webssh2/app/socket.js

328 lines
No EOL
10 KiB
JavaScript

// app/socket.js
'use strict'
const debug = require('debug')
const debugWebSSH2 = require('debug')('WebSSH2')
const SSH = require('ssh2').Client
let conn = null;
let stream = null;
/**
* Handles WebSocket connections for SSH
* @param {import('socket.io').Server} io - The Socket.IO server instance
* @param {Object} config - The configuration object
*/
module.exports = function (io, config) {
io.on('connection', (socket) => handleConnection(socket, config))
}
/**
* Handles a new WebSocket connection
* @param {import('socket.io').Socket} socket - The Socket.IO socket
* @param {Object} config - The configuration object
*/
function handleConnection(socket, config) {
let isConnectionClosed = false;
console.log(`SOCKET CONNECT: ${socket.id}`);
removeExistingListeners(socket)
setupInitialSocketListeners(socket, config)
/**
* Removes existing listeners to prevent duplicates
* @param {import('socket.io').Socket} socket - The Socket.IO socket
*/
function removeExistingListeners(socket) {
['authenticate', 'data', 'resize', 'disconnect', 'control'].forEach(event => {
socket.removeAllListeners(event)
})
}
/**
* Sets up initial socket event listeners
* @param {import('socket.io').Socket} socket - The Socket.IO socket
* @param {Object} config - The configuration object
*/
function setupInitialSocketListeners(socket, config) {
socket.on('authenticate', creds => handleAuthentication(socket, creds, config))
socket.on('disconnect', reason => handleDisconnect(socket, reason))
}
/**
* Handles authentication attempts
* @param {import('socket.io').Socket} socket - The Socket.IO socket
* @param {Credentials} creds - The credentials for authentication
* @param {Object} config - The configuration object
*/
function handleAuthentication(socket, creds, config) {
console.log(`SOCKET AUTHENTICATE: ${socket.id}`)
if (isValidCredentials(creds)) {
console.log(`SOCKET CREDENTIALS VALID: ${socket.id}`)
initializeConnection(socket, creds, config)
} else {
console.log(`SOCKET CREDENTIALS INVALID: ${socket.id}`)
socket.emit('auth_result', { success: false, message: 'Invalid credentials format' })
}
}
/**
* Initializes an SSH connection
* @param {import('socket.io').Socket} socket - The Socket.IO socket
* @param {Credentials} creds - The user credentials
* @param {Object} config - The configuration object
*/
function initializeConnection(socket, creds, config) {
if (conn) {
conn.end()
}
conn = new SSH()
conn.on('ready', () => {
console.log(`SSH CONNECTION READY: ${socket.id}`)
socket.emit('auth_result', { success: true })
socket.emit('allowreplay', config.options.allowReplay || false)
socket.emit('allowreauth', config.options.allowreauth || false)
setupSSHListeners(socket, creds)
initializeShell(socket, creds)
})
conn.on('error', err => {
console.log(`SSH CONNECTION ERROR: ${socket.id}`, err)
if (err.level === 'client-authentication') {
socket.emit('auth_result', { success: false, message: 'Authentication failed' })
} else {
handleError(socket, 'SSH CONNECTION ERROR', err)
}
})
conn.connect(getSSHConfig(creds, config))
}
/**
* Sets up SSH-specific event listeners
* @param {import('socket.io').Socket} socket - The Socket.IO socket
* @param {Credentials} creds - The user credentials
*/
function setupSSHListeners(socket, creds) {
conn.on('banner', data => handleBanner(socket, data))
conn.on('end', () => handleSSHEnd(socket))
conn.on('close', () => handleSSHClose(socket))
socket.on('data', data => handleData(socket, stream, data))
socket.on('resize', data => handleResize(stream, data))
socket.on('control', controlData => handleControl(socket, stream, creds, controlData, config))
}
/**
* Initializes the SSH shell
* @param {import('socket.io').Socket} socket - The Socket.IO socket
* @param {Credentials} creds - The user credentials
*/
function initializeShell(socket, creds) {
conn.shell(
{
term: creds.term,
cols: creds.cols,
rows: creds.rows
},
(err, str) => {
if (err) {
return handleError(socket, 'EXEC ERROR', err)
}
stream = str
stream.on('data', data => socket.emit('data', data.toString('utf-8')))
stream.on('close', (code, signal) => {
handleError(socket, 'STREAM CLOSE', {
message: code || signal ? `CODE: ${code} SIGNAL: ${signal}` : undefined
})
})
stream.stderr.on('data', data => console.log('STDERR: ' + data))
}
)
}
/**
* Handles the 'banner' event of the SSH connection
* @param {import('socket.io').Socket} socket - The Socket.IO socket
* @param {string} data - The banner data
*/
function handleBanner(socket, data) {
socket.emit('data', data.replace(/\r?\n/g, '\r\n'))
}
/**
* Handles the SSH connection end event
* @param {import('socket.io').Socket} socket - The Socket.IO socket
*/
function handleSSHEnd(socket) {
console.log(`SSH CONNECTION ENDED: ${socket.id}`)
handleConnectionClose(socket)
}
/**
* Handles the SSH connection close event
* @param {import('socket.io').Socket} socket - The Socket.IO socket
*/
function handleSSHClose(socket) {
console.log(`SSH CONNECTION CLOSED: ${socket.id}`)
handleConnectionClose(socket)
}
/**
* Handles the closure of the SSH connection
* @param {import('socket.io').Socket} socket - The Socket.IO socket
*/
function handleConnectionClose(socket) {
isConnectionClosed = true
if (stream) {
stream.end()
stream = null
}
if (conn) {
conn.end()
conn = null
}
socket.emit('connection_closed')
}
/**
* Handles socket disconnection
* @param {import('socket.io').Socket} socket - The Socket.IO socket
* @param {string} reason - The reason for disconnection
*/
function handleDisconnect(socket, reason) {
console.log(`SOCKET DISCONNECT: ${socket.id}, Reason: ${reason}`)
handleConnectionClose(socket)
}
/**
* Handles incoming data from the client
* @param {import('socket.io').Socket} socket - The Socket.IO socket
* @param {import('ssh2').Channel} stream - The SSH stream
* @param {string} data - The incoming data
*/
function handleData(socket, stream, data) {
if (stream && !isConnectionClosed) {
try {
stream.write(data)
} catch (error) {
console.log('Error writing to stream:', error.message)
handleConnectionClose(socket)
}
} else if (isConnectionClosed) {
console.log('Attempted to write to closed connection')
socket.emit('connection_closed')
}
}
/**
* Handles terminal resize events
* @param {import('ssh2').Channel} stream - The SSH stream
* @param {Object} data - The resize data
* @param {number} data.rows - The number of rows
* @param {number} data.cols - The number of columns
*/
function handleResize(stream, data) {
if (stream) {
stream.setWindow(data.rows, data.cols)
}
}
/**
* Handles control commands from the client
* @param {import('socket.io').Socket} socket - The Socket.IO socket
* @param {import('ssh2').Channel} stream - The SSH stream
* @param {Credentials} credentials - The user credentials
* @param {string} controlData - The control command
* @param {Object} config - The configuration object
*/
function handleControl(socket, stream, credentials, controlData, config) {
console.log(`Received control data: ${controlData}`);
if (controlData === 'replayCredentials' && stream && credentials) {
replayCredentials(socket, stream, credentials, config);
} else if (controlData === 'reauth' && config.options.allowreauth) {
handleReauth(socket);
}
}
/**
* Replays the user credentials to the SSH stream
* @param {import('socket.io').Socket} socket - The Socket.IO socket
* @param {import('ssh2').Channel} stream - The SSH stream
* @param {Credentials} credentials - The user credentials
* @param {Object} config - The configuration object
*/
function replayCredentials(socket, stream, credentials, config) {
let allowReplay = config.options.allowReplay || false;
if (allowReplay) {
console.log(`Replaying credentials for ${socket.id}`);
stream.write(credentials.password + '\n');
} else {
console.log(`Credential replay not allowed for ${socket.id}`);
}
}
/**
* Handles reauthentication request
* @param {import('socket.io').Socket} socket - The Socket.IO socket
*/
function handleReauth(socket) {
console.log(`Reauthentication requested for ${socket.id}`);
handleConnectionClose(socket);
socket.emit('reauth');
}
/**
* Handles SSH errors
* @param {import('socket.io').Socket} socket - The Socket.IO socket
* @param {string} context - The context where the error occurred
* @param {Error} [err] - The error object
*/
function handleError(socket, context, err) {
const errorMessage = err ? `: ${err.message}` : ''
console.log(`WebSSH2 error: ${context}${errorMessage}`)
socket.emit('ssherror', `SSH ${context}${errorMessage}`)
handleConnectionClose(socket)
}
/**
* Validates the provided credentials
* @param {Credentials} credentials - The credentials to validate
* @returns {boolean} Whether the credentials are valid
*/
function isValidCredentials(credentials) {
// Basic format validation
return credentials &&
typeof credentials.username === 'string' &&
typeof credentials.password === 'string' &&
typeof credentials.host === 'string' &&
typeof credentials.port === 'number'
}
/**
* Generates the SSH configuration object
* @param {Credentials} credentials - The user credentials
* @param {Object} config - The configuration object
* @returns {import('ssh2').ConnectConfig} The SSH configuration object
*/
function getSSHConfig(credentials, config) {
return {
host: credentials.host,
port: credentials.port,
username: credentials.username,
password: credentials.password,
tryKeyboard: true,
algorithms: credentials.algorithms,
readyTimeout: credentials.readyTimeout,
keepaliveInterval: credentials.keepaliveInterval,
keepaliveCountMax: credentials.keepaliveCountMax,
debug: debug('ssh2')
}
}
}