plumbing: transport/ssh, add support for custom proxy URLs

Signed-off-by: Sanskar Jaiswal <jaiswalsanskar078@gmail.com>

5 files changed, 287 insertions, 14 deletions

diff --git a/plumbing/transport/ssh/common.go b/plumbing/transport/ssh/common.go
index e06958a..6617d9b 100644
--- a/plumbing/transport/ssh/common.go
+++ b/plumbing/transport/ssh/common.go
@@ -4,6 +4,7 @@ package ssh
 import (
 	"context"
 	"fmt"
+	"net"
 	"reflect"
 	"strconv"
 	"strings"
@@ -139,7 +140,7 @@ func (c *command) connect() error {
 
 	overrideConfig(c.config, config)
 
-	c.client, err = dial("tcp", hostWithPort, config)
+	c.client, err = dial("tcp", hostWithPort, c.endpoint.Proxy, config)
 	if err != nil {
 		return err
 	}
@@ -154,7 +155,7 @@ func (c *command) connect() error {
 	return nil
 }
 
-func dial(network, addr string, config *ssh.ClientConfig) (*ssh.Client, error) {
+func dial(network, addr string, proxyOpts transport.ProxyOptions, config *ssh.ClientConfig) (*ssh.Client, error) {
 	var (
 		ctx    = context.Background()
 		cancel context.CancelFunc
@@ -166,10 +167,33 @@ func dial(network, addr string, config *ssh.ClientConfig) (*ssh.Client, error) {
 	}
 	defer cancel()
 
-	conn, err := proxy.Dial(ctx, network, addr)
+	var conn net.Conn
+	var err error
+
+	if proxyOpts.URL != "" {
+		proxyUrl, err := proxyOpts.FullURL()
+		if err != nil {
+			return nil, err
+		}
+		dialer, err := proxy.FromURL(proxyUrl, proxy.Direct)
+		if err != nil {
+			return nil, err
+		}
+
+		// Try to use a ContextDialer, but fall back to a Dialer if that goes south.
+		ctxDialer, ok := dialer.(proxy.ContextDialer)
+		if !ok {
+			return nil, fmt.Errorf("expected ssh proxy dialer to be of type %s; got %s",
+				reflect.TypeOf(ctxDialer), reflect.TypeOf(dialer))
+		}
+		conn, err = ctxDialer.DialContext(ctx, "tcp", addr)
+	} else {
+		conn, err = proxy.Dial(ctx, network, addr)
+	}
 	if err != nil {
 		return nil, err
 	}
+
 	c, chans, reqs, err := ssh.NewClientConn(conn, addr, config)
 	if err != nil {
 		return nil, err
diff --git a/plumbing/transport/ssh/internal/test/proxy_test.go b/plumbing/transport/ssh/internal/test/proxy_test.go
new file mode 100644
index 0000000..8baac2b
--- /dev/null
+++ b/plumbing/transport/ssh/internal/test/proxy_test.go
@@ -0,0 +1,113 @@
+package test
+
+import (
+	"context"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"net"
+	"os"
+	"path/filepath"
+	"sync/atomic"
+	"testing"
+
+	"github.com/armon/go-socks5"
+	"github.com/gliderlabs/ssh"
+	"github.com/go-git/go-git/v5/plumbing/transport"
+	ggssh "github.com/go-git/go-git/v5/plumbing/transport/ssh"
+
+	fixtures "github.com/go-git/go-git-fixtures/v4"
+	stdssh "golang.org/x/crypto/ssh"
+	. "gopkg.in/check.v1"
+)
+
+func Test(t *testing.T) { TestingT(t) }
+
+type ProxyEnvSuite struct {
+	fixtures.Suite
+	port int
+	base string
+}
+
+var _ = Suite(&ProxyEnvSuite{})
+
+var socksProxiedRequests int32
+
+// This test tests proxy support via an env var, i.e. `ALL_PROXY`.
+// Its located in a separate package because golang caches the value
+// of proxy env vars leading to misleading/unexpected test results.
+func (s *ProxyEnvSuite) TestCommand(c *C) {
+	socksListener, err := net.Listen("tcp", "localhost:0")
+	c.Assert(err, IsNil)
+
+	socksServer, err := socks5.New(&socks5.Config{
+		Rules: TestProxyRule{},
+	})
+	c.Assert(err, IsNil)
+	go func() {
+		socksServer.Serve(socksListener)
+	}()
+	socksProxyAddr := fmt.Sprintf("socks5://localhost:%d", socksListener.Addr().(*net.TCPAddr).Port)
+	os.Setenv("ALL_PROXY", socksProxyAddr)
+	defer os.Unsetenv("ALL_PROXY")
+
+	sshListener, err := net.Listen("tcp", "localhost:0")
+	c.Assert(err, IsNil)
+	sshServer := &ssh.Server{Handler: HandlerSSH}
+	go func() {
+		log.Fatal(sshServer.Serve(sshListener))
+	}()
+
+	s.port = sshListener.Addr().(*net.TCPAddr).Port
+	s.base, err = ioutil.TempDir(os.TempDir(), fmt.Sprintf("go-git-ssh-%d", s.port))
+	c.Assert(err, IsNil)
+
+	ggssh.DefaultAuthBuilder = func(user string) (ggssh.AuthMethod, error) {
+		return &ggssh.Password{User: user}, nil
+	}
+
+	ep := s.prepareRepository(c, fixtures.Basic().One(), "basic.git")
+	c.Assert(err, IsNil)
+
+	client := ggssh.NewClient(&stdssh.ClientConfig{
+		HostKeyCallback: stdssh.InsecureIgnoreHostKey(),
+	})
+	r, err := client.NewUploadPackSession(ep, nil)
+	c.Assert(err, IsNil)
+	defer func() { c.Assert(r.Close(), IsNil) }()
+
+	info, err := r.AdvertisedReferences()
+	c.Assert(err, IsNil)
+	c.Assert(info, NotNil)
+	proxyUsed := atomic.LoadInt32(&socksProxiedRequests) > 0
+	c.Assert(proxyUsed, Equals, true)
+}
+
+func (s *ProxyEnvSuite) prepareRepository(c *C, f *fixtures.Fixture, name string) *transport.Endpoint {
+	fs := f.DotGit()
+
+	err := fixtures.EnsureIsBare(fs)
+	c.Assert(err, IsNil)
+
+	path := filepath.Join(s.base, name)
+	err = os.Rename(fs.Root(), path)
+	c.Assert(err, IsNil)
+
+	return s.newEndpoint(c, name)
+}
+
+func (s *ProxyEnvSuite) newEndpoint(c *C, name string) *transport.Endpoint {
+	ep, err := transport.NewEndpoint(fmt.Sprintf(
+		"ssh://git@localhost:%d/%s/%s", s.port, filepath.ToSlash(s.base), name,
+	))
+
+	c.Assert(err, IsNil)
+	return ep
+}
+
+type TestProxyRule struct{}
+
+func (dr TestProxyRule) Allow(ctx context.Context, req *socks5.Request) (context.Context, bool) {
+	atomic.AddInt32(&socksProxiedRequests, 1)
+	return ctx, true
+}
diff --git a/plumbing/transport/ssh/internal/test/test_utils.go b/plumbing/transport/ssh/internal/test/test_utils.go
new file mode 100644
index 0000000..c3797b1
--- /dev/null
+++ b/plumbing/transport/ssh/internal/test/test_utils.go
@@ -0,0 +1,83 @@
+package test
+
+import (
+	"fmt"
+	"io"
+	"os/exec"
+	"runtime"
+	"strings"
+	"sync"
+
+	"github.com/gliderlabs/ssh"
+)
+
+func HandlerSSH(s ssh.Session) {
+	cmd, stdin, stderr, stdout, err := buildCommand(s.Command())
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+
+	if err := cmd.Start(); err != nil {
+		fmt.Println(err)
+		return
+	}
+
+	go func() {
+		defer stdin.Close()
+		io.Copy(stdin, s)
+	}()
+
+	var wg sync.WaitGroup
+	wg.Add(2)
+
+	go func() {
+		defer wg.Done()
+		io.Copy(s.Stderr(), stderr)
+	}()
+
+	go func() {
+		defer wg.Done()
+		io.Copy(s, stdout)
+	}()
+
+	wg.Wait()
+
+	if err := cmd.Wait(); err != nil {
+		return
+	}
+
+}
+
+func buildCommand(c []string) (cmd *exec.Cmd, stdin io.WriteCloser, stderr, stdout io.ReadCloser, err error) {
+	if len(c) != 2 {
+		err = fmt.Errorf("invalid command")
+		return
+	}
+
+	// fix for Windows environments
+	var path string
+	if runtime.GOOS == "windows" {
+		path = strings.Replace(c[1], "/C:/", "C:/", 1)
+	} else {
+		path = c[1]
+	}
+
+	cmd = exec.Command(c[0], path)
+	stdout, err = cmd.StdoutPipe()
+	if err != nil {
+		return
+	}
+
+	stdin, err = cmd.StdinPipe()
+	if err != nil {
+		return
+	}
+
+	stderr, err = cmd.StderrPipe()
+	if err != nil {
+		return
+	}
+
+	return
+}
diff --git a/plumbing/transport/ssh/proxy_test.go b/plumbing/transport/ssh/proxy_test.go
index 3caf1ff..2fab851 100644
--- a/plumbing/transport/ssh/proxy_test.go
+++ b/plumbing/transport/ssh/proxy_test.go
@@ -1,36 +1,88 @@
 package ssh
 
 import (
+	"context"
 	"fmt"
+	"io/ioutil"
 	"log"
 	"net"
 	"os"
+	"sync/atomic"
 
 	"github.com/armon/go-socks5"
+	"github.com/gliderlabs/ssh"
+	"github.com/go-git/go-git/v5/plumbing/transport"
+	"github.com/go-git/go-git/v5/plumbing/transport/ssh/internal/test"
+
+	fixtures "github.com/go-git/go-git-fixtures/v4"
+	stdssh "golang.org/x/crypto/ssh"
 	. "gopkg.in/check.v1"
 )
 
 type ProxySuite struct {
-	UploadPackSuite
+	u UploadPackSuite
+	fixtures.Suite
 }
 
 var _ = Suite(&ProxySuite{})
 
-func (s *ProxySuite) SetUpSuite(c *C) {
-	s.UploadPackSuite.SetUpSuite(c)
+var socksProxiedRequests int32
 
-	l, err := net.Listen("tcp", "localhost:0")
+func (s *ProxySuite) TestCommand(c *C) {
+	socksListener, err := net.Listen("tcp", "localhost:0")
 	c.Assert(err, IsNil)
 
-	server, err := socks5.New(&socks5.Config{})
+	socksServer, err := socks5.New(&socks5.Config{
+		AuthMethods: []socks5.Authenticator{socks5.UserPassAuthenticator{
+			Credentials: socks5.StaticCredentials{
+				"user": "pass",
+			},
+		}},
+		Rules: TestProxyRule{},
+	})
 	c.Assert(err, IsNil)
+	go func() {
+		socksServer.Serve(socksListener)
+	}()
+	socksProxyAddr := fmt.Sprintf("socks5://localhost:%d", socksListener.Addr().(*net.TCPAddr).Port)
 
-	port := l.Addr().(*net.TCPAddr).Port
-
-	err = os.Setenv("ALL_PROXY", fmt.Sprintf("socks5://localhost:%d", port))
+	sshListener, err := net.Listen("tcp", "localhost:0")
 	c.Assert(err, IsNil)
-
+	sshServer := &ssh.Server{Handler: test.HandlerSSH}
 	go func() {
-		log.Fatal(server.Serve(l))
+		log.Fatal(sshServer.Serve(sshListener))
 	}()
+
+	s.u.port = sshListener.Addr().(*net.TCPAddr).Port
+	s.u.base, err = ioutil.TempDir(os.TempDir(), fmt.Sprintf("go-git-ssh-%d", s.u.port))
+	c.Assert(err, IsNil)
+
+	DefaultAuthBuilder = func(user string) (AuthMethod, error) {
+		return &Password{User: user}, nil
+	}
+
+	ep := s.u.prepareRepository(c, fixtures.Basic().One(), "basic.git")
+	c.Assert(err, IsNil)
+	ep.Proxy = transport.ProxyOptions{
+		URL:      socksProxyAddr,
+		Username: "user",
+		Password: "pass",
+	}
+
+	runner := runner{
+		config: &stdssh.ClientConfig{
+			HostKeyCallback: stdssh.InsecureIgnoreHostKey(),
+		},
+	}
+	_, err = runner.Command(transport.UploadPackServiceName, ep, nil)
+	c.Assert(err, IsNil)
+	proxyUsed := atomic.LoadInt32(&socksProxiedRequests) > 0
+	c.Assert(proxyUsed, Equals, true)
+}
+
+type TestProxyRule struct{}
+
+func (dr TestProxyRule) Allow(ctx context.Context, req *socks5.Request) (context.Context, bool) {
+	atomic.AddInt32(&socksProxiedRequests, 1)
+	return ctx, true
 }
diff --git a/plumbing/transport/ssh/upload_pack_test.go b/plumbing/transport/ssh/upload_pack_test.go
index f172fee..fafff48 100644
--- a/plumbing/transport/ssh/upload_pack_test.go
+++ b/plumbing/transport/ssh/upload_pack_test.go
@@ -14,6 +14,7 @@ import (
 	"sync"
 
 	"github.com/go-git/go-git/v5/plumbing/transport"
+	testutils "github.com/go-git/go-git/v5/plumbing/transport/ssh/internal/test"
 	"github.com/go-git/go-git/v5/plumbing/transport/test"
 
 	"github.com/gliderlabs/ssh"
@@ -57,7 +58,7 @@ func (s *UploadPackSuite) SetUpSuite(c *C) {
 	s.UploadPackSuite.EmptyEndpoint = s.prepareRepository(c, fixtures.ByTag("empty").One(), "empty.git")
 	s.UploadPackSuite.NonExistentEndpoint = s.newEndpoint(c, "non-existent.git")
 
-	server := &ssh.Server{Handler: handlerSSH}
+	server := &ssh.Server{Handler: testutils.HandlerSSH}
 	for _, opt := range s.opts {
 		opt(server)
 	}