1:] + case reflect.String: + var s []byte + if s, data, ok = parseString(data); !ok { + return fieldError(structType, i, "") + } + field.SetString(string(s)) + case reflect.Slice: + switch t.Elem().Kind() { + case reflect.Uint8: + if structType.Field(i).Tag.Get("ssh") == "rest" { + field.Set(reflect.ValueOf(data)) + data = nil + } else { + var s []byte + if s, data, ok = parseString(data); !ok { + return errShortRead + } + field.Set(reflect.ValueOf(s)) + } + case reflect.String: + var nl []string + if nl, data, ok = parseNameList(data); !ok { + return errShortRead + } + field.Set(reflect.ValueOf(nl)) + default: + return fieldError(structType, i, "slice of unsupported type") + } + case reflect.Ptr: + if t == bigIntType { + var n *big.Int + if n, data, ok = parseInt(data); !ok { + return errShortRead + } + field.Set(reflect.ValueOf(n)) + } else { + return fieldError(structType, i, "pointer to unsupported type") + } + default: + return fieldError(structType, i, fmt.Sprintf("unsupported type: %v", t)) + } + } + + if len(data) != 0 { + return parseError(expectedType) + } + + return nil +} + +// Marshal serializes the message in msg to SSH wire format. The msg +// argument should be a struct or pointer to struct. If the first +// member has the "sshtype" tag set to a number in decimal, that +// number is prepended to the result. If the last of member has the +// "ssh" tag set to "rest", its contents are appended to the output. +func Marshal(msg interface{}) []byte { + out := make([]byte, 0, 64) + return marshalStruct(out, msg) +} + +func marshalStruct(out []byte, msg interface{}) []byte { + v := reflect.Indirect(reflect.ValueOf(msg)) + msgTypes := typeTags(v.Type()) + if len(msgTypes) > 0 { + out = append(out, msgTypes[0]) + } + + for i, n := 0, v.NumField(); i < n; i++ { + field := v.Field(i) + switch t := field.Type(); t.Kind() { + case reflect.Bool: + var v uint8 + if field.Bool() { + v = 1 + } + out = append(out, v) + case reflect.Array: + if t.Elem().Kind() != reflect.Uint8 { + panic(fmt.Sprintf("array of non-uint8 in field %d: %T", i, field.Interface())) + } + for j, l := 0, t.Len(); j < l; j++ { + out = append(out, uint8(field.Index(j).Uint())) + } + case reflect.Uint32: + out = appendU32(out, uint32(field.Uint())) + case reflect.Uint64: + out = appendU64(out, uint64(field.Uint())) + case reflect.Uint8: + out = append(out, uint8(field.Uint())) + case reflect.String: + s := field.String() + out = appendInt(out, len(s)) + out = append(out, s...) + case reflect.Slice: + switch t.Elem().Kind() { + case reflect.Uint8: + if v.Type().Field(i).Tag.Get("ssh") != "rest" { + out = appendInt(out, field.Len()) + } + out = append(out, field.Bytes()...) + case reflect.String: + offset := len(out) + out = appendU32(out, 0) + if n := field.Len(); n > 0 { + for j := 0; j < n; j++ { + f := field.Index(j) + if j != 0 { + out = append(out, ',') + } + out = append(out, f.String()...) + } + // overwrite length value + binary.BigEndian.PutUint32(out[offset:], uint32(len(out)-offset-4)) + } + default: + panic(fmt.Sprintf("slice of unknown type in field %d: %T", i, field.Interface())) + } + case reflect.Ptr: + if t == bigIntType { + var n *big.Int + nValue := reflect.ValueOf(&n) + nValue.Elem().Set(field) + needed := intLength(n) + oldLength := len(out) + + if cap(out)-len(out) < needed { + newOut := make([]byte, len(out), 2*(len(out)+needed)) + copy(newOut, out) + out = newOut + } + out = out[:oldLength+needed] + marshalInt(out[oldLength:], n) + } else { + panic(fmt.Sprintf("pointer to unknown type in field %d: %T", i, field.Interface())) + } + } + } + + return out +} + +var bigOne = big.NewInt(1) + +func parseString(in []byte) (out, rest []byte, ok bool) { + if len(in) < 4 { + return + } + length := binary.BigEndian.Uint32(in) + in = in[4:] + if uint32(len(in)) < length { + return + } + out = in[:length] + rest = in[length:] + ok = true + return +} + +var ( + comma = []byte{','} + emptyNameList = []string{} +) + +func parseNameList(in []byte) (out []string, rest []byte, ok bool) { + contents, rest, ok := parseString(in) + if !ok { + return + } + if len(contents) == 0 { + out = emptyNameList + return + } + parts := bytes.Split(contents, comma) + out = make([]string, len(parts)) + for i, part := range parts { + out[i] = string(part) + } + return +} + +func parseInt(in []byte) (out *big.Int, rest []byte, ok bool) { + contents, rest, ok := parseString(in) + if !ok { + return + } + out = new(big.Int) + + if len(contents) > 0 && contents[0]&0x80 == 0x80 { + // This is a negative number + notBytes := make([]byte, len(contents)) + for i := range notBytes { + notBytes[i] = ^contents[i] + } + out.SetBytes(notBytes) + out.Add(out, bigOne) + out.Neg(out) + } else { + // Positive number + out.SetBytes(contents) + } + ok = true + return +} + +func parseUint32(in []byte) (uint32, []byte, bool) { + if len(in) < 4 { + return 0, nil, false + } + return binary.BigEndian.Uint32(in), in[4:], true +} + +func parseUint64(in []byte) (uint64, []byte, bool) { + if len(in) < 8 { + return 0, nil, false + } + return binary.BigEndian.Uint64(in), in[8:], true +} + +func intLength(n *big.Int) int { + length := 4 /* length bytes */ + if n.Sign() < 0 { + nMinus1 := new(big.Int).Neg(n) + nMinus1.Sub(nMinus1, bigOne) + bitLen := nMinus1.BitLen() + if bitLen%8 == 0 { + // The number will need 0xff padding + length++ + } + length += (bitLen + 7) / 8 + } else if n.Sign() == 0 { + // A zero is the zero length string + } else { + bitLen := n.BitLen() + if bitLen%8 == 0 { + // The number will need 0x00 padding + length++ + } + length += (bitLen + 7) / 8 + } + + return length +} + +func marshalUint32(to []byte, n uint32) []byte { + binary.BigEndian.PutUint32(to, n) + return to[4:] +} + +func marshalUint64(to []byte, n uint64) []byte { + binary.BigEndian.PutUint64(to, n) + return to[8:] +} + +func marshalInt(to []byte, n *big.Int) []byte { + lengthBytes := to + to = to[4:] + length := 0 + + if n.Sign() < 0 { + // A negative number has to be converted to two's-complement + // form. So we'll subtract 1 and invert. If the + // most-significant-bit isn't set then we'll need to pad the + // beginning with 0xff in order to keep the number negative. + nMinus1 := new(big.Int).Neg(n) + nMinus1.Sub(nMinus1, bigOne) + bytes := nMinus1.Bytes() + for i := range bytes { + bytes[i] ^= 0xff + } + if len(bytes) == 0 || bytes[0]&0x80 == 0 { + to[0] = 0xff + to = to[1:] + length++ + } + nBytes := copy(to, bytes) + to = to[nBytes:] + length += nBytes + } else if n.Sign() == 0 { + // A zero is the zero length string + } else { + bytes := n.Bytes() + if len(bytes) > 0 && bytes[0]&0x80 != 0 { + // We'll have to pad this with a 0x00 in order to + // stop it looking like a negative number. + to[0] = 0 + to = to[1:] + length++ + } + nBytes := copy(to, bytes) + to = to[nBytes:] + length += nBytes + } + + lengthBytes[0] = byte(length >> 24) + lengthBytes[1] = byte(length >> 16) + lengthBytes[2] = byte(length >> 8) + lengthBytes[3] = byte(length) + return to +} + +func writeInt(w io.Writer, n *big.Int) { + length := intLength(n) + buf := make([]byte, length) + marshalInt(buf, n) + w.Write(buf) +} + +func writeString(w io.Writer, s []byte) { + var lengthBytes [4]byte + lengthBytes[0] = byte(len(s) >> 24) + lengthBytes[1] = byte(len(s) >> 16) + lengthBytes[2] = byte(len(s) >> 8) + lengthBytes[3] = byte(len(s)) + w.Write(lengthBytes[:]) + w.Write(s) +} + +func stringLength(n int) int { + return 4 + n +} + +func marshalString(to []byte, s []byte) []byte { + to[0] = byte(len(s) >> 24) + to[1] = byte(len(s) >> 16) + to[2] = byte(len(s) >> 8) + to[3] = byte(len(s)) + to = to[4:] + copy(to, s) + return to[len(s):] +} + +var bigIntType = reflect.TypeOf((*big.Int)(nil)) + +// Decode a packet into its corresponding message. +func decode(packet []byte) (interface{}, error) { + var msg interface{} + switch packet[0] { + case msgDisconnect: + msg = new(disconnectMsg) + case msgServiceRequest: + msg = new(serviceRequestMsg) + case msgServiceAccept: + msg = new(serviceAcceptMsg) + case msgExtInfo: + msg = new(extInfoMsg) + case msgKexInit: + msg = new(kexInitMsg) + case msgKexDHInit: + msg = new(kexDHInitMsg) + case msgKexDHReply: + msg = new(kexDHReplyMsg) + case msgUserAuthRequest: + msg = new(userAuthRequestMsg) + case msgUserAuthSuccess: + return new(userAuthSuccessMsg), nil + case msgUserAuthFailure: + msg = new(userAuthFailureMsg) + case msgUserAuthPubKeyOk: + msg = new(userAuthPubKeyOkMsg) + case msgGlobalRequest: + msg = new(globalRequestMsg) + case msgRequestSuccess: + msg = new(globalRequestSuccessMsg) + case msgRequestFailure: + msg = new(globalRequestFailureMsg) + case msgChannelOpen: + msg = new(channelOpenMsg) + case msgChannelData: + msg = new(channelDataMsg) + case msgChannelOpenConfirm: + msg = new(channelOpenConfirmMsg) + case msgChannelOpenFailure: + msg = new(channelOpenFailureMsg) + case msgChannelWindowAdjust: + msg = new(windowAdjustMsg) + case msgChannelEOF: + msg = new(channelEOFMsg) + case msgChannelClose: + msg = new(channelCloseMsg) + case msgChannelRequest: + msg = new(channelRequestMsg) + case msgChannelSuccess: + msg = new(channelRequestSuccessMsg) + case msgChannelFailure: + msg = new(channelRequestFailureMsg) + case msgUserAuthGSSAPIToken: + msg = new(userAuthGSSAPIToken) + case msgUserAuthGSSAPIMIC: + msg = new(userAuthGSSAPIMIC) + case msgUserAuthGSSAPIErrTok: + msg = new(userAuthGSSAPIErrTok) + case msgUserAuthGSSAPIError: + msg = new(userAuthGSSAPIError) + default: + return nil, unexpectedMessageError(0, packet[0]) + } + if err := Unmarshal(packet, msg); err != nil { + return nil, err + } + return msg, nil +} + +var packetTypeNames = map[byte]string{ + msgDisconnect: "disconnectMsg", + msgServiceRequest: "serviceRequestMsg", + msgServiceAccept: "serviceAcceptMsg", + msgExtInfo: "extInfoMsg", + msgKexInit: "kexInitMsg", + msgKexDHInit: "kexDHInitMsg", + msgKexDHReply: "kexDHReplyMsg", + msgUserAuthRequest: "userAuthRequestMsg", + msgUserAuthSuccess: "userAuthSuccessMsg", + msgUserAuthFailure: "userAuthFailureMsg", + msgUserAuthPubKeyOk: "userAuthPubKeyOkMsg", + msgGlobalRequest: "globalRequestMsg", + msgRequestSuccess: "globalRequestSuccessMsg", + msgRequestFailure: "globalRequestFailureMsg", + msgChannelOpen: "channelOpenMsg", + msgChannelData: "channelDataMsg", + msgChannelOpenConfirm: "channelOpenConfirmMsg", + msgChannelOpenFailure: "channelOpenFailureMsg", + msgChannelWindowAdjust: "windowAdjustMsg", + msgChannelEOF: "channelEOFMsg", + msgChannelClose: "channelCloseMsg", + msgChannelRequest: "channelRequestMsg", + msgChannelSuccess: "channelRequestSuccessMsg", + msgChannelFailure: "channelRequestFailureMsg", +} diff --git a/tempfork/sshtest/ssh/messages_test.go b/tempfork/sshtest/ssh/messages_test.go new file mode 100644 index 000000000..e79076412 --- /dev/null +++ b/tempfork/sshtest/ssh/messages_test.go @@ -0,0 +1,288 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "bytes" + "math/big" + "math/rand" + "reflect" + "testing" + "testing/quick" +) + +var intLengthTests = []struct { + val, length int +}{ + {0, 4 + 0}, + {1, 4 + 1}, + {127, 4 + 1}, + {128, 4 + 2}, + {-1, 4 + 1}, +} + +func TestIntLength(t *testing.T) { + for _, test := range intLengthTests { + v := new(big.Int).SetInt64(int64(test.val)) + length := intLength(v) + if length != test.length { + t.Errorf("For %d, got length %d but expected %d", test.val, length, test.length) + } + } +} + +type msgAllTypes struct { + Bool bool `sshtype:"21"` + Array [16]byte + Uint64 uint64 + Uint32 uint32 + Uint8 uint8 + String string + Strings []string + Bytes []byte + Int *big.Int + Rest []byte `ssh:"rest"` +} + +func (t *msgAllTypes) Generate(rand *rand.Rand, size int) reflect.Value { + m := &msgAllTypes{} + m.Bool = rand.Intn(2) == 1 + randomBytes(m.Array[:], rand) + m.Uint64 = uint64(rand.Int63n(1<<63 - 1)) + m.Uint32 = uint32(rand.Intn((1 << 31) - 1)) + m.Uint8 = uint8(rand.Intn(1 << 8)) + m.String = string(m.Array[:]) + m.Strings = randomNameList(rand) + m.Bytes = m.Array[:] + m.Int = randomInt(rand) + m.Rest = m.Array[:] + return reflect.ValueOf(m) +} + +func TestMarshalUnmarshal(t *testing.T) { + rand := rand.New(rand.NewSource(0)) + iface := &msgAllTypes{} + ty := reflect.ValueOf(iface).Type() + + n := 100 + if testing.Short() { + n = 5 + } + for j := 0; j < n; j++ { + v, ok := quick.Value(ty, rand) + if !ok { + t.Errorf("failed to create value") + break + } + + m1 := v.Elem().Interface() + m2 := iface + + marshaled := Marshal(m1) + if err := Unmarshal(marshaled, m2); err != nil { + t.Errorf("Unmarshal %#v: %s", m1, err) + break + } + + if !reflect.DeepEqual(v.Interface(), m2) { + t.Errorf("got: %#v\nwant:%#v\n%x", m2, m1, marshaled) + break + } + } +} + +func TestUnmarshalEmptyPacket(t *testing.T) { + var b []byte + var m channelRequestSuccessMsg + if err := Unmarshal(b, &m); err == nil { + t.Fatalf("unmarshal of empty slice succeeded") + } +} + +func TestUnmarshalUnexpectedPacket(t *testing.T) { + type S struct { + I uint32 `sshtype:"43"` + S string + B bool + } + + s := S{11, "hello", true} + packet := Marshal(s) + packet[0] = 42 + roundtrip := S{} + err := Unmarshal(packet, &roundtrip) + if err == nil { + t.Fatal("expected error, not nil") + } +} + +func TestMarshalPtr(t *testing.T) { + s := struct { + S string + }{"hello"} + + m1 := Marshal(s) + m2 := Marshal(&s) + if !bytes.Equal(m1, m2) { + t.Errorf("got %q, want %q for marshaled pointer", m2, m1) + } +} + +func TestBareMarshalUnmarshal(t *testing.T) { + type S struct { + I uint32 + S string + B bool + } + + s := S{42, "hello", true} + packet := Marshal(s) + roundtrip := S{} + Unmarshal(packet, &roundtrip) + + if !reflect.DeepEqual(s, roundtrip) { + t.Errorf("got %#v, want %#v", roundtrip, s) + } +} + +func TestBareMarshal(t *testing.T) { + type S2 struct { + I uint32 + } + s := S2{42} + packet := Marshal(s) + i, rest, ok := parseUint32(packet) + if len(rest) > 0 || !ok { + t.Errorf("parseInt(%q): parse error", packet) + } + if i != s.I { + t.Errorf("got %d, want %d", i, s.I) + } +} + +func TestUnmarshalShortKexInitPacket(t *testing.T) { + // This used to panic. + // Issue 11348 + packet := []byte{0x14, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0xff, 0xff, 0xff, 0xff} + kim := &kexInitMsg{} + if err := Unmarshal(packet, kim); err == nil { + t.Error("truncated packet unmarshaled without error") + } +} + +func TestMarshalMultiTag(t *testing.T) { + var res struct { + A uint32 `sshtype:"1|2"` + } + + good1 := struct { + A uint32 `sshtype:"1"` + }{ + 1, + } + good2 := struct { + A uint32 `sshtype:"2"` + }{ + 1, + } + + if e := Unmarshal(Marshal(good1), &res); e != nil { + t.Errorf("error unmarshaling multipart tag: %v", e) + } + + if e := Unmarshal(Marshal(good2), &res); e != nil { + t.Errorf("error unmarshaling multipart tag: %v", e) + } + + bad1 := struct { + A uint32 `sshtype:"3"` + }{ + 1, + } + if e := Unmarshal(Marshal(bad1), &res); e == nil { + t.Errorf("bad struct unmarshaled without error") + } +} + +func randomBytes(out []byte, rand *rand.Rand) { + for i := 0; i < len(out); i++ { + out[i] = byte(rand.Int31()) + } +} + +func randomNameList(rand *rand.Rand) []string { + ret := make([]string, rand.Int31()&15) + for i := range ret { + s := make([]byte, 1+(rand.Int31()&15)) + for j := range s { + s[j] = 'a' + uint8(rand.Int31()&15) + } + ret[i] = string(s) + } + return ret +} + +func randomInt(rand *rand.Rand) *big.Int { + return new(big.Int).SetInt64(int64(int32(rand.Uint32()))) +} + +func (*kexInitMsg) Generate(rand *rand.Rand, size int) reflect.Value { + ki := &kexInitMsg{} + randomBytes(ki.Cookie[:], rand) + ki.KexAlgos = randomNameList(rand) + ki.ServerHostKeyAlgos = randomNameList(rand) + ki.CiphersClientServer = randomNameList(rand) + ki.CiphersServerClient = randomNameList(rand) + ki.MACsClientServer = randomNameList(rand) + ki.MACsServerClient = randomNameList(rand) + ki.CompressionClientServer = randomNameList(rand) + ki.CompressionServerClient = randomNameList(rand) + ki.LanguagesClientServer = randomNameList(rand) + ki.LanguagesServerClient = randomNameList(rand) + if rand.Int31()&1 == 1 { + ki.FirstKexFollows = true + } + return reflect.ValueOf(ki) +} + +func (*kexDHInitMsg) Generate(rand *rand.Rand, size int) reflect.Value { + dhi := &kexDHInitMsg{} + dhi.X = randomInt(rand) + return reflect.ValueOf(dhi) +} + +var ( + _kexInitMsg = new(kexInitMsg).Generate(rand.New(rand.NewSource(0)), 10).Elem().Interface() + _kexDHInitMsg = new(kexDHInitMsg).Generate(rand.New(rand.NewSource(0)), 10).Elem().Interface() + + _kexInit = Marshal(_kexInitMsg) + _kexDHInit = Marshal(_kexDHInitMsg) +) + +func BenchmarkMarshalKexInitMsg(b *testing.B) { + for i := 0; i < b.N; i++ { + Marshal(_kexInitMsg) + } +} + +func BenchmarkUnmarshalKexInitMsg(b *testing.B) { + m := new(kexInitMsg) + for i := 0; i < b.N; i++ { + Unmarshal(_kexInit, m) + } +} + +func BenchmarkMarshalKexDHInitMsg(b *testing.B) { + for i := 0; i < b.N; i++ { + Marshal(_kexDHInitMsg) + } +} + +func BenchmarkUnmarshalKexDHInitMsg(b *testing.B) { + m := new(kexDHInitMsg) + for i := 0; i < b.N; i++ { + Unmarshal(_kexDHInit, m) + } +} diff --git a/tempfork/sshtest/ssh/mux.go b/tempfork/sshtest/ssh/mux.go new file mode 100644 index 000000000..d2d24c635 --- /dev/null +++ b/tempfork/sshtest/ssh/mux.go @@ -0,0 +1,357 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "encoding/binary" + "fmt" + "io" + "log" + "sync" + "sync/atomic" +) + +// debugMux, if set, causes messages in the connection protocol to be +// logged. +const debugMux = false + +// chanList is a thread safe channel list. +type chanList struct { + // protects concurrent access to chans + sync.Mutex + + // chans are indexed by the local id of the channel, which the + // other side should send in the PeersId field. + chans []*channel + + // This is a debugging aid: it offsets all IDs by this + // amount. This helps distinguish otherwise identical + // server/client muxes + offset uint32 +} + +// Assigns a channel ID to the given channel. +func (c *chanList) add(ch *channel) uint32 { + c.Lock() + defer c.Unlock() + for i := range c.chans { + if c.chans[i] == nil { + c.chans[i] = ch + return uint32(i) + c.offset + } + } + c.chans = append(c.chans, ch) + return uint32(len(c.chans)-1) + c.offset +} + +// getChan returns the channel for the given ID. +func (c *chanList) getChan(id uint32) *channel { + id -= c.offset + + c.Lock() + defer c.Unlock() + if id < uint32(len(c.chans)) { + return c.chans[id] + } + return nil +} + +func (c *chanList) remove(id uint32) { + id -= c.offset + c.Lock() + if id < uint32(len(c.chans)) { + c.chans[id] = nil + } + c.Unlock() +} + +// dropAll forgets all channels it knows, returning them in a slice. +func (c *chanList) dropAll() []*channel { + c.Lock() + defer c.Unlock() + var r []*channel + + for _, ch := range c.chans { + if ch == nil { + continue + } + r = append(r, ch) + } + c.chans = nil + return r +} + +// mux represents the state for the SSH connection protocol, which +// multiplexes many channels onto a single packet transport. +type mux struct { + conn packetConn + chanList chanList + + incomingChannels chan NewChannel + + globalSentMu sync.Mutex + globalResponses chan interface{} + incomingRequests chan *Request + + errCond *sync.Cond + err error +} + +// When debugging, each new chanList instantiation has a different +// offset. +var globalOff uint32 + +func (m *mux) Wait() error { + m.errCond.L.Lock() + defer m.errCond.L.Unlock() + for m.err == nil { + m.errCond.Wait() + } + return m.err +} + +// newMux returns a mux that runs over the given connection. +func newMux(p packetConn) *mux { + m := &mux{ + conn: p, + incomingChannels: make(chan NewChannel, chanSize), + globalResponses: make(chan interface{}, 1), + incomingRequests: make(chan *Request, chanSize), + errCond: newCond(), + } + if debugMux { + m.chanList.offset = atomic.AddUint32(&globalOff, 1) + } + + go m.loop() + return m +} + +func (m *mux) sendMessage(msg interface{}) error { + p := Marshal(msg) + if debugMux { + log.Printf("send global(%d): %#v", m.chanList.offset, msg) + } + return m.conn.writePacket(p) +} + +func (m *mux) SendRequest(name string, wantReply bool, payload []byte) (bool, []byte, error) { + if wantReply { + m.globalSentMu.Lock() + defer m.globalSentMu.Unlock() + } + + if err := m.sendMessage(globalRequestMsg{ + Type: name, + WantReply: wantReply, + Data: payload, + }); err != nil { + return false, nil, err + } + + if !wantReply { + return false, nil, nil + } + + msg, ok := <-m.globalResponses + if !ok { + return false, nil, io.EOF + } + switch msg := msg.(type) { + case *globalRequestFailureMsg: + return false, msg.Data, nil + case *globalRequestSuccessMsg: + return true, msg.Data, nil + default: + return false, nil, fmt.Errorf("ssh: unexpected response to request: %#v", msg) + } +} + +// ackRequest must be called after processing a global request that +// has WantReply set. +func (m *mux) ackRequest(ok bool, data []byte) error { + if ok { + return m.sendMessage(globalRequestSuccessMsg{Data: data}) + } + return m.sendMessage(globalRequestFailureMsg{Data: data}) +} + +func (m *mux) Close() error { + return m.conn.Close() +} + +// loop runs the connection machine. It will process packets until an +// error is encountered. To synchronize on loop exit, use mux.Wait. +func (m *mux) loop() { + var err error + for err == nil { + err = m.onePacket() + } + + for _, ch := range m.chanList.dropAll() { + ch.close() + } + + close(m.incomingChannels) + close(m.incomingRequests) + close(m.globalResponses) + + m.conn.Close() + + m.errCond.L.Lock() + m.err = err + m.errCond.Broadcast() + m.errCond.L.Unlock() + + if debugMux { + log.Println("loop exit", err) + } +} + +// onePacket reads and processes one packet. +func (m *mux) onePacket() error { + packet, err := m.conn.readPacket() + if err != nil { + return err + } + + if debugMux { + if packet[0] == msgChannelData || packet[0] == msgChannelExtendedData { + log.Printf("decoding(%d): data packet - %d bytes", m.chanList.offset, len(packet)) + } else { + p, _ := decode(packet) + log.Printf("decoding(%d): %d %#v - %d bytes", m.chanList.offset, packet[0], p, len(packet)) + } + } + + switch packet[0] { + case msgChannelOpen: + return m.handleChannelOpen(packet) + case msgGlobalRequest, msgRequestSuccess, msgRequestFailure: + return m.handleGlobalPacket(packet) + case msgPing: + var msg pingMsg + if err := Unmarshal(packet, &msg); err != nil { + return fmt.Errorf("failed to unmarshal ping@openssh.com message: %w", err) + } + return m.sendMessage(pongMsg(msg)) + } + + // assume a channel packet. + if len(packet) < 5 { + return parseError(packet[0]) + } + id := binary.BigEndian.Uint32(packet[1:]) + ch := m.chanList.getChan(id) + if ch == nil { + return m.handleUnknownChannelPacket(id, packet) + } + + return ch.handlePacket(packet) +} + +func (m *mux) handleGlobalPacket(packet []byte) error { + msg, err := decode(packet) + if err != nil { + return err + } + + switch msg := msg.(type) { + case *globalRequestMsg: + m.incomingRequests <- &Request{ + Type: msg.Type, + WantReply: msg.WantReply, + Payload: msg.Data, + mux: m, + } + case *globalRequestSuccessMsg, *globalRequestFailureMsg: + m.globalResponses <- msg + default: + panic(fmt.Sprintf("not a global message %#v", msg)) + } + + return nil +} + +// handleChannelOpen schedules a channel to be Accept()ed. +func (m *mux) handleChannelOpen(packet []byte) error { + var msg channelOpenMsg + if err := Unmarshal(packet, &msg); err != nil { + return err + } + + if msg.MaxPacketSize < minPacketLength || msg.MaxPacketSize > 1<<31 { + failMsg := channelOpenFailureMsg{ + PeersID: msg.PeersID, + Reason: ConnectionFailed, + Message: "invalid request", + Language: "en_US.UTF-8", + } + return m.sendMessage(failMsg) + } + + c := m.newChannel(msg.ChanType, channelInbound, msg.TypeSpecificData) + c.remoteId = msg.PeersID + c.maxRemotePayload = msg.MaxPacketSize + c.remoteWin.add(msg.PeersWindow) + m.incomingChannels <- c + return nil +} + +func (m *mux) OpenChannel(chanType string, extra []byte) (Channel, <-chan *Request, error) { + ch, err := m.openChannel(chanType, extra) + if err != nil { + return nil, nil, err + } + + return ch, ch.incomingRequests, nil +} + +func (m *mux) openChannel(chanType string, extra []byte) (*channel, error) { + ch := m.newChannel(chanType, channelOutbound, extra) + + ch.maxIncomingPayload = channelMaxPacket + + open := channelOpenMsg{ + ChanType: chanType, + PeersWindow: ch.myWindow, + MaxPacketSize: ch.maxIncomingPayload, + TypeSpecificData: extra, + PeersID: ch.localId, + } + if err := m.sendMessage(open); err != nil { + return nil, err + } + + switch msg := (<-ch.msg).(type) { + case *channelOpenConfirmMsg: + return ch, nil + case *channelOpenFailureMsg: + return nil, &OpenChannelError{msg.Reason, msg.Message} + default: + return nil, fmt.Errorf("ssh: unexpected packet in response to channel open: %T", msg) + } +} + +func (m *mux) handleUnknownChannelPacket(id uint32, packet []byte) error { + msg, err := decode(packet) + if err != nil { + return err + } + + switch msg := msg.(type) { + // RFC 4254 section 5.4 says unrecognized channel requests should + // receive a failure response. + case *channelRequestMsg: + if msg.WantReply { + return m.sendMessage(channelRequestFailureMsg{ + PeersID: msg.PeersID, + }) + } + return nil + default: + return fmt.Errorf("ssh: invalid channel %d", id) + } +} diff --git a/tempfork/sshtest/ssh/mux_test.go b/tempfork/sshtest/ssh/mux_test.go new file mode 100644 index 000000000..21f0ac3e3 --- /dev/null +++ b/tempfork/sshtest/ssh/mux_test.go @@ -0,0 +1,839 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "errors" + "fmt" + "io" + "sync" + "testing" +) + +func muxPair() (*mux, *mux) { + a, b := memPipe() + + s := newMux(a) + c := newMux(b) + + return s, c +} + +// Returns both ends of a channel, and the mux for the 2nd +// channel. +func channelPair(t *testing.T) (*channel, *channel, *mux) { + c, s := muxPair() + + res := make(chan *channel, 1) + go func() { + newCh, ok := <-s.incomingChannels + if !ok { + t.Error("no incoming channel") + close(res) + return + } + if newCh.ChannelType() != "chan" { + t.Errorf("got type %q want chan", newCh.ChannelType()) + newCh.Reject(Prohibited, fmt.Sprintf("got type %q want chan", newCh.ChannelType())) + close(res) + return + } + ch, _, err := newCh.Accept() + if err != nil { + t.Errorf("accept: %v", err) + close(res) + return + } + res <- ch.(*channel) + }() + + ch, err := c.openChannel("chan", nil) + if err != nil { + t.Fatalf("OpenChannel: %v", err) + } + w := <-res + if w == nil { + t.Fatal("unable to get write channel") + } + + return w, ch, c +} + +// Test that stderr and stdout can be addressed from different +// goroutines. This is intended for use with the race detector. +func TestMuxChannelExtendedThreadSafety(t *testing.T) { + writer, reader, mux := channelPair(t) + defer writer.Close() + defer reader.Close() + defer mux.Close() + + var wr, rd sync.WaitGroup + magic := "hello world" + + wr.Add(2) + go func() { + io.WriteString(writer, magic) + wr.Done() + }() + go func() { + io.WriteString(writer.Stderr(), magic) + wr.Done() + }() + + rd.Add(2) + go func() { + c, err := io.ReadAll(reader) + if string(c) != magic { + t.Errorf("stdout read got %q, want %q (error %s)", c, magic, err) + } + rd.Done() + }() + go func() { + c, err := io.ReadAll(reader.Stderr()) + if string(c) != magic { + t.Errorf("stderr read got %q, want %q (error %s)", c, magic, err) + } + rd.Done() + }() + + wr.Wait() + writer.CloseWrite() + rd.Wait() +} + +func TestMuxReadWrite(t *testing.T) { + s, c, mux := channelPair(t) + defer s.Close() + defer c.Close() + defer mux.Close() + + magic := "hello world" + magicExt := "hello stderr" + var wg sync.WaitGroup + t.Cleanup(wg.Wait) + wg.Add(1) + go func() { + defer wg.Done() + _, err := s.Write([]byte(magic)) + if err != nil { + t.Errorf("Write: %v", err) + return + } + _, err = s.Extended(1).Write([]byte(magicExt)) + if err != nil { + t.Errorf("Write: %v", err) + return + } + }() + + var buf [1024]byte + n, err := c.Read(buf[:]) + if err != nil { + t.Fatalf("server Read: %v", err) + } + got := string(buf[:n]) + if got != magic { + t.Fatalf("server: got %q want %q", got, magic) + } + + n, err = c.Extended(1).Read(buf[:]) + if err != nil { + t.Fatalf("server Read: %v", err) + } + + got = string(buf[:n]) + if got != magicExt { + t.Fatalf("server: got %q want %q", got, magic) + } +} + +func TestMuxChannelOverflow(t *testing.T) { + reader, writer, mux := channelPair(t) + defer reader.Close() + defer writer.Close() + defer mux.Close() + + var wg sync.WaitGroup + t.Cleanup(wg.Wait) + wg.Add(1) + go func() { + defer wg.Done() + if _, err := writer.Write(make([]byte, channelWindowSize)); err != nil { + t.Errorf("could not fill window: %v", err) + } + writer.Write(make([]byte, 1)) + }() + writer.remoteWin.waitWriterBlocked() + + // Send 1 byte. + packet := make([]byte, 1+4+4+1) + packet[0] = msgChannelData + marshalUint32(packet[1:], writer.remoteId) + marshalUint32(packet[5:], uint32(1)) + packet[9] = 42 + + if err := writer.mux.conn.writePacket(packet); err != nil { + t.Errorf("could not send packet") + } + if _, err := reader.SendRequest("hello", true, nil); err == nil { + t.Errorf("SendRequest succeeded.") + } +} + +func TestMuxChannelReadUnblock(t *testing.T) { + reader, writer, mux := channelPair(t) + defer reader.Close() + defer writer.Close() + defer mux.Close() + + var wg sync.WaitGroup + t.Cleanup(wg.Wait) + wg.Add(1) + go func() { + defer wg.Done() + if _, err := writer.Write(make([]byte, channelWindowSize)); err != nil { + t.Errorf("could not fill window: %v", err) + } + if _, err := writer.Write(make([]byte, 1)); err != nil { + t.Errorf("Write: %v", err) + } + writer.Close() + }() + + writer.remoteWin.waitWriterBlocked() + + buf := make([]byte, 32768) + for { + _, err := reader.Read(buf) + if err == io.EOF { + break + } + if err != nil { + t.Fatalf("Read: %v", err) + } + } +} + +func TestMuxChannelCloseWriteUnblock(t *testing.T) { + reader, writer, mux := channelPair(t) + defer reader.Close() + defer writer.Close() + defer mux.Close() + + var wg sync.WaitGroup + t.Cleanup(wg.Wait) + wg.Add(1) + go func() { + defer wg.Done() + if _, err := writer.Write(make([]byte, channelWindowSize)); err != nil { + t.Errorf("could not fill window: %v", err) + } + if _, err := writer.Write(make([]byte, 1)); err != io.EOF { + t.Errorf("got %v, want EOF for unblock write", err) + } + }() + + writer.remoteWin.waitWriterBlocked() + reader.Close() +} + +func TestMuxConnectionCloseWriteUnblock(t *testing.T) { + reader, writer, mux := channelPair(t) + defer reader.Close() + defer writer.Close() + defer mux.Close() + + var wg sync.WaitGroup + t.Cleanup(wg.Wait) + wg.Add(1) + go func() { + defer wg.Done() + if _, err := writer.Write(make([]byte, channelWindowSize)); err != nil { + t.Errorf("could not fill window: %v", err) + } + if _, err := writer.Write(make([]byte, 1)); err != io.EOF { + t.Errorf("got %v, want EOF for unblock write", err) + } + }() + + writer.remoteWin.waitWriterBlocked() + mux.Close() +} + +func TestMuxReject(t *testing.T) { + client, server := muxPair() + defer server.Close() + defer client.Close() + + var wg sync.WaitGroup + t.Cleanup(wg.Wait) + wg.Add(1) + go func() { + defer wg.Done() + + ch, ok := <-server.incomingChannels + if !ok { + t.Error("cannot accept channel") + return + } + if ch.ChannelType() != "ch" || string(ch.ExtraData()) != "extra" { + t.Errorf("unexpected channel: %q, %q", ch.ChannelType(), ch.ExtraData()) + ch.Reject(RejectionReason(UnknownChannelType), UnknownChannelType.String()) + return + } + ch.Reject(RejectionReason(42), "message") + }() + + ch, err := client.openChannel("ch", []byte("extra")) + if ch != nil { + t.Fatal("openChannel not rejected") + } + + ocf, ok := err.(*OpenChannelError) + if !ok { + t.Errorf("got %#v want *OpenChannelError", err) + } else if ocf.Reason != 42 || ocf.Message != "message" { + t.Errorf("got %#v, want {Reason: 42, Message: %q}", ocf, "message") + } + + want := "ssh: rejected: unknown reason 42 (message)" + if err.Error() != want { + t.Errorf("got %q, want %q", err.Error(), want) + } +} + +func TestMuxChannelRequest(t *testing.T) { + client, server, mux := channelPair(t) + defer server.Close() + defer client.Close() + defer mux.Close() + + var received int + var wg sync.WaitGroup + t.Cleanup(wg.Wait) + wg.Add(1) + go func() { + for r := range server.incomingRequests { + received++ + r.Reply(r.Type == "yes", nil) + } + wg.Done() + }() + _, err := client.SendRequest("yes", false, nil) + if err != nil { + t.Fatalf("SendRequest: %v", err) + } + ok, err := client.SendRequest("yes", true, nil) + if err != nil { + t.Fatalf("SendRequest: %v", err) + } + + if !ok { + t.Errorf("SendRequest(yes): %v", ok) + + } + + ok, err = client.SendRequest("no", true, nil) + if err != nil { + t.Fatalf("SendRequest: %v", err) + } + if ok { + t.Errorf("SendRequest(no): %v", ok) + } + + client.Close() + wg.Wait() + + if received != 3 { + t.Errorf("got %d requests, want %d", received, 3) + } +} + +func TestMuxUnknownChannelRequests(t *testing.T) { + clientPipe, serverPipe := memPipe() + client := newMux(clientPipe) + defer serverPipe.Close() + defer client.Close() + + kDone := make(chan error, 1) + go func() { + // Ignore unknown channel messages that don't want a reply. + err := serverPipe.writePacket(Marshal(channelRequestMsg{ + PeersID: 1, + Request: "keepalive@openssh.com", + WantReply: false, + RequestSpecificData: []byte{}, + })) + if err != nil { + kDone <- fmt.Errorf("send: %w", err) + return + } + + // Send a keepalive, which should get a channel failure message + // in response. + err = serverPipe.writePacket(Marshal(channelRequestMsg{ + PeersID: 2, + Request: "keepalive@openssh.com", + WantReply: true, + RequestSpecificData: []byte{}, + })) + if err != nil { + kDone <- fmt.Errorf("send: %w", err) + return + } + + packet, err := serverPipe.readPacket() + if err != nil { + kDone <- fmt.Errorf("read packet: %w", err) + return + } + decoded, err := decode(packet) + if err != nil { + kDone <- fmt.Errorf("decode failed: %w", err) + return + } + + switch msg := decoded.(type) { + case *channelRequestFailureMsg: + if msg.PeersID != 2 { + kDone <- fmt.Errorf("received response to wrong message: %v", msg) + return + + } + default: + kDone <- fmt.Errorf("unexpected channel message: %v", msg) + return + } + + kDone <- nil + + // Receive and respond to the keepalive to confirm the mux is + // still processing requests. + packet, err = serverPipe.readPacket() + if err != nil { + kDone <- fmt.Errorf("read packet: %w", err) + return + } + if packet[0] != msgGlobalRequest { + kDone <- errors.New("expected global request") + return + } + + err = serverPipe.writePacket(Marshal(globalRequestFailureMsg{ + Data: []byte{}, + })) + if err != nil { + kDone <- fmt.Errorf("failed to send failure msg: %w", err) + return + } + + close(kDone) + }() + + // Wait for the server to send the keepalive message and receive back a + // response. + if err := <-kDone; err != nil { + t.Fatal(err) + } + + // Confirm client hasn't closed. + if _, _, err := client.SendRequest("keepalive@golang.org", true, nil); err != nil { + t.Fatalf("failed to send keepalive: %v", err) + } + + // Wait for the server to shut down. + if err := <-kDone; err != nil { + t.Fatal(err) + } +} + +func TestMuxClosedChannel(t *testing.T) { + clientPipe, serverPipe := memPipe() + client := newMux(clientPipe) + defer serverPipe.Close() + defer client.Close() + + kDone := make(chan error, 1) + go func() { + // Open the channel. + packet, err := serverPipe.readPacket() + if err != nil { + kDone <- fmt.Errorf("read packet: %w", err) + return + } + if packet[0] != msgChannelOpen { + kDone <- errors.New("expected chan open") + return + } + + var openMsg channelOpenMsg + if err := Unmarshal(packet, &openMsg); err != nil { + kDone <- fmt.Errorf("unmarshal: %w", err) + return + } + + // Send back the opened channel confirmation. + err = serverPipe.writePacket(Marshal(channelOpenConfirmMsg{ + PeersID: openMsg.PeersID, + MyID: 0, + MyWindow: 0, + MaxPacketSize: channelMaxPacket, + })) + if err != nil { + kDone <- fmt.Errorf("send: %w", err) + return + } + + // Close the channel. + err = serverPipe.writePacket(Marshal(channelCloseMsg{ + PeersID: openMsg.PeersID, + })) + if err != nil { + kDone <- fmt.Errorf("send: %w", err) + return + } + + // Send a keepalive message on the channel we just closed. + err = serverPipe.writePacket(Marshal(channelRequestMsg{ + PeersID: openMsg.PeersID, + Request: "keepalive@openssh.com", + WantReply: true, + RequestSpecificData: []byte{}, + })) + if err != nil { + kDone <- fmt.Errorf("send: %w", err) + return + } + + // Receive the channel closed response. + packet, err = serverPipe.readPacket() + if err != nil { + kDone <- fmt.Errorf("read packet: %w", err) + return + } + if packet[0] != msgChannelClose { + kDone <- errors.New("expected channel close") + return + } + + // Receive the keepalive response failure. + packet, err = serverPipe.readPacket() + if err != nil { + kDone <- fmt.Errorf("read packet: %w", err) + return + } + if packet[0] != msgChannelFailure { + kDone <- errors.New("expected channel failure") + return + } + kDone <- nil + + // Receive and respond to the keepalive to confirm the mux is + // still processing requests. + packet, err = serverPipe.readPacket() + if err != nil { + kDone <- fmt.Errorf("read packet: %w", err) + return + } + if packet[0] != msgGlobalRequest { + kDone <- errors.New("expected global request") + return + } + + err = serverPipe.writePacket(Marshal(globalRequestFailureMsg{ + Data: []byte{}, + })) + if err != nil { + kDone <- fmt.Errorf("failed to send failure msg: %w", err) + return + } + + close(kDone) + }() + + // Open a channel. + ch, err := client.openChannel("chan", nil) + if err != nil { + t.Fatalf("OpenChannel: %v", err) + } + defer ch.Close() + + // Wait for the server to close the channel and send the keepalive. + <-kDone + + // Make sure the channel closed. + if _, ok := <-ch.incomingRequests; ok { + t.Fatalf("channel not closed") + } + + // Confirm client hasn't closed + if _, _, err := client.SendRequest("keepalive@golang.org", true, nil); err != nil { + t.Fatalf("failed to send keepalive: %v", err) + } + + // Wait for the server to shut down. + <-kDone +} + +func TestMuxGlobalRequest(t *testing.T) { + var sawPeek bool + var wg sync.WaitGroup + defer func() { + wg.Wait() + if !sawPeek { + t.Errorf("never saw 'peek' request") + } + }() + + clientMux, serverMux := muxPair() + defer serverMux.Close() + defer clientMux.Close() + + wg.Add(1) + go func() { + defer wg.Done() + for r := range serverMux.incomingRequests { + sawPeek = sawPeek || r.Type == "peek" + if r.WantReply { + err := r.Reply(r.Type == "yes", + append([]byte(r.Type), r.Payload...)) + if err != nil { + t.Errorf("AckRequest: %v", err) + } + } + } + }() + + _, _, err := clientMux.SendRequest("peek", false, nil) + if err != nil { + t.Errorf("SendRequest: %v", err) + } + + ok, data, err := clientMux.SendRequest("yes", true, []byte("a")) + if !ok || string(data) != "yesa" || err != nil { + t.Errorf("SendRequest(\"yes\", true, \"a\"): %v %v %v", + ok, data, err) + } + if ok, data, err := clientMux.SendRequest("yes", true, []byte("a")); !ok || string(data) != "yesa" || err != nil { + t.Errorf("SendRequest(\"yes\", true, \"a\"): %v %v %v", + ok, data, err) + } + + if ok, data, err := clientMux.SendRequest("no", true, []byte("a")); ok || string(data) != "noa" || err != nil { + t.Errorf("SendRequest(\"no\", true, \"a\"): %v %v %v", + ok, data, err) + } +} + +func TestMuxGlobalRequestUnblock(t *testing.T) { + clientMux, serverMux := muxPair() + defer serverMux.Close() + defer clientMux.Close() + + result := make(chan error, 1) + go func() { + _, _, err := clientMux.SendRequest("hello", true, nil) + result <- err + }() + + <-serverMux.incomingRequests + serverMux.conn.Close() + err := <-result + + if err != io.EOF { + t.Errorf("want EOF, got %v", io.EOF) + } +} + +func TestMuxChannelRequestUnblock(t *testing.T) { + a, b, connB := channelPair(t) + defer a.Close() + defer b.Close() + defer connB.Close() + + result := make(chan error, 1) + go func() { + _, err := a.SendRequest("hello", true, nil) + result <- err + }() + + <-b.incomingRequests + connB.conn.Close() + err := <-result + + if err != io.EOF { + t.Errorf("want EOF, got %v", err) + } +} + +func TestMuxCloseChannel(t *testing.T) { + r, w, mux := channelPair(t) + defer mux.Close() + defer r.Close() + defer w.Close() + + result := make(chan error, 1) + go func() { + var b [1024]byte + _, err := r.Read(b[:]) + result <- err + }() + if err := w.Close(); err != nil { + t.Errorf("w.Close: %v", err) + } + + if _, err := w.Write([]byte("hello")); err != io.EOF { + t.Errorf("got err %v, want io.EOF after Close", err) + } + + if err := <-result; err != io.EOF { + t.Errorf("got %v (%T), want io.EOF", err, err) + } +} + +func TestMuxCloseWriteChannel(t *testing.T) { + r, w, mux := channelPair(t) + defer mux.Close() + + result := make(chan error, 1) + go func() { + var b [1024]byte + _, err := r.Read(b[:]) + result <- err + }() + if err := w.CloseWrite(); err != nil { + t.Errorf("w.CloseWrite: %v", err) + } + + if _, err := w.Write([]byte("hello")); err != io.EOF { + t.Errorf("got err %v, want io.EOF after CloseWrite", err) + } + + if err := <-result; err != io.EOF { + t.Errorf("got %v (%T), want io.EOF", err, err) + } +} + +func TestMuxInvalidRecord(t *testing.T) { + a, b := muxPair() + defer a.Close() + defer b.Close() + + packet := make([]byte, 1+4+4+1) + packet[0] = msgChannelData + marshalUint32(packet[1:], 29348723 /* invalid channel id */) + marshalUint32(packet[5:], 1) + packet[9] = 42 + + a.conn.writePacket(packet) + go a.SendRequest("hello", false, nil) + // 'a' wrote an invalid packet, so 'b' has exited. + req, ok := <-b.incomingRequests + if ok { + t.Errorf("got request %#v after receiving invalid packet", req) + } +} + +func TestZeroWindowAdjust(t *testing.T) { + a, b, mux := channelPair(t) + defer a.Close() + defer b.Close() + defer mux.Close() + + go func() { + io.WriteString(a, "hello") + // bogus adjust. + a.sendMessage(windowAdjustMsg{}) + io.WriteString(a, "world") + a.Close() + }() + + want := "helloworld" + c, _ := io.ReadAll(b) + if string(c) != want { + t.Errorf("got %q want %q", c, want) + } +} + +func TestMuxMaxPacketSize(t *testing.T) { + a, b, mux := channelPair(t) + defer a.Close() + defer b.Close() + defer mux.Close() + + large := make([]byte, a.maxRemotePayload+1) + packet := make([]byte, 1+4+4+1+len(large)) + packet[0] = msgChannelData + marshalUint32(packet[1:], a.remoteId) + marshalUint32(packet[5:], uint32(len(large))) + packet[9] = 42 + + if err := a.mux.conn.writePacket(packet); err != nil { + t.Errorf("could not send packet") + } + + var wg sync.WaitGroup + t.Cleanup(wg.Wait) + wg.Add(1) + go func() { + a.SendRequest("hello", false, nil) + wg.Done() + }() + + _, ok := <-b.incomingRequests + if ok { + t.Errorf("connection still alive after receiving large packet.") + } +} + +func TestMuxChannelWindowDeferredUpdates(t *testing.T) { + s, c, mux := channelPair(t) + cTransport := mux.conn.(*memTransport) + defer s.Close() + defer c.Close() + defer mux.Close() + + var wg sync.WaitGroup + t.Cleanup(wg.Wait) + + data := make([]byte, 1024) + + wg.Add(1) + go func() { + defer wg.Done() + _, err := s.Write(data) + if err != nil { + t.Errorf("Write: %v", err) + return + } + }() + cWritesInit := cTransport.getWriteCount() + buf := make([]byte, 1) + for i := 0; i < len(data); i++ { + n, err := c.Read(buf) + if n != len(buf) || err != nil { + t.Fatalf("Read: %v, %v", n, err) + } + } + cWrites := cTransport.getWriteCount() - cWritesInit + // reading 1 KiB should not cause any window updates to be sent, but allow + // for some unexpected writes + if cWrites > 30 { + t.Fatalf("reading 1 KiB from channel caused %v writes", cWrites) + } +} + +// Don't ship code with debug=true. +func TestDebug(t *testing.T) { + if debugMux { + t.Error("mux debug switched on") + } + if debugHandshake { + t.Error("handshake debug switched on") + } + if debugTransport { + t.Error("transport debug switched on") + } +} diff --git a/tempfork/sshtest/ssh/server.go b/tempfork/sshtest/ssh/server.go new file mode 100644 index 000000000..1839ddc6a --- /dev/null +++ b/tempfork/sshtest/ssh/server.go @@ -0,0 +1,933 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "bytes" + "errors" + "fmt" + "io" + "net" + "strings" +) + +// The Permissions type holds fine-grained permissions that are +// specific to a user or a specific authentication method for a user. +// The Permissions value for a successful authentication attempt is +// available in ServerConn, so it can be used to pass information from +// the user-authentication phase to the application layer. +type Permissions struct { + // CriticalOptions indicate restrictions to the default + // permissions, and are typically used in conjunction with + // user certificates. The standard for SSH certificates + // defines "force-command" (only allow the given command to + // execute) and "source-address" (only allow connections from + // the given address). The SSH package currently only enforces + // the "source-address" critical option. It is up to server + // implementations to enforce other critical options, such as + // "force-command", by checking them after the SSH handshake + // is successful. In general, SSH servers should reject + // connections that specify critical options that are unknown + // or not supported. + CriticalOptions map[string]string + + // Extensions are extra functionality that the server may + // offer on authenticated connections. Lack of support for an + // extension does not preclude authenticating a user. Common + // extensions are "permit-agent-forwarding", + // "permit-X11-forwarding". The Go SSH library currently does + // not act on any extension, and it is up to server + // implementations to honor them. Extensions can be used to + // pass data from the authentication callbacks to the server + // application layer. + Extensions map[string]string +} + +type GSSAPIWithMICConfig struct { + // AllowLogin, must be set, is called when gssapi-with-mic + // authentication is selected (RFC 4462 section 3). The srcName is from the + // results of the GSS-API authentication. The format is username@DOMAIN. + // GSSAPI just guarantees to the server who the user is, but not if they can log in, and with what permissions. + // This callback is called after the user identity is established with GSSAPI to decide if the user can login with + // which permissions. If the user is allowed to login, it should return a nil error. + AllowLogin func(conn ConnMetadata, srcName string) (*Permissions, error) + + // Server must be set. It's the implementation + // of the GSSAPIServer interface. See GSSAPIServer interface for details. + Server GSSAPIServer +} + +// SendAuthBanner implements [ServerPreAuthConn]. +func (s *connection) SendAuthBanner(msg string) error { + return s.transport.writePacket(Marshal(&userAuthBannerMsg{ + Message: msg, + })) +} + +func (*connection) unexportedMethodForFutureProofing() {} + +// ServerPreAuthConn is the interface available on an incoming server +// connection before authentication has completed. +type ServerPreAuthConn interface { + unexportedMethodForFutureProofing() // permits growing ServerPreAuthConn safely later, ala testing.TB + + ConnMetadata + + // SendAuthBanner sends a banner message to the client. + // It returns an error once the authentication phase has ended. + SendAuthBanner(string) error +} + +// ServerConfig holds server specific configuration data. +type ServerConfig struct { + // Config contains configuration shared between client and server. + Config + + // PublicKeyAuthAlgorithms specifies the supported client public key + // authentication algorithms. Note that this should not include certificate + // types since those use the underlying algorithm. This list is sent to the + // client if it supports the server-sig-algs extension. Order is irrelevant. + // If unspecified then a default set of algorithms is used. + PublicKeyAuthAlgorithms []string + + hostKeys []Signer + + // NoClientAuth is true if clients are allowed to connect without + // authenticating. + // To determine NoClientAuth at runtime, set NoClientAuth to true + // and the optional NoClientAuthCallback to a non-nil value. + NoClientAuth bool + + // NoClientAuthCallback, if non-nil, is called when a user + // attempts to authenticate with auth method "none". + // NoClientAuth must also be set to true for this be used, or + // this func is unused. + NoClientAuthCallback func(ConnMetadata) (*Permissions, error) + + // MaxAuthTries specifies the maximum number of authentication attempts + // permitted per connection. If set to a negative number, the number of + // attempts are unlimited. If set to zero, the number of attempts are limited + // to 6. + MaxAuthTries int + + // PasswordCallback, if non-nil, is called when a user + // attempts to authenticate using a password. + PasswordCallback func(conn ConnMetadata, password []byte) (*Permissions, error) + + // PublicKeyCallback, if non-nil, is called when a client + // offers a public key for authentication. It must return a nil error + // if the given public key can be used to authenticate the + // given user. For example, see CertChecker.Authenticate. A + // call to this function does not guarantee that the key + // offered is in fact used to authenticate. To record any data + // depending on the public key, store it inside a + // Permissions.Extensions entry. + PublicKeyCallback func(conn ConnMetadata, key PublicKey) (*Permissions, error) + + // KeyboardInteractiveCallback, if non-nil, is called when + // keyboard-interactive authentication is selected (RFC + // 4256). The client object's Challenge function should be + // used to query the user. The callback may offer multiple + // Challenge rounds. To avoid information leaks, the client + // should be presented a challenge even if the user is + // unknown. + KeyboardInteractiveCallback func(conn ConnMetadata, client KeyboardInteractiveChallenge) (*Permissions, error) + + // AuthLogCallback, if non-nil, is called to log all authentication + // attempts. + AuthLogCallback func(conn ConnMetadata, method string, err error) + + // PreAuthConnCallback, if non-nil, is called upon receiving a new connection + // before any authentication has started. The provided ServerPreAuthConn + // can be used at any time before authentication is complete, including + // after this callback has returned. + PreAuthConnCallback func(ServerPreAuthConn) + + // ServerVersion is the version identification string to announce in + // the public handshake. + // If empty, a reasonable default is used. + // Note that RFC 4253 section 4.2 requires that this string start with + // "SSH-2.0-". + ServerVersion string + + // BannerCallback, if present, is called and the return string is sent to + // the client after key exchange completed but before authentication. + BannerCallback func(conn ConnMetadata) string + + // GSSAPIWithMICConfig includes gssapi server and callback, which if both non-nil, is used + // when gssapi-with-mic authentication is selected (RFC 4462 section 3). + GSSAPIWithMICConfig *GSSAPIWithMICConfig +} + +// AddHostKey adds a private key as a host key. If an existing host +// key exists with the same public key format, it is replaced. Each server +// config must have at least one host key. +func (s *ServerConfig) AddHostKey(key Signer) { + for i, k := range s.hostKeys { + if k.PublicKey().Type() == key.PublicKey().Type() { + s.hostKeys[i] = key + return + } + } + + s.hostKeys = append(s.hostKeys, key) +} + +// cachedPubKey contains the results of querying whether a public key is +// acceptable for a user. This is a FIFO cache. +type cachedPubKey struct { + user string + pubKeyData []byte + result error + perms *Permissions +} + +// maxCachedPubKeys is the number of cache entries we store. +// +// Due to consistent misuse of the PublicKeyCallback API, we have reduced this +// to 1, such that the only key in the cache is the most recently seen one. This +// forces the behavior that the last call to PublicKeyCallback will always be +// with the key that is used for authentication. +const maxCachedPubKeys = 1 + +// pubKeyCache caches tests for public keys. Since SSH clients +// will query whether a public key is acceptable before attempting to +// authenticate with it, we end up with duplicate queries for public +// key validity. The cache only applies to a single ServerConn. +type pubKeyCache struct { + keys []cachedPubKey +} + +// get returns the result for a given user/algo/key tuple. +func (c *pubKeyCache) get(user string, pubKeyData []byte) (cachedPubKey, bool) { + for _, k := range c.keys { + if k.user == user && bytes.Equal(k.pubKeyData, pubKeyData) { + return k, true + } + } + return cachedPubKey{}, false +} + +// add adds the given tuple to the cache. +func (c *pubKeyCache) add(candidate cachedPubKey) { + if len(c.keys) >= maxCachedPubKeys { + c.keys = c.keys[1:] + } + c.keys = append(c.keys, candidate) +} + +// ServerConn is an authenticated SSH connection, as seen from the +// server +type ServerConn struct { + Conn + + // If the succeeding authentication callback returned a + // non-nil Permissions pointer, it is stored here. + Permissions *Permissions +} + +// NewServerConn starts a new SSH server with c as the underlying +// transport. It starts with a handshake and, if the handshake is +// unsuccessful, it closes the connection and returns an error. The +// Request and NewChannel channels must be serviced, or the connection +// will hang. +// +// The returned error may be of type *ServerAuthError for +// authentication errors. +func NewServerConn(c net.Conn, config *ServerConfig) (*ServerConn, <-chan NewChannel, <-chan *Request, error) { + fullConf := *config + fullConf.SetDefaults() + if fullConf.MaxAuthTries == 0 { + fullConf.MaxAuthTries = 6 + } + if len(fullConf.PublicKeyAuthAlgorithms) == 0 { + fullConf.PublicKeyAuthAlgorithms = supportedPubKeyAuthAlgos + } else { + for _, algo := range fullConf.PublicKeyAuthAlgorithms { + if !contains(supportedPubKeyAuthAlgos, algo) { + c.Close() + return nil, nil, nil, fmt.Errorf("ssh: unsupported public key authentication algorithm %s", algo) + } + } + } + // Check if the config contains any unsupported key exchanges + for _, kex := range fullConf.KeyExchanges { + if _, ok := serverForbiddenKexAlgos[kex]; ok { + c.Close() + return nil, nil, nil, fmt.Errorf("ssh: unsupported key exchange %s for server", kex) + } + } + + s := &connection{ + sshConn: sshConn{conn: c}, + } + perms, err := s.serverHandshake(&fullConf) + if err != nil { + c.Close() + return nil, nil, nil, err + } + return &ServerConn{s, perms}, s.mux.incomingChannels, s.mux.incomingRequests, nil +} + +// signAndMarshal signs the data with the appropriate algorithm, +// and serializes the result in SSH wire format. algo is the negotiate +// algorithm and may be a certificate type. +func signAndMarshal(k AlgorithmSigner, rand io.Reader, data []byte, algo string) ([]byte, error) { + sig, err := k.SignWithAlgorithm(rand, data, underlyingAlgo(algo)) + if err != nil { + return nil, err + } + + return Marshal(sig), nil +} + +// handshake performs key exchange and user authentication. +func (s *connection) serverHandshake(config *ServerConfig) (*Permissions, error) { + if len(config.hostKeys) == 0 { + return nil, errors.New("ssh: server has no host keys") + } + + if !config.NoClientAuth && config.PasswordCallback == nil && config.PublicKeyCallback == nil && + config.KeyboardInteractiveCallback == nil && (config.GSSAPIWithMICConfig == nil || + config.GSSAPIWithMICConfig.AllowLogin == nil || config.GSSAPIWithMICConfig.Server == nil) { + return nil, errors.New("ssh: no authentication methods configured but NoClientAuth is also false") + } + + if config.ServerVersion != "" { + s.serverVersion = []byte(config.ServerVersion) + } else { + s.serverVersion = []byte(packageVersion) + } + var err error + s.clientVersion, err = exchangeVersions(s.sshConn.conn, s.serverVersion) + if err != nil { + return nil, err + } + + tr := newTransport(s.sshConn.conn, config.Rand, false /* not client */) + s.transport = newServerTransport(tr, s.clientVersion, s.serverVersion, config) + + if err := s.transport.waitSession(); err != nil { + return nil, err + } + + // We just did the key change, so the session ID is established. + s.sessionID = s.transport.getSessionID() + + var packet []byte + if packet, err = s.transport.readPacket(); err != nil { + return nil, err + } + + var serviceRequest serviceRequestMsg + if err = Unmarshal(packet, &serviceRequest); err != nil { + return nil, err + } + if serviceRequest.Service != serviceUserAuth { + return nil, errors.New("ssh: requested service '" + serviceRequest.Service + "' before authenticating") + } + serviceAccept := serviceAcceptMsg{ + Service: serviceUserAuth, + } + if err := s.transport.writePacket(Marshal(&serviceAccept)); err != nil { + return nil, err + } + + perms, err := s.serverAuthenticate(config) + if err != nil { + return nil, err + } + s.mux = newMux(s.transport) + return perms, err +} + +func checkSourceAddress(addr net.Addr, sourceAddrs string) error { + if addr == nil { + return errors.New("ssh: no address known for client, but source-address match required") + } + + tcpAddr, ok := addr.(*net.TCPAddr) + if !ok { + return fmt.Errorf("ssh: remote address %v is not an TCP address when checking source-address match", addr) + } + + for _, sourceAddr := range strings.Split(sourceAddrs, ",") { + if allowedIP := net.ParseIP(sourceAddr); allowedIP != nil { + if allowedIP.Equal(tcpAddr.IP) { + return nil + } + } else { + _, ipNet, err := net.ParseCIDR(sourceAddr) + if err != nil { + return fmt.Errorf("ssh: error parsing source-address restriction %q: %v", sourceAddr, err) + } + + if ipNet.Contains(tcpAddr.IP) { + return nil + } + } + } + + return fmt.Errorf("ssh: remote address %v is not allowed because of source-address restriction", addr) +} + +func gssExchangeToken(gssapiConfig *GSSAPIWithMICConfig, token []byte, s *connection, + sessionID []byte, userAuthReq userAuthRequestMsg) (authErr error, perms *Permissions, err error) { + gssAPIServer := gssapiConfig.Server + defer gssAPIServer.DeleteSecContext() + var srcName string + for { + var ( + outToken []byte + needContinue bool + ) + outToken, srcName, needContinue, err = gssAPIServer.AcceptSecContext(token) + if err != nil { + return err, nil, nil + } + if len(outToken) != 0 { + if err := s.transport.writePacket(Marshal(&userAuthGSSAPIToken{ + Token: outToken, + })); err != nil { + return nil, nil, err + } + } + if !needContinue { + break + } + packet, err := s.transport.readPacket() + if err != nil { + return nil, nil, err + } + userAuthGSSAPITokenReq := &userAuthGSSAPIToken{} + if err := Unmarshal(packet, userAuthGSSAPITokenReq); err != nil { + return nil, nil, err + } + token = userAuthGSSAPITokenReq.Token + } + packet, err := s.transport.readPacket() + if err != nil { + return nil, nil, err + } + userAuthGSSAPIMICReq := &userAuthGSSAPIMIC{} + if err := Unmarshal(packet, userAuthGSSAPIMICReq); err != nil { + return nil, nil, err + } + mic := buildMIC(string(sessionID), userAuthReq.User, userAuthReq.Service, userAuthReq.Method) + if err := gssAPIServer.VerifyMIC(mic, userAuthGSSAPIMICReq.MIC); err != nil { + return err, nil, nil + } + perms, authErr = gssapiConfig.AllowLogin(s, srcName) + return authErr, perms, nil +} + +// isAlgoCompatible checks if the signature format is compatible with the +// selected algorithm taking into account edge cases that occur with old +// clients. +func isAlgoCompatible(algo, sigFormat string) bool { + // Compatibility for old clients. + // + // For certificate authentication with OpenSSH 7.2-7.7 signature format can + // be rsa-sha2-256 or rsa-sha2-512 for the algorithm + // ssh-rsa-cert-v01@openssh.com. + // + // With gpg-agent < 2.2.6 the algorithm can be rsa-sha2-256 or rsa-sha2-512 + // for signature format ssh-rsa. + if isRSA(algo) && isRSA(sigFormat) { + return true + } + // Standard case: the underlying algorithm must match the signature format. + return underlyingAlgo(algo) == sigFormat +} + +// ServerAuthError represents server authentication errors and is +// sometimes returned by NewServerConn. It appends any authentication +// errors that may occur, and is returned if all of the authentication +// methods provided by the user failed to authenticate. +type ServerAuthError struct { + // Errors contains authentication errors returned by the authentication + // callback methods. The first entry is typically ErrNoAuth. + Errors []error +} + +func (l ServerAuthError) Error() string { + var errs []string + for _, err := range l.Errors { + errs = append(errs, err.Error()) + } + return "[" + strings.Join(errs, ", ") + "]" +} + +// ServerAuthCallbacks defines server-side authentication callbacks. +type ServerAuthCallbacks struct { + // PasswordCallback behaves like [ServerConfig.PasswordCallback]. + PasswordCallback func(conn ConnMetadata, password []byte) (*Permissions, error) + + // PublicKeyCallback behaves like [ServerConfig.PublicKeyCallback]. + PublicKeyCallback func(conn ConnMetadata, key PublicKey) (*Permissions, error) + + // KeyboardInteractiveCallback behaves like [ServerConfig.KeyboardInteractiveCallback]. + KeyboardInteractiveCallback func(conn ConnMetadata, client KeyboardInteractiveChallenge) (*Permissions, error) + + // GSSAPIWithMICConfig behaves like [ServerConfig.GSSAPIWithMICConfig]. + GSSAPIWithMICConfig *GSSAPIWithMICConfig +} + +// PartialSuccessError can be returned by any of the [ServerConfig] +// authentication callbacks to indicate to the client that authentication has +// partially succeeded, but further steps are required. +type PartialSuccessError struct { + // Next defines the authentication callbacks to apply to further steps. The + // available methods communicated to the client are based on the non-nil + // ServerAuthCallbacks fields. + Next ServerAuthCallbacks +} + +func (p *PartialSuccessError) Error() string { + return "ssh: authenticated with partial success" +} + +// ErrNoAuth is the error value returned if no +// authentication method has been passed yet. This happens as a normal +// part of the authentication loop, since the client first tries +// 'none' authentication to discover available methods. +// It is returned in ServerAuthError.Errors from NewServerConn. +var ErrNoAuth = errors.New("ssh: no auth passed yet") + +// BannerError is an error that can be returned by authentication handlers in +// ServerConfig to send a banner message to the client. +type BannerError struct { + Err error + Message string +} + +func (b *BannerError) Unwrap() error { + return b.Err +} + +func (b *BannerError) Error() string { + if b.Err == nil { + return b.Message + } + return b.Err.Error() +} + +func (s *connection) serverAuthenticate(config *ServerConfig) (*Permissions, error) { + if config.PreAuthConnCallback != nil { + config.PreAuthConnCallback(s) + } + + sessionID := s.transport.getSessionID() + var cache pubKeyCache + var perms *Permissions + + authFailures := 0 + noneAuthCount := 0 + var authErrs []error + var calledBannerCallback bool + partialSuccessReturned := false + // Set the initial authentication callbacks from the config. They can be + // changed if a PartialSuccessError is returned. + authConfig := ServerAuthCallbacks{ + PasswordCallback: config.PasswordCallback, + PublicKeyCallback: config.PublicKeyCallback, + KeyboardInteractiveCallback: config.KeyboardInteractiveCallback, + GSSAPIWithMICConfig: config.GSSAPIWithMICConfig, + } + +userAuthLoop: + for { + if authFailures >= config.MaxAuthTries && config.MaxAuthTries > 0 { + discMsg := &disconnectMsg{ + Reason: 2, + Message: "too many authentication failures", + } + + if err := s.transport.writePacket(Marshal(discMsg)); err != nil { + return nil, err + } + authErrs = append(authErrs, discMsg) + return nil, &ServerAuthError{Errors: authErrs} + } + + var userAuthReq userAuthRequestMsg + if packet, err := s.transport.readPacket(); err != nil { + if err == io.EOF { + return nil, &ServerAuthError{Errors: authErrs} + } + return nil, err + } else if err = Unmarshal(packet, &userAuthReq); err != nil { + return nil, err + } + + if userAuthReq.Service != serviceSSH { + return nil, errors.New("ssh: client attempted to negotiate for unknown service: " + userAuthReq.Service) + } + + if s.user != userAuthReq.User && partialSuccessReturned { + return nil, fmt.Errorf("ssh: client changed the user after a partial success authentication, previous user %q, current user %q", + s.user, userAuthReq.User) + } + + s.user = userAuthReq.User + + if !calledBannerCallback && config.BannerCallback != nil { + calledBannerCallback = true + if msg := config.BannerCallback(s); msg != "" { + if err := s.SendAuthBanner(msg); err != nil { + return nil, err + } + } + } + + perms = nil + authErr := ErrNoAuth + + switch userAuthReq.Method { + case "none": + noneAuthCount++ + // We don't allow none authentication after a partial success + // response. + if config.NoClientAuth && !partialSuccessReturned { + if config.NoClientAuthCallback != nil { + perms, authErr = config.NoClientAuthCallback(s) + } else { + authErr = nil + } + } + case "password": + if authConfig.PasswordCallback == nil { + authErr = errors.New("ssh: password auth not configured") + break + } + payload := userAuthReq.Payload + if len(payload) < 1 || payload[0] != 0 { + return nil, parseError(msgUserAuthRequest) + } + payload = payload[1:] + password, payload, ok := parseString(payload) + if !ok || len(payload) > 0 { + return nil, parseError(msgUserAuthRequest) + } + + perms, authErr = authConfig.PasswordCallback(s, password) + case "keyboard-interactive": + if authConfig.KeyboardInteractiveCallback == nil { + authErr = errors.New("ssh: keyboard-interactive auth not configured") + break + } + + prompter := &sshClientKeyboardInteractive{s} + perms, authErr = authConfig.KeyboardInteractiveCallback(s, prompter.Challenge) + case "publickey": + if authConfig.PublicKeyCallback == nil { + authErr = errors.New("ssh: publickey auth not configured") + break + } + payload := userAuthReq.Payload + if len(payload) < 1 { + return nil, parseError(msgUserAuthRequest) + } + isQuery := payload[0] == 0 + payload = payload[1:] + algoBytes, payload, ok := parseString(payload) + if !ok { + return nil, parseError(msgUserAuthRequest) + } + algo := string(algoBytes) + if !contains(config.PublicKeyAuthAlgorithms, underlyingAlgo(algo)) { + authErr = fmt.Errorf("ssh: algorithm %q not accepted", algo) + break + } + + pubKeyData, payload, ok := parseString(payload) + if !ok { + return nil, parseError(msgUserAuthRequest) + } + + pubKey, err := ParsePublicKey(pubKeyData) + if err != nil { + return nil, err + } + + candidate, ok := cache.get(s.user, pubKeyData) + if !ok { + candidate.user = s.user + candidate.pubKeyData = pubKeyData + candidate.perms, candidate.result = authConfig.PublicKeyCallback(s, pubKey) + _, isPartialSuccessError := candidate.result.(*PartialSuccessError) + + if (candidate.result == nil || isPartialSuccessError) && + candidate.perms != nil && + candidate.perms.CriticalOptions != nil && + candidate.perms.CriticalOptions[sourceAddressCriticalOption] != "" { + if err := checkSourceAddress( + s.RemoteAddr(), + candidate.perms.CriticalOptions[sourceAddressCriticalOption]); err != nil { + candidate.result = err + } + } + cache.add(candidate) + } + + if isQuery { + // The client can query if the given public key + // would be okay. + + if len(payload) > 0 { + return nil, parseError(msgUserAuthRequest) + } + _, isPartialSuccessError := candidate.result.(*PartialSuccessError) + if candidate.result == nil || isPartialSuccessError { + okMsg := userAuthPubKeyOkMsg{ + Algo: algo, + PubKey: pubKeyData, + } + if err = s.transport.writePacket(Marshal(&okMsg)); err != nil { + return nil, err + } + continue userAuthLoop + } + authErr = candidate.result + } else { + sig, payload, ok := parseSignature(payload) + if !ok || len(payload) > 0 { + return nil, parseError(msgUserAuthRequest) + } + // Ensure the declared public key algo is compatible with the + // decoded one. This check will ensure we don't accept e.g. + // ssh-rsa-cert-v01@openssh.com algorithm with ssh-rsa public + // key type. The algorithm and public key type must be + // consistent: both must be certificate algorithms, or neither. + if !contains(algorithmsForKeyFormat(pubKey.Type()), algo) { + authErr = fmt.Errorf("ssh: public key type %q not compatible with selected algorithm %q", + pubKey.Type(), algo) + break + } + // Ensure the public key algo and signature algo + // are supported. Compare the private key + // algorithm name that corresponds to algo with + // sig.Format. This is usually the same, but + // for certs, the names differ. + if !contains(config.PublicKeyAuthAlgorithms, sig.Format) { + authErr = fmt.Errorf("ssh: algorithm %q not accepted", sig.Format) + break + } + if !isAlgoCompatible(algo, sig.Format) { + authErr = fmt.Errorf("ssh: signature %q not compatible with selected algorithm %q", sig.Format, algo) + break + } + + signedData := buildDataSignedForAuth(sessionID, userAuthReq, algo, pubKeyData) + + if err := pubKey.Verify(signedData, sig); err != nil { + return nil, err + } + + authErr = candidate.result + perms = candidate.perms + } + case "gssapi-with-mic": + if authConfig.GSSAPIWithMICConfig == nil { + authErr = errors.New("ssh: gssapi-with-mic auth not configured") + break + } + gssapiConfig := authConfig.GSSAPIWithMICConfig + userAuthRequestGSSAPI, err := parseGSSAPIPayload(userAuthReq.Payload) + if err != nil { + return nil, parseError(msgUserAuthRequest) + } + // OpenSSH supports Kerberos V5 mechanism only for GSS-API authentication. + if userAuthRequestGSSAPI.N == 0 { + authErr = fmt.Errorf("ssh: Mechanism negotiation is not supported") + break + } + var i uint32 + present := false + for i = 0; i < userAuthRequestGSSAPI.N; i++ { + if userAuthRequestGSSAPI.OIDS[i].Equal(krb5Mesh) { + present = true + break + } + } + if !present { + authErr = fmt.Errorf("ssh: GSSAPI authentication must use the Kerberos V5 mechanism") + break + } + // Initial server response, see RFC 4462 section 3.3. + if err := s.transport.writePacket(Marshal(&userAuthGSSAPIResponse{ + SupportMech: krb5OID, + })); err != nil { + return nil, err + } + // Exchange token, see RFC 4462 section 3.4. + packet, err := s.transport.readPacket() + if err != nil { + return nil, err + } + userAuthGSSAPITokenReq := &userAuthGSSAPIToken{} + if err := Unmarshal(packet, userAuthGSSAPITokenReq); err != nil { + return nil, err + } + authErr, perms, err = gssExchangeToken(gssapiConfig, userAuthGSSAPITokenReq.Token, s, sessionID, + userAuthReq) + if err != nil { + return nil, err + } + default: + authErr = fmt.Errorf("ssh: unknown method %q", userAuthReq.Method) + } + + authErrs = append(authErrs, authErr) + + if config.AuthLogCallback != nil { + config.AuthLogCallback(s, userAuthReq.Method, authErr) + } + + var bannerErr *BannerError + if errors.As(authErr, &bannerErr) { + if bannerErr.Message != "" { + if err := s.SendAuthBanner(bannerErr.Message); err != nil { + return nil, err + } + } + } + + if authErr == nil { + break userAuthLoop + } + + var failureMsg userAuthFailureMsg + + if partialSuccess, ok := authErr.(*PartialSuccessError); ok { + // After a partial success error we don't allow changing the user + // name and execute the NoClientAuthCallback. + partialSuccessReturned = true + + // In case a partial success is returned, the server may send + // a new set of authentication methods. + authConfig = partialSuccess.Next + + // Reset pubkey cache, as the new PublicKeyCallback might + // accept a different set of public keys. + cache = pubKeyCache{} + + // Send back a partial success message to the user. + failureMsg.PartialSuccess = true + } else { + // Allow initial attempt of 'none' without penalty. + if authFailures > 0 || userAuthReq.Method != "none" || noneAuthCount != 1 { + authFailures++ + } + if config.MaxAuthTries > 0 && authFailures >= config.MaxAuthTries { + // If we have hit the max attempts, don't bother sending the + // final SSH_MSG_USERAUTH_FAILURE message, since there are + // no more authentication methods which can be attempted, + // and this message may cause the client to re-attempt + // authentication while we send the disconnect message. + // Continue, and trigger the disconnect at the start of + // the loop. + // + // The SSH specification is somewhat confusing about this, + // RFC 4252 Section 5.1 requires each authentication failure + // be responded to with a respective SSH_MSG_USERAUTH_FAILURE + // message, but Section 4 says the server should disconnect + // after some number of attempts, but it isn't explicit which + // message should take precedence (i.e. should there be a failure + // message than a disconnect message, or if we are going to + // disconnect, should we only send that message.) + // + // Either way, OpenSSH disconnects immediately after the last + // failed authentication attempt, and given they are typically + // considered the golden implementation it seems reasonable + // to match that behavior. + continue + } + } + + if authConfig.PasswordCallback != nil { + failureMsg.Methods = append(failureMsg.Methods, "password") + } + if authConfig.PublicKeyCallback != nil { + failureMsg.Methods = append(failureMsg.Methods, "publickey") + } + if authConfig.KeyboardInteractiveCallback != nil { + failureMsg.Methods = append(failureMsg.Methods, "keyboard-interactive") + } + if authConfig.GSSAPIWithMICConfig != nil && authConfig.GSSAPIWithMICConfig.Server != nil && + authConfig.GSSAPIWithMICConfig.AllowLogin != nil { + failureMsg.Methods = append(failureMsg.Methods, "gssapi-with-mic") + } + + if len(failureMsg.Methods) == 0 { + return nil, errors.New("ssh: no authentication methods available") + } + + if err := s.transport.writePacket(Marshal(&failureMsg)); err != nil { + return nil, err + } + } + + if err := s.transport.writePacket([]byte{msgUserAuthSuccess}); err != nil { + return nil, err + } + return perms, nil +} + +// sshClientKeyboardInteractive implements a ClientKeyboardInteractive by +// asking the client on the other side of a ServerConn. +type sshClientKeyboardInteractive struct { + *connection +} + +func (c *sshClientKeyboardInteractive) Challenge(name, instruction string, questions []string, echos []bool) (answers []string, err error) { + if len(questions) != len(echos) { + return nil, errors.New("ssh: echos and questions must have equal length") + } + + var prompts []byte + for i := range questions { + prompts = appendString(prompts, questions[i]) + prompts = appendBool(prompts, echos[i]) + } + + if err := c.transport.writePacket(Marshal(&userAuthInfoRequestMsg{ + Name: name, + Instruction: instruction, + NumPrompts: uint32(len(questions)), + Prompts: prompts, + })); err != nil { + return nil, err + } + + packet, err := c.transport.readPacket() + if err != nil { + return nil, err + } + if packet[0] != msgUserAuthInfoResponse { + return nil, unexpectedMessageError(msgUserAuthInfoResponse, packet[0]) + } + packet = packet[1:] + + n, packet, ok := parseUint32(packet) + if !ok || int(n) != len(questions) { + return nil, parseError(msgUserAuthInfoResponse) + } + + for i := uint32(0); i < n; i++ { + ans, rest, ok := parseString(packet) + if !ok { + return nil, parseError(msgUserAuthInfoResponse) + } + + answers = append(answers, string(ans)) + packet = rest + } + if len(packet) != 0 { + return nil, errors.New("ssh: junk at end of message") + } + + return answers, nil +} diff --git a/tempfork/sshtest/ssh/server_multi_auth_test.go b/tempfork/sshtest/ssh/server_multi_auth_test.go new file mode 100644 index 000000000..3b3980243 --- /dev/null +++ b/tempfork/sshtest/ssh/server_multi_auth_test.go @@ -0,0 +1,412 @@ +// Copyright 2024 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "bytes" + "errors" + "fmt" + "strings" + "testing" +) + +func doClientServerAuth(t *testing.T, serverConfig *ServerConfig, clientConfig *ClientConfig) ([]error, error) { + c1, c2, err := netPipe() + if err != nil { + t.Fatalf("netPipe: %v", err) + } + defer c1.Close() + defer c2.Close() + + var serverAuthErrors []error + + serverConfig.AddHostKey(testSigners["rsa"]) + serverConfig.AuthLogCallback = func(conn ConnMetadata, method string, err error) { + serverAuthErrors = append(serverAuthErrors, err) + } + go newServer(c1, serverConfig) + c, _, _, err := NewClientConn(c2, "", clientConfig) + if err == nil { + c.Close() + } + return serverAuthErrors, err +} + +func TestMultiStepAuth(t *testing.T) { + // This user can login with password, public key or public key + password. + username := "testuser" + // This user can login with public key + password only. + usernameSecondFactor := "testuser_second_factor" + errPwdAuthFailed := errors.New("password auth failed") + errWrongSequence := errors.New("wrong sequence") + + serverConfig := &ServerConfig{ + PasswordCallback: func(conn ConnMetadata, password []byte) (*Permissions, error) { + if conn.User() == usernameSecondFactor { + return nil, errWrongSequence + } + if conn.User() == username && string(password) == clientPassword { + return nil, nil + } + return nil, errPwdAuthFailed + }, + PublicKeyCallback: func(conn ConnMetadata, key PublicKey) (*Permissions, error) { + if bytes.Equal(key.Marshal(), testPublicKeys["rsa"].Marshal()) { + if conn.User() == usernameSecondFactor { + return nil, &PartialSuccessError{ + Next: ServerAuthCallbacks{ + PasswordCallback: func(conn ConnMetadata, password []byte) (*Permissions, error) { + if string(password) == clientPassword { + return nil, nil + } + return nil, errPwdAuthFailed + }, + }, + } + } + return nil, nil + } + return nil, fmt.Errorf("pubkey for %q not acceptable", conn.User()) + }, + } + + clientConfig := &ClientConfig{ + User: usernameSecondFactor, + Auth: []AuthMethod{ + PublicKeys(testSigners["rsa"]), + Password(clientPassword), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + + serverAuthErrors, err := doClientServerAuth(t, serverConfig, clientConfig) + if err != nil { + t.Fatalf("client login error: %s", err) + } + + // The error sequence is: + // - no auth passed yet + // - partial success + // - nil + if len(serverAuthErrors) != 3 { + t.Fatalf("unexpected number of server auth errors: %v, errors: %+v", len(serverAuthErrors), serverAuthErrors) + } + if _, ok := serverAuthErrors[1].(*PartialSuccessError); !ok { + t.Fatalf("expected partial success error, got: %v", serverAuthErrors[1]) + } + // Now test a wrong sequence. + clientConfig.Auth = []AuthMethod{ + Password(clientPassword), + PublicKeys(testSigners["rsa"]), + } + + serverAuthErrors, err = doClientServerAuth(t, serverConfig, clientConfig) + if err == nil { + t.Fatal("client login with wrong sequence must fail") + } + // The error sequence is: + // - no auth passed yet + // - wrong sequence + // - partial success + if len(serverAuthErrors) != 3 { + t.Fatalf("unexpected number of server auth errors: %v, errors: %+v", len(serverAuthErrors), serverAuthErrors) + } + if serverAuthErrors[1] != errWrongSequence { + t.Fatal("server not returned wrong sequence") + } + if _, ok := serverAuthErrors[2].(*PartialSuccessError); !ok { + t.Fatalf("expected partial success error, got: %v", serverAuthErrors[2]) + } + // Now test using a correct sequence but a wrong password before the right + // one. + n := 0 + passwords := []string{"WRONG", "WRONG", clientPassword} + clientConfig.Auth = []AuthMethod{ + PublicKeys(testSigners["rsa"]), + RetryableAuthMethod(PasswordCallback(func() (string, error) { + p := passwords[n] + n++ + return p, nil + }), 3), + } + + serverAuthErrors, err = doClientServerAuth(t, serverConfig, clientConfig) + if err != nil { + t.Fatalf("client login error: %s", err) + } + // The error sequence is: + // - no auth passed yet + // - partial success + // - wrong password + // - wrong password + // - nil + if len(serverAuthErrors) != 5 { + t.Fatalf("unexpected number of server auth errors: %v, errors: %+v", len(serverAuthErrors), serverAuthErrors) + } + if _, ok := serverAuthErrors[1].(*PartialSuccessError); !ok { + t.Fatal("server not returned partial success") + } + if serverAuthErrors[2] != errPwdAuthFailed { + t.Fatal("server not returned password authentication failed") + } + if serverAuthErrors[3] != errPwdAuthFailed { + t.Fatal("server not returned password authentication failed") + } + // Only password authentication should fail. + clientConfig.Auth = []AuthMethod{ + Password(clientPassword), + } + + serverAuthErrors, err = doClientServerAuth(t, serverConfig, clientConfig) + if err == nil { + t.Fatal("client login with password only must fail") + } + // The error sequence is: + // - no auth passed yet + // - wrong sequence + if len(serverAuthErrors) != 2 { + t.Fatalf("unexpected number of server auth errors: %v, errors: %+v", len(serverAuthErrors), serverAuthErrors) + } + if serverAuthErrors[1] != errWrongSequence { + t.Fatal("server not returned wrong sequence") + } + + // Only public key authentication should fail. + clientConfig.Auth = []AuthMethod{ + PublicKeys(testSigners["rsa"]), + } + + serverAuthErrors, err = doClientServerAuth(t, serverConfig, clientConfig) + if err == nil { + t.Fatal("client login with public key only must fail") + } + // The error sequence is: + // - no auth passed yet + // - partial success + if len(serverAuthErrors) != 2 { + t.Fatalf("unexpected number of server auth errors: %v, errors: %+v", len(serverAuthErrors), serverAuthErrors) + } + if _, ok := serverAuthErrors[1].(*PartialSuccessError); !ok { + t.Fatal("server not returned partial success") + } + + // Public key and wrong password. + clientConfig.Auth = []AuthMethod{ + PublicKeys(testSigners["rsa"]), + Password("WRONG"), + } + + serverAuthErrors, err = doClientServerAuth(t, serverConfig, clientConfig) + if err == nil { + t.Fatal("client login with wrong password after public key must fail") + } + // The error sequence is: + // - no auth passed yet + // - partial success + // - password auth failed + if len(serverAuthErrors) != 3 { + t.Fatalf("unexpected number of server auth errors: %v, errors: %+v", len(serverAuthErrors), serverAuthErrors) + } + if _, ok := serverAuthErrors[1].(*PartialSuccessError); !ok { + t.Fatal("server not returned partial success") + } + if serverAuthErrors[2] != errPwdAuthFailed { + t.Fatal("server not returned password authentication failed") + } + + // Public key, public key again and then correct password. Public key + // authentication is attempted only once because the partial success error + // returns only "password" as the allowed authentication method. + clientConfig.Auth = []AuthMethod{ + PublicKeys(testSigners["rsa"]), + PublicKeys(testSigners["rsa"]), + Password(clientPassword), + } + + serverAuthErrors, err = doClientServerAuth(t, serverConfig, clientConfig) + if err != nil { + t.Fatalf("client login error: %s", err) + } + // The error sequence is: + // - no auth passed yet + // - partial success + // - nil + if len(serverAuthErrors) != 3 { + t.Fatalf("unexpected number of server auth errors: %v, errors: %+v", len(serverAuthErrors), serverAuthErrors) + } + if _, ok := serverAuthErrors[1].(*PartialSuccessError); !ok { + t.Fatal("server not returned partial success") + } + + // The unrestricted username can do anything + clientConfig = &ClientConfig{ + User: username, + Auth: []AuthMethod{ + PublicKeys(testSigners["rsa"]), + Password(clientPassword), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + + _, err = doClientServerAuth(t, serverConfig, clientConfig) + if err != nil { + t.Fatalf("unrestricted client login error: %s", err) + } + + clientConfig = &ClientConfig{ + User: username, + Auth: []AuthMethod{ + PublicKeys(testSigners["rsa"]), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + + _, err = doClientServerAuth(t, serverConfig, clientConfig) + if err != nil { + t.Fatalf("unrestricted client login error: %s", err) + } + + clientConfig = &ClientConfig{ + User: username, + Auth: []AuthMethod{ + Password(clientPassword), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + + _, err = doClientServerAuth(t, serverConfig, clientConfig) + if err != nil { + t.Fatalf("unrestricted client login error: %s", err) + } +} + +func TestDynamicAuthCallbacks(t *testing.T) { + user1 := "user1" + user2 := "user2" + errInvalidCredentials := errors.New("invalid credentials") + + serverConfig := &ServerConfig{ + NoClientAuth: true, + NoClientAuthCallback: func(conn ConnMetadata) (*Permissions, error) { + switch conn.User() { + case user1: + return nil, &PartialSuccessError{ + Next: ServerAuthCallbacks{ + PasswordCallback: func(conn ConnMetadata, password []byte) (*Permissions, error) { + if conn.User() == user1 && string(password) == clientPassword { + return nil, nil + } + return nil, errInvalidCredentials + }, + }, + } + case user2: + return nil, &PartialSuccessError{ + Next: ServerAuthCallbacks{ + PublicKeyCallback: func(conn ConnMetadata, key PublicKey) (*Permissions, error) { + if bytes.Equal(key.Marshal(), testPublicKeys["rsa"].Marshal()) { + if conn.User() == user2 { + return nil, nil + } + } + return nil, errInvalidCredentials + }, + }, + } + default: + return nil, errInvalidCredentials + } + }, + } + + clientConfig := &ClientConfig{ + User: user1, + Auth: []AuthMethod{ + Password(clientPassword), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + + serverAuthErrors, err := doClientServerAuth(t, serverConfig, clientConfig) + if err != nil { + t.Fatalf("client login error: %s", err) + } + // The error sequence is: + // - partial success + // - nil + if len(serverAuthErrors) != 2 { + t.Fatalf("unexpected number of server auth errors: %v, errors: %+v", len(serverAuthErrors), serverAuthErrors) + } + if _, ok := serverAuthErrors[0].(*PartialSuccessError); !ok { + t.Fatal("server not returned partial success") + } + + clientConfig = &ClientConfig{ + User: user2, + Auth: []AuthMethod{ + PublicKeys(testSigners["rsa"]), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + + serverAuthErrors, err = doClientServerAuth(t, serverConfig, clientConfig) + if err != nil { + t.Fatalf("client login error: %s", err) + } + // The error sequence is: + // - partial success + // - nil + if len(serverAuthErrors) != 2 { + t.Fatalf("unexpected number of server auth errors: %v, errors: %+v", len(serverAuthErrors), serverAuthErrors) + } + if _, ok := serverAuthErrors[0].(*PartialSuccessError); !ok { + t.Fatal("server not returned partial success") + } + + // user1 cannot login with public key + clientConfig = &ClientConfig{ + User: user1, + Auth: []AuthMethod{ + PublicKeys(testSigners["rsa"]), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + + serverAuthErrors, err = doClientServerAuth(t, serverConfig, clientConfig) + if err == nil { + t.Fatal("user1 login with public key must fail") + } + if !strings.Contains(err.Error(), "no supported methods remain") { + t.Errorf("got %v, expected 'no supported methods remain'", err) + } + if len(serverAuthErrors) != 1 { + t.Fatalf("unexpected number of server auth errors: %v, errors: %+v", len(serverAuthErrors), serverAuthErrors) + } + if _, ok := serverAuthErrors[0].(*PartialSuccessError); !ok { + t.Fatal("server not returned partial success") + } + // user2 cannot login with password + clientConfig = &ClientConfig{ + User: user2, + Auth: []AuthMethod{ + Password(clientPassword), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + + serverAuthErrors, err = doClientServerAuth(t, serverConfig, clientConfig) + if err == nil { + t.Fatal("user2 login with password must fail") + } + if !strings.Contains(err.Error(), "no supported methods remain") { + t.Errorf("got %v, expected 'no supported methods remain'", err) + } + if len(serverAuthErrors) != 1 { + t.Fatalf("unexpected number of server auth errors: %v, errors: %+v", len(serverAuthErrors), serverAuthErrors) + } + if _, ok := serverAuthErrors[0].(*PartialSuccessError); !ok { + t.Fatal("server not returned partial success") + } +} diff --git a/tempfork/sshtest/ssh/server_test.go b/tempfork/sshtest/ssh/server_test.go new file mode 100644 index 000000000..c2b24f47c --- /dev/null +++ b/tempfork/sshtest/ssh/server_test.go @@ -0,0 +1,478 @@ +// Copyright 2023 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "bytes" + "errors" + "fmt" + "io" + "net" + "reflect" + "strings" + "sync/atomic" + "testing" + "time" +) + +func TestClientAuthRestrictedPublicKeyAlgos(t *testing.T) { + for _, tt := range []struct { + name string + key Signer + wantError bool + }{ + {"rsa", testSigners["rsa"], false}, + {"dsa", testSigners["dsa"], true}, + {"ed25519", testSigners["ed25519"], true}, + } { + c1, c2, err := netPipe() + if err != nil { + t.Fatalf("netPipe: %v", err) + } + defer c1.Close() + defer c2.Close() + serverConf := &ServerConfig{ + PublicKeyAuthAlgorithms: []string{KeyAlgoRSASHA256, KeyAlgoRSASHA512}, + PublicKeyCallback: func(conn ConnMetadata, key PublicKey) (*Permissions, error) { + return nil, nil + }, + } + serverConf.AddHostKey(testSigners["ecdsap256"]) + + done := make(chan struct{}) + go func() { + defer close(done) + NewServerConn(c1, serverConf) + }() + + clientConf := ClientConfig{ + User: "user", + Auth: []AuthMethod{ + PublicKeys(tt.key), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + + _, _, _, err = NewClientConn(c2, "", &clientConf) + if err != nil { + if !tt.wantError { + t.Errorf("%s: got unexpected error %q", tt.name, err.Error()) + } + } else if tt.wantError { + t.Errorf("%s: succeeded, but want error", tt.name) + } + <-done + } +} + +func TestMaxAuthTriesNoneMethod(t *testing.T) { + username := "testuser" + serverConfig := &ServerConfig{ + MaxAuthTries: 2, + PasswordCallback: func(conn ConnMetadata, password []byte) (*Permissions, error) { + if conn.User() == username && string(password) == clientPassword { + return nil, nil + } + return nil, errors.New("invalid credentials") + }, + } + c1, c2, err := netPipe() + if err != nil { + t.Fatalf("netPipe: %v", err) + } + defer c1.Close() + defer c2.Close() + + var serverAuthErrors []error + + serverConfig.AddHostKey(testSigners["rsa"]) + serverConfig.AuthLogCallback = func(conn ConnMetadata, method string, err error) { + serverAuthErrors = append(serverAuthErrors, err) + } + go newServer(c1, serverConfig) + + clientConfig := ClientConfig{ + User: username, + HostKeyCallback: InsecureIgnoreHostKey(), + } + clientConfig.SetDefaults() + // Our client will send 'none' auth only once, so we need to send the + // requests manually. + c := &connection{ + sshConn: sshConn{ + conn: c2, + user: username, + clientVersion: []byte(packageVersion), + }, + } + c.serverVersion, err = exchangeVersions(c.sshConn.conn, c.clientVersion) + if err != nil { + t.Fatalf("unable to exchange version: %v", err) + } + c.transport = newClientTransport( + newTransport(c.sshConn.conn, clientConfig.Rand, true /* is client */), + c.clientVersion, c.serverVersion, &clientConfig, "", c.sshConn.RemoteAddr()) + if err := c.transport.waitSession(); err != nil { + t.Fatalf("unable to wait session: %v", err) + } + c.sessionID = c.transport.getSessionID() + if err := c.transport.writePacket(Marshal(&serviceRequestMsg{serviceUserAuth})); err != nil { + t.Fatalf("unable to send ssh-userauth message: %v", err) + } + packet, err := c.transport.readPacket() + if err != nil { + t.Fatal(err) + } + if len(packet) > 0 && packet[0] == msgExtInfo { + packet, err = c.transport.readPacket() + if err != nil { + t.Fatal(err) + } + } + var serviceAccept serviceAcceptMsg + if err := Unmarshal(packet, &serviceAccept); err != nil { + t.Fatal(err) + } + for i := 0; i <= serverConfig.MaxAuthTries; i++ { + auth := new(noneAuth) + _, _, err := auth.auth(c.sessionID, clientConfig.User, c.transport, clientConfig.Rand, nil) + if i < serverConfig.MaxAuthTries { + if err != nil { + t.Fatal(err) + } + continue + } + if err == nil { + t.Fatal("client: got no error") + } else if !strings.Contains(err.Error(), "too many authentication failures") { + t.Fatalf("client: got unexpected error: %v", err) + } + } + if len(serverAuthErrors) != 3 { + t.Fatalf("unexpected number of server auth errors: %v, errors: %+v", len(serverAuthErrors), serverAuthErrors) + } + for _, err := range serverAuthErrors { + if !errors.Is(err, ErrNoAuth) { + t.Errorf("go error: %v; want: %v", err, ErrNoAuth) + } + } +} + +func TestMaxAuthTriesFirstNoneAuthErrorIgnored(t *testing.T) { + username := "testuser" + serverConfig := &ServerConfig{ + MaxAuthTries: 1, + PasswordCallback: func(conn ConnMetadata, password []byte) (*Permissions, error) { + if conn.User() == username && string(password) == clientPassword { + return nil, nil + } + return nil, errors.New("invalid credentials") + }, + } + clientConfig := &ClientConfig{ + User: username, + Auth: []AuthMethod{ + Password(clientPassword), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + + serverAuthErrors, err := doClientServerAuth(t, serverConfig, clientConfig) + if err != nil { + t.Fatalf("client login error: %s", err) + } + if len(serverAuthErrors) != 2 { + t.Fatalf("unexpected number of server auth errors: %v, errors: %+v", len(serverAuthErrors), serverAuthErrors) + } + if !errors.Is(serverAuthErrors[0], ErrNoAuth) { + t.Errorf("go error: %v; want: %v", serverAuthErrors[0], ErrNoAuth) + } + if serverAuthErrors[1] != nil { + t.Errorf("unexpected error: %v", serverAuthErrors[1]) + } +} + +func TestNewServerConnValidationErrors(t *testing.T) { + serverConf := &ServerConfig{ + PublicKeyAuthAlgorithms: []string{CertAlgoRSAv01}, + } + c := &markerConn{} + _, _, _, err := NewServerConn(c, serverConf) + if err == nil { + t.Fatal("NewServerConn with invalid public key auth algorithms succeeded") + } + if !c.isClosed() { + t.Fatal("NewServerConn with invalid public key auth algorithms left connection open") + } + if c.isUsed() { + t.Fatal("NewServerConn with invalid public key auth algorithms used connection") + } + + serverConf = &ServerConfig{ + Config: Config{ + KeyExchanges: []string{kexAlgoDHGEXSHA256}, + }, + } + c = &markerConn{} + _, _, _, err = NewServerConn(c, serverConf) + if err == nil { + t.Fatal("NewServerConn with unsupported key exchange succeeded") + } + if !c.isClosed() { + t.Fatal("NewServerConn with unsupported key exchange left connection open") + } + if c.isUsed() { + t.Fatal("NewServerConn with unsupported key exchange used connection") + } +} + +func TestBannerError(t *testing.T) { + serverConfig := &ServerConfig{ + BannerCallback: func(ConnMetadata) string { + return "banner from BannerCallback" + }, + NoClientAuth: true, + NoClientAuthCallback: func(ConnMetadata) (*Permissions, error) { + err := &BannerError{ + Err: errors.New("error from NoClientAuthCallback"), + Message: "banner from NoClientAuthCallback", + } + return nil, fmt.Errorf("wrapped: %w", err) + }, + PasswordCallback: func(conn ConnMetadata, password []byte) (*Permissions, error) { + return &Permissions{}, nil + }, + PublicKeyCallback: func(conn ConnMetadata, key PublicKey) (*Permissions, error) { + return nil, &BannerError{ + Err: errors.New("error from PublicKeyCallback"), + Message: "banner from PublicKeyCallback", + } + }, + KeyboardInteractiveCallback: func(conn ConnMetadata, client KeyboardInteractiveChallenge) (*Permissions, error) { + return nil, &BannerError{ + Err: nil, // make sure that a nil inner error is allowed + Message: "banner from KeyboardInteractiveCallback", + } + }, + } + serverConfig.AddHostKey(testSigners["rsa"]) + + var banners []string + clientConfig := &ClientConfig{ + User: "test", + Auth: []AuthMethod{ + PublicKeys(testSigners["rsa"]), + KeyboardInteractive(func(name, instruction string, questions []string, echos []bool) ([]string, error) { + return []string{"letmein"}, nil + }), + Password(clientPassword), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + BannerCallback: func(msg string) error { + banners = append(banners, msg) + return nil + }, + } + + c1, c2, err := netPipe() + if err != nil { + t.Fatalf("netPipe: %v", err) + } + defer c1.Close() + defer c2.Close() + go newServer(c1, serverConfig) + c, _, _, err := NewClientConn(c2, "", clientConfig) + if err != nil { + t.Fatalf("client connection failed: %v", err) + } + defer c.Close() + + wantBanners := []string{ + "banner from BannerCallback", + "banner from NoClientAuthCallback", + "banner from PublicKeyCallback", + "banner from KeyboardInteractiveCallback", + } + if !reflect.DeepEqual(banners, wantBanners) { + t.Errorf("got banners:\n%q\nwant banners:\n%q", banners, wantBanners) + } +} + +func TestPublicKeyCallbackLastSeen(t *testing.T) { + var lastSeenKey PublicKey + + c1, c2, err := netPipe() + if err != nil { + t.Fatalf("netPipe: %v", err) + } + defer c1.Close() + defer c2.Close() + serverConf := &ServerConfig{ + PublicKeyCallback: func(conn ConnMetadata, key PublicKey) (*Permissions, error) { + lastSeenKey = key + fmt.Printf("seen %#v\n", key) + if _, ok := key.(*dsaPublicKey); !ok { + return nil, errors.New("nope") + } + return nil, nil + }, + } + serverConf.AddHostKey(testSigners["ecdsap256"]) + + done := make(chan struct{}) + go func() { + defer close(done) + NewServerConn(c1, serverConf) + }() + + clientConf := ClientConfig{ + User: "user", + Auth: []AuthMethod{ + PublicKeys(testSigners["rsa"], testSigners["dsa"], testSigners["ed25519"]), + }, + HostKeyCallback: InsecureIgnoreHostKey(), + } + + _, _, _, err = NewClientConn(c2, "", &clientConf) + if err != nil { + t.Fatal(err) + } + <-done + + expectedPublicKey := testSigners["dsa"].PublicKey().Marshal() + lastSeenMarshalled := lastSeenKey.Marshal() + if !bytes.Equal(lastSeenMarshalled, expectedPublicKey) { + t.Errorf("unexpected key: got %#v, want %#v", lastSeenKey, testSigners["dsa"].PublicKey()) + } +} + +func TestPreAuthConnAndBanners(t *testing.T) { + testDone := make(chan struct{}) + defer close(testDone) + + authConnc := make(chan ServerPreAuthConn, 1) + serverConfig := &ServerConfig{ + PreAuthConnCallback: func(c ServerPreAuthConn) { + t.Logf("got ServerPreAuthConn: %v", c) + authConnc <- c // for use later in the test + for _, s := range []string{"hello1", "hello2"} { + if err := c.SendAuthBanner(s); err != nil { + t.Errorf("failed to send banner %q: %v", s, err) + } + } + // Now start a goroutine to spam SendAuthBanner in hopes + // of hitting a race. + go func() { + for { + select { + case <-testDone: + return + default: + if err := c.SendAuthBanner("attempted-race"); err != nil && err != errSendBannerPhase { + t.Errorf("unexpected error from SendAuthBanner: %v", err) + } + time.Sleep(5 * time.Millisecond) + } + } + }() + }, + NoClientAuth: true, + NoClientAuthCallback: func(ConnMetadata) (*Permissions, error) { + t.Logf("got NoClientAuthCallback") + return &Permissions{}, nil + }, + } + serverConfig.AddHostKey(testSigners["rsa"]) + + var banners []string + clientConfig := &ClientConfig{ + User: "test", + HostKeyCallback: InsecureIgnoreHostKey(), + BannerCallback: func(msg string) error { + if msg != "attempted-race" { + banners = append(banners, msg) + } + return nil + }, + } + + c1, c2, err := netPipe() + if err != nil { + t.Fatalf("netPipe: %v", err) + } + defer c1.Close() + defer c2.Close() + go newServer(c1, serverConfig) + c, _, _, err := NewClientConn(c2, "", clientConfig) + if err != nil { + t.Fatalf("client connection failed: %v", err) + } + defer c.Close() + + wantBanners := []string{ + "hello1", + "hello2", + } + if !reflect.DeepEqual(banners, wantBanners) { + t.Errorf("got banners:\n%q\nwant banners:\n%q", banners, wantBanners) + } + + // Now that we're authenticated, verify that use of SendBanner + // is an error. + var bc ServerPreAuthConn + select { + case bc = <-authConnc: + default: + t.Fatal("expected ServerPreAuthConn") + } + if err := bc.SendAuthBanner("wrong-phase"); err == nil { + t.Error("unexpected success of SendAuthBanner after authentication") + } else if err != errSendBannerPhase { + t.Errorf("unexpected error: %v; want %v", err, errSendBannerPhase) + } +} + +type markerConn struct { + closed uint32 + used uint32 +} + +func (c *markerConn) isClosed() bool { + return atomic.LoadUint32(&c.closed) != 0 +} + +func (c *markerConn) isUsed() bool { + return atomic.LoadUint32(&c.used) != 0 +} + +func (c *markerConn) Close() error { + atomic.StoreUint32(&c.closed, 1) + return nil +} + +func (c *markerConn) Read(b []byte) (n int, err error) { + atomic.StoreUint32(&c.used, 1) + if atomic.LoadUint32(&c.closed) != 0 { + return 0, net.ErrClosed + } else { + return 0, io.EOF + } +} + +func (c *markerConn) Write(b []byte) (n int, err error) { + atomic.StoreUint32(&c.used, 1) + if atomic.LoadUint32(&c.closed) != 0 { + return 0, net.ErrClosed + } else { + return 0, io.ErrClosedPipe + } +} + +func (*markerConn) LocalAddr() net.Addr { return nil } +func (*markerConn) RemoteAddr() net.Addr { return nil } + +func (*markerConn) SetDeadline(t time.Time) error { return nil } +func (*markerConn) SetReadDeadline(t time.Time) error { return nil } +func (*markerConn) SetWriteDeadline(t time.Time) error { return nil } diff --git a/tempfork/sshtest/ssh/session.go b/tempfork/sshtest/ssh/session.go new file mode 100644 index 000000000..acef62259 --- /dev/null +++ b/tempfork/sshtest/ssh/session.go @@ -0,0 +1,647 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +// Session implements an interactive session described in +// "RFC 4254, section 6". + +import ( + "bytes" + "encoding/binary" + "errors" + "fmt" + "io" + "sync" +) + +type Signal string + +// POSIX signals as listed in RFC 4254 Section 6.10. +const ( + SIGABRT Signal = "ABRT" + SIGALRM Signal = "ALRM" + SIGFPE Signal = "FPE" + SIGHUP Signal = "HUP" + SIGILL Signal = "ILL" + SIGINT Signal = "INT" + SIGKILL Signal = "KILL" + SIGPIPE Signal = "PIPE" + SIGQUIT Signal = "QUIT" + SIGSEGV Signal = "SEGV" + SIGTERM Signal = "TERM" + SIGUSR1 Signal = "USR1" + SIGUSR2 Signal = "USR2" +) + +var signals = map[Signal]int{ + SIGABRT: 6, + SIGALRM: 14, + SIGFPE: 8, + SIGHUP: 1, + SIGILL: 4, + SIGINT: 2, + SIGKILL: 9, + SIGPIPE: 13, + SIGQUIT: 3, + SIGSEGV: 11, + SIGTERM: 15, +} + +type TerminalModes map[uint8]uint32 + +// POSIX terminal mode flags as listed in RFC 4254 Section 8. +const ( + tty_OP_END = 0 + VINTR = 1 + VQUIT = 2 + VERASE = 3 + VKILL = 4 + VEOF = 5 + VEOL = 6 + VEOL2 = 7 + VSTART = 8 + VSTOP = 9 + VSUSP = 10 + VDSUSP = 11 + VREPRINT = 12 + VWERASE = 13 + VLNEXT = 14 + VFLUSH = 15 + VSWTCH = 16 + VSTATUS = 17 + VDISCARD = 18 + IGNPAR = 30 + PARMRK = 31 + INPCK = 32 + ISTRIP = 33 + INLCR = 34 + IGNCR = 35 + ICRNL = 36 + IUCLC = 37 + IXON = 38 + IXANY = 39 + IXOFF = 40 + IMAXBEL = 41 + IUTF8 = 42 // RFC 8160 + ISIG = 50 + ICANON = 51 + XCASE = 52 + ECHO = 53 + ECHOE = 54 + ECHOK = 55 + ECHONL = 56 + NOFLSH = 57 + TOSTOP = 58 + IEXTEN = 59 + ECHOCTL = 60 + ECHOKE = 61 + PENDIN = 62 + OPOST = 70 + OLCUC = 71 + ONLCR = 72 + OCRNL = 73 + ONOCR = 74 + ONLRET = 75 + CS7 = 90 + CS8 = 91 + PARENB = 92 + PARODD = 93 + TTY_OP_ISPEED = 128 + TTY_OP_OSPEED = 129 +) + +// A Session represents a connection to a remote command or shell. +type Session struct { + // Stdin specifies the remote process's standard input. + // If Stdin is nil, the remote process reads from an empty + // bytes.Buffer. + Stdin io.Reader + + // Stdout and Stderr specify the remote process's standard + // output and error. + // + // If either is nil, Run connects the corresponding file + // descriptor to an instance of io.Discard. There is a + // fixed amount of buffering that is shared for the two streams. + // If either blocks it may eventually cause the remote + // command to block. + Stdout io.Writer + Stderr io.Writer + + ch Channel // the channel backing this session + started bool // true once Start, Run or Shell is invoked. + copyFuncs []func() error + errors chan error // one send per copyFunc + + // true if pipe method is active + stdinpipe, stdoutpipe, stderrpipe bool + + // stdinPipeWriter is non-nil if StdinPipe has not been called + // and Stdin was specified by the user; it is the write end of + // a pipe connecting Session.Stdin to the stdin channel. + stdinPipeWriter io.WriteCloser + + exitStatus chan error +} + +// SendRequest sends an out-of-band channel request on the SSH channel +// underlying the session. +func (s *Session) SendRequest(name string, wantReply bool, payload []byte) (bool, error) { + return s.ch.SendRequest(name, wantReply, payload) +} + +func (s *Session) Close() error { + return s.ch.Close() +} + +// RFC 4254 Section 6.4. +type setenvRequest struct { + Name string + Value string +} + +// Setenv sets an environment variable that will be applied to any +// command executed by Shell or Run. +func (s *Session) Setenv(name, value string) error { + msg := setenvRequest{ + Name: name, + Value: value, + } + ok, err := s.ch.SendRequest("env", true, Marshal(&msg)) + if err == nil && !ok { + err = errors.New("ssh: setenv failed") + } + return err +} + +// RFC 4254 Section 6.2. +type ptyRequestMsg struct { + Term string + Columns uint32 + Rows uint32 + Width uint32 + Height uint32 + Modelist string +} + +// RequestPty requests the association of a pty with the session on the remote host. +func (s *Session) RequestPty(term string, h, w int, termmodes TerminalModes) error { + var tm []byte + for k, v := range termmodes { + kv := struct { + Key byte + Val uint32 + }{k, v} + + tm = append(tm, Marshal(&kv)...) + } + tm = append(tm, tty_OP_END) + req := ptyRequestMsg{ + Term: term, + Columns: uint32(w), + Rows: uint32(h), + Width: uint32(w * 8), + Height: uint32(h * 8), + Modelist: string(tm), + } + ok, err := s.ch.SendRequest("pty-req", true, Marshal(&req)) + if err == nil && !ok { + err = errors.New("ssh: pty-req failed") + } + return err +} + +// RFC 4254 Section 6.5. +type subsystemRequestMsg struct { + Subsystem string +} + +// RequestSubsystem requests the association of a subsystem with the session on the remote host. +// A subsystem is a predefined command that runs in the background when the ssh session is initiated +func (s *Session) RequestSubsystem(subsystem string) error { + msg := subsystemRequestMsg{ + Subsystem: subsystem, + } + ok, err := s.ch.SendRequest("subsystem", true, Marshal(&msg)) + if err == nil && !ok { + err = errors.New("ssh: subsystem request failed") + } + return err +} + +// RFC 4254 Section 6.7. +type ptyWindowChangeMsg struct { + Columns uint32 + Rows uint32 + Width uint32 + Height uint32 +} + +// WindowChange informs the remote host about a terminal window dimension change to h rows and w columns. +func (s *Session) WindowChange(h, w int) error { + req := ptyWindowChangeMsg{ + Columns: uint32(w), + Rows: uint32(h), + Width: uint32(w * 8), + Height: uint32(h * 8), + } + _, err := s.ch.SendRequest("window-change", false, Marshal(&req)) + return err +} + +// RFC 4254 Section 6.9. +type signalMsg struct { + Signal string +} + +// Signal sends the given signal to the remote process. +// sig is one of the SIG* constants. +func (s *Session) Signal(sig Signal) error { + msg := signalMsg{ + Signal: string(sig), + } + + _, err := s.ch.SendRequest("signal", false, Marshal(&msg)) + return err +} + +// RFC 4254 Section 6.5. +type execMsg struct { + Command string +} + +// Start runs cmd on the remote host. Typically, the remote +// server passes cmd to the shell for interpretation. +// A Session only accepts one call to Run, Start or Shell. +func (s *Session) Start(cmd string) error { + if s.started { + return errors.New("ssh: session already started") + } + req := execMsg{ + Command: cmd, + } + + ok, err := s.ch.SendRequest("exec", true, Marshal(&req)) + if err == nil && !ok { + err = fmt.Errorf("ssh: command %v failed", cmd) + } + if err != nil { + return err + } + return s.start() +} + +// Run runs cmd on the remote host. Typically, the remote +// server passes cmd to the shell for interpretation. +// A Session only accepts one call to Run, Start, Shell, Output, +// or CombinedOutput. +// +// The returned error is nil if the command runs, has no problems +// copying stdin, stdout, and stderr, and exits with a zero exit +// status. +// +// If the remote server does not send an exit status, an error of type +// *ExitMissingError is returned. If the command completes +// unsuccessfully or is interrupted by a signal, the error is of type +// *ExitError. Other error types may be returned for I/O problems. +func (s *Session) Run(cmd string) error { + err := s.Start(cmd) + if err != nil { + return err + } + return s.Wait() +} + +// Output runs cmd on the remote host and returns its standard output. +func (s *Session) Output(cmd string) ([]byte, error) { + if s.Stdout != nil { + return nil, errors.New("ssh: Stdout already set") + } + var b bytes.Buffer + s.Stdout = &b + err := s.Run(cmd) + return b.Bytes(), err +} + +type singleWriter struct { + b bytes.Buffer + mu sync.Mutex +} + +func (w *singleWriter) Write(p []byte) (int, error) { + w.mu.Lock() + defer w.mu.Unlock() + return w.b.Write(p) +} + +// CombinedOutput runs cmd on the remote host and returns its combined +// standard output and standard error. +func (s *Session) CombinedOutput(cmd string) ([]byte, error) { + if s.Stdout != nil { + return nil, errors.New("ssh: Stdout already set") + } + if s.Stderr != nil { + return nil, errors.New("ssh: Stderr already set") + } + var b singleWriter + s.Stdout = &b + s.Stderr = &b + err := s.Run(cmd) + return b.b.Bytes(), err +} + +// Shell starts a login shell on the remote host. A Session only +// accepts one call to Run, Start, Shell, Output, or CombinedOutput. +func (s *Session) Shell() error { + if s.started { + return errors.New("ssh: session already started") + } + + ok, err := s.ch.SendRequest("shell", true, nil) + if err == nil && !ok { + return errors.New("ssh: could not start shell") + } + if err != nil { + return err + } + return s.start() +} + +func (s *Session) start() error { + s.started = true + + type F func(*Session) + for _, setupFd := range []F{(*Session).stdin, (*Session).stdout, (*Session).stderr} { + setupFd(s) + } + + s.errors = make(chan error, len(s.copyFuncs)) + for _, fn := range s.copyFuncs { + go func(fn func() error) { + s.errors <- fn() + }(fn) + } + return nil +} + +// Wait waits for the remote command to exit. +// +// The returned error is nil if the command runs, has no problems +// copying stdin, stdout, and stderr, and exits with a zero exit +// status. +// +// If the remote server does not send an exit status, an error of type +// *ExitMissingError is returned. If the command completes +// unsuccessfully or is interrupted by a signal, the error is of type +// *ExitError. Other error types may be returned for I/O problems. +func (s *Session) Wait() error { + if !s.started { + return errors.New("ssh: session not started") + } + waitErr := <-s.exitStatus + + if s.stdinPipeWriter != nil { + s.stdinPipeWriter.Close() + } + var copyError error + for range s.copyFuncs { + if err := <-s.errors; err != nil && copyError == nil { + copyError = err + } + } + if waitErr != nil { + return waitErr + } + return copyError +} + +func (s *Session) wait(reqs <-chan *Request) error { + wm := Waitmsg{status: -1} + // Wait for msg channel to be closed before returning. + for msg := range reqs { + switch msg.Type { + case "exit-status": + wm.status = int(binary.BigEndian.Uint32(msg.Payload)) + case "exit-signal": + var sigval struct { + Signal string + CoreDumped bool + Error string + Lang string + } + if err := Unmarshal(msg.Payload, &sigval); err != nil { + return err + } + + // Must sanitize strings? + wm.signal = sigval.Signal + wm.msg = sigval.Error + wm.lang = sigval.Lang + default: + // This handles keepalives and matches + // OpenSSH's behaviour. + if msg.WantReply { + msg.Reply(false, nil) + } + } + } + if wm.status == 0 { + return nil + } + if wm.status == -1 { + // exit-status was never sent from server + if wm.signal == "" { + // signal was not sent either. RFC 4254 + // section 6.10 recommends against this + // behavior, but it is allowed, so we let + // clients handle it. + return &ExitMissingError{} + } + wm.status = 128 + if _, ok := signals[Signal(wm.signal)]; ok { + wm.status += signals[Signal(wm.signal)] + } + } + + return &ExitError{wm} +} + +// ExitMissingError is returned if a session is torn down cleanly, but +// the server sends no confirmation of the exit status. +type ExitMissingError struct{} + +func (e *ExitMissingError) Error() string { + return "wait: remote command exited without exit status or exit signal" +} + +func (s *Session) stdin() { + if s.stdinpipe { + return + } + var stdin io.Reader + if s.Stdin == nil { + stdin = new(bytes.Buffer) + } else { + r, w := io.Pipe() + go func() { + _, err := io.Copy(w, s.Stdin) + w.CloseWithError(err) + }() + stdin, s.stdinPipeWriter = r, w + } + s.copyFuncs = append(s.copyFuncs, func() error { + _, err := io.Copy(s.ch, stdin) + if err1 := s.ch.CloseWrite(); err == nil && err1 != io.EOF { + err = err1 + } + return err + }) +} + +func (s *Session) stdout() { + if s.stdoutpipe { + return + } + if s.Stdout == nil { + s.Stdout = io.Discard + } + s.copyFuncs = append(s.copyFuncs, func() error { + _, err := io.Copy(s.Stdout, s.ch) + return err + }) +} + +func (s *Session) stderr() { + if s.stderrpipe { + return + } + if s.Stderr == nil { + s.Stderr = io.Discard + } + s.copyFuncs = append(s.copyFuncs, func() error { + _, err := io.Copy(s.Stderr, s.ch.Stderr()) + return err + }) +} + +// sessionStdin reroutes Close to CloseWrite. +type sessionStdin struct { + io.Writer + ch Channel +} + +func (s *sessionStdin) Close() error { + return s.ch.CloseWrite() +} + +// StdinPipe returns a pipe that will be connected to the +// remote command's standard input when the command starts. +func (s *Session) StdinPipe() (io.WriteCloser, error) { + if s.Stdin != nil { + return nil, errors.New("ssh: Stdin already set") + } + if s.started { + return nil, errors.New("ssh: StdinPipe after process started") + } + s.stdinpipe = true + return &sessionStdin{s.ch, s.ch}, nil +} + +// StdoutPipe returns a pipe that will be connected to the +// remote command's standard output when the command starts. +// There is a fixed amount of buffering that is shared between +// stdout and stderr streams. If the StdoutPipe reader is +// not serviced fast enough it may eventually cause the +// remote command to block. +func (s *Session) StdoutPipe() (io.Reader, error) { + if s.Stdout != nil { + return nil, errors.New("ssh: Stdout already set") + } + if s.started { + return nil, errors.New("ssh: StdoutPipe after process started") + } + s.stdoutpipe = true + return s.ch, nil +} + +// StderrPipe returns a pipe that will be connected to the +// remote command's standard error when the command starts. +// There is a fixed amount of buffering that is shared between +// stdout and stderr streams. If the StderrPipe reader is +// not serviced fast enough it may eventually cause the +// remote command to block. +func (s *Session) StderrPipe() (io.Reader, error) { + if s.Stderr != nil { + return nil, errors.New("ssh: Stderr already set") + } + if s.started { + return nil, errors.New("ssh: StderrPipe after process started") + } + s.stderrpipe = true + return s.ch.Stderr(), nil +} + +// newSession returns a new interactive session on the remote host. +func newSession(ch Channel, reqs <-chan *Request) (*Session, error) { + s := &Session{ + ch: ch, + } + s.exitStatus = make(chan error, 1) + go func() { + s.exitStatus <- s.wait(reqs) + }() + + return s, nil +} + +// An ExitError reports unsuccessful completion of a remote command. +type ExitError struct { + Waitmsg +} + +func (e *ExitError) Error() string { + return e.Waitmsg.String() +} + +// Waitmsg stores the information about an exited remote command +// as reported by Wait. +type Waitmsg struct { + status int + signal string + msg string + lang string +} + +// ExitStatus returns the exit status of the remote command. +func (w Waitmsg) ExitStatus() int { + return w.status +} + +// Signal returns the exit signal of the remote command if +// it was terminated violently. +func (w Waitmsg) Signal() string { + return w.signal +} + +// Msg returns the exit message given by the remote command +func (w Waitmsg) Msg() string { + return w.msg +} + +// Lang returns the language tag. See RFC 3066 +func (w Waitmsg) Lang() string { + return w.lang +} + +func (w Waitmsg) String() string { + str := fmt.Sprintf("Process exited with status %v", w.status) + if w.signal != "" { + str += fmt.Sprintf(" from signal %v", w.signal) + } + if w.msg != "" { + str += fmt.Sprintf(". Reason was: %v", w.msg) + } + return str +} diff --git a/tempfork/sshtest/ssh/session_test.go b/tempfork/sshtest/ssh/session_test.go new file mode 100644 index 000000000..807a913e5 --- /dev/null +++ b/tempfork/sshtest/ssh/session_test.go @@ -0,0 +1,892 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +// Session tests. + +import ( + "bytes" + crypto_rand "crypto/rand" + "errors" + "io" + "math/rand" + "net" + "sync" + "testing" + + "golang.org/x/crypto/ssh/terminal" +) + +type serverType func(Channel, <-chan *Request, *testing.T) + +// dial constructs a new test server and returns a *ClientConn. +func dial(handler serverType, t *testing.T) *Client { + c1, c2, err := netPipe() + if err != nil { + t.Fatalf("netPipe: %v", err) + } + + var wg sync.WaitGroup + t.Cleanup(wg.Wait) + wg.Add(1) + go func() { + defer func() { + c1.Close() + wg.Done() + }() + conf := ServerConfig{ + NoClientAuth: true, + } + conf.AddHostKey(testSigners["rsa"]) + + conn, chans, reqs, err := NewServerConn(c1, &conf) + if err != nil { + t.Errorf("Unable to handshake: %v", err) + return + } + wg.Add(1) + go func() { + DiscardRequests(reqs) + wg.Done() + }() + + for newCh := range chans { + if newCh.ChannelType() != "session" { + newCh.Reject(UnknownChannelType, "unknown channel type") + continue + } + + ch, inReqs, err := newCh.Accept() + if err != nil { + t.Errorf("Accept: %v", err) + continue + } + wg.Add(1) + go func() { + handler(ch, inReqs, t) + wg.Done() + }() + } + if err := conn.Wait(); err != io.EOF { + t.Logf("server exit reason: %v", err) + } + }() + + config := &ClientConfig{ + User: "testuser", + HostKeyCallback: InsecureIgnoreHostKey(), + } + + conn, chans, reqs, err := NewClientConn(c2, "", config) + if err != nil { + t.Fatalf("unable to dial remote side: %v", err) + } + + return NewClient(conn, chans, reqs) +} + +// Test a simple string is returned to session.Stdout. +func TestSessionShell(t *testing.T) { + conn := dial(shellHandler, t) + defer conn.Close() + session, err := conn.NewSession() + if err != nil { + t.Fatalf("Unable to request new session: %v", err) + } + defer session.Close() + stdout := new(bytes.Buffer) + session.Stdout = stdout + if err := session.Shell(); err != nil { + t.Fatalf("Unable to execute command: %s", err) + } + if err := session.Wait(); err != nil { + t.Fatalf("Remote command did not exit cleanly: %v", err) + } + actual := stdout.String() + if actual != "golang" { + t.Fatalf("Remote shell did not return expected string: expected=golang, actual=%s", actual) + } +} + +// TODO(dfc) add support for Std{in,err}Pipe when the Server supports it. + +// Test a simple string is returned via StdoutPipe. +func TestSessionStdoutPipe(t *testing.T) { + conn := dial(shellHandler, t) + defer conn.Close() + session, err := conn.NewSession() + if err != nil { + t.Fatalf("Unable to request new session: %v", err) + } + defer session.Close() + stdout, err := session.StdoutPipe() + if err != nil { + t.Fatalf("Unable to request StdoutPipe(): %v", err) + } + var buf bytes.Buffer + if err := session.Shell(); err != nil { + t.Fatalf("Unable to execute command: %v", err) + } + done := make(chan bool, 1) + go func() { + if _, err := io.Copy(&buf, stdout); err != nil { + t.Errorf("Copy of stdout failed: %v", err) + } + done <- true + }() + if err := session.Wait(); err != nil { + t.Fatalf("Remote command did not exit cleanly: %v", err) + } + <-done + actual := buf.String() + if actual != "golang" { + t.Fatalf("Remote shell did not return expected string: expected=golang, actual=%s", actual) + } +} + +// Test that a simple string is returned via the Output helper, +// and that stderr is discarded. +func TestSessionOutput(t *testing.T) { + conn := dial(fixedOutputHandler, t) + defer conn.Close() + session, err := conn.NewSession() + if err != nil { + t.Fatalf("Unable to request new session: %v", err) + } + defer session.Close() + + buf, err := session.Output("") // cmd is ignored by fixedOutputHandler + if err != nil { + t.Error("Remote command did not exit cleanly:", err) + } + w := "this-is-stdout." + g := string(buf) + if g != w { + t.Error("Remote command did not return expected string:") + t.Logf("want %q", w) + t.Logf("got %q", g) + } +} + +// Test that both stdout and stderr are returned +// via the CombinedOutput helper. +func TestSessionCombinedOutput(t *testing.T) { + conn := dial(fixedOutputHandler, t) + defer conn.Close() + session, err := conn.NewSession() + if err != nil { + t.Fatalf("Unable to request new session: %v", err) + } + defer session.Close() + + buf, err := session.CombinedOutput("") // cmd is ignored by fixedOutputHandler + if err != nil { + t.Error("Remote command did not exit cleanly:", err) + } + const stdout = "this-is-stdout." + const stderr = "this-is-stderr." + g := string(buf) + if g != stdout+stderr && g != stderr+stdout { + t.Error("Remote command did not return expected string:") + t.Logf("want %q, or %q", stdout+stderr, stderr+stdout) + t.Logf("got %q", g) + } +} + +// Test non-0 exit status is returned correctly. +func TestExitStatusNonZero(t *testing.T) { + conn := dial(exitStatusNonZeroHandler, t) + defer conn.Close() + session, err := conn.NewSession() + if err != nil { + t.Fatalf("Unable to request new session: %v", err) + } + defer session.Close() + if err := session.Shell(); err != nil { + t.Fatalf("Unable to execute command: %v", err) + } + err = session.Wait() + if err == nil { + t.Fatalf("expected command to fail but it didn't") + } + e, ok := err.(*ExitError) + if !ok { + t.Fatalf("expected *ExitError but got %T", err) + } + if e.ExitStatus() != 15 { + t.Fatalf("expected command to exit with 15 but got %v", e.ExitStatus()) + } +} + +// Test 0 exit status is returned correctly. +func TestExitStatusZero(t *testing.T) { + conn := dial(exitStatusZeroHandler, t) + defer conn.Close() + session, err := conn.NewSession() + if err != nil { + t.Fatalf("Unable to request new session: %v", err) + } + defer session.Close() + + if err := session.Shell(); err != nil { + t.Fatalf("Unable to execute command: %v", err) + } + err = session.Wait() + if err != nil { + t.Fatalf("expected nil but got %v", err) + } +} + +// Test exit signal and status are both returned correctly. +func TestExitSignalAndStatus(t *testing.T) { + conn := dial(exitSignalAndStatusHandler, t) + defer conn.Close() + session, err := conn.NewSession() + if err != nil { + t.Fatalf("Unable to request new session: %v", err) + } + defer session.Close() + if err := session.Shell(); err != nil { + t.Fatalf("Unable to execute command: %v", err) + } + err = session.Wait() + if err == nil { + t.Fatalf("expected command to fail but it didn't") + } + e, ok := err.(*ExitError) + if !ok { + t.Fatalf("expected *ExitError but got %T", err) + } + if e.Signal() != "TERM" || e.ExitStatus() != 15 { + t.Fatalf("expected command to exit with signal TERM and status 15 but got signal %s and status %v", e.Signal(), e.ExitStatus()) + } +} + +// Test exit signal and status are both returned correctly. +func TestKnownExitSignalOnly(t *testing.T) { + conn := dial(exitSignalHandler, t) + defer conn.Close() + session, err := conn.NewSession() + if err != nil { + t.Fatalf("Unable to request new session: %v", err) + } + defer session.Close() + if err := session.Shell(); err != nil { + t.Fatalf("Unable to execute command: %v", err) + } + err = session.Wait() + if err == nil { + t.Fatalf("expected command to fail but it didn't") + } + e, ok := err.(*ExitError) + if !ok { + t.Fatalf("expected *ExitError but got %T", err) + } + if e.Signal() != "TERM" || e.ExitStatus() != 143 { + t.Fatalf("expected command to exit with signal TERM and status 143 but got signal %s and status %v", e.Signal(), e.ExitStatus()) + } +} + +// Test exit signal and status are both returned correctly. +func TestUnknownExitSignal(t *testing.T) { + conn := dial(exitSignalUnknownHandler, t) + defer conn.Close() + session, err := conn.NewSession() + if err != nil { + t.Fatalf("Unable to request new session: %v", err) + } + defer session.Close() + if err := session.Shell(); err != nil { + t.Fatalf("Unable to execute command: %v", err) + } + err = session.Wait() + if err == nil { + t.Fatalf("expected command to fail but it didn't") + } + e, ok := err.(*ExitError) + if !ok { + t.Fatalf("expected *ExitError but got %T", err) + } + if e.Signal() != "SYS" || e.ExitStatus() != 128 { + t.Fatalf("expected command to exit with signal SYS and status 128 but got signal %s and status %v", e.Signal(), e.ExitStatus()) + } +} + +func TestExitWithoutStatusOrSignal(t *testing.T) { + conn := dial(exitWithoutSignalOrStatus, t) + defer conn.Close() + session, err := conn.NewSession() + if err != nil { + t.Fatalf("Unable to request new session: %v", err) + } + defer session.Close() + if err := session.Shell(); err != nil { + t.Fatalf("Unable to execute command: %v", err) + } + err = session.Wait() + if err == nil { + t.Fatalf("expected command to fail but it didn't") + } + if _, ok := err.(*ExitMissingError); !ok { + t.Fatalf("got %T want *ExitMissingError", err) + } +} + +// windowTestBytes is the number of bytes that we'll send to the SSH server. +const windowTestBytes = 16000 * 200 + +// TestServerWindow writes random data to the server. The server is expected to echo +// the same data back, which is compared against the original. +func TestServerWindow(t *testing.T) { + origBuf := bytes.NewBuffer(make([]byte, 0, windowTestBytes)) + io.CopyN(origBuf, crypto_rand.Reader, windowTestBytes) + origBytes := origBuf.Bytes() + + conn := dial(echoHandler, t) + defer conn.Close() + session, err := conn.NewSession() + if err != nil { + t.Fatal(err) + } + defer session.Close() + + serverStdin, err := session.StdinPipe() + if err != nil { + t.Fatalf("StdinPipe failed: %v", err) + } + + result := make(chan []byte) + go func() { + defer close(result) + echoedBuf := bytes.NewBuffer(make([]byte, 0, windowTestBytes)) + serverStdout, err := session.StdoutPipe() + if err != nil { + t.Errorf("StdoutPipe failed: %v", err) + return + } + n, err := copyNRandomly("stdout", echoedBuf, serverStdout, windowTestBytes) + if err != nil && err != io.EOF { + t.Errorf("Read only %d bytes from server, expected %d: %v", n, windowTestBytes, err) + } + result <- echoedBuf.Bytes() + }() + + written, err := copyNRandomly("stdin", serverStdin, origBuf, windowTestBytes) + if err != nil { + t.Errorf("failed to copy origBuf to serverStdin: %v", err) + } else if written != windowTestBytes { + t.Errorf("Wrote only %d of %d bytes to server", written, windowTestBytes) + } + + echoedBytes := <-result + + if !bytes.Equal(origBytes, echoedBytes) { + t.Fatalf("Echoed buffer differed from original, orig %d, echoed %d", len(origBytes), len(echoedBytes)) + } +} + +// Verify the client can handle a keepalive packet from the server. +func TestClientHandlesKeepalives(t *testing.T) { + conn := dial(channelKeepaliveSender, t) + defer conn.Close() + session, err := conn.NewSession() + if err != nil { + t.Fatal(err) + } + defer session.Close() + if err := session.Shell(); err != nil { + t.Fatalf("Unable to execute command: %v", err) + } + err = session.Wait() + if err != nil { + t.Fatalf("expected nil but got: %v", err) + } +} + +type exitStatusMsg struct { + Status uint32 +} + +type exitSignalMsg struct { + Signal string + CoreDumped bool + Errmsg string + Lang string +} + +func handleTerminalRequests(in <-chan *Request) { + for req := range in { + ok := false + switch req.Type { + case "shell": + ok = true + if len(req.Payload) > 0 { + // We don't accept any commands, only the default shell. + ok = false + } + case "env": + ok = true + } + req.Reply(ok, nil) + } +} + +func newServerShell(ch Channel, in <-chan *Request, prompt string) *terminal.Terminal { + term := terminal.NewTerminal(ch, prompt) + go handleTerminalRequests(in) + return term +} + +func exitStatusZeroHandler(ch Channel, in <-chan *Request, t *testing.T) { + defer ch.Close() + // this string is returned to stdout + shell := newServerShell(ch, in, "> ") + readLine(shell, t) + sendStatus(0, ch, t) +} + +func exitStatusNonZeroHandler(ch Channel, in <-chan *Request, t *testing.T) { + defer ch.Close() + shell := newServerShell(ch, in, "> ") + readLine(shell, t) + sendStatus(15, ch, t) +} + +func exitSignalAndStatusHandler(ch Channel, in <-chan *Request, t *testing.T) { + defer ch.Close() + shell := newServerShell(ch, in, "> ") + readLine(shell, t) + sendStatus(15, ch, t) + sendSignal("TERM", ch, t) +} + +func exitSignalHandler(ch Channel, in <-chan *Request, t *testing.T) { + defer ch.Close() + shell := newServerShell(ch, in, "> ") + readLine(shell, t) + sendSignal("TERM", ch, t) +} + +func exitSignalUnknownHandler(ch Channel, in <-chan *Request, t *testing.T) { + defer ch.Close() + shell := newServerShell(ch, in, "> ") + readLine(shell, t) + sendSignal("SYS", ch, t) +} + +func exitWithoutSignalOrStatus(ch Channel, in <-chan *Request, t *testing.T) { + defer ch.Close() + shell := newServerShell(ch, in, "> ") + readLine(shell, t) +} + +func shellHandler(ch Channel, in <-chan *Request, t *testing.T) { + defer ch.Close() + // this string is returned to stdout + shell := newServerShell(ch, in, "golang") + readLine(shell, t) + sendStatus(0, ch, t) +} + +// Ignores the command, writes fixed strings to stderr and stdout. +// Strings are "this-is-stdout." and "this-is-stderr.". +func fixedOutputHandler(ch Channel, in <-chan *Request, t *testing.T) { + defer ch.Close() + _, err := ch.Read(nil) + + req, ok := <-in + if !ok { + t.Fatalf("error: expected channel request, got: %#v", err) + return + } + + // ignore request, always send some text + req.Reply(true, nil) + + _, err = io.WriteString(ch, "this-is-stdout.") + if err != nil { + t.Fatalf("error writing on server: %v", err) + } + _, err = io.WriteString(ch.Stderr(), "this-is-stderr.") + if err != nil { + t.Fatalf("error writing on server: %v", err) + } + sendStatus(0, ch, t) +} + +func readLine(shell *terminal.Terminal, t *testing.T) { + if _, err := shell.ReadLine(); err != nil && err != io.EOF { + t.Errorf("unable to read line: %v", err) + } +} + +func sendStatus(status uint32, ch Channel, t *testing.T) { + msg := exitStatusMsg{ + Status: status, + } + if _, err := ch.SendRequest("exit-status", false, Marshal(&msg)); err != nil { + t.Errorf("unable to send status: %v", err) + } +} + +func sendSignal(signal string, ch Channel, t *testing.T) { + sig := exitSignalMsg{ + Signal: signal, + CoreDumped: false, + Errmsg: "Process terminated", + Lang: "en-GB-oed", + } + if _, err := ch.SendRequest("exit-signal", false, Marshal(&sig)); err != nil { + t.Errorf("unable to send signal: %v", err) + } +} + +func discardHandler(ch Channel, t *testing.T) { + defer ch.Close() + io.Copy(io.Discard, ch) +} + +func echoHandler(ch Channel, in <-chan *Request, t *testing.T) { + defer ch.Close() + if n, err := copyNRandomly("echohandler", ch, ch, windowTestBytes); err != nil { + t.Errorf("short write, wrote %d, expected %d: %v ", n, windowTestBytes, err) + } +} + +// copyNRandomly copies n bytes from src to dst. It uses a variable, and random, +// buffer size to exercise more code paths. +func copyNRandomly(title string, dst io.Writer, src io.Reader, n int) (int, error) { + var ( + buf = make([]byte, 32*1024) + written int + remaining = n + ) + for remaining > 0 { + l := rand.Intn(1 << 15) + if remaining < l { + l = remaining + } + nr, er := src.Read(buf[:l]) + nw, ew := dst.Write(buf[:nr]) + remaining -= nw + written += nw + if ew != nil { + return written, ew + } + if nr != nw { + return written, io.ErrShortWrite + } + if er != nil && er != io.EOF { + return written, er + } + } + return written, nil +} + +func channelKeepaliveSender(ch Channel, in <-chan *Request, t *testing.T) { + defer ch.Close() + shell := newServerShell(ch, in, "> ") + readLine(shell, t) + if _, err := ch.SendRequest("keepalive@openssh.com", true, nil); err != nil { + t.Errorf("unable to send channel keepalive request: %v", err) + } + sendStatus(0, ch, t) +} + +func TestClientWriteEOF(t *testing.T) { + conn := dial(simpleEchoHandler, t) + defer conn.Close() + + session, err := conn.NewSession() + if err != nil { + t.Fatal(err) + } + defer session.Close() + stdin, err := session.StdinPipe() + if err != nil { + t.Fatalf("StdinPipe failed: %v", err) + } + stdout, err := session.StdoutPipe() + if err != nil { + t.Fatalf("StdoutPipe failed: %v", err) + } + + data := []byte(`0000`) + _, err = stdin.Write(data) + if err != nil { + t.Fatalf("Write failed: %v", err) + } + stdin.Close() + + res, err := io.ReadAll(stdout) + if err != nil { + t.Fatalf("Read failed: %v", err) + } + + if !bytes.Equal(data, res) { + t.Fatalf("Read differed from write, wrote: %v, read: %v", data, res) + } +} + +func simpleEchoHandler(ch Channel, in <-chan *Request, t *testing.T) { + defer ch.Close() + data, err := io.ReadAll(ch) + if err != nil { + t.Errorf("handler read error: %v", err) + } + _, err = ch.Write(data) + if err != nil { + t.Errorf("handler write error: %v", err) + } +} + +func TestSessionID(t *testing.T) { + c1, c2, err := netPipe() + if err != nil { + t.Fatalf("netPipe: %v", err) + } + defer c1.Close() + defer c2.Close() + + serverID := make(chan []byte, 1) + clientID := make(chan []byte, 1) + + serverConf := &ServerConfig{ + NoClientAuth: true, + } + serverConf.AddHostKey(testSigners["ecdsa"]) + clientConf := &ClientConfig{ + HostKeyCallback: InsecureIgnoreHostKey(), + User: "user", + } + + var wg sync.WaitGroup + t.Cleanup(wg.Wait) + + srvErrCh := make(chan error, 1) + wg.Add(1) + go func() { + defer wg.Done() + conn, chans, reqs, err := NewServerConn(c1, serverConf) + srvErrCh <- err + if err != nil { + return + } + serverID <- conn.SessionID() + wg.Add(1) + go func() { + DiscardRequests(reqs) + wg.Done() + }() + for ch := range chans { + ch.Reject(Prohibited, "") + } + }() + + cliErrCh := make(chan error, 1) + wg.Add(1) + go func() { + defer wg.Done() + conn, chans, reqs, err := NewClientConn(c2, "", clientConf) + cliErrCh <- err + if err != nil { + return + } + clientID <- conn.SessionID() + wg.Add(1) + go func() { + DiscardRequests(reqs) + wg.Done() + }() + for ch := range chans { + ch.Reject(Prohibited, "") + } + }() + + if err := <-srvErrCh; err != nil { + t.Fatalf("server handshake: %v", err) + } + + if err := <-cliErrCh; err != nil { + t.Fatalf("client handshake: %v", err) + } + + s := <-serverID + c := <-clientID + if bytes.Compare(s, c) != 0 { + t.Errorf("server session ID (%x) != client session ID (%x)", s, c) + } else if len(s) == 0 { + t.Errorf("client and server SessionID were empty.") + } +} + +type noReadConn struct { + readSeen bool + net.Conn +} + +func (c *noReadConn) Close() error { + return nil +} + +func (c *noReadConn) Read(b []byte) (int, error) { + c.readSeen = true + return 0, errors.New("noReadConn error") +} + +func TestInvalidServerConfiguration(t *testing.T) { + c1, c2, err := netPipe() + if err != nil { + t.Fatalf("netPipe: %v", err) + } + defer c1.Close() + defer c2.Close() + + serveConn := noReadConn{Conn: c1} + serverConf := &ServerConfig{} + + NewServerConn(&serveConn, serverConf) + if serveConn.readSeen { + t.Fatalf("NewServerConn attempted to Read() from Conn while configuration is missing host key") + } + + serverConf.AddHostKey(testSigners["ecdsa"]) + + NewServerConn(&serveConn, serverConf) + if serveConn.readSeen { + t.Fatalf("NewServerConn attempted to Read() from Conn while configuration is missing authentication method") + } +} + +func TestHostKeyAlgorithms(t *testing.T) { + serverConf := &ServerConfig{ + NoClientAuth: true, + } + serverConf.AddHostKey(testSigners["rsa"]) + serverConf.AddHostKey(testSigners["ecdsa"]) + + var wg sync.WaitGroup + t.Cleanup(wg.Wait) + connect := func(clientConf *ClientConfig, want string) { + var alg string + clientConf.HostKeyCallback = func(h string, a net.Addr, key PublicKey) error { + alg = key.Type() + return nil + } + c1, c2, err := netPipe() + if err != nil { + t.Fatalf("netPipe: %v", err) + } + defer c1.Close() + defer c2.Close() + + wg.Add(1) + go func() { + NewServerConn(c1, serverConf) + wg.Done() + }() + _, _, _, err = NewClientConn(c2, "", clientConf) + if err != nil { + t.Fatalf("NewClientConn: %v", err) + } + if alg != want { + t.Errorf("selected key algorithm %s, want %s", alg, want) + } + } + + // By default, we get the preferred algorithm, which is ECDSA 256. + + clientConf := &ClientConfig{ + HostKeyCallback: InsecureIgnoreHostKey(), + } + connect(clientConf, KeyAlgoECDSA256) + + // Client asks for RSA explicitly. + clientConf.HostKeyAlgorithms = []string{KeyAlgoRSA} + connect(clientConf, KeyAlgoRSA) + + // Client asks for RSA-SHA2-512 explicitly. + clientConf.HostKeyAlgorithms = []string{KeyAlgoRSASHA512} + // We get back an "ssh-rsa" key but the verification happened + // with an RSA-SHA2-512 signature. + connect(clientConf, KeyAlgoRSA) + + c1, c2, err := netPipe() + if err != nil { + t.Fatalf("netPipe: %v", err) + } + defer c1.Close() + defer c2.Close() + + wg.Add(1) + go func() { + NewServerConn(c1, serverConf) + wg.Done() + }() + clientConf.HostKeyAlgorithms = []string{"nonexistent-hostkey-algo"} + _, _, _, err = NewClientConn(c2, "", clientConf) + if err == nil { + t.Fatal("succeeded connecting with unknown hostkey algorithm") + } +} + +func TestServerClientAuthCallback(t *testing.T) { + c1, c2, err := netPipe() + if err != nil { + t.Fatalf("netPipe: %v", err) + } + defer c1.Close() + defer c2.Close() + + userCh := make(chan string, 1) + + serverConf := &ServerConfig{ + NoClientAuth: true, + NoClientAuthCallback: func(conn ConnMetadata) (*Permissions, error) { + userCh <- conn.User() + return nil, nil + }, + } + const someUsername = "some-username" + + serverConf.AddHostKey(testSigners["ecdsa"]) + clientConf := &ClientConfig{ + HostKeyCallback: InsecureIgnoreHostKey(), + User: someUsername, + } + + var wg sync.WaitGroup + t.Cleanup(wg.Wait) + wg.Add(1) + go func() { + defer wg.Done() + _, chans, reqs, err := NewServerConn(c1, serverConf) + if err != nil { + t.Errorf("server handshake: %v", err) + userCh <- "error" + return + } + wg.Add(1) + go func() { + DiscardRequests(reqs) + wg.Done() + }() + for ch := range chans { + ch.Reject(Prohibited, "") + } + }() + + conn, _, _, err := NewClientConn(c2, "", clientConf) + if err != nil { + t.Fatalf("client handshake: %v", err) + return + } + conn.Close() + + got := <-userCh + if got != someUsername { + t.Errorf("username = %q; want %q", got, someUsername) + } +} diff --git a/tempfork/sshtest/ssh/ssh_gss.go b/tempfork/sshtest/ssh/ssh_gss.go new file mode 100644 index 000000000..24bd7c8e8 --- /dev/null +++ b/tempfork/sshtest/ssh/ssh_gss.go @@ -0,0 +1,139 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "encoding/asn1" + "errors" +) + +var krb5OID []byte + +func init() { + krb5OID, _ = asn1.Marshal(krb5Mesh) +} + +// GSSAPIClient provides the API to plug-in GSSAPI authentication for client logins. +type GSSAPIClient interface { + // InitSecContext initiates the establishment of a security context for GSS-API between the + // ssh client and ssh server. Initially the token parameter should be specified as nil. + // The routine may return a outputToken which should be transferred to + // the ssh server, where the ssh server will present it to + // AcceptSecContext. If no token need be sent, InitSecContext will indicate this by setting + // needContinue to false. To complete the context + // establishment, one or more reply tokens may be required from the ssh + // server;if so, InitSecContext will return a needContinue which is true. + // In this case, InitSecContext should be called again when the + // reply token is received from the ssh server, passing the reply + // token to InitSecContext via the token parameters. + // See RFC 2743 section 2.2.1 and RFC 4462 section 3.4. + InitSecContext(target string, token []byte, isGSSDelegCreds bool) (outputToken []byte, needContinue bool, err error) + // GetMIC generates a cryptographic MIC for the SSH2 message, and places + // the MIC in a token for transfer to the ssh server. + // The contents of the MIC field are obtained by calling GSS_GetMIC() + // over the following, using the GSS-API context that was just + // established: + // string session identifier + // byte SSH_MSG_USERAUTH_REQUEST + // string user name + // string service + // string "gssapi-with-mic" + // See RFC 2743 section 2.3.1 and RFC 4462 3.5. + GetMIC(micFiled []byte) ([]byte, error) + // Whenever possible, it should be possible for + // DeleteSecContext() calls to be successfully processed even + // if other calls cannot succeed, thereby enabling context-related + // resources to be released. + // In addition to deleting established security contexts, + // gss_delete_sec_context must also be able to delete "half-built" + // security contexts resulting from an incomplete sequence of + // InitSecContext()/AcceptSecContext() calls. + // See RFC 2743 section 2.2.3. + DeleteSecContext() error +} + +// GSSAPIServer provides the API to plug in GSSAPI authentication for server logins. +type GSSAPIServer interface { + // AcceptSecContext allows a remotely initiated security context between the application + // and a remote peer to be established by the ssh client. The routine may return a + // outputToken which should be transferred to the ssh client, + // where the ssh client will present it to InitSecContext. + // If no token need be sent, AcceptSecContext will indicate this + // by setting the needContinue to false. To + // complete the context establishment, one or more reply tokens may be + // required from the ssh client. if so, AcceptSecContext + // will return a needContinue which is true, in which case it + // should be called again when the reply token is received from the ssh + // client, passing the token to AcceptSecContext via the + // token parameters. + // The srcName return value is the authenticated username. + // See RFC 2743 section 2.2.2 and RFC 4462 section 3.4. + AcceptSecContext(token []byte) (outputToken []byte, srcName string, needContinue bool, err error) + // VerifyMIC verifies that a cryptographic MIC, contained in the token parameter, + // fits the supplied message is received from the ssh client. + // See RFC 2743 section 2.3.2. + VerifyMIC(micField []byte, micToken []byte) error + // Whenever possible, it should be possible for + // DeleteSecContext() calls to be successfully processed even + // if other calls cannot succeed, thereby enabling context-related + // resources to be released. + // In addition to deleting established security contexts, + // gss_delete_sec_context must also be able to delete "half-built" + // security contexts resulting from an incomplete sequence of + // InitSecContext()/AcceptSecContext() calls. + // See RFC 2743 section 2.2.3. + DeleteSecContext() error +} + +var ( + // OpenSSH supports Kerberos V5 mechanism only for GSS-API authentication, + // so we also support the krb5 mechanism only. + // See RFC 1964 section 1. + krb5Mesh = asn1.ObjectIdentifier{1, 2, 840, 113554, 1, 2, 2} +) + +// The GSS-API authentication method is initiated when the client sends an SSH_MSG_USERAUTH_REQUEST +// See RFC 4462 section 3.2. +type userAuthRequestGSSAPI struct { + N uint32 + OIDS []asn1.ObjectIdentifier +} + +func parseGSSAPIPayload(payload []byte) (*userAuthRequestGSSAPI, error) { + n, rest, ok := parseUint32(payload) + if !ok { + return nil, errors.New("parse uint32 failed") + } + s := &userAuthRequestGSSAPI{ + N: n, + OIDS: make([]asn1.ObjectIdentifier, n), + } + for i := 0; i < int(n); i++ { + var ( + desiredMech []byte + err error + ) + desiredMech, rest, ok = parseString(rest) + if !ok { + return nil, errors.New("parse string failed") + } + if rest, err = asn1.Unmarshal(desiredMech, &s.OIDS[i]); err != nil { + return nil, err + } + + } + return s, nil +} + +// See RFC 4462 section 3.6. +func buildMIC(sessionID string, username string, service string, authMethod string) []byte { + out := make([]byte, 0, 0) + out = appendString(out, sessionID) + out = append(out, msgUserAuthRequest) + out = appendString(out, username) + out = appendString(out, service) + out = appendString(out, authMethod) + return out +} diff --git a/tempfork/sshtest/ssh/ssh_gss_test.go b/tempfork/sshtest/ssh/ssh_gss_test.go new file mode 100644 index 000000000..39a111288 --- /dev/null +++ b/tempfork/sshtest/ssh/ssh_gss_test.go @@ -0,0 +1,109 @@ +package ssh + +import ( + "fmt" + "testing" +) + +func TestParseGSSAPIPayload(t *testing.T) { + payload := []byte{0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x0b, 0x06, 0x09, + 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x12, 0x01, 0x02, 0x02} + res, err := parseGSSAPIPayload(payload) + if err != nil { + t.Fatal(err) + } + if ok := res.OIDS[0].Equal(krb5Mesh); !ok { + t.Fatalf("got %v, want %v", res, krb5Mesh) + } +} + +func TestBuildMIC(t *testing.T) { + sessionID := []byte{134, 180, 134, 194, 62, 145, 171, 82, 119, 149, 254, 196, 125, 173, 177, 145, 187, 85, 53, + 183, 44, 150, 219, 129, 166, 195, 19, 33, 209, 246, 175, 121} + username := "testuser" + service := "ssh-connection" + authMethod := "gssapi-with-mic" + expected := []byte{0, 0, 0, 32, 134, 180, 134, 194, 62, 145, 171, 82, 119, 149, 254, 196, 125, 173, 177, 145, 187, 85, 53, 183, 44, 150, 219, 129, 166, 195, 19, 33, 209, 246, 175, 121, 50, 0, 0, 0, 8, 116, 101, 115, 116, 117, 115, 101, 114, 0, 0, 0, 14, 115, 115, 104, 45, 99, 111, 110, 110, 101, 99, 116, 105, 111, 110, 0, 0, 0, 15, 103, 115, 115, 97, 112, 105, 45, 119, 105, 116, 104, 45, 109, 105, 99} + result := buildMIC(string(sessionID), username, service, authMethod) + if string(result) != string(expected) { + t.Fatalf("buildMic: got %v, want %v", result, expected) + } +} + +type exchange struct { + outToken string + expectedToken string +} + +type FakeClient struct { + exchanges []*exchange + round int + mic []byte + maxRound int +} + +func (f *FakeClient) InitSecContext(target string, token []byte, isGSSDelegCreds bool) (outputToken []byte, needContinue bool, err error) { + if token == nil { + if f.exchanges[f.round].expectedToken != "" { + err = fmt.Errorf("got empty token, want %q", f.exchanges[f.round].expectedToken) + } else { + outputToken = []byte(f.exchanges[f.round].outToken) + } + } else { + if string(token) != string(f.exchanges[f.round].expectedToken) { + err = fmt.Errorf("got %q, want token %q", token, f.exchanges[f.round].expectedToken) + } else { + outputToken = []byte(f.exchanges[f.round].outToken) + } + } + f.round++ + needContinue = f.round < f.maxRound + return +} + +func (f *FakeClient) GetMIC(micField []byte) ([]byte, error) { + return f.mic, nil +} + +func (f *FakeClient) DeleteSecContext() error { + return nil +} + +type FakeServer struct { + exchanges []*exchange + round int + expectedMIC []byte + srcName string + maxRound int +} + +func (f *FakeServer) AcceptSecContext(token []byte) (outputToken []byte, srcName string, needContinue bool, err error) { + if token == nil { + if f.exchanges[f.round].expectedToken != "" { + err = fmt.Errorf("got empty token, want %q", f.exchanges[f.round].expectedToken) + } else { + outputToken = []byte(f.exchanges[f.round].outToken) + } + } else { + if string(token) != string(f.exchanges[f.round].expectedToken) { + err = fmt.Errorf("got %q, want token %q", token, f.exchanges[f.round].expectedToken) + } else { + outputToken = []byte(f.exchanges[f.round].outToken) + } + } + f.round++ + needContinue = f.round < f.maxRound + srcName = f.srcName + return +} + +func (f *FakeServer) VerifyMIC(micField []byte, micToken []byte) error { + if string(micToken) != string(f.expectedMIC) { + return fmt.Errorf("got MICToken %q, want %q", micToken, f.expectedMIC) + } + return nil +} + +func (f *FakeServer) DeleteSecContext() error { + return nil +} diff --git a/tempfork/sshtest/ssh/streamlocal.go b/tempfork/sshtest/ssh/streamlocal.go new file mode 100644 index 000000000..b171b330b --- /dev/null +++ b/tempfork/sshtest/ssh/streamlocal.go @@ -0,0 +1,116 @@ +package ssh + +import ( + "errors" + "io" + "net" +) + +// streamLocalChannelOpenDirectMsg is a struct used for SSH_MSG_CHANNEL_OPEN message +// with "direct-streamlocal@openssh.com" string. +// +// See openssh-portable/PROTOCOL, section 2.4. connection: Unix domain socket forwarding +// https://github.com/openssh/openssh-portable/blob/master/PROTOCOL#L235 +type streamLocalChannelOpenDirectMsg struct { + socketPath string + reserved0 string + reserved1 uint32 +} + +// forwardedStreamLocalPayload is a struct used for SSH_MSG_CHANNEL_OPEN message +// with "forwarded-streamlocal@openssh.com" string. +type forwardedStreamLocalPayload struct { + SocketPath string + Reserved0 string +} + +// streamLocalChannelForwardMsg is a struct used for SSH2_MSG_GLOBAL_REQUEST message +// with "streamlocal-forward@openssh.com"/"cancel-streamlocal-forward@openssh.com" string. +type streamLocalChannelForwardMsg struct { + socketPath string +} + +// ListenUnix is similar to ListenTCP but uses a Unix domain socket. +func (c *Client) ListenUnix(socketPath string) (net.Listener, error) { + c.handleForwardsOnce.Do(c.handleForwards) + m := streamLocalChannelForwardMsg{ + socketPath, + } + // send message + ok, _, err := c.SendRequest("streamlocal-forward@openssh.com", true, Marshal(&m)) + if err != nil { + return nil, err + } + if !ok { + return nil, errors.New("ssh: streamlocal-forward@openssh.com request denied by peer") + } + ch := c.forwards.add(&net.UnixAddr{Name: socketPath, Net: "unix"}) + + return &unixListener{socketPath, c, ch}, nil +} + +func (c *Client) dialStreamLocal(socketPath string) (Channel, error) { + msg := streamLocalChannelOpenDirectMsg{ + socketPath: socketPath, + } + ch, in, err := c.OpenChannel("direct-streamlocal@openssh.com", Marshal(&msg)) + if err != nil { + return nil, err + } + go DiscardRequests(in) + return ch, err +} + +type unixListener struct { + socketPath string + + conn *Client + in <-chan forward +} + +// Accept waits for and returns the next connection to the listener. +func (l *unixListener) Accept() (net.Conn, error) { + s, ok := <-l.in + if !ok { + return nil, io.EOF + } + ch, incoming, err := s.newCh.Accept() + if err != nil { + return nil, err + } + go DiscardRequests(incoming) + + return &chanConn{ + Channel: ch, + laddr: &net.UnixAddr{ + Name: l.socketPath, + Net: "unix", + }, + raddr: &net.UnixAddr{ + Name: "@", + Net: "unix", + }, + }, nil +} + +// Close closes the listener. +func (l *unixListener) Close() error { + // this also closes the listener. + l.conn.forwards.remove(&net.UnixAddr{Name: l.socketPath, Net: "unix"}) + m := streamLocalChannelForwardMsg{ + l.socketPath, + } + ok, _, err := l.conn.SendRequest("cancel-streamlocal-forward@openssh.com", true, Marshal(&m)) + if err == nil && !ok { + err = errors.New("ssh: cancel-streamlocal-forward@openssh.com failed") + } + return err +} + +// Addr returns the listener's network address. +func (l *unixListener) Addr() net.Addr { + return &net.UnixAddr{ + Name: l.socketPath, + Net: "unix", + } +} diff --git a/tempfork/sshtest/ssh/tcpip.go b/tempfork/sshtest/ssh/tcpip.go new file mode 100644 index 000000000..ef5059a11 --- /dev/null +++ b/tempfork/sshtest/ssh/tcpip.go @@ -0,0 +1,509 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "context" + "errors" + "fmt" + "io" + "math/rand" + "net" + "strconv" + "strings" + "sync" + "time" +) + +// Listen requests the remote peer open a listening socket on +// addr. Incoming connections will be available by calling Accept on +// the returned net.Listener. The listener must be serviced, or the +// SSH connection may hang. +// N must be "tcp", "tcp4", "tcp6", or "unix". +func (c *Client) Listen(n, addr string) (net.Listener, error) { + switch n { + case "tcp", "tcp4", "tcp6": + laddr, err := net.ResolveTCPAddr(n, addr) + if err != nil { + return nil, err + } + return c.ListenTCP(laddr) + case "unix": + return c.ListenUnix(addr) + default: + return nil, fmt.Errorf("ssh: unsupported protocol: %s", n) + } +} + +// Automatic port allocation is broken with OpenSSH before 6.0. See +// also https://bugzilla.mindrot.org/show_bug.cgi?id=2017. In +// particular, OpenSSH 5.9 sends a channelOpenMsg with port number 0, +// rather than the actual port number. This means you can never open +// two different listeners with auto allocated ports. We work around +// this by trying explicit ports until we succeed. + +const openSSHPrefix = "OpenSSH_" + +var portRandomizer = rand.New(rand.NewSource(time.Now().UnixNano())) + +// isBrokenOpenSSHVersion returns true if the given version string +// specifies a version of OpenSSH that is known to have a bug in port +// forwarding. +func isBrokenOpenSSHVersion(versionStr string) bool { + i := strings.Index(versionStr, openSSHPrefix) + if i < 0 { + return false + } + i += len(openSSHPrefix) + j := i + for ; j < len(versionStr); j++ { + if versionStr[j] < '0' || versionStr[j] > '9' { + break + } + } + version, _ := strconv.Atoi(versionStr[i:j]) + return version < 6 +} + +// autoPortListenWorkaround simulates automatic port allocation by +// trying random ports repeatedly. +func (c *Client) autoPortListenWorkaround(laddr *net.TCPAddr) (net.Listener, error) { + var sshListener net.Listener + var err error + const tries = 10 + for i := 0; i < tries; i++ { + addr := *laddr + addr.Port = 1024 + portRandomizer.Intn(60000) + sshListener, err = c.ListenTCP(&addr) + if err == nil { + laddr.Port = addr.Port + return sshListener, err + } + } + return nil, fmt.Errorf("ssh: listen on random port failed after %d tries: %v", tries, err) +} + +// RFC 4254 7.1 +type channelForwardMsg struct { + addr string + rport uint32 +} + +// handleForwards starts goroutines handling forwarded connections. +// It's called on first use by (*Client).ListenTCP to not launch +// goroutines until needed. +func (c *Client) handleForwards() { + go c.forwards.handleChannels(c.HandleChannelOpen("forwarded-tcpip")) + go c.forwards.handleChannels(c.HandleChannelOpen("forwarded-streamlocal@openssh.com")) +} + +// ListenTCP requests the remote peer open a listening socket +// on laddr. Incoming connections will be available by calling +// Accept on the returned net.Listener. +func (c *Client) ListenTCP(laddr *net.TCPAddr) (net.Listener, error) { + c.handleForwardsOnce.Do(c.handleForwards) + if laddr.Port == 0 && isBrokenOpenSSHVersion(string(c.ServerVersion())) { + return c.autoPortListenWorkaround(laddr) + } + + m := channelForwardMsg{ + laddr.IP.String(), + uint32(laddr.Port), + } + // send message + ok, resp, err := c.SendRequest("tcpip-forward", true, Marshal(&m)) + if err != nil { + return nil, err + } + if !ok { + return nil, errors.New("ssh: tcpip-forward request denied by peer") + } + + // If the original port was 0, then the remote side will + // supply a real port number in the response. + if laddr.Port == 0 { + var p struct { + Port uint32 + } + if err := Unmarshal(resp, &p); err != nil { + return nil, err + } + laddr.Port = int(p.Port) + } + + // Register this forward, using the port number we obtained. + ch := c.forwards.add(laddr) + + return &tcpListener{laddr, c, ch}, nil +} + +// forwardList stores a mapping between remote +// forward requests and the tcpListeners. +type forwardList struct { + sync.Mutex + entries []forwardEntry +} + +// forwardEntry represents an established mapping of a laddr on a +// remote ssh server to a channel connected to a tcpListener. +type forwardEntry struct { + laddr net.Addr + c chan forward +} + +// forward represents an incoming forwarded tcpip connection. The +// arguments to add/remove/lookup should be address as specified in +// the original forward-request. +type forward struct { + newCh NewChannel // the ssh client channel underlying this forward + raddr net.Addr // the raddr of the incoming connection +} + +func (l *forwardList) add(addr net.Addr) chan forward { + l.Lock() + defer l.Unlock() + f := forwardEntry{ + laddr: addr, + c: make(chan forward, 1), + } + l.entries = append(l.entries, f) + return f.c +} + +// See RFC 4254, section 7.2 +type forwardedTCPPayload struct { + Addr string + Port uint32 + OriginAddr string + OriginPort uint32 +} + +// parseTCPAddr parses the originating address from the remote into a *net.TCPAddr. +func parseTCPAddr(addr string, port uint32) (*net.TCPAddr, error) { + if port == 0 || port > 65535 { + return nil, fmt.Errorf("ssh: port number out of range: %d", port) + } + ip := net.ParseIP(string(addr)) + if ip == nil { + return nil, fmt.Errorf("ssh: cannot parse IP address %q", addr) + } + return &net.TCPAddr{IP: ip, Port: int(port)}, nil +} + +func (l *forwardList) handleChannels(in <-chan NewChannel) { + for ch := range in { + var ( + laddr net.Addr + raddr net.Addr + err error + ) + switch channelType := ch.ChannelType(); channelType { + case "forwarded-tcpip": + var payload forwardedTCPPayload + if err = Unmarshal(ch.ExtraData(), &payload); err != nil { + ch.Reject(ConnectionFailed, "could not parse forwarded-tcpip payload: "+err.Error()) + continue + } + + // RFC 4254 section 7.2 specifies that incoming + // addresses should list the address, in string + // format. It is implied that this should be an IP + // address, as it would be impossible to connect to it + // otherwise. + laddr, err = parseTCPAddr(payload.Addr, payload.Port) + if err != nil { + ch.Reject(ConnectionFailed, err.Error()) + continue + } + raddr, err = parseTCPAddr(payload.OriginAddr, payload.OriginPort) + if err != nil { + ch.Reject(ConnectionFailed, err.Error()) + continue + } + + case "forwarded-streamlocal@openssh.com": + var payload forwardedStreamLocalPayload + if err = Unmarshal(ch.ExtraData(), &payload); err != nil { + ch.Reject(ConnectionFailed, "could not parse forwarded-streamlocal@openssh.com payload: "+err.Error()) + continue + } + laddr = &net.UnixAddr{ + Name: payload.SocketPath, + Net: "unix", + } + raddr = &net.UnixAddr{ + Name: "@", + Net: "unix", + } + default: + panic(fmt.Errorf("ssh: unknown channel type %s", channelType)) + } + if ok := l.forward(laddr, raddr, ch); !ok { + // Section 7.2, implementations MUST reject spurious incoming + // connections. + ch.Reject(Prohibited, "no forward for address") + continue + } + + } +} + +// remove removes the forward entry, and the channel feeding its +// listener. +func (l *forwardList) remove(addr net.Addr) { + l.Lock() + defer l.Unlock() + for i, f := range l.entries { + if addr.Network() == f.laddr.Network() && addr.String() == f.laddr.String() { + l.entries = append(l.entries[:i], l.entries[i+1:]...) + close(f.c) + return + } + } +} + +// closeAll closes and clears all forwards. +func (l *forwardList) closeAll() { + l.Lock() + defer l.Unlock() + for _, f := range l.entries { + close(f.c) + } + l.entries = nil +} + +func (l *forwardList) forward(laddr, raddr net.Addr, ch NewChannel) bool { + l.Lock() + defer l.Unlock() + for _, f := range l.entries { + if laddr.Network() == f.laddr.Network() && laddr.String() == f.laddr.String() { + f.c <- forward{newCh: ch, raddr: raddr} + return true + } + } + return false +} + +type tcpListener struct { + laddr *net.TCPAddr + + conn *Client + in <-chan forward +} + +// Accept waits for and returns the next connection to the listener. +func (l *tcpListener) Accept() (net.Conn, error) { + s, ok := <-l.in + if !ok { + return nil, io.EOF + } + ch, incoming, err := s.newCh.Accept() + if err != nil { + return nil, err + } + go DiscardRequests(incoming) + + return &chanConn{ + Channel: ch, + laddr: l.laddr, + raddr: s.raddr, + }, nil +} + +// Close closes the listener. +func (l *tcpListener) Close() error { + m := channelForwardMsg{ + l.laddr.IP.String(), + uint32(l.laddr.Port), + } + + // this also closes the listener. + l.conn.forwards.remove(l.laddr) + ok, _, err := l.conn.SendRequest("cancel-tcpip-forward", true, Marshal(&m)) + if err == nil && !ok { + err = errors.New("ssh: cancel-tcpip-forward failed") + } + return err +} + +// Addr returns the listener's network address. +func (l *tcpListener) Addr() net.Addr { + return l.laddr +} + +// DialContext initiates a connection to the addr from the remote host. +// +// The provided Context must be non-nil. If the context expires before the +// connection is complete, an error is returned. Once successfully connected, +// any expiration of the context will not affect the connection. +// +// See func Dial for additional information. +func (c *Client) DialContext(ctx context.Context, n, addr string) (net.Conn, error) { + if err := ctx.Err(); err != nil { + return nil, err + } + type connErr struct { + conn net.Conn + err error + } + ch := make(chan connErr) + go func() { + conn, err := c.Dial(n, addr) + select { + case ch <- connErr{conn, err}: + case <-ctx.Done(): + if conn != nil { + conn.Close() + } + } + }() + select { + case res := <-ch: + return res.conn, res.err + case <-ctx.Done(): + return nil, ctx.Err() + } +} + +// Dial initiates a connection to the addr from the remote host. +// The resulting connection has a zero LocalAddr() and RemoteAddr(). +func (c *Client) Dial(n, addr string) (net.Conn, error) { + var ch Channel + switch n { + case "tcp", "tcp4", "tcp6": + // Parse the address into host and numeric port. + host, portString, err := net.SplitHostPort(addr) + if err != nil { + return nil, err + } + port, err := strconv.ParseUint(portString, 10, 16) + if err != nil { + return nil, err + } + ch, err = c.dial(net.IPv4zero.String(), 0, host, int(port)) + if err != nil { + return nil, err + } + // Use a zero address for local and remote address. + zeroAddr := &net.TCPAddr{ + IP: net.IPv4zero, + Port: 0, + } + return &chanConn{ + Channel: ch, + laddr: zeroAddr, + raddr: zeroAddr, + }, nil + case "unix": + var err error + ch, err = c.dialStreamLocal(addr) + if err != nil { + return nil, err + } + return &chanConn{ + Channel: ch, + laddr: &net.UnixAddr{ + Name: "@", + Net: "unix", + }, + raddr: &net.UnixAddr{ + Name: addr, + Net: "unix", + }, + }, nil + default: + return nil, fmt.Errorf("ssh: unsupported protocol: %s", n) + } +} + +// DialTCP connects to the remote address raddr on the network net, +// which must be "tcp", "tcp4", or "tcp6". If laddr is not nil, it is used +// as the local address for the connection. +func (c *Client) DialTCP(n string, laddr, raddr *net.TCPAddr) (net.Conn, error) { + if laddr == nil { + laddr = &net.TCPAddr{ + IP: net.IPv4zero, + Port: 0, + } + } + ch, err := c.dial(laddr.IP.String(), laddr.Port, raddr.IP.String(), raddr.Port) + if err != nil { + return nil, err + } + return &chanConn{ + Channel: ch, + laddr: laddr, + raddr: raddr, + }, nil +} + +// RFC 4254 7.2 +type channelOpenDirectMsg struct { + raddr string + rport uint32 + laddr string + lport uint32 +} + +func (c *Client) dial(laddr string, lport int, raddr string, rport int) (Channel, error) { + msg := channelOpenDirectMsg{ + raddr: raddr, + rport: uint32(rport), + laddr: laddr, + lport: uint32(lport), + } + ch, in, err := c.OpenChannel("direct-tcpip", Marshal(&msg)) + if err != nil { + return nil, err + } + go DiscardRequests(in) + return ch, err +} + +type tcpChan struct { + Channel // the backing channel +} + +// chanConn fulfills the net.Conn interface without +// the tcpChan having to hold laddr or raddr directly. +type chanConn struct { + Channel + laddr, raddr net.Addr +} + +// LocalAddr returns the local network address. +func (t *chanConn) LocalAddr() net.Addr { + return t.laddr +} + +// RemoteAddr returns the remote network address. +func (t *chanConn) RemoteAddr() net.Addr { + return t.raddr +} + +// SetDeadline sets the read and write deadlines associated +// with the connection. +func (t *chanConn) SetDeadline(deadline time.Time) error { + if err := t.SetReadDeadline(deadline); err != nil { + return err + } + return t.SetWriteDeadline(deadline) +} + +// SetReadDeadline sets the read deadline. +// A zero value for t means Read will not time out. +// After the deadline, the error from Read will implement net.Error +// with Timeout() == true. +func (t *chanConn) SetReadDeadline(deadline time.Time) error { + // for compatibility with previous version, + // the error message contains "tcpChan" + return errors.New("ssh: tcpChan: deadline not supported") +} + +// SetWriteDeadline exists to satisfy the net.Conn interface +// but is not implemented by this type. It always returns an error. +func (t *chanConn) SetWriteDeadline(deadline time.Time) error { + return errors.New("ssh: tcpChan: deadline not supported") +} diff --git a/tempfork/sshtest/ssh/tcpip_test.go b/tempfork/sshtest/ssh/tcpip_test.go new file mode 100644 index 000000000..4d8511472 --- /dev/null +++ b/tempfork/sshtest/ssh/tcpip_test.go @@ -0,0 +1,53 @@ +// Copyright 2014 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "context" + "net" + "testing" + "time" +) + +func TestAutoPortListenBroken(t *testing.T) { + broken := "SSH-2.0-OpenSSH_5.9hh11" + works := "SSH-2.0-OpenSSH_6.1" + if !isBrokenOpenSSHVersion(broken) { + t.Errorf("version %q not marked as broken", broken) + } + if isBrokenOpenSSHVersion(works) { + t.Errorf("version %q marked as broken", works) + } +} + +func TestClientImplementsDialContext(t *testing.T) { + type ContextDialer interface { + DialContext(context.Context, string, string) (net.Conn, error) + } + // Belt and suspenders assertion, since package net does not + // declare a ContextDialer type. + var _ ContextDialer = &net.Dialer{} + var _ ContextDialer = &Client{} +} + +func TestClientDialContextWithCancel(t *testing.T) { + c := &Client{} + ctx, cancel := context.WithCancel(context.Background()) + cancel() + _, err := c.DialContext(ctx, "tcp", "localhost:1000") + if err != context.Canceled { + t.Errorf("DialContext: got nil error, expected %v", context.Canceled) + } +} + +func TestClientDialContextWithDeadline(t *testing.T) { + c := &Client{} + ctx, cancel := context.WithDeadline(context.Background(), time.Now()) + defer cancel() + _, err := c.DialContext(ctx, "tcp", "localhost:1000") + if err != context.DeadlineExceeded { + t.Errorf("DialContext: got nil error, expected %v", context.DeadlineExceeded) + } +} diff --git a/tempfork/sshtest/ssh/testdata_test.go b/tempfork/sshtest/ssh/testdata_test.go new file mode 100644 index 000000000..2da8c79dc --- /dev/null +++ b/tempfork/sshtest/ssh/testdata_test.go @@ -0,0 +1,63 @@ +// Copyright 2014 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// IMPLEMENTATION NOTE: To avoid a package loop, this file is in three places: +// ssh/, ssh/agent, and ssh/test/. It should be kept in sync across all three +// instances. + +package ssh + +import ( + "crypto/rand" + "fmt" + + "golang.org/x/crypto/ssh/testdata" +) + +var ( + testPrivateKeys map[string]interface{} + testSigners map[string]Signer + testPublicKeys map[string]PublicKey +) + +func init() { + var err error + + n := len(testdata.PEMBytes) + testPrivateKeys = make(map[string]interface{}, n) + testSigners = make(map[string]Signer, n) + testPublicKeys = make(map[string]PublicKey, n) + for t, k := range testdata.PEMBytes { + testPrivateKeys[t], err = ParseRawPrivateKey(k) + if err != nil { + panic(fmt.Sprintf("Unable to parse test key %s: %v", t, err)) + } + testSigners[t], err = NewSignerFromKey(testPrivateKeys[t]) + if err != nil { + panic(fmt.Sprintf("Unable to create signer for test key %s: %v", t, err)) + } + testPublicKeys[t] = testSigners[t].PublicKey() + } + + // Create a cert and sign it for use in tests. + testCert := &Certificate{ + Nonce: []byte{}, // To pass reflect.DeepEqual after marshal & parse, this must be non-nil + ValidPrincipals: []string{"gopher1", "gopher2"}, // increases test coverage + ValidAfter: 0, // unix epoch + ValidBefore: CertTimeInfinity, // The end of currently representable time. + Reserved: []byte{}, // To pass reflect.DeepEqual after marshal & parse, this must be non-nil + Key: testPublicKeys["ecdsa"], + SignatureKey: testPublicKeys["rsa"], + Permissions: Permissions{ + CriticalOptions: map[string]string{}, + Extensions: map[string]string{}, + }, + } + testCert.SignCert(rand.Reader, testSigners["rsa"]) + testPrivateKeys["cert"] = testPrivateKeys["ecdsa"] + testSigners["cert"], err = NewCertSigner(testCert, testSigners["ecdsa"]) + if err != nil { + panic(fmt.Sprintf("Unable to create certificate signer: %v", err)) + } +} diff --git a/tempfork/sshtest/ssh/transport.go b/tempfork/sshtest/ssh/transport.go new file mode 100644 index 000000000..0424d2d37 --- /dev/null +++ b/tempfork/sshtest/ssh/transport.go @@ -0,0 +1,380 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "bufio" + "bytes" + "errors" + "io" + "log" +) + +// debugTransport if set, will print packet types as they go over the +// wire. No message decoding is done, to minimize the impact on timing. +const debugTransport = false + +const ( + gcm128CipherID = "aes128-gcm@openssh.com" + gcm256CipherID = "aes256-gcm@openssh.com" + aes128cbcID = "aes128-cbc" + tripledescbcID = "3des-cbc" +) + +// packetConn represents a transport that implements packet based +// operations. +type packetConn interface { + // Encrypt and send a packet of data to the remote peer. + writePacket(packet []byte) error + + // Read a packet from the connection. The read is blocking, + // i.e. if error is nil, then the returned byte slice is + // always non-empty. + readPacket() ([]byte, error) + + // Close closes the write-side of the connection. + Close() error +} + +// transport is the keyingTransport that implements the SSH packet +// protocol. +type transport struct { + reader connectionState + writer connectionState + + bufReader *bufio.Reader + bufWriter *bufio.Writer + rand io.Reader + isClient bool + io.Closer + + strictMode bool + initialKEXDone bool +} + +// packetCipher represents a combination of SSH encryption/MAC +// protocol. A single instance should be used for one direction only. +type packetCipher interface { + // writeCipherPacket encrypts the packet and writes it to w. The + // contents of the packet are generally scrambled. + writeCipherPacket(seqnum uint32, w io.Writer, rand io.Reader, packet []byte) error + + // readCipherPacket reads and decrypts a packet of data. The + // returned packet may be overwritten by future calls of + // readPacket. + readCipherPacket(seqnum uint32, r io.Reader) ([]byte, error) +} + +// connectionState represents one side (read or write) of the +// connection. This is necessary because each direction has its own +// keys, and can even have its own algorithms +type connectionState struct { + packetCipher + seqNum uint32 + dir direction + pendingKeyChange chan packetCipher +} + +func (t *transport) setStrictMode() error { + if t.reader.seqNum != 1 { + return errors.New("ssh: sequence number != 1 when strict KEX mode requested") + } + t.strictMode = true + return nil +} + +func (t *transport) setInitialKEXDone() { + t.initialKEXDone = true +} + +// prepareKeyChange sets up key material for a keychange. The key changes in +// both directions are triggered by reading and writing a msgNewKey packet +// respectively. +func (t *transport) prepareKeyChange(algs *algorithms, kexResult *kexResult) error { + ciph, err := newPacketCipher(t.reader.dir, algs.r, kexResult) + if err != nil { + return err + } + t.reader.pendingKeyChange <- ciph + + ciph, err = newPacketCipher(t.writer.dir, algs.w, kexResult) + if err != nil { + return err + } + t.writer.pendingKeyChange <- ciph + + return nil +} + +func (t *transport) printPacket(p []byte, write bool) { + if len(p) == 0 { + return + } + who := "server" + if t.isClient { + who = "client" + } + what := "read" + if write { + what = "write" + } + + log.Println(what, who, p[0]) +} + +// Read and decrypt next packet. +func (t *transport) readPacket() (p []byte, err error) { + for { + p, err = t.reader.readPacket(t.bufReader, t.strictMode) + if err != nil { + break + } + // in strict mode we pass through DEBUG and IGNORE packets only during the initial KEX + if len(p) == 0 || (t.strictMode && !t.initialKEXDone) || (p[0] != msgIgnore && p[0] != msgDebug) { + break + } + } + if debugTransport { + t.printPacket(p, false) + } + + return p, err +} + +func (s *connectionState) readPacket(r *bufio.Reader, strictMode bool) ([]byte, error) { + packet, err := s.packetCipher.readCipherPacket(s.seqNum, r) + s.seqNum++ + if err == nil && len(packet) == 0 { + err = errors.New("ssh: zero length packet") + } + + if len(packet) > 0 { + switch packet[0] { + case msgNewKeys: + select { + case cipher := <-s.pendingKeyChange: + s.packetCipher = cipher + if strictMode { + s.seqNum = 0 + } + default: + return nil, errors.New("ssh: got bogus newkeys message") + } + + case msgDisconnect: + // Transform a disconnect message into an + // error. Since this is lowest level at which + // we interpret message types, doing it here + // ensures that we don't have to handle it + // elsewhere. + var msg disconnectMsg + if err := Unmarshal(packet, &msg); err != nil { + return nil, err + } + return nil, &msg + } + } + + // The packet may point to an internal buffer, so copy the + // packet out here. + fresh := make([]byte, len(packet)) + copy(fresh, packet) + + return fresh, err +} + +func (t *transport) writePacket(packet []byte) error { + if debugTransport { + t.printPacket(packet, true) + } + return t.writer.writePacket(t.bufWriter, t.rand, packet, t.strictMode) +} + +func (s *connectionState) writePacket(w *bufio.Writer, rand io.Reader, packet []byte, strictMode bool) error { + changeKeys := len(packet) > 0 && packet[0] == msgNewKeys + + err := s.packetCipher.writeCipherPacket(s.seqNum, w, rand, packet) + if err != nil { + return err + } + if err = w.Flush(); err != nil { + return err + } + s.seqNum++ + if changeKeys { + select { + case cipher := <-s.pendingKeyChange: + s.packetCipher = cipher + if strictMode { + s.seqNum = 0 + } + default: + panic("ssh: no key material for msgNewKeys") + } + } + return err +} + +func newTransport(rwc io.ReadWriteCloser, rand io.Reader, isClient bool) *transport { + t := &transport{ + bufReader: bufio.NewReader(rwc), + bufWriter: bufio.NewWriter(rwc), + rand: rand, + reader: connectionState{ + packetCipher: &streamPacketCipher{cipher: noneCipher{}}, + pendingKeyChange: make(chan packetCipher, 1), + }, + writer: connectionState{ + packetCipher: &streamPacketCipher{cipher: noneCipher{}}, + pendingKeyChange: make(chan packetCipher, 1), + }, + Closer: rwc, + } + t.isClient = isClient + + if isClient { + t.reader.dir = serverKeys + t.writer.dir = clientKeys + } else { + t.reader.dir = clientKeys + t.writer.dir = serverKeys + } + + return t +} + +type direction struct { + ivTag []byte + keyTag []byte + macKeyTag []byte +} + +var ( + serverKeys = direction{[]byte{'B'}, []byte{'D'}, []byte{'F'}} + clientKeys = direction{[]byte{'A'}, []byte{'C'}, []byte{'E'}} +) + +// setupKeys sets the cipher and MAC keys from kex.K, kex.H and sessionId, as +// described in RFC 4253, section 6.4. direction should either be serverKeys +// (to setup server->client keys) or clientKeys (for client->server keys). +func newPacketCipher(d direction, algs directionAlgorithms, kex *kexResult) (packetCipher, error) { + cipherMode := cipherModes[algs.Cipher] + + iv := make([]byte, cipherMode.ivSize) + key := make([]byte, cipherMode.keySize) + + generateKeyMaterial(iv, d.ivTag, kex) + generateKeyMaterial(key, d.keyTag, kex) + + var macKey []byte + if !aeadCiphers[algs.Cipher] { + macMode := macModes[algs.MAC] + macKey = make([]byte, macMode.keySize) + generateKeyMaterial(macKey, d.macKeyTag, kex) + } + + return cipherModes[algs.Cipher].create(key, iv, macKey, algs) +} + +// generateKeyMaterial fills out with key material generated from tag, K, H +// and sessionId, as specified in RFC 4253, section 7.2. +func generateKeyMaterial(out, tag []byte, r *kexResult) { + var digestsSoFar []byte + + h := r.Hash.New() + for len(out) > 0 { + h.Reset() + h.Write(r.K) + h.Write(r.H) + + if len(digestsSoFar) == 0 { + h.Write(tag) + h.Write(r.SessionID) + } else { + h.Write(digestsSoFar) + } + + digest := h.Sum(nil) + n := copy(out, digest) + out = out[n:] + if len(out) > 0 { + digestsSoFar = append(digestsSoFar, digest...) + } + } +} + +const packageVersion = "SSH-2.0-Go" + +// Sends and receives a version line. The versionLine string should +// be US ASCII, start with "SSH-2.0-", and should not include a +// newline. exchangeVersions returns the other side's version line. +func exchangeVersions(rw io.ReadWriter, versionLine []byte) (them []byte, err error) { + // Contrary to the RFC, we do not ignore lines that don't + // start with "SSH-2.0-" to make the library usable with + // nonconforming servers. + for _, c := range versionLine { + // The spec disallows non US-ASCII chars, and + // specifically forbids null chars. + if c < 32 { + return nil, errors.New("ssh: junk character in version line") + } + } + if _, err = rw.Write(append(versionLine, '\r', '\n')); err != nil { + return + } + + them, err = readVersion(rw) + return them, err +} + +// maxVersionStringBytes is the maximum number of bytes that we'll +// accept as a version string. RFC 4253 section 4.2 limits this at 255 +// chars +const maxVersionStringBytes = 255 + +// Read version string as specified by RFC 4253, section 4.2. +func readVersion(r io.Reader) ([]byte, error) { + versionString := make([]byte, 0, 64) + var ok bool + var buf [1]byte + + for length := 0; length < maxVersionStringBytes; length++ { + _, err := io.ReadFull(r, buf[:]) + if err != nil { + return nil, err + } + // The RFC says that the version should be terminated with \r\n + // but several SSH servers actually only send a \n. + if buf[0] == '\n' { + if !bytes.HasPrefix(versionString, []byte("SSH-")) { + // RFC 4253 says we need to ignore all version string lines + // except the one containing the SSH version (provided that + // all the lines do not exceed 255 bytes in total). + versionString = versionString[:0] + continue + } + ok = true + break + } + + // non ASCII chars are disallowed, but we are lenient, + // since Go doesn't use null-terminated strings. + + // The RFC allows a comment after a space, however, + // all of it (version and comments) goes into the + // session hash. + versionString = append(versionString, buf[0]) + } + + if !ok { + return nil, errors.New("ssh: overflow reading version string") + } + + // There might be a '\r' on the end which we should remove. + if len(versionString) > 0 && versionString[len(versionString)-1] == '\r' { + versionString = versionString[:len(versionString)-1] + } + return versionString, nil +} diff --git a/tempfork/sshtest/ssh/transport_test.go b/tempfork/sshtest/ssh/transport_test.go new file mode 100644 index 000000000..8445e1e56 --- /dev/null +++ b/tempfork/sshtest/ssh/transport_test.go @@ -0,0 +1,113 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "bytes" + "crypto/rand" + "encoding/binary" + "strings" + "testing" +) + +func TestReadVersion(t *testing.T) { + longVersion := strings.Repeat("SSH-2.0-bla", 50)[:253] + multiLineVersion := strings.Repeat("ignored\r\n", 20) + "SSH-2.0-bla\r\n" + cases := map[string]string{ + "SSH-2.0-bla\r\n": "SSH-2.0-bla", + "SSH-2.0-bla\n": "SSH-2.0-bla", + multiLineVersion: "SSH-2.0-bla", + longVersion + "\r\n": longVersion, + } + + for in, want := range cases { + result, err := readVersion(bytes.NewBufferString(in)) + if err != nil { + t.Errorf("readVersion(%q): %s", in, err) + } + got := string(result) + if got != want { + t.Errorf("got %q, want %q", got, want) + } + } +} + +func TestReadVersionError(t *testing.T) { + longVersion := strings.Repeat("SSH-2.0-bla", 50)[:253] + multiLineVersion := strings.Repeat("ignored\r\n", 50) + "SSH-2.0-bla\r\n" + cases := []string{ + longVersion + "too-long\r\n", + multiLineVersion, + } + for _, in := range cases { + if _, err := readVersion(bytes.NewBufferString(in)); err == nil { + t.Errorf("readVersion(%q) should have failed", in) + } + } +} + +func TestExchangeVersionsBasic(t *testing.T) { + v := "SSH-2.0-bla" + buf := bytes.NewBufferString(v + "\r\n") + them, err := exchangeVersions(buf, []byte("xyz")) + if err != nil { + t.Errorf("exchangeVersions: %v", err) + } + + if want := "SSH-2.0-bla"; string(them) != want { + t.Errorf("got %q want %q for our version", them, want) + } +} + +func TestExchangeVersions(t *testing.T) { + cases := []string{ + "not\x000allowed", + "not allowed\x01\r\n", + } + for _, c := range cases { + buf := bytes.NewBufferString("SSH-2.0-bla\r\n") + if _, err := exchangeVersions(buf, []byte(c)); err == nil { + t.Errorf("exchangeVersions(%q): should have failed", c) + } + } +} + +type closerBuffer struct { + bytes.Buffer +} + +func (b *closerBuffer) Close() error { + return nil +} + +func TestTransportMaxPacketWrite(t *testing.T) { + buf := &closerBuffer{} + tr := newTransport(buf, rand.Reader, true) + huge := make([]byte, maxPacket+1) + err := tr.writePacket(huge) + if err == nil { + t.Errorf("transport accepted write for a huge packet.") + } +} + +func TestTransportMaxPacketReader(t *testing.T) { + var header [5]byte + huge := make([]byte, maxPacket+128) + binary.BigEndian.PutUint32(header[0:], uint32(len(huge))) + // padding. + header[4] = 0 + + buf := &closerBuffer{} + buf.Write(header[:]) + buf.Write(huge) + + tr := newTransport(buf, rand.Reader, true) + _, err := tr.readPacket() + if err == nil { + t.Errorf("transport succeeded reading huge packet.") + } else if !strings.Contains(err.Error(), "large") { + t.Errorf("got %q, should mention %q", err.Error(), "large") + } +}