From c22fc41ddf6efc6741780d27c6e1627bd53212af Mon Sep 17 00:00:00 2001 From: Sebastiaan van Stijn Date: Tue, 19 Dec 2023 00:30:17 +0100 Subject: [PATCH] vendor: golang.org/x/crypto v0.17.0 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit update the package, which contains a fix in the ssh package. full diff: https://github.com/golang/crypto/compare/v0.16.0...v0.17.0 from the security mailing: > Hello gophers, > > Version v0.17.0 of golang.org/x/crypto fixes a protocol weakness in the > golang.org/x/crypto/ssh package that allowed a MITM attacker to compromise > the integrity of the secure channel before it was established, allowing > them to prevent transmission of a number of messages immediately after > the secure channel was established without either side being aware. > > The impact of this attack is relatively limited, as it does not compromise > confidentiality of the channel. Notably this attack would allow an attacker > to prevent the transmission of the SSH2_MSG_EXT_INFO message, disabling a > handful of newer security features. > > This protocol weakness was also fixed in OpenSSH 9.6. > > Thanks to Fabian Bäumer, Marcus Brinkmann, and Jörg Schwenk from Ruhr > University Bochum for reporting this issue. > > This is CVE-2023-48795 and Go issue https://go.dev/issue/64784. > > Cheers, > Roland on behalf of the Go team Signed-off-by: Sebastiaan van Stijn --- vendor.mod | 2 +- vendor.sum | 4 +- vendor/golang.org/x/crypto/ssh/channel.go | 28 ++++++++--- vendor/golang.org/x/crypto/ssh/client.go | 2 +- vendor/golang.org/x/crypto/ssh/handshake.go | 56 +++++++++++++++++++-- vendor/golang.org/x/crypto/ssh/server.go | 2 + vendor/golang.org/x/crypto/ssh/transport.go | 32 ++++++++++-- vendor/modules.txt | 2 +- 8 files changed, 106 insertions(+), 22 deletions(-) diff --git a/vendor.mod b/vendor.mod index 73ee317b8b..514347f696 100644 --- a/vendor.mod +++ b/vendor.mod @@ -202,7 +202,7 @@ require ( go.uber.org/atomic v1.9.0 // indirect go.uber.org/multierr v1.8.0 // indirect go.uber.org/zap v1.21.0 // indirect - golang.org/x/crypto v0.16.0 // indirect + golang.org/x/crypto v0.17.0 // indirect golang.org/x/oauth2 v0.10.0 // indirect golang.org/x/tools v0.10.0 // indirect google.golang.org/api v0.126.0 // indirect diff --git a/vendor.sum b/vendor.sum index 800388ed40..1537d35292 100644 --- a/vendor.sum +++ b/vendor.sum @@ -1394,8 +1394,8 @@ golang.org/x/crypto v0.0.0-20201124201722-c8d3bf9c5392/go.mod h1:jdWPYTVW3xRLrWP golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc= golang.org/x/crypto v0.0.0-20220314234659-1baeb1ce4c0b/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4= golang.org/x/crypto v0.0.0-20220411220226-7b82a4e95df4/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4= -golang.org/x/crypto v0.16.0 h1:mMMrFzRSCF0GvB7Ne27XVtVAaXLrPmgPC7/v0tkwHaY= -golang.org/x/crypto v0.16.0/go.mod h1:gCAAfMLgwOJRpTjQ2zCCt2OcSfYMTeZVSRtQlPC7Nq4= +golang.org/x/crypto v0.17.0 h1:r8bRNjWL3GshPW3gkd+RpvzWrZAwPS49OmTGZ/uhM4k= +golang.org/x/crypto v0.17.0/go.mod h1:gCAAfMLgwOJRpTjQ2zCCt2OcSfYMTeZVSRtQlPC7Nq4= golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA= golang.org/x/exp v0.0.0-20190125153040-c74c464bbbf2/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA= golang.org/x/exp v0.0.0-20190306152737-a1d7652674e8/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA= diff --git a/vendor/golang.org/x/crypto/ssh/channel.go b/vendor/golang.org/x/crypto/ssh/channel.go index c0834c00df..cc0bb7ab64 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 bdc356cbdf..fd8c49749e 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 49bbba7692..56cdc7c21c 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 7f0c236a9a..c2dfe3268c 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 da015801ea..0424d2d37c 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") } diff --git a/vendor/modules.txt b/vendor/modules.txt index 20b058dd44..daafd235ac 100644 --- a/vendor/modules.txt +++ b/vendor/modules.txt @@ -1217,7 +1217,7 @@ go.uber.org/zap/internal/bufferpool go.uber.org/zap/internal/color go.uber.org/zap/internal/exit go.uber.org/zap/zapcore -# golang.org/x/crypto v0.16.0 +# golang.org/x/crypto v0.17.0 ## explicit; go 1.18 golang.org/x/crypto/blowfish golang.org/x/crypto/chacha20