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// Copyright 2014 The Gogs Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.
package ssh
import (
"fmt"
"io"
"io/ioutil"
"net"
"os"
"os/exec"
"path/filepath"
"strings"
"github.com/Unknwon/com"
"golang.org/x/crypto/ssh"
"github.com/gogits/gogs/models"
"github.com/gogits/gogs/modules/log"
"github.com/gogits/gogs/modules/setting"
)
func cleanCommand(cmd string) string {
i := strings.Index(cmd, "git")
if i == -1 {
return cmd
}
return cmd[i:]
}
func handleServerConn(keyID string, chans <-chan ssh.NewChannel) {
for newChan := range chans {
if newChan.ChannelType() != "session" {
newChan.Reject(ssh.UnknownChannelType, "unknown channel type")
continue
}
ch, reqs, err := newChan.Accept()
if err != nil {
log.Error(3, "Error accepting channel: %v", err)
continue
}
go func(in <-chan *ssh.Request) {
defer ch.Close()
for req := range in {
payload := cleanCommand(string(req.Payload))
switch req.Type {
case "env":
args := strings.Split(strings.Replace(payload, "\x00", "", -1), "\v")
if len(args) != 2 {
log.Warn("Invalid env arguments: '%#v'", args)
continue
}
args[0] = strings.TrimLeft(args[0], "\x04")
_, _, err := com.ExecCmdBytes("env", args[0]+"="+args[1])
if err != nil {
log.Error(3, "env: %v", err)
return
}
case "exec":
cmdName := strings.TrimLeft(payload, "'()")
os.Setenv("SSH_ORIGINAL_COMMAND", cmdName)
log.Trace("Payload: %v", cmdName)
args := []string{"serv", "key-" + keyID, "--config=" + setting.CustomConf}
log.Trace("Arguments: %v", args)
cmd := exec.Command(setting.AppPath, args...)
stdout, err := cmd.StdoutPipe()
if err != nil {
log.Error(3, "StdoutPipe: %v", err)
return
}
stderr, err := cmd.StderrPipe()
if err != nil {
log.Error(3, "StderrPipe: %v", err)
return
}
input, err := cmd.StdinPipe()
if err != nil {
log.Error(3, "StdinPipe: %v", err)
return
}
// FIXME: check timeout
if err = cmd.Start(); err != nil {
log.Error(3, "Start: %v", err)
return
}
req.Reply(true, nil)
go io.Copy(input, ch)
io.Copy(ch, stdout)
io.Copy(ch.Stderr(), stderr)
if err = cmd.Wait(); err != nil {
log.Error(3, "Wait: %v", err)
return
}
ch.SendRequest("exit-status", false, []byte{0, 0, 0, 0})
return
default:
}
}
}(reqs)
}
}
func listen(config *ssh.ServerConfig, port int) {
listener, err := net.Listen("tcp", "0.0.0.0:"+com.ToStr(port))
if err != nil {
panic(err)
}
for {
// Once a ServerConfig has been configured, connections can be accepted.
conn, err := listener.Accept()
if err != nil {
log.Error(3, "Error accepting incoming connection: %v", err)
continue
}
// Before use, a handshake must be performed on the incoming net.Conn.
sConn, chans, reqs, err := ssh.NewServerConn(conn, config)
if err != nil {
log.Error(3, "Error on handshaking: %v", err)
continue
}
log.Trace("Connection from %s (%s)", sConn.RemoteAddr(), sConn.ClientVersion())
// The incoming Request channel must be serviced.
go ssh.DiscardRequests(reqs)
go handleServerConn(sConn.Permissions.Extensions["key-id"], chans)
}
}
// Listen starts a SSH server listens on given port.
func Listen(port int) {
config := &ssh.ServerConfig{
PublicKeyCallback: func(conn ssh.ConnMetadata, key ssh.PublicKey) (*ssh.Permissions, error) {
pkey, err := models.SearchPublicKeyByContent(strings.TrimSpace(string(ssh.MarshalAuthorizedKey(key))))
if err != nil {
log.Error(3, "SearchPublicKeyByContent: %v", err)
return nil, err
}
return &ssh.Permissions{Extensions: map[string]string{"key-id": com.ToStr(pkey.ID)}}, nil
},
}
keyPath := filepath.Join(setting.AppDataPath, "ssh/gogs.rsa")
if !com.IsExist(keyPath) {
os.MkdirAll(filepath.Dir(keyPath), os.ModePerm)
_, stderr, err := com.ExecCmd("ssh-keygen", "-f", keyPath, "-t", "rsa", "-N", "")
if err != nil {
panic(fmt.Sprintf("Fail to generate private key: %v - %s", err, stderr))
}
log.Trace("New private key is generateed: %s", keyPath)
}
privateBytes, err := ioutil.ReadFile(keyPath)
if err != nil {
panic("Fail to load private key")
}
private, err := ssh.ParsePrivateKey(privateBytes)
if err != nil {
panic("Fail to parse private key")
}
config.AddHostKey(private)
go listen(config, port)
}
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