Update: callback for repositories

- adds a callback for ACL (to return the list of repositories for the current user)
- adds all public key data to extensions
- exposes the extensions via environment variables (GITKIT_) to the hook

README.md

@@ -208,6 +208,7 @@ Paste the following:
 ```
 Host localhost
   Port 2222
+  ForwardAgent no
 ```
 
 Now that the server is configured, we can fire it up:

go.mod

@@ -5,13 +5,15 @@ go 1.19
 require (
 	github.com/gofrs/uuid v4.0.0+incompatible
 	github.com/stretchr/testify v1.7.0
-	golang.org/x/crypto v0.0.0-20210513164829-c07d793c2f9a
+	golang.org/x/crypto v0.9.0
 	golang.org/x/exp v0.0.0-20230203172020-98cc5a0785f9
 )
 
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/kr/text v0.2.0 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
-	golang.org/x/sys v0.1.0 // indirect
-	gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c // indirect
+	golang.org/x/sys v0.8.0 // indirect
+	gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -1,21 +1,30 @@
+github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/gofrs/uuid v4.0.0+incompatible h1:1SD/1F5pU8p29ybwgQSwpQk+mwdRrXCYuPhW6m+TnJw=
 github.com/gofrs/uuid v4.0.0+incompatible/go.mod h1:b2aQJv3Z4Fp6yNu3cdSllBxTCLRxnplIgP/c0N/04lM=
+github.com/kr/pretty v0.2.1 h1:Fmg33tUaq4/8ym9TJN1x7sLJnHVwhP33CNkpYV/7rwI=
+github.com/kr/pretty v0.2.1/go.mod h1:ipq/a2n7PKx3OHsz4KJII5eveXtPO4qwEXGdVfWzfnI=
+github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
+github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
+github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
+github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
-golang.org/x/crypto v0.0.0-20210513164829-c07d793c2f9a h1:kr2P4QFmQr29mSLA43kwrOcgcReGTfbE9N577tCTuBc=
-golang.org/x/crypto v0.0.0-20210513164829-c07d793c2f9a/go.mod h1:P+XmwS30IXTQdn5tA2iutPOUgjI07+tq3H3K9MVA1s8=
+golang.org/x/crypto v0.9.0 h1:LF6fAI+IutBocDJ2OT0Q1g8plpYljMZ4+lty+dsqw3g=
+golang.org/x/crypto v0.9.0/go.mod h1:yrmDGqONDYtNj3tH8X9dzUun2m2lzPa9ngI6/RUPGR0=
 golang.org/x/exp v0.0.0-20230203172020-98cc5a0785f9 h1:frX3nT9RkKybPnjyI+yvZh6ZucTZatCCEm9D47sZ2zo=
 golang.org/x/exp v0.0.0-20230203172020-98cc5a0785f9/go.mod h1:CxIveKay+FTh1D0yPZemJVgC/95VzuuOLq5Qi4xnoYc=
-golang.org/x/sys v0.1.0 h1:kunALQeHf1/185U1i0GOB/fy1IPRDDpuoOOqRReG57U=
-golang.org/x/sys v0.1.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1 h1:v+OssWQX+hTHEmOBgwxdZxK4zHq3yOs8F9J7mk0PY8E=
-gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+golang.org/x/sys v0.8.0 h1:EBmGv8NaZBZTWvrbjNoL6HVt+IVy3QDQpJs7VRIw3tU=
+golang.org/x/sys v0.8.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/term v0.8.0 h1:n5xxQn2i3PC0yLAbjTpNT85q/Kgzcr2gIoX9OrJUols=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
+gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
+gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

ssh.go

@@ -30,9 +30,10 @@ type PublicKey struct {
 type SSH struct {
 	listener net.Listener
 
-	sshconfig           *ssh.ServerConfig
-	config              *Config
-	PublicKeyLookupFunc func(string) (*PublicKey, error)
+	sshconfig             *ssh.ServerConfig
+	config                *Config
+	PublicKeyLookupFunc   func(string) (*PublicKey, error)
+	ReposForKeyLookupFunc func(*PublicKey) ([]string, error)
 }
 
 func NewSSH(config Config) *SSH {
@@ -75,7 +76,7 @@ func execCommand(cmdname string, args ...string) (string, string, error) {
 	return string(bufOut), string(bufErr), err
 }
 
-func (s *SSH) handleConnection(keyID string, chans <-chan ssh.NewChannel) {
+func (s *SSH) handleConnection(exts map[string]string, chans <-chan ssh.NewChannel) {
 	for newChan := range chans {
 		if newChan.ChannelType() != "session" {
 			newChan.Reject(ssh.UnknownChannelType, "unknown channel type")
@@ -142,7 +143,17 @@ func (s *SSH) handleConnection(keyID string, chans <-chan ssh.NewChannel) {
 
 					cmd := exec.Command(gitcmd.Command, gitcmd.Repo)
 					cmd.Dir = s.config.Dir
-					cmd.Env = append(os.Environ(), "GITKIT_KEY="+keyID)
+
+					envVariables := os.Environ()
+					envVariables = append(envVariables, "GITKIT_CURRENT_REPOSITORY="+gitcmd.Repo)
+
+					// append data via ssh.Permissions.Extensions
+					for k, v := range exts {
+						log.Println("k=" + k + ", v=" + v)
+						envVariables = append(envVariables, "GITKIT_"+strings.ToUpper(k)+"="+v)
+					}
+					cmd.Env = envVariables
+
 					// cmd.Env = append(os.Environ(), "SSH_ORIGINAL_COMMAND="+cmdName)
 
 					stdout, err := cmd.StdoutPipe()
@@ -209,6 +220,10 @@ func (s *SSH) setup() error {
 			return fmt.Errorf("public key lookup func is not provided")
 		}
 
+		if s.ReposForKeyLookupFunc == nil {
+			log.Println("no repository callback, an authorized user may access any repositories")
+		}
+
 		config.PublicKeyCallback = func(conn ssh.ConnMetadata, key ssh.PublicKey) (*ssh.Permissions, error) {
 			pkey, err := s.PublicKeyLookupFunc(strings.TrimSpace(string(ssh.MarshalAuthorizedKey(key))))
 			if err != nil {
@@ -219,7 +234,23 @@ func (s *SSH) setup() error {
 				return nil, fmt.Errorf("auth handler did not return a key")
 			}
 
-			return &ssh.Permissions{Extensions: map[string]string{"key-id": pkey.Id}}, nil
+			var repos []string
+
+			if s.ReposForKeyLookupFunc != nil {
+				repos, err = s.ReposForKeyLookupFunc(pkey)
+				if err != nil {
+					return nil, err
+				}
+			}
+
+			return &ssh.Permissions{
+				Extensions: map[string]string{
+					"key":          pkey.Id,
+					"fingerprint":  pkey.Fingerprint,
+					"name":         pkey.Name,
+					"repositories": strings.Join(repos, ","),
+				},
+			}, nil
 		}
 	}
 
@@ -296,13 +327,13 @@ func (s *SSH) Serve() error {
 				return
 			}
 
-			keyId := ""
+			var exts map[string]string
 			if sConn.Permissions != nil {
-				keyId = sConn.Permissions.Extensions["key-id"]
+				exts = sConn.Permissions.Extensions
 			}
 
 			go ssh.DiscardRequests(reqs)
-			go s.handleConnection(keyId, chans)
+			go s.handleConnection(exts, chans)
 		}()
 	}
 }

ssh_test.go

@@ -0,0 +1,85 @@
+package gitkit_test
+
+import (
+	"errors"
+	"fmt"
+	"net"
+	"path/filepath"
+	"testing"
+
+	"github.com/sosedoff/gitkit"
+	"github.com/stretchr/testify/assert"
+	"golang.org/x/crypto/ssh"
+)
+
+func TestKeyLookupFunctionIsNeeded(t *testing.T) {
+	s := newSSH(t, t.TempDir())
+
+	err := s.Listen(":0") // random port
+	assert.Equal(t, errors.New("public key lookup func is not provided"), err)
+}
+
+func TestListener(t *testing.T) {
+	testDir := t.TempDir()
+
+	s := newSSH(t, testDir)
+	s.PublicKeyLookupFunc = func(content string) (*gitkit.PublicKey, error) {
+		return &gitkit.PublicKey{Id: "1234"}, nil
+	}
+
+	sshdConfig, err := setup(t, testDir)
+	assert.NoError(t, err)
+
+	s.SetSSHConfig(sshdConfig)
+
+	listener, err := net.Listen("tcp4", ":0")
+	assert.NoError(t, err)
+
+	s.SetListener(listener)
+	t.Logf("address: %s", listener.Addr())
+
+	go func() {
+		defer s.Stop()
+		err := s.Serve()
+		assert.NoError(t, err)
+	}()
+
+	// assert the keys are created
+	assert.FileExists(t, filepath.Join(testDir, "keys/gitkit.rsa"))
+	assert.FileExists(t, filepath.Join(testDir, "keys/gitkit.rsa.pub"))
+}
+
+func newSSH(t *testing.T, baseDir string) *gitkit.SSH {
+	t.Helper()
+
+	return gitkit.NewSSH(gitkit.Config{
+		Auth:       true,
+		AutoCreate: true,
+		KeyDir:     filepath.Join(baseDir, "keys"),
+		Dir:        filepath.Join(baseDir, "repos"),
+	})
+}
+
+// custom setup function to replicate what gitkit does to setup the ssh server,
+// but doesn't do when you supply a custom listener
+func setup(t *testing.T, dir string) (*ssh.ServerConfig, error) {
+	t.Helper()
+
+	config := &ssh.ServerConfig{
+		ServerVersion: fmt.Sprintf("SSH-2.0-gitkit %s", "testing"),
+	}
+
+	config.NoClientAuth = true
+
+	// create server key
+	k := gitkit.NewKey(filepath.Join(dir, "keys"))
+
+	err := k.CreateRSA()
+	assert.NoError(t, err)
+
+	private, err := k.GetRSA()
+	assert.NoError(t, err)
+
+	config.AddHostKey(private)
+	return config, nil
+}