sync/src/io/ioserver.js
2026-05-04 16:07:59 +02:00

572 lines
19 KiB
JavaScript

import sio from 'socket.io';
import db from '../database';
import User from '../user';
import Server from '../server';
import Config from '../config';
const cookieParser = require("cookie-parser")(Config.get("http.cookie-secret"));
import typecheck from 'json-typecheck';
import { isTorExit } from '../tor';
import session from '../session';
import { verifyIPSessionCookie } from '../web/middleware/ipsessioncookie';
import Promise from 'bluebird';
const verifySession = Promise.promisify(session.verifySession);
const getAliases = Promise.promisify(db.getAliases);
import crypto from 'crypto';
const botDB = require('../database/bots');
const botSocketRegistry = require('../bot-socket-registry');
import { CachingGlobalBanlist } from './globalban';
import proxyaddr from 'proxy-addr';
import { Counter, Gauge } from 'prom-client';
import { TokenBucket } from '../util/token-bucket';
import http from 'http';
const LOGGER = require('@calzoneman/jsli')('ioserver');
const rateLimitExceeded = new Counter({
name: 'cytube_socketio_rate_limited_total',
help: 'Number of socket.io connections rejected due to exceeding rate limit'
});
const connLimitExceeded = new Counter({
name: 'cytube_socketio_conn_limited_total',
help: 'Number of socket.io connections rejected due to exceeding conn limit'
});
const authFailureCount = new Counter({
name: 'cytube_socketio_auth_error_total',
help: 'Number of failed authentications from session middleware'
});
class IOServer {
constructor(options = {
proxyTrustFn: proxyaddr.compile('127.0.0.1')
}) {
({
proxyTrustFn: this.proxyTrustFn
} = options);
this.ipThrottle = new Map();
this.ipCount = new Map();
}
// Map proxied sockets to the real IP address via X-Forwarded-For
// If the resulting address is a known Tor exit, flag it as such
ipProxyMiddleware(socket, next) {
if (!socket.context) socket.context = {};
try {
socket.handshake.connection = {
remoteAddress: socket.handshake.address
};
socket.context.ipAddress = proxyaddr(
socket.handshake,
this.proxyTrustFn
);
if (!socket.context.ipAddress) {
throw new Error(
`Assertion failed: unexpected IP ${socket.context.ipAddress}`
);
}
} catch (error) {
LOGGER.warn('Rejecting socket - proxyaddr failed: %s', error);
next(new Error('Could not determine IP address'));
return;
}
if (isTorExit(socket.context.ipAddress)) {
socket.context.torConnection = true;
}
next();
}
// Reject global banned IP addresses
ipBanMiddleware(socket, next) {
if (isIPGlobalBanned(socket.context.ipAddress)) {
LOGGER.info('Rejecting %s - banned',
socket.context.ipAddress);
next(new Error('You are banned from the server'));
return;
}
next();
}
// Rate limit connection attempts by IP address
ipThrottleMiddleware(socket, next) {
if (!this.ipThrottle.has(socket.context.ipAddress)) {
this.ipThrottle.set(socket.context.ipAddress, new TokenBucket(5, 0.1));
}
const bucket = this.ipThrottle.get(socket.context.ipAddress);
if (bucket.throttle()) {
rateLimitExceeded.inc(1);
LOGGER.info('Rejecting %s - exceeded connection rate limit',
socket.context.ipAddress);
next(new Error('Rate limit exceeded'));
return;
}
next();
}
checkIPLimit(socket) {
const ip = socket.context.ipAddress;
const count = this.ipCount.get(ip) || 0;
if (count >= Config.get('io.ip-connection-limit')) {
connLimitExceeded.inc(1);
LOGGER.info(
'Rejecting %s - exceeded connection count limit',
ip
);
socket.emit('kick', {
reason: 'Too many connections from your IP address'
});
socket.disconnect(true);
return false;
}
this.ipCount.set(ip, count + 1);
socket.once('disconnect', () => {
const newCount = (this.ipCount.get(ip) || 1) - 1;
if (newCount === 0) {
this.ipCount.delete(ip);
} else {
this.ipCount.set(ip, newCount);
}
});
return true;
}
// Parse cookies
cookieParsingMiddleware(socket, next) {
const req = socket.handshake;
if (req.headers.cookie) {
cookieParser(req, null, () => next());
} else {
req.cookies = {};
req.signedCookies = {};
next();
}
}
// Determine session age from ip-session cookie
// (Used for restricting chat)
ipSessionCookieMiddleware(socket, next) {
const cookie = socket.handshake.signedCookies['ip-session'];
if (!cookie) {
socket.context.ipSessionFirstSeen = new Date();
next();
return;
}
const sessionMatch = verifyIPSessionCookie(socket.context.ipAddress, cookie);
if (sessionMatch) {
socket.context.ipSessionFirstSeen = sessionMatch.date;
} else {
socket.context.ipSessionFirstSeen = new Date();
}
next();
}
// Match login cookie against the DB, look up aliases
// Also handles bot token auth via socket.handshake.auth.token
authUserMiddleware(socket, next) {
socket.context.aliases = [];
const promises = [];
const botToken = socket.handshake.auth && socket.handshake.auth.token;
if (botToken && typeof botToken === 'string' && botToken.startsWith('cbt_')) {
const tokenHash = crypto.createHash('sha256').update(botToken).digest('hex');
promises.push(
botDB.getBotByTokenHash(tokenHash).then(bot => {
if (bot) {
socket.context.user = {
name: bot.name,
global_rank: bot.rank,
time: Date.now(),
profile: { image: '', text: '' },
isBot: true,
botId: bot.id,
botChannelName: bot.channel_name
};
botSocketRegistry.register(bot.id, socket);
botDB.updateLastConnected(bot.id).catch(err => {
LOGGER.warn('Failed to update bot last_connected: %s', err);
});
} else {
LOGGER.warn('Bot token auth failed for %s - invalid or revoked',
socket.context.ipAddress);
}
}).catch(err => {
LOGGER.warn('Bot token lookup error for %s: %s',
socket.context.ipAddress, err);
})
);
} else {
const auth = socket.handshake.signedCookies.auth;
if (auth) {
promises.push(verifySession(auth).then(user => {
socket.context.user = Object.assign({}, user);
}).catch(_error => {
authFailureCount.inc(1);
LOGGER.warn('Unable to verify session for %s - ignoring auth',
socket.context.ipAddress);
}));
}
}
promises.push(getAliases(socket.context.ipAddress).then(aliases => {
socket.context.aliases = aliases;
}).catch(_error => {
LOGGER.warn('Unable to load aliases for %s',
socket.context.ipAddress);
}));
Promise.all(promises).then(() => next());
}
handleConnection(socket) {
if (!this.checkIPLimit(socket)) {
return;
}
patchTypecheckedFunctions(socket);
patchSocketMetrics(socket);
this.setRateLimiter(socket);
emitMetrics(socket);
LOGGER.info('Accepted socket from %s', socket.context.ipAddress);
socket.once('disconnect', (reason, reasonDetail) => {
LOGGER.info(
'%s disconnected (%s%s)',
socket.context.ipAddress,
reason,
reasonDetail ? ` - ${reasonDetail}` : ''
);
});
const user = new User(socket, socket.context.ipAddress, socket.context.user);
if (socket.context.user && !socket.context.user.isBot) {
db.recordVisit(socket.context.ipAddress, user.getName());
}
const announcement = Server.getServer().announcement;
if (announcement !== null) {
socket.emit('announcement', announcement);
}
}
setRateLimiter(socket) {
const refillRate = () => Config.get('io.throttle.in-rate-limit');
const capacity = () => Config.get('io.throttle.bucket-capacity');
socket._inRateLimit = new TokenBucket(capacity, refillRate);
socket.on('cytube:count-event', () => {
if (socket._inRateLimit.throttle()) {
LOGGER.warn(
'Kicking client %s: exceeded in-rate-limit of %d',
socket.context.ipAddress,
refillRate()
);
socket.emit('kick', { reason: 'Rate limit exceeded' });
socket.disconnect();
}
});
}
initSocketIO() {
const io = this.io = sio.instance = sio();
io.use(this.ipProxyMiddleware.bind(this));
io.use(this.ipBanMiddleware.bind(this));
io.use(this.ipThrottleMiddleware.bind(this));
io.use(this.cookieParsingMiddleware.bind(this));
io.use(this.ipSessionCookieMiddleware.bind(this));
io.use(this.authUserMiddleware.bind(this));
io.on('connection', this.handleConnection.bind(this));
}
bindTo(servers) {
if (!this.io) {
throw new Error('Cannot bind: socket.io has not been initialized yet');
}
const engineOpts = {
/*
* Set ping timeout to 2 minutes to avoid spurious reconnects
* during transient network issues. The default of 20 seconds
* is too aggressive.
*
* https://github.com/calzoneman/sync/issues/780
*/
pingTimeout: 120000,
/*
* Per `ws` docs: "Note that Node.js has a variety of issues with
* high-performance compression, where increased concurrency,
* especially on Linux, can lead to catastrophic memory
* fragmentation and slow performance."
*
* CyTube's frames are ordinarily quite small, so there's not much
* point in compressing them.
*/
perMessageDeflate: false,
httpCompression: false,
maxHttpBufferSize: 1 << 20,
/*
* Enable legacy support for socket.io v2 clients (e.g., bots)
*/
allowEIO3: true,
cors: {
origin: getCorsAllowCallback(),
credentials: true // enable cookies for auth
}
};
servers.forEach(server => {
this.io.attach(server, engineOpts);
});
}
}
const incomingEventCount = new Counter({
name: 'cytube_socketio_incoming_events_total',
help: 'Number of received socket.io events from clients'
});
const outgoingPacketCount = new Counter({
name: 'cytube_socketio_outgoing_packets_total',
help: 'Number of outgoing socket.io packets to clients'
});
function patchSocketMetrics(sock) {
const emit = require('events').EventEmitter.prototype.emit;
sock.onAny(() => {
incomingEventCount.inc(1);
emit.call(sock, 'cytube:count-event');
});
let packet = sock.packet;
sock.packet = function patchedPacket() {
packet.apply(this, arguments);
outgoingPacketCount.inc(1);
}.bind(sock);
}
/* TODO: remove this crap */
/* Addendum 2021-08-14: socket.io v4 supports middleware, maybe move type validation to that */
function patchTypecheckedFunctions(sock) {
sock.typecheckedOn = function typecheckedOn(msg, template, cb) {
this.on(msg, (data, ack) => {
typecheck(data, template, (err, data) => {
if (err) {
this.emit("errorMsg", {
msg: "Unexpected error for message " + msg + ": " + err.message
});
} else {
cb(data, ack);
}
});
});
}.bind(sock);
sock.typecheckedOnce = function typecheckedOnce(msg, template, cb) {
this.once(msg, data => {
typecheck(data, template, (err, data) => {
if (err) {
this.emit("errorMsg", {
msg: "Unexpected error for message " + msg + ": " + err.message
});
} else {
cb(data);
}
});
});
}.bind(sock);
}
let globalIPBanlist = null;
function isIPGlobalBanned(ip) {
if (globalIPBanlist === null) {
globalIPBanlist = new CachingGlobalBanlist(db.getGlobalBanDB());
globalIPBanlist.refreshCache();
globalIPBanlist.startCacheTimer(60 * 1000);
}
return globalIPBanlist.isIPGlobalBanned(ip);
}
const promSocketCount = new Gauge({
name: 'cytube_sockets_num_connected',
help: 'Gauge of connected socket.io clients',
labelNames: ['transport']
});
const promSocketAccept = new Counter({
name: 'cytube_sockets_accepts_total',
help: 'Counter for number of connections accepted. Excludes rejected connections.'
});
const promSocketDisconnect = new Counter({
name: 'cytube_sockets_disconnects_total',
help: 'Counter for number of connections disconnected.'
});
const promSocketReconnect = new Counter({
name: 'cytube_sockets_reconnects_total',
help: 'Counter for number of reconnects detected.'
});
function emitMetrics(sock) {
try {
let closed = false;
let transportName = sock.conn.transport.name;
promSocketCount.inc({ transport: transportName });
promSocketAccept.inc(1);
sock.conn.on('upgrade', () => {
try {
let newTransport = sock.conn.transport.name;
// Sanity check
if (!closed && newTransport !== transportName) {
promSocketCount.dec({ transport: transportName });
transportName = newTransport;
promSocketCount.inc({ transport: transportName });
}
} catch (error) {
LOGGER.error('Error emitting transport upgrade metrics for socket (ip=%s): %s',
sock.context.ipAddress, error.stack);
}
});
sock.once('disconnect', () => {
try {
closed = true;
promSocketCount.dec({ transport: transportName });
promSocketDisconnect.inc(1);
} catch (error) {
LOGGER.error('Error emitting disconnect metrics for socket (ip=%s): %s',
sock.context.ipAddress, error.stack);
}
});
sock.once('reportReconnect', () => {
try {
promSocketReconnect.inc(1, new Date());
} catch (error) {
LOGGER.error('Error emitting reconnect metrics for socket (ip=%s): %s',
sock.context.ipAddress, error.stack);
}
});
} catch (error) {
LOGGER.error('Error emitting metrics for socket (ip=%s): %s',
sock.context.ipAddress, error.stack);
}
}
let instance = null;
module.exports = {
init: function (srv, webConfig) {
if (instance !== null) {
throw new Error('ioserver.init: already initialized');
}
const ioServer = instance = new IOServer({
proxyTrustFn: proxyaddr.compile(webConfig.getTrustedProxies())
});
ioServer.initSocketIO();
const uniqueListenAddresses = new Set();
const servers = [];
Config.get("listen").forEach(function (bind) {
if (!bind.io) {
return;
}
const id = bind.ip + ":" + bind.port;
if (uniqueListenAddresses.has(id)) {
LOGGER.warn("Ignoring duplicate listen address %s", id);
return;
}
if (srv.servers.hasOwnProperty(id)) {
servers.push(srv.servers[id]);
} else {
const server = http.createServer().listen(bind.port, bind.ip);
servers.push(server);
server.on("error", error => {
if (error.code === "EADDRINUSE") {
LOGGER.fatal(
"Could not bind %s: address already in use. Check " +
"whether another application has already bound this " +
"port, or whether another instance of this server " +
"is running.",
id
);
process.exit(1);
}
});
}
uniqueListenAddresses.add(id);
});
ioServer.bindTo(servers);
},
IOServer: IOServer
};
/* Clean out old rate limiters */
setInterval(function () {
if (instance == null) return;
let cleaned = 0;
const keys = instance.ipThrottle.keys();
for (const key of keys) {
if (instance.ipThrottle.get(key).lastRefill < Date.now() - 60000) {
const bucket = instance.ipThrottle.delete(key);
for (const k in bucket) delete bucket[k];
cleaned++;
}
}
if (cleaned > 0) {
LOGGER.info('Cleaned up %d stale IP throttle token buckets', cleaned);
}
}, 5 * 60 * 1000);
function getCorsAllowCallback() {
let origins = Array.prototype.slice.call(Config.get('io.cors.allowed-origins'));
origins = origins.concat([
Config.get('io.domain'),
Config.get('https.domain')
]);
return function corsOriginAllowed(origin, callback) {
if (!origin) {
// Non-browser clients might not care about Origin, allow these.
callback(null, true);
return;
}
// Different ports are technically cross-origin; a distinction that does not matter to CyTube.
origin = origin.replace(/:\d+$/, '');
if (origins.includes(origin)) {
callback(null, true);
} else {
LOGGER.warn('Rejecting origin "%s"; allowed origins are %j', origin, origins);
callback(new Error('Invalid origin'));
}
};
}