diff --git a/vendor/github.com/gliderlabs/ssh/README.md b/vendor/github.com/gliderlabs/ssh/README.md
index 0522e03..0e976e3 100644
--- a/vendor/github.com/gliderlabs/ssh/README.md
+++ b/vendor/github.com/gliderlabs/ssh/README.md
@@ -14,7 +14,7 @@ package](https://godoc.org/golang.org/x/crypto/ssh) with a higher-level API for
 building SSH servers. The goal of the API was to make it as simple as using
 [net/http](https://golang.org/pkg/net/http/), so the API is very similar:
 
-```
+```go
  package main
 
  import (
diff --git a/vendor/github.com/gliderlabs/ssh/session.go b/vendor/github.com/gliderlabs/ssh/session.go
index 05a88a7..b16b432 100644
--- a/vendor/github.com/gliderlabs/ssh/session.go
+++ b/vendor/github.com/gliderlabs/ssh/session.go
@@ -71,8 +71,6 @@ type Session interface {
 	// If there are buffered signals when a channel is registered, they will be
 	// sent in order on the channel immediately after registering.
 	Signals(c chan<- Signal)
-
-	MaskedReqs() chan *gossh.Request
 }
 
 // maxSigBufSize is how many signals will be buffered
@@ -86,12 +84,11 @@ func sessionHandler(srv *Server, conn *gossh.ServerConn, newChan gossh.NewChanne
 		return
 	}
 	sess := &session{
-		Channel:    ch,
-		conn:       conn,
-		handler:    srv.Handler,
-		ptyCb:      srv.PtyCallback,
-		maskedReqs: make(chan *gossh.Request, 100),
-		ctx:        ctx,
+		Channel: ch,
+		conn:    conn,
+		handler: srv.Handler,
+		ptyCb:   srv.PtyCallback,
+		ctx:     ctx,
 	}
 	sess.handleRequests(reqs)
 }
@@ -99,19 +96,18 @@ func sessionHandler(srv *Server, conn *gossh.ServerConn, newChan gossh.NewChanne
 type session struct {
 	sync.Mutex
 	gossh.Channel
-	conn       *gossh.ServerConn
-	handler    Handler
-	handled    bool
-	exited     bool
-	pty        *Pty
-	winch      chan Window
-	env        []string
-	ptyCb      PtyCallback
-	cmd        []string
-	ctx        *sshContext
-	sigCh      chan<- Signal
-	sigBuf     []Signal
-	maskedReqs chan *gossh.Request
+	conn    *gossh.ServerConn
+	handler Handler
+	handled bool
+	exited  bool
+	pty     *Pty
+	winch   chan Window
+	env     []string
+	ptyCb   PtyCallback
+	cmd     []string
+	ctx     *sshContext
+	sigCh   chan<- Signal
+	sigBuf  []Signal
 }
 
 func (sess *session) Write(p []byte) (n int, err error) {
@@ -152,7 +148,6 @@ func (sess *session) Context() context.Context {
 func (sess *session) Exit(code int) error {
 	sess.Lock()
 	defer sess.Unlock()
-
 	if sess.exited {
 		return errors.New("Session.Exit called multiple times")
 	}
@@ -163,9 +158,6 @@ func (sess *session) Exit(code int) error {
 	if err != nil {
 		return err
 	}
-
-	close(sess.maskedReqs)
-
 	return sess.Close()
 }
 
@@ -209,10 +201,6 @@ func (sess *session) Signals(c chan<- Signal) {
 	}
 }
 
-func (sess *session) MaskedReqs() chan *gossh.Request {
-	return sess.maskedReqs
-}
-
 func (sess *session) handleRequests(reqs <-chan *gossh.Request) {
 	for req := range reqs {
 		switch req.Type {
@@ -295,7 +283,5 @@ func (sess *session) handleRequests(reqs <-chan *gossh.Request) {
 		default:
 			// TODO: debug log
 		}
-
-		sess.maskedReqs <- req
 	}
 }
diff --git a/vendor/github.com/gliderlabs/ssh/util.go b/vendor/github.com/gliderlabs/ssh/util.go
index 3e56b0a..c1fbc39 100644
--- a/vendor/github.com/gliderlabs/ssh/util.go
+++ b/vendor/github.com/gliderlabs/ssh/util.go
@@ -9,7 +9,7 @@ import (
 )
 
 func generateSigner() (ssh.Signer, error) {
-	key, err := rsa.GenerateKey(rand.Reader, 768)
+	key, err := rsa.GenerateKey(rand.Reader, 2048)
 	if err != nil {
 		return nil, err
 	}
diff --git a/vendor/golang.org/x/crypto/ssh/certs.go b/vendor/golang.org/x/crypto/ssh/certs.go
index b1f0220..5c9fadc 100644
--- a/vendor/golang.org/x/crypto/ssh/certs.go
+++ b/vendor/golang.org/x/crypto/ssh/certs.go
@@ -343,7 +343,7 @@ func (c *CertChecker) CheckCert(principal string, cert *Certificate) error {
 		return fmt.Errorf("ssh: certicate serial %d revoked", cert.Serial)
 	}
 
-	for opt, _ := range cert.CriticalOptions {
+	for opt := range cert.CriticalOptions {
 		// sourceAddressCriticalOption will be enforced by
 		// serverAuthenticate
 		if opt == sourceAddressCriticalOption {
diff --git a/vendor/golang.org/x/crypto/ssh/channel.go b/vendor/golang.org/x/crypto/ssh/channel.go
index 195530e..c0834c0 100644
--- a/vendor/golang.org/x/crypto/ssh/channel.go
+++ b/vendor/golang.org/x/crypto/ssh/channel.go
@@ -205,32 +205,32 @@ type channel struct {
 
 // writePacket sends a packet. If the packet is a channel close, it updates
 // sentClose. This method takes the lock c.writeMu.
-func (c *channel) writePacket(packet []byte) error {
-	c.writeMu.Lock()
-	if c.sentClose {
-		c.writeMu.Unlock()
+func (ch *channel) writePacket(packet []byte) error {
+	ch.writeMu.Lock()
+	if ch.sentClose {
+		ch.writeMu.Unlock()
 		return io.EOF
 	}
-	c.sentClose = (packet[0] == msgChannelClose)
-	err := c.mux.conn.writePacket(packet)
-	c.writeMu.Unlock()
+	ch.sentClose = (packet[0] == msgChannelClose)
+	err := ch.mux.conn.writePacket(packet)
+	ch.writeMu.Unlock()
 	return err
 }
 
-func (c *channel) sendMessage(msg interface{}) error {
+func (ch *channel) sendMessage(msg interface{}) error {
 	if debugMux {
-		log.Printf("send(%d): %#v", c.mux.chanList.offset, msg)
+		log.Printf("send(%d): %#v", ch.mux.chanList.offset, msg)
 	}
 
 	p := Marshal(msg)
-	binary.BigEndian.PutUint32(p[1:], c.remoteId)
-	return c.writePacket(p)
+	binary.BigEndian.PutUint32(p[1:], ch.remoteId)
+	return ch.writePacket(p)
 }
 
 // WriteExtended writes data to a specific extended stream. These streams are
 // used, for example, for stderr.
-func (c *channel) WriteExtended(data []byte, extendedCode uint32) (n int, err error) {
-	if c.sentEOF {
+func (ch *channel) WriteExtended(data []byte, extendedCode uint32) (n int, err error) {
+	if ch.sentEOF {
 		return 0, io.EOF
 	}
 	// 1 byte message type, 4 bytes remoteId, 4 bytes data length
@@ -241,16 +241,16 @@ func (c *channel) WriteExtended(data []byte, extendedCode uint32) (n int, err er
 		opCode = msgChannelExtendedData
 	}
 
-	c.writeMu.Lock()
-	packet := c.packetPool[extendedCode]
+	ch.writeMu.Lock()
+	packet := ch.packetPool[extendedCode]
 	// We don't remove the buffer from packetPool, so
 	// WriteExtended calls from different goroutines will be
 	// flagged as errors by the race detector.
-	c.writeMu.Unlock()
+	ch.writeMu.Unlock()
 
 	for len(data) > 0 {
-		space := min(c.maxRemotePayload, len(data))
-		if space, err = c.remoteWin.reserve(space); err != nil {
+		space := min(ch.maxRemotePayload, len(data))
+		if space, err = ch.remoteWin.reserve(space); err != nil {
 			return n, err
 		}
 		if want := headerLength + space; uint32(cap(packet)) < want {
@@ -262,13 +262,13 @@ func (c *channel) WriteExtended(data []byte, extendedCode uint32) (n int, err er
 		todo := data[:space]
 
 		packet[0] = opCode
-		binary.BigEndian.PutUint32(packet[1:], c.remoteId)
+		binary.BigEndian.PutUint32(packet[1:], ch.remoteId)
 		if extendedCode > 0 {
 			binary.BigEndian.PutUint32(packet[5:], uint32(extendedCode))
 		}
 		binary.BigEndian.PutUint32(packet[headerLength-4:], uint32(len(todo)))
 		copy(packet[headerLength:], todo)
-		if err = c.writePacket(packet); err != nil {
+		if err = ch.writePacket(packet); err != nil {
 			return n, err
 		}
 
@@ -276,14 +276,14 @@ func (c *channel) WriteExtended(data []byte, extendedCode uint32) (n int, err er
 		data = data[len(todo):]
 	}
 
-	c.writeMu.Lock()
-	c.packetPool[extendedCode] = packet
-	c.writeMu.Unlock()
+	ch.writeMu.Lock()
+	ch.packetPool[extendedCode] = packet
+	ch.writeMu.Unlock()
 
 	return n, err
 }
 
-func (c *channel) handleData(packet []byte) error {
+func (ch *channel) handleData(packet []byte) error {
 	headerLen := 9
 	isExtendedData := packet[0] == msgChannelExtendedData
 	if isExtendedData {
@@ -303,7 +303,7 @@ func (c *channel) handleData(packet []byte) error {
 	if length == 0 {
 		return nil
 	}
-	if length > c.maxIncomingPayload {
+	if length > ch.maxIncomingPayload {
 		// TODO(hanwen): should send Disconnect?
 		return errors.New("ssh: incoming packet exceeds maximum payload size")
 	}
@@ -313,21 +313,21 @@ func (c *channel) handleData(packet []byte) error {
 		return errors.New("ssh: wrong packet length")
 	}
 
-	c.windowMu.Lock()
-	if c.myWindow < length {
-		c.windowMu.Unlock()
+	ch.windowMu.Lock()
+	if ch.myWindow < length {
+		ch.windowMu.Unlock()
 		// TODO(hanwen): should send Disconnect with reason?
 		return errors.New("ssh: remote side wrote too much")
 	}
-	c.myWindow -= length
-	c.windowMu.Unlock()
+	ch.myWindow -= length
+	ch.windowMu.Unlock()
 
 	if extended == 1 {
-		c.extPending.write(data)
+		ch.extPending.write(data)
 	} else if extended > 0 {
 		// discard other extended data.
 	} else {
-		c.pending.write(data)
+		ch.pending.write(data)
 	}
 	return nil
 }
@@ -384,31 +384,31 @@ func (c *channel) close() {
 // responseMessageReceived is called when a success or failure message is
 // received on a channel to check that such a message is reasonable for the
 // given channel.
-func (c *channel) responseMessageReceived() error {
-	if c.direction == channelInbound {
+func (ch *channel) responseMessageReceived() error {
+	if ch.direction == channelInbound {
 		return errors.New("ssh: channel response message received on inbound channel")
 	}
-	if c.decided {
+	if ch.decided {
 		return errors.New("ssh: duplicate response received for channel")
 	}
-	c.decided = true
+	ch.decided = true
 	return nil
 }
 
-func (c *channel) handlePacket(packet []byte) error {
+func (ch *channel) handlePacket(packet []byte) error {
 	switch packet[0] {
 	case msgChannelData, msgChannelExtendedData:
-		return c.handleData(packet)
+		return ch.handleData(packet)
 	case msgChannelClose:
-		c.sendMessage(channelCloseMsg{PeersId: c.remoteId})
-		c.mux.chanList.remove(c.localId)
-		c.close()
+		ch.sendMessage(channelCloseMsg{PeersID: ch.remoteId})
+		ch.mux.chanList.remove(ch.localId)
+		ch.close()
 		return nil
 	case msgChannelEOF:
 		// RFC 4254 is mute on how EOF affects dataExt messages but
 		// it is logical to signal EOF at the same time.
-		c.extPending.eof()
-		c.pending.eof()
+		ch.extPending.eof()
+		ch.pending.eof()
 		return nil
 	}
 
@@ -419,24 +419,24 @@ func (c *channel) handlePacket(packet []byte) error {
 
 	switch msg := decoded.(type) {
 	case *channelOpenFailureMsg:
-		if err := c.responseMessageReceived(); err != nil {
+		if err := ch.responseMessageReceived(); err != nil {
 			return err
 		}
-		c.mux.chanList.remove(msg.PeersId)
-		c.msg <- msg
+		ch.mux.chanList.remove(msg.PeersID)
+		ch.msg <- msg
 	case *channelOpenConfirmMsg:
-		if err := c.responseMessageReceived(); err != nil {
+		if err := ch.responseMessageReceived(); err != nil {
 			return err
 		}
 		if msg.MaxPacketSize < minPacketLength || msg.MaxPacketSize > 1<<31 {
 			return fmt.Errorf("ssh: invalid MaxPacketSize %d from peer", msg.MaxPacketSize)
 		}
-		c.remoteId = msg.MyId
-		c.maxRemotePayload = msg.MaxPacketSize
-		c.remoteWin.add(msg.MyWindow)
-		c.msg <- msg
+		ch.remoteId = msg.MyID
+		ch.maxRemotePayload = msg.MaxPacketSize
+		ch.remoteWin.add(msg.MyWindow)
+		ch.msg <- msg
 	case *windowAdjustMsg:
-		if !c.remoteWin.add(msg.AdditionalBytes) {
+		if !ch.remoteWin.add(msg.AdditionalBytes) {
 			return fmt.Errorf("ssh: invalid window update for %d bytes", msg.AdditionalBytes)
 		}
 	case *channelRequestMsg:
@@ -444,12 +444,12 @@ func (c *channel) handlePacket(packet []byte) error {
 			Type:      msg.Request,
 			WantReply: msg.WantReply,
 			Payload:   msg.RequestSpecificData,
-			ch:        c,
+			ch:        ch,
 		}
 
-		c.incomingRequests <- &req
+		ch.incomingRequests <- &req
 	default:
-		c.msg <- msg
+		ch.msg <- msg
 	}
 	return nil
 }
@@ -488,23 +488,23 @@ func (e *extChannel) Read(data []byte) (n int, err error) {
 	return e.ch.ReadExtended(data, e.code)
 }
 
-func (c *channel) Accept() (Channel, <-chan *Request, error) {
-	if c.decided {
+func (ch *channel) Accept() (Channel, <-chan *Request, error) {
+	if ch.decided {
 		return nil, nil, errDecidedAlready
 	}
-	c.maxIncomingPayload = channelMaxPacket
+	ch.maxIncomingPayload = channelMaxPacket
 	confirm := channelOpenConfirmMsg{
-		PeersId:       c.remoteId,
-		MyId:          c.localId,
-		MyWindow:      c.myWindow,
-		MaxPacketSize: c.maxIncomingPayload,
+		PeersID:       ch.remoteId,
+		MyID:          ch.localId,
+		MyWindow:      ch.myWindow,
+		MaxPacketSize: ch.maxIncomingPayload,
 	}
-	c.decided = true
-	if err := c.sendMessage(confirm); err != nil {
+	ch.decided = true
+	if err := ch.sendMessage(confirm); err != nil {
 		return nil, nil, err
 	}
 
-	return c, c.incomingRequests, nil
+	return ch, ch.incomingRequests, nil
 }
 
 func (ch *channel) Reject(reason RejectionReason, message string) error {
@@ -512,7 +512,7 @@ func (ch *channel) Reject(reason RejectionReason, message string) error {
 		return errDecidedAlready
 	}
 	reject := channelOpenFailureMsg{
-		PeersId:  ch.remoteId,
+		PeersID:  ch.remoteId,
 		Reason:   reason,
 		Message:  message,
 		Language: "en",
@@ -541,7 +541,7 @@ func (ch *channel) CloseWrite() error {
 	}
 	ch.sentEOF = true
 	return ch.sendMessage(channelEOFMsg{
-		PeersId: ch.remoteId})
+		PeersID: ch.remoteId})
 }
 
 func (ch *channel) Close() error {
@@ -550,7 +550,7 @@ func (ch *channel) Close() error {
 	}
 
 	return ch.sendMessage(channelCloseMsg{
-		PeersId: ch.remoteId})
+		PeersID: ch.remoteId})
 }
 
 // Extended returns an io.ReadWriter that sends and receives data on the given,
@@ -577,7 +577,7 @@ func (ch *channel) SendRequest(name string, wantReply bool, payload []byte) (boo
 	}
 
 	msg := channelRequestMsg{
-		PeersId:             ch.remoteId,
+		PeersID:             ch.remoteId,
 		Request:             name,
 		WantReply:           wantReply,
 		RequestSpecificData: payload,
@@ -614,11 +614,11 @@ func (ch *channel) ackRequest(ok bool) error {
 	var msg interface{}
 	if !ok {
 		msg = channelRequestFailureMsg{
-			PeersId: ch.remoteId,
+			PeersID: ch.remoteId,
 		}
 	} else {
 		msg = channelRequestSuccessMsg{
-			PeersId: ch.remoteId,
+			PeersID: ch.remoteId,
 		}
 	}
 	return ch.sendMessage(msg)
diff --git a/vendor/golang.org/x/crypto/ssh/cipher.go b/vendor/golang.org/x/crypto/ssh/cipher.go
index 22bb30c..e67c5e0 100644
--- a/vendor/golang.org/x/crypto/ssh/cipher.go
+++ b/vendor/golang.org/x/crypto/ssh/cipher.go
@@ -304,7 +304,7 @@ type gcmCipher struct {
 	buf    []byte
 }
 
-func newGCMCipher(iv, key, macKey []byte) (packetCipher, error) {
+func newGCMCipher(iv, key []byte) (packetCipher, error) {
 	c, err := aes.NewCipher(key)
 	if err != nil {
 		return nil, err
@@ -372,7 +372,7 @@ func (c *gcmCipher) readPacket(seqNum uint32, r io.Reader) ([]byte, error) {
 	}
 	length := binary.BigEndian.Uint32(c.prefix[:])
 	if length > maxPacket {
-		return nil, errors.New("ssh: max packet length exceeded.")
+		return nil, errors.New("ssh: max packet length exceeded")
 	}
 
 	if cap(c.buf) < int(length+gcmTagSize) {
@@ -548,11 +548,11 @@ func (c *cbcCipher) readPacketLeaky(seqNum uint32, r io.Reader) ([]byte, error)
 		c.packetData = c.packetData[:entirePacketSize]
 	}
 
-	if n, err := io.ReadFull(r, c.packetData[firstBlockLength:]); err != nil {
+	n, err := io.ReadFull(r, c.packetData[firstBlockLength:])
+	if err != nil {
 		return nil, err
-	} else {
-		c.oracleCamouflage -= uint32(n)
 	}
+	c.oracleCamouflage -= uint32(n)
 
 	remainingCrypted := c.packetData[firstBlockLength:macStart]
 	c.decrypter.CryptBlocks(remainingCrypted, remainingCrypted)
diff --git a/vendor/golang.org/x/crypto/ssh/client.go b/vendor/golang.org/x/crypto/ssh/client.go
index a7e3263..6fd1994 100644
--- a/vendor/golang.org/x/crypto/ssh/client.go
+++ b/vendor/golang.org/x/crypto/ssh/client.go
@@ -9,6 +9,7 @@ import (
 	"errors"
 	"fmt"
 	"net"
+	"os"
 	"sync"
 	"time"
 )
@@ -187,6 +188,10 @@ func Dial(network, addr string, config *ClientConfig) (*Client, error) {
 // net.Conn underlying the the SSH connection.
 type HostKeyCallback func(hostname string, remote net.Addr, key PublicKey) error
 
+// BannerCallback is the function type used for treat the banner sent by
+// the server. A BannerCallback receives the message sent by the remote server.
+type BannerCallback func(message string) error
+
 // A ClientConfig structure is used to configure a Client. It must not be
 // modified after having been passed to an SSH function.
 type ClientConfig struct {
@@ -209,6 +214,12 @@ type ClientConfig struct {
 	// FixedHostKey can be used for simplistic host key checks.
 	HostKeyCallback HostKeyCallback
 
+	// BannerCallback is called during the SSH dance to display a custom
+	// server's message. The client configuration can supply this callback to
+	// handle it as wished. The function BannerDisplayStderr can be used for
+	// simplistic display on Stderr.
+	BannerCallback BannerCallback
+
 	// ClientVersion contains the version identification string that will
 	// be used for the connection. If empty, a reasonable default is used.
 	ClientVersion string
@@ -255,3 +266,13 @@ func FixedHostKey(key PublicKey) HostKeyCallback {
 	hk := &fixedHostKey{key}
 	return hk.check
 }
+
+// BannerDisplayStderr returns a function that can be used for
+// ClientConfig.BannerCallback to display banners on os.Stderr.
+func BannerDisplayStderr() BannerCallback {
+	return func(banner string) error {
+		_, err := os.Stderr.WriteString(banner)
+
+		return err
+	}
+}
diff --git a/vendor/golang.org/x/crypto/ssh/client_auth.go b/vendor/golang.org/x/crypto/ssh/client_auth.go
index 3acd8d4..a1252cb 100644
--- a/vendor/golang.org/x/crypto/ssh/client_auth.go
+++ b/vendor/golang.org/x/crypto/ssh/client_auth.go
@@ -283,7 +283,9 @@ func confirmKeyAck(key PublicKey, c packetConn) (bool, error) {
 		}
 		switch packet[0] {
 		case msgUserAuthBanner:
-			// TODO(gpaul): add callback to present the banner to the user
+			if err := handleBannerResponse(c, packet); err != nil {
+				return false, err
+			}
 		case msgUserAuthPubKeyOk:
 			var msg userAuthPubKeyOkMsg
 			if err := Unmarshal(packet, &msg); err != nil {
@@ -325,7 +327,9 @@ func handleAuthResponse(c packetConn) (bool, []string, error) {
 
 		switch packet[0] {
 		case msgUserAuthBanner:
-			// TODO: add callback to present the banner to the user
+			if err := handleBannerResponse(c, packet); err != nil {
+				return false, nil, err
+			}
 		case msgUserAuthFailure:
 			var msg userAuthFailureMsg
 			if err := Unmarshal(packet, &msg); err != nil {
@@ -340,6 +344,24 @@ func handleAuthResponse(c packetConn) (bool, []string, error) {
 	}
 }
 
+func handleBannerResponse(c packetConn, packet []byte) error {
+	var msg userAuthBannerMsg
+	if err := Unmarshal(packet, &msg); err != nil {
+		return err
+	}
+
+	transport, ok := c.(*handshakeTransport)
+	if !ok {
+		return nil
+	}
+
+	if transport.bannerCallback != nil {
+		return transport.bannerCallback(msg.Message)
+	}
+
+	return nil
+}
+
 // KeyboardInteractiveChallenge should print questions, optionally
 // disabling echoing (e.g. for passwords), and return all the answers.
 // Challenge may be called multiple times in a single session. After
@@ -385,7 +407,9 @@ func (cb KeyboardInteractiveChallenge) auth(session []byte, user string, c packe
 		// like handleAuthResponse, but with less options.
 		switch packet[0] {
 		case msgUserAuthBanner:
-			// TODO: Print banners during userauth.
+			if err := handleBannerResponse(c, packet); err != nil {
+				return false, nil, err
+			}
 			continue
 		case msgUserAuthInfoRequest:
 			// OK
diff --git a/vendor/golang.org/x/crypto/ssh/common.go b/vendor/golang.org/x/crypto/ssh/common.go
index dc39e4d..135b4ed 100644
--- a/vendor/golang.org/x/crypto/ssh/common.go
+++ b/vendor/golang.org/x/crypto/ssh/common.go
@@ -242,7 +242,7 @@ func (c *Config) SetDefaults() {
 
 // buildDataSignedForAuth returns the data that is signed in order to prove
 // possession of a private key. See RFC 4252, section 7.
-func buildDataSignedForAuth(sessionId []byte, req userAuthRequestMsg, algo, pubKey []byte) []byte {
+func buildDataSignedForAuth(sessionID []byte, req userAuthRequestMsg, algo, pubKey []byte) []byte {
 	data := struct {
 		Session []byte
 		Type    byte
@@ -253,7 +253,7 @@ func buildDataSignedForAuth(sessionId []byte, req userAuthRequestMsg, algo, pubK
 		Algo    []byte
 		PubKey  []byte
 	}{
-		sessionId,
+		sessionID,
 		msgUserAuthRequest,
 		req.User,
 		req.Service,
diff --git a/vendor/golang.org/x/crypto/ssh/handshake.go b/vendor/golang.org/x/crypto/ssh/handshake.go
index 932ce83..4f7912e 100644
--- a/vendor/golang.org/x/crypto/ssh/handshake.go
+++ b/vendor/golang.org/x/crypto/ssh/handshake.go
@@ -78,6 +78,11 @@ type handshakeTransport struct {
 	dialAddress     string
 	remoteAddr      net.Addr
 
+	// bannerCallback is non-empty if we are the client and it has been set in
+	// ClientConfig. In that case it is called during the user authentication
+	// dance to handle a custom server's message.
+	bannerCallback BannerCallback
+
 	// Algorithms agreed in the last key exchange.
 	algorithms *algorithms
 
@@ -120,6 +125,7 @@ func newClientTransport(conn keyingTransport, clientVersion, serverVersion []byt
 	t.dialAddress = dialAddr
 	t.remoteAddr = addr
 	t.hostKeyCallback = config.HostKeyCallback
+	t.bannerCallback = config.BannerCallback
 	if config.HostKeyAlgorithms != nil {
 		t.hostKeyAlgorithms = config.HostKeyAlgorithms
 	} else {
diff --git a/vendor/golang.org/x/crypto/ssh/kex.go b/vendor/golang.org/x/crypto/ssh/kex.go
index f91c277..f34bcc0 100644
--- a/vendor/golang.org/x/crypto/ssh/kex.go
+++ b/vendor/golang.org/x/crypto/ssh/kex.go
@@ -119,7 +119,7 @@ func (group *dhGroup) Client(c packetConn, randSource io.Reader, magics *handsha
 		return nil, err
 	}
 
-	kInt, err := group.diffieHellman(kexDHReply.Y, x)
+	ki, err := group.diffieHellman(kexDHReply.Y, x)
 	if err != nil {
 		return nil, err
 	}
@@ -129,8 +129,8 @@ func (group *dhGroup) Client(c packetConn, randSource io.Reader, magics *handsha
 	writeString(h, kexDHReply.HostKey)
 	writeInt(h, X)
 	writeInt(h, kexDHReply.Y)
-	K := make([]byte, intLength(kInt))
-	marshalInt(K, kInt)
+	K := make([]byte, intLength(ki))
+	marshalInt(K, ki)
 	h.Write(K)
 
 	return &kexResult{
@@ -164,7 +164,7 @@ func (group *dhGroup) Server(c packetConn, randSource io.Reader, magics *handsha
 	}
 
 	Y := new(big.Int).Exp(group.g, y, group.p)
-	kInt, err := group.diffieHellman(kexDHInit.X, y)
+	ki, err := group.diffieHellman(kexDHInit.X, y)
 	if err != nil {
 		return nil, err
 	}
@@ -177,8 +177,8 @@ func (group *dhGroup) Server(c packetConn, randSource io.Reader, magics *handsha
 	writeInt(h, kexDHInit.X)
 	writeInt(h, Y)
 
-	K := make([]byte, intLength(kInt))
-	marshalInt(K, kInt)
+	K := make([]byte, intLength(ki))
+	marshalInt(K, ki)
 	h.Write(K)
 
 	H := h.Sum(nil)
@@ -462,9 +462,9 @@ func (kex *curve25519sha256) Client(c packetConn, rand io.Reader, magics *handsh
 	writeString(h, kp.pub[:])
 	writeString(h, reply.EphemeralPubKey)
 
-	kInt := new(big.Int).SetBytes(secret[:])
-	K := make([]byte, intLength(kInt))
-	marshalInt(K, kInt)
+	ki := new(big.Int).SetBytes(secret[:])
+	K := make([]byte, intLength(ki))
+	marshalInt(K, ki)
 	h.Write(K)
 
 	return &kexResult{
@@ -510,9 +510,9 @@ func (kex *curve25519sha256) Server(c packetConn, rand io.Reader, magics *handsh
 	writeString(h, kexInit.ClientPubKey)
 	writeString(h, kp.pub[:])
 
-	kInt := new(big.Int).SetBytes(secret[:])
-	K := make([]byte, intLength(kInt))
-	marshalInt(K, kInt)
+	ki := new(big.Int).SetBytes(secret[:])
+	K := make([]byte, intLength(ki))
+	marshalInt(K, ki)
 	h.Write(K)
 
 	H := h.Sum(nil)
diff --git a/vendor/golang.org/x/crypto/ssh/keys.go b/vendor/golang.org/x/crypto/ssh/keys.go
index b682c17..dadf41a 100644
--- a/vendor/golang.org/x/crypto/ssh/keys.go
+++ b/vendor/golang.org/x/crypto/ssh/keys.go
@@ -363,7 +363,7 @@ func (r *rsaPublicKey) CryptoPublicKey() crypto.PublicKey {
 
 type dsaPublicKey dsa.PublicKey
 
-func (r *dsaPublicKey) Type() string {
+func (k *dsaPublicKey) Type() string {
 	return "ssh-dss"
 }
 
@@ -481,12 +481,12 @@ func (k *dsaPrivateKey) Sign(rand io.Reader, data []byte) (*Signature, error) {
 
 type ecdsaPublicKey ecdsa.PublicKey
 
-func (key *ecdsaPublicKey) Type() string {
-	return "ecdsa-sha2-" + key.nistID()
+func (k *ecdsaPublicKey) Type() string {
+	return "ecdsa-sha2-" + k.nistID()
 }
 
-func (key *ecdsaPublicKey) nistID() string {
-	switch key.Params().BitSize {
+func (k *ecdsaPublicKey) nistID() string {
+	switch k.Params().BitSize {
 	case 256:
 		return "nistp256"
 	case 384:
@@ -499,7 +499,7 @@ func (key *ecdsaPublicKey) nistID() string {
 
 type ed25519PublicKey ed25519.PublicKey
 
-func (key ed25519PublicKey) Type() string {
+func (k ed25519PublicKey) Type() string {
 	return KeyAlgoED25519
 }
 
@@ -518,23 +518,23 @@ func parseED25519(in []byte) (out PublicKey, rest []byte, err error) {
 	return (ed25519PublicKey)(key), w.Rest, nil
 }
 
-func (key ed25519PublicKey) Marshal() []byte {
+func (k ed25519PublicKey) Marshal() []byte {
 	w := struct {
 		Name     string
 		KeyBytes []byte
 	}{
 		KeyAlgoED25519,
-		[]byte(key),
+		[]byte(k),
 	}
 	return Marshal(&w)
 }
 
-func (key ed25519PublicKey) Verify(b []byte, sig *Signature) error {
-	if sig.Format != key.Type() {
-		return fmt.Errorf("ssh: signature type %s for key type %s", sig.Format, key.Type())
+func (k ed25519PublicKey) Verify(b []byte, sig *Signature) error {
+	if sig.Format != k.Type() {
+		return fmt.Errorf("ssh: signature type %s for key type %s", sig.Format, k.Type())
 	}
 
-	edKey := (ed25519.PublicKey)(key)
+	edKey := (ed25519.PublicKey)(k)
 	if ok := ed25519.Verify(edKey, b, sig.Blob); !ok {
 		return errors.New("ssh: signature did not verify")
 	}
@@ -595,9 +595,9 @@ func parseECDSA(in []byte) (out PublicKey, rest []byte, err error) {
 	return (*ecdsaPublicKey)(key), w.Rest, nil
 }
 
-func (key *ecdsaPublicKey) Marshal() []byte {
+func (k *ecdsaPublicKey) Marshal() []byte {
 	// See RFC 5656, section 3.1.
-	keyBytes := elliptic.Marshal(key.Curve, key.X, key.Y)
+	keyBytes := elliptic.Marshal(k.Curve, k.X, k.Y)
 	// ECDSA publickey struct layout should match the struct used by
 	// parseECDSACert in the x/crypto/ssh/agent package.
 	w := struct {
@@ -605,20 +605,20 @@ func (key *ecdsaPublicKey) Marshal() []byte {
 		ID   string
 		Key  []byte
 	}{
-		key.Type(),
-		key.nistID(),
+		k.Type(),
+		k.nistID(),
 		keyBytes,
 	}
 
 	return Marshal(&w)
 }
 
-func (key *ecdsaPublicKey) Verify(data []byte, sig *Signature) error {
-	if sig.Format != key.Type() {
-		return fmt.Errorf("ssh: signature type %s for key type %s", sig.Format, key.Type())
+func (k *ecdsaPublicKey) Verify(data []byte, sig *Signature) error {
+	if sig.Format != k.Type() {
+		return fmt.Errorf("ssh: signature type %s for key type %s", sig.Format, k.Type())
 	}
 
-	h := ecHash(key.Curve).New()
+	h := ecHash(k.Curve).New()
 	h.Write(data)
 	digest := h.Sum(nil)
 
@@ -635,7 +635,7 @@ func (key *ecdsaPublicKey) Verify(data []byte, sig *Signature) error {
 		return err
 	}
 
-	if ecdsa.Verify((*ecdsa.PublicKey)(key), digest, ecSig.R, ecSig.S) {
+	if ecdsa.Verify((*ecdsa.PublicKey)(k), digest, ecSig.R, ecSig.S) {
 		return nil
 	}
 	return errors.New("ssh: signature did not verify")
@@ -758,7 +758,7 @@ func NewPublicKey(key interface{}) (PublicKey, error) {
 		return (*rsaPublicKey)(key), nil
 	case *ecdsa.PublicKey:
 		if !supportedEllipticCurve(key.Curve) {
-			return nil, errors.New("ssh: only P-256, P-384 and P-521 EC keys are supported.")
+			return nil, errors.New("ssh: only P-256, P-384 and P-521 EC keys are supported")
 		}
 		return (*ecdsaPublicKey)(key), nil
 	case *dsa.PublicKey:
diff --git a/vendor/golang.org/x/crypto/ssh/messages.go b/vendor/golang.org/x/crypto/ssh/messages.go
index e6ecd3a..08d2811 100644
--- a/vendor/golang.org/x/crypto/ssh/messages.go
+++ b/vendor/golang.org/x/crypto/ssh/messages.go
@@ -23,10 +23,6 @@ const (
 	msgUnimplemented = 3
 	msgDebug         = 4
 	msgNewKeys       = 21
-
-	// Standard authentication messages
-	msgUserAuthSuccess = 52
-	msgUserAuthBanner  = 53
 )
 
 // SSH messages:
@@ -137,6 +133,18 @@ type userAuthFailureMsg struct {
 	PartialSuccess bool
 }
 
+// See RFC 4252, section 5.1
+const msgUserAuthSuccess = 52
+
+// See RFC 4252, section 5.4
+const msgUserAuthBanner = 53
+
+type userAuthBannerMsg struct {
+	Message string `sshtype:"53"`
+	// unused, but required to allow message parsing
+	Language string
+}
+
 // See RFC 4256, section 3.2
 const msgUserAuthInfoRequest = 60
 const msgUserAuthInfoResponse = 61
@@ -154,7 +162,7 @@ const msgChannelOpen = 90
 
 type channelOpenMsg struct {
 	ChanType         string `sshtype:"90"`
-	PeersId          uint32
+	PeersID          uint32
 	PeersWindow      uint32
 	MaxPacketSize    uint32
 	TypeSpecificData []byte `ssh:"rest"`
@@ -165,7 +173,7 @@ const msgChannelData = 94
 
 // Used for debug print outs of packets.
 type channelDataMsg struct {
-	PeersId uint32 `sshtype:"94"`
+	PeersID uint32 `sshtype:"94"`
 	Length  uint32
 	Rest    []byte `ssh:"rest"`
 }
@@ -174,8 +182,8 @@ type channelDataMsg struct {
 const msgChannelOpenConfirm = 91
 
 type channelOpenConfirmMsg struct {
-	PeersId          uint32 `sshtype:"91"`
-	MyId             uint32
+	PeersID          uint32 `sshtype:"91"`
+	MyID             uint32
 	MyWindow         uint32
 	MaxPacketSize    uint32
 	TypeSpecificData []byte `ssh:"rest"`
@@ -185,7 +193,7 @@ type channelOpenConfirmMsg struct {
 const msgChannelOpenFailure = 92
 
 type channelOpenFailureMsg struct {
-	PeersId  uint32 `sshtype:"92"`
+	PeersID  uint32 `sshtype:"92"`
 	Reason   RejectionReason
 	Message  string
 	Language string
@@ -194,7 +202,7 @@ type channelOpenFailureMsg struct {
 const msgChannelRequest = 98
 
 type channelRequestMsg struct {
-	PeersId             uint32 `sshtype:"98"`
+	PeersID             uint32 `sshtype:"98"`
 	Request             string
 	WantReply           bool
 	RequestSpecificData []byte `ssh:"rest"`
@@ -204,28 +212,28 @@ type channelRequestMsg struct {
 const msgChannelSuccess = 99
 
 type channelRequestSuccessMsg struct {
-	PeersId uint32 `sshtype:"99"`
+	PeersID uint32 `sshtype:"99"`
 }
 
 // See RFC 4254, section 5.4.
 const msgChannelFailure = 100
 
 type channelRequestFailureMsg struct {
-	PeersId uint32 `sshtype:"100"`
+	PeersID uint32 `sshtype:"100"`
 }
 
 // See RFC 4254, section 5.3
 const msgChannelClose = 97
 
 type channelCloseMsg struct {
-	PeersId uint32 `sshtype:"97"`
+	PeersID uint32 `sshtype:"97"`
 }
 
 // See RFC 4254, section 5.3
 const msgChannelEOF = 96
 
 type channelEOFMsg struct {
-	PeersId uint32 `sshtype:"96"`
+	PeersID uint32 `sshtype:"96"`
 }
 
 // See RFC 4254, section 4
@@ -255,7 +263,7 @@ type globalRequestFailureMsg struct {
 const msgChannelWindowAdjust = 93
 
 type windowAdjustMsg struct {
-	PeersId         uint32 `sshtype:"93"`
+	PeersID         uint32 `sshtype:"93"`
 	AdditionalBytes uint32
 }
 
diff --git a/vendor/golang.org/x/crypto/ssh/mux.go b/vendor/golang.org/x/crypto/ssh/mux.go
index 27a527c..f190162 100644
--- a/vendor/golang.org/x/crypto/ssh/mux.go
+++ b/vendor/golang.org/x/crypto/ssh/mux.go
@@ -278,7 +278,7 @@ func (m *mux) handleChannelOpen(packet []byte) error {
 
 	if msg.MaxPacketSize < minPacketLength || msg.MaxPacketSize > 1<<31 {
 		failMsg := channelOpenFailureMsg{
-			PeersId:  msg.PeersId,
+			PeersID:  msg.PeersID,
 			Reason:   ConnectionFailed,
 			Message:  "invalid request",
 			Language: "en_US.UTF-8",
@@ -287,7 +287,7 @@ func (m *mux) handleChannelOpen(packet []byte) error {
 	}
 
 	c := m.newChannel(msg.ChanType, channelInbound, msg.TypeSpecificData)
-	c.remoteId = msg.PeersId
+	c.remoteId = msg.PeersID
 	c.maxRemotePayload = msg.MaxPacketSize
 	c.remoteWin.add(msg.PeersWindow)
 	m.incomingChannels <- c
@@ -313,7 +313,7 @@ func (m *mux) openChannel(chanType string, extra []byte) (*channel, error) {
 		PeersWindow:      ch.myWindow,
 		MaxPacketSize:    ch.maxIncomingPayload,
 		TypeSpecificData: extra,
-		PeersId:          ch.localId,
+		PeersID:          ch.localId,
 	}
 	if err := m.sendMessage(open); err != nil {
 		return nil, err
diff --git a/vendor/golang.org/x/crypto/ssh/server.go b/vendor/golang.org/x/crypto/ssh/server.go
index 8a78b7c..b83d473 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
@@ -252,7 +256,7 @@ 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
@@ -312,6 +316,7 @@ func (s *connection) serverAuthenticate(config *ServerConfig) (*Permissions, err
 
 	authFailures := 0
 	var authErrs []error
+	var displayedBanner bool
 
 userAuthLoop:
 	for {
@@ -343,6 +348,20 @@ 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")
 
diff --git a/vendor/golang.org/x/crypto/ssh/session.go b/vendor/golang.org/x/crypto/ssh/session.go
index cc06e03..d3321f6 100644
--- a/vendor/golang.org/x/crypto/ssh/session.go
+++ b/vendor/golang.org/x/crypto/ssh/session.go
@@ -406,7 +406,7 @@ func (s *Session) Wait() error {
 		s.stdinPipeWriter.Close()
 	}
 	var copyError error
-	for _ = range s.copyFuncs {
+	for range s.copyFuncs {
 		if err := <-s.errors; err != nil && copyError == nil {
 			copyError = err
 		}
diff --git a/vendor/golang.org/x/crypto/ssh/transport.go b/vendor/golang.org/x/crypto/ssh/transport.go
index f9780e0..01150eb 100644
--- a/vendor/golang.org/x/crypto/ssh/transport.go
+++ b/vendor/golang.org/x/crypto/ssh/transport.go
@@ -76,17 +76,17 @@ type connectionState struct {
 // both directions are triggered by reading and writing a msgNewKey packet
 // respectively.
 func (t *transport) prepareKeyChange(algs *algorithms, kexResult *kexResult) error {
-	if ciph, err := newPacketCipher(t.reader.dir, algs.r, kexResult); err != nil {
+	ciph, err := newPacketCipher(t.reader.dir, algs.r, kexResult)
+	if err != nil {
 		return err
-	} else {
-		t.reader.pendingKeyChange <- ciph
 	}
+	t.reader.pendingKeyChange <- ciph
 
-	if ciph, err := newPacketCipher(t.writer.dir, algs.w, kexResult); err != nil {
+	ciph, err = newPacketCipher(t.writer.dir, algs.w, kexResult)
+	if err != nil {
 		return err
-	} else {
-		t.writer.pendingKeyChange <- ciph
 	}
+	t.writer.pendingKeyChange <- ciph
 
 	return nil
 }
@@ -139,7 +139,7 @@ func (s *connectionState) readPacket(r *bufio.Reader) ([]byte, error) {
 			case cipher := <-s.pendingKeyChange:
 				s.packetCipher = cipher
 			default:
-				return nil, errors.New("ssh: got bogus newkeys message.")
+				return nil, errors.New("ssh: got bogus newkeys message")
 			}
 
 		case msgDisconnect:
@@ -254,7 +254,7 @@ func newPacketCipher(d direction, algs directionAlgorithms, kex *kexResult) (pac
 	iv, key, macKey := generateKeys(d, algs, kex)
 
 	if algs.Cipher == gcmCipherID {
-		return newGCMCipher(iv, key, macKey)
+		return newGCMCipher(iv, key)
 	}
 
 	if algs.Cipher == aes128cbcID {
diff --git a/vendor/vendor.json b/vendor/vendor.json
index f42f7c2..a0c69df 100644
--- a/vendor/vendor.json
+++ b/vendor/vendor.json
@@ -20,6 +20,12 @@
 			"revision": "7a41df006ff9af79a29f0ffa9c5f21fbe6314a2d",
 			"revisionTime": "2017-01-10T07:11:07Z"
 		},
+		{
+			"checksumSHA1": "XIIHyP5QkRbX/zBNqq+hAQ2SmzE=",
+			"path": "github.com/gliderlabs/ssh",
+			"revision": "ce31f3cc47feee0c38db7ecfaa154026929ffbda",
+			"revisionTime": "2017-12-06T20:46:25Z"
+		},
 		{
 			"checksumSHA1": "fI9spYCCgBl19GMD/JsW+znBHkw=",
 			"path": "github.com/go-gormigrate/gormigrate",
@@ -107,26 +113,26 @@
 		{
 			"checksumSHA1": "IQkUIOnvlf0tYloFx9mLaXSvXWQ=",
 			"path": "golang.org/x/crypto/curve25519",
-			"revision": "bd6f299fb381e4c3393d1c4b1f0b94f5e77650c8",
-			"revisionTime": "2017-10-31T10:16:35Z"
+			"revision": "d585fd2cc9195196078f516b69daff6744ef5e84",
+			"revisionTime": "2017-12-16T04:08:15Z"
 		},
 		{
 			"checksumSHA1": "1hwn8cgg4EVXhCpJIqmMbzqnUo0=",
 			"path": "golang.org/x/crypto/ed25519",
-			"revision": "bd6f299fb381e4c3393d1c4b1f0b94f5e77650c8",
-			"revisionTime": "2017-10-31T10:16:35Z"
+			"revision": "d585fd2cc9195196078f516b69daff6744ef5e84",
+			"revisionTime": "2017-12-16T04:08:15Z"
 		},
 		{
 			"checksumSHA1": "LXFcVx8I587SnWmKycSDEq9yvK8=",
 			"path": "golang.org/x/crypto/ed25519/internal/edwards25519",
-			"revision": "bd6f299fb381e4c3393d1c4b1f0b94f5e77650c8",
-			"revisionTime": "2017-10-31T10:16:35Z"
+			"revision": "d585fd2cc9195196078f516b69daff6744ef5e84",
+			"revisionTime": "2017-12-16T04:08:15Z"
 		},
 		{
-			"checksumSHA1": "EGImhmIP401D+CChQfTscz2RuGE=",
+			"checksumSHA1": "pySTR3iSeU7FhjbBnQPNxgyIa4I=",
 			"path": "golang.org/x/crypto/ssh",
-			"revision": "bd6f299fb381e4c3393d1c4b1f0b94f5e77650c8",
-			"revisionTime": "2017-10-31T10:16:35Z"
+			"revision": "d585fd2cc9195196078f516b69daff6744ef5e84",
+			"revisionTime": "2017-12-16T04:08:15Z"
 		},
 		{
 			"checksumSHA1": "nqWNlnMmVpt628zzvyo6Yv2CX5Q=",