/** * @description Meshcentral web relay server * @author Ylian Saint-Hilaire * @copyright Intel Corporation 2018-2022 * @license Apache-2.0 * @version v0.0.1 */ /*jslint node: true */ /*jshint node: true */ /*jshint strict:false */ /*jshint -W097 */ /*jshint esversion: 6 */ "use strict"; // Construct a HTTP redirection web server object module.exports.CreateWebRelayServer = function (parent, db, args, certificates, func) { var obj = {}; obj.parent = parent; obj.db = db; obj.express = require('express'); obj.expressWs = null; obj.tlsServer = null; obj.net = require('net'); obj.app = obj.express(); if (args.compression !== false) { obj.app.use(require('compression')()); } obj.app.disable('x-powered-by'); obj.webRelayServer = null; obj.port = 0; obj.cleanupTimer = null; var relaySessions = {} // RelayID --> Web Mutli-Tunnel const constants = (require('crypto').constants ? require('crypto').constants : require('constants')); // require('constants') is deprecated in Node 11.10, use require('crypto').constants instead. var tlsSessionStore = {}; // Store TLS session information for quick resume. var tlsSessionStoreCount = 0; // Number of cached TLS session information in store. function serverStart() { // Setup CrowdSec bouncer middleware if needed if (parent.crowdsecMiddleware != null) { obj.app.use(parent.crowdsecMiddleware); } if (args.trustedproxy) { // Reverse proxy should add the "X-Forwarded-*" headers try { obj.app.set('trust proxy', args.trustedproxy); } catch (ex) { // If there is an error, try to resolve the string if ((args.trustedproxy.length == 1) && (typeof args.trustedproxy[0] == 'string')) { require('dns').lookup(args.trustedproxy[0], function (err, address, family) { if (err == null) { obj.app.set('trust proxy', address); args.trustedproxy = [address]; } }); } } } else if (typeof args.tlsoffload == 'object') { // Reverse proxy should add the "X-Forwarded-*" headers try { obj.app.set('trust proxy', args.tlsoffload); } catch (ex) { // If there is an error, try to resolve the string if ((Array.isArray(args.tlsoffload)) && (args.tlsoffload.length == 1) && (typeof args.tlsoffload[0] == 'string')) { require('dns').lookup(args.tlsoffload[0], function (err, address, family) { if (err == null) { obj.app.set('trust proxy', address); args.tlsoffload = [address]; } }); } } } // Setup a keygrip instance with higher default security, default hash is SHA1, we want to bump that up with SHA384 // If multiple instances of this server are behind a load-balancer, this secret must be the same for all instances // If args.sessionkey is a string, use it as a single key, but args.sessionkey can also be used as an array of keys. const keygrip = require('keygrip')((typeof args.sessionkey == 'string') ? [args.sessionkey] : args.sessionkey, 'sha384', 'base64'); // Setup cookie session const sessionOptions = { name: 'xid', // Recommended security practice to not use the default cookie name httpOnly: true, keys: keygrip, secure: (args.tlsoffload == null), // Use this cookie only over TLS (Check this: https://expressjs.com/en/guide/behind-proxies.html) sameSite: (args.sessionsamesite ? args.sessionsamesite : 'lax') } if (args.sessiontime != null) { sessionOptions.maxAge = (args.sessiontime * 60000); } // sessiontime is minutes obj.app.use(require('cookie-session')(sessionOptions)); // Add HTTP security headers to all responses obj.app.use(function (req, res, next) { parent.debug('webrelay', req.url); res.removeHeader('X-Powered-By'); res.set({ 'strict-transport-security': 'max-age=60000; includeSubDomains', 'Referrer-Policy': 'no-referrer', 'x-frame-options': 'SAMEORIGIN', 'X-XSS-Protection': '1; mode=block', 'X-Content-Type-Options': 'nosniff', 'Content-Security-Policy': "default-src 'self'; style-src 'self' 'unsafe-inline';" }); // Set the real IP address of the request // If a trusted reverse-proxy is sending us the remote IP address, use it. var ipex = '0.0.0.0', xforwardedhost = req.headers.host; if (typeof req.connection.remoteAddress == 'string') { ipex = (req.connection.remoteAddress.startsWith('::ffff:')) ? req.connection.remoteAddress.substring(7) : req.connection.remoteAddress; } if ( (args.trustedproxy === true) || (args.tlsoffload === true) || ((typeof args.trustedproxy == 'object') && (isIPMatch(ipex, args.trustedproxy))) || ((typeof args.tlsoffload == 'object') && (isIPMatch(ipex, args.tlsoffload))) ) { // Get client IP if (req.headers['cf-connecting-ip']) { // Use CloudFlare IP address if present req.clientIp = req.headers['cf-connecting-ip'].split(',')[0].trim(); } else if (req.headers['x-forwarded-for']) { req.clientIp = req.headers['x-forwarded-for'].split(',')[0].trim(); } else if (req.headers['x-real-ip']) { req.clientIp = req.headers['x-real-ip'].split(',')[0].trim(); } else { req.clientIp = ipex; } // If there is a port number, remove it. This will only work for IPv4, but nice for people that have a bad reverse proxy config. const clientIpSplit = req.clientIp.split(':'); if (clientIpSplit.length == 2) { req.clientIp = clientIpSplit[0]; } // Get server host if (req.headers['x-forwarded-host']) { xforwardedhost = req.headers['x-forwarded-host'].split(',')[0]; } // If multiple hosts are specified with a comma, take the first one. } else { req.clientIp = ipex; } // If this is a session start or a websocket, have the application handle this if ((req.headers.upgrade == 'websocket') || (req.url.startsWith('/control-redirect.ashx?n='))) { return next(); } else { // If this is a normal request (GET, POST, etc) handle it here var webSessionId = null; if ((req.session.userid != null) && (req.session.x != null)) { webSessionId = req.session.userid + '/' + req.session.x; } else if (req.session.z != null) { webSessionId = req.session.z; } if ((webSessionId != null) && (parent.webserver.destroyedSessions[webSessionId] == null)) { var relaySession = relaySessions[webSessionId]; if (relaySession != null) { // The web relay session is valid, use it relaySession.handleRequest(req, res); } else { // No web relay ession with this relay identifier, close the HTTP request. res.end(); } } else { // The user is not logged in or does not have a relay identifier, close the HTTP request. res.end(); } } }); // Start the server, only after users and meshes are loaded from the database. if (args.tlsoffload) { // Setup the HTTP server without TLS obj.expressWs = require('express-ws')(obj.app, null, { wsOptions: { perMessageDeflate: (args.wscompression === true) } }); } else { // Setup the HTTP server with TLS, use only TLS 1.2 and higher with perfect forward secrecy (PFS). const tlsOptions = { cert: certificates.web.cert, key: certificates.web.key, ca: certificates.web.ca, rejectUnauthorized: true, ciphers: "HIGH:TLS_AES_256_GCM_SHA384:TLS_AES_128_GCM_SHA256:TLS_AES_128_CCM_8_SHA256:TLS_AES_128_CCM_SHA256:TLS_CHACHA20_POLY1305_SHA256", secureOptions: constants.SSL_OP_NO_SSLv2 | constants.SSL_OP_NO_SSLv3 | constants.SSL_OP_NO_COMPRESSION | constants.SSL_OP_CIPHER_SERVER_PREFERENCE | constants.SSL_OP_NO_TLSv1 | constants.SSL_OP_NO_TLSv1_1 }; obj.tlsServer = require('https').createServer(tlsOptions, obj.app); obj.tlsServer.on('secureConnection', function () { /*console.log('tlsServer secureConnection');*/ }); obj.tlsServer.on('error', function (err) { console.log('tlsServer error', err); }); obj.tlsServer.on('newSession', function (id, data, cb) { if (tlsSessionStoreCount > 1000) { tlsSessionStoreCount = 0; tlsSessionStore = {}; } tlsSessionStore[id.toString('hex')] = data; tlsSessionStoreCount++; cb(); }); obj.tlsServer.on('resumeSession', function (id, cb) { cb(null, tlsSessionStore[id.toString('hex')] || null); }); obj.expressWs = require('express-ws')(obj.app, obj.tlsServer, { wsOptions: { perMessageDeflate: (args.wscompression === true) } }); } // Handle incoming web socket calls obj.app.ws('/*', function (ws, req) { var webSessionId = null; if ((req.session.userid != null) && (req.session.x != null)) { webSessionId = req.session.userid + '/' + req.session.x; } else if (req.session.z != null) { webSessionId = req.session.z; } if ((webSessionId != null) && (parent.webserver.destroyedSessions[webSessionId] == null)) { var relaySession = relaySessions[webSessionId]; if (relaySession != null) { // The multi-tunnel session is valid, use it relaySession.handleWebSocket(ws, req); } else { // No multi-tunnel session with this relay identifier, close the websocket. ws.close(); } } else { // The user is not logged in or does not have a relay identifier, close the websocket. ws.close(); } }); // This is the magic URL that will setup the relay session obj.app.get('/control-redirect.ashx', function (req, res) { res.set({ 'Cache-Control': 'no-store' }); parent.debug('webrelay', 'webRelaySetup'); // Decode the relay cookie if (req.query.c == null) { res.sendStatus(404); return; } // Decode and check if this relay cookie is valid var userid, domainid, domain, nodeid, addr, port, appid, webSessionId, expire; const urlCookie = obj.parent.decodeCookie(req.query.c, parent.loginCookieEncryptionKey, 32); // Allow cookies up to 32 minutes old. The web page will renew this cookie every 30 minutes. if (urlCookie == null) { res.sendStatus(404); return; } // Decode the incomign cookie if ((urlCookie.ruserid != null) && (urlCookie.x != null)) { if (parent.webserver.destroyedSessions[urlCookie.ruserid + '/' + urlCookie.x] != null) { res.sendStatus(404); return; } // This is a standard user, figure out what our web relay will be. if (req.session.x != urlCookie.x) { req.session.x = urlCookie.x; } // Set the sessionid if missing if (req.session.userid != urlCookie.ruserid) { req.session.userid = urlCookie.ruserid; } // Set the session userid if missing if (req.session.z) { delete req.session.z; } // Clear the web relay guest session userid = req.session.userid; domainid = userid.split('/')[1]; domain = parent.config.domains[domainid]; nodeid = ((req.query.relayid != null) ? req.query.relayid : req.query.n); addr = (req.query.addr != null) ? req.query.addr : '127.0.0.1'; port = parseInt(req.query.p); appid = parseInt(req.query.appid); webSessionId = req.session.userid + '/' + req.session.x; // Check that all the required arguments are present if ((req.session.userid == null) || (req.session.x == null) || (req.query.n == null) || (req.query.p == null) || (parent.webserver.destroyedSessions[webSessionId] != null) || ((req.query.appid != 1) && (req.query.appid != 2))) { res.redirect('/'); return; } } else if (urlCookie.r == 8) { // This is a guest user, figure out what our web relay will be. userid = urlCookie.userid; domainid = userid.split('/')[1]; domain = parent.config.domains[domainid]; nodeid = urlCookie.nid; addr = (urlCookie.addr != null) ? urlCookie.addr : '127.0.0.1'; port = urlCookie.port; appid = (urlCookie.p == 16) ? 2 : 1; // appid: 1 = HTTP, 2 = HTTPS webSessionId = userid + '/' + urlCookie.pid; if (req.session.x) { delete req.session.x; } // Clear the web relay sessionid if (req.session.userid) { delete req.session.userid; } // Clear the web relay userid if (req.session.z != webSessionId) { req.session.z = webSessionId; } // Set the web relay guest session expire = urlCookie.expire; if ((expire != null) && (expire <= Date.now())) { parent.debug('webrelay', 'expired link'); res.sendStatus(404); return; } } // No session identifier was setup, exit now if (webSessionId == null) { res.sendStatus(404); return; } // Check to see if we already have a multi-relay session that matches exactly this device and port for this user const xrelaySession = relaySessions[webSessionId]; if ((xrelaySession != null) && (xrelaySession.domain.id == domain.id) && (xrelaySession.userid == userid) && (xrelaySession.nodeid == nodeid) && (xrelaySession.addr == addr) && (xrelaySession.port == port) && (xrelaySession.appid == appid)) { // We found an exact match, we are all setup already, redirect to root res.redirect('/'); return; } // Check that the user has rights to access this device parent.webserver.GetNodeWithRights(domain, userid, nodeid, function (node, rights, visible) { // If there is no remote control rights, reject this web relay if ((rights & 8) == 0) { res.sendStatus(404); return; } // There is a relay session, but it's not correct, close it. if (xrelaySession != null) { xrelaySession.close(); delete relaySessions[webSessionId]; } // Create a web relay session const relaySession = require('./apprelays.js').CreateWebRelaySession(obj, db, req, args, domain, userid, nodeid, addr, port, appid, webSessionId, expire); relaySession.onclose = function (sessionId) { // Remove the relay session delete relaySessions[sessionId]; // If there are not more relay sessions, clear the cleanup timer if ((Object.keys(relaySessions).length == 0) && (obj.cleanupTimer != null)) { clearInterval(obj.cleanupTimer); obj.cleanupTimer = null; } } // Set the multi-tunnel session relaySessions[webSessionId] = relaySession; // Setup the cleanup timer if needed if (obj.cleanupTimer == null) { obj.cleanupTimer = setInterval(checkTimeout, 10000); } // Redirect to root res.redirect('/'); }); }); } // Check that everything is cleaned up function checkTimeout() { for (var i in relaySessions) { relaySessions[i].checkTimeout(); } } // Find a free port starting with the specified one and going up. function CheckListenPort(port, addr, func) { var s = obj.net.createServer(function (socket) { }); obj.webRelayServer = s.listen(port, addr, function () { s.close(function () { if (func) { func(port, addr); } }); }).on("error", function (err) { if (args.exactports) { console.error("ERROR: MeshCentral HTTP relay server port " + port + " not available."); process.exit(); } else { if (port < 65535) { CheckListenPort(port + 1, addr, func); } else { if (func) { func(0); } } } }); } // Start the ExpressJS web server, if the port is busy try the next one. function StartWebRelayServer(port, addr) { if (port == 0 || port == 65535) { return; } if (obj.tlsServer != null) { if (args.lanonly == true) { obj.tcpServer = obj.tlsServer.listen(port, addr, function () { console.log('MeshCentral HTTPS relay server running on port ' + port + ((typeof args.relayaliasport == 'number') ? (', alias port ' + args.relayaliasport) : '') + '.'); }); } else { obj.tcpServer = obj.tlsServer.listen(port, addr, function () { console.log('MeshCentral HTTPS relay server running on ' + certificates.CommonName + ':' + port + ((typeof args.relayaliasport == 'number') ? (', alias port ' + args.relayaliasport) : '') + '.'); }); obj.parent.updateServerState('servername', certificates.CommonName); } if (obj.parent.authlog) { obj.parent.authLog('https', 'Web relay server listening on ' + ((addr != null) ? addr : '0.0.0.0') + ' port ' + port + '.'); } obj.parent.updateServerState('https-relay-port', port); if (typeof args.relayaliasport == 'number') { obj.parent.updateServerState('https-relay-aliasport', args.relayaliasport); } } else { obj.tcpServer = obj.app.listen(port, addr, function () { console.log('MeshCentral HTTP relay server running on port ' + port + ((typeof args.relayaliasport == 'number') ? (', alias port ' + args.relayaliasport) : '') + '.'); }); obj.parent.updateServerState('http-relay-port', port); if (typeof args.relayaliasport == 'number') { obj.parent.updateServerState('http-relay-aliasport', args.relayaliasport); } } obj.port = port; } function getRandomPassword() { return Buffer.from(require('crypto').randomBytes(9), 'binary').toString('base64').split('/').join('@'); } // Perform a IP match against a list function isIPMatch(ip, matchList) { const ipcheck = require('ipcheck'); for (var i in matchList) { if (ipcheck.match(ip, matchList[i]) == true) return true; } return false; } // Start up the web relay server serverStart(); CheckListenPort(args.relayport, args.relayportbind, StartWebRelayServer); return obj; };