user authentication, start building out services

src/communicator.js

@@ -0,0 +1,106 @@
+const { FLAP, SNAC, TLV } = require('./structures');
+const { logDataStream } = require('./util');
+const { FLAGS_EMPTY } = require('./consts');
+
+const AuthorizationRegistrationService = require("./services/authorization-registration");
+
+class Communicator {
+  constructor(socket) {
+    // Hold on to the socket
+    this.socket = socket;
+
+    this.socket.on('data', (data) => {
+      console.log('DATA-----------------------');
+      console.log('RECV', logDataStream(Buffer.from(data, 'hex')));
+      const flap = FLAP.fromBuffer(Buffer.from(data, 'hex'));
+      console.log('RECV', flap.toString());
+      this.handleMessage(flap);
+    });
+
+    this._sequenceNumber = 0;
+
+    this.registerServices();
+
+    this.start();
+  }
+
+  start() {
+    // Start negotiating a connection 
+    const hello = new FLAP(0x01, 0, Buffer.from([0x00, 0x00, 0x00, 0x01]));
+    this.send(hello);
+  }
+
+  registerServices() {
+    const services = [
+      new AuthorizationRegistrationService(this),
+    ];
+
+    this.services = {};
+    services.forEach((service) => {
+      this.services[service.family] = service;
+    });
+  }
+
+  _getNewSequenceNumber() {
+    return ++this._sequenceNumber;
+  }
+
+  send(message) {
+    console.log('SEND', message.toString());
+    console.log('SEND', logDataStream(message.toBuffer()));
+    console.log('-----------------------DATA');
+    this.socket.write(message.toBuffer());
+  }
+
+  handleMessage(message) {
+    switch (message.channel) {
+      case 1:
+        const protocol = message.payload.readUInt32BE();
+        
+        if (protocol !== 1) {
+          console.log('Unsupported protocol:', protocol);
+          this.socket.end();
+          return;
+        }
+
+        if (message.payload.length <= 4) {
+          return;
+        }
+
+        const tlv = TLV.fromBuffer(message.payload.slice(4));
+        console.log(tlv.toString());
+
+        switch (tlv.type) {
+          case 0x06: // Requesting available services
+            const resp = new FLAP(2, this._getNewSequenceNumber(), new SNAC(0x01, 0x03, FLAGS_EMPTY, 0, [
+              Buffer.from([0x00, 0x01, 0x00, 0x02, 0x00, 0x03, 0x00, 0x04,
+                           0x00, 0x06, 0x00, 0x08, 0x00, 0x09, 0x00, 0x0A,
+                           0x00, 0x0B, 0x00, 0x0C, 0x00, 0x13, 0x00, 0x15,
+                          ]), // Buddy List management service
+            ]));
+            this.send(resp);
+            return;
+        }
+
+        return;
+      case 2:
+        if (!message.payload) {
+          console.error('No SNAC');
+          return;
+        }
+
+        const familyService = this.services[message.payload.family];
+        if (!familyService) {
+          console.warn('no handler for family', message.payload.family);
+          return;
+        }
+
+        familyService.handleMessage(message);
+      default:
+        console.warn('No handlers for channel', message.channel);
+        return;
+    }
+  }
+}
+
+module.exports = Communicator;

src/consts.js

@@ -0,0 +1,7 @@
+const AIM_MD5_STRING = "AOL Instant Messenger (SM)";
+const FLAGS_EMPTY = Buffer.from([0x00, 0x00, 0x00, 0x00]);
+
+module.exports = {
+  AIM_MD5_STRING,
+  FLAGS_EMPTY,
+};

src/index.js

@@ -1,78 +1,29 @@
 const net = require('net');
-const { logDataStream } = require('./util');
-const { FLAP } = require('./structures');
+const Communicator = require('./communicator');
+
+const communicators = {};
 
 const server = net.createServer((socket) => {
   console.log('client connected...');
-  socket.setTimeout(5000);
+  socket.setTimeout(30000);
 
   socket.on('error', (e) => {
     console.error('socket encountered an error:', e);
-  });
-
-  socket.on('data', (data) => {
-    const flap = FLAP.fromBuffer(Buffer.from(data, 'hex'));
-    console.log('RECV', flap.toString());
+    delete communicators[socket];
   });
 
   socket.on('timeout', () => {
     console.log('socket timeout');
     socket.end();
-  })
+    delete communicators[socket];
+  });
 
   socket.on('end', () => {
     console.log('client disconnected...');
   });
 
-  const hello = new FLAP(0x01, 0, Buffer.from([0x00, 0x00, 0x00, 0x01]));
-  socket.write(hello.toBuffer());
-
-  /* 1. on connection, server sends
-
-    2a      FLAP
-    01      channel 1
-    00 01   datagram #1
-    00 04   4 bytes of data 
-    00 00 00 1
-  */
-
-  /* 2. client responds
-    2a      FLAP
-    01      channel 1
-    51 11   datagram 11
-    00 04   4 bytes
-    00 00 00 01
-  */
-
-  /* 3. client sends username
-    2a            FLAP
-    02            channel 2 (SNAC)
-    51 12         datagram 12
-    00 12         18 bytes of data
-    00 17         Service (Authorization/registration service)
-    00 06         Family  (Request md5 authkey)
-    00 00         Flags
-    00 00 00 00   SNAC request id
-    00 01         TLV.Type(0x01) - screen name
-    00 04         TLV.Length (4)
-    74 6f 6f 66   toof
-  */
-
-  /* 4. server responds
-    2a          FLAP
-    02          Channel 2 (SNAC)
-    00 02       datagram 2
-    00 16       22 bytes
-    00 17       Service (Authorization/registration service)
-    00 07       Server md5 authkey response
-                This snac contain server generated auth key. Client should use it to crypt password.
-    00 00       Flags
-    00 00 00 00 SNAC request ID
-    00 0a       Length (10 bytes)
-    ...
-  */
-
-
+  const c = new Communicator(socket);
+  communicators[socket] = c;
 });
 
 server.on('error', (err) => {

src/services/authorization-registration.js

@@ -0,0 +1,79 @@
+const crypto = require('crypto');
+const BaseService = require('./base');
+const { FLAP, SNAC, TLV } = require('../structures');
+
+const { AIM_MD5_STRING, FLAGS_EMPTY } = require('../consts');
+
+const users = {
+  toof: 'foo',
+};
+
+class AuthorizationRegistrationService extends BaseService {
+  constructor(communicator) {
+    super({ family: 0x17, version: 0x01 }, communicator);
+    this.cipher = "HARDY";
+  }
+
+  handleMessage(message) {
+    switch (message.payload.service) {
+      case 0x02: // Client login request (md5 login sequence)
+        const tlvs = message.payload.tlvs;
+        const clientNameTLV = tlvs.find((tlv) => tlv.type === 0x03);
+        console.log("Attempting connection from", clientNameTLV.payload.toString('ascii'));
+
+        const userTLV = tlvs.find((tlv) => tlv.type === 0x01);
+        const username = userTLV.payload.toString('ascii');
+
+        if (!users[username]) {
+          const authResp = new FLAP(2, this._getNewSequenceNumber(),
+          new SNAC(0x17, 0x03, FLAGS_EMPTY, 0, [
+            new TLV(0x0001, Buffer.from(username)), // username
+            new TLV(0x0008, Buffer.from([0x00, 0x04])) // incorrect nick/password
+          ]));
+          
+          this.send(authResp);
+          return;
+        }
+
+        const passwordHashTLV = tlvs.find((tlv) => tlv.type === 0x25);
+
+        const pwHash = crypto.createHash('md5');
+        pwHash.update(this.cipher);
+        pwHash.update(users[username]);
+        pwHash.update(AIM_MD5_STRING);
+        const digest = pwHash.digest('hex');
+
+        if (digest !== passwordHashTLV.payload.toString('hex')) {
+          console.log('Invalid password for', username);
+          const authResp = new FLAP(2, this._getNewSequenceNumber(),
+          new SNAC(0x17, 0x03, FLAGS_EMPTY, 0, [
+            new TLV(0x0001, Buffer.from(username)), // username
+            new TLV(0x0008, Buffer.from([0x00, 0x04])) // incorrect nick/password
+          ]));
+          this.send(authResp);
+          return;
+        }
+
+        const authResp = new FLAP(2, this._getNewSequenceNumber(),
+        new SNAC(0x17, 0x03, FLAGS_EMPTY, 0, [
+          new TLV(0x01, Buffer.from(username)), // username
+          new TLV(0x05, Buffer.from('10.0.1.29:5190')), // BOS address
+          new TLV(0x06, Buffer.from('im a cookie uwu')) // Authorization cookie
+        ]));
+
+        this.send(authResp);
+        return;
+      case 0x06: // Request md5 authkey
+        const payload = Buffer.alloc(2, 0xFF, 'hex');
+        payload.writeUInt16BE(this.cipher.length);
+        const md5ReqResp = new FLAP(2, this._getNewSequenceNumber(),
+          new SNAC(0x17, 0x07, FLAGS_EMPTY, 0, [
+            Buffer.concat([payload, Buffer.from(this.cipher, 'binary')]),
+          ]));
+        this.send(md5ReqResp);
+        break;
+    }
+  }
+}
+
+module.exports = AuthorizationRegistrationService;

src/services/base.js

@@ -0,0 +1,21 @@
+class BaseService {
+  constructor({family, version}, communicator) {
+    this.family = family;
+    this.version = version;
+    this.communicator = communicator;
+  }
+
+  send(message) {
+    this.communicator.send(message);
+  }
+
+  _getNewSequenceNumber() {
+    return this.communicator._getNewSequenceNumber();
+  }
+
+  handleMessage(message) {
+    return null;
+  }
+}
+
+module.exports = BaseService;

src/structures.js

@@ -18,7 +18,7 @@ class TLV {
   }
 
   toString() {
-    return `TLV(${this.type}, ${this.len}, ${this.payload.toString('ascii')})`;
+    return `TLV(0x${this.type.toString(16).padStart(2, '0')}, ${this.len}, ${this.payload.toString('ascii')})`;
   }
 
   toBuffer() {
@@ -35,14 +35,14 @@ class SNAC {
     const service = buf.slice(2,4).readInt16BE(0);
     const flags = buf.slice(4, 6);
     const requestID = buf.slice(6, 10).readInt32BE(0);
-    const payload = []; // SNACs can have multiple TLVs
+    const tlvs = []; // SNACs can have multiple TLVs
 
-    let payloadIdx = 10;
-    let cb = 0, cbLimit = 10; //circuit breaker
-    while (payloadIdx < payloadLength && cb < cbLimit) {
-      const tlv = TLV.fromBuffer(buf.slice(payloadIdx));
-      payload.push(tlv);
-      payloadIdx += tlv.len + 4; // 4 bytes for TLV type + payload length
+    let tlvsIdx = 10;
+    let cb = 0, cbLimit = 20; //circuit breaker
+    while (tlvsIdx < payloadLength && cb < cbLimit) {
+      const tlv = TLV.fromBuffer(buf.slice(tlvsIdx));
+      tlvs.push(tlv);
+      tlvsIdx += tlv.len + 4; // 4 bytes for TLV type + tlvs length
       cb++;
     }
     if (cb === cbLimit) {
@@ -50,19 +50,19 @@ class SNAC {
       process.exit(1);
     }
     
-    return new SNAC(family, service, flags, requestID, payload);
+    return new SNAC(family, service, flags, requestID, tlvs);
   }
 
-  constructor(family, service, flags, requestID, payload) {
+  constructor(family, service, flags, requestID, tlvs = []) {
     this.family = family;
     this.service = service;
     this.flags = flags;
     this.requestID = requestID;
-    this.payload = payload;
+    this.tlvs = tlvs;
   }
 
   toString() {
-    return `SNAC(${this.family.toString(16)},${this.service.toString(16)}) #${this.requestID}\n  ${this.payload}`;
+    return `SNAC(${this.family.toString(16)},${this.service.toString(16)}) #${this.requestID}\n  ${this.tlvs}`;
   }
 
   toBuffer() {
@@ -72,7 +72,13 @@ class SNAC {
     SNACHeader.writeUInt16BE(this.flags, 4);
     SNACHeader.writeUInt32BE(this.requestID, 6);
 
-    const payload = this.payload.map((tlv) => tlv.toBuffer());
+    const payload = this.tlvs.map((thing) => {
+      if (thing instanceof TLV) {
+        return thing.toBuffer();
+      }
+      return thing;
+    });
+
     return Buffer.concat([SNACHeader, ...payload]);
   }
 }
@@ -80,17 +86,21 @@ class SNAC {
 class FLAP {
   static fromBuffer(buf) {
     assert.equal(buf[0], 0x2a, 'Expected 0x2a FLAP header');
-    const channel = parseInt(buf[1], 16);
-    const datagramNumber = buf.slice(2,4).readInt16BE(0);
+    const channel = buf.readInt8(1);
+    const sequenceNumber = buf.slice(2,4).readInt16BE(0);
     const payloadLength = buf.slice(4, 6).readInt16BE(0);
-    const payload = buf.slice(6, 6 + payloadLength);
+    let payload = buf.slice(6, 6 + payloadLength);
 
-    return new FLAP(channel, datagramNumber, payload)
+    if (channel === 2) {
+      payload = SNAC.fromBuffer(payload, payloadLength);
     }
 
-  constructor(channel, datagramNumber, payload) {
+    return new FLAP(channel, sequenceNumber, payload)
+  }
+
+  constructor(channel, sequenceNumber, payload) {
     this.channel = channel;
-    this.datagramNumber = datagramNumber;
+    this.sequenceNumber = sequenceNumber;
 
     this.payload = payload;
     this.payloadLength = this.payload.length;
@@ -98,23 +108,19 @@ class FLAP {
     if (payload instanceof SNAC) {
       this.payloadLength = payload.toBuffer().length;
     }
-
-    if (channel === 2 && !(payload instanceof SNAC)) {
-      this.payload = SNAC.fromBuffer(this.payload, this.payloadLength);
-    }
   }
 
   toString() {
     const hasSnac = this.payload instanceof SNAC;
     const payload = hasSnac ? this.payload.toString() : logDataStream(this.payload).split('\n').join('\n  ');
-    return `ch:${this.channel}, dn: ${this.datagramNumber}, len: ${this.payloadLength}, payload:\n  ${payload}`
+    return `ch:${this.channel}, dn: ${this.sequenceNumber}, len: ${this.payloadLength}, payload:\n  ${payload}`
   }
 
   toBuffer() {
     const FLAPHeader = Buffer.alloc(6, 0, 'hex');
     FLAPHeader.writeInt8(0x2a, 0);
     FLAPHeader.writeInt8(this.channel, 1);
-    FLAPHeader.writeInt16BE(this.datagramNumber, 2);
+    FLAPHeader.writeInt16BE(this.sequenceNumber, 2);
     FLAPHeader.writeInt16BE(this.payloadLength, 4);
 
     let payload = this.payload;