/
sftp.go
337 lines (284 loc) · 9.07 KB
/
sftp.go
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package main
// sftp server integration tests
// enable with -integration
// example invokation (darwin): gofmt -w `find . -name \*.go` && (cd server_standalone/ ; go build -tags debug) && go test -tags debug github.com/pkg/sftp -integration -v -sftp /usr/libexec/sftp-server -run ServerCompareSubsystems
import (
"encoding/hex"
"flag"
"fmt"
"io/ioutil"
"net"
"os"
"log"
"strings"
"github.com/pkg/sftp"
"golang.org/x/crypto/ssh"
)
var testSftpClientBin = flag.String("sftp_client", "/usr/bin/sftp", "location of the sftp client binary")
var sshServerDebugStream = ioutil.Discard
var sftpServerDebugStream = ioutil.Discard
var sftpClientDebugStream = ioutil.Discard
const (
GOLANG_SFTP = true
OPENSSH_SFTP = false
)
/***********************************************************************************************
SSH server scaffolding; very simple, no strict auth. This is for unit testing, not real servers
***********************************************************************************************/
var (
hostPrivateKeySigner ssh.Signer
privKey = []byte(`
-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----
`)
)
func init() {
var err error
hostPrivateKeySigner, err = ssh.ParsePrivateKey(privKey)
if err != nil {
panic(err)
}
}
func keyAuth(conn ssh.ConnMetadata, key ssh.PublicKey) (*ssh.Permissions, error) {
permissions := &ssh.Permissions{
CriticalOptions: map[string]string{},
Extensions: map[string]string{},
}
return permissions, nil
}
func pwAuth(conn ssh.ConnMetadata, pw []byte) (*ssh.Permissions, error) {
permissions := &ssh.Permissions{
CriticalOptions: map[string]string{},
Extensions: map[string]string{},
}
return permissions, nil
}
func basicServerConfig() *ssh.ServerConfig {
config := ssh.ServerConfig{
Config: ssh.Config{
MACs: []string{"hmac-sha1"},
},
PasswordCallback: pwAuth,
PublicKeyCallback: keyAuth,
}
config.AddHostKey(hostPrivateKeySigner)
return &config
}
type sshServer struct {
useSubsystem bool
conn net.Conn
config *ssh.ServerConfig
sshConn *ssh.ServerConn
newChans <-chan ssh.NewChannel
newReqs <-chan *ssh.Request
}
func sshServerFromConn(conn net.Conn, useSubsystem bool, config *ssh.ServerConfig) (*sshServer, error) {
// From a standard TCP connection to an encrypted SSH connection
sshConn, newChans, newReqs, err := ssh.NewServerConn(conn, config)
if err != nil {
return nil, err
}
svr := &sshServer{useSubsystem, conn, config, sshConn, newChans, newReqs}
svr.listenChannels()
return svr, nil
}
func (svr *sshServer) Wait() error {
return svr.sshConn.Wait()
}
func (svr *sshServer) Close() error {
return svr.sshConn.Close()
}
func (svr *sshServer) listenChannels() {
go func() {
for chanReq := range svr.newChans {
go svr.handleChanReq(chanReq)
}
}()
go func() {
for req := range svr.newReqs {
go svr.handleReq(req)
}
}()
}
func (svr *sshServer) handleReq(req *ssh.Request) {
switch req.Type {
default:
rejectRequest(req)
}
}
type sshChannelServer struct {
svr *sshServer
chanReq ssh.NewChannel
ch ssh.Channel
newReqs <-chan *ssh.Request
}
type sshSessionChannelServer struct {
*sshChannelServer
env []string
}
func (svr *sshServer) handleChanReq(chanReq ssh.NewChannel) {
fmt.Fprintf(sshServerDebugStream, "channel request: %v, extra: '%v'\n", chanReq.ChannelType(), hex.EncodeToString(chanReq.ExtraData()))
switch chanReq.ChannelType() {
case "session":
if ch, reqs, err := chanReq.Accept(); err != nil {
fmt.Fprintf(sshServerDebugStream, "fail to accept channel request: %v\n", err)
chanReq.Reject(ssh.ResourceShortage, "channel accept failure")
} else {
chsvr := &sshSessionChannelServer{
sshChannelServer: &sshChannelServer{svr, chanReq, ch, reqs},
env: append([]string{}, os.Environ()...),
}
chsvr.handle()
}
default:
chanReq.Reject(ssh.UnknownChannelType, "channel type is not a session")
}
}
func (chsvr *sshSessionChannelServer) handle() {
// should maybe do something here...
go chsvr.handleReqs()
}
func (chsvr *sshSessionChannelServer) handleReqs() {
for req := range chsvr.newReqs {
chsvr.handleReq(req)
}
fmt.Fprintf(sshServerDebugStream, "ssh server session channel complete\n")
}
func (chsvr *sshSessionChannelServer) handleReq(req *ssh.Request) {
switch req.Type {
case "env":
chsvr.handleEnv(req)
case "subsystem":
chsvr.handleSubsystem(req)
default:
rejectRequest(req)
}
}
func rejectRequest(req *ssh.Request) error {
fmt.Fprintf(sshServerDebugStream, "ssh rejecting request, type: %s\n", req.Type)
err := req.Reply(false, []byte{})
if err != nil {
fmt.Fprintf(sshServerDebugStream, "ssh request reply had error: %v\n", err)
}
return err
}
func rejectRequestUnmarshalError(req *ssh.Request, s interface{}, err error) error {
fmt.Fprintf(sshServerDebugStream, "ssh request unmarshaling error, type '%T': %v\n", s, err)
rejectRequest(req)
return err
}
// env request form:
type sshEnvRequest struct {
Envvar string
Value string
}
func (chsvr *sshSessionChannelServer) handleEnv(req *ssh.Request) error {
envReq := &sshEnvRequest{}
if err := ssh.Unmarshal(req.Payload, envReq); err != nil {
return rejectRequestUnmarshalError(req, envReq, err)
}
req.Reply(true, nil)
found := false
for i, envstr := range chsvr.env {
if strings.HasPrefix(envstr, envReq.Envvar+"=") {
found = true
chsvr.env[i] = envReq.Envvar + "=" + envReq.Value
}
}
if !found {
chsvr.env = append(chsvr.env, envReq.Envvar+"="+envReq.Value)
}
return nil
}
// Payload: int: command size, string: command
type sshSubsystemRequest struct {
Name string
}
type sshSubsystemExitStatus struct {
Status uint32
}
func (chsvr *sshSessionChannelServer) handleSubsystem(req *ssh.Request) error {
defer func() {
err1 := chsvr.ch.CloseWrite()
err2 := chsvr.ch.Close()
fmt.Fprintf(sshServerDebugStream, "ssh server subsystem request complete, err: %v %v\n", err1, err2)
}()
subsystemReq := &sshSubsystemRequest{}
if err := ssh.Unmarshal(req.Payload, subsystemReq); err != nil {
return rejectRequestUnmarshalError(req, subsystemReq, err)
}
// reply to the ssh client
// no idea if this is actually correct spec-wise.
// just enough for an sftp server to start.
if subsystemReq.Name == "sftp" {
req.Reply(true, nil)
sftpServer, err := sftp.NewServer(chsvr.ch, chsvr.ch, sftpServerDebugStream, 0, false, ".")
if err != nil {
return err
}
// wait for the session to close
runErr := sftpServer.Serve()
exitStatus := uint32(1)
if runErr == nil {
exitStatus = uint32(0)
}
_, exitStatusErr := chsvr.ch.SendRequest("exit-status", false, ssh.Marshal(sshSubsystemExitStatus{exitStatus}))
return exitStatusErr
} else {
return req.Reply(false, nil)
}
}
/***********************************************************************************************
Actual unit tests
***********************************************************************************************/
// starts an ssh server to test. returns: host string and port
func main() {
listener, err := net.Listen("tcp", "127.0.0.1:0")
if err != nil {
log.Fatal(err)
}
log.Println(listener.Addr().String())
func() {
for {
conn, err := listener.Accept()
if err != nil {
fmt.Fprintf(sshServerDebugStream, "ssh server socket closed\n")
break
}
go func() {
defer conn.Close()
sshSvr, err := sshServerFromConn(conn, true, basicServerConfig())
if err != nil {
log.Fatal(err)
}
err = sshSvr.Wait()
fmt.Fprintf(sshServerDebugStream, "ssh server finished, err: %v\n", err)
}()
}
}()
}