diff options
Diffstat (limited to 'vendor/golang.org/x/crypto/ssh/client_auth.go')
| -rw-r--r-- | vendor/golang.org/x/crypto/ssh/client_auth.go | 121 |
1 files changed, 80 insertions, 41 deletions
diff --git a/vendor/golang.org/x/crypto/ssh/client_auth.go b/vendor/golang.org/x/crypto/ssh/client_auth.go index 3acd8d4..5f44b77 100644 --- a/vendor/golang.org/x/crypto/ssh/client_auth.go +++ b/vendor/golang.org/x/crypto/ssh/client_auth.go @@ -11,6 +11,14 @@ import ( "io" ) +type authResult int + +const ( + authFailure authResult = iota + authPartialSuccess + authSuccess +) + // clientAuthenticate authenticates with the remote server. See RFC 4252. func (c *connection) clientAuthenticate(config *ClientConfig) error { // initiate user auth session @@ -37,11 +45,12 @@ func (c *connection) clientAuthenticate(config *ClientConfig) error { if err != nil { return err } - if ok { + if ok == authSuccess { // success return nil + } else if ok == authFailure { + tried[auth.method()] = true } - tried[auth.method()] = true if methods == nil { methods = lastMethods } @@ -82,7 +91,7 @@ type AuthMethod interface { // If authentication is not successful, a []string of alternative // method names is returned. If the slice is nil, it will be ignored // and the previous set of possible methods will be reused. - auth(session []byte, user string, p packetConn, rand io.Reader) (bool, []string, error) + auth(session []byte, user string, p packetConn, rand io.Reader) (authResult, []string, error) // method returns the RFC 4252 method name. method() string @@ -91,13 +100,13 @@ type AuthMethod interface { // "none" authentication, RFC 4252 section 5.2. type noneAuth int -func (n *noneAuth) auth(session []byte, user string, c packetConn, rand io.Reader) (bool, []string, error) { +func (n *noneAuth) auth(session []byte, user string, c packetConn, rand io.Reader) (authResult, []string, error) { if err := c.writePacket(Marshal(&userAuthRequestMsg{ User: user, Service: serviceSSH, Method: "none", })); err != nil { - return false, nil, err + return authFailure, nil, err } return handleAuthResponse(c) @@ -111,7 +120,7 @@ func (n *noneAuth) method() string { // a function call, e.g. by prompting the user. type passwordCallback func() (password string, err error) -func (cb passwordCallback) auth(session []byte, user string, c packetConn, rand io.Reader) (bool, []string, error) { +func (cb passwordCallback) auth(session []byte, user string, c packetConn, rand io.Reader) (authResult, []string, error) { type passwordAuthMsg struct { User string `sshtype:"50"` Service string @@ -125,7 +134,7 @@ func (cb passwordCallback) auth(session []byte, user string, c packetConn, rand // The program may only find out that the user doesn't have a password // when prompting. if err != nil { - return false, nil, err + return authFailure, nil, err } if err := c.writePacket(Marshal(&passwordAuthMsg{ @@ -135,7 +144,7 @@ func (cb passwordCallback) auth(session []byte, user string, c packetConn, rand Reply: false, Password: pw, })); err != nil { - return false, nil, err + return authFailure, nil, err } return handleAuthResponse(c) @@ -178,7 +187,7 @@ func (cb publicKeyCallback) method() string { return "publickey" } -func (cb publicKeyCallback) auth(session []byte, user string, c packetConn, rand io.Reader) (bool, []string, error) { +func (cb publicKeyCallback) auth(session []byte, user string, c packetConn, rand io.Reader) (authResult, []string, error) { // Authentication is performed by sending an enquiry to test if a key is // acceptable to the remote. If the key is acceptable, the client will // attempt to authenticate with the valid key. If not the client will repeat @@ -186,13 +195,13 @@ func (cb publicKeyCallback) auth(session []byte, user string, c packetConn, rand signers, err := cb() if err != nil { - return false, nil, err + return authFailure, nil, err } var methods []string for _, signer := range signers { ok, err := validateKey(signer.PublicKey(), user, c) if err != nil { - return false, nil, err + return authFailure, nil, err } if !ok { continue @@ -206,7 +215,7 @@ func (cb publicKeyCallback) auth(session []byte, user string, c packetConn, rand Method: cb.method(), }, []byte(pub.Type()), pubKey)) if err != nil { - return false, nil, err + return authFailure, nil, err } // manually wrap the serialized signature in a string @@ -224,24 +233,24 @@ func (cb publicKeyCallback) auth(session []byte, user string, c packetConn, rand } p := Marshal(&msg) if err := c.writePacket(p); err != nil { - return false, nil, err + return authFailure, nil, err } - var success bool + var success authResult success, methods, err = handleAuthResponse(c) if err != nil { - return false, nil, err + return authFailure, nil, err } // If authentication succeeds or the list of available methods does not // contain the "publickey" method, do not attempt to authenticate with any // other keys. According to RFC 4252 Section 7, the latter can occur when // additional authentication methods are required. - if success || !containsMethod(methods, cb.method()) { + if success == authSuccess || !containsMethod(methods, cb.method()) { return success, methods, err } } - return false, methods, nil + return authFailure, methods, nil } func containsMethod(methods []string, method string) bool { @@ -283,7 +292,9 @@ func confirmKeyAck(key PublicKey, c packetConn) (bool, error) { } switch packet[0] { case msgUserAuthBanner: - // TODO(gpaul): add callback to present the banner to the user + if err := handleBannerResponse(c, packet); err != nil { + return false, err + } case msgUserAuthPubKeyOk: var msg userAuthPubKeyOkMsg if err := Unmarshal(packet, &msg); err != nil { @@ -316,30 +327,53 @@ func PublicKeysCallback(getSigners func() (signers []Signer, err error)) AuthMet // handleAuthResponse returns whether the preceding authentication request succeeded // along with a list of remaining authentication methods to try next and // an error if an unexpected response was received. -func handleAuthResponse(c packetConn) (bool, []string, error) { +func handleAuthResponse(c packetConn) (authResult, []string, error) { for { packet, err := c.readPacket() if err != nil { - return false, nil, err + return authFailure, nil, err } switch packet[0] { case msgUserAuthBanner: - // TODO: add callback to present the banner to the user + if err := handleBannerResponse(c, packet); err != nil { + return authFailure, nil, err + } case msgUserAuthFailure: var msg userAuthFailureMsg if err := Unmarshal(packet, &msg); err != nil { - return false, nil, err + return authFailure, nil, err + } + if msg.PartialSuccess { + return authPartialSuccess, msg.Methods, nil } - return false, msg.Methods, nil + return authFailure, msg.Methods, nil case msgUserAuthSuccess: - return true, nil, nil + return authSuccess, nil, nil default: - return false, nil, unexpectedMessageError(msgUserAuthSuccess, packet[0]) + return authFailure, nil, unexpectedMessageError(msgUserAuthSuccess, packet[0]) } } } +func handleBannerResponse(c packetConn, packet []byte) error { + var msg userAuthBannerMsg + if err := Unmarshal(packet, &msg); err != nil { + return err + } + + transport, ok := c.(*handshakeTransport) + if !ok { + return nil + } + + if transport.bannerCallback != nil { + return transport.bannerCallback(msg.Message) + } + + return nil +} + // KeyboardInteractiveChallenge should print questions, optionally // disabling echoing (e.g. for passwords), and return all the answers. // Challenge may be called multiple times in a single session. After @@ -359,7 +393,7 @@ func (cb KeyboardInteractiveChallenge) method() string { return "keyboard-interactive" } -func (cb KeyboardInteractiveChallenge) auth(session []byte, user string, c packetConn, rand io.Reader) (bool, []string, error) { +func (cb KeyboardInteractiveChallenge) auth(session []byte, user string, c packetConn, rand io.Reader) (authResult, []string, error) { type initiateMsg struct { User string `sshtype:"50"` Service string @@ -373,37 +407,42 @@ func (cb KeyboardInteractiveChallenge) auth(session []byte, user string, c packe Service: serviceSSH, Method: "keyboard-interactive", })); err != nil { - return false, nil, err + return authFailure, nil, err } for { packet, err := c.readPacket() if err != nil { - return false, nil, err + return authFailure, nil, err } // like handleAuthResponse, but with less options. switch packet[0] { case msgUserAuthBanner: - // TODO: Print banners during userauth. + if err := handleBannerResponse(c, packet); err != nil { + return authFailure, nil, err + } continue case msgUserAuthInfoRequest: // OK case msgUserAuthFailure: var msg userAuthFailureMsg if err := Unmarshal(packet, &msg); err != nil { - return false, nil, err + return authFailure, nil, err + } + if msg.PartialSuccess { + return authPartialSuccess, msg.Methods, nil } - return false, msg.Methods, nil + return authFailure, msg.Methods, nil case msgUserAuthSuccess: - return true, nil, nil + return authSuccess, nil, nil default: - return false, nil, unexpectedMessageError(msgUserAuthInfoRequest, packet[0]) + return authFailure, nil, unexpectedMessageError(msgUserAuthInfoRequest, packet[0]) } var msg userAuthInfoRequestMsg if err := Unmarshal(packet, &msg); err != nil { - return false, nil, err + return authFailure, nil, err } // Manually unpack the prompt/echo pairs. @@ -413,7 +452,7 @@ func (cb KeyboardInteractiveChallenge) auth(session []byte, user string, c packe for i := 0; i < int(msg.NumPrompts); i++ { prompt, r, ok := parseString(rest) if !ok || len(r) == 0 { - return false, nil, errors.New("ssh: prompt format error") + return authFailure, nil, errors.New("ssh: prompt format error") } prompts = append(prompts, string(prompt)) echos = append(echos, r[0] != 0) @@ -421,16 +460,16 @@ func (cb KeyboardInteractiveChallenge) auth(session []byte, user string, c packe } if len(rest) != 0 { - return false, nil, errors.New("ssh: extra data following keyboard-interactive pairs") + return authFailure, nil, errors.New("ssh: extra data following keyboard-interactive pairs") } answers, err := cb(msg.User, msg.Instruction, prompts, echos) if err != nil { - return false, nil, err + return authFailure, nil, err } if len(answers) != len(prompts) { - return false, nil, errors.New("ssh: not enough answers from keyboard-interactive callback") + return authFailure, nil, errors.New("ssh: not enough answers from keyboard-interactive callback") } responseLength := 1 + 4 for _, a := range answers { @@ -446,7 +485,7 @@ func (cb KeyboardInteractiveChallenge) auth(session []byte, user string, c packe } if err := c.writePacket(serialized); err != nil { - return false, nil, err + return authFailure, nil, err } } } @@ -456,10 +495,10 @@ type retryableAuthMethod struct { maxTries int } -func (r *retryableAuthMethod) auth(session []byte, user string, c packetConn, rand io.Reader) (ok bool, methods []string, err error) { +func (r *retryableAuthMethod) auth(session []byte, user string, c packetConn, rand io.Reader) (ok authResult, methods []string, err error) { for i := 0; r.maxTries <= 0 || i < r.maxTries; i++ { ok, methods, err = r.authMethod.auth(session, user, c, rand) - if ok || err != nil { // either success or error terminate + if ok != authFailure || err != nil { // either success, partial success or error terminate return ok, methods, err } } |