diff options
Diffstat (limited to 'vendor/golang.org/x/crypto/ssh/server.go')
| -rw-r--r-- | vendor/golang.org/x/crypto/ssh/server.go | 42 |
1 files changed, 36 insertions, 6 deletions
diff --git a/vendor/golang.org/x/crypto/ssh/server.go b/vendor/golang.org/x/crypto/ssh/server.go index 8a78b7c..d0f4825 100644 --- a/vendor/golang.org/x/crypto/ssh/server.go +++ b/vendor/golang.org/x/crypto/ssh/server.go @@ -95,6 +95,10 @@ type ServerConfig struct { // Note that RFC 4253 section 4.2 requires that this string start with // "SSH-2.0-". ServerVersion string + + // BannerCallback, if present, is called and the return string is sent to + // the client after key exchange completed but before authentication. + BannerCallback func(conn ConnMetadata) string } // AddHostKey adds a private key as a host key. If an existing host @@ -162,6 +166,9 @@ type ServerConn struct { // unsuccessful, it closes the connection and returns an error. The // Request and NewChannel channels must be serviced, or the connection // will hang. +// +// The returned error may be of type *ServerAuthError for +// authentication errors. func NewServerConn(c net.Conn, config *ServerConfig) (*ServerConn, <-chan NewChannel, <-chan *Request, error) { fullConf := *config fullConf.SetDefaults() @@ -252,7 +259,7 @@ func (s *connection) serverHandshake(config *ServerConfig) (*Permissions, error) func isAcceptableAlgo(algo string) bool { switch algo { case KeyAlgoRSA, KeyAlgoDSA, KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521, KeyAlgoED25519, - CertAlgoRSAv01, CertAlgoDSAv01, CertAlgoECDSA256v01, CertAlgoECDSA384v01, CertAlgoECDSA521v01: + CertAlgoRSAv01, CertAlgoDSAv01, CertAlgoECDSA256v01, CertAlgoECDSA384v01, CertAlgoECDSA521v01, CertAlgoED25519v01: return true } return false @@ -288,12 +295,13 @@ func checkSourceAddress(addr net.Addr, sourceAddrs string) error { return fmt.Errorf("ssh: remote address %v is not allowed because of source-address restriction", addr) } -// ServerAuthError implements the error interface. It appends any authentication -// errors that may occur, and is returned if all of the authentication methods -// provided by the user failed to authenticate. +// ServerAuthError represents server authentication errors and is +// sometimes returned by NewServerConn. It appends any authentication +// errors that may occur, and is returned if all of the authentication +// methods provided by the user failed to authenticate. type ServerAuthError struct { // Errors contains authentication errors returned by the authentication - // callback methods. + // callback methods. The first entry is typically ErrNoAuth. Errors []error } @@ -305,6 +313,13 @@ func (l ServerAuthError) Error() string { return "[" + strings.Join(errs, ", ") + "]" } +// ErrNoAuth is the error value returned if no +// authentication method has been passed yet. This happens as a normal +// part of the authentication loop, since the client first tries +// 'none' authentication to discover available methods. +// It is returned in ServerAuthError.Errors from NewServerConn. +var ErrNoAuth = errors.New("ssh: no auth passed yet") + func (s *connection) serverAuthenticate(config *ServerConfig) (*Permissions, error) { sessionID := s.transport.getSessionID() var cache pubKeyCache @@ -312,6 +327,7 @@ func (s *connection) serverAuthenticate(config *ServerConfig) (*Permissions, err authFailures := 0 var authErrs []error + var displayedBanner bool userAuthLoop: for { @@ -343,8 +359,22 @@ userAuthLoop: } s.user = userAuthReq.User + + if !displayedBanner && config.BannerCallback != nil { + displayedBanner = true + msg := config.BannerCallback(s) + if msg != "" { + bannerMsg := &userAuthBannerMsg{ + Message: msg, + } + if err := s.transport.writePacket(Marshal(bannerMsg)); err != nil { + return nil, err + } + } + } + perms = nil - authErr := errors.New("no auth passed yet") + authErr := ErrNoAuth switch userAuthReq.Method { case "none": |