func newServerShell(ch *ServerChan, prompt string) *ServerTerminal {
term := terminal.NewTerminal(ch, prompt)
return &ServerTerminal{
Term: term,
Channel: ch,
}
}
func sshHandleChannel(conn net.Conn, newChannel ssh.NewChannel) {
// Channels have a type, depending on the application level protocol
// intended. In the case of a shell, the type is "session" and ServerShell
// may be used to present a simple terminal interface.
if newChannel.ChannelType() != "session" {
newChannel.Reject(ssh.UnknownChannelType, "unknown channel type")
return
}
channel, requests, err := newChannel.Accept()
if err != nil {
log.Errorln(err)
return
}
// Sessions have out-of-band requests such as "shell", "pty-req" and "env".
// Here we handle only the "shell" request.
go func(in <-chan *ssh.Request) {
for req := range in {
ok := false
switch req.Type {
case "shell":
ok = true
if len(req.Payload) > 0 {
// We don't accept any commands, only the default shell.
ok = false
}
case "pty-req":
ok = true
}
req.Reply(ok, nil)
}
}(requests)
term := terminal.NewTerminal(channel, "> ")
go func() {
defer channel.Close()
for {
line, err := term.ReadLine()
start := time.Now().UnixNano()
if err != nil {
if err != io.EOF {
log.Errorln(err)
}
return
}
sshReportChan <- uint64(len(line))
// just echo the message
log.Debugln("ssh received: ", line)
term.Write([]byte(line))
term.Write([]byte{'\r', '\n'})
stop := time.Now().UnixNano()
log.Info("ssh %v %vns", conn.RemoteAddr(), uint64(stop-start))
}
}()
}
func sshHandleConn(conn *ssh.ServerConn) {
for {
channel, err := conn.Accept()
if err != nil {
if err != io.EOF {
log.Errorln(err)
}
return
}
if channel.ChannelType() != "session" {
channel.Reject(ssh.UnknownChannelType, "unknown channel type")
continue
}
channel.Accept()
term := terminal.NewTerminal(channel, "> ")
serverTerm := &ssh.ServerTerminal{
Term: term,
Channel: channel,
}
go func() {
defer channel.Close()
for {
line, err := serverTerm.ReadLine()
start := time.Now().UnixNano()
if err != nil {
if err != io.EOF {
log.Errorln(err)
}
return
}
sshReportChan <- uint64(len(line))
// just echo the message
log.Debugln("ssh received: ", line)
serverTerm.Write([]byte(line))
serverTerm.Write([]byte{'\r', '\n'})
stop := time.Now().UnixNano()
log.Info("ssh %v %vns", conn.RemoteAddr(), uint64(stop-start))
}
}()
}
}
func ExampleNewServerConn() {
// 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.
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 {
panic("Failed to load private key")
}
private, err := ssh.ParsePrivateKey(privateBytes)
if err != nil {
panic("Failed to parse private key")
}
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 {
panic("failed to listen for connection")
}
nConn, err := listener.Accept()
if err != nil {
panic("failed to accept incoming connection")
}
// Before use, a handshake must be performed on the incoming
// net.Conn.
_, chans, reqs, err := ssh.NewServerConn(nConn, config)
if err != nil {
panic("failed to handshake")
}
// 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 a shell, the type is
// "session" and ServerShell may be used to present a simple
// terminal interface.
if newChannel.ChannelType() != "session" {
newChannel.Reject(ssh.UnknownChannelType, "unknown channel type")
continue
}
channel, requests, err := newChannel.Accept()
if err != nil {
panic("could not accept channel.")
}
// Sessions have out-of-band requests such as "shell",
// "pty-req" and "env". Here we handle only the
// "shell" request.
go func(in <-chan *ssh.Request) {
for req := range in {
ok := false
switch req.Type {
case "shell":
ok = true
if len(req.Payload) > 0 {
// We don't accept any
// commands, only the
// default shell.
ok = false
}
}
req.Reply(ok, nil)
}
}(requests)
term := terminal.NewTerminal(channel, "> ")
go func() {
defer channel.Close()
for {
line, err := term.ReadLine()
if err != nil {
break
}
fmt.Println(line)
}
}()
}
}
func newServerShell(ch Channel, in <-chan *Request, prompt string) *terminal.Terminal {
term := terminal.NewTerminal(ch, prompt)
go handleTerminalRequests(in)
return term
}
func ExampleListen() {
// An SSH server is represented by a ServerConfig, which holds
// certificate details and handles authentication of ServerConns.
config := &ServerConfig{
PasswordCallback: func(conn *ServerConn, user, pass string) bool {
return user == "testuser" && pass == "tiger"
},
}
pemBytes, err := ioutil.ReadFile("id_rsa")
if err != nil {
panic("Failed to load private key")
}
if err = config.SetRSAPrivateKey(pemBytes); err != nil {
panic("Failed to parse private key")
}
// Once a ServerConfig has been configured, connections can be
// accepted.
listener, err := Listen("tcp", "0.0.0.0:2022", config)
if err != nil {
panic("failed to listen for connection")
}
sConn, err := listener.Accept()
if err != nil {
panic("failed to accept incoming connection")
}
if err := sConn.Handshake(); err != nil {
panic("failed to handshake")
}
// A ServerConn multiplexes several channels, which must
// themselves be Accepted.
for {
// Accept reads from the connection, demultiplexes packets
// to their corresponding channels and returns when a new
// channel request is seen. Some goroutine must always be
// calling Accept; otherwise no messages will be forwarded
// to the channels.
channel, err := sConn.Accept()
if err != nil {
panic("error from Accept")
}
// Channels have a type, depending on the application level
// protocol intended. In the case of a shell, the type is
// "session" and ServerShell may be used to present a simple
// terminal interface.
if channel.ChannelType() != "session" {
channel.Reject(UnknownChannelType, "unknown channel type")
continue
}
channel.Accept()
term := terminal.NewTerminal(channel, "> ")
serverTerm := &ServerTerminal{
Term: term,
Channel: channel,
}
go func() {
defer channel.Close()
for {
line, err := serverTerm.ReadLine()
if err != nil {
break
}
fmt.Println(line)
}
}()
}
}
