diff options
Diffstat (limited to 'vendor/golang.org/x/crypto/ssh')
| -rw-r--r-- | vendor/golang.org/x/crypto/ssh/channel.go | 28 | ||||
| -rw-r--r-- | vendor/golang.org/x/crypto/ssh/client.go | 2 | ||||
| -rw-r--r-- | vendor/golang.org/x/crypto/ssh/handshake.go | 56 | ||||
| -rw-r--r-- | vendor/golang.org/x/crypto/ssh/server.go | 2 | ||||
| -rw-r--r-- | vendor/golang.org/x/crypto/ssh/transport.go | 32 |
5 files changed, 102 insertions, 18 deletions
diff --git a/vendor/golang.org/x/crypto/ssh/channel.go b/vendor/golang.org/x/crypto/ssh/channel.go index c0834c00d..cc0bb7ab6 100644 --- a/vendor/golang.org/x/crypto/ssh/channel.go +++ b/vendor/golang.org/x/crypto/ssh/channel.go @@ -187,9 +187,11 @@ type channel struct { pending *buffer extPending *buffer - // windowMu protects myWindow, the flow-control window. - windowMu sync.Mutex - myWindow uint32 + // windowMu protects myWindow, the flow-control window, and myConsumed, + // the number of bytes consumed since we last increased myWindow + windowMu sync.Mutex + myWindow uint32 + myConsumed uint32 // writeMu serializes calls to mux.conn.writePacket() and // protects sentClose and packetPool. This mutex must be @@ -332,14 +334,24 @@ func (ch *channel) handleData(packet []byte) error { return nil } -func (c *channel) adjustWindow(n uint32) error { +func (c *channel) adjustWindow(adj uint32) error { c.windowMu.Lock() - // Since myWindow is managed on our side, and can never exceed - // the initial window setting, we don't worry about overflow. - c.myWindow += uint32(n) + // Since myConsumed and myWindow are managed on our side, and can never + // exceed the initial window setting, we don't worry about overflow. + c.myConsumed += adj + var sendAdj uint32 + if (channelWindowSize-c.myWindow > 3*c.maxIncomingPayload) || + (c.myWindow < channelWindowSize/2) { + sendAdj = c.myConsumed + c.myConsumed = 0 + c.myWindow += sendAdj + } c.windowMu.Unlock() + if sendAdj == 0 { + return nil + } return c.sendMessage(windowAdjustMsg{ - AdditionalBytes: uint32(n), + AdditionalBytes: sendAdj, }) } diff --git a/vendor/golang.org/x/crypto/ssh/client.go b/vendor/golang.org/x/crypto/ssh/client.go index bdc356cbd..fd8c49749 100644 --- a/vendor/golang.org/x/crypto/ssh/client.go +++ b/vendor/golang.org/x/crypto/ssh/client.go @@ -82,7 +82,7 @@ func NewClientConn(c net.Conn, addr string, config *ClientConfig) (Conn, <-chan if err := conn.clientHandshake(addr, &fullConf); err != nil { c.Close() - return nil, nil, nil, fmt.Errorf("ssh: handshake failed: %v", err) + return nil, nil, nil, fmt.Errorf("ssh: handshake failed: %w", err) } conn.mux = newMux(conn.transport) return conn, conn.mux.incomingChannels, conn.mux.incomingRequests, nil diff --git a/vendor/golang.org/x/crypto/ssh/handshake.go b/vendor/golang.org/x/crypto/ssh/handshake.go index 49bbba769..56cdc7c21 100644 --- a/vendor/golang.org/x/crypto/ssh/handshake.go +++ b/vendor/golang.org/x/crypto/ssh/handshake.go @@ -35,6 +35,16 @@ type keyingTransport interface { // direction will be effected if a msgNewKeys message is sent // or received. prepareKeyChange(*algorithms, *kexResult) error + + // setStrictMode sets the strict KEX mode, notably triggering + // sequence number resets on sending or receiving msgNewKeys. + // If the sequence number is already > 1 when setStrictMode + // is called, an error is returned. + setStrictMode() error + + // setInitialKEXDone indicates to the transport that the initial key exchange + // was completed + setInitialKEXDone() } // handshakeTransport implements rekeying on top of a keyingTransport @@ -100,6 +110,10 @@ type handshakeTransport struct { // The session ID or nil if first kex did not complete yet. sessionID []byte + + // strictMode indicates if the other side of the handshake indicated + // that we should be following the strict KEX protocol restrictions. + strictMode bool } type pendingKex struct { @@ -209,7 +223,10 @@ func (t *handshakeTransport) readLoop() { close(t.incoming) break } - if p[0] == msgIgnore || p[0] == msgDebug { + // If this is the first kex, and strict KEX mode is enabled, + // we don't ignore any messages, as they may be used to manipulate + // the packet sequence numbers. + if !(t.sessionID == nil && t.strictMode) && (p[0] == msgIgnore || p[0] == msgDebug) { continue } t.incoming <- p @@ -441,6 +458,11 @@ func (t *handshakeTransport) readOnePacket(first bool) ([]byte, error) { return successPacket, nil } +const ( + kexStrictClient = "kex-strict-c-v00@openssh.com" + kexStrictServer = "kex-strict-s-v00@openssh.com" +) + // sendKexInit sends a key change message. func (t *handshakeTransport) sendKexInit() error { t.mu.Lock() @@ -454,7 +476,6 @@ func (t *handshakeTransport) sendKexInit() error { } msg := &kexInitMsg{ - KexAlgos: t.config.KeyExchanges, CiphersClientServer: t.config.Ciphers, CiphersServerClient: t.config.Ciphers, MACsClientServer: t.config.MACs, @@ -464,6 +485,13 @@ func (t *handshakeTransport) sendKexInit() error { } io.ReadFull(rand.Reader, msg.Cookie[:]) + // We mutate the KexAlgos slice, in order to add the kex-strict extension algorithm, + // and possibly to add the ext-info extension algorithm. Since the slice may be the + // user owned KeyExchanges, we create our own slice in order to avoid using user + // owned memory by mistake. + msg.KexAlgos = make([]string, 0, len(t.config.KeyExchanges)+2) // room for kex-strict and ext-info + msg.KexAlgos = append(msg.KexAlgos, t.config.KeyExchanges...) + isServer := len(t.hostKeys) > 0 if isServer { for _, k := range t.hostKeys { @@ -488,17 +516,24 @@ func (t *handshakeTransport) sendKexInit() error { msg.ServerHostKeyAlgos = append(msg.ServerHostKeyAlgos, keyFormat) } } + + if t.sessionID == nil { + msg.KexAlgos = append(msg.KexAlgos, kexStrictServer) + } } else { msg.ServerHostKeyAlgos = t.hostKeyAlgorithms // As a client we opt in to receiving SSH_MSG_EXT_INFO so we know what // algorithms the server supports for public key authentication. See RFC // 8308, Section 2.1. + // + // We also send the strict KEX mode extension algorithm, in order to opt + // into the strict KEX mode. if firstKeyExchange := t.sessionID == nil; firstKeyExchange { - msg.KexAlgos = make([]string, 0, len(t.config.KeyExchanges)+1) - msg.KexAlgos = append(msg.KexAlgos, t.config.KeyExchanges...) msg.KexAlgos = append(msg.KexAlgos, "ext-info-c") + msg.KexAlgos = append(msg.KexAlgos, kexStrictClient) } + } packet := Marshal(msg) @@ -604,6 +639,13 @@ func (t *handshakeTransport) enterKeyExchange(otherInitPacket []byte) error { return err } + if t.sessionID == nil && ((isClient && contains(serverInit.KexAlgos, kexStrictServer)) || (!isClient && contains(clientInit.KexAlgos, kexStrictClient))) { + t.strictMode = true + if err := t.conn.setStrictMode(); err != nil { + return err + } + } + // We don't send FirstKexFollows, but we handle receiving it. // // RFC 4253 section 7 defines the kex and the agreement method for @@ -679,6 +721,12 @@ func (t *handshakeTransport) enterKeyExchange(otherInitPacket []byte) error { return unexpectedMessageError(msgNewKeys, packet[0]) } + if firstKeyExchange { + // Indicates to the transport that the first key exchange is completed + // after receiving SSH_MSG_NEWKEYS. + t.conn.setInitialKEXDone() + } + return nil } diff --git a/vendor/golang.org/x/crypto/ssh/server.go b/vendor/golang.org/x/crypto/ssh/server.go index 7f0c236a9..c2dfe3268 100644 --- a/vendor/golang.org/x/crypto/ssh/server.go +++ b/vendor/golang.org/x/crypto/ssh/server.go @@ -213,6 +213,7 @@ func NewServerConn(c net.Conn, config *ServerConfig) (*ServerConn, <-chan NewCha } else { for _, algo := range fullConf.PublicKeyAuthAlgorithms { if !contains(supportedPubKeyAuthAlgos, algo) { + c.Close() return nil, nil, nil, fmt.Errorf("ssh: unsupported public key authentication algorithm %s", algo) } } @@ -220,6 +221,7 @@ func NewServerConn(c net.Conn, config *ServerConfig) (*ServerConn, <-chan NewCha // Check if the config contains any unsupported key exchanges for _, kex := range fullConf.KeyExchanges { if _, ok := serverForbiddenKexAlgos[kex]; ok { + c.Close() return nil, nil, nil, fmt.Errorf("ssh: unsupported key exchange %s for server", kex) } } diff --git a/vendor/golang.org/x/crypto/ssh/transport.go b/vendor/golang.org/x/crypto/ssh/transport.go index da015801e..0424d2d37 100644 --- a/vendor/golang.org/x/crypto/ssh/transport.go +++ b/vendor/golang.org/x/crypto/ssh/transport.go @@ -49,6 +49,9 @@ type transport struct { rand io.Reader isClient bool io.Closer + + strictMode bool + initialKEXDone bool } // packetCipher represents a combination of SSH encryption/MAC @@ -74,6 +77,18 @@ type connectionState struct { pendingKeyChange chan packetCipher } +func (t *transport) setStrictMode() error { + if t.reader.seqNum != 1 { + return errors.New("ssh: sequence number != 1 when strict KEX mode requested") + } + t.strictMode = true + return nil +} + +func (t *transport) setInitialKEXDone() { + t.initialKEXDone = true +} + // prepareKeyChange sets up key material for a keychange. The key changes in // both directions are triggered by reading and writing a msgNewKey packet // respectively. @@ -112,11 +127,12 @@ func (t *transport) printPacket(p []byte, write bool) { // Read and decrypt next packet. func (t *transport) readPacket() (p []byte, err error) { for { - p, err = t.reader.readPacket(t.bufReader) + p, err = t.reader.readPacket(t.bufReader, t.strictMode) if err != nil { break } - if len(p) == 0 || (p[0] != msgIgnore && p[0] != msgDebug) { + // in strict mode we pass through DEBUG and IGNORE packets only during the initial KEX + if len(p) == 0 || (t.strictMode && !t.initialKEXDone) || (p[0] != msgIgnore && p[0] != msgDebug) { break } } @@ -127,7 +143,7 @@ func (t *transport) readPacket() (p []byte, err error) { return p, err } -func (s *connectionState) readPacket(r *bufio.Reader) ([]byte, error) { +func (s *connectionState) readPacket(r *bufio.Reader, strictMode bool) ([]byte, error) { packet, err := s.packetCipher.readCipherPacket(s.seqNum, r) s.seqNum++ if err == nil && len(packet) == 0 { @@ -140,6 +156,9 @@ func (s *connectionState) readPacket(r *bufio.Reader) ([]byte, error) { select { case cipher := <-s.pendingKeyChange: s.packetCipher = cipher + if strictMode { + s.seqNum = 0 + } default: return nil, errors.New("ssh: got bogus newkeys message") } @@ -170,10 +189,10 @@ func (t *transport) writePacket(packet []byte) error { if debugTransport { t.printPacket(packet, true) } - return t.writer.writePacket(t.bufWriter, t.rand, packet) + return t.writer.writePacket(t.bufWriter, t.rand, packet, t.strictMode) } -func (s *connectionState) writePacket(w *bufio.Writer, rand io.Reader, packet []byte) error { +func (s *connectionState) writePacket(w *bufio.Writer, rand io.Reader, packet []byte, strictMode bool) error { changeKeys := len(packet) > 0 && packet[0] == msgNewKeys err := s.packetCipher.writeCipherPacket(s.seqNum, w, rand, packet) @@ -188,6 +207,9 @@ func (s *connectionState) writePacket(w *bufio.Writer, rand io.Reader, packet [] select { case cipher := <-s.pendingKeyChange: s.packetCipher = cipher + if strictMode { + s.seqNum = 0 + } default: panic("ssh: no key material for msgNewKeys") } |