"syscall"
"git.arvados.org/arvados.git/lib/selfsigned"
+ "git.arvados.org/arvados.git/sdk/go/ctxlog"
"git.arvados.org/arvados.git/sdk/go/httpserver"
"github.com/creack/pty"
"github.com/google/shlex"
"golang.org/x/crypto/ssh"
+ "golang.org/x/net/context"
)
+type GatewayTarget interface {
+ // Command that will execute cmd inside the container
+ InjectCommand(ctx context.Context, detachKeys, username string, usingTTY bool, cmd []string) (*exec.Cmd, error)
+
+ // IP address inside container
+ IPAddress() (string, error)
+}
+
+type GatewayTargetStub struct{}
+
+func (GatewayTargetStub) IPAddress() (string, error) { return "127.0.0.1", nil }
+func (GatewayTargetStub) InjectCommand(ctx context.Context, detachKeys, username string, usingTTY bool, cmd []string) (*exec.Cmd, error) {
+ return exec.CommandContext(ctx, cmd[0], cmd[1:]...), nil
+}
+
type Gateway struct {
- DockerContainerID *string
- ContainerUUID string
- Address string // listen host:port; if port=0, Start() will change it to the selected port
- AuthSecret string
- Log interface {
+ ContainerUUID string
+ Address string // listen host:port; if port=0, Start() will change it to the selected port
+ AuthSecret string
+ Target GatewayTarget
+ Log interface {
Printf(fmt string, args ...interface{})
}
defer conn.Close()
go ssh.DiscardRequests(reqs)
for newch := range newchans {
- if newch.ChannelType() != "session" {
- newch.Reject(ssh.UnknownChannelType, fmt.Sprintf("unsupported channel type %q", newch.ChannelType()))
- continue
- }
- ch, reqs, err := newch.Accept()
- if err != nil {
- gw.Log.Printf("accept channel: %s", err)
- return
+ switch newch.ChannelType() {
+ case "direct-tcpip":
+ go gw.handleDirectTCPIP(ctx, newch)
+ case "session":
+ go gw.handleSession(ctx, newch, detachKeys, username)
+ default:
+ go newch.Reject(ssh.UnknownChannelType, fmt.Sprintf("unsupported channel type %q", newch.ChannelType()))
}
- var pty0, tty0 *os.File
- go func() {
- // Where to send errors/messages for the
- // client to see
- logw := io.Writer(ch.Stderr())
- // How to end lines when sending
- // errors/messages to the client (changes to
- // \r\n when using a pty)
- eol := "\n"
- // Env vars to add to child process
- termEnv := []string(nil)
- for req := range reqs {
- ok := false
- switch req.Type {
- case "shell", "exec":
- ok = true
- var payload struct {
- Command string
- }
- ssh.Unmarshal(req.Payload, &payload)
- execargs, err := shlex.Split(payload.Command)
- if err != nil {
- fmt.Fprintf(logw, "error parsing supplied command: %s"+eol, err)
- return
- }
- if len(execargs) == 0 {
- execargs = []string{"/bin/bash", "-login"}
- }
- go func() {
- cmd := exec.CommandContext(ctx, "docker", "exec", "-i", "--detach-keys="+detachKeys, "--user="+username)
- cmd.Stdin = ch
- cmd.Stdout = ch
- cmd.Stderr = ch.Stderr()
- if tty0 != nil {
- cmd.Args = append(cmd.Args, "-t")
- cmd.Stdin = tty0
- cmd.Stdout = tty0
- cmd.Stderr = tty0
- var wg sync.WaitGroup
- defer wg.Wait()
- wg.Add(2)
- go func() { io.Copy(ch, pty0); wg.Done() }()
- go func() { io.Copy(pty0, ch); wg.Done() }()
- // Send our own debug messages to tty as well.
- logw = tty0
- }
- cmd.Args = append(cmd.Args, *gw.DockerContainerID)
- cmd.Args = append(cmd.Args, execargs...)
- cmd.SysProcAttr = &syscall.SysProcAttr{
- Setctty: tty0 != nil,
- Setsid: true,
- }
- cmd.Env = append(os.Environ(), termEnv...)
- err := cmd.Run()
- var resp struct {
- Status uint32
- }
- if exiterr, ok := err.(*exec.ExitError); ok {
- if status, ok := exiterr.Sys().(syscall.WaitStatus); ok {
- resp.Status = uint32(status.ExitStatus())
- }
- } else if err != nil {
- // Propagate errors like `exec: "docker": executable file not found in $PATH`
- fmt.Fprintln(ch.Stderr(), err)
- }
- errClose := ch.CloseWrite()
- if resp.Status == 0 && (err != nil || errClose != nil) {
- resp.Status = 1
- }
- ch.SendRequest("exit-status", false, ssh.Marshal(&resp))
- ch.Close()
- }()
- case "pty-req":
- eol = "\r\n"
- p, t, err := pty.Open()
- if err != nil {
- fmt.Fprintf(ch.Stderr(), "pty failed: %s"+eol, err)
- break
- }
- defer p.Close()
- defer t.Close()
- pty0, tty0 = p, t
- ok = true
- var payload struct {
- Term string
- Cols uint32
- Rows uint32
- X uint32
- Y uint32
- }
- ssh.Unmarshal(req.Payload, &payload)
- termEnv = []string{"TERM=" + payload.Term, "USE_TTY=1"}
- err = pty.Setsize(pty0, &pty.Winsize{Rows: uint16(payload.Rows), Cols: uint16(payload.Cols), X: uint16(payload.X), Y: uint16(payload.Y)})
- if err != nil {
- fmt.Fprintf(logw, "pty-req: setsize failed: %s"+eol, err)
- }
- case "window-change":
- var payload struct {
- Cols uint32
- Rows uint32
- X uint32
- Y uint32
- }
- ssh.Unmarshal(req.Payload, &payload)
- err := pty.Setsize(pty0, &pty.Winsize{Rows: uint16(payload.Rows), Cols: uint16(payload.Cols), X: uint16(payload.X), Y: uint16(payload.Y)})
- if err != nil {
- fmt.Fprintf(logw, "window-change: setsize failed: %s"+eol, err)
- break
+ }
+}
+
+func (gw *Gateway) handleDirectTCPIP(ctx context.Context, newch ssh.NewChannel) {
+ ch, reqs, err := newch.Accept()
+ if err != nil {
+ gw.Log.Printf("accept direct-tcpip channel: %s", err)
+ return
+ }
+ defer ch.Close()
+ go ssh.DiscardRequests(reqs)
+
+ // RFC 4254 7.2 (copy of channelOpenDirectMsg in
+ // golang.org/x/crypto/ssh)
+ var msg struct {
+ Raddr string
+ Rport uint32
+ Laddr string
+ Lport uint32
+ }
+ err = ssh.Unmarshal(newch.ExtraData(), &msg)
+ if err != nil {
+ fmt.Fprintf(ch.Stderr(), "unmarshal direct-tcpip extradata: %s\n", err)
+ return
+ }
+ switch msg.Raddr {
+ case "localhost", "0.0.0.0", "127.0.0.1", "::1", "::":
+ default:
+ fmt.Fprintf(ch.Stderr(), "cannot forward to ports on %q, only localhost\n", msg.Raddr)
+ return
+ }
+
+ dstaddr, err := gw.Target.IPAddress()
+ if err != nil {
+ fmt.Fprintf(ch.Stderr(), "container has no IP address: %s\n", err)
+ return
+ } else if dstaddr == "" {
+ fmt.Fprintf(ch.Stderr(), "container has no IP address\n")
+ return
+ }
+
+ dst := net.JoinHostPort(dstaddr, fmt.Sprintf("%d", msg.Rport))
+ tcpconn, err := net.Dial("tcp", dst)
+ if err != nil {
+ fmt.Fprintf(ch.Stderr(), "%s: %s\n", dst, err)
+ return
+ }
+ go func() {
+ n, _ := io.Copy(ch, tcpconn)
+ ctxlog.FromContext(ctx).Debugf("tcpip: sent %d bytes\n", n)
+ ch.CloseWrite()
+ }()
+ n, _ := io.Copy(tcpconn, ch)
+ ctxlog.FromContext(ctx).Debugf("tcpip: received %d bytes\n", n)
+}
+
+func (gw *Gateway) handleSession(ctx context.Context, newch ssh.NewChannel, detachKeys, username string) {
+ ch, reqs, err := newch.Accept()
+ if err != nil {
+ gw.Log.Printf("accept session channel: %s", err)
+ return
+ }
+ var pty0, tty0 *os.File
+ // Where to send errors/messages for the client to see
+ logw := io.Writer(ch.Stderr())
+ // How to end lines when sending errors/messages to the client
+ // (changes to \r\n when using a pty)
+ eol := "\n"
+ // Env vars to add to child process
+ termEnv := []string(nil)
+ for req := range reqs {
+ ok := false
+ switch req.Type {
+ case "shell", "exec":
+ ok = true
+ var payload struct {
+ Command string
+ }
+ ssh.Unmarshal(req.Payload, &payload)
+ execargs, err := shlex.Split(payload.Command)
+ if err != nil {
+ fmt.Fprintf(logw, "error parsing supplied command: %s"+eol, err)
+ return
+ }
+ if len(execargs) == 0 {
+ execargs = []string{"/bin/bash", "-login"}
+ }
+ go func() {
+ var resp struct {
+ Status uint32
+ }
+ defer func() {
+ ch.SendRequest("exit-status", false, ssh.Marshal(&resp))
+ ch.Close()
+ }()
+
+ cmd, err := gw.Target.InjectCommand(ctx, detachKeys, username, tty0 != nil, execargs)
+ if err != nil {
+ fmt.Fprintln(ch.Stderr(), err)
+ ch.CloseWrite()
+ resp.Status = 1
+ return
+ }
+ cmd.Stdin = ch
+ cmd.Stdout = ch
+ cmd.Stderr = ch.Stderr()
+ if tty0 != nil {
+ cmd.Stdin = tty0
+ cmd.Stdout = tty0
+ cmd.Stderr = tty0
+ var wg sync.WaitGroup
+ defer wg.Wait()
+ wg.Add(2)
+ go func() { io.Copy(ch, pty0); wg.Done() }()
+ go func() { io.Copy(pty0, ch); wg.Done() }()
+ // Send our own debug messages to tty as well.
+ logw = tty0
+ }
+ cmd.SysProcAttr = &syscall.SysProcAttr{
+ Setctty: tty0 != nil,
+ Setsid: true,
+ }
+ cmd.Env = append(os.Environ(), termEnv...)
+ err = cmd.Run()
+ if exiterr, ok := err.(*exec.ExitError); ok {
+ if status, ok := exiterr.Sys().(syscall.WaitStatus); ok {
+ resp.Status = uint32(status.ExitStatus())
}
- ok = true
- case "env":
- // TODO: implement "env"
- // requests by setting env
- // vars in the docker-exec
- // command (not docker-exec's
- // own environment, which
- // would be a gaping security
- // hole).
- default:
- // fmt.Fprintf(logw, "declining %q req"+eol, req.Type)
+ } else if err != nil {
+ // Propagate errors like `exec: "docker": executable file not found in $PATH`
+ fmt.Fprintln(ch.Stderr(), err)
}
- if req.WantReply {
- req.Reply(ok, nil)
+ errClose := ch.CloseWrite()
+ if resp.Status == 0 && (err != nil || errClose != nil) {
+ resp.Status = 1
}
+ }()
+ case "pty-req":
+ eol = "\r\n"
+ p, t, err := pty.Open()
+ if err != nil {
+ fmt.Fprintf(ch.Stderr(), "pty failed: %s"+eol, err)
+ break
+ }
+ defer p.Close()
+ defer t.Close()
+ pty0, tty0 = p, t
+ ok = true
+ var payload struct {
+ Term string
+ Cols uint32
+ Rows uint32
+ X uint32
+ Y uint32
+ }
+ ssh.Unmarshal(req.Payload, &payload)
+ termEnv = []string{"TERM=" + payload.Term, "USE_TTY=1"}
+ err = pty.Setsize(pty0, &pty.Winsize{Rows: uint16(payload.Rows), Cols: uint16(payload.Cols), X: uint16(payload.X), Y: uint16(payload.Y)})
+ if err != nil {
+ fmt.Fprintf(logw, "pty-req: setsize failed: %s"+eol, err)
+ }
+ case "window-change":
+ var payload struct {
+ Cols uint32
+ Rows uint32
+ X uint32
+ Y uint32
}
- }()
+ ssh.Unmarshal(req.Payload, &payload)
+ err := pty.Setsize(pty0, &pty.Winsize{Rows: uint16(payload.Rows), Cols: uint16(payload.Cols), X: uint16(payload.X), Y: uint16(payload.Y)})
+ if err != nil {
+ fmt.Fprintf(logw, "window-change: setsize failed: %s"+eol, err)
+ break
+ }
+ ok = true
+ case "env":
+ // TODO: implement "env"
+ // requests by setting env
+ // vars in the docker-exec
+ // command (not docker-exec's
+ // own environment, which
+ // would be a gaping security
+ // hole).
+ default:
+ // fmt.Fprintf(logw, "declining %q req"+eol, req.Type)
+ }
+ if req.WantReply {
+ req.Reply(ok, nil)
+ }
}
}
projects / arvados.git / blobdiff