func main() {
var (
readOnly bool
debugStderr bool
)
flag.BoolVar(&readOnly, "R", false, "read-only server")
flag.BoolVar(&debugStderr, "e", false, "debug to stderr")
flag.Parse()
debugStream := ioutil.Discard
if debugStderr {
debugStream = os.Stderr
}
svr, _ := sftp.NewServer(
os.Stdin,
os.Stdout,
"",
sftp.WithDebug(debugStream),
sftp.ReadOnly(),
)
if err := svr.Serve(); err != nil {
fmt.Fprintf(debugStream, "sftp server completed with error: %v", err)
os.Exit(1)
}
}
func main() {
var (
readOnly bool
debugStderr bool
debugLevel string
)
flag.BoolVar(&readOnly, "R", false, "read-only server")
flag.BoolVar(&debugStderr, "e", false, "debug to stderr")
flag.StringVar(&debugLevel, "l", "none", "debug level (ignored)")
flag.Parse()
debugStream := ioutil.Discard
if debugStderr {
debugStream = os.Stderr
}
svr, _ := sftp.NewServer(
struct {
io.Reader
io.WriteCloser
}{os.Stdin,
os.Stdout,
},
sftp.WithDebug(debugStream),
sftp.ReadOnly(),
)
if err := svr.Serve(); err != nil {
fmt.Fprintf(debugStream, "sftp server completed with error: %v", err)
os.Exit(1)
}
}
func (sess *session) handleSubsystemRequest(request *ssh.Request) {
logger := sess.logger.Session("handle-subsystem-request")
logger.Info("starting")
defer logger.Info("finished")
type subsysMsg struct {
Subsystem string
}
var subsystemMessage subsysMsg
err := ssh.Unmarshal(request.Payload, &subsystemMessage)
if err != nil {
logger.Error("unmarshal-failed", err)
if request.WantReply {
request.Reply(false, nil)
}
return
}
if subsystemMessage.Subsystem != "sftp" {
logger.Info("unsupported-subsystem", lager.Data{"subsystem": subsystemMessage.Subsystem})
if request.WantReply {
request.Reply(false, nil)
}
return
}
lagerWriter := helpers.NewLagerWriter(logger.Session("sftp-server"))
sftpServer, err := sftp.NewServer(sess.channel, sess.channel, sftp.WithDebug(lagerWriter))
if err != nil {
logger.Error("sftp-new-server-failed", err)
if request.WantReply {
request.Reply(false, nil)
}
return
}
if request.WantReply {
request.Reply(true, nil)
}
logger.Info("starting-server")
go func() {
defer sess.destroy()
err = sftpServer.Serve()
if err != nil {
logger.Error("sftp-serve-error", err)
}
}()
}
// Based on example server code from golang.org/x/crypto/ssh and server_standalone from github.com/pkg/sftp
func main() {
var (
readOnly bool
debugStderr bool
authUser, authPassword string
addr string
rootDir string
)
flag.BoolVar(&readOnly, "ro", true, "read-only server")
flag.BoolVar(&debugStderr, "d", false, "debug to stderr")
flag.StringVar(&addr, "addr", "0.0.0.0:2022", "address for server to listen on")
flag.StringVar(&authUser, "usr", "testuser", "user name to require for authentication")
flag.StringVar(&authPassword, "pwd", "tiger", "password to require for authentication")
flag.StringVar(&rootDir, "dir", "", "root directory to serve from")
flag.Parse()
debugStream = ioutil.Discard
if debugStderr {
debugStream = os.Stderr
}
// An SSH server is represented by a ServerConfig, which holds
// certificate details and handles authentication of ServerConns.
config := &ssh.ServerConfig{
PasswordCallback: func(c ssh.ConnMetadata, pass []byte) (*ssh.Permissions, error) {
debug("Login: %s", c.User())
if c.User() == authUser && string(pass) == authPassword {
return nil, nil
}
return nil, fmt.Errorf("password rejected for %q", c.User())
},
}
privateBytes, err := ioutil.ReadFile("id_rsa")
if err != nil {
log.Fatal("failed to load private key", err)
}
private, err := ssh.ParsePrivateKey(privateBytes)
if err != nil {
log.Fatal("failed to parse private key", err)
}
config.AddHostKey(private)
// Once a ServerConfig has been configured, connections can be
// accepted.
listener, err := net.Listen("tcp", addr)
if err != nil {
log.Fatal("failed to listen for connection", err)
}
log.Printf("Listening on %v\n", listener.Addr())
for {
nConn, err := listener.Accept()
if err != nil {
log.Printf("failed to accept incoming connection: %v\n", err)
continue
}
// Before use, a handshake must be performed on the incoming
// net.Conn.
_, chans, reqs, err := ssh.NewServerConn(nConn, config)
if err != nil {
log.Printf("failed to handshake: %v\n", err)
continue
}
debug("SSH server established")
// The incoming Request channel must be serviced.
go ssh.DiscardRequests(reqs)
// Service the incoming Channel channel.
for newChannel := range chans {
// Channels have a type, depending on the application level
// protocol intended. In the case of an SFTP session, this is "subsystem"
// with a payload string of "<length=4>sftp"
debug("Incoming channel: %s", newChannel.ChannelType())
if newChannel.ChannelType() != "session" {
newChannel.Reject(ssh.UnknownChannelType, "unknown channel type")
debug("Unknown channel type: %s", newChannel.ChannelType())
continue
}
channel, requests, err := newChannel.Accept()
if err != nil {
log.Printf("could not accept channel: %v\n", err)
continue
}
debug("Channel accepted")
// Sessions have out-of-band requests such as "shell",
// "pty-req" and "env". Here we handle only the
// "subsystem" request.
go func(in <-chan *ssh.Request) {
for req := range in {
debug("Request: %v", req.Type)
ok := false
switch req.Type {
case "subsystem":
debug("Subsystem: %s", req.Payload[4:])
if string(req.Payload[4:]) == "sftp" {
ok = true
}
}
debug(" - accepted: %v", ok)
req.Reply(ok, nil)
}
}(requests)
options := append([]sftp.ServerOption{}, sftp.WithDebug(debugStream))
options = append(options, sftp.WithRootDir(rootDir))
if readOnly {
options = append(options, sftp.ReadOnly())
}
server, err := sftp.NewServer(channel, channel, options...)
if err != nil {
log.Printf("cannot start server: %v\n", err)
continue
}
if err := server.Serve(); err != nil && err != io.EOF {
log.Printf("server completed with error: %v\n", err)
continue
}
}
}
}
// Based on example server code from golang.org/x/crypto/ssh and server_standalone
func main() {
var (
readOnly bool
debugStderr bool
)
flag.BoolVar(&readOnly, "R", false, "read-only server")
flag.BoolVar(&debugStderr, "e", false, "debug to stderr")
flag.Parse()
debugStream := ioutil.Discard
if debugStderr {
debugStream = os.Stderr
}
// An SSH server is represented by a ServerConfig, which holds
// certificate details and handles authentication of ServerConns.
config := &ssh.ServerConfig{
PasswordCallback: func(c ssh.ConnMetadata, pass []byte) (*ssh.Permissions, error) {
// Should use constant-time compare (or better, salt+hash) in
// a production setting.
fmt.Fprintf(debugStream, "Login: %s\n", c.User())
if c.User() == "testuser" && string(pass) == "tiger" {
return nil, nil
}
return nil, fmt.Errorf("password rejected for %q", c.User())
},
}
privateBytes, err := ioutil.ReadFile("id_rsa")
if err != nil {
log.Fatal("Failed to load private key", err)
}
private, err := ssh.ParsePrivateKey(privateBytes)
if err != nil {
log.Fatal("Failed to parse private key", err)
}
config.AddHostKey(private)
// Once a ServerConfig has been configured, connections can be
// accepted.
listener, err := net.Listen("tcp", "0.0.0.0:2022")
if err != nil {
log.Fatal("failed to listen for connection", err)
}
fmt.Printf("Listening on %v\n", listener.Addr())
nConn, err := listener.Accept()
if err != nil {
log.Fatal("failed to accept incoming connection", err)
}
// Before use, a handshake must be performed on the incoming
// net.Conn.
_, chans, reqs, err := ssh.NewServerConn(nConn, config)
if err != nil {
log.Fatal("failed to handshake", err)
}
fmt.Fprintf(debugStream, "SSH server established\n")
// The incoming Request channel must be serviced.
go ssh.DiscardRequests(reqs)
// Service the incoming Channel channel.
for newChannel := range chans {
// Channels have a type, depending on the application level
// protocol intended. In the case of an SFTP session, this is "subsystem"
// with a payload string of "<length=4>sftp"
fmt.Fprintf(debugStream, "Incoming channel: %s\n", newChannel.ChannelType())
if newChannel.ChannelType() != "session" {
newChannel.Reject(ssh.UnknownChannelType, "unknown channel type")
fmt.Fprintf(debugStream, "Unknown channel type: %s\n", newChannel.ChannelType())
continue
}
channel, requests, err := newChannel.Accept()
if err != nil {
log.Fatal("could not accept channel.", err)
}
fmt.Fprintf(debugStream, "Channel accepted\n")
// Sessions have out-of-band requests such as "shell",
// "pty-req" and "env". Here we handle only the
// "subsystem" request.
go func(in <-chan *ssh.Request) {
for req := range in {
fmt.Fprintf(debugStream, "Request: %v\n", req.Type)
ok := false
switch req.Type {
case "subsystem":
fmt.Fprintf(debugStream, "Subsystem: %s\n", req.Payload[4:])
if string(req.Payload[4:]) == "sftp" {
ok = true
}
}
fmt.Fprintf(debugStream, " - accepted: %v\n", ok)
req.Reply(ok, nil)
}
}(requests)
server, err := sftp.NewServer(
channel,
channel,
sftp.WithDebug(debugStream),
sftp.ReadOnly(),
)
if err != nil {
log.Fatal(err)
}
if err := server.Serve(); err != nil {
log.Fatal("sftp server completed with error:", err)
}
}
}