// HandleChannel handles one SSH channel
func (c *Client) HandleChannel(newChannel ssh.NewChannel) error {
if newChannel.ChannelType() != "session" {
logrus.Debugf("Unknown channel type: %s", newChannel.ChannelType())
newChannel.Reject(ssh.UnknownChannelType, "unknown channel type")
return nil
}
channel, requests, err := newChannel.Accept()
if err != nil {
logrus.Errorf("newChannel.Accept failed: %v", err)
return err
}
c.ChannelIdx++
logrus.Debugf("HandleChannel.channel (client=%d channel=%d): %v", c.Idx, c.ChannelIdx, channel)
logrus.Debug("Creating pty...")
f, tty, err := pty.Open()
if err != nil {
logrus.Errorf("pty.Open failed: %v", err)
return nil
}
c.Tty = tty
c.Pty = f
c.HandleChannelRequests(channel, requests)
return nil
}
// KeyboardInteractiveCallback is called after PublicKeyCallback
func (s *Server) KeyboardInteractiveCallback(conn ssh.ConnMetadata, challenge ssh.KeyboardInteractiveChallenge) (*ssh.Permissions, error) {
username := conn.User()
clientID := conn.RemoteAddr().String()
logrus.Debugf("KeyboardInteractiveCallback: %q %q", username, challenge)
config := s.ClientConfigs[clientID]
if config == nil {
s.ClientConfigs[clientID] = &ClientConfig{
RemoteUser: username,
ImageName: username,
Keys: []string{},
Env: make(Environment, 0),
}
}
config = s.ClientConfigs[clientID]
if len(config.Keys) == 0 {
logrus.Warnf("No user keys, continuing with password authentication")
return nil, s.CheckConfig(config)
}
if s.PublicKeyAuthScript != "" {
logrus.Debugf("%d keys received, trying to authenticate using hook script", len(config.Keys))
script, err := expandUser(s.PublicKeyAuthScript)
if err != nil {
logrus.Warnf("Failed to expandUser: %v", err)
return nil, err
}
args := append([]string{username}, config.Keys...)
cmd := exec.Command(script, args...)
// FIXME: redirect stderr to logrus
cmd.Stderr = os.Stderr
output, err := cmd.Output()
if err != nil {
logrus.Warnf("Failed to execute publickey-auth-script: %v", err)
return nil, err
}
err = json.Unmarshal(output, &config)
if err != nil {
logrus.Warnf("Failed to unmarshal json %q: %v", string(output), err)
return nil, err
}
} else {
logrus.Debugf("%d keys received, but no hook script, continuing", len(config.Keys))
}
return nil, s.CheckConfig(config)
}
// Handle is the SSH client entrypoint, it takes a net.Conn
// instance and handle all the ssh and ssh2docker stuff
func (s *Server) Handle(netConn net.Conn) error {
if err := s.Init(); err != nil {
return err
}
logrus.Debugf("Server.Handle netConn=%v", netConn)
// Initialize a Client object
conn, chans, reqs, err := ssh.NewServerConn(netConn, s.SshConfig)
if err != nil {
return err
}
client := NewClient(conn, chans, reqs, s)
client.Config = s.ClientConfigs[conn.RemoteAddr().String()]
client.Config.Env.ApplyDefaults()
// Handle requests
if err = client.HandleRequests(); err != nil {
return err
}
// Handle channels
if err = client.HandleChannels(); err != nil {
return err
}
return nil
}
// DockerRemove removes a container
func DockerRemove(containerID string) error {
cmd := exec.Command("docker", "rm", "-f", containerID)
_, err := cmd.CombinedOutput()
if err != nil {
return err
}
logrus.Debugf("Deleted container: %q", containerID)
return nil
}
// DockerKill kills a container
func DockerKill(containerID string) error {
cmd := exec.Command("docker", "kill", "-s", "9", containerID)
_, err := cmd.CombinedOutput()
if err != nil {
return err
}
logrus.Debugf("Killed container: %q", containerID)
return nil
}
// HandleRequests handles SSH requests
func (c *Client) HandleRequests() error {
go func(in <-chan *ssh.Request) {
for req := range in {
logrus.Debugf("HandleRequest: %v", req)
if req.WantReply {
req.Reply(false, nil)
}
}
}(c.Reqs)
return nil
}
// PasswordCallback is called when the user tries to authenticate using a password
func (s *Server) PasswordCallback(conn ssh.ConnMetadata, password []byte) (*ssh.Permissions, error) {
username := conn.User()
clientID := conn.RemoteAddr().String()
logrus.Debugf("PasswordCallback: %q %q", username, password)
config := s.ClientConfigs[clientID]
if config == nil {
s.ClientConfigs[clientID] = &ClientConfig{
//Allowed: true,
RemoteUser: username,
ImageName: username,
Keys: []string{},
Env: make(Environment, 0),
}
}
config = s.ClientConfigs[clientID]
if s.PasswordAuthScript != "" {
script, err := expandUser(s.PasswordAuthScript)
if err != nil {
logrus.Warnf("Failed to expandUser: %v", err)
return nil, err
}
cmd := exec.Command(script, username, string(password))
// FIXME: redirect stderr to logrus
cmd.Stderr = os.Stderr
output, err := cmd.Output()
if err != nil {
logrus.Warnf("Failed to execute password-auth-script: %v", err)
return nil, err
}
err = json.Unmarshal(output, &config)
if err != nil {
logrus.Warnf("Failed to unmarshal json %q: %v", string(output), err)
return nil, err
}
}
return nil, s.CheckConfig(config)
}
// PublicKeyCallback is called when the user tries to authenticate using an SSH public key
func (s *Server) PublicKeyCallback(conn ssh.ConnMetadata, key ssh.PublicKey) (*ssh.Permissions, error) {
username := conn.User()
clientID := conn.RemoteAddr().String()
keyText := strings.TrimSpace(string(ssh.MarshalAuthorizedKey(key)))
logrus.Debugf("PublicKeyCallback: %q %q", username, keyText)
// sessionID := conn.SessionID()
config := s.ClientConfigs[clientID]
if config == nil {
s.ClientConfigs[clientID] = &ClientConfig{
RemoteUser: username,
ImageName: username,
Keys: []string{},
Env: make(Environment, 0),
}
}
config = s.ClientConfigs[clientID]
config.Keys = append(config.Keys, keyText)
return nil, s.CheckConfig(config)
}
// HandleChannelRequests handles channel requests
func (c *Client) HandleChannelRequests(channel ssh.Channel, requests <-chan *ssh.Request) {
go func(in <-chan *ssh.Request) {
defer c.Tty.Close()
for req := range in {
ok := false
switch req.Type {
case "shell":
logrus.Debugf("HandleChannelRequests.req shell")
if len(req.Payload) != 0 {
break
}
ok = true
var cmd *exec.Cmd
var err error
if c.Config.IsLocal {
cmd = exec.Command("/bin/bash")
} else {
// checking if a container already exists for this user
existingContainer := ""
if !c.Server.NoJoin {
cmd := exec.Command("docker", "ps", "--filter=label=ssh2docker", fmt.Sprintf("--filter=label=image=%s", c.Config.ImageName), fmt.Sprintf("--filter=label=user=%s", c.Config.RemoteUser), "--quiet", "--no-trunc")
cmd.Env = c.Config.Env.List()
buf, err := cmd.CombinedOutput()
if err != nil {
logrus.Warnf("docker ps ... failed: %v", err)
continue
}
existingContainer = strings.TrimSpace(string(buf))
}
// Opening Docker process
if existingContainer != "" {
// Attaching to an existing container
shell := c.Server.DefaultShell
if c.Config.EntryPoint != "" {
shell = c.Config.EntryPoint
}
args := []string{"exec", "-it", existingContainer, shell}
logrus.Debugf("Executing 'docker %s'", strings.Join(args, " "))
cmd = exec.Command("docker", args...)
cmd.Env = c.Config.Env.List()
} else {
// Creating and attaching to a new container
args := []string{"run"}
args = append(args, c.Server.DockerRunArgs...)
args = append(args, "--label=ssh2docker", fmt.Sprintf("--label=user=%s", c.Config.RemoteUser), fmt.Sprintf("--label=image=%s", c.Config.ImageName))
if c.Config.User != "" {
args = append(args, "-u", c.Config.User)
}
if c.Config.EntryPoint != "" {
args = append(args, "--entrypoint", c.Config.EntryPoint)
}
args = append(args, c.Config.ImageName)
if c.Config.Command != nil {
args = append(args, c.Config.Command...)
} else {
args = append(args, c.Server.DefaultShell)
}
logrus.Debugf("Executing 'docker %s'", strings.Join(args, " "))
cmd = exec.Command("docker", args...)
cmd.Env = c.Config.Env.List()
}
}
if c.Server.Banner != "" {
banner := c.Server.Banner
banner = strings.Replace(banner, "\r", "", -1)
banner = strings.Replace(banner, "\n", "\n\r", -1)
fmt.Fprintf(channel, "%s\n\r", banner)
}
cmd.Stdout = c.Tty
cmd.Stdin = c.Tty
cmd.Stderr = c.Tty
cmd.SysProcAttr = &syscall.SysProcAttr{
Setctty: true,
Setsid: true,
}
err = cmd.Start()
if err != nil {
logrus.Warnf("cmd.Start failed: %v", err)
continue
}
var once sync.Once
close := func() {
channel.Close()
logrus.Debug("session closed")
}
go func() {
io.Copy(channel, c.Pty)
once.Do(close)
}()
go func() {
io.Copy(c.Pty, channel)
once.Do(close)
}()
go func() {
if err := cmd.Wait(); err != nil {
logrus.Warnf("cmd.Wait failed: %v", err)
}
once.Do(close)
}()
case "exec":
command := string(req.Payload)
logrus.Debugf("HandleChannelRequests.req exec: %q", command)
ok = false
fmt.Fprintln(channel, "⚠️ ssh2docker: exec is not yet implemented. https://github.com/moul/ssh2docker/issues/51.")
time.Sleep(3 * time.Second)
case "pty-req":
ok = true
termLen := req.Payload[3]
c.Config.Env["TERM"] = string(req.Payload[4 : termLen+4])
w, h := parseDims(req.Payload[termLen+4:])
SetWinsize(c.Pty.Fd(), w, h)
logrus.Debugf("HandleChannelRequests.req pty-req: TERM=%q w=%q h=%q", c.Config.Env["TERM"], int(w), int(h))
case "window-change":
w, h := parseDims(req.Payload)
SetWinsize(c.Pty.Fd(), w, h)
continue
case "env":
keyLen := req.Payload[3]
key := string(req.Payload[4 : keyLen+4])
valueLen := req.Payload[keyLen+7]
value := string(req.Payload[keyLen+8 : keyLen+8+valueLen])
logrus.Debugf("HandleChannelRequets.req 'env': %s=%q", key, value)
c.Config.Env[key] = value
default:
logrus.Debugf("Unhandled request type: %q: %v", req.Type, req)
}
if req.WantReply {
if !ok {
logrus.Debugf("Declining %s request...", req.Type)
}
req.Reply(ok, nil)
}
}
}(requests)
}
func SetWinsize(fd uintptr, w, h uint32) {
logrus.Debugf("Window resize '%dx%d'", w, h)
ws := &Winsize{Width: uint16(w), Height: uint16(h)}
syscall.Syscall(syscall.SYS_IOCTL, fd, uintptr(syscall.TIOCSWINSZ), uintptr(unsafe.Pointer(ws)))
}