add shell/exec support on server

pty_unix.go

@@ -0,0 +1,14 @@
+// +build linux
+
+package obfssh
+
+import (
+	"io"
+	"os/exec"
+
+	"github.com/kr/pty"
+)
+
+func startPty(cmd *exec.Cmd) (io.ReadWriteCloser, error) {
+	return pty.Start(cmd)
+}

pty_windows.go

@@ -0,0 +1,11 @@
+package obfssh
+
+import (
+	"errors"
+	"io"
+	"os/exec"
+)
+
+func startPty(cmd *exec.Cmd) (io.ReadWriteCloser, error) {
+	return nil, errors.New("not implement")
+}

server.go

@@ -2,7 +2,11 @@ package obfssh
 
 import (
 	"fmt"
+	"io"
 	"net"
+	"os/exec"
+	"runtime"
+	"syscall"
 	"time"
 
 	"github.com/fangdingjun/go-log"
@@ -130,6 +134,15 @@ type args struct {
 	Arg string
 }
 
+type envArgs struct {
+	Name  string
+	Value string
+}
+
+type exitStatus struct {
+	Status uint32
+}
+
 func (sc *Server) handleSession(newch ssh.NewChannel) {
 	ch, req, err := newch.Accept()
 	if err != nil {
@@ -137,27 +150,69 @@ func (sc *Server) handleSession(newch ssh.NewChannel) {
 		return
 	}
 
-	var cmd args
+	var _cmd args
 
 	ret := false
+	var cmd *exec.Cmd
+	var env []string
 
 	for r := range req {
 		switch r.Type {
 		case "subsystem":
-			if err := ssh.Unmarshal(r.Payload, &cmd); err != nil {
+			if err := ssh.Unmarshal(r.Payload, &_cmd); err == nil {
-				ret = false
+				if _cmd.Arg == "sftp" { // only support sftp
+					ret = true
+					log.Debugf("handle sftp request")
+					go serveSFTP(ch)
+				} else {
+					log.Debugln("subsystem", _cmd.Arg, "not support")
+				}
 			} else {
-				if cmd.Arg != "sftp" { // only support sftp
 				ret = false
+				log.Debugln("get subsystem arg error", err)
+			}
+		case "shell":
+			ret = true
+			if runtime.GOOS == "windows" {
+				cmd = exec.Command("powershell")
 			} else {
-
+				cmd = exec.Command("bash", "-l")
+			}
+			cmd.Env = env
+			go handleShell(cmd, ch)
+		case "signal":
+			log.Debugln("got signal")
 			ret = true
-
+		case "exec":
-					log.Debugf("handle sftp request")
+			ret = true
-
+			if err = ssh.Unmarshal(r.Payload, &_cmd); err == nil {
-					go serveSFTP(ch)
+				log.Debugln("execute command", _cmd.Arg)
+				if runtime.GOOS == "windows" {
+					cmd = exec.Command("powershell", "-Command", _cmd.Arg)
+				} else {
+					cmd = exec.Command("bash", "-c", _cmd.Arg)
+				}
+				cmd.Env = env
+				//cmd.Stdin = ch
+				go handleCommand(cmd, ch)
+			} else {
+				log.Debugln(err)
+				ret = false
 			}
+		case "pty-req":
+			ret = true
+		case "env":
+			var arg envArgs
+			ret = true
+			if err = ssh.Unmarshal(r.Payload, &arg); err == nil {
+				log.Debugf("got env %s=%s", arg.Name, arg.Value)
+				env = append(env, fmt.Sprintf("%s=%s", arg.Name, arg.Value))
+			} else {
+				log.Debugln("parse env failed", err)
+				ret = false
 			}
+		case "window-change":
+			ret = true
 		default:
 			ret = false
 		}
@@ -170,6 +225,92 @@ func (sc *Server) handleSession(newch ssh.NewChannel) {
 	}
 }
 
+func handleShell(cmd *exec.Cmd, ch ssh.Channel) {
+	defer ch.Close()
+
+	var _pty io.ReadWriteCloser
+	var err error
+
+	log.Debugln("start shell")
+
+	//_pty, err = pty.Start(cmd)
+	if runtime.GOOS == "unix" || runtime.GOOS == "linux" {
+		_pty, err = startPty(cmd)
+		if err != nil {
+			log.Debugln("start pty", err)
+			ch.SendRequest("exit-status", false,
+				ssh.Marshal(exitStatus{Status: 127}))
+			return
+		}
+	}
+
+	if runtime.GOOS == "unix" || runtime.GOOS == "linux" {
+		defer _pty.Close()
+		go io.Copy(ch, _pty)
+		go io.Copy(_pty, ch)
+	} else { // windows
+		cmd.Stderr = ch
+		cmd.Stdout = ch
+		in, err := cmd.StdinPipe()
+		if err != nil {
+			ch.SendRequest("exit-status", false,
+				ssh.Marshal(exitStatus{Status: 127}))
+			return
+		}
+		go func() {
+			defer in.Close()
+			io.Copy(in, ch)
+		}()
+		if err := cmd.Start(); err != nil {
+			log.Debugln("start command ", err)
+			ch.SendRequest("exit-status", false,
+				ssh.Marshal(exitStatus{Status: 126}))
+			return
+		}
+	}
+	code := 0
+	if err = cmd.Wait(); err != nil {
+		log.Debugln(err)
+		if exiterr, ok := err.(*exec.ExitError); ok {
+			if s, ok := exiterr.Sys().(syscall.WaitStatus); ok {
+				code = s.ExitStatus()
+			}
+		}
+	}
+	ch.SendRequest("exit-status", false,
+		ssh.Marshal(exitStatus{Status: uint32(code)}))
+}
+
+func handleCommand(cmd *exec.Cmd, ch ssh.Channel) {
+	defer ch.Close()
+
+	cmd.Stdout = ch
+	cmd.Stderr = ch
+	//log.Debugln("execute command", cmd)
+	in, err := cmd.StdinPipe()
+	if err != nil {
+		log.Debugln(err)
+		ch.SendRequest("exit-status", false,
+			ssh.Marshal(exitStatus{Status: 127}))
+		return
+	}
+	go func() {
+		defer in.Close()
+		io.Copy(in, ch)
+	}()
+	code := 0
+	if err := cmd.Run(); err != nil {
+		log.Debugln(err)
+		if exiterr, ok := err.(*exec.ExitError); ok {
+			if s, ok := exiterr.Sys().(syscall.WaitStatus); ok {
+				code = s.ExitStatus()
+			}
+		}
+	}
+	ch.SendRequest("exit-status", false,
+		ssh.Marshal(exitStatus{Status: uint32(code)}))
+}
+
 func handleDirectTcpip(newch ssh.NewChannel) {
 	var r directTcpipMsg