Description

SSH2 client and server modules written in pure JavaScript for node.js.

Development/testing is done against OpenSSH (6.6 currently).

Changes from v0.3.x-v0.4.x

Requirements

• node.js -- v0.8.7 or newer

Install

npm install ssh2

Client Examples

• Authenticate using keys and execute uptime on a server:

var Client = require('ssh2').Client;

var conn = new Client();
conn.on('ready', function() {
  console.log('Client :: ready');
  conn.exec('uptime', function(err, stream) {
    if (err) throw err;
    stream.on('close', function(code, signal) {
      console.log('Stream :: close :: code: ' + code + ', signal: ' + signal);
      conn.end();
    }).on('data', function(data) {
      console.log('STDOUT: ' + data);
    }).stderr.on('data', function(data) {
      console.log('STDERR: ' + data);
    });
  });
}).connect({
  host: '192.168.100.100',
  port: 22,
  username: 'frylock',
  privateKey: require('fs').readFileSync('/here/is/my/key')
});

// example output:
// Client :: ready
// STDOUT:  17:41:15 up 22 days, 18:09,  1 user,  load average: 0.00, 0.01, 0.05
//
// Stream :: exit :: code: 0, signal: undefined
// Stream :: close

• Authenticate using keys and start an interactive shell session:

var Client = require('ssh2').Client;

var conn = new Client();
conn.on('ready', function() {
  console.log('Client :: ready');
  conn.shell(function(err, stream) {
    if (err) throw err;
    stream.on('close', function() {
      console.log('Stream :: close');
      conn.end();
    }).on('data', function(data) {
      console.log('STDOUT: ' + data);
    }).stderr.on('data', function(data) {
      console.log('STDERR: ' + data);
    });
    stream.end('ls -l\nexit\n');
  });
}).connect({
  host: '192.168.100.100',
  port: 22,
  username: 'frylock',
  privateKey: require('fs').readFileSync('/here/is/my/key')
});

// example output:
// Client :: ready
// STDOUT: Last login: Sun Jun 15 09:37:21 2014 from 192.168.100.100
//
// STDOUT: ls -l
// exit
//
// STDOUT: frylock@athf:~$ ls -l
//
// STDOUT: total 8
//
// STDOUT: drwxr-xr-x 2 frylock frylock 4096 Nov 18  2012 mydir
//
// STDOUT: -rw-r--r-- 1 frylock frylock   25 Apr 11  2013 test.txt
//
// STDOUT: frylock@athf:~$ exit
//
// STDOUT: logout
//
// Stream :: close

• Authenticate using password and send an HTTP request to port 80 on the server:

var Client = require('ssh2').Client;

var conn = new Client();
conn.on('ready', function() {
  console.log('Client :: ready');
  conn.forwardOut('192.168.100.102', 8000, '127.0.0.1', 80, function(err, stream) {
    if (err) throw err;
    stream.on('close', function() {
      console.log('TCP :: CLOSED');
      conn.end();
    }).on('data', function(data) {
      console.log('TCP :: DATA: ' + data);
    }).end([
      'HEAD / HTTP/1.1',
      'User-Agent: curl/7.27.0',
      'Host: 127.0.0.1',
      'Accept: */*',
      'Connection: close',
      '',
      ''
    ].join('\r\n'));
  });
}).connect({
  host: '192.168.100.100',
  port: 22,
  username: 'frylock',
  password: 'nodejsrules'
});

// example output:
// Client :: ready
// TCP :: DATA: HTTP/1.1 200 OK
// Date: Thu, 15 Nov 2012 13:52:58 GMT
// Server: Apache/2.2.22 (Ubuntu)
// X-Powered-By: PHP/5.4.6-1ubuntu1
// Last-Modified: Thu, 01 Jan 1970 00:00:00 GMT
// Content-Encoding: gzip
// Vary: Accept-Encoding
// Connection: close
// Content-Type: text/html; charset=UTF-8
//
//
// TCP :: CLOSED

• Authenticate using password and forward remote connections on port 8000 to us:

var Client = require('ssh2').Client;

var conn = new Client();
conn.on('ready', function() {
  console.log('Client :: ready');
  conn.forwardIn('127.0.0.1', 8000, function(err) {
    if (err) throw err;
    console.log('Listening for connections on server on port 8000!');
  });
}).on('tcp connection', function(info, accept, reject) {
  console.log('TCP :: INCOMING CONNECTION:');
  console.dir(info);
  accept().on('close', function() {
    console.log('TCP :: CLOSED');
  }).on('data', function(data) {
    console.log('TCP :: DATA: ' + data);
  }).end([
    'HTTP/1.1 404 Not Found',
    'Date: Thu, 15 Nov 2012 02:07:58 GMT',
    'Server: ForwardedConnection',
    'Content-Length: 0',
    'Connection: close',
    '',
    ''
  ].join('\r\n'));
}).connect({
  host: '192.168.100.100',
  port: 22,
  username: 'frylock',
  password: 'nodejsrules'
});

// example output:
// Client :: ready
// Listening for connections on server on port 8000!
//  (.... then from another terminal on the server: `curl -I http://127.0.0.1:8000`)
// TCP :: INCOMING CONNECTION: { destIP: '127.0.0.1',
//  destPort: 8000,
//  srcIP: '127.0.0.1',
//  srcPort: 41969 }
// TCP DATA: HEAD / HTTP/1.1
// User-Agent: curl/7.27.0
// Host: 127.0.0.1:8000
// Accept: */*
//
//
// TCP :: CLOSED

• Authenticate using password and get a directory listing via SFTP:

var Client = require('ssh2').Client;

var conn = new Client();
conn.on('ready', function() {
  console.log('Client :: ready');
  conn.sftp(function(err, sftp) {
    if (err) throw err;
    sftp.readdir('foo', function(err, list) {
      if (err) throw err;
      console.dir(list);
      conn.end();
    });
  });
}).connect({
  host: '192.168.100.100',
  port: 22,
  username: 'frylock',
  password: 'nodejsrules'
});

// example output:
// Client :: ready
// [ { filename: 'test.txt',
//     longname: '-rw-r--r--    1 frylock   frylock         12 Nov 18 11:05 test.txt',
//     attrs:
//      { size: 12,
//        uid: 1000,
//        gid: 1000,
//        mode: 33188,
//        atime: 1353254750,
//        mtime: 1353254744 } },
//   { filename: 'mydir',
//     longname: 'drwxr-xr-x    2 frylock   frylock       4096 Nov 18 15:03 mydir',
//     attrs:
//      { size: 1048576,
//        uid: 1000,
//        gid: 1000,
//        mode: 16877,
//        atime: 1353269007,
//        mtime: 1353269007 } } ]

• Connection hopping:

var Client = require('ssh2').Client;

var conn1 = new Client(),
    conn2 = new Client();

conn1.on('ready', function() {
  console.log('FIRST :: connection ready');
  conn1.exec('nc 192.168.1.2 22', function(err, stream) {
    if (err) {
      console.log('FIRST :: exec error: ' + err);
      return conn1.end();
    }
    conn2.connect({
      sock: stream,
      username: 'user2',
      password: 'password2',
    });
  });
}).connect({
  host: '192.168.1.1',
  username: 'user1',
  password: 'password1',
});

conn2.on('ready', function() {
  console.log('SECOND :: connection ready');
  conn2.exec('uptime', function(err, stream) {
    if (err) {
      console.log('SECOND :: exec error: ' + err);
      return conn1.end();
    }
    stream.on('end', function() {
      conn1.end(); // close parent (and this) connection
    }).on('data', function(data) {
      console.log(data.toString());
    });
  });
});

• Forward X11 connections (xeyes):

var net = require('net'),
    Client = require('ssh2').Client;

var conn = new Client();

conn.on('x11', function(info, accept, reject) {
  var xserversock = new net.Socket();
  xserversock.on('connect', function() {
    var xclientsock = accept();
    xclientsock.pipe(xserversock).pipe(xclientsock);
  });
  // connects to localhost:0.0
  xserversock.connect(6000, 'localhost');
});

conn.on('ready', function() {
  conn.exec('xeyes', { x11: true }, function(err, stream) {
    if (err) throw err;
    var code = 0;
    stream.on('end', function() {
      if (code !== 0)
        console.log('Do you have X11 forwarding enabled on your SSH server?');
      conn.end();
    }).on('exit', function(exitcode) {
      code = exitcode;
    });
  });
}).connect({
  host: '192.168.1.1',
  username: 'foo',
  password: 'bar'
});

• Dynamic (1:1) port forwarding using a SOCKSv5 proxy (using socksv5):

var socks = require('socksv5'),
    Client = require('ssh2').Client;

var ssh_config = {
  host: '192.168.100.1',
  port: 22,
  username: 'nodejs',
  password: 'rules'
};

socks.createServer(function(info, accept, deny) {
  // NOTE: you could just use one ssh2 client connection for all forwards, but
  // you could run into server-imposed limits if you have too many forwards open
  // at any given time
  var conn = new Client();
  conn.on('ready', function() {
    conn.forwardOut(info.srcAddr,
                    info.srcPort,
                    info.dstAddr,
                    info.dstPort,
                    function(err, stream) {
      if (err) {
        conn.end();
        return deny();
      }

      var clientSocket;
      if (clientSocket = accept(true)) {
        stream.pipe(clientSocket).pipe(stream).on('close', function() {
          conn.end();
        });
      } else
        conn.end();
    });
  }).on('error', function(err) {
    deny();
  }).connect(ssh_config);
}).listen(1080, 'localhost', function() {
  console.log('SOCKSv5 proxy server started on port 1080');
}).useAuth(socks.auth.None());

// test with cURL:
//   curl -i --socks5 localhost:1080 google.com

• Invoke an arbitrary subsystem (netconf in this example):

var Client = require('ssh2').Client,
    xmlhello = '<?xml version="1.0" encoding="UTF-8"?>'+
               '<hello xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">'+
               '    <capabilities>'+
               '		<capability>urn:ietf:params:netconf:base:1.0</capability>'+
               '	</capabilities>'+
               '</hello>]]>]]>';

var conn = new Client();

conn.on('ready', function() {
  console.log('Client :: ready');
  conn.subsys('netconf', function(err, stream) {
    if (err) throw err;
    stream.on('data', function(data) {
      console.log(data);
    }).write(xmlhello);
  });
}).connect({
  host: '1.2.3.4',
  port: 22,
  username: 'blargh',
  password: 'honk'
});

Server Examples

• Only allow password and public key authentication and command execution:

var fs = require('fs'),
    crypto = require('crypto'),
    inspect = require('util').inspect;
var buffersEqual = require('buffer-equal-constant-time'),
    ssh2 = require('ssh2'),
    utils = ssh2.utils;

var pubKey = utils.genPublicKey(utils.parseKey(fs.readFileSync('user.pub')));

new ssh2.Server({
  privateKey: fs.readFileSync('host.key')
}, function(client) {
  console.log('Client connected!');

  client.on('authentication', function(ctx) {
    if (ctx.method === 'password'
        && ctx.username === 'foo'
        && ctx.password === 'bar')
      ctx.accept();
    else if (ctx.method === 'publickey'
             && ctx.key.algo === pubKey.fulltype
             && buffersEqual(ctx.key.data, pubKey.public)) {
      if (ctx.signature) {
        var verifier = crypto.createVerify(ctx.sigAlgo);
        verifier.update(ctx.blob);
        if (verifier.verify(pubKey.publicOrig, ctx.signature, 'binary'))
          ctx.accept();
        else
          ctx.reject();
      } else {
        // if no signature present, that means the client is just checking
        // the validity of the given public key
        ctx.accept();
      }
    } else
      ctx.reject();
  }).on('ready', function() {
    console.log('Client authenticated!');

    client.on('session', function(accept, reject) {
      var session = accept();
      session.once('exec', function(accept, reject, info) {
        console.log('Client wants to execute: ' + inspect(info.command));
        var stream = accept();
        stream.stderr.write('Oh no, the dreaded errors!\n');
        stream.write('Just kidding about the errors!\n');
        stream.exit(0);
        stream.end();
      });
    });
  }).on('end', function() {
    console.log('Client disconnected');
  });
}).listen(0, '127.0.0.1', function() {
  console.log('Listening on port ' + this.address().port);
});

• SFTP only server:

var fs = require('fs');
var ssh2 = require('ssh2');
var OPEN_MODE = ssh2.SFTP_OPEN_MODE,
    STATUS_CODE = ssh2.SFTP_STATUS_CODE;

new ssh2.Server({
  privateKey: fs.readFileSync('host.key')
}, function(client) {
  console.log('Client connected!');

  client.on('authentication', function(ctx) {
    if (ctx.method === 'password'
        && ctx.username === 'foo'
        && ctx.password === 'bar')
      ctx.accept();
    else
      ctx.reject();
  }).on('ready', function() {
    console.log('Client authenticated!');

    client.on('session', function(accept, reject) {
      var session = accept();
      session.on('sftp', function(accept, reject) {
        console.log('Client SFTP session');
        var openFiles = {};
        var handleCount = 0;
        // `sftpStream` is an `SFTPStream` instance in server mode
        // see: https://github.com/mscdex/ssh2-streams/blob/master/SFTPStream.md
        var sftpStream = accept();
        sftpStream.on('OPEN', function(reqid, filename, flags, attrs) {
          // only allow opening /tmp/foo.txt for writing
          if (filename !== '/tmp/foo.txt' || !(flags & OPEN_MODE.WRITE))
            return sftpStream.status(reqid, STATUS_CODE.FAILURE);
          // create a fake handle to return to the client, this could easily
          // be a real file descriptor number for example if actually opening
          // the file on the disk
          var handle = new Buffer(4);
          openFiles[handleCount] = true;
          handle.writeUInt32BE(handleCount++, 0, true);
          sftpStream.handle(reqid, handle);
          console.log('Opening file for write')
        }).on('WRITE', function(reqid, handle, offset, data) {
          if (handle.length !== 4 || !openFiles[handle.readUInt32BE(0, true)])
            return sftpStream.status(reqid, STATUS_CODE.FAILURE);
          // fake the write
          sftpStream.status(reqid, STATUS_CODE.OK);
          var inspected = require('util').inspect(data);
          console.log('Write to file at offset %d: %s', offset, inspected);
        }).on('CLOSE', function(reqid, handle) {
          var fnum;
          if (handle.length !== 4 || !openFiles[(fnum = handle.readUInt32BE(0, true))])
            return sftpStream.status(reqid, STATUS_CODE.FAILURE);
          delete openFiles[fnum];
          sftpStream.status(reqid, STATUS_CODE.OK);
          console.log('Closing file');
        });
      });
    });
  }).on('end', function() {
    console.log('Client disconnected');
  });
}).listen(0, '127.0.0.1', function() {
  console.log('Listening on port ' + this.address().port);
});

API

require('ssh2').Client returns a Client constructor.

require('ssh2').Server returns a Server constructor.

require('ssh2').utils returns the utility methods from ssh2-streams.

require('ssh2').SFTP_STATUS_CODE returns the SFTPStream.STATUS_CODE from ssh2-streams.

require('ssh2').SFTP_OPEN_MODE returns the SFTPStream.OPEN_MODE from ssh2-streams.

Client events

• banner(< string >message, < string >language) - A notice was sent by the server upon connection.

• ready() - Authentication was successful.

• tcp connection(< object >details, < function >accept, < function >reject) - An incoming forwarded TCP connection is being requested. Calling accept accepts the connection and returns a Channel object. Calling reject rejects the connection and no further action is needed. details contains:

  • srcIP - string - The originating IP of the connection.

  • srcPort - integer - The originating port of the connection.

  • destIP - string - The remote IP the connection was received on (given in earlier call to forwardIn()).

  • destPort - integer - The remote port the connection was received on (given in earlier call to forwardIn()).

• x11(< object >details, < function >accept, < function >reject) - An incoming X11 connection is being requested. Calling accept accepts the connection and returns a Channel object. Calling reject rejects the connection and no further action is needed. details contains:

  • srcIP - string - The originating IP of the connection.

  • srcPort - integer - The originating port of the connection.

• keyboard-interactive(< string >name, < string >instructions, < string >instructionsLang, < array >prompts, < function >finish) - The server is asking for replies to the given prompts for keyboard-interactive user authentication. name is generally what you'd use as a window title (for GUI apps). prompts is an array of { prompt: 'Password: ', echo: false } style objects (here echo indicates whether user input should be displayed on the screen). The answers for all prompts must be provided as an array of strings and passed to finish when you are ready to continue. Note: It's possible for the server to come back and ask more questions.

• change password(< string >message, < string >language, < function >done) - If using password-based user authentication, the server has requested that the user's password be changed. Call done with the new password.

• continue() - Emitted when more requests/data can be sent to the server (after a Client method returned false).

• error(< Error >err) - An error occurred. A 'level' property indicates 'client-socket' for socket-level errors and 'client-ssh' for SSH disconnection messages. In the case of 'client-ssh' messages, there may be a 'description' property that provides more detail.

• end() - The socket was disconnected.

• close(< boolean >hadError) - The socket was closed. hadError is set to true if this was due to error.

Client methods

• (constructor)() - Creates and returns a new Client instance.

• connect(< object >config) - (void) - Attempts a connection to a server using the information given in config:

  • host - string - Hostname or IP address of the server. Default: 'localhost'

  • port - integer - Port number of the server. Default: 22

  • forceIPv4 - boolean - Only connect via resolved IPv4 address for host. Default: false

  • forceIPv6 - boolean - Only connect via resolved IPv6 address for host. Default: false

  • hostHash - string - 'md5' or 'sha1'. The host's key is hashed using this method and passed to the hostVerifier function. Default: (none)

  • hostVerifier - function - Function that is passed a string hex hash of the host's key for verification purposes. Return true to continue with the handshake or false to reject and disconnect. Default: (auto-accept)

  • username - string - Username for authentication. Default: (none)

  • password - string - Password for password-based user authentication. Default: (none)

  • agent - string - Path to ssh-agent's UNIX socket for ssh-agent-based user authentication. Windows users: set to 'pageant' for authenticating with Pageant or (actual) path to a cygwin "UNIX socket." Default: (none)

  • privateKey - mixed - Buffer or string that contains a private key for either key-based or hostbased user authentication (OpenSSH format). Default: (none)

  • passphrase - string - For an encrypted private key, this is the passphrase used to decrypt it. Default: (none)

  • localHostname - string - Along with localUsername and privateKey, set this to a non-empty string for hostbased user authentication. Default: (none)

  • localUsername - string - Along with localHostname and privateKey, set this to a non-empty string for hostbased user authentication. Default: (none)

  • tryKeyboard - boolean - Try keyboard-interactive user authentication if primary user authentication method fails. If you set this to true, you need to handle the keyboard-interactive event. Default: false

  • keepaliveInterval - integer - How often (in milliseconds) to send SSH-level keepalive packets to the server (in a similar way as OpenSSH's ServerAliveInterval config option). Set to 0 to disable. Default: 0

  • keepaliveCountMax - integer - How many consecutive, unanswered SSH-level keepalive packets that can be sent to the server before disconnection (similar to OpenSSH's ServerAliveCountMax config option). Default: 3

  • readyTimeout - integer - How long (in milliseconds) to wait for the SSH handshake to complete. Default: 20000

  • strictVendor - boolean - Performs a strict server vendor check before sending vendor-specific requests, etc. (e.g. check for OpenSSH server when using openssh_noMoreSessions()) Default: true

  • sock - ReadableStream - A ReadableStream to use for communicating with the server instead of creating and using a new TCP connection (useful for connection hopping).

  • agentForward - boolean - Set to true to use OpenSSH agent forwarding ([email protected]) for the life of the connection. agent must also be set to use this feature. Default: false

  • debug - function - Set this to a function that receives a single string argument to get detailed (local) debug information. Default: (none)

Authentication method priorities: Password -> Private Key -> Agent (-> keyboard-interactive if tryKeyboard is true) -> Hostbased -> None

• exec(< string >command[, < object >options], < function >callback) - boolean - Executes command on the server. Returns false if you should wait for the continue event before sending any more traffic. callback has 2 parameters: < Error >err, < Channel >stream. Valid options properties are:

  • env - object - An environment to use for the execution of the command.

  • pty - mixed - Set to true to allocate a pseudo-tty with defaults, or an object containing specific pseudo-tty settings (see 'Pseudo-TTY settings'). Setting up a pseudo-tty can be useful when working with remote processes that expect input from an actual terminal (e.g. sudo's password prompt).

  • x11 - mixed - Set to true to use defaults below, set to a number to specify a specific screen number, or an object with the following valid properties:

    • single - boolean - Allow just a single connection? Default: false

    • screen - number - Screen number to use Default: 0

• shell([[< mixed >window,] < object >options]< function >callback) - boolean - Starts an interactive shell session on the server, with an optional window object containing pseudo-tty settings (see 'Pseudo-TTY settings'). If window === false, then no pseudo-tty is allocated. options supports the x11 option as described in exec(). callback has 2 parameters: < Error >err, < Channel >stream. Returns false if you should wait for the continue event before sending any more traffic.

• forwardIn(< string >remoteAddr, < integer >remotePort, < function >callback) - boolean - Bind to remoteAddr on remotePort on the server and forward incoming TCP connections. callback has 2 parameters: < Error >err, < integer >port (port is the assigned port number if remotePort was 0). Returns false if you should wait for the continue event before sending any more traffic. Here are some special values for remoteAddr and their associated binding behaviors:

  • '' - Connections are to be accepted on all protocol families supported by the server.

  • '0.0.0.0' - Listen on all IPv4 addresses.

  • '::' - Listen on all IPv6 addresses.

  • 'localhost' - Listen on all protocol families supported by the server on loopback addresses only.

  • '127.0.0.1' and '::1' - Listen on the loopback interfaces for IPv4 and IPv6, respectively.

• unforwardIn(< string >remoteAddr, < integer >remotePort, < function >callback) - boolean - Unbind from remoteAddr on remotePort on the server and stop forwarding incoming TCP connections. Until callback is called, more connections may still come in. callback has 1 parameter: < Error >err. Returns false if you should wait for the continue event before sending any more traffic.

• forwardOut(< string >srcIP, < integer >srcPort, < string >dstIP, < integer >dstPort, < function >callback) - boolean - Open a connection with srcIP and srcPort as the originating address and port and dstIP and dstPort as the remote destination address and port. callback has 2 parameters: < Error >err, < Channel >stream. Returns false if you should wait for the continue event before sending any more traffic.

• sftp(< function >callback) - boolean - Starts an SFTP session. callback has 2 parameters: < Error >err, < SFTPStream >sftp. For methods available on sftp, see the SFTPStream client documentation (except read() and write() are used instead of readData() and writeData() respectively, for convenience). Returns false if you should wait for the continue event before sending any more traffic.

• subsys(< string >subsystem, < function >callback) - boolean - Invokes subsystem on the server. callback has 2 parameters: < Error >err, < Channel >stream. Returns false if you should wait for the continue event before sending any more traffic.

• end() - (void) - Disconnects the socket.

• openssh_noMoreSessions(< function >callback) - boolean - OpenSSH extension that sends a request to reject any new sessions (e.g. exec, shell, sftp, subsys) for this connection. callback has 1 parameter: < Error >err. Returns false if you should wait for the continue event before sending any more traffic.

• openssh_forwardInStreamLocal(< string >socketPath, < function >callback) - boolean - OpenSSH extension that binds to a UNIX domain socket at socketPath on the server and forwards incoming connections. callback has 1 parameter: < Error >err. Returns false if you should wait for the continue event before sending any more traffic.

• openssh_unforwardInStreamLocal(< string >socketPath, < function >callback) - boolean - OpenSSH extension that unbinds from a UNIX domain socket at socketPath on the server and stops forwarding incoming connections. callback has 1 parameter: < Error >err. Returns false if you should wait for the continue event before sending any more traffic.

• openssh_forwardOutStreamLocal(< string >socketPath, < function >callback) - boolean - OpenSSH extension that opens a connection to a UNIX domain socket at socketPath on the server. callback has 2 parameters: < Error >err, < Channel >stream. Returns false if you should wait for the continue event before sending any more traffic.

Server events

• connection(< Connection >client, < object >info) - A new client has connected. info contains the following properties:

  • ip - string - The remoteAddress of the connection.

  • header - object - Information about the client's header:

    • identRaw - string - The raw client identification string.

    • versions - object - Various version information:

      • protocol - string - The SSH protocol version (always 1.99 or 2.0).

      • software - string - The software name and version of the client.

    • comments - string - Any text that comes after the software name/version.

  Example: the identification string SSH-2.0-OpenSSH_6.6.1p1 Ubuntu-2ubuntu2 would be parsed as:

        { identRaw: 'SSH-2.0-OpenSSH_6.6.1p1 Ubuntu-2ubuntu2',
          version: {
            protocol: '2.0',
            software: 'OpenSSH_6.6.1p1'
          },
          comments: 'Ubuntu-2ubuntu2' }

Server methods

• (constructor)(< object >config[, < function >connectionListener]) - Creates and returns a new Server instance. Server instances also have the same methods/properties/events as net.Server. connectionListener if supplied, is added as a connection listener. Valid config properties:

  • privateKey - mixed - Buffer or string that contains the host private key (OpenSSH format). (Required) Default: (none)

  • passphrase - string - For an encrypted host private key, this is the passphrase used to decrypt it. Default: (none)

  • banner - string - A message that is sent to clients immediately upon connection, before handshaking begins. Default: (none)

  • ident - string - A custom server software name/version identifier. Default: 'ssh2js' + moduleVersion + 'srv'

  • highWaterMark - integer - This is the highWaterMark to use for the parser stream. Default: 32 * 1024

  • debug - function - Set this to a function that receives a single string argument to get detailed (local) debug information. Default: (none)

Connection events

• authentication(< AuthContext >ctx) - The client has requested authentication. ctx.username contains the client username, ctx.method contains the requested authentication method, and ctx.accept() and ctx.reject([< Array >authMethodsLeft[, < Boolean >isPartialSuccess]]) are used to accept or reject the authentication request respectively. abort is emitted if the client aborts the authentication request. Other properties/methods available on ctx depends on the ctx.method of authentication the client has requested:

  • password:

    • password - string - This is the password sent by the client.

  • publickey:

    • key - object - Contains information about the public key sent by the client:

      • algo - string - The name of the key algorithm (e.g. ssh-rsa).

      • data - Buffer - The actual key data.

    • sigAlgo - mixed - If the value is undefined, the client is only checking the validity of the key. If the value is a string, then this contains the signature algorithm that is passed to crypto.createVerify().

    • blob - mixed - If the value is undefined, the client is only checking the validity of the key. If the value is a Buffer, then this contains the data that is passed to verifier.update().

    • signature - mixed - If the value is undefined, the client is only checking the validity of the key. If the value is a Buffer, then this contains a signature that is passed to verifier.verify().

  • keyboard-interactive:

    • submethods - array - A list of preferred authentication "sub-methods" sent by the client. This may be used to determine what (if any) prompts to send to the client.

    • prompt(< array >prompts[, < string >title[, < string >instructions]], < function >callback) - boolean - Send prompts to the client. prompts is an array of { prompt: 'Prompt text', echo: true } objects (prompt being the prompt text and echo indicating whether the client's response to the prompt should be echoed to their display). callback is called with (err, responses), where responses is an array of string responses matching up to the prompts.

• ready() - Emitted when the client has been successfully authenticated.

• session(< function >accept, < function >reject) - Emitted when the client has requested a new session. Sessions are used to start interactive shells, execute commands, request X11 forwarding, etc. accept() returns a new Session instance. reject() Returns false if you should wait for the continue event before sending any more traffic.

• tcpip(< function >accept, < function >reject, < object >info) - Emitted when the client has requested an outbound (TCP) connection. accept() returns a new Channel instance representing the connection. reject() Returns false if you should wait for the continue event before sending any more traffic. info contains:

  • srcIP - string - Source IP address of outgoing connection.

  • srcPort - string - Source port of outgoing connection.

  • destIP - string - Destination IP address of outgoing connection.

  • destPort - string - Destination port of outgoing connection.

• openssh.streamlocal(< function >accept, < function >reject, < object >info) - Emitted when the client has requested a connection to a UNIX domain socket. accept() returns a new Channel instance representing the connection. reject() Returns false if you should wait for the continue event before sending any more traffic. info contains:

  • socketPath - string - Destination socket path of outgoing connection.

• request(< mixed >accept, < mixed >reject, < string >name, < object >info) - Emitted when the client has sent a global request for name (e.g. tcpip-forward or cancel-tcpip-forward). accept and reject are functions if the client requested a response. If bindPort === 0, you should pass the chosen port to accept() so that the client will know what port was bound. info contains additional details about the request:

  • tcpip-forward and cancel-tcpip-forward:

    • bindAddr - string - The IP address to start/stop binding to.

    • bindPort - integer - The port to start/stop binding to.

  • [email protected] and [email protected]:

    • socketPath - string - The socket path to start/stop binding to.

• rekey() - Emitted when the client has finished rekeying (either client or server initiated).

• continue() - Emitted when more requests/data can be sent to the client (after a Connection method returned false).

• error(< Error >err) - An error occurred.

• end() - The client socket disconnected.

• close(< boolean >hadError) - The client socket was closed. hadError is set to true if this was due to error.

Connection methods

• end() - boolean - Closes the client connection. Returns false if you should wait for the continue event before sending any more traffic.

• x11(< string >originAddr, < integer >originPort, < function >callback) - boolean - Alert the client of an incoming X11 client connection from originAddr on port originPort. callback has 2 parameters: < Error >err, < Channel >stream. Returns false if you should wait for the continue event before sending any more traffic.

• forwardOut(< string >boundAddr, < integer >boundPort, < string >remoteAddr, < integer >remotePort, < function >callback) - boolean - Alert the client of an incoming TCP connection on boundAddr on port boundPort from remoteAddr on port remotePort. callback has 2 parameters: < Error >err, < Channel >stream. Returns false if you should wait for the continue event before sending any more traffic.

• openssh_forwardOutStreamLocal(< string >socketPath, < function >callback) - boolean - Alert the client of an incoming UNIX domain socket connection on socketPath. callback has 2 parameters: < Error >err, < Channel >stream. Returns false if you should wait for the continue event before sending any more traffic.

• rekey([< function >callback]) - boolean - Initiates a rekeying with the client. If callback is supplied, it is added as a one-time handler for the rekey event. Returns false if you should wait for the continue event before sending any more traffic.

Session events

• pty(< mixed >accept, < mixed >reject, < object >info) - The client requested allocation of a pseudo-TTY for this session. accept and reject are functions if the client requested a response and return false if you should wait for the continue event before sending any more traffic. info has these properties:

  • cols - integer - The number of columns for the pseudo-TTY.

  • rows - integer - The number of rows for the pseudo-TTY.

  • width - integer - The width of the pseudo-TTY in pixels.

  • height - integer - The height of the pseudo-TTY in pixels.

  • modes - object - Contains the requested terminal modes of the pseudo-TTY keyed on the mode name with the value being the mode argument. (See the table at the end for valid names).

• window-change(< mixed >accept, < mixed >reject, < object >info) - The client reported a change in window dimensions during this session. accept and reject are functions if the client requested a response and return false if you should wait for the continue event before sending any more traffic. info has these properties:

  • cols - integer - The new number of columns for the client window.

  • rows - integer - The new number of rows for the client window.

  • width - integer - The new width of the client window in pixels.

  • height - integer - The new height of the client window in pixels.

• x11(< mixed >accept, < mixed >reject, < object >info) - The client requested X11 forwarding. accept and reject are functions if the client requested a response and return false if you should wait for the continue event before sending any more traffic. info has these properties:

  • single - boolean - true if only a single connection should be forwarded.

  • protocol - string - The name of the X11 authentication method used (e.g. MIT-MAGIC-COOKIE-1).

  • cookie - string - The X11 authentication cookie encoded in hexadecimal.

  • screen - integer - The screen number to forward X11 connections for.

• signal(< mixed >accept, < mixed >reject, < object >info) - The client has sent a signal. accept and reject are functions if the client requested a response and return false if you should wait for the continue event before sending any more traffic. info has these properties:

  • name - string - The signal name (e.g. SIGUSR1).

• auth-agent(< mixed >accept, < mixed >reject) - The client has requested incoming ssh-agent requests be forwarded to them. accept and reject are functions if the client requested a response and return false if you should wait for the continue event before sending any more traffic.

• shell(< mixed >accept, < mixed >reject) - The client has requested an interactive shell. accept and reject are functions if the client requested a response. accept() returns a Channel for the interactive shell. reject() Returns false if you should wait for the continue event before sending any more traffic.

• exec(< mixed >accept, < mixed >reject, < object >info) - The client has requested execution of a command string. accept and reject are functions if the client requested a response. accept() returns a Channel for the command execution. reject() Returns false if you should wait for the continue event before sending any more traffic. info has these properties:

  • command - string - The command line to be executed.

• sftp(< mixed >accept, < mixed >reject) - The client has requested the SFTP subsystem. accept and reject are functions if the client requested a response. accept() returns an SFTPStream in server mode (see the SFTPStream documentation for details). reject() Returns false if you should wait for the continue event before sending any more traffic. info has these properties:

• subsystem(< mixed >accept, < mixed >reject, < object >info) - The client has requested an arbitrary subsystem. accept and reject are functions if the client requested a response. accept() returns a Channel for the subsystem. reject() Returns false if you should wait for the continue event before sending any more traffic. info has these properties:

  • name - string - The name of the subsystem.

• close() - The session was closed.

Channel

This is a normal streams2 Duplex Stream, with the following changes:

• A boolean property allowHalfOpen exists and behaves similarly to the property of the same name for net.Socket. When the stream's end() is called, if allowHalfOpen is true, only EOF will be sent (the server can still send data if they have not already sent EOF). The default value for this property is true.

• A close event is emitted once the channel is completely closed on both the client and server.

• Client-only:

  • For exec():

    • An exit event may (the SSH2 spec says it is optional) be emitted when the process finishes. If the process finished normally, the process's return value is passed to the exit callback. If the process was interrupted by a signal, the following are passed to the exit callback: null, < string >signalName, < boolean >didCoreDump, < string >description.

    • If there was an exit event, the close event will be passed the same arguments for convenience.

  • For shell() and exec():

    • The readable side represents stdout and the writable side represents stdin.

    • A stderr property contains a Readable stream that represents output from stderr.

    • signal(< string >signalName) - boolean - Sends a POSIX signal to the current process on the server. Valid signal names are: 'ABRT', 'ALRM', 'FPE', 'HUP', 'ILL', 'INT', 'KILL', 'PIPE', 'QUIT', 'SEGV', 'TERM', 'USR1', and 'USR2'. Some server implementations may ignore this request if they do not support signals. Note: If you are trying to send SIGINT and you find signal() doesn't work, try writing '\x03' to the Channel stream instead. Returns false if you should wait for the continue event before sending any more traffic.

    • setWindow(< integer >rows, < integer >cols, < integer >height, < integer >width) - boolean - Lets the server know that the local terminal window has been resized. The meaning of these arguments are described in the 'Pseudo-TTY settings' section. Returns false if you should wait for the continue event before sending any more traffic.

• Server-only:

  • For exec-enabled channel instances there is an additional method available that may be called right before you close the channel. It has two different signatures:

    • exit(< integer >exitCode) - boolean - Sends an exit status code to the client. Returns false if you should wait for the continue event before sending any more traffic.

    • exit(< string >signalName[, < boolean >coreDumped[, < string >errorMsg]]) - boolean - Sends an exit status code to the client. Returns false if you should wait for the continue event before sending any more traffic.

  • For exec and shell-enabled channel instances, channel.stderr is a writable stream.

Pseudo-TTY settings

• rows - < integer > - Number of rows Default: 24

• cols - < integer > - Number of columns Default: 80

• height - < integer > - Height in pixels Default: 480

• width - < integer > - Width in pixels Default: 640

• term - < string > - The value to use for $TERM Default: 'vt100'

rows and cols override width and height when rows and cols are non-zero.

Pixel dimensions refer to the drawable area of the window.

Zero dimension parameters are ignored.

Terminal modes

Name           Description
------------------------------------------------------------
VINTR          Interrupt character; 255 if none.  Similarly
               for the other characters.  Not all of these
               characters are supported on all systems.
VQUIT          The quit character (sends SIGQUIT signal on
               POSIX systems).
VERASE         Erase the character to left of the cursor.
VKILL          Kill the current input line.
VEOF           End-of-file character (sends EOF from the
               terminal).
VEOL           End-of-line character in addition to
               carriage return and/or linefeed.
VEOL2          Additional end-of-line character.
VSTART         Continues paused output (normally
               control-Q).
VSTOP          Pauses output (normally control-S).
VSUSP          Suspends the current program.
VDSUSP         Another suspend character.
VREPRINT       Reprints the current input line.
VWERASE        Erases a word left of cursor.
VLNEXT         Enter the next character typed literally,
               even if it is a special character
VFLUSH         Character to flush output.
VSWTCH         Switch to a different shell layer.
VSTATUS        Prints system status line (load, command,
               pid, etc).
VDISCARD       Toggles the flushing of terminal output.
IGNPAR         The ignore parity flag.  The parameter
               SHOULD be 0 if this flag is FALSE,
               and 1 if it is TRUE.
PARMRK         Mark parity and framing errors.
INPCK          Enable checking of parity errors.
ISTRIP         Strip 8th bit off characters.
INLCR          Map NL into CR on input.
IGNCR          Ignore CR on input.
ICRNL          Map CR to NL on input.
IUCLC          Translate uppercase characters to
               lowercase.
IXON           Enable output flow control.
IXANY          Any char will restart after stop.
IXOFF          Enable input flow control.
IMAXBEL        Ring bell on input queue full.
ISIG           Enable signals INTR, QUIT, [D]SUSP.
ICANON         Canonicalize input lines.
XCASE          Enable input and output of uppercase
               characters by preceding their lowercase
               equivalents with "\".
ECHO           Enable echoing.
ECHOE          Visually erase chars.
ECHOK          Kill character discards current line.
ECHONL         Echo NL even if ECHO is off.
NOFLSH         Don't flush after interrupt.
TOSTOP         Stop background jobs from output.
IEXTEN         Enable extensions.
ECHOCTL        Echo control characters as ^(Char).
ECHOKE         Visual erase for line kill.
PENDIN         Retype pending input.
OPOST          Enable output processing.
OLCUC          Convert lowercase to uppercase.
ONLCR          Map NL to CR-NL.
OCRNL          Translate carriage return to newline
               (output).
ONOCR          Translate newline to carriage
               return-newline (output).
ONLRET         Newline performs a carriage return
               (output).
CS7            7 bit mode.
CS8            8 bit mode.
PARENB         Parity enable.
PARODD         Odd parity, else even.
TTY_OP_ISPEED  Specifies the input baud rate in
               bits per second.
TTY_OP_OSPEED  Specifies the output baud rate in
               bits per second.