Flatten

2 files changed, 385 insertions, 0 deletions

diff --git a/server/core/rateLimiter.js b/server/core/rateLimiter.js
new file mode 100644
index 0000000..0c2a384
--- /dev/null
+++ b/server/core/rateLimiter.js
@@ -0,0 +1,103 @@
+/**
+  * Tracks frequency of occurances based on `id` (remote address), then allows or
+  * denies command execution based on comparison with `threshold`
+  *
+  * Version: v2.0.0
+  * Developer: Marzavec ( https://github.com/marzavec )
+  * License: WTFPL ( http://www.wtfpl.net/txt/copying/ )
+  *
+  */
+
+class Police {
+  /**
+   * Create a ratelimiter instance.
+   */
+  constructor () {
+    this._records = {};
+    this._halflife = 30 * 1000; // milliseconds
+    this._threshold = 25;
+    this._hashes = [];
+  }
+
+  /**
+    * Finds current score by `id`
+    *
+    * @param {String} id target id / address
+    * @public
+    *
+    * @memberof Police
+    */
+  search (id) {
+    let record = this._records[id];
+
+    if (!record) {
+      record = this._records[id] = {
+        time: Date.now(),
+        score: 0
+      }
+    }
+
+    return record;
+  }
+
+  /**
+    * Adjusts the current ratelimit score by `deltaScore`
+    *
+    * @param {String} id target id / address
+    * @param {Number} deltaScore amount to adjust current score by
+    * @public
+    *
+    * @memberof Police
+    */
+  frisk (id, deltaScore) {
+    let record = this.search(id);
+
+    if (record.arrested) {
+      return true;
+    }
+
+    record.score *= Math.pow(2, -(Date.now() - record.time ) / this._halflife);
+    record.score += deltaScore;
+    record.time = Date.now();
+
+    if (record.score >= this._threshold) {
+      return true;
+    }
+
+    return false;
+  }
+
+  /**
+    * Statically set server to no longer accept traffic from `id`
+    *
+    * @param {String} id target id / address
+    * @public
+    *
+    * @memberof Police
+    */
+  arrest (id, hash) {
+    let record = this.search(id);
+
+    record.arrested = true;
+    this._hashes[hash] = id;
+  }
+
+  /**
+    * Remove statically assigned limit from `id`
+    *
+    * @param {String} id target id / address
+    * @public
+    *
+    * @memberof Police
+    */
+  pardon (id) {
+    if (typeof this._hashes[id] !== 'undefined') {
+      id = this._hashes[id];
+    }
+    
+    let record = this.search(id);
+    record.arrested = false;
+  }
+}
+
+module.exports = Police;
diff --git a/server/core/server.js b/server/core/server.js
new file mode 100644
index 0000000..855aeba
--- /dev/null
+++ b/server/core/server.js
@@ -0,0 +1,282 @@
+/**
+  * Main websocket server handling communications and connection events
+  *
+  * Version: v2.0.0
+  * Developer: Marzavec ( https://github.com/marzavec )
+  * License: WTFPL ( http://www.wtfpl.net/txt/copying/ )
+  *
+  */
+
+const wsServer = require('ws').Server;
+const socketReady = require('ws').OPEN;
+const crypto = require('crypto');
+const ipSalt = (Math.random().toString(36).substring(2, 16) + Math.random().toString(36).substring(2, (Math.random() * 16))).repeat(16);
+const Police = require('./rateLimiter');
+const pulseSpeed = 16000; // ping all clients every X ms
+
+class server extends wsServer {
+  /**
+   * Create a HackChat server instance.
+   *
+   * @param {Object} core Reference to the global core object
+   */
+  constructor (core) {
+    super({ port: core.config.websocketPort });
+
+    this._core = core;
+    this._police = new Police();
+    this._cmdBlacklist = {};
+    this._heartBeat = setInterval(((data) => {
+      this.beatHeart();
+    }).bind(this), pulseSpeed);
+
+    this.on('error', (err) => {
+      this.handleError('server', err);
+    });
+
+    this.on('connection', (socket, request) => {
+      this.newConnection(socket, request);
+    });
+  }
+
+  /**
+    * Send empty `ping` frame to each client
+    *
+    */
+  beatHeart () {
+    let targetSockets = this.findSockets({});
+
+    if (targetSockets.length === 0) {
+      return;
+    }
+
+    for (let i = 0, l = targetSockets.length; i < l; i++) {
+      try {
+        if (targetSockets[i].readyState === socketReady) {
+          targetSockets[i].ping();
+        }
+      } catch (e) { }
+    }
+  }
+
+  /**
+    * Bind listeners for the new socket created on connection to this class
+    *
+    * @param {Object} socket New socket object
+    * @param {Object} request Initial headers of the new connection
+    */
+  newConnection (socket, request) {
+    socket.remoteAddress = request.headers['x-forwarded-for'] || request.connection.remoteAddress;
+
+  	socket.on('message', ((data) => {
+      this.handleData(socket, data);
+    }).bind(this));
+
+    socket.on('close', (() => {
+      this.handleClose(socket);
+    }).bind(this));
+
+    socket.on('error', ((err) => {
+      this.handleError(socket, err);
+    }).bind(this));
+  }
+
+  /**
+    * Handle incoming messages from clients, parse and check command, then hand-off
+    *
+    * @param {Object} socket Calling socket object
+    * @param {String} data Message sent from client
+    */
+  handleData (socket, data) {
+    // Don't penalize yet, but check whether IP is rate-limited
+    if (this._police.frisk(socket.remoteAddress, 0)) {
+      this.reply({ cmd: 'warn', text: "Your IP is being rate-limited or blocked." }, socket);
+
+      return;
+    }
+
+    // Penalize here, but don't do anything about it
+    this._police.frisk(socket.remoteAddress, 1);
+
+    // ignore ridiculously large packets
+    if (data.length > 65536) {
+      return;
+    }
+
+    // Start sent data verification
+    var args = null;
+    try {
+      args = JSON.parse(data);
+    } catch (e) {
+      // Client sent malformed json, gtfo
+      socket.close();
+    }
+
+    if (args === null) {
+      return;
+    }
+
+    if (typeof args.cmd === 'undefined' || args.cmd == 'ping') {
+      return;
+    }
+
+    if (typeof args.cmd !== 'string') {
+      return;
+    }
+
+    if (typeof socket.channel === 'undefined' && args.cmd !== 'join') {
+      return;
+    }
+
+    if (typeof this._cmdBlacklist[args.cmd] === 'function') {
+      return;
+    }
+
+    // Finished verification, pass to command modules
+    this._core.commands.handleCommand(this, socket, args);
+  }
+
+  /**
+    * Handle socket close from clients
+    *
+    * @param {Object} socket Closing socket object
+    */
+  handleClose (socket) {
+    this._core.commands.handleCommand(this, socket, { cmd: 'disconnect' });
+  }
+
+  /**
+    * "Handle" server or socket errors
+    *
+    * @param {Object||String} socket Calling socket object, or 'server'
+    * @param {String} err The sad stuff
+    */
+  handleError (socket, err) {
+    console.log(`Server error: ${err}`);
+  }
+
+  /**
+    * Send data payload to specific socket/client
+    *
+    * @param {Object} data Object to convert to json for transmission
+    * @param {Object} socket The target client
+    */
+  send (data, socket) {
+    // Add timestamp to command
+    data.time = Date.now();
+
+    try {
+      if (socket.readyState === socketReady) {
+        socket.send(JSON.stringify(data));
+      }
+    } catch (e) { }
+  }
+
+  /**
+    * Overload function for `this.send()`
+    *
+    * @param {Object} data Object to convert to json for transmission
+    * @param {Object} socket The target client
+    */
+  reply (data, socket) {
+    this.send(data, socket);
+  }
+
+  /**
+    * Finds sockets/clients that meet the filter requirements, then passes the data to them
+    *
+    * @param {Object} data Object to convert to json for transmission
+    * @param {Object} filter see `this.findSockets()`
+    */
+  broadcast (data, filter) {
+    let targetSockets = this.findSockets(filter);
+
+    if (targetSockets.length === 0) {
+      return false;
+    }
+
+    for (let i = 0, l = targetSockets.length; i < l; i++) {
+      this.send(data, targetSockets[i]);
+    }
+
+    return true;
+  }
+
+  /**
+    * Finds sockets/clients that meet the filter requirements, returns result as array
+    *
+    * @param {Object} data Object to convert to json for transmission
+    * @param {Object} filter The socket must of equal or greater attribs matching `filter`
+    *                        = {} // matches all
+    *                        = { channel: 'programming' } // matches any socket where (`socket.channel` === 'programming')
+    *                        = { channel: 'programming', nick: 'Marzavec' } // matches any socket where (`socket.channel` === 'programming' && `socket.nick` === 'Marzavec')
+    */
+  findSockets (filter) {
+    let filterAttribs = Object.keys(filter);
+    let reqCount = filterAttribs.length;
+    let curMatch;
+    let matches = [];
+    for ( let socket of this.clients ) {
+      curMatch = 0;
+
+      for (let i = 0; i < reqCount; i++) {
+        if (typeof socket[filterAttribs[i]] !== 'undefined') {
+          switch(typeof filter[filterAttribs[i]]) {
+            case 'object': {
+              if (Array.isArray(filter[filterAttribs[i]])) {
+                if (filter[filterAttribs[i]].indexOf(socket[filterAttribs[i]]) !== -1) {
+                  curMatch++;
+                }
+              } else {
+                if (socket[filterAttribs[i]] === filter[filterAttribs[i]]) {
+                  curMatch++;
+                }
+              }
+            break;
+            }
+
+            case 'function': {
+              if (filter[filterAttribs[i]](socket[filterAttribs[i]])) {
+                curMatch++;
+              }
+            break;
+            }
+
+            default: {
+              if (socket[filterAttribs[i]] === filter[filterAttribs[i]]) {
+                curMatch++;
+              }
+            break;
+            }
+          }
+        }
+      }
+
+      if (curMatch === reqCount) {
+        matches.push(socket);
+      }
+    }
+
+    return matches;
+  }
+
+  /**
+    * Encrypts target socket's remote address using non-static variable length salt
+    * encodes and shortens the output, returns that value
+    *
+    * @param {Object||String} target Either the target socket or ip as string
+    */
+  getSocketHash (target) {
+    let sha = crypto.createHash('sha256');
+
+    if (typeof target === 'string') {
+      sha.update(target + ipSalt);
+    } else {
+      sha.update(target.remoteAddress + ipSalt);
+    }
+
+    return sha.digest('base64').substr(0, 15);
+  }
+}
+
+module.exports = server;