diff options
Diffstat (limited to 'vendor/golang.org/x/crypto/ssh/server.go')
-rw-r--r-- | vendor/golang.org/x/crypto/ssh/server.go | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/vendor/golang.org/x/crypto/ssh/server.go b/vendor/golang.org/x/crypto/ssh/server.go index 77c84d165..8e95acc6a 100644 --- a/vendor/golang.org/x/crypto/ssh/server.go +++ b/vendor/golang.org/x/crypto/ssh/server.go @@ -45,6 +45,12 @@ type ServerConfig struct { // authenticating. NoClientAuth bool + // MaxAuthTries specifies the maximum number of authentication attempts + // permitted per connection. If set to a negative number, the number of + // attempts are unlimited. If set to zero, the number of attempts are limited + // to 6. + MaxAuthTries int + // PasswordCallback, if non-nil, is called when a user // attempts to authenticate using a password. PasswordCallback func(conn ConnMetadata, password []byte) (*Permissions, error) @@ -141,6 +147,10 @@ type ServerConn struct { // Request and NewChannel channels must be serviced, or the connection // will hang. func NewServerConn(c net.Conn, config *ServerConfig) (*ServerConn, <-chan NewChannel, <-chan *Request, error) { + if config.MaxAuthTries == 0 { + config.MaxAuthTries = 6 + } + fullConf := *config fullConf.SetDefaults() s := &connection{ @@ -267,8 +277,23 @@ func (s *connection) serverAuthenticate(config *ServerConfig) (*Permissions, err var cache pubKeyCache var perms *Permissions + authFailures := 0 + userAuthLoop: for { + if authFailures >= config.MaxAuthTries && config.MaxAuthTries > 0 { + discMsg := &disconnectMsg{ + Reason: 2, + Message: "too many authentication failures", + } + + if err := s.transport.writePacket(Marshal(discMsg)); err != nil { + return nil, err + } + + return nil, discMsg + } + var userAuthReq userAuthRequestMsg if packet, err := s.transport.readPacket(); err != nil { return nil, err @@ -289,6 +314,11 @@ userAuthLoop: if config.NoClientAuth { authErr = nil } + + // allow initial attempt of 'none' without penalty + if authFailures == 0 { + authFailures-- + } case "password": if config.PasswordCallback == nil { authErr = errors.New("ssh: password auth not configured") @@ -360,6 +390,7 @@ userAuthLoop: if isQuery { // The client can query if the given public key // would be okay. + if len(payload) > 0 { return nil, parseError(msgUserAuthRequest) } @@ -409,6 +440,8 @@ userAuthLoop: break userAuthLoop } + authFailures++ + var failureMsg userAuthFailureMsg if config.PasswordCallback != nil { failureMsg.Methods = append(failureMsg.Methods, "password") |