auth: Support for EdDSA JWT algorithm

The golang-jwt library supports this already, so supporting it is just a
matter of wiring things up.

Signed-off-by: Tom Wieczorek <twieczorek@mirantis.com>

server/auth/jwt.go

@@ -17,6 +17,7 @@ package auth
 import (
 	"context"
 	"crypto/ecdsa"
+	"crypto/ed25519"
 	"crypto/rsa"
 	"errors"
 	"time"
@@ -54,6 +55,8 @@ func (t *tokenJWT) info(ctx context.Context, token string, rev uint64) (*AuthInf
 			return &k.PublicKey, nil
 		case *ecdsa.PrivateKey:
 			return &k.PublicKey, nil
+		case ed25519.PrivateKey:
+			return k.Public(), nil
 		default:
 			return t.key, nil
 		}
@@ -161,6 +164,10 @@ func newTokenProviderJWT(lg *zap.Logger, optMap map[string]string) (*tokenJWT, e
 		if _, ok := t.key.(*ecdsa.PublicKey); ok {
 			t.verifyOnly = true
 		}
+	case *jwt.SigningMethodEd25519:
+		if _, ok := t.key.(ed25519.PublicKey); ok {
+			t.verifyOnly = true
+		}
 	case *jwt.SigningMethodRSA, *jwt.SigningMethodRSAPSS:
 		if _, ok := t.key.(*rsa.PublicKey); ok {
 			t.verifyOnly = true

server/auth/jwt_test.go

@@ -31,6 +31,9 @@ const (
 
 	jwtECPubKey  = "../../tests/fixtures/server-ecdsa.crt"
 	jwtECPrivKey = "../../tests/fixtures/server-ecdsa.key.insecure"
+
+	jwtEdPubKey  = "../../tests/fixtures/ed25519-public-key.pem"
+	jwtEdPrivKey = "../../tests/fixtures/ed25519-private-key.pem"
 )
 
 func TestJWTInfo(t *testing.T) {
@@ -63,6 +66,15 @@ func TestJWTInfo(t *testing.T) {
 			"priv-key":    jwtECPrivKey,
 			"sign-method": "ES256",
 		},
+		"Ed25519-priv": {
+			"priv-key":    jwtEdPrivKey,
+			"sign-method": "EdDSA",
+		},
+		"Ed25519": {
+			"pub-key":     jwtEdPubKey,
+			"priv-key":    jwtEdPrivKey,
+			"sign-method": "EdDSA",
+		},
 		"HMAC": {
 			"priv-key":    jwtECPrivKey, // any file, raw bytes used as shared secret
 			"sign-method": "HS256",

server/auth/options.go

@@ -15,7 +15,9 @@
 package auth
 
 import (
+	"crypto"
 	"crypto/ecdsa"
+	"crypto/ed25519"
 	"crypto/rsa"
 	"fmt"
 	"os"
@@ -100,6 +102,8 @@ func (opts *jwtOptions) Key() (interface{}, error) {
 		return opts.rsaKey()
 	case *jwt.SigningMethodECDSA:
 		return opts.ecKey()
+	case *jwt.SigningMethodEd25519:
+		return opts.edKey()
 	case *jwt.SigningMethodHMAC:
 		return opts.hmacKey()
 	default:
@@ -189,3 +193,45 @@ func (opts *jwtOptions) ecKey() (interface{}, error) {
 
 	return priv, nil
 }
+
+func (opts *jwtOptions) edKey() (interface{}, error) {
+	var (
+		priv ed25519.PrivateKey
+		pub  ed25519.PublicKey
+		err  error
+	)
+
+	if len(opts.PrivateKey) > 0 {
+		var privKey crypto.PrivateKey
+		privKey, err = jwt.ParseEdPrivateKeyFromPEM(opts.PrivateKey)
+		if err != nil {
+			return nil, err
+		}
+		priv = privKey.(ed25519.PrivateKey)
+	}
+
+	if len(opts.PublicKey) > 0 {
+		var pubKey crypto.PublicKey
+		pubKey, err = jwt.ParseEdPublicKeyFromPEM(opts.PublicKey)
+		if err != nil {
+			return nil, err
+		}
+		pub = pubKey.(ed25519.PublicKey)
+	}
+
+	if priv == nil {
+		if pub == nil {
+			// Neither key given
+			return nil, ErrMissingKey
+		}
+		// Public key only, can verify tokens
+		return pub, nil
+	}
+
+	// both keys provided, make sure they match
+	if pub != nil && !pub.Equal(priv.Public()) {
+		return nil, ErrKeyMismatch
+	}
+
+	return priv, nil
+}

tests/fixtures/ed25519-private-key.pem

@@ -0,0 +1,3 @@
+-----BEGIN PRIVATE KEY-----
+MC4CAQAwBQYDK2VwBCIEIAtiwQ7KeS1I0otY9gw1Ox4av/zQ+wvs/8AIaTkawQ73
+-----END PRIVATE KEY-----

tests/fixtures/ed25519-public-key.pem

@@ -0,0 +1,3 @@
+-----BEGIN PUBLIC KEY-----
+MCowBQYDK2VwAyEAuOUxC8Bbn1KqYctlim/MHaP5JrtmeK5xcs+9w506btA=
+-----END PUBLIC KEY-----