switch to use gliderlabs/ssh for builtin server (#7250)

resolves git conflicts from #3896 (credit to @belak, in case github doesn't keep original author during squash)

Co-Authored-By: Matti Ranta <techknowlogick@gitea.io>

go.mod

@@ -40,7 +40,7 @@ require (
 	github.com/facebookgo/stack v0.0.0-20160209184415-751773369052 // indirect
 	github.com/facebookgo/stats v0.0.0-20151006221625-1b76add642e4 // indirect
 	github.com/facebookgo/subset v0.0.0-20150612182917-8dac2c3c4870 // indirect
-	github.com/gliderlabs/ssh v0.1.4 // indirect
+	github.com/gliderlabs/ssh v0.2.2
 	github.com/glycerine/go-unsnap-stream v0.0.0-20180323001048-9f0cb55181dd // indirect
 	github.com/glycerine/goconvey v0.0.0-20190315024820-982ee783a72e // indirect
 	github.com/go-macaron/binding v0.0.0-20160711225916-9440f336b443
@@ -110,11 +110,11 @@ require (
 	github.com/yohcop/openid-go v0.0.0-20160914080427-2c050d2dae53
 	go.etcd.io/bbolt v1.3.2 // indirect
 	golang.org/x/crypto v0.0.0-20190618222545-ea8f1a30c443
-	golang.org/x/net v0.0.0-20190613194153-d28f0bde5980
+	golang.org/x/net v0.0.0-20190619014844-b5b0513f8c1b
 	golang.org/x/oauth2 v0.0.0-20181101160152-c453e0c75759
-	golang.org/x/sys v0.0.0-20190618155005-516e3c20635f
+	golang.org/x/sys v0.0.0-20190620070143-6f217b454f45
 	golang.org/x/text v0.3.2
-	golang.org/x/tools v0.0.0-20190618163018-fdf1049a943a // indirect
+	golang.org/x/tools v0.0.0-20190620154339-431033348dd0 // indirect
 	gopkg.in/alexcesaro/quotedprintable.v3 v3.0.0-20150716171945-2caba252f4dc // indirect
 	gopkg.in/asn1-ber.v1 v1.0.0-20150924051756-4e86f4367175 // indirect
 	gopkg.in/bufio.v1 v1.0.0-20140618132640-567b2bfa514e // indirect

go.sum

@@ -100,8 +100,8 @@ github.com/flynn/go-shlex v0.0.0-20150515145356-3f9db97f8568/go.mod h1:xEzjJPgXI
 github.com/fsnotify/fsnotify v1.4.7 h1:IXs+QLmnXW2CcXuY+8Mzv/fWEsPGWxqefPtCP5CnV9I=
 github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
 github.com/gliderlabs/ssh v0.1.3/go.mod h1:U7qILu1NlMHj9FlMhZLlkCdDnU1DBEAqr0aevW3Awn0=
-github.com/gliderlabs/ssh v0.1.4 h1:5N8AYXpaQAPy0L7linKa5aI+WRfyYagAhjksVzxh+mI=
+github.com/gliderlabs/ssh v0.2.2 h1:6zsha5zo/TWhRhwqCD3+EarCAgZ2yN28ipRnGPnwkI0=
-github.com/gliderlabs/ssh v0.1.4/go.mod h1:U7qILu1NlMHj9FlMhZLlkCdDnU1DBEAqr0aevW3Awn0=
+github.com/gliderlabs/ssh v0.2.2/go.mod h1:U7qILu1NlMHj9FlMhZLlkCdDnU1DBEAqr0aevW3Awn0=
 github.com/glycerine/go-unsnap-stream v0.0.0-20180323001048-9f0cb55181dd h1:r04MMPyLHj/QwZuMJ5+7tJcBr1AQjpiAK/rZWRrQT7o=
 github.com/glycerine/go-unsnap-stream v0.0.0-20180323001048-9f0cb55181dd/go.mod h1:/20jfyN9Y5QPEAprSgKAUr+glWDY39ZiUEAYOEv5dsE=
 github.com/glycerine/goconvey v0.0.0-20190315024820-982ee783a72e h1:SiEs4J3BKVIeaWrH3tKaz3QLZhJ68iJ/A4xrzIoE5+Y=
@@ -369,8 +369,8 @@ golang.org/x/net v0.0.0-20181114220301-adae6a3d119a/go.mod h1:mL1N/T3taQHkDXs73r
 golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190502183928-7f726cade0ab/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
-golang.org/x/net v0.0.0-20190613194153-d28f0bde5980 h1:dfGZHvZk057jK2MCeWus/TowKpJ8y4AmooUzdBSR9GU=
+golang.org/x/net v0.0.0-20190619014844-b5b0513f8c1b h1:lkjdUzSyJ5P1+eal9fxXX9Xg2BTfswsonKUse48C0uE=
-golang.org/x/net v0.0.0-20190613194153-d28f0bde5980/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20190619014844-b5b0513f8c1b/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/oauth2 v0.0.0-20180620175406-ef147856a6dd/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/oauth2 v0.0.0-20181101160152-c453e0c75759 h1:TMrx+Qdx7uJAeUbv15N72h5Hmyb5+VDjEiMufAEAM04=
@@ -395,15 +395,15 @@ golang.org/x/sys v0.0.0-20190403152447-81d4e9dc473e h1:nFYrTHrdrAOpShe27kaFHjsqY
 golang.org/x/sys v0.0.0-20190403152447-81d4e9dc473e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190422165155-953cdadca894/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20190618155005-516e3c20635f h1:dHNZYIYdq2QuU6w73vZ/DzesPbVlZVYZTtTZmrnsbQ8=
+golang.org/x/sys v0.0.0-20190620070143-6f217b454f45 h1:Dl2hc890lrizvUppGbRWhnIh2f8jOTCQpY5IKWRS0oM=
-golang.org/x/sys v0.0.0-20190618155005-516e3c20635f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20190620070143-6f217b454f45/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.2 h1:tW2bmiBqwgJj/UpqtC8EpXEZVYOwU0yG4iWbprSVAcs=
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
-golang.org/x/tools v0.0.0-20190618163018-fdf1049a943a h1:aQmaYPOmKItb96VioBrTlYay5tSNUdKAFEhPCWMeLSM=
+golang.org/x/tools v0.0.0-20190620154339-431033348dd0 h1:qUGDNmGEM+ZBtwF9vuzEv+9nQQPL+l/oNBZ+DCDTAyo=
-golang.org/x/tools v0.0.0-20190618163018-fdf1049a943a/go.mod h1:/rFqwRUd4F7ZHNgwSSTFct+R/Kf4OFW1sUzUTQQTgfc=
+golang.org/x/tools v0.0.0-20190620154339-431033348dd0/go.mod h1:/rFqwRUd4F7ZHNgwSSTFct+R/Kf4OFW1sUzUTQQTgfc=
 google.golang.org/appengine v1.1.0/go.mod h1:EbEs0AVv82hx2wNQdGPgUI5lhzA/G0D9YwlJXL52JkM=
 google.golang.org/appengine v1.2.0 h1:S0iUepdCWODXRvtE+gcRDd15L+k+k1AiHlMiMjefH24=
 google.golang.org/appengine v1.2.0/go.mod h1:xpcJRLb0r/rnEns0DIKYYv+WjYCduHsrkT7/EB5XEv4=

integrations/mssql.ini.tmpl

@@ -34,6 +34,7 @@ LFS_CONTENT_PATH = data/lfs-mssql
 OFFLINE_MODE     = false
 LFS_JWT_SECRET   = Tv_MjmZuHqpIY6GFl12ebgkRAMt4RlWt0v4EHKSXO0w
 APP_DATA_PATH    = integrations/gitea-integration-mssql/data
+BUILTIN_SSH_SERVER_USER = git
 
 [mailer]
 ENABLED = true

integrations/mysql.ini.tmpl

@@ -34,6 +34,7 @@ LFS_CONTENT_PATH = data/lfs-mysql
 OFFLINE_MODE     = false
 LFS_JWT_SECRET   = Tv_MjmZuHqpIY6GFl12ebgkRAMt4RlWt0v4EHKSXO0w
 APP_DATA_PATH    = integrations/gitea-integration-mysql/data
+BUILTIN_SSH_SERVER_USER = git
 
 [mailer]
 ENABLED = true

integrations/mysql8.ini.tmpl

@@ -34,6 +34,7 @@ LFS_CONTENT_PATH = data/lfs-mysql8
 OFFLINE_MODE     = false
 LFS_JWT_SECRET   = Tv_MjmZuHqpIY6GFl12ebgkRAMt4RlWt0v4EHKSXO0w
 APP_DATA_PATH    = integrations/gitea-integration-mysql8/data
+BUILTIN_SSH_SERVER_USER = git
 
 [mailer]
 ENABLED = false

integrations/pgsql.ini.tmpl

@@ -34,6 +34,7 @@ LFS_CONTENT_PATH = data/lfs-pgsql
 OFFLINE_MODE     = false
 LFS_JWT_SECRET   = Tv_MjmZuHqpIY6GFl12ebgkRAMt4RlWt0v4EHKSXO0w
 APP_DATA_PATH    = integrations/gitea-integration-pgsql/data
+BUILTIN_SSH_SERVER_USER = git
 
 [mailer]
 ENABLED = true

integrations/repo_test.go

@@ -73,7 +73,7 @@ func TestViewRepo1CloneLinkAuthorized(t *testing.T) {
 	assert.Equal(t, setting.AppURL+"user2/repo1.git", link)
 	link, exists = htmlDoc.doc.Find("#repo-clone-ssh").Attr("data-link")
 	assert.True(t, exists, "The template has changed")
-	sshURL := fmt.Sprintf("ssh://%s@%s:%d/user2/repo1.git", setting.RunUser, setting.SSH.Domain, setting.SSH.Port)
+	sshURL := fmt.Sprintf("ssh://%s@%s:%d/user2/repo1.git", setting.SSH.BuiltinServerUser, setting.SSH.Domain, setting.SSH.Port)
 	assert.Equal(t, sshURL, link)
 }
 

integrations/sqlite.ini

@@ -31,6 +31,7 @@ OFFLINE_MODE     = false
 LFS_JWT_SECRET   = Tv_MjmZuHqpIY6GFl12ebgkRAMt4RlWt0v4EHKSXO0w
 APP_DATA_PATH    = integrations/gitea-integration-sqlite/data
 ENABLE_GZIP      = true
+BUILTIN_SSH_SERVER_USER = git
 
 [mailer]
 ENABLED     = true

modules/ssh/ssh.go

@@ -1,4 +1,3 @@
-// Copyright 2014 The Gogs Authors. All rights reserved.
 // Copyright 2017 The Gitea Authors. All rights reserved.
 // Use of this source code is governed by a MIT-style
 // license that can be found in the LICENSE file.
@@ -10,178 +9,157 @@ import (
 	"crypto/rsa"
 	"crypto/x509"
 	"encoding/pem"
+	"fmt"
 	"io"
-	"io/ioutil"
-	"net"
 	"os"
 	"os/exec"
 	"path/filepath"
 	"strings"
-
+	"sync"
-	"github.com/Unknwon/com"
+	"syscall"
-	"golang.org/x/crypto/ssh"
 
 	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
+
+	"github.com/Unknwon/com"
+	"github.com/gliderlabs/ssh"
+	gossh "golang.org/x/crypto/ssh"
 )
 
-func cleanCommand(cmd string) string {
+type contextKey string
-	i := strings.Index(cmd, "git")
-	if i == -1 {
-		return cmd
-	}
-	return cmd[i:]
-}
 
-func handleServerConn(keyID string, chans <-chan ssh.NewChannel) {
+const giteaKeyID = contextKey("gitea-key-id")
-	for newChan := range chans {
+
-		if newChan.ChannelType() != "session" {
+func getExitStatusFromError(err error) int {
-			err := newChan.Reject(ssh.UnknownChannelType, "unknown channel type")
+	if err == nil {
-			if err != nil {
+		return 0
-				log.Error("Error rejecting channel: %v", err)
+	}
-			}
+
-			continue
+	exitErr, ok := err.(*exec.ExitError)
+	if !ok {
+		return 1
+	}
+
+	waitStatus, ok := exitErr.Sys().(syscall.WaitStatus)
+	if !ok {
+		// This is a fallback and should at least let us return something useful
+		// when running on Windows, even if it isn't completely accurate.
+		if exitErr.Success() {
+			return 0
 		}
 
-		ch, reqs, err := newChan.Accept()
+		return 1
-		if err != nil {
-			log.Error("Error accepting channel: %v", err)
-			continue
-		}
-
-		go func(in <-chan *ssh.Request) {
-			defer func() {
-				if err = ch.Close(); err != nil {
-					log.Error("Close: %v", err)
-				}
-			}()
-			for req := range in {
-				payload := cleanCommand(string(req.Payload))
-				switch req.Type {
-				case "exec":
-					cmdName := strings.TrimLeft(payload, "'()")
-					log.Trace("SSH: Payload: %v", cmdName)
-
-					args := []string{"serv", "key-" + keyID, "--config=" + setting.CustomConf}
-					log.Trace("SSH: Arguments: %v", args)
-					cmd := exec.Command(setting.AppPath, args...)
-					cmd.Env = append(
-						os.Environ(),
-						"SSH_ORIGINAL_COMMAND="+cmdName,
-						"SKIP_MINWINSVC=1",
-					)
-
-					stdout, err := cmd.StdoutPipe()
-					if err != nil {
-						log.Error("SSH: StdoutPipe: %v", err)
-						return
-					}
-					stderr, err := cmd.StderrPipe()
-					if err != nil {
-						log.Error("SSH: StderrPipe: %v", err)
-						return
-					}
-					input, err := cmd.StdinPipe()
-					if err != nil {
-						log.Error("SSH: StdinPipe: %v", err)
-						return
-					}
-
-					// FIXME: check timeout
-					if err = cmd.Start(); err != nil {
-						log.Error("SSH: Start: %v", err)
-						return
-					}
-
-					err = req.Reply(true, nil)
-					if err != nil {
-						log.Error("SSH: Reply: %v", err)
-					}
-					go func() {
-						_, err = io.Copy(input, ch)
-						if err != nil {
-							log.Error("SSH: Copy: %v", err)
-						}
-					}()
-					_, err = io.Copy(ch, stdout)
-					if err != nil {
-						log.Error("SSH: Copy: %v", err)
-					}
-					_, err = io.Copy(ch.Stderr(), stderr)
-					if err != nil {
-						log.Error("SSH: Copy: %v", err)
-					}
-
-					if err = cmd.Wait(); err != nil {
-						log.Error("SSH: Wait: %v", err)
-						return
-					}
-
-					_, err = ch.SendRequest("exit-status", false, []byte{0, 0, 0, 0})
-					if err != nil {
-						log.Error("SSH: SendRequest: %v", err)
-					}
-					return
-				default:
-				}
-			}
-		}(reqs)
 	}
+
+	return waitStatus.ExitStatus()
 }
 
-func listen(config *ssh.ServerConfig, host string, port int) {
+func sessionHandler(session ssh.Session) {
-	listener, err := net.Listen("tcp", host+":"+com.ToStr(port))
+	keyID := session.Context().Value(giteaKeyID).(int64)
+
+	command := session.RawCommand()
+
+	log.Trace("SSH: Payload: %v", command)
+
+	args := []string{"serv", "key-" + com.ToStr(keyID), "--config=" + setting.CustomConf}
+	log.Trace("SSH: Arguments: %v", args)
+	cmd := exec.Command(setting.AppPath, args...)
+	cmd.Env = append(
+		os.Environ(),
+		"SSH_ORIGINAL_COMMAND="+command,
+		"SKIP_MINWINSVC=1",
+	)
+
+	stdout, err := cmd.StdoutPipe()
 	if err != nil {
-		log.Fatal("Failed to start SSH server: %v", err)
+		log.Error("SSH: StdoutPipe: %v", err)
+		return
 	}
-	for {
+	stderr, err := cmd.StderrPipe()
-		// Once a ServerConfig has been configured, connections can be accepted.
+	if err != nil {
-		conn, err := listener.Accept()
+		log.Error("SSH: StderrPipe: %v", err)
-		if err != nil {
+		return
-			log.Error("SSH: Error accepting incoming connection: %v", err)
+	}
-			continue
+	stdin, err := cmd.StdinPipe()
+	if err != nil {
+		log.Error("SSH: StdinPipe: %v", err)
+		return
+	}
+
+	wg := &sync.WaitGroup{}
+	wg.Add(2)
+
+	if err = cmd.Start(); err != nil {
+		log.Error("SSH: Start: %v", err)
+		return
+	}
+
+	go func() {
+		defer stdin.Close()
+		if _, err := io.Copy(stdin, session); err != nil {
+			log.Error("Failed to write session to stdin. %s", err)
 		}
+	}()
 
-		// Before use, a handshake must be performed on the incoming net.Conn.
+	go func() {
-		// It must be handled in a separate goroutine,
+		defer wg.Done()
-		// otherwise one user could easily block entire loop.
+		if _, err := io.Copy(session, stdout); err != nil {
-		// For example, user could be asked to trust server key fingerprint and hangs.
+			log.Error("Failed to write stdout to session. %s", err)
-		go func() {
+		}
-			log.Trace("SSH: Handshaking for %s", conn.RemoteAddr())
+	}()
-			sConn, chans, reqs, err := ssh.NewServerConn(conn, config)
-			if err != nil {
-				if err == io.EOF {
-					log.Warn("SSH: Handshaking with %s was terminated: %v", conn.RemoteAddr(), err)
-				} else {
-					log.Error("SSH: Error on handshaking with %s: %v", conn.RemoteAddr(), err)
-				}
-				return
-			}
 
-			log.Trace("SSH: Connection from %s (%s)", sConn.RemoteAddr(), sConn.ClientVersion())
+	go func() {
-			// The incoming Request channel must be serviced.
+		defer wg.Done()
-			go ssh.DiscardRequests(reqs)
+		if _, err := io.Copy(session.Stderr(), stderr); err != nil {
-			go handleServerConn(sConn.Permissions.Extensions["key-id"], chans)
+			log.Error("Failed to write stderr to session. %s", err)
-		}()
+		}
+	}()
+
+	// Ensure all the output has been written before we wait on the command
+	// to exit.
+	wg.Wait()
+
+	// Wait for the command to exit and log any errors we get
+	err = cmd.Wait()
+	if err != nil {
+		log.Error("SSH: Wait: %v", err)
 	}
+
+	if err := session.Exit(getExitStatusFromError(err)); err != nil {
+		log.Error("Session failed to exit. %s", err)
+	}
+}
+
+func publicKeyHandler(ctx ssh.Context, key ssh.PublicKey) bool {
+	if ctx.User() != setting.SSH.BuiltinServerUser {
+		return false
+	}
+
+	pkey, err := models.SearchPublicKeyByContent(strings.TrimSpace(string(gossh.MarshalAuthorizedKey(key))))
+	if err != nil {
+		log.Error("SearchPublicKeyByContent: %v", err)
+		return false
+	}
+
+	ctx.SetValue(giteaKeyID, pkey.ID)
+
+	return true
 }
 
 // Listen starts a SSH server listens on given port.
 func Listen(host string, port int, ciphers []string, keyExchanges []string, macs []string) {
-	config := &ssh.ServerConfig{
+	// TODO: Handle ciphers, keyExchanges, and macs
-		Config: ssh.Config{
+
-			Ciphers:      ciphers,
+	srv := ssh.Server{
-			KeyExchanges: keyExchanges,
+		Addr:             fmt.Sprintf("%s:%d", host, port),
-			MACs:         macs,
+		PublicKeyHandler: publicKeyHandler,
-		},
+		Handler:          sessionHandler,
-		PublicKeyCallback: func(conn ssh.ConnMetadata, key ssh.PublicKey) (*ssh.Permissions, error) {
+
-			pkey, err := models.SearchPublicKeyByContent(strings.TrimSpace(string(ssh.MarshalAuthorizedKey(key))))
+		// We need to explicitly disable the PtyCallback so text displays
-			if err != nil {
+		// properly.
-				log.Error("SearchPublicKeyByContent: %v", err)
+		PtyCallback: func(ctx ssh.Context, pty ssh.Pty) bool {
-				return nil, err
+			return false
-			}
-			return &ssh.Permissions{Extensions: map[string]string{"key-id": com.ToStr(pkey.ID)}}, nil
 		},
 	}
 
@@ -197,20 +175,21 @@ func Listen(host string, port int, ciphers []string, keyExchanges []string, macs
 		if err != nil {
 			log.Fatal("Failed to generate private key: %v", err)
 		}
-		log.Trace("SSH: New private key is generateed: %s", keyPath)
+		log.Trace("New private key is generated: %s", keyPath)
 	}
 
-	privateBytes, err := ioutil.ReadFile(keyPath)
+	err := srv.SetOption(ssh.HostKeyFile(keyPath))
 	if err != nil {
-		log.Fatal("SSH: Failed to load private key")
+		log.Error("Failed to set Host Key. %s", err)
 	}
-	private, err := ssh.ParsePrivateKey(privateBytes)
-	if err != nil {
-		log.Fatal("SSH: Failed to parse private key")
-	}
-	config.AddHostKey(private)
 
-	go listen(config, host, port)
+	go func() {
+		err := srv.ListenAndServe()
+		if err != nil {
+			log.Error("Failed to serve with builtin SSH server. %s", err)
+		}
+	}()
+
 }
 
 // GenKeyPair make a pair of public and private keys for SSH access.
@@ -238,12 +217,12 @@ func GenKeyPair(keyPath string) error {
 	}
 
 	// generate public key
-	pub, err := ssh.NewPublicKey(&privateKey.PublicKey)
+	pub, err := gossh.NewPublicKey(&privateKey.PublicKey)
 	if err != nil {
 		return err
 	}
 
-	public := ssh.MarshalAuthorizedKey(pub)
+	public := gossh.MarshalAuthorizedKey(pub)
 	p, err := os.OpenFile(keyPath+".pub", os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0600)
 	if err != nil {
 		return err

vendor/github.com/anmitsu/go-shlex/.gitignore

@@ -0,0 +1 @@
+shlex.test

vendor/github.com/anmitsu/go-shlex/LICENSE

@@ -0,0 +1,20 @@
+Copyright (c) anmitsu <anmitsu.s@gmail.com>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

vendor/github.com/anmitsu/go-shlex/README.md

@@ -0,0 +1,38 @@
+# go-shlex
+
+go-shlex is a library to make a lexical analyzer like Unix shell for
+Go.
+
+## Install
+
+    go get -u "github.com/anmitsu/go-shlex"
+
+## Usage
+
+```go
+package main
+
+import (
+    "fmt"
+    "log"
+
+    "github.com/anmitsu/go-shlex"
+)
+
+func main() {
+    cmd := `cp -Rdp "file name" 'file name2' dir\ name`
+    words, err := shlex.Split(cmd, true)
+    if err != nil {
+        log.Fatal(err)
+    }
+
+    for _, w := range words {
+        fmt.Println(w)
+    }
+}
+```
+
+## Documentation
+
+http://godoc.org/github.com/anmitsu/go-shlex
+

vendor/github.com/anmitsu/go-shlex/shlex.go

@@ -0,0 +1,193 @@
+// Package shlex provides a simple lexical analysis like Unix shell.
+package shlex
+
+import (
+	"bufio"
+	"errors"
+	"io"
+	"strings"
+	"unicode"
+)
+
+var (
+	ErrNoClosing = errors.New("No closing quotation")
+	ErrNoEscaped = errors.New("No escaped character")
+)
+
+// Tokenizer is the interface that classifies a token according to
+// words, whitespaces, quotations, escapes and escaped quotations.
+type Tokenizer interface {
+	IsWord(rune) bool
+	IsWhitespace(rune) bool
+	IsQuote(rune) bool
+	IsEscape(rune) bool
+	IsEscapedQuote(rune) bool
+}
+
+// DefaultTokenizer implements a simple tokenizer like Unix shell.
+type DefaultTokenizer struct{}
+
+func (t *DefaultTokenizer) IsWord(r rune) bool {
+	return r == '_' || unicode.IsLetter(r) || unicode.IsNumber(r)
+}
+func (t *DefaultTokenizer) IsQuote(r rune) bool {
+	switch r {
+	case '\'', '"':
+		return true
+	default:
+		return false
+	}
+}
+func (t *DefaultTokenizer) IsWhitespace(r rune) bool {
+	return unicode.IsSpace(r)
+}
+func (t *DefaultTokenizer) IsEscape(r rune) bool {
+	return r == '\\'
+}
+func (t *DefaultTokenizer) IsEscapedQuote(r rune) bool {
+	return r == '"'
+}
+
+// Lexer represents a lexical analyzer.
+type Lexer struct {
+	reader          *bufio.Reader
+	tokenizer       Tokenizer
+	posix           bool
+	whitespacesplit bool
+}
+
+// NewLexer creates a new Lexer reading from io.Reader.  This Lexer
+// has a DefaultTokenizer according to posix and whitespacesplit
+// rules.
+func NewLexer(r io.Reader, posix, whitespacesplit bool) *Lexer {
+	return &Lexer{
+		reader:          bufio.NewReader(r),
+		tokenizer:       &DefaultTokenizer{},
+		posix:           posix,
+		whitespacesplit: whitespacesplit,
+	}
+}
+
+// NewLexerString creates a new Lexer reading from a string.  This
+// Lexer has a DefaultTokenizer according to posix and whitespacesplit
+// rules.
+func NewLexerString(s string, posix, whitespacesplit bool) *Lexer {
+	return NewLexer(strings.NewReader(s), posix, whitespacesplit)
+}
+
+// Split splits a string according to posix or non-posix rules.
+func Split(s string, posix bool) ([]string, error) {
+	return NewLexerString(s, posix, true).Split()
+}
+
+// SetTokenizer sets a Tokenizer.
+func (l *Lexer) SetTokenizer(t Tokenizer) {
+	l.tokenizer = t
+}
+
+func (l *Lexer) Split() ([]string, error) {
+	result := make([]string, 0)
+	for {
+		token, err := l.readToken()
+		if token != "" {
+			result = append(result, token)
+		}
+
+		if err == io.EOF {
+			break
+		} else if err != nil {
+			return result, err
+		}
+	}
+	return result, nil
+}
+
+func (l *Lexer) readToken() (string, error) {
+	t := l.tokenizer
+	token := ""
+	quoted := false
+	state := ' '
+	escapedstate := ' '
+scanning:
+	for {
+		next, _, err := l.reader.ReadRune()
+		if err != nil {
+			if t.IsQuote(state) {
+				return token, ErrNoClosing
+			} else if t.IsEscape(state) {
+				return token, ErrNoEscaped
+			}
+			return token, err
+		}
+
+		switch {
+		case t.IsWhitespace(state):
+			switch {
+			case t.IsWhitespace(next):
+				break scanning
+			case l.posix && t.IsEscape(next):
+				escapedstate = 'a'
+				state = next
+			case t.IsWord(next):
+				token += string(next)
+				state = 'a'
+			case t.IsQuote(next):
+				if !l.posix {
+					token += string(next)
+				}
+				state = next
+			default:
+				token = string(next)
+				if l.whitespacesplit {
+					state = 'a'
+				} else if token != "" || (l.posix && quoted) {
+					break scanning
+				}
+			}
+		case t.IsQuote(state):
+			quoted = true
+			switch {
+			case next == state:
+				if !l.posix {
+					token += string(next)
+					break scanning
+				} else {
+					state = 'a'
+				}
+			case l.posix && t.IsEscape(next) && t.IsEscapedQuote(state):
+				escapedstate = state
+				state = next
+			default:
+				token += string(next)
+			}
+		case t.IsEscape(state):
+			if t.IsQuote(escapedstate) && next != state && next != escapedstate {
+				token += string(state)
+			}
+			token += string(next)
+			state = escapedstate
+		case t.IsWord(state):
+			switch {
+			case t.IsWhitespace(next):
+				if token != "" || (l.posix && quoted) {
+					break scanning
+				}
+			case l.posix && t.IsQuote(next):
+				state = next
+			case l.posix && t.IsEscape(next):
+				escapedstate = 'a'
+				state = next
+			case t.IsWord(next) || t.IsQuote(next):
+				token += string(next)
+			default:
+				if l.whitespacesplit {
+					token += string(next)
+				} else if token != "" {
+					l.reader.UnreadRune()
+					break scanning
+				}
+			}
+		}
+	}
+	return token, nil
+}

vendor/github.com/gliderlabs/ssh/LICENSE

@@ -0,0 +1,27 @@
+Copyright (c) 2016 Glider Labs. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Glider Labs nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

vendor/github.com/gliderlabs/ssh/README.md

@@ -0,0 +1,96 @@
+# gliderlabs/ssh
+
+[![GoDoc](https://godoc.org/github.com/gliderlabs/ssh?status.svg)](https://godoc.org/github.com/gliderlabs/ssh) 
+[![CircleCI](https://img.shields.io/circleci/project/github/gliderlabs/ssh.svg)](https://circleci.com/gh/gliderlabs/ssh)
+[![Go Report Card](https://goreportcard.com/badge/github.com/gliderlabs/ssh)](https://goreportcard.com/report/github.com/gliderlabs/ssh) 
+[![OpenCollective](https://opencollective.com/ssh/sponsors/badge.svg)](#sponsors)
+[![Slack](http://slack.gliderlabs.com/badge.svg)](http://slack.gliderlabs.com) 
+[![Email Updates](https://img.shields.io/badge/updates-subscribe-yellow.svg)](https://app.convertkit.com/landing_pages/243312)
+
+> The Glider Labs SSH server package is dope.  —[@bradfitz](https://twitter.com/bradfitz), Go team member
+
+This Go package wraps the [crypto/ssh
+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 (
+     "github.com/gliderlabs/ssh"
+     "io"
+     "log"
+ )
+
+ func main() {
+     ssh.Handle(func(s ssh.Session) {
+         io.WriteString(s, "Hello world\n")
+     })  
+
+     log.Fatal(ssh.ListenAndServe(":2222", nil))
+ }
+
+```
+This package was built by [@progrium](https://twitter.com/progrium) after working on nearly a dozen projects at Glider Labs using SSH and collaborating with [@shazow](https://twitter.com/shazow) (known for [ssh-chat](https://github.com/shazow/ssh-chat)).
+
+## Examples
+
+A bunch of great examples are in the `_examples` directory.
+
+## Usage
+
+[See GoDoc reference.](https://godoc.org/github.com/gliderlabs/ssh)
+
+## Contributing
+
+Pull requests are welcome! However, since this project is very much about API
+design, please submit API changes as issues to discuss before submitting PRs.
+
+Also, you can [join our Slack](http://slack.gliderlabs.com) to discuss as well.
+
+## Roadmap
+
+* Non-session channel handlers
+* Cleanup callback API
+* 1.0 release
+* High-level client?
+
+## Sponsors
+
+Become a sponsor and get your logo on our README on Github with a link to your site. [[Become a sponsor](https://opencollective.com/ssh#sponsor)]
+
+<a href="https://opencollective.com/ssh/sponsor/0/website" target="_blank"><img src="https://opencollective.com/ssh/sponsor/0/avatar.svg"></a>
+<a href="https://opencollective.com/ssh/sponsor/1/website" target="_blank"><img src="https://opencollective.com/ssh/sponsor/1/avatar.svg"></a>
+<a href="https://opencollective.com/ssh/sponsor/2/website" target="_blank"><img src="https://opencollective.com/ssh/sponsor/2/avatar.svg"></a>
+<a href="https://opencollective.com/ssh/sponsor/3/website" target="_blank"><img src="https://opencollective.com/ssh/sponsor/3/avatar.svg"></a>
+<a href="https://opencollective.com/ssh/sponsor/4/website" target="_blank"><img src="https://opencollective.com/ssh/sponsor/4/avatar.svg"></a>
+<a href="https://opencollective.com/ssh/sponsor/5/website" target="_blank"><img src="https://opencollective.com/ssh/sponsor/5/avatar.svg"></a>
+<a href="https://opencollective.com/ssh/sponsor/6/website" target="_blank"><img src="https://opencollective.com/ssh/sponsor/6/avatar.svg"></a>
+<a href="https://opencollective.com/ssh/sponsor/7/website" target="_blank"><img src="https://opencollective.com/ssh/sponsor/7/avatar.svg"></a>
+<a href="https://opencollective.com/ssh/sponsor/8/website" target="_blank"><img src="https://opencollective.com/ssh/sponsor/8/avatar.svg"></a>
+<a href="https://opencollective.com/ssh/sponsor/9/website" target="_blank"><img src="https://opencollective.com/ssh/sponsor/9/avatar.svg"></a>
+<a href="https://opencollective.com/ssh/sponsor/10/website" target="_blank"><img src="https://opencollective.com/ssh/sponsor/10/avatar.svg"></a>
+<a href="https://opencollective.com/ssh/sponsor/11/website" target="_blank"><img src="https://opencollective.com/ssh/sponsor/11/avatar.svg"></a>
+<a href="https://opencollective.com/ssh/sponsor/12/website" target="_blank"><img src="https://opencollective.com/ssh/sponsor/12/avatar.svg"></a>
+<a href="https://opencollective.com/ssh/sponsor/13/website" target="_blank"><img src="https://opencollective.com/ssh/sponsor/13/avatar.svg"></a>
+<a href="https://opencollective.com/ssh/sponsor/14/website" target="_blank"><img src="https://opencollective.com/ssh/sponsor/14/avatar.svg"></a>
+<a href="https://opencollective.com/ssh/sponsor/15/website" target="_blank"><img src="https://opencollective.com/ssh/sponsor/15/avatar.svg"></a>
+<a href="https://opencollective.com/ssh/sponsor/16/website" target="_blank"><img src="https://opencollective.com/ssh/sponsor/16/avatar.svg"></a>
+<a href="https://opencollective.com/ssh/sponsor/17/website" target="_blank"><img src="https://opencollective.com/ssh/sponsor/17/avatar.svg"></a>
+<a href="https://opencollective.com/ssh/sponsor/18/website" target="_blank"><img src="https://opencollective.com/ssh/sponsor/18/avatar.svg"></a>
+<a href="https://opencollective.com/ssh/sponsor/19/website" target="_blank"><img src="https://opencollective.com/ssh/sponsor/19/avatar.svg"></a>
+<a href="https://opencollective.com/ssh/sponsor/20/website" target="_blank"><img src="https://opencollective.com/ssh/sponsor/20/avatar.svg"></a>
+<a href="https://opencollective.com/ssh/sponsor/21/website" target="_blank"><img src="https://opencollective.com/ssh/sponsor/21/avatar.svg"></a>
+<a href="https://opencollective.com/ssh/sponsor/22/website" target="_blank"><img src="https://opencollective.com/ssh/sponsor/22/avatar.svg"></a>
+<a href="https://opencollective.com/ssh/sponsor/23/website" target="_blank"><img src="https://opencollective.com/ssh/sponsor/23/avatar.svg"></a>
+<a href="https://opencollective.com/ssh/sponsor/24/website" target="_blank"><img src="https://opencollective.com/ssh/sponsor/24/avatar.svg"></a>
+<a href="https://opencollective.com/ssh/sponsor/25/website" target="_blank"><img src="https://opencollective.com/ssh/sponsor/25/avatar.svg"></a>
+<a href="https://opencollective.com/ssh/sponsor/26/website" target="_blank"><img src="https://opencollective.com/ssh/sponsor/26/avatar.svg"></a>
+<a href="https://opencollective.com/ssh/sponsor/27/website" target="_blank"><img src="https://opencollective.com/ssh/sponsor/27/avatar.svg"></a>
+<a href="https://opencollective.com/ssh/sponsor/28/website" target="_blank"><img src="https://opencollective.com/ssh/sponsor/28/avatar.svg"></a>
+<a href="https://opencollective.com/ssh/sponsor/29/website" target="_blank"><img src="https://opencollective.com/ssh/sponsor/29/avatar.svg"></a>
+
+## License
+
+BSD

vendor/github.com/gliderlabs/ssh/agent.go

@@ -0,0 +1,83 @@
+package ssh
+
+import (
+	"io"
+	"io/ioutil"
+	"net"
+	"path"
+	"sync"
+
+	gossh "golang.org/x/crypto/ssh"
+)
+
+const (
+	agentRequestType = "auth-agent-req@openssh.com"
+	agentChannelType = "auth-agent@openssh.com"
+
+	agentTempDir    = "auth-agent"
+	agentListenFile = "listener.sock"
+)
+
+// contextKeyAgentRequest is an internal context key for storing if the
+// client requested agent forwarding
+var contextKeyAgentRequest = &contextKey{"auth-agent-req"}
+
+// SetAgentRequested sets up the session context so that AgentRequested
+// returns true.
+func SetAgentRequested(ctx Context) {
+	ctx.SetValue(contextKeyAgentRequest, true)
+}
+
+// AgentRequested returns true if the client requested agent forwarding.
+func AgentRequested(sess Session) bool {
+	return sess.Context().Value(contextKeyAgentRequest) == true
+}
+
+// NewAgentListener sets up a temporary Unix socket that can be communicated
+// to the session environment and used for forwarding connections.
+func NewAgentListener() (net.Listener, error) {
+	dir, err := ioutil.TempDir("", agentTempDir)
+	if err != nil {
+		return nil, err
+	}
+	l, err := net.Listen("unix", path.Join(dir, agentListenFile))
+	if err != nil {
+		return nil, err
+	}
+	return l, nil
+}
+
+// ForwardAgentConnections takes connections from a listener to proxy into the
+// session on the OpenSSH channel for agent connections. It blocks and services
+// connections until the listener stop accepting.
+func ForwardAgentConnections(l net.Listener, s Session) {
+	sshConn := s.Context().Value(ContextKeyConn).(gossh.Conn)
+	for {
+		conn, err := l.Accept()
+		if err != nil {
+			return
+		}
+		go func(conn net.Conn) {
+			defer conn.Close()
+			channel, reqs, err := sshConn.OpenChannel(agentChannelType, nil)
+			if err != nil {
+				return
+			}
+			defer channel.Close()
+			go gossh.DiscardRequests(reqs)
+			var wg sync.WaitGroup
+			wg.Add(2)
+			go func() {
+				io.Copy(conn, channel)
+				conn.(*net.UnixConn).CloseWrite()
+				wg.Done()
+			}()
+			go func() {
+				io.Copy(channel, conn)
+				channel.CloseWrite()
+				wg.Done()
+			}()
+			wg.Wait()
+		}(conn)
+	}
+}

vendor/github.com/gliderlabs/ssh/circle.yml

@@ -0,0 +1,26 @@
+version: 2
+jobs:
+  build-go-latest:
+    docker:
+    - image: golang:latest
+    working_directory: /go/src/github.com/gliderlabs/ssh
+    steps:
+    - checkout
+    - run: go get
+    - run: go test -v -race
+
+  build-go-1.9:
+    docker:
+    - image: golang:1.9
+    working_directory: /go/src/github.com/gliderlabs/ssh
+    steps:
+    - checkout
+    - run: go get
+    - run: go test -v -race
+
+workflows:
+  version: 2
+  build:
+    jobs:
+      - build-go-latest
+      - build-go-1.9

vendor/github.com/gliderlabs/ssh/conn.go

@@ -0,0 +1,55 @@
+package ssh
+
+import (
+	"context"
+	"net"
+	"time"
+)
+
+type serverConn struct {
+	net.Conn
+
+	idleTimeout   time.Duration
+	maxDeadline   time.Time
+	closeCanceler context.CancelFunc
+}
+
+func (c *serverConn) Write(p []byte) (n int, err error) {
+	c.updateDeadline()
+	n, err = c.Conn.Write(p)
+	if _, isNetErr := err.(net.Error); isNetErr && c.closeCanceler != nil {
+		c.closeCanceler()
+	}
+	return
+}
+
+func (c *serverConn) Read(b []byte) (n int, err error) {
+	c.updateDeadline()
+	n, err = c.Conn.Read(b)
+	if _, isNetErr := err.(net.Error); isNetErr && c.closeCanceler != nil {
+		c.closeCanceler()
+	}
+	return
+}
+
+func (c *serverConn) Close() (err error) {
+	err = c.Conn.Close()
+	if c.closeCanceler != nil {
+		c.closeCanceler()
+	}
+	return
+}
+
+func (c *serverConn) updateDeadline() {
+	switch {
+	case c.idleTimeout > 0:
+		idleDeadline := time.Now().Add(c.idleTimeout)
+		if idleDeadline.Unix() < c.maxDeadline.Unix() || c.maxDeadline.IsZero() {
+			c.Conn.SetDeadline(idleDeadline)
+			return
+		}
+		fallthrough
+	default:
+		c.Conn.SetDeadline(c.maxDeadline)
+	}
+}

vendor/github.com/gliderlabs/ssh/context.go

@@ -0,0 +1,152 @@
+package ssh
+
+import (
+	"context"
+	"encoding/hex"
+	"net"
+	"sync"
+
+	gossh "golang.org/x/crypto/ssh"
+)
+
+// contextKey is a value for use with context.WithValue. It's used as
+// a pointer so it fits in an interface{} without allocation.
+type contextKey struct {
+	name string
+}
+
+var (
+	// ContextKeyUser is a context key for use with Contexts in this package.
+	// The associated value will be of type string.
+	ContextKeyUser = &contextKey{"user"}
+
+	// ContextKeySessionID is a context key for use with Contexts in this package.
+	// The associated value will be of type string.
+	ContextKeySessionID = &contextKey{"session-id"}
+
+	// ContextKeyPermissions is a context key for use with Contexts in this package.
+	// The associated value will be of type *Permissions.
+	ContextKeyPermissions = &contextKey{"permissions"}
+
+	// ContextKeyClientVersion is a context key for use with Contexts in this package.
+	// The associated value will be of type string.
+	ContextKeyClientVersion = &contextKey{"client-version"}
+
+	// ContextKeyServerVersion is a context key for use with Contexts in this package.
+	// The associated value will be of type string.
+	ContextKeyServerVersion = &contextKey{"server-version"}
+
+	// ContextKeyLocalAddr is a context key for use with Contexts in this package.
+	// The associated value will be of type net.Addr.
+	ContextKeyLocalAddr = &contextKey{"local-addr"}
+
+	// ContextKeyRemoteAddr is a context key for use with Contexts in this package.
+	// The associated value will be of type net.Addr.
+	ContextKeyRemoteAddr = &contextKey{"remote-addr"}
+
+	// ContextKeyServer is a context key for use with Contexts in this package.
+	// The associated value will be of type *Server.
+	ContextKeyServer = &contextKey{"ssh-server"}
+
+	// ContextKeyConn is a context key for use with Contexts in this package.
+	// The associated value will be of type gossh.ServerConn.
+	ContextKeyConn = &contextKey{"ssh-conn"}
+
+	// ContextKeyPublicKey is a context key for use with Contexts in this package.
+	// The associated value will be of type PublicKey.
+	ContextKeyPublicKey = &contextKey{"public-key"}
+)
+
+// Context is a package specific context interface. It exposes connection
+// metadata and allows new values to be easily written to it. It's used in
+// authentication handlers and callbacks, and its underlying context.Context is
+// exposed on Session in the session Handler. A connection-scoped lock is also
+// embedded in the context to make it easier to limit operations per-connection.
+type Context interface {
+	context.Context
+	sync.Locker
+
+	// User returns the username used when establishing the SSH connection.
+	User() string
+
+	// SessionID returns the session hash.
+	SessionID() string
+
+	// ClientVersion returns the version reported by the client.
+	ClientVersion() string
+
+	// ServerVersion returns the version reported by the server.
+	ServerVersion() string
+
+	// RemoteAddr returns the remote address for this connection.
+	RemoteAddr() net.Addr
+
+	// LocalAddr returns the local address for this connection.
+	LocalAddr() net.Addr
+
+	// Permissions returns the Permissions object used for this connection.
+	Permissions() *Permissions
+
+	// SetValue allows you to easily write new values into the underlying context.
+	SetValue(key, value interface{})
+}
+
+type sshContext struct {
+	context.Context
+	*sync.Mutex
+}
+
+func newContext(srv *Server) (*sshContext, context.CancelFunc) {
+	innerCtx, cancel := context.WithCancel(context.Background())
+	ctx := &sshContext{innerCtx, &sync.Mutex{}}
+	ctx.SetValue(ContextKeyServer, srv)
+	perms := &Permissions{&gossh.Permissions{}}
+	ctx.SetValue(ContextKeyPermissions, perms)
+	return ctx, cancel
+}
+
+// this is separate from newContext because we will get ConnMetadata
+// at different points so it needs to be applied separately
+func applyConnMetadata(ctx Context, conn gossh.ConnMetadata) {
+	if ctx.Value(ContextKeySessionID) != nil {
+		return
+	}
+	ctx.SetValue(ContextKeySessionID, hex.EncodeToString(conn.SessionID()))
+	ctx.SetValue(ContextKeyClientVersion, string(conn.ClientVersion()))
+	ctx.SetValue(ContextKeyServerVersion, string(conn.ServerVersion()))
+	ctx.SetValue(ContextKeyUser, conn.User())
+	ctx.SetValue(ContextKeyLocalAddr, conn.LocalAddr())
+	ctx.SetValue(ContextKeyRemoteAddr, conn.RemoteAddr())
+}
+
+func (ctx *sshContext) SetValue(key, value interface{}) {
+	ctx.Context = context.WithValue(ctx.Context, key, value)
+}
+
+func (ctx *sshContext) User() string {
+	return ctx.Value(ContextKeyUser).(string)
+}
+
+func (ctx *sshContext) SessionID() string {
+	return ctx.Value(ContextKeySessionID).(string)
+}
+
+func (ctx *sshContext) ClientVersion() string {
+	return ctx.Value(ContextKeyClientVersion).(string)
+}
+
+func (ctx *sshContext) ServerVersion() string {
+	return ctx.Value(ContextKeyServerVersion).(string)
+}
+
+func (ctx *sshContext) RemoteAddr() net.Addr {
+	return ctx.Value(ContextKeyRemoteAddr).(net.Addr)
+}
+
+func (ctx *sshContext) LocalAddr() net.Addr {
+	return ctx.Value(ContextKeyLocalAddr).(net.Addr)
+}
+
+func (ctx *sshContext) Permissions() *Permissions {
+	return ctx.Value(ContextKeyPermissions).(*Permissions)
+}

vendor/github.com/gliderlabs/ssh/doc.go

@@ -0,0 +1,45 @@
+/*
+Package ssh wraps the crypto/ssh package with a higher-level API for building
+SSH servers. The goal of the API was to make it as simple as using net/http, so
+the API is very similar.
+
+You should be able to build any SSH server using only this package, which wraps
+relevant types and some functions from crypto/ssh. However, you still need to
+use crypto/ssh for building SSH clients.
+
+ListenAndServe starts an SSH server with a given address, handler, and options. The
+handler is usually nil, which means to use DefaultHandler. Handle sets DefaultHandler:
+
+  ssh.Handle(func(s ssh.Session) {
+      io.WriteString(s, "Hello world\n")
+  })
+
+  log.Fatal(ssh.ListenAndServe(":2222", nil))
+
+If you don't specify a host key, it will generate one every time. This is convenient
+except you'll have to deal with clients being confused that the host key is different.
+It's a better idea to generate or point to an existing key on your system:
+
+  log.Fatal(ssh.ListenAndServe(":2222", nil, ssh.HostKeyFile("/Users/progrium/.ssh/id_rsa")))
+
+Although all options have functional option helpers, another way to control the
+server's behavior is by creating a custom Server:
+
+  s := &ssh.Server{
+      Addr:             ":2222",
+      Handler:          sessionHandler,
+      PublicKeyHandler: authHandler,
+  }
+  s.AddHostKey(hostKeySigner)
+
+  log.Fatal(s.ListenAndServe())
+
+This package automatically handles basic SSH requests like setting environment
+variables, requesting PTY, and changing window size. These requests are
+processed, responded to, and any relevant state is updated. This state is then
+exposed to you via the Session interface.
+
+The one big feature missing from the Session abstraction is signals. This was
+started, but not completed. Pull Requests welcome!
+*/
+package ssh

vendor/github.com/gliderlabs/ssh/options.go

@@ -0,0 +1,77 @@
+package ssh
+
+import (
+	"io/ioutil"
+
+	gossh "golang.org/x/crypto/ssh"
+)
+
+// PasswordAuth returns a functional option that sets PasswordHandler on the server.
+func PasswordAuth(fn PasswordHandler) Option {
+	return func(srv *Server) error {
+		srv.PasswordHandler = fn
+		return nil
+	}
+}
+
+// PublicKeyAuth returns a functional option that sets PublicKeyHandler on the server.
+func PublicKeyAuth(fn PublicKeyHandler) Option {
+	return func(srv *Server) error {
+		srv.PublicKeyHandler = fn
+		return nil
+	}
+}
+
+// HostKeyFile returns a functional option that adds HostSigners to the server
+// from a PEM file at filepath.
+func HostKeyFile(filepath string) Option {
+	return func(srv *Server) error {
+		pemBytes, err := ioutil.ReadFile(filepath)
+		if err != nil {
+			return err
+		}
+
+		signer, err := gossh.ParsePrivateKey(pemBytes)
+		if err != nil {
+			return err
+		}
+
+		srv.AddHostKey(signer)
+
+		return nil
+	}
+}
+
+// HostKeyPEM returns a functional option that adds HostSigners to the server
+// from a PEM file as bytes.
+func HostKeyPEM(bytes []byte) Option {
+	return func(srv *Server) error {
+		signer, err := gossh.ParsePrivateKey(bytes)
+		if err != nil {
+			return err
+		}
+
+		srv.AddHostKey(signer)
+
+		return nil
+	}
+}
+
+// NoPty returns a functional option that sets PtyCallback to return false,
+// denying PTY requests.
+func NoPty() Option {
+	return func(srv *Server) error {
+		srv.PtyCallback = func(ctx Context, pty Pty) bool {
+			return false
+		}
+		return nil
+	}
+}
+
+// WrapConn returns a functional option that sets ConnCallback on the server.
+func WrapConn(fn ConnCallback) Option {
+	return func(srv *Server) error {
+		srv.ConnCallback = fn
+		return nil
+	}
+}

vendor/github.com/gliderlabs/ssh/server.go

@@ -0,0 +1,394 @@
+package ssh
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net"
+	"sync"
+	"time"
+
+	gossh "golang.org/x/crypto/ssh"
+)
+
+// ErrServerClosed is returned by the Server's Serve, ListenAndServe,
+// and ListenAndServeTLS methods after a call to Shutdown or Close.
+var ErrServerClosed = errors.New("ssh: Server closed")
+
+type RequestHandler func(ctx Context, srv *Server, req *gossh.Request) (ok bool, payload []byte)
+
+var DefaultRequestHandlers = map[string]RequestHandler{}
+
+type ChannelHandler func(srv *Server, conn *gossh.ServerConn, newChan gossh.NewChannel, ctx Context)
+
+var DefaultChannelHandlers = map[string]ChannelHandler{
+	"session": DefaultSessionHandler,
+}
+
+// Server defines parameters for running an SSH server. The zero value for
+// Server is a valid configuration. When both PasswordHandler and
+// PublicKeyHandler are nil, no client authentication is performed.
+type Server struct {
+	Addr        string   // TCP address to listen on, ":22" if empty
+	Handler     Handler  // handler to invoke, ssh.DefaultHandler if nil
+	HostSigners []Signer // private keys for the host key, must have at least one
+	Version     string   // server version to be sent before the initial handshake
+
+	KeyboardInteractiveHandler    KeyboardInteractiveHandler    // keyboard-interactive authentication handler
+	PasswordHandler               PasswordHandler               // password authentication handler
+	PublicKeyHandler              PublicKeyHandler              // public key authentication handler
+	PtyCallback                   PtyCallback                   // callback for allowing PTY sessions, allows all if nil
+	ConnCallback                  ConnCallback                  // optional callback for wrapping net.Conn before handling
+	LocalPortForwardingCallback   LocalPortForwardingCallback   // callback for allowing local port forwarding, denies all if nil
+	ReversePortForwardingCallback ReversePortForwardingCallback // callback for allowing reverse port forwarding, denies all if nil
+	ServerConfigCallback          ServerConfigCallback          // callback for configuring detailed SSH options
+	SessionRequestCallback        SessionRequestCallback        // callback for allowing or denying SSH sessions
+
+	IdleTimeout time.Duration // connection timeout when no activity, none if empty
+	MaxTimeout  time.Duration // absolute connection timeout, none if empty
+
+	// ChannelHandlers allow overriding the built-in session handlers or provide
+	// extensions to the protocol, such as tcpip forwarding. By default only the
+	// "session" handler is enabled.
+	ChannelHandlers map[string]ChannelHandler
+
+	// RequestHandlers allow overriding the server-level request handlers or
+	// provide extensions to the protocol, such as tcpip forwarding. By default
+	// no handlers are enabled.
+	RequestHandlers map[string]RequestHandler
+
+	listenerWg sync.WaitGroup
+	mu         sync.Mutex
+	listeners  map[net.Listener]struct{}
+	conns      map[*gossh.ServerConn]struct{}
+	connWg     sync.WaitGroup
+	doneChan   chan struct{}
+}
+
+func (srv *Server) ensureHostSigner() error {
+	if len(srv.HostSigners) == 0 {
+		signer, err := generateSigner()
+		if err != nil {
+			return err
+		}
+		srv.HostSigners = append(srv.HostSigners, signer)
+	}
+	return nil
+}
+
+func (srv *Server) ensureHandlers() {
+	srv.mu.Lock()
+	defer srv.mu.Unlock()
+	if srv.RequestHandlers == nil {
+		srv.RequestHandlers = map[string]RequestHandler{}
+		for k, v := range DefaultRequestHandlers {
+			srv.RequestHandlers[k] = v
+		}
+	}
+	if srv.ChannelHandlers == nil {
+		srv.ChannelHandlers = map[string]ChannelHandler{}
+		for k, v := range DefaultChannelHandlers {
+			srv.ChannelHandlers[k] = v
+		}
+	}
+}
+
+func (srv *Server) config(ctx Context) *gossh.ServerConfig {
+	var config *gossh.ServerConfig
+	if srv.ServerConfigCallback == nil {
+		config = &gossh.ServerConfig{}
+	} else {
+		config = srv.ServerConfigCallback(ctx)
+	}
+	for _, signer := range srv.HostSigners {
+		config.AddHostKey(signer)
+	}
+	if srv.PasswordHandler == nil && srv.PublicKeyHandler == nil {
+		config.NoClientAuth = true
+	}
+	if srv.Version != "" {
+		config.ServerVersion = "SSH-2.0-" + srv.Version
+	}
+	if srv.PasswordHandler != nil {
+		config.PasswordCallback = func(conn gossh.ConnMetadata, password []byte) (*gossh.Permissions, error) {
+			applyConnMetadata(ctx, conn)
+			if ok := srv.PasswordHandler(ctx, string(password)); !ok {
+				return ctx.Permissions().Permissions, fmt.Errorf("permission denied")
+			}
+			return ctx.Permissions().Permissions, nil
+		}
+	}
+	if srv.PublicKeyHandler != nil {
+		config.PublicKeyCallback = func(conn gossh.ConnMetadata, key gossh.PublicKey) (*gossh.Permissions, error) {
+			applyConnMetadata(ctx, conn)
+			if ok := srv.PublicKeyHandler(ctx, key); !ok {
+				return ctx.Permissions().Permissions, fmt.Errorf("permission denied")
+			}
+			ctx.SetValue(ContextKeyPublicKey, key)
+			return ctx.Permissions().Permissions, nil
+		}
+	}
+	if srv.KeyboardInteractiveHandler != nil {
+		config.KeyboardInteractiveCallback = func(conn gossh.ConnMetadata, challenger gossh.KeyboardInteractiveChallenge) (*gossh.Permissions, error) {
+			if ok := srv.KeyboardInteractiveHandler(ctx, challenger); !ok {
+				return ctx.Permissions().Permissions, fmt.Errorf("permission denied")
+			}
+			return ctx.Permissions().Permissions, nil
+		}
+	}
+	return config
+}
+
+// Handle sets the Handler for the server.
+func (srv *Server) Handle(fn Handler) {
+	srv.Handler = fn
+}
+
+// Close immediately closes all active listeners and all active
+// connections.
+//
+// Close returns any error returned from closing the Server's
+// underlying Listener(s).
+func (srv *Server) Close() error {
+	srv.mu.Lock()
+	defer srv.mu.Unlock()
+	srv.closeDoneChanLocked()
+	err := srv.closeListenersLocked()
+	for c := range srv.conns {
+		c.Close()
+		delete(srv.conns, c)
+	}
+	return err
+}
+
+// Shutdown gracefully shuts down the server without interrupting any
+// active connections. Shutdown works by first closing all open
+// listeners, and then waiting indefinitely for connections to close.
+// If the provided context expires before the shutdown is complete,
+// then the context's error is returned.
+func (srv *Server) Shutdown(ctx context.Context) error {
+	srv.mu.Lock()
+	lnerr := srv.closeListenersLocked()
+	srv.closeDoneChanLocked()
+	srv.mu.Unlock()
+
+	finished := make(chan struct{}, 1)
+	go func() {
+		srv.listenerWg.Wait()
+		srv.connWg.Wait()
+		finished <- struct{}{}
+	}()
+
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	case <-finished:
+		return lnerr
+	}
+}
+
+// Serve accepts incoming connections on the Listener l, creating a new
+// connection goroutine for each. The connection goroutines read requests and then
+// calls srv.Handler to handle sessions.
+//
+// Serve always returns a non-nil error.
+func (srv *Server) Serve(l net.Listener) error {
+	srv.ensureHandlers()
+	defer l.Close()
+	if err := srv.ensureHostSigner(); err != nil {
+		return err
+	}
+	if srv.Handler == nil {
+		srv.Handler = DefaultHandler
+	}
+	var tempDelay time.Duration
+
+	srv.trackListener(l, true)
+	defer srv.trackListener(l, false)
+	for {
+		conn, e := l.Accept()
+		if e != nil {
+			select {
+			case <-srv.getDoneChan():
+				return ErrServerClosed
+			default:
+			}
+			if ne, ok := e.(net.Error); ok && ne.Temporary() {
+				if tempDelay == 0 {
+					tempDelay = 5 * time.Millisecond
+				} else {
+					tempDelay *= 2
+				}
+				if max := 1 * time.Second; tempDelay > max {
+					tempDelay = max
+				}
+				time.Sleep(tempDelay)
+				continue
+			}
+			return e
+		}
+		go srv.handleConn(conn)
+	}
+}
+
+func (srv *Server) handleConn(newConn net.Conn) {
+	if srv.ConnCallback != nil {
+		cbConn := srv.ConnCallback(newConn)
+		if cbConn == nil {
+			newConn.Close()
+			return
+		}
+		newConn = cbConn
+	}
+	ctx, cancel := newContext(srv)
+	conn := &serverConn{
+		Conn:          newConn,
+		idleTimeout:   srv.IdleTimeout,
+		closeCanceler: cancel,
+	}
+	if srv.MaxTimeout > 0 {
+		conn.maxDeadline = time.Now().Add(srv.MaxTimeout)
+	}
+	defer conn.Close()
+	sshConn, chans, reqs, err := gossh.NewServerConn(conn, srv.config(ctx))
+	if err != nil {
+		// TODO: trigger event callback
+		return
+	}
+
+	srv.trackConn(sshConn, true)
+	defer srv.trackConn(sshConn, false)
+
+	ctx.SetValue(ContextKeyConn, sshConn)
+	applyConnMetadata(ctx, sshConn)
+	//go gossh.DiscardRequests(reqs)
+	go srv.handleRequests(ctx, reqs)
+	for ch := range chans {
+		handler := srv.ChannelHandlers[ch.ChannelType()]
+		if handler == nil {
+			handler = srv.ChannelHandlers["default"]
+		}
+		if handler == nil {
+			ch.Reject(gossh.UnknownChannelType, "unsupported channel type")
+			continue
+		}
+		go handler(srv, sshConn, ch, ctx)
+	}
+}
+
+func (srv *Server) handleRequests(ctx Context, in <-chan *gossh.Request) {
+	for req := range in {
+		handler := srv.RequestHandlers[req.Type]
+		if handler == nil {
+			handler = srv.RequestHandlers["default"]
+		}
+		if handler == nil {
+			req.Reply(false, nil)
+			continue
+		}
+		/*reqCtx, cancel := context.WithCancel(ctx)
+		defer cancel() */
+		ret, payload := handler(ctx, srv, req)
+		req.Reply(ret, payload)
+	}
+}
+
+// ListenAndServe listens on the TCP network address srv.Addr and then calls
+// Serve to handle incoming connections. If srv.Addr is blank, ":22" is used.
+// ListenAndServe always returns a non-nil error.
+func (srv *Server) ListenAndServe() error {
+	addr := srv.Addr
+	if addr == "" {
+		addr = ":22"
+	}
+	ln, err := net.Listen("tcp", addr)
+	if err != nil {
+		return err
+	}
+	return srv.Serve(ln)
+}
+
+// AddHostKey adds a private key as a host key. If an existing host key exists
+// with the same algorithm, it is overwritten. Each server config must have at
+// least one host key.
+func (srv *Server) AddHostKey(key Signer) {
+	// these are later added via AddHostKey on ServerConfig, which performs the
+	// check for one of every algorithm.
+	srv.HostSigners = append(srv.HostSigners, key)
+}
+
+// SetOption runs a functional option against the server.
+func (srv *Server) SetOption(option Option) error {
+	return option(srv)
+}
+
+func (srv *Server) getDoneChan() <-chan struct{} {
+	srv.mu.Lock()
+	defer srv.mu.Unlock()
+	return srv.getDoneChanLocked()
+}
+
+func (srv *Server) getDoneChanLocked() chan struct{} {
+	if srv.doneChan == nil {
+		srv.doneChan = make(chan struct{})
+	}
+	return srv.doneChan
+}
+
+func (srv *Server) closeDoneChanLocked() {
+	ch := srv.getDoneChanLocked()
+	select {
+	case <-ch:
+		// Already closed. Don't close again.
+	default:
+		// Safe to close here. We're the only closer, guarded
+		// by srv.mu.
+		close(ch)
+	}
+}
+
+func (srv *Server) closeListenersLocked() error {
+	var err error
+	for ln := range srv.listeners {
+		if cerr := ln.Close(); cerr != nil && err == nil {
+			err = cerr
+		}
+		delete(srv.listeners, ln)
+	}
+	return err
+}
+
+func (srv *Server) trackListener(ln net.Listener, add bool) {
+	srv.mu.Lock()
+	defer srv.mu.Unlock()
+	if srv.listeners == nil {
+		srv.listeners = make(map[net.Listener]struct{})
+	}
+	if add {
+		// If the *Server is being reused after a previous
+		// Close or Shutdown, reset its doneChan:
+		if len(srv.listeners) == 0 && len(srv.conns) == 0 {
+			srv.doneChan = nil
+		}
+		srv.listeners[ln] = struct{}{}
+		srv.listenerWg.Add(1)
+	} else {
+		delete(srv.listeners, ln)
+		srv.listenerWg.Done()
+	}
+}
+
+func (srv *Server) trackConn(c *gossh.ServerConn, add bool) {
+	srv.mu.Lock()
+	defer srv.mu.Unlock()
+	if srv.conns == nil {
+		srv.conns = make(map[*gossh.ServerConn]struct{})
+	}
+	if add {
+		srv.conns[c] = struct{}{}
+		srv.connWg.Add(1)
+	} else {
+		delete(srv.conns, c)
+		srv.connWg.Done()
+	}
+}

vendor/github.com/gliderlabs/ssh/session.go

@@ -0,0 +1,308 @@
+package ssh
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"net"
+	"sync"
+
+	"github.com/anmitsu/go-shlex"
+	gossh "golang.org/x/crypto/ssh"
+)
+
+// Session provides access to information about an SSH session and methods
+// to read and write to the SSH channel with an embedded Channel interface from
+// cypto/ssh.
+//
+// When Command() returns an empty slice, the user requested a shell. Otherwise
+// the user is performing an exec with those command arguments.
+//
+// TODO: Signals
+type Session interface {
+	gossh.Channel
+
+	// User returns the username used when establishing the SSH connection.
+	User() string
+
+	// RemoteAddr returns the net.Addr of the client side of the connection.
+	RemoteAddr() net.Addr
+
+	// LocalAddr returns the net.Addr of the server side of the connection.
+	LocalAddr() net.Addr
+
+	// Environ returns a copy of strings representing the environment set by the
+	// user for this session, in the form "key=value".
+	Environ() []string
+
+	// Exit sends an exit status and then closes the session.
+	Exit(code int) error
+
+	// Command returns a shell parsed slice of arguments that were provided by the
+	// user. Shell parsing splits the command string according to POSIX shell rules,
+	// which considers quoting not just whitespace.
+	Command() []string
+
+	// RawCommand returns the exact command that was provided by the user.
+	RawCommand() string
+
+	// PublicKey returns the PublicKey used to authenticate. If a public key was not
+	// used it will return nil.
+	PublicKey() PublicKey
+
+	// Context returns the connection's context. The returned context is always
+	// non-nil and holds the same data as the Context passed into auth
+	// handlers and callbacks.
+	//
+	// The context is canceled when the client's connection closes or I/O
+	// operation fails.
+	Context() context.Context
+
+	// Permissions returns a copy of the Permissions object that was available for
+	// setup in the auth handlers via the Context.
+	Permissions() Permissions
+
+	// Pty returns PTY information, a channel of window size changes, and a boolean
+	// of whether or not a PTY was accepted for this session.
+	Pty() (Pty, <-chan Window, bool)
+
+	// Signals registers a channel to receive signals sent from the client. The
+	// channel must handle signal sends or it will block the SSH request loop.
+	// Registering nil will unregister the channel from signal sends. During the
+	// time no channel is registered signals are buffered up to a reasonable amount.
+	// 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)
+}
+
+// maxSigBufSize is how many signals will be buffered
+// when there is no signal channel specified
+const maxSigBufSize = 128
+
+func DefaultSessionHandler(srv *Server, conn *gossh.ServerConn, newChan gossh.NewChannel, ctx Context) {
+	ch, reqs, err := newChan.Accept()
+	if err != nil {
+		// TODO: trigger event callback
+		return
+	}
+	sess := &session{
+		Channel:   ch,
+		conn:      conn,
+		handler:   srv.Handler,
+		ptyCb:     srv.PtyCallback,
+		sessReqCb: srv.SessionRequestCallback,
+		ctx:       ctx,
+	}
+	sess.handleRequests(reqs)
+}
+
+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
+	sessReqCb SessionRequestCallback
+	rawCmd    string
+	ctx       Context
+	sigCh     chan<- Signal
+	sigBuf    []Signal
+}
+
+func (sess *session) Write(p []byte) (n int, err error) {
+	if sess.pty != nil {
+		m := len(p)
+		// normalize \n to \r\n when pty is accepted.
+		// this is a hardcoded shortcut since we don't support terminal modes.
+		p = bytes.Replace(p, []byte{'\n'}, []byte{'\r', '\n'}, -1)
+		p = bytes.Replace(p, []byte{'\r', '\r', '\n'}, []byte{'\r', '\n'}, -1)
+		n, err = sess.Channel.Write(p)
+		if n > m {
+			n = m
+		}
+		return
+	}
+	return sess.Channel.Write(p)
+}
+
+func (sess *session) PublicKey() PublicKey {
+	sessionkey := sess.ctx.Value(ContextKeyPublicKey)
+	if sessionkey == nil {
+		return nil
+	}
+	return sessionkey.(PublicKey)
+}
+
+func (sess *session) Permissions() Permissions {
+	// use context permissions because its properly
+	// wrapped and easier to dereference
+	perms := sess.ctx.Value(ContextKeyPermissions).(*Permissions)
+	return *perms
+}
+
+func (sess *session) Context() context.Context {
+	return sess.ctx
+}
+
+func (sess *session) Exit(code int) error {
+	sess.Lock()
+	defer sess.Unlock()
+	if sess.exited {
+		return errors.New("Session.Exit called multiple times")
+	}
+	sess.exited = true
+
+	status := struct{ Status uint32 }{uint32(code)}
+	_, err := sess.SendRequest("exit-status", false, gossh.Marshal(&status))
+	if err != nil {
+		return err
+	}
+	return sess.Close()
+}
+
+func (sess *session) User() string {
+	return sess.conn.User()
+}
+
+func (sess *session) RemoteAddr() net.Addr {
+	return sess.conn.RemoteAddr()
+}
+
+func (sess *session) LocalAddr() net.Addr {
+	return sess.conn.LocalAddr()
+}
+
+func (sess *session) Environ() []string {
+	return append([]string(nil), sess.env...)
+}
+
+func (sess *session) RawCommand() string {
+	return sess.rawCmd
+}
+
+func (sess *session) Command() []string {
+	cmd, _ := shlex.Split(sess.rawCmd, true)
+	return append([]string(nil), cmd...)
+}
+
+func (sess *session) Pty() (Pty, <-chan Window, bool) {
+	if sess.pty != nil {
+		return *sess.pty, sess.winch, true
+	}
+	return Pty{}, sess.winch, false
+}
+
+func (sess *session) Signals(c chan<- Signal) {
+	sess.Lock()
+	defer sess.Unlock()
+	sess.sigCh = c
+	if len(sess.sigBuf) > 0 {
+		go func() {
+			for _, sig := range sess.sigBuf {
+				sess.sigCh <- sig
+			}
+		}()
+	}
+}
+
+func (sess *session) handleRequests(reqs <-chan *gossh.Request) {
+	for req := range reqs {
+		switch req.Type {
+		case "shell", "exec":
+			if sess.handled {
+				req.Reply(false, nil)
+				continue
+			}
+
+			var payload = struct{ Value string }{}
+			gossh.Unmarshal(req.Payload, &payload)
+			sess.rawCmd = payload.Value
+
+			// If there's a session policy callback, we need to confirm before
+			// accepting the session.
+			if sess.sessReqCb != nil && !sess.sessReqCb(sess, req.Type) {
+				sess.rawCmd = ""
+				req.Reply(false, nil)
+				continue
+			}
+
+			sess.handled = true
+			req.Reply(true, nil)
+
+			go func() {
+				sess.handler(sess)
+				sess.Exit(0)
+			}()
+		case "env":
+			if sess.handled {
+				req.Reply(false, nil)
+				continue
+			}
+			var kv struct{ Key, Value string }
+			gossh.Unmarshal(req.Payload, &kv)
+			sess.env = append(sess.env, fmt.Sprintf("%s=%s", kv.Key, kv.Value))
+			req.Reply(true, nil)
+		case "signal":
+			var payload struct{ Signal string }
+			gossh.Unmarshal(req.Payload, &payload)
+			sess.Lock()
+			if sess.sigCh != nil {
+				sess.sigCh <- Signal(payload.Signal)
+			} else {
+				if len(sess.sigBuf) < maxSigBufSize {
+					sess.sigBuf = append(sess.sigBuf, Signal(payload.Signal))
+				}
+			}
+			sess.Unlock()
+		case "pty-req":
+			if sess.handled || sess.pty != nil {
+				req.Reply(false, nil)
+				continue
+			}
+			ptyReq, ok := parsePtyRequest(req.Payload)
+			if !ok {
+				req.Reply(false, nil)
+				continue
+			}
+			if sess.ptyCb != nil {
+				ok := sess.ptyCb(sess.ctx, ptyReq)
+				if !ok {
+					req.Reply(false, nil)
+					continue
+				}
+			}
+			sess.pty = &ptyReq
+			sess.winch = make(chan Window, 1)
+			sess.winch <- ptyReq.Window
+			defer func() {
+				// when reqs is closed
+				close(sess.winch)
+			}()
+			req.Reply(ok, nil)
+		case "window-change":
+			if sess.pty == nil {
+				req.Reply(false, nil)
+				continue
+			}
+			win, ok := parseWinchRequest(req.Payload)
+			if ok {
+				sess.pty.Window = win
+				sess.winch <- win
+			}
+			req.Reply(ok, nil)
+		case agentRequestType:
+			// TODO: option/callback to allow agent forwarding
+			SetAgentRequested(sess.ctx)
+			req.Reply(true, nil)
+		default:
+			// TODO: debug log
+			req.Reply(false, nil)
+		}
+	}
+}

vendor/github.com/gliderlabs/ssh/ssh.go

@@ -0,0 +1,123 @@
+package ssh
+
+import (
+	"crypto/subtle"
+	"net"
+
+	gossh "golang.org/x/crypto/ssh"
+)
+
+type Signal string
+
+// POSIX signals as listed in RFC 4254 Section 6.10.
+const (
+	SIGABRT Signal = "ABRT"
+	SIGALRM Signal = "ALRM"
+	SIGFPE  Signal = "FPE"
+	SIGHUP  Signal = "HUP"
+	SIGILL  Signal = "ILL"
+	SIGINT  Signal = "INT"
+	SIGKILL Signal = "KILL"
+	SIGPIPE Signal = "PIPE"
+	SIGQUIT Signal = "QUIT"
+	SIGSEGV Signal = "SEGV"
+	SIGTERM Signal = "TERM"
+	SIGUSR1 Signal = "USR1"
+	SIGUSR2 Signal = "USR2"
+)
+
+// DefaultHandler is the default Handler used by Serve.
+var DefaultHandler Handler
+
+// Option is a functional option handler for Server.
+type Option func(*Server) error
+
+// Handler is a callback for handling established SSH sessions.
+type Handler func(Session)
+
+// PublicKeyHandler is a callback for performing public key authentication.
+type PublicKeyHandler func(ctx Context, key PublicKey) bool
+
+// PasswordHandler is a callback for performing password authentication.
+type PasswordHandler func(ctx Context, password string) bool
+
+// KeyboardInteractiveHandler is a callback for performing keyboard-interactive authentication.
+type KeyboardInteractiveHandler func(ctx Context, challenger gossh.KeyboardInteractiveChallenge) bool
+
+// PtyCallback is a hook for allowing PTY sessions.
+type PtyCallback func(ctx Context, pty Pty) bool
+
+// SessionRequestCallback is a callback for allowing or denying SSH sessions.
+type SessionRequestCallback func(sess Session, requestType string) bool
+
+// ConnCallback is a hook for new connections before handling.
+// It allows wrapping for timeouts and limiting by returning
+// the net.Conn that will be used as the underlying connection.
+type ConnCallback func(conn net.Conn) net.Conn
+
+// LocalPortForwardingCallback is a hook for allowing port forwarding
+type LocalPortForwardingCallback func(ctx Context, destinationHost string, destinationPort uint32) bool
+
+// ReversePortForwardingCallback is a hook for allowing reverse port forwarding
+type ReversePortForwardingCallback func(ctx Context, bindHost string, bindPort uint32) bool
+
+// ServerConfigCallback is a hook for creating custom default server configs
+type ServerConfigCallback func(ctx Context) *gossh.ServerConfig
+
+// Window represents the size of a PTY window.
+type Window struct {
+	Width  int
+	Height int
+}
+
+// Pty represents a PTY request and configuration.
+type Pty struct {
+	Term   string
+	Window Window
+	// HELP WANTED: terminal modes!
+}
+
+// Serve accepts incoming SSH connections on the listener l, creating a new
+// connection goroutine for each. The connection goroutines read requests and
+// then calls handler to handle sessions. Handler is typically nil, in which
+// case the DefaultHandler is used.
+func Serve(l net.Listener, handler Handler, options ...Option) error {
+	srv := &Server{Handler: handler}
+	for _, option := range options {
+		if err := srv.SetOption(option); err != nil {
+			return err
+		}
+	}
+	return srv.Serve(l)
+}
+
+// ListenAndServe listens on the TCP network address addr and then calls Serve
+// with handler to handle sessions on incoming connections. Handler is typically
+// nil, in which case the DefaultHandler is used.
+func ListenAndServe(addr string, handler Handler, options ...Option) error {
+	srv := &Server{Addr: addr, Handler: handler}
+	for _, option := range options {
+		if err := srv.SetOption(option); err != nil {
+			return err
+		}
+	}
+	return srv.ListenAndServe()
+}
+
+// Handle registers the handler as the DefaultHandler.
+func Handle(handler Handler) {
+	DefaultHandler = handler
+}
+
+// KeysEqual is constant time compare of the keys to avoid timing attacks.
+func KeysEqual(ak, bk PublicKey) bool {
+
+	//avoid panic if one of the keys is nil, return false instead
+	if ak == nil || bk == nil {
+		return false
+	}
+
+	a := ak.Marshal()
+	b := bk.Marshal()
+	return (len(a) == len(b) && subtle.ConstantTimeCompare(a, b) == 1)
+}

vendor/github.com/gliderlabs/ssh/tcpip.go

@@ -0,0 +1,193 @@
+package ssh
+
+import (
+	"io"
+	"log"
+	"net"
+	"strconv"
+	"sync"
+
+	gossh "golang.org/x/crypto/ssh"
+)
+
+const (
+	forwardedTCPChannelType = "forwarded-tcpip"
+)
+
+// direct-tcpip data struct as specified in RFC4254, Section 7.2
+type localForwardChannelData struct {
+	DestAddr string
+	DestPort uint32
+
+	OriginAddr string
+	OriginPort uint32
+}
+
+// DirectTCPIPHandler can be enabled by adding it to the server's
+// ChannelHandlers under direct-tcpip.
+func DirectTCPIPHandler(srv *Server, conn *gossh.ServerConn, newChan gossh.NewChannel, ctx Context) {
+	d := localForwardChannelData{}
+	if err := gossh.Unmarshal(newChan.ExtraData(), &d); err != nil {
+		newChan.Reject(gossh.ConnectionFailed, "error parsing forward data: "+err.Error())
+		return
+	}
+
+	if srv.LocalPortForwardingCallback == nil || !srv.LocalPortForwardingCallback(ctx, d.DestAddr, d.DestPort) {
+		newChan.Reject(gossh.Prohibited, "port forwarding is disabled")
+		return
+	}
+
+	dest := net.JoinHostPort(d.DestAddr, strconv.FormatInt(int64(d.DestPort), 10))
+
+	var dialer net.Dialer
+	dconn, err := dialer.DialContext(ctx, "tcp", dest)
+	if err != nil {
+		newChan.Reject(gossh.ConnectionFailed, err.Error())
+		return
+	}
+
+	ch, reqs, err := newChan.Accept()
+	if err != nil {
+		dconn.Close()
+		return
+	}
+	go gossh.DiscardRequests(reqs)
+
+	go func() {
+		defer ch.Close()
+		defer dconn.Close()
+		io.Copy(ch, dconn)
+	}()
+	go func() {
+		defer ch.Close()
+		defer dconn.Close()
+		io.Copy(dconn, ch)
+	}()
+}
+
+type remoteForwardRequest struct {
+	BindAddr string
+	BindPort uint32
+}
+
+type remoteForwardSuccess struct {
+	BindPort uint32
+}
+
+type remoteForwardCancelRequest struct {
+	BindAddr string
+	BindPort uint32
+}
+
+type remoteForwardChannelData struct {
+	DestAddr   string
+	DestPort   uint32
+	OriginAddr string
+	OriginPort uint32
+}
+
+// ForwardedTCPHandler can be enabled by creating a ForwardedTCPHandler and
+// adding the HandleSSHRequest callback to the server's RequestHandlers under
+// tcpip-forward and cancel-tcpip-forward.
+type ForwardedTCPHandler struct {
+	forwards map[string]net.Listener
+	sync.Mutex
+}
+
+func (h *ForwardedTCPHandler) HandleSSHRequest(ctx Context, srv *Server, req *gossh.Request) (bool, []byte) {
+	h.Lock()
+	if h.forwards == nil {
+		h.forwards = make(map[string]net.Listener)
+	}
+	h.Unlock()
+	conn := ctx.Value(ContextKeyConn).(*gossh.ServerConn)
+	switch req.Type {
+	case "tcpip-forward":
+		var reqPayload remoteForwardRequest
+		if err := gossh.Unmarshal(req.Payload, &reqPayload); err != nil {
+			// TODO: log parse failure
+			return false, []byte{}
+		}
+		if srv.ReversePortForwardingCallback == nil || !srv.ReversePortForwardingCallback(ctx, reqPayload.BindAddr, reqPayload.BindPort) {
+			return false, []byte("port forwarding is disabled")
+		}
+		addr := net.JoinHostPort(reqPayload.BindAddr, strconv.Itoa(int(reqPayload.BindPort)))
+		ln, err := net.Listen("tcp", addr)
+		if err != nil {
+			// TODO: log listen failure
+			return false, []byte{}
+		}
+		_, destPortStr, _ := net.SplitHostPort(ln.Addr().String())
+		destPort, _ := strconv.Atoi(destPortStr)
+		h.Lock()
+		h.forwards[addr] = ln
+		h.Unlock()
+		go func() {
+			<-ctx.Done()
+			h.Lock()
+			ln, ok := h.forwards[addr]
+			h.Unlock()
+			if ok {
+				ln.Close()
+			}
+		}()
+		go func() {
+			for {
+				c, err := ln.Accept()
+				if err != nil {
+					// TODO: log accept failure
+					break
+				}
+				originAddr, orignPortStr, _ := net.SplitHostPort(c.RemoteAddr().String())
+				originPort, _ := strconv.Atoi(orignPortStr)
+				payload := gossh.Marshal(&remoteForwardChannelData{
+					DestAddr:   reqPayload.BindAddr,
+					DestPort:   uint32(destPort),
+					OriginAddr: originAddr,
+					OriginPort: uint32(originPort),
+				})
+				go func() {
+					ch, reqs, err := conn.OpenChannel(forwardedTCPChannelType, payload)
+					if err != nil {
+						// TODO: log failure to open channel
+						log.Println(err)
+						c.Close()
+						return
+					}
+					go gossh.DiscardRequests(reqs)
+					go func() {
+						defer ch.Close()
+						defer c.Close()
+						io.Copy(ch, c)
+					}()
+					go func() {
+						defer ch.Close()
+						defer c.Close()
+						io.Copy(c, ch)
+					}()
+				}()
+			}
+			h.Lock()
+			delete(h.forwards, addr)
+			h.Unlock()
+		}()
+		return true, gossh.Marshal(&remoteForwardSuccess{uint32(destPort)})
+
+	case "cancel-tcpip-forward":
+		var reqPayload remoteForwardCancelRequest
+		if err := gossh.Unmarshal(req.Payload, &reqPayload); err != nil {
+			// TODO: log parse failure
+			return false, []byte{}
+		}
+		addr := net.JoinHostPort(reqPayload.BindAddr, strconv.Itoa(int(reqPayload.BindPort)))
+		h.Lock()
+		ln, ok := h.forwards[addr]
+		h.Unlock()
+		if ok {
+			ln.Close()
+		}
+		return true, nil
+	default:
+		return false, nil
+	}
+}

vendor/github.com/gliderlabs/ssh/util.go

@@ -0,0 +1,83 @@
+package ssh
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+	"encoding/binary"
+
+	"golang.org/x/crypto/ssh"
+)
+
+func generateSigner() (ssh.Signer, error) {
+	key, err := rsa.GenerateKey(rand.Reader, 2048)
+	if err != nil {
+		return nil, err
+	}
+	return ssh.NewSignerFromKey(key)
+}
+
+func parsePtyRequest(s []byte) (pty Pty, ok bool) {
+	term, s, ok := parseString(s)
+	if !ok {
+		return
+	}
+	width32, s, ok := parseUint32(s)
+	if !ok {
+		return
+	}
+	height32, _, ok := parseUint32(s)
+	if !ok {
+		return
+	}
+	pty = Pty{
+		Term: term,
+		Window: Window{
+			Width:  int(width32),
+			Height: int(height32),
+		},
+	}
+	return
+}
+
+func parseWinchRequest(s []byte) (win Window, ok bool) {
+	width32, s, ok := parseUint32(s)
+	if width32 < 1 {
+		ok = false
+	}
+	if !ok {
+		return
+	}
+	height32, _, ok := parseUint32(s)
+	if height32 < 1 {
+		ok = false
+	}
+	if !ok {
+		return
+	}
+	win = Window{
+		Width:  int(width32),
+		Height: int(height32),
+	}
+	return
+}
+
+func parseString(in []byte) (out string, rest []byte, ok bool) {
+	if len(in) < 4 {
+		return
+	}
+	length := binary.BigEndian.Uint32(in)
+	if uint32(len(in)) < 4+length {
+		return
+	}
+	out = string(in[4 : 4+length])
+	rest = in[4+length:]
+	ok = true
+	return
+}
+
+func parseUint32(in []byte) (uint32, []byte, bool) {
+	if len(in) < 4 {
+		return 0, nil, false
+	}
+	return binary.BigEndian.Uint32(in), in[4:], true
+}

vendor/github.com/gliderlabs/ssh/wrap.go

@@ -0,0 +1,33 @@
+package ssh
+
+import gossh "golang.org/x/crypto/ssh"
+
+// PublicKey is an abstraction of different types of public keys.
+type PublicKey interface {
+	gossh.PublicKey
+}
+
+// The Permissions type holds fine-grained permissions that are specific to a
+// user or a specific authentication method for a user. Permissions, except for
+// "source-address", must be enforced in the server application layer, after
+// successful authentication.
+type Permissions struct {
+	*gossh.Permissions
+}
+
+// A Signer can create signatures that verify against a public key.
+type Signer interface {
+	gossh.Signer
+}
+
+// ParseAuthorizedKey parses a public key from an authorized_keys file used in
+// OpenSSH according to the sshd(8) manual page.
+func ParseAuthorizedKey(in []byte) (out PublicKey, comment string, options []string, rest []byte, err error) {
+	return gossh.ParseAuthorizedKey(in)
+}
+
+// ParsePublicKey parses an SSH public key formatted for use in
+// the SSH wire protocol according to RFC 4253, section 6.6.
+func ParsePublicKey(in []byte) (out PublicKey, err error) {
+	return gossh.ParsePublicKey(in)
+}

vendor/golang.org/x/sys/unix/syscall_linux.go

@@ -13,7 +13,6 @@ package unix
 
 import (
 	"encoding/binary"
-	"net"
 	"runtime"
 	"syscall"
 	"unsafe"
@@ -765,7 +764,7 @@ const px_proto_oe = 0
 
 type SockaddrPPPoE struct {
 	SID    uint16
-	Remote net.HardwareAddr
+	Remote []byte
 	Dev    string
 	raw    RawSockaddrPPPoX
 }
@@ -916,7 +915,7 @@ func anyToSockaddr(fd int, rsa *RawSockaddrAny) (Sockaddr, error) {
 		}
 		sa := &SockaddrPPPoE{
 			SID:    binary.BigEndian.Uint16(pp[6:8]),
-			Remote: net.HardwareAddr(pp[8:14]),
+			Remote: pp[8:14],
 		}
 		for i := 14; i < 14+IFNAMSIZ; i++ {
 			if pp[i] == 0 {

vendor/golang.org/x/sys/unix/types_netbsd.go

@@ -254,6 +254,7 @@ type Ptmget C.struct_ptmget
 
 const (
 	AT_FDCWD            = C.AT_FDCWD
+	AT_SYMLINK_FOLLOW   = C.AT_SYMLINK_FOLLOW
 	AT_SYMLINK_NOFOLLOW = C.AT_SYMLINK_NOFOLLOW
 )
 

vendor/golang.org/x/sys/unix/types_openbsd.go

@@ -241,6 +241,7 @@ type Winsize C.struct_winsize
 
 const (
 	AT_FDCWD            = C.AT_FDCWD
+	AT_SYMLINK_FOLLOW   = C.AT_SYMLINK_FOLLOW
 	AT_SYMLINK_NOFOLLOW = C.AT_SYMLINK_NOFOLLOW
 )
 

vendor/golang.org/x/sys/unix/ztypes_netbsd_386.go

@@ -411,6 +411,7 @@ type Ptmget struct {
 
 const (
 	AT_FDCWD            = -0x64
+	AT_SYMLINK_FOLLOW   = 0x400
 	AT_SYMLINK_NOFOLLOW = 0x200
 )
 

vendor/golang.org/x/sys/unix/ztypes_netbsd_amd64.go

@@ -418,6 +418,7 @@ type Ptmget struct {
 
 const (
 	AT_FDCWD            = -0x64
+	AT_SYMLINK_FOLLOW   = 0x400
 	AT_SYMLINK_NOFOLLOW = 0x200
 )
 

vendor/golang.org/x/sys/unix/ztypes_netbsd_arm.go

@@ -416,6 +416,7 @@ type Ptmget struct {
 
 const (
 	AT_FDCWD            = -0x64
+	AT_SYMLINK_FOLLOW   = 0x400
 	AT_SYMLINK_NOFOLLOW = 0x200
 )
 

vendor/golang.org/x/sys/unix/ztypes_netbsd_arm64.go

@@ -418,6 +418,7 @@ type Ptmget struct {
 
 const (
 	AT_FDCWD            = -0x64
+	AT_SYMLINK_FOLLOW   = 0x400
 	AT_SYMLINK_NOFOLLOW = 0x200
 )
 

vendor/golang.org/x/sys/unix/ztypes_openbsd_386.go

@@ -436,6 +436,7 @@ type Winsize struct {
 
 const (
 	AT_FDCWD            = -0x64
+	AT_SYMLINK_FOLLOW   = 0x4
 	AT_SYMLINK_NOFOLLOW = 0x2
 )
 

vendor/golang.org/x/sys/unix/ztypes_openbsd_amd64.go

@@ -436,6 +436,7 @@ type Winsize struct {
 
 const (
 	AT_FDCWD            = -0x64
+	AT_SYMLINK_FOLLOW   = 0x4
 	AT_SYMLINK_NOFOLLOW = 0x2
 )
 

vendor/golang.org/x/sys/unix/ztypes_openbsd_arm.go

@@ -437,6 +437,7 @@ type Winsize struct {
 
 const (
 	AT_FDCWD            = -0x64
+	AT_SYMLINK_FOLLOW   = 0x4
 	AT_SYMLINK_NOFOLLOW = 0x2
 )
 

vendor/golang.org/x/sys/unix/ztypes_openbsd_arm64.go

@@ -430,6 +430,7 @@ type Winsize struct {
 
 const (
 	AT_FDCWD            = -0x64
+	AT_SYMLINK_FOLLOW   = 0x4
 	AT_SYMLINK_NOFOLLOW = 0x2
 )
 

vendor/golang.org/x/sys/windows/syscall_windows.go

@@ -294,7 +294,7 @@ func NewCallbackCDecl(fn interface{}) uintptr {
 //sys	clsidFromString(lpsz *uint16, pclsid *GUID) (ret error) = ole32.CLSIDFromString
 //sys	stringFromGUID2(rguid *GUID, lpsz *uint16, cchMax int32) (chars int32) = ole32.StringFromGUID2
 //sys	coCreateGuid(pguid *GUID) (ret error) = ole32.CoCreateGuid
-//sys	coTaskMemFree(address unsafe.Pointer) = ole32.CoTaskMemFree
+//sys	CoTaskMemFree(address unsafe.Pointer) = ole32.CoTaskMemFree
 //sys	rtlGetVersion(info *OsVersionInfoEx) (ret error) = ntdll.RtlGetVersion
 
 // syscall interface implementation for other packages
@@ -1302,7 +1302,7 @@ func (t Token) KnownFolderPath(folderID *KNOWNFOLDERID, flags uint32) (string, e
 	if err != nil {
 		return "", err
 	}
-	defer coTaskMemFree(unsafe.Pointer(p))
+	defer CoTaskMemFree(unsafe.Pointer(p))
 	return UTF16ToString((*[(1 << 30) - 1]uint16)(unsafe.Pointer(p))[:]), nil
 }
 

vendor/golang.org/x/sys/windows/zsyscall_windows.go

@@ -2517,7 +2517,7 @@ func coCreateGuid(pguid *GUID) (ret error) {
 	return
 }
 
-func coTaskMemFree(address unsafe.Pointer) {
+func CoTaskMemFree(address unsafe.Pointer) {
 	syscall.Syscall(procCoTaskMemFree.Addr(), 1, uintptr(address), 0, 0)
 	return
 }

vendor/modules.txt

@@ -15,6 +15,8 @@ github.com/Unknwon/i18n
 github.com/Unknwon/paginater
 # github.com/andybalholm/cascadia v0.0.0-20161224141413-349dd0209470
 github.com/andybalholm/cascadia
+# github.com/anmitsu/go-shlex v0.0.0-20161002113705-648efa622239
+github.com/anmitsu/go-shlex
 # github.com/beorn7/perks v1.0.0
 github.com/beorn7/perks/quantile
 # github.com/blevesearch/bleve v0.0.0-20190214220507-05d86ea8f6e3
@@ -112,6 +114,8 @@ github.com/facebookgo/grace/gracenet
 github.com/facebookgo/httpdown
 # github.com/facebookgo/stats v0.0.0-20151006221625-1b76add642e4
 github.com/facebookgo/stats
+# github.com/gliderlabs/ssh v0.2.2
+github.com/gliderlabs/ssh
 # github.com/glycerine/go-unsnap-stream v0.0.0-20180323001048-9f0cb55181dd
 github.com/glycerine/go-unsnap-stream
 # github.com/go-macaron/binding v0.0.0-20160711225916-9440f336b443
@@ -353,7 +357,7 @@ golang.org/x/crypto/cast5
 golang.org/x/crypto/openpgp/elgamal
 golang.org/x/crypto/ssh/knownhosts
 golang.org/x/crypto/ssh/agent
-# golang.org/x/net v0.0.0-20190613194153-d28f0bde5980
+# golang.org/x/net v0.0.0-20190619014844-b5b0513f8c1b
 golang.org/x/net/html/charset
 golang.org/x/net/html
 golang.org/x/net/html/atom
@@ -365,7 +369,7 @@ golang.org/x/net/internal/socks
 # golang.org/x/oauth2 v0.0.0-20181101160152-c453e0c75759
 golang.org/x/oauth2
 golang.org/x/oauth2/internal
-# golang.org/x/sys v0.0.0-20190618155005-516e3c20635f
+# golang.org/x/sys v0.0.0-20190620070143-6f217b454f45
 golang.org/x/sys/windows
 golang.org/x/sys/windows/svc
 golang.org/x/sys/unix