diff options
Diffstat (limited to 'vendor/golang.org/x/crypto/ssh/server.go')
| -rw-r--r-- | vendor/golang.org/x/crypto/ssh/server.go | 46 |
1 files changed, 39 insertions, 7 deletions
diff --git a/vendor/golang.org/x/crypto/ssh/server.go b/vendor/golang.org/x/crypto/ssh/server.go index 6a58e1208..70045bdfd 100644 --- a/vendor/golang.org/x/crypto/ssh/server.go +++ b/vendor/golang.org/x/crypto/ssh/server.go @@ -120,7 +120,7 @@ type ServerConfig struct { } // AddHostKey adds a private key as a host key. If an existing host -// key exists with the same algorithm, it is overwritten. Each server +// key exists with the same public key format, it is replaced. Each server // config must have at least one host key. func (s *ServerConfig) AddHostKey(key Signer) { for i, k := range s.hostKeys { @@ -212,9 +212,10 @@ func NewServerConn(c net.Conn, config *ServerConfig) (*ServerConn, <-chan NewCha } // signAndMarshal signs the data with the appropriate algorithm, -// and serializes the result in SSH wire format. -func signAndMarshal(k Signer, rand io.Reader, data []byte) ([]byte, error) { - sig, err := k.Sign(rand, data) +// and serializes the result in SSH wire format. algo is the negotiate +// algorithm and may be a certificate type. +func signAndMarshal(k AlgorithmSigner, rand io.Reader, data []byte, algo string) ([]byte, error) { + sig, err := k.SignWithAlgorithm(rand, data, underlyingAlgo(algo)) if err != nil { return nil, err } @@ -284,7 +285,7 @@ func (s *connection) serverHandshake(config *ServerConfig) (*Permissions, error) func isAcceptableAlgo(algo string) bool { switch algo { - case SigAlgoRSA, SigAlgoRSASHA2256, SigAlgoRSASHA2512, KeyAlgoDSA, KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521, KeyAlgoSKECDSA256, KeyAlgoED25519, KeyAlgoSKED25519, + case KeyAlgoRSA, KeyAlgoRSASHA256, KeyAlgoRSASHA512, KeyAlgoDSA, KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521, KeyAlgoSKECDSA256, KeyAlgoED25519, KeyAlgoSKED25519, CertAlgoRSAv01, CertAlgoDSAv01, CertAlgoECDSA256v01, CertAlgoECDSA384v01, CertAlgoECDSA521v01, CertAlgoSKECDSA256v01, CertAlgoED25519v01, CertAlgoSKED25519v01: return true } @@ -553,6 +554,7 @@ userAuthLoop: if !ok || len(payload) > 0 { return nil, parseError(msgUserAuthRequest) } + // Ensure the public key algo and signature algo // are supported. Compare the private key // algorithm name that corresponds to algo with @@ -562,7 +564,12 @@ userAuthLoop: authErr = fmt.Errorf("ssh: algorithm %q not accepted", sig.Format) break } - signedData := buildDataSignedForAuth(sessionID, userAuthReq, algoBytes, pubKeyData) + if underlyingAlgo(algo) != sig.Format { + authErr = fmt.Errorf("ssh: signature %q not compatible with selected algorithm %q", sig.Format, algo) + break + } + + signedData := buildDataSignedForAuth(sessionID, userAuthReq, algo, pubKeyData) if err := pubKey.Verify(signedData, sig); err != nil { return nil, err @@ -633,6 +640,30 @@ userAuthLoop: } authFailures++ + if config.MaxAuthTries > 0 && authFailures >= config.MaxAuthTries { + // If we have hit the max attempts, don't bother sending the + // final SSH_MSG_USERAUTH_FAILURE message, since there are + // no more authentication methods which can be attempted, + // and this message may cause the client to re-attempt + // authentication while we send the disconnect message. + // Continue, and trigger the disconnect at the start of + // the loop. + // + // The SSH specification is somewhat confusing about this, + // RFC 4252 Section 5.1 requires each authentication failure + // be responded to with a respective SSH_MSG_USERAUTH_FAILURE + // message, but Section 4 says the server should disconnect + // after some number of attempts, but it isn't explicit which + // message should take precedence (i.e. should there be a failure + // message than a disconnect message, or if we are going to + // disconnect, should we only send that message.) + // + // Either way, OpenSSH disconnects immediately after the last + // failed authnetication attempt, and given they are typically + // considered the golden implementation it seems reasonable + // to match that behavior. + continue + } var failureMsg userAuthFailureMsg if config.PasswordCallback != nil { @@ -670,7 +701,7 @@ type sshClientKeyboardInteractive struct { *connection } -func (c *sshClientKeyboardInteractive) Challenge(user, instruction string, questions []string, echos []bool) (answers []string, err error) { +func (c *sshClientKeyboardInteractive) Challenge(name, instruction string, questions []string, echos []bool) (answers []string, err error) { if len(questions) != len(echos) { return nil, errors.New("ssh: echos and questions must have equal length") } @@ -682,6 +713,7 @@ func (c *sshClientKeyboardInteractive) Challenge(user, instruction string, quest } if err := c.transport.writePacket(Marshal(&userAuthInfoRequestMsg{ + Name: name, Instruction: instruction, NumPrompts: uint32(len(questions)), Prompts: prompts, |