transport: ssh, NewPublicKeys helper

plumbing/transport/ssh/auth_method.go

@@ -3,6 +3,7 @@ package ssh
 import (
 	"errors"
 	"fmt"
+	"io/ioutil"
 	"net"
 	"os"
 	"os/user"
@@ -13,6 +14,8 @@ import (
 	"golang.org/x/crypto/ssh/agent"
 )
 
+const DefaultUsername = "git"
+
 var ErrEmptySSHAgentAddr = errors.New("SSH_AUTH_SOCK env variable is required")
 
 // AuthMethod is the interface all auth methods for the ssh client
@@ -102,14 +105,35 @@ func (a *PasswordCallback) clientConfig() *ssh.ClientConfig {
 	}
 }
 
-// PublicKeys implements AuthMethod by using the given
-// key pairs.
+// PublicKeys implements AuthMethod by using the given key pairs.
 type PublicKeys struct {
 	User   string
 	Signer ssh.Signer
 	baseAuthMethod
 }
 
+// NewPublicKeys returns a PublicKeys from a PEM encoded private key. It
+// supports RSA (PKCS#1), DSA (OpenSSL), and ECDSA private keys.
+func NewPublicKeys(user string, pemBytes []byte) (AuthMethod, error) {
+	signer, err := ssh.ParsePrivateKey(pemBytes)
+	if err != nil {
+		return nil, err
+	}
+
+	return &PublicKeys{User: user, Signer: signer}, nil
+}
+
+// NewPublicKeysFromFile returns a PublicKeys from a file containing a PEM
+// encoded private key.
+func NewPublicKeysFromFile(user string, pemFile string) (AuthMethod, error) {
+	bytes, err := ioutil.ReadFile(pemFile)
+	if err != nil {
+		return nil, err
+	}
+
+	return NewPublicKeys(user, bytes)
+}
+
 func (a *PublicKeys) Name() string {
 	return PublicKeysName
 }
@@ -133,28 +157,12 @@ type PublicKeysCallback struct {
 	baseAuthMethod
 }
 
-func (a *PublicKeysCallback) Name() string {
-	return PublicKeysCallbackName
-}
-
-func (a *PublicKeysCallback) String() string {
-	return fmt.Sprintf("user: %s, name: %s", a.User, a.Name())
-}
-
-func (a *PublicKeysCallback) clientConfig() *ssh.ClientConfig {
-	return &ssh.ClientConfig{
-		User: a.User,
-		Auth: []ssh.AuthMethod{ssh.PublicKeysCallback(a.Callback)},
-	}
-}
-
-const DefaultSSHUsername = "git"
-
-// NewSSHAgentAuth opens a pipe with the SSH agent and uses the pipe
-// as the implementer of the public key callback function.
-func NewSSHAgentAuth(user string) (*PublicKeysCallback, error) {
+// NewSSHAgentAuth returns a PublicKeysCallback based on a SSH agent, it opens
+// a pipe with the SSH agent and uses the pipe as the implementer of the public
+// key callback function.
+func NewSSHAgentAuth(user string) (AuthMethod, error) {
 	if user == "" {
-		user = DefaultSSHUsername
+		user = DefaultUsername
 	}
 
 	sshAgentAddr := os.Getenv("SSH_AUTH_SOCK")
@@ -173,6 +181,21 @@ func NewSSHAgentAuth(user string) (*PublicKeysCallback, error) {
 	}, nil
 }
 
+func (a *PublicKeysCallback) Name() string {
+	return PublicKeysCallbackName
+}
+
+func (a *PublicKeysCallback) String() string {
+	return fmt.Sprintf("user: %s, name: %s", a.User, a.Name())
+}
+
+func (a *PublicKeysCallback) clientConfig() *ssh.ClientConfig {
+	return &ssh.ClientConfig{
+		User: a.User,
+		Auth: []ssh.AuthMethod{ssh.PublicKeysCallback(a.Callback)},
+	}
+}
+
 // NewKnownHostsCallback returns ssh.HostKeyCallback based on a file based on a
 // know_hosts file. http://man.openbsd.org/sshd#SSH_KNOWN_HOSTS_FILE_FORMAT
 //

plumbing/transport/ssh/auth_method_test.go

@@ -2,8 +2,11 @@ package ssh
 
 import (
 	"fmt"
+	"io/ioutil"
 	"os"
 
+	"golang.org/x/crypto/ssh/testdata"
+
 	. "gopkg.in/check.v1"
 )
 
@@ -104,3 +107,22 @@ func (s *SuiteCommon) TestNewSSHAgentAuth(c *C) {
 	c.Assert(k, IsNil)
 	c.Assert(err, Equals, ErrEmptySSHAgentAddr)
 }
+
+func (*SuiteCommon) TestNewPublicKeys(c *C) {
+	auth, err := NewPublicKeys("foo", testdata.PEMBytes["rsa"])
+	c.Assert(err, IsNil)
+	c.Assert(auth, NotNil)
+}
+
+func (*SuiteCommon) TestNewPublicKeysFromFile(c *C) {
+	f, err := ioutil.TempFile("", "ssh-test")
+	c.Assert(err, IsNil)
+	_, err = f.Write(testdata.PEMBytes["rsa"])
+	c.Assert(err, IsNil)
+	c.Assert(f.Close(), IsNil)
+	defer os.RemoveAll(f.Name())
+
+	auth, err := NewPublicKeysFromFile("foo", f.Name())
+	c.Assert(err, IsNil)
+	c.Assert(auth, NotNil)
+}