Reviewed authenticator.py

network/authenticator.py

@@ -9,7 +9,6 @@ from utils.binary_writer import BinaryWriter
 from utils.binary_reader import BinaryReader
 from utils.factorizator import Factorizator
 from utils.auth_key import AuthKey
-from hashlib import sha1
 import utils.helpers as utils
 import time
 import pyaes
@@ -27,8 +26,9 @@ def do_authentication(transport):
         sender.send(writer.get_bytes())
 
     # Step 1 response: PQ Request
+    pq, pq_bytes, server_nonce, fingerprints = None, None, None, []
     with BinaryReader(sender.receive()) as reader:
-        response_code = reader.read_int()
+        response_code = reader.read_int(signed=False)
         if response_code != 0x05162463:
             raise AssertionError('Invalid response code: {}'.format(hex(response_code)))
 
@@ -55,15 +55,14 @@ def do_authentication(transport):
     p, q = Factorizator.factorize(pq)
     with BinaryWriter() as pq_inner_data_writer:
         pq_inner_data_writer.write_int(0x83c95aec)  # PQ Inner Data
-        pq_inner_data_writer.tgwrite_bytes(pq_bytes)
+        pq_inner_data_writer.tgwrite_bytes(utils.get_byte_array(pq, signed=False))
-        # TODO, CHANGE TO_BYTE_ARRAY TO PACK(...); But idk size. And down too.
+        pq_inner_data_writer.tgwrite_bytes(utils.get_byte_array(min(p, q), signed=False))
-        pq_inner_data_writer.tgwrite_bytes(min(p, q).to_byte_array_unsigned())
+        pq_inner_data_writer.tgwrite_bytes(utils.get_byte_array(max(p, q), signed=False))
-        pq_inner_data_writer.tgwrite_bytes(max(p, q).to_byte_array_unsigned())
         pq_inner_data_writer.write(nonce)
         pq_inner_data_writer.write(server_nonce)
         pq_inner_data_writer.write(new_nonce)
 
-        cipher_text = None
+        cipher_text, target_fingerprint = None, None
         for fingerprint in fingerprints:
             cipher_text = rsa.encrypt(str(fingerprint, encoding='utf-8').replace('-', ''),
                                       pq_inner_data_writer.get_bytes())
@@ -80,16 +79,18 @@ def do_authentication(transport):
             req_dh_params_writer.write_int(0xd712e4be)  # Req DH Params
             req_dh_params_writer.write(nonce)
             req_dh_params_writer.write(server_nonce)
-            req_dh_params_writer.tgwrite_bytes(min(p, q).to_byte_array_unsigned())
+            req_dh_params_writer.tgwrite_bytes(utils.get_byte_array(min(p, q), signed=False))
-            req_dh_params_writer.tgwrite_bytes(max(p, q).to_byte_array_unsigned())
+            req_dh_params_writer.tgwrite_bytes(utils.get_byte_array(max(p, q), signed=False))
-            req_dh_params_writer.Write(target_fingerprint);
+            req_dh_params_writer.Write(target_fingerprint)
             req_dh_params_writer.tgwrite_bytes(cipher_text)
 
-            req_dh_params_bytes = req_dh_params_writer.get_bytes();
+            req_dh_params_bytes = req_dh_params_writer.get_bytes()
+            sender.send(req_dh_params_bytes)
 
     # Step 2 response: DH Exchange
+    encrypted_answer = None
     with BinaryReader(sender.receive()) as reader:
-        response_code = reader.read_int()
+        response_code = reader.read_int(signed=False)
 
         if response_code == 0x79cb045d:
             raise AssertionError('Server DH params fail: TODO')
@@ -98,26 +99,21 @@ def do_authentication(transport):
             raise AssertionError('Invalid response code: {}'.format(hex(response_code)))
 
         nonce_from_server = reader.read(16)
-        # TODO:
-        """
         if nonce_from_server != nonce:
-            print('Invalid nonce from server')
+            raise NotImplementedError('Invalid nonce from server')
-            return None
-        """
 
         server_nonce_from_server = reader.read(16)
-        # TODO:
-        """
         if server_nonce_from_server != server_nonce:
-            print('Invalid server nonce from server')
+            raise NotImplementedError('Invalid server nonce from server')
-            return None
+
-        """
         encrypted_answer = reader.tgread_bytes()
 
     # Step 3 sending: Complete DH Exchange
     key, iv = utils.generate_key_data_from_nonces(server_nonce, new_nonce)
     aes = pyaes.AESModeOfOperationCFB(key, iv, 16)
     plain_text_answer = aes.decrypt(encrypted_answer)
+
+    g, dh_prime, ga, time_offset = None, None, None, None
     with BinaryReader(plain_text_answer.encode('ascii')) as dh_inner_data_reader:
         hashsum = dh_inner_data_reader.read(20)
         code = dh_inner_data_reader.read_int(signed=False)
@@ -133,15 +129,15 @@ def do_authentication(transport):
             raise AssertionError('Invalid server nonce in encrypted answer')
 
         g = dh_inner_data_reader.read_int()
-        dh_prime = int.from_bytes(dh_inner_data_reader.tgread_bytes(), byteorder='big')
+        dh_prime = int.from_bytes(dh_inner_data_reader.tgread_bytes(), byteorder='big', signed=True)
-        ga = int.from_bytes(dh_inner_data_reader.tgread_bytes(), byteorder='big')
+        ga = int.from_bytes(dh_inner_data_reader.tgread_bytes(), byteorder='big', signed=True)
 
         server_time = dh_inner_data_reader.read_int()
-        time_offset = server_time - int(time.time())
+        time_offset = server_time - int(time.time() * 1000)  # Multiply by 1000 to get milliseconds
 
     b = int.from_bytes(utils.generate_random_bytes(2048), byteorder='big')
-    gb = pow(g, b, dh_prime)  # BigInteger.ValueOf(g).ModPow(b, dhPrime)
+    gb = pow(g, b, dh_prime)
-    gab = pow(ga, b, dh_prime)  # ga.ModPow(b, dhPrime)
+    gab = pow(ga, b, dh_prime)
 
     # Prepare client DH Inner Data
     with BinaryWriter() as client_dh_inner_data_writer:
@@ -149,10 +145,10 @@ def do_authentication(transport):
         client_dh_inner_data_writer.write(nonce)
         client_dh_inner_data_writer.write(server_nonce)
         client_dh_inner_data_writer.write_long(0)  # TODO retry_id
-        client_dh_inner_data_writer.tgwrite_bytes(gb.to_byte_array_unsigned())
+        client_dh_inner_data_writer.tgwrite_bytes(utils.get_byte_array(gb, signed=False))
 
         with BinaryWriter() as client_dh_inner_data_with_hash_writer:
-            client_dh_inner_data_with_hash_writer.write(sha1(client_dh_inner_data_writer.get_bytes()))
+            client_dh_inner_data_with_hash_writer.write(utils.sha1(client_dh_inner_data_writer.get_bytes()))
             client_dh_inner_data_with_hash_writer.write(client_dh_inner_data_writer.get_bytes())
             client_dh_inner_data_bytes = client_dh_inner_data_with_hash_writer.get_bytes()
 
@@ -172,22 +168,15 @@ def do_authentication(transport):
     # Step 3 response: Complete DH Exchange
     with BinaryReader(sender.receive()) as reader:
         code = reader.read_int(signed=False)
-        if code == 0x3bcbf734:
+        if code == 0x3bcbf734:  # DH Gen OK
             nonce_from_server = reader.read(16)
-            # TODO:
-            """
             if nonce_from_server != nonce:
-                print('Invalid nonce from server')
+                raise NotImplementedError('Invalid nonce from server')
-                return None
-            """
 
             server_nonce_from_server = reader.read(16)
-            # TODO:
-            """
             if server_nonce_from_server != server_nonce:
-                print('Invalid server nonce from server')
+                raise NotImplementedError('Invalid server nonce from server')
-                return None
+
-            """
             new_nonce_hash1 = reader.read(16)
             auth_key = AuthKey(gab)
 

parser/tl_generator.py

@@ -297,8 +297,8 @@ def write_onresponse_code(builder, arg, args, name=None):
     if arg.is_vector:
         builder.writeln("reader.read_int()  # Vector's constructor ID")
         builder.writeln('{} = []  # Initialize an empty list'.format(name))
-        builder.writeln('{}_len = reader.read_int()'.format(name))
+        builder.writeln('{}_len = reader.read_int()'.format(arg.name))
-        builder.writeln('for _ in range({}_len):'.format(name))
+        builder.writeln('for _ in range({}_len):'.format(arg.name))
         # Temporary disable .is_vector, not to enter this if again
         arg.is_vector = False
         write_onresponse_code(builder, arg, args, name='{}_item'.format(arg.name))

utils/auth_key.py

@@ -1,6 +1,6 @@
 # This file is based on TLSharp
 # https://github.com/sochix/TLSharp/blob/master/TLSharp.Core/MTProto/Crypto/AuthKey.cs
-from hashlib import sha1
+import utils.helpers as utils
 from utils.binary_writer import BinaryWriter
 from utils.binary_reader import BinaryReader
 
@@ -8,23 +8,22 @@ from utils.binary_reader import BinaryReader
 class AuthKey:
     def __init__(self, gab=None, data=None):
         if gab:
-            self.key = gab.to_byte_array_unsigned()
+            self.key = utils.get_byte_array(gab, signed=False)
         elif data:
             self.key = data
         else:
             raise AssertionError('Either a gab integer or data bytes array must be provided')
 
-        with BinaryReader(sha1(self.key)) as reader:
+        with BinaryReader(utils.sha1(self.key)) as reader:
             self.aux_hash = reader.read_long(signed=False)
             reader.read(4)
             self.key_id = reader.read_long(signed=False)
 
-
     def calc_new_nonce_hash(self, new_nonce, number):
         with BinaryWriter() as writer:
             writer.write(new_nonce)
             writer.write_byte(number)
             writer.write_long(self.aux_hash, signed=False)
 
-            new_nonce_hash = sha1(writer.get_bytes())[4:20]
+            new_nonce_hash = utils.sha1(writer.get_bytes())[4:20]
             return new_nonce_hash

utils/helpers.py

@@ -1,11 +1,14 @@
 import os
 from utils.binary_writer import BinaryWriter
-from hashlib import sha1
+import hashlib
+
+
+bits_per_byte = 8
 
 
 def generate_random_long(signed=True):
     """Generates a random long integer (8 bytes), which is optionally signed"""
-    return int.from_bytes(os.urandom(8), signed=signed)
+    return int.from_bytes(os.urandom(8), signed=signed, byteorder='big')
 
 
 def generate_random_bytes(count):
@@ -13,27 +16,20 @@ def generate_random_bytes(count):
     return os.urandom(count)
 
 
+def get_byte_array(integer, signed):
+    bits = integer.bit_length()
+    byte_length = (bits + bits_per_byte - 1) // bits_per_byte
+    return int.to_bytes(integer, length=byte_length, byteorder='big', signed=signed)
+
+
 def calc_key(shared_key, msg_key, client):
     """Calculate the key based on Telegram guidelines, specifying whether it's the client or not"""
     x = 0 if client else 8
 
-    buffer = [0] * 48
+    sha1a = sha1(msg_key + shared_key[x:x + 32])
-    buffer[0:16] = msg_key
+    sha1b = sha1(shared_key[x + 32:x + 48] + msg_key + shared_key[x + 48:x + 64])
-    buffer[16:48] = shared_key[x:x + 32]
+    sha1c = sha1(shared_key[x + 64:x + 96] + msg_key)
-    sha1a = sha1(buffer)
+    sha1d = sha1(msg_key + shared_key[x + 96:x + 128])
-
-    buffer[0:16] = shared_key[x + 32:x + 48]
-    buffer[16:32] = msg_key
-    buffer[32:48] = shared_key[x + 48:x + 64]
-    sha1b = sha1(buffer)
-
-    buffer[0:32] = shared_key[x + 64:x + 96]
-    buffer[32:48] = msg_key
-    sha1c = sha1(buffer)
-
-    buffer[0:16] = msg_key
-    buffer[16:48] = shared_key[x + 96:x + 128]
-    sha1d = sha1(buffer)
 
     key = sha1a[0:8] + sha1b[8:20] + sha1c[4:16]
     iv = sha1a[8:20] + sha1b[0:8] + sha1c[16:20] + sha1d[0:8]
@@ -48,43 +44,27 @@ def calc_msg_key(data):
 
 def calc_msg_key_offset(data, offset, limit):
     """Calculates the message key from offset given data, with an optional offset and limit"""
-    # TODO untested, may not be offset like this
-    # In the original code it was as parameters for the sha function, not slicing the array
     return sha1(data[offset:offset + limit])[4:20]
 
 
-def generate_key_data_from_nonces(serverNonce, newNonce):
+def generate_key_data_from_nonces(server_nonce, new_nonce):
-    # TODO unsure that this works
+    hash1 = sha1(bytes(new_nonce + server_nonce))
-    nonces = [0] * 48
+    hash2 = sha1(bytes(server_nonce + new_nonce))
+    hash3 = sha1(bytes(new_nonce + new_nonce))
 
-    nonces[00:32] = newNonce
+    with BinaryWriter() as key_buffer:
-    nonces[32:48] = serverNonce
+        with BinaryWriter() as iv_buffer:
-    hash1 = hash(bytes(nonces))
+            key_buffer.write(hash1)
+            key_buffer.write(hash2[:12])
 
-    nonces[00:16] = serverNonce
+            iv_buffer.write(hash2[12:20])
-    nonces[16:32] = newNonce
+            iv_buffer.write(hash3)
-    hash2 = hash(bytes(nonces))
+            iv_buffer.write_byte(new_nonce[:4])
 
-    nonces = [0] * 64
+            return key_buffer.get_bytes(), iv_buffer.get_bytes()
-    nonces[00:32] = newNonce
-    nonces[32:64] = newNonce
-    hash2 = hash(bytes(nonces))
 
-    with BinaryWriter() as keyBuffer:
-        with BinaryWriter() as ivBuffer:
-            """
-                using (var keyBuffer = new MemoryStream(32))
-                using (var ivBuffer = new MemoryStream(32))
-                {
-                    keyBuffer.Write(hash1, 0, hash1.Length);
-                    keyBuffer.Write(hash2, 0, 12);
 
-                    ivBuffer.Write(hash2, 12, 8);
+def sha1(data):
-                    ivBuffer.Write(hash3, 0, hash3.Length);
+    sha = hashlib.sha1
-                    ivBuffer.Write(newNonce, 0, 4);
+    sha.update(data)
-
+    return sha.digest()
-                    return new AESKeyData(keyBuffer.ToArray(), ivBuffer.ToArray());
-                }
-            """
-            # TODO implement
-            raise NotImplementedError()