mirrors/tailscale
1
0
Fork 0
Code Issues Pull Requests Projects Wiki Activity

net/tshttpproxy: fix incorrect type in Windows implementation, switch to mkwinsyscall, fix memory leak

Browse Source 
The definition of winHTTPProxyInfo was using the wrong type (uint16 vs uint32)
for its first field. I fixed that type.

Furthermore, any UTF16 strings returned in that structure must be explicitly
freed. I added code to do this.

Finally, since this is the second time I've seen type safety errors in this code,
I switched the native API calls over to use wrappers generated by mkwinsyscall.
I know that would not have helped prevent the previous two problems, but every
bit helps IMHO.

Updates https://github.com/tailscale/tailscale/issues/4811

Signed-off-by: Aaron Klotz <aaron@tailscale.com>
This commit is contained in:
Aaron Klotz
2022-07-27 13:47:28 -06:00
parent 446d03e108
commit 4dbdb19c26
3 changed files with 133 additions and 44 deletions
Download Patch File Download Diff File Expand all files Collapse all files

84
net/tshttpproxy/tshttpproxy_windows.go
View File

@ -26,13 +26,6 @@ import (
"tailscale.com/util/cmpver"
)
var (
winHTTP = windows.NewLazySystemDLL("winhttp.dll")
httpOpenProc = winHTTP.NewProc("WinHttpOpen")
closeHandleProc = winHTTP.NewProc("WinHttpCloseHandle")
getProxyForUrlProc = winHTTP.NewProc("WinHttpGetProxyForUrl")
)
func init() {
sysProxyFromEnv = proxyFromWinHTTPOrCache
sysAuthHeader = sysAuthHeaderWindows
@ -116,7 +109,7 @@ func proxyFromWinHTTP(ctx context.Context, urlStr string) (proxy *url.URL, err e
runtime.LockOSThread()
defer runtime.UnlockOSThread()
whi, err := winHTTPOpen()
whi, err := httpOpen()
if err != nil {
proxyErrorf("winhttp: Open: %v", err)
return nil, err
@ -178,38 +171,25 @@ func getAccessFlag() uint32 {
return flag
}
func winHTTPOpen() (winHTTPInternet, error) {
if err := httpOpenProc.Find(); err != nil {
return 0, err
}
r, _, err := httpOpenProc.Call(
uintptr(unsafe.Pointer(userAgent)),
uintptr(getAccessFlag()),
0, /* WINHTTP_NO_PROXY_NAME */
0, /* WINHTTP_NO_PROXY_BYPASS */
0)
if r == 0 {
return 0, err
}
return winHTTPInternet(r), nil
func httpOpen() (winHTTPInternet, error) {
return winHTTPOpen(
userAgent,
getAccessFlag(),
nil, /* WINHTTP_NO_PROXY_NAME */
nil, /* WINHTTP_NO_PROXY_BYPASS */
0,
)
}
type winHTTPInternet windows.Handle
func (hi winHTTPInternet) Close() error {
if err := closeHandleProc.Find(); err != nil {
return err
}
r, _, err := closeHandleProc.Call(uintptr(hi))
if r == 1 {
return nil
}
return err
return winHTTPCloseHandle(hi)
}
// WINHTTP_AUTOPROXY_OPTIONS
// https://docs.microsoft.com/en-us/windows/win32/api/winhttp/ns-winhttp-winhttp_autoproxy_options
type autoProxyOptions struct {
type winHTTPAutoProxyOptions struct {
DwFlags uint32
DwAutoDetectFlags uint32
AutoConfigUrl *uint16
@ -221,30 +201,46 @@ type autoProxyOptions struct {
// WINHTTP_PROXY_INFO
// https://docs.microsoft.com/en-us/windows/win32/api/winhttp/ns-winhttp-winhttp_proxy_info
type winHTTPProxyInfo struct {
AccessType uint16
AccessType uint32
Proxy *uint16
ProxyBypass *uint16
}
var proxyForURLOpts = &autoProxyOptions{
type winHGlobal windows.Handle
func globalFreeUTF16Ptr(p *uint16) error {
return globalFree((winHGlobal)(unsafe.Pointer(p)))
}
func (pi *winHTTPProxyInfo) free() {
if pi.Proxy != nil {
globalFreeUTF16Ptr(pi.Proxy)
pi.Proxy = nil
}
if pi.ProxyBypass != nil {
globalFreeUTF16Ptr(pi.ProxyBypass)
pi.ProxyBypass = nil
}
}
var proxyForURLOpts = &winHTTPAutoProxyOptions{
DwFlags: winHTTP_AUTOPROXY_ALLOW_AUTOCONFIG | winHTTP_AUTOPROXY_AUTO_DETECT,
DwAutoDetectFlags: winHTTP_AUTO_DETECT_TYPE_DHCP, // | winHTTP_AUTO_DETECT_TYPE_DNS_A,
}
func (hi winHTTPInternet) GetProxyForURL(urlStr string) (string, error) {
if err := getProxyForUrlProc.Find(); err != nil {
var out winHTTPProxyInfo
err := winHTTPGetProxyForURL(
hi,
windows.StringToUTF16Ptr(urlStr),
proxyForURLOpts,
&out,
)
if err != nil {
return "", err
}
var out winHTTPProxyInfo
r, _, err := getProxyForUrlProc.Call(
uintptr(hi),
uintptr(unsafe.Pointer(windows.StringToUTF16Ptr(urlStr))),
uintptr(unsafe.Pointer(proxyForURLOpts)),
uintptr(unsafe.Pointer(&out)))
if r == 1 {
return windows.UTF16PtrToString(out.Proxy), nil
}
return "", err
defer out.free()
return windows.UTF16PtrToString(out.Proxy), nil
}
func sysAuthHeaderWindows(u *url.URL) (string, error) {