vendor: update golang.org/x/crypto/ssh

Related to #4160

gogs.go

@@ -16,7 +16,7 @@ import (
 	"github.com/gogits/gogs/modules/setting"
 )
 
-const APP_VER = "0.10.3.0228"
+const APP_VER = "0.10.3.0301"
 
 func init() {
 	setting.AppVer = APP_VER

templates/.VERSION

@@ -1 +1 @@
-0.10.3.0228
+0.10.3.0301

vendor/golang.org/x/crypto/ssh/channel.go

@@ -461,8 +461,8 @@ func (m *mux) newChannel(chanType string, direction channelDirection, extraData
 		pending:          newBuffer(),
 		extPending:       newBuffer(),
 		direction:        direction,
-		incomingRequests: make(chan *Request, 16),
-		msg:              make(chan interface{}, 16),
+		incomingRequests: make(chan *Request, chanSize),
+		msg:              make(chan interface{}, chanSize),
 		chanType:         chanType,
 		extraData:        extraData,
 		mux:              m,

vendor/golang.org/x/crypto/ssh/cipher.go

@@ -135,6 +135,7 @@ const prefixLen = 5
 type streamPacketCipher struct {
 	mac    hash.Hash
 	cipher cipher.Stream
+	etm    bool
 
 	// The following members are to avoid per-packet allocations.
 	prefix      [prefixLen]byte
@@ -150,7 +151,14 @@ func (s *streamPacketCipher) readPacket(seqNum uint32, r io.Reader) ([]byte, err
 		return nil, err
 	}
 
-	s.cipher.XORKeyStream(s.prefix[:], s.prefix[:])
+	var encryptedPaddingLength [1]byte
+	if s.mac != nil && s.etm {
+		copy(encryptedPaddingLength[:], s.prefix[4:5])
+		s.cipher.XORKeyStream(s.prefix[4:5], s.prefix[4:5])
+	} else {
+		s.cipher.XORKeyStream(s.prefix[:], s.prefix[:])
+	}
+
 	length := binary.BigEndian.Uint32(s.prefix[0:4])
 	paddingLength := uint32(s.prefix[4])
 
@@ -159,7 +167,12 @@ func (s *streamPacketCipher) readPacket(seqNum uint32, r io.Reader) ([]byte, err
 		s.mac.Reset()
 		binary.BigEndian.PutUint32(s.seqNumBytes[:], seqNum)
 		s.mac.Write(s.seqNumBytes[:])
-		s.mac.Write(s.prefix[:])
+		if s.etm {
+			s.mac.Write(s.prefix[:4])
+			s.mac.Write(encryptedPaddingLength[:])
+		} else {
+			s.mac.Write(s.prefix[:])
+		}
 		macSize = uint32(s.mac.Size())
 	}
 
@@ -184,10 +197,17 @@ func (s *streamPacketCipher) readPacket(seqNum uint32, r io.Reader) ([]byte, err
 	}
 	mac := s.packetData[length-1:]
 	data := s.packetData[:length-1]
+
+	if s.mac != nil && s.etm {
+		s.mac.Write(data)
+	}
+
 	s.cipher.XORKeyStream(data, data)
 
 	if s.mac != nil {
-		s.mac.Write(data)
+		if !s.etm {
+			s.mac.Write(data)
+		}
 		s.macResult = s.mac.Sum(s.macResult[:0])
 		if subtle.ConstantTimeCompare(s.macResult, mac) != 1 {
 			return nil, errors.New("ssh: MAC failure")
@@ -203,7 +223,13 @@ func (s *streamPacketCipher) writePacket(seqNum uint32, w io.Writer, rand io.Rea
 		return errors.New("ssh: packet too large")
 	}
 
-	paddingLength := packetSizeMultiple - (prefixLen+len(packet))%packetSizeMultiple
+	aadlen := 0
+	if s.mac != nil && s.etm {
+		// packet length is not encrypted for EtM modes
+		aadlen = 4
+	}
+
+	paddingLength := packetSizeMultiple - (prefixLen+len(packet)-aadlen)%packetSizeMultiple
 	if paddingLength < 4 {
 		paddingLength += packetSizeMultiple
 	}
@@ -220,15 +246,37 @@ func (s *streamPacketCipher) writePacket(seqNum uint32, w io.Writer, rand io.Rea
 		s.mac.Reset()
 		binary.BigEndian.PutUint32(s.seqNumBytes[:], seqNum)
 		s.mac.Write(s.seqNumBytes[:])
+
+		if s.etm {
+			// For EtM algorithms, the packet length must stay unencrypted,
+			// but the following data (padding length) must be encrypted
+			s.cipher.XORKeyStream(s.prefix[4:5], s.prefix[4:5])
+		}
+
 		s.mac.Write(s.prefix[:])
-		s.mac.Write(packet)
-		s.mac.Write(padding)
+
+		if !s.etm {
+			// For non-EtM algorithms, the algorithm is applied on unencrypted data
+			s.mac.Write(packet)
+			s.mac.Write(padding)
+		}
+	}
+
+	if !(s.mac != nil && s.etm) {
+		// For EtM algorithms, the padding length has already been encrypted
+		// and the packet length must remain unencrypted
+		s.cipher.XORKeyStream(s.prefix[:], s.prefix[:])
 	}
 
-	s.cipher.XORKeyStream(s.prefix[:], s.prefix[:])
 	s.cipher.XORKeyStream(packet, packet)
 	s.cipher.XORKeyStream(padding, padding)
 
+	if s.mac != nil && s.etm {
+		// For EtM algorithms, packet and padding must be encrypted
+		s.mac.Write(packet)
+		s.mac.Write(padding)
+	}
+
 	if _, err := w.Write(s.prefix[:]); err != nil {
 		return err
 	}

vendor/golang.org/x/crypto/ssh/client.go

@@ -40,7 +40,7 @@ func (c *Client) HandleChannelOpen(channelType string) <-chan NewChannel {
 		return nil
 	}
 
-	ch = make(chan NewChannel, 16)
+	ch = make(chan NewChannel, chanSize)
 	c.channelHandlers[channelType] = ch
 	return ch
 }
@@ -97,13 +97,11 @@ func (c *connection) clientHandshake(dialAddress string, config *ClientConfig) e
 	c.transport = newClientTransport(
 		newTransport(c.sshConn.conn, config.Rand, true /* is client */),
 		c.clientVersion, c.serverVersion, config, dialAddress, c.sshConn.RemoteAddr())
-	if err := c.transport.requestInitialKeyChange(); err != nil {
+	if err := c.transport.waitSession(); err != nil {
 		return err
 	}
 
-	// We just did the key change, so the session ID is established.
 	c.sessionID = c.transport.getSessionID()
-
 	return c.clientAuthenticate(config)
 }
 

vendor/golang.org/x/crypto/ssh/client_auth.go

@@ -30,8 +30,10 @@ func (c *connection) clientAuthenticate(config *ClientConfig) error {
 	// then any untried methods suggested by the server.
 	tried := make(map[string]bool)
 	var lastMethods []string
+
+	sessionID := c.transport.getSessionID()
 	for auth := AuthMethod(new(noneAuth)); auth != nil; {
-		ok, methods, err := auth.auth(c.transport.getSessionID(), config.User, c.transport, config.Rand)
+		ok, methods, err := auth.auth(sessionID, config.User, c.transport, config.Rand)
 		if err != nil {
 			return err
 		}

vendor/golang.org/x/crypto/ssh/common.go

@@ -56,7 +56,7 @@ var supportedHostKeyAlgos = []string{
 // This is based on RFC 4253, section 6.4, but with hmac-md5 variants removed
 // because they have reached the end of their useful life.
 var supportedMACs = []string{
-	"hmac-sha2-256", "hmac-sha1", "hmac-sha1-96",
+	"hmac-sha2-256-etm@openssh.com", "hmac-sha2-256", "hmac-sha1", "hmac-sha1-96",
 }
 
 var supportedCompressions = []string{compressionNone}
@@ -104,6 +104,21 @@ type directionAlgorithms struct {
 	Compression string
 }
 
+// rekeyBytes returns a rekeying intervals in bytes.
+func (a *directionAlgorithms) rekeyBytes() int64 {
+	// According to RFC4344 block ciphers should rekey after
+	// 2^(BLOCKSIZE/4) blocks. For all AES flavors BLOCKSIZE is
+	// 128.
+	switch a.Cipher {
+	case "aes128-ctr", "aes192-ctr", "aes256-ctr", gcmCipherID, aes128cbcID:
+		return 16 * (1 << 32)
+
+	}
+
+	// For others, stick with RFC4253 recommendation to rekey after 1 Gb of data.
+	return 1 << 30
+}
+
 type algorithms struct {
 	kex     string
 	hostKey string

vendor/golang.org/x/crypto/ssh/handshake.go

@@ -19,6 +19,11 @@ import (
 // messages are wrong when using ECDH.
 const debugHandshake = false
 
+// chanSize sets the amount of buffering SSH connections. This is
+// primarily for testing: setting chanSize=0 uncovers deadlocks more
+// quickly.
+const chanSize = 16
+
 // keyingTransport is a packet based transport that supports key
 // changes. It need not be thread-safe. It should pass through
 // msgNewKeys in both directions.
@@ -53,34 +58,58 @@ type handshakeTransport struct {
 	incoming  chan []byte
 	readError error
 
+	mu             sync.Mutex
+	writeError     error
+	sentInitPacket []byte
+	sentInitMsg    *kexInitMsg
+	pendingPackets [][]byte // Used when a key exchange is in progress.
+
+	// If the read loop wants to schedule a kex, it pings this
+	// channel, and the write loop will send out a kex
+	// message.
+	requestKex chan struct{}
+
+	// If the other side requests or confirms a kex, its kexInit
+	// packet is sent here for the write loop to find it.
+	startKex chan *pendingKex
+
 	// data for host key checking
 	hostKeyCallback func(hostname string, remote net.Addr, key PublicKey) error
 	dialAddress     string
 	remoteAddr      net.Addr
 
-	readSinceKex uint64
+	// Algorithms agreed in the last key exchange.
+	algorithms *algorithms
+
+	readPacketsLeft uint32
+	readBytesLeft   int64
 
-	// Protects the writing side of the connection
-	mu              sync.Mutex
-	cond            *sync.Cond
-	sentInitPacket  []byte
-	sentInitMsg     *kexInitMsg
-	writtenSinceKex uint64
-	writeError      error
+	writePacketsLeft uint32
+	writeBytesLeft   int64
 
 	// The session ID or nil if first kex did not complete yet.
 	sessionID []byte
 }
 
+type pendingKex struct {
+	otherInit []byte
+	done      chan error
+}
+
 func newHandshakeTransport(conn keyingTransport, config *Config, clientVersion, serverVersion []byte) *handshakeTransport {
 	t := &handshakeTransport{
 		conn:          conn,
 		serverVersion: serverVersion,
 		clientVersion: clientVersion,
-		incoming:      make(chan []byte, 16),
-		config:        config,
+		incoming:      make(chan []byte, chanSize),
+		requestKex:    make(chan struct{}, 1),
+		startKex:      make(chan *pendingKex, 1),
+
+		config: config,
 	}
-	t.cond = sync.NewCond(&t.mu)
+
+	// We always start with a mandatory key exchange.
+	t.requestKex <- struct{}{}
 	return t
 }
 
@@ -95,6 +124,7 @@ func newClientTransport(conn keyingTransport, clientVersion, serverVersion []byt
 		t.hostKeyAlgorithms = supportedHostKeyAlgos
 	}
 	go t.readLoop()
+	go t.kexLoop()
 	return t
 }
 
@@ -102,6 +132,7 @@ func newServerTransport(conn keyingTransport, clientVersion, serverVersion []byt
 	t := newHandshakeTransport(conn, &config.Config, clientVersion, serverVersion)
 	t.hostKeys = config.hostKeys
 	go t.readLoop()
+	go t.kexLoop()
 	return t
 }
 
@@ -109,6 +140,20 @@ func (t *handshakeTransport) getSessionID() []byte {
 	return t.sessionID
 }
 
+// waitSession waits for the session to be established. This should be
+// the first thing to call after instantiating handshakeTransport.
+func (t *handshakeTransport) waitSession() error {
+	p, err := t.readPacket()
+	if err != nil {
+		return err
+	}
+	if p[0] != msgNewKeys {
+		return fmt.Errorf("ssh: first packet should be msgNewKeys")
+	}
+
+	return nil
+}
+
 func (t *handshakeTransport) id() string {
 	if len(t.hostKeys) > 0 {
 		return "server"
@@ -116,6 +161,20 @@ func (t *handshakeTransport) id() string {
 	return "client"
 }
 
+func (t *handshakeTransport) printPacket(p []byte, write bool) {
+	action := "got"
+	if write {
+		action = "sent"
+	}
+
+	if p[0] == msgChannelData || p[0] == msgChannelExtendedData {
+		log.Printf("%s %s data (packet %d bytes)", t.id(), action, len(p))
+	} else {
+		msg, err := decode(p)
+		log.Printf("%s %s %T %v (%v)", t.id(), action, msg, msg, err)
+	}
+}
+
 func (t *handshakeTransport) readPacket() ([]byte, error) {
 	p, ok := <-t.incoming
 	if !ok {
@@ -125,8 +184,10 @@ func (t *handshakeTransport) readPacket() ([]byte, error) {
 }
 
 func (t *handshakeTransport) readLoop() {
+	first := true
 	for {
-		p, err := t.readOnePacket()
+		p, err := t.readOnePacket(first)
+		first = false
 		if err != nil {
 			t.readError = err
 			close(t.incoming)
@@ -138,67 +199,204 @@ func (t *handshakeTransport) readLoop() {
 		t.incoming <- p
 	}
 
-	// If we can't read, declare the writing part dead too.
+	// Stop writers too.
+	t.recordWriteError(t.readError)
+
+	// Unblock the writer should it wait for this.
+	close(t.startKex)
+
+	// Don't close t.requestKex; it's also written to from writePacket.
+}
+
+func (t *handshakeTransport) pushPacket(p []byte) error {
+	if debugHandshake {
+		t.printPacket(p, true)
+	}
+	return t.conn.writePacket(p)
+}
+
+func (t *handshakeTransport) getWriteError() error {
 	t.mu.Lock()
 	defer t.mu.Unlock()
-	if t.writeError == nil {
-		t.writeError = t.readError
+	return t.writeError
+}
+
+func (t *handshakeTransport) recordWriteError(err error) {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	if t.writeError == nil && err != nil {
+		t.writeError = err
 	}
-	t.cond.Broadcast()
 }
 
-func (t *handshakeTransport) readOnePacket() ([]byte, error) {
-	if t.readSinceKex > t.config.RekeyThreshold {
-		if err := t.requestKeyChange(); err != nil {
-			return nil, err
+func (t *handshakeTransport) requestKeyExchange() {
+	select {
+	case t.requestKex <- struct{}{}:
+	default:
+		// something already requested a kex, so do nothing.
+	}
+}
+
+func (t *handshakeTransport) kexLoop() {
+
+write:
+	for t.getWriteError() == nil {
+		var request *pendingKex
+		var sent bool
+
+		for request == nil || !sent {
+			var ok bool
+			select {
+			case request, ok = <-t.startKex:
+				if !ok {
+					break write
+				}
+			case <-t.requestKex:
+				break
+			}
+
+			if !sent {
+				if err := t.sendKexInit(); err != nil {
+					t.recordWriteError(err)
+					break
+				}
+				sent = true
+			}
+		}
+
+		if err := t.getWriteError(); err != nil {
+			if request != nil {
+				request.done <- err
+			}
+			break
+		}
+
+		// We're not servicing t.requestKex, but that is OK:
+		// we never block on sending to t.requestKex.
+
+		// We're not servicing t.startKex, but the remote end
+		// has just sent us a kexInitMsg, so it can't send
+		// another key change request, until we close the done
+		// channel on the pendingKex request.
+
+		err := t.enterKeyExchange(request.otherInit)
+
+		t.mu.Lock()
+		t.writeError = err
+		t.sentInitPacket = nil
+		t.sentInitMsg = nil
+		t.writePacketsLeft = packetRekeyThreshold
+		if t.config.RekeyThreshold > 0 {
+			t.writeBytesLeft = int64(t.config.RekeyThreshold)
+		} else if t.algorithms != nil {
+			t.writeBytesLeft = t.algorithms.w.rekeyBytes()
+		}
+
+		// we have completed the key exchange. Since the
+		// reader is still blocked, it is safe to clear out
+		// the requestKex channel. This avoids the situation
+		// where: 1) we consumed our own request for the
+		// initial kex, and 2) the kex from the remote side
+		// caused another send on the requestKex channel,
+	clear:
+		for {
+			select {
+			case <-t.requestKex:
+				//
+			default:
+				break clear
+			}
+		}
+
+		request.done <- t.writeError
+
+		// kex finished. Push packets that we received while
+		// the kex was in progress. Don't look at t.startKex
+		// and don't increment writtenSinceKex: if we trigger
+		// another kex while we are still busy with the last
+		// one, things will become very confusing.
+		for _, p := range t.pendingPackets {
+			t.writeError = t.pushPacket(p)
+			if t.writeError != nil {
+				break
+			}
 		}
+		t.pendingPackets = t.pendingPackets[:0]
+		t.mu.Unlock()
 	}
 
+	// drain startKex channel. We don't service t.requestKex
+	// because nobody does blocking sends there.
+	go func() {
+		for init := range t.startKex {
+			init.done <- t.writeError
+		}
+	}()
+
+	// Unblock reader.
+	t.conn.Close()
+}
+
+// The protocol uses uint32 for packet counters, so we can't let them
+// reach 1<<32.  We will actually read and write more packets than
+// this, though: the other side may send more packets, and after we
+// hit this limit on writing we will send a few more packets for the
+// key exchange itself.
+const packetRekeyThreshold = (1 << 31)
+
+func (t *handshakeTransport) readOnePacket(first bool) ([]byte, error) {
 	p, err := t.conn.readPacket()
 	if err != nil {
 		return nil, err
 	}
 
-	t.readSinceKex += uint64(len(p))
+	if t.readPacketsLeft > 0 {
+		t.readPacketsLeft--
+	} else {
+		t.requestKeyExchange()
+	}
+
+	if t.readBytesLeft > 0 {
+		t.readBytesLeft -= int64(len(p))
+	} else {
+		t.requestKeyExchange()
+	}
+
 	if debugHandshake {
-		if p[0] == msgChannelData || p[0] == msgChannelExtendedData {
-			log.Printf("%s got data (packet %d bytes)", t.id(), len(p))
-		} else {
-			msg, err := decode(p)
-			log.Printf("%s got %T %v (%v)", t.id(), msg, msg, err)
-		}
+		t.printPacket(p, false)
+	}
+
+	if first && p[0] != msgKexInit {
+		return nil, fmt.Errorf("ssh: first packet should be msgKexInit")
 	}
+
 	if p[0] != msgKexInit {
 		return p, nil
 	}
 
-	t.mu.Lock()
-
 	firstKex := t.sessionID == nil
 
-	err = t.enterKeyExchangeLocked(p)
-	if err != nil {
-		// drop connection
-		t.conn.Close()
-		t.writeError = err
+	kex := pendingKex{
+		done:      make(chan error, 1),
+		otherInit: p,
 	}
+	t.startKex <- &kex
+	err = <-kex.done
 
 	if debugHandshake {
 		log.Printf("%s exited key exchange (first %v), err %v", t.id(), firstKex, err)
 	}
 
-	// Unblock writers.
-	t.sentInitMsg = nil
-	t.sentInitPacket = nil
-	t.cond.Broadcast()
-	t.writtenSinceKex = 0
-	t.mu.Unlock()
-
 	if err != nil {
 		return nil, err
 	}
 
-	t.readSinceKex = 0
+	t.readPacketsLeft = packetRekeyThreshold
+	if t.config.RekeyThreshold > 0 {
+		t.readBytesLeft = int64(t.config.RekeyThreshold)
+	} else {
+		t.readBytesLeft = t.algorithms.r.rekeyBytes()
+	}
 
 	// By default, a key exchange is hidden from higher layers by
 	// translating it into msgIgnore.
@@ -213,61 +411,16 @@ func (t *handshakeTransport) readOnePacket() ([]byte, error) {
 	return successPacket, nil
 }
 
-// keyChangeCategory describes whether a key exchange is the first on a
-// connection, or a subsequent one.
-type keyChangeCategory bool
-
-const (
-	firstKeyExchange      keyChangeCategory = true
-	subsequentKeyExchange keyChangeCategory = false
-)
-
-// sendKexInit sends a key change message, and returns the message
-// that was sent. After initiating the key change, all writes will be
-// blocked until the change is done, and a failed key change will
-// close the underlying transport. This function is safe for
-// concurrent use by multiple goroutines.
-func (t *handshakeTransport) sendKexInit(isFirst keyChangeCategory) error {
-	var err error
-
+// sendKexInit sends a key change message.
+func (t *handshakeTransport) sendKexInit() error {
 	t.mu.Lock()
-	// If this is the initial key change, but we already have a sessionID,
-	// then do nothing because the key exchange has already completed
-	// asynchronously.
-	if !isFirst || t.sessionID == nil {
-		_, _, err = t.sendKexInitLocked(isFirst)
-	}
-	t.mu.Unlock()
-	if err != nil {
-		return err
-	}
-	if isFirst {
-		if packet, err := t.readPacket(); err != nil {
-			return err
-		} else if packet[0] != msgNewKeys {
-			return unexpectedMessageError(msgNewKeys, packet[0])
-		}
-	}
-	return nil
-}
-
-func (t *handshakeTransport) requestInitialKeyChange() error {
-	return t.sendKexInit(firstKeyExchange)
-}
-
-func (t *handshakeTransport) requestKeyChange() error {
-	return t.sendKexInit(subsequentKeyExchange)
-}
-
-// sendKexInitLocked sends a key change message. t.mu must be locked
-// while this happens.
-func (t *handshakeTransport) sendKexInitLocked(isFirst keyChangeCategory) (*kexInitMsg, []byte, error) {
-	// kexInits may be sent either in response to the other side,
-	// or because our side wants to initiate a key change, so we
-	// may have already sent a kexInit. In that case, don't send a
-	// second kexInit.
+	defer t.mu.Unlock()
 	if t.sentInitMsg != nil {
-		return t.sentInitMsg, t.sentInitPacket, nil
+		// kexInits may be sent either in response to the other side,
+		// or because our side wants to initiate a key change, so we
+		// may have already sent a kexInit. In that case, don't send a
+		// second kexInit.
+		return nil
 	}
 
 	msg := &kexInitMsg{
@@ -295,53 +448,65 @@ func (t *handshakeTransport) sendKexInitLocked(isFirst keyChangeCategory) (*kexI
 	packetCopy := make([]byte, len(packet))
 	copy(packetCopy, packet)
 
-	if err := t.conn.writePacket(packetCopy); err != nil {
-		return nil, nil, err
+	if err := t.pushPacket(packetCopy); err != nil {
+		return err
 	}
 
 	t.sentInitMsg = msg
 	t.sentInitPacket = packet
-	return msg, packet, nil
+
+	return nil
 }
 
 func (t *handshakeTransport) writePacket(p []byte) error {
+	switch p[0] {
+	case msgKexInit:
+		return errors.New("ssh: only handshakeTransport can send kexInit")
+	case msgNewKeys:
+		return errors.New("ssh: only handshakeTransport can send newKeys")
+	}
+
 	t.mu.Lock()
 	defer t.mu.Unlock()
+	if t.writeError != nil {
+		return t.writeError
+	}
 
-	if t.writtenSinceKex > t.config.RekeyThreshold {
-		t.sendKexInitLocked(subsequentKeyExchange)
+	if t.sentInitMsg != nil {
+		// Copy the packet so the writer can reuse the buffer.
+		cp := make([]byte, len(p))
+		copy(cp, p)
+		t.pendingPackets = append(t.pendingPackets, cp)
+		return nil
 	}
-	for t.sentInitMsg != nil && t.writeError == nil {
-		t.cond.Wait()
+
+	if t.writeBytesLeft > 0 {
+		t.writeBytesLeft -= int64(len(p))
+	} else {
+		t.requestKeyExchange()
 	}
-	if t.writeError != nil {
-		return t.writeError
+
+	if t.writePacketsLeft > 0 {
+		t.writePacketsLeft--
+	} else {
+		t.requestKeyExchange()
 	}
-	t.writtenSinceKex += uint64(len(p))
 
-	switch p[0] {
-	case msgKexInit:
-		return errors.New("ssh: only handshakeTransport can send kexInit")
-	case msgNewKeys:
-		return errors.New("ssh: only handshakeTransport can send newKeys")
-	default:
-		return t.conn.writePacket(p)
+	if err := t.pushPacket(p); err != nil {
+		t.writeError = err
 	}
+
+	return nil
 }
 
 func (t *handshakeTransport) Close() error {
 	return t.conn.Close()
 }
 
-// enterKeyExchange runs the key exchange. t.mu must be held while running this.
-func (t *handshakeTransport) enterKeyExchangeLocked(otherInitPacket []byte) error {
+func (t *handshakeTransport) enterKeyExchange(otherInitPacket []byte) error {
 	if debugHandshake {
 		log.Printf("%s entered key exchange", t.id())
 	}
-	myInit, myInitPacket, err := t.sendKexInitLocked(subsequentKeyExchange)
-	if err != nil {
-		return err
-	}
 
 	otherInit := &kexInitMsg{}
 	if err := Unmarshal(otherInitPacket, otherInit); err != nil {
@@ -352,20 +517,20 @@ func (t *handshakeTransport) enterKeyExchangeLocked(otherInitPacket []byte) erro
 		clientVersion: t.clientVersion,
 		serverVersion: t.serverVersion,
 		clientKexInit: otherInitPacket,
-		serverKexInit: myInitPacket,
+		serverKexInit: t.sentInitPacket,
 	}
 
 	clientInit := otherInit
-	serverInit := myInit
+	serverInit := t.sentInitMsg
 	if len(t.hostKeys) == 0 {
-		clientInit = myInit
-		serverInit = otherInit
+		clientInit, serverInit = serverInit, clientInit
 
-		magics.clientKexInit = myInitPacket
+		magics.clientKexInit = t.sentInitPacket
 		magics.serverKexInit = otherInitPacket
 	}
 
-	algs, err := findAgreedAlgorithms(clientInit, serverInit)
+	var err error
+	t.algorithms, err = findAgreedAlgorithms(clientInit, serverInit)
 	if err != nil {
 		return err
 	}
@@ -388,16 +553,16 @@ func (t *handshakeTransport) enterKeyExchangeLocked(otherInitPacket []byte) erro
 		}
 	}
 
-	kex, ok := kexAlgoMap[algs.kex]
+	kex, ok := kexAlgoMap[t.algorithms.kex]
 	if !ok {
-		return fmt.Errorf("ssh: unexpected key exchange algorithm %v", algs.kex)
+		return fmt.Errorf("ssh: unexpected key exchange algorithm %v", t.algorithms.kex)
 	}
 
 	var result *kexResult
 	if len(t.hostKeys) > 0 {
-		result, err = t.server(kex, algs, &magics)
+		result, err = t.server(kex, t.algorithms, &magics)
 	} else {
-		result, err = t.client(kex, algs, &magics)
+		result, err = t.client(kex, t.algorithms, &magics)
 	}
 
 	if err != nil {
@@ -409,7 +574,7 @@ func (t *handshakeTransport) enterKeyExchangeLocked(otherInitPacket []byte) erro
 	}
 	result.SessionID = t.sessionID
 
-	t.conn.prepareKeyChange(algs, result)
+	t.conn.prepareKeyChange(t.algorithms, result)
 	if err = t.conn.writePacket([]byte{msgNewKeys}); err != nil {
 		return err
 	}

vendor/golang.org/x/crypto/ssh/keys.go

@@ -798,8 +798,8 @@ func ParseDSAPrivateKey(der []byte) (*dsa.PrivateKey, error) {
 		P       *big.Int
 		Q       *big.Int
 		G       *big.Int
-		Priv    *big.Int
 		Pub     *big.Int
+		Priv    *big.Int
 	}
 	rest, err := asn1.Unmarshal(der, &k)
 	if err != nil {
@@ -816,9 +816,9 @@ func ParseDSAPrivateKey(der []byte) (*dsa.PrivateKey, error) {
 				Q: k.Q,
 				G: k.G,
 			},
-			Y: k.Priv,
+			Y: k.Pub,
 		},
-		X: k.Pub,
+		X: k.Priv,
 	}, nil
 }
 

vendor/golang.org/x/crypto/ssh/mac.go

@@ -15,6 +15,7 @@ import (
 
 type macMode struct {
 	keySize int
+	etm     bool
 	new     func(key []byte) hash.Hash
 }
 
@@ -45,13 +46,16 @@ func (t truncatingMAC) Size() int {
 func (t truncatingMAC) BlockSize() int { return t.hmac.BlockSize() }
 
 var macModes = map[string]*macMode{
-	"hmac-sha2-256": {32, func(key []byte) hash.Hash {
+	"hmac-sha2-256-etm@openssh.com": {32, true, func(key []byte) hash.Hash {
 		return hmac.New(sha256.New, key)
 	}},
-	"hmac-sha1": {20, func(key []byte) hash.Hash {
+	"hmac-sha2-256": {32, false, func(key []byte) hash.Hash {
+		return hmac.New(sha256.New, key)
+	}},
+	"hmac-sha1": {20, false, func(key []byte) hash.Hash {
 		return hmac.New(sha1.New, key)
 	}},
-	"hmac-sha1-96": {20, func(key []byte) hash.Hash {
+	"hmac-sha1-96": {20, false, func(key []byte) hash.Hash {
 		return truncatingMAC{12, hmac.New(sha1.New, key)}
 	}},
 }

vendor/golang.org/x/crypto/ssh/mux.go

@@ -116,9 +116,9 @@ func (m *mux) Wait() error {
 func newMux(p packetConn) *mux {
 	m := &mux{
 		conn:             p,
-		incomingChannels: make(chan NewChannel, 16),
+		incomingChannels: make(chan NewChannel, chanSize),
 		globalResponses:  make(chan interface{}, 1),
-		incomingRequests: make(chan *Request, 16),
+		incomingRequests: make(chan *Request, chanSize),
 		errCond:          newCond(),
 	}
 	if debugMux {

vendor/golang.org/x/crypto/ssh/server.go

@@ -10,6 +10,7 @@ import (
 	"fmt"
 	"io"
 	"net"
+	"strings"
 )
 
 // The Permissions type holds fine-grained permissions that are
@@ -188,7 +189,7 @@ func (s *connection) serverHandshake(config *ServerConfig) (*Permissions, error)
 	tr := newTransport(s.sshConn.conn, config.Rand, false /* not client */)
 	s.transport = newServerTransport(tr, s.clientVersion, s.serverVersion, config)
 
-	if err := s.transport.requestInitialKeyChange(); err != nil {
+	if err := s.transport.waitSession(); err != nil {
 		return nil, err
 	}
 
@@ -231,7 +232,7 @@ func isAcceptableAlgo(algo string) bool {
 	return false
 }
 
-func checkSourceAddress(addr net.Addr, sourceAddr string) error {
+func checkSourceAddress(addr net.Addr, sourceAddrs string) error {
 	if addr == nil {
 		return errors.New("ssh: no address known for client, but source-address match required")
 	}
@@ -241,18 +242,20 @@ func checkSourceAddress(addr net.Addr, sourceAddr string) error {
 		return fmt.Errorf("ssh: remote address %v is not an TCP address when checking source-address match", addr)
 	}
 
-	if allowedIP := net.ParseIP(sourceAddr); allowedIP != nil {
-		if allowedIP.Equal(tcpAddr.IP) {
-			return nil
-		}
-	} else {
-		_, ipNet, err := net.ParseCIDR(sourceAddr)
-		if err != nil {
-			return fmt.Errorf("ssh: error parsing source-address restriction %q: %v", sourceAddr, err)
-		}
+	for _, sourceAddr := range strings.Split(sourceAddrs, ",") {
+		if allowedIP := net.ParseIP(sourceAddr); allowedIP != nil {
+			if allowedIP.Equal(tcpAddr.IP) {
+				return nil
+			}
+		} else {
+			_, ipNet, err := net.ParseCIDR(sourceAddr)
+			if err != nil {
+				return fmt.Errorf("ssh: error parsing source-address restriction %q: %v", sourceAddr, err)
+			}
 
-		if ipNet.Contains(tcpAddr.IP) {
-			return nil
+			if ipNet.Contains(tcpAddr.IP) {
+				return nil
+			}
 		}
 	}
 
@@ -260,7 +263,7 @@ func checkSourceAddress(addr net.Addr, sourceAddr string) error {
 }
 
 func (s *connection) serverAuthenticate(config *ServerConfig) (*Permissions, error) {
-	var err error
+	sessionID := s.transport.getSessionID()
 	var cache pubKeyCache
 	var perms *Permissions
 
@@ -385,7 +388,7 @@ userAuthLoop:
 				if !isAcceptableAlgo(sig.Format) {
 					break
 				}
-				signedData := buildDataSignedForAuth(s.transport.getSessionID(), userAuthReq, algoBytes, pubKeyData)
+				signedData := buildDataSignedForAuth(sessionID, userAuthReq, algoBytes, pubKeyData)
 
 				if err := pubKey.Verify(signedData, sig); err != nil {
 					return nil, err
@@ -421,12 +424,12 @@ userAuthLoop:
 			return nil, errors.New("ssh: no authentication methods configured but NoClientAuth is also false")
 		}
 
-		if err = s.transport.writePacket(Marshal(&failureMsg)); err != nil {
+		if err := s.transport.writePacket(Marshal(&failureMsg)); err != nil {
 			return nil, err
 		}
 	}
 
-	if err = s.transport.writePacket([]byte{msgUserAuthSuccess}); err != nil {
+	if err := s.transport.writePacket([]byte{msgUserAuthSuccess}); err != nil {
 		return nil, err
 	}
 	return perms, nil

vendor/golang.org/x/crypto/ssh/transport.go

@@ -8,8 +8,13 @@ import (
 	"bufio"
 	"errors"
 	"io"
+	"log"
 )
 
+// debugTransport if set, will print packet types as they go over the
+// wire. No message decoding is done, to minimize the impact on timing.
+const debugTransport = false
+
 const (
 	gcmCipherID    = "aes128-gcm@openssh.com"
 	aes128cbcID    = "aes128-cbc"
@@ -22,7 +27,9 @@ type packetConn interface {
 	// Encrypt and send a packet of data to the remote peer.
 	writePacket(packet []byte) error
 
-	// Read a packet from the connection
+	// Read a packet from the connection. The read is blocking,
+	// i.e. if error is nil, then the returned byte slice is
+	// always non-empty.
 	readPacket() ([]byte, error)
 
 	// Close closes the write-side of the connection.
@@ -38,7 +45,7 @@ type transport struct {
 	bufReader *bufio.Reader
 	bufWriter *bufio.Writer
 	rand      io.Reader
-
+	isClient  bool
 	io.Closer
 }
 
@@ -84,9 +91,38 @@ func (t *transport) prepareKeyChange(algs *algorithms, kexResult *kexResult) err
 	return nil
 }
 
+func (t *transport) printPacket(p []byte, write bool) {
+	if len(p) == 0 {
+		return
+	}
+	who := "server"
+	if t.isClient {
+		who = "client"
+	}
+	what := "read"
+	if write {
+		what = "write"
+	}
+
+	log.Println(what, who, p[0])
+}
+
 // Read and decrypt next packet.
-func (t *transport) readPacket() ([]byte, error) {
-	return t.reader.readPacket(t.bufReader)
+func (t *transport) readPacket() (p []byte, err error) {
+	for {
+		p, err = t.reader.readPacket(t.bufReader)
+		if err != nil {
+			break
+		}
+		if len(p) == 0 || (p[0] != msgIgnore && p[0] != msgDebug) {
+			break
+		}
+	}
+	if debugTransport {
+		t.printPacket(p, false)
+	}
+
+	return p, err
 }
 
 func (s *connectionState) readPacket(r *bufio.Reader) ([]byte, error) {
@@ -129,6 +165,9 @@ func (s *connectionState) readPacket(r *bufio.Reader) ([]byte, error) {
 }
 
 func (t *transport) writePacket(packet []byte) error {
+	if debugTransport {
+		t.printPacket(packet, true)
+	}
 	return t.writer.writePacket(t.bufWriter, t.rand, packet)
 }
 
@@ -169,6 +208,8 @@ func newTransport(rwc io.ReadWriteCloser, rand io.Reader, isClient bool) *transp
 		},
 		Closer: rwc,
 	}
+	t.isClient = isClient
+
 	if isClient {
 		t.reader.dir = serverKeys
 		t.writer.dir = clientKeys
@@ -226,6 +267,7 @@ func newPacketCipher(d direction, algs directionAlgorithms, kex *kexResult) (pac
 
 	c := &streamPacketCipher{
 		mac: macModes[algs.MAC].new(macKey),
+		etm: macModes[algs.MAC].etm,
 	}
 	c.macResult = make([]byte, c.mac.Size())
 

vendor/vendor.json

@@ -375,10 +375,10 @@
 			"revisionTime": "2016-12-13T22:25:08Z"
 		},
 		{
-			"checksumSHA1": "RnJfaFwKpC0h06J2MZ8UZX2eohc=",
+			"checksumSHA1": "fsrFs762jlaILyqqQImS1GfvIvw=",
 			"path": "golang.org/x/crypto/ssh",
-			"revision": "d8e61c69ab46ca38328da2f4995abaf93b252290",
-			"revisionTime": "2016-12-13T22:25:08Z"
+			"revision": "453249f01cfeb54c3d549ddb75ff152ca243f9d8",
+			"revisionTime": "2017-02-08T20:51:15Z"
 		},
 		{
 			"checksumSHA1": "9jjO5GjLa0XF/nfWihF02RoH4qc=",