Telethon/network/authenticator.py
2016-08-28 19:26:06 +02:00

208 lines
8.4 KiB
Python

# This file is based on TLSharp
# https://github.com/sochix/TLSharp/blob/master/TLSharp.Core/Auth/Authenticator.cs
# https://github.com/sochix/TLSharp/blob/master/TLSharp.Core/Auth/Step1_PQRequest.cs
# https://github.com/sochix/TLSharp/blob/master/TLSharp.Core/Auth/Step2_DHExchange.cs
# https://github.com/sochix/TLSharp/blob/master/TLSharp.Core/Auth/Step3_CompleteDHExchange.cs
from network.mtproto_plain_sender import MtProtoPlainSender
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
import rsa
def do_authentication(transport):
sender = MtProtoPlainSender(transport)
# Step 1 sending: PQ Request
nonce = utils.generate_random_bytes(16)
with BinaryWriter() as writer:
writer.write_int(0x60469778) # Constructor number
writer.write(nonce)
sender.send(writer.get_bytes())
# Step 1 response: PQ Request
with BinaryReader(sender.receive()) as reader:
response_code = reader.read_int()
if response_code != 0x05162463:
raise AssertionError('Invalid response code: {}'.format(hex(response_code)))
nonce_from_server = reader.read(16)
if nonce_from_server != nonce:
raise AssertionError('Invalid nonce from server')
server_nonce = reader.read(16)
pq_bytes = reader.tgread_bytes()
pq = int.from_bytes(pq_bytes, byteorder='big')
vector_id = reader.read_int()
if vector_id != 0x1cb5c415:
raise AssertionError('Invalid vector constructor ID: {}'.format(hex(response_code)))
fingerprints = []
fingerprint_count = reader.read_int()
for _ in range(fingerprint_count):
fingerprints.append(reader.read(8))
# Step 2 sending: DH Exchange
new_nonce = utils.generate_random_bytes(32)
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)
# TODO, CHANGE TO_BYTE_ARRAY TO PACK(...); But idk size. And down too.
pq_inner_data_writer.tgwrite_bytes(min(p, q).to_byte_array_unsigned())
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
for fingerprint in fingerprints:
cipher_text = rsa.encrypt(str(fingerprint, encoding='utf-8').replace('-', ''),
pq_inner_data_writer.get_bytes())
if cipher_text is not None:
target_fingerprint = fingerprint
break
if cipher_text is None:
raise AssertionError('Could not find a valid key for fingerprints: {}'
.format(', '.join([str(f, encoding='utf-8') for f in fingerprints])))
with BinaryWriter() as req_dh_params_writer:
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(max(p, q).to_byte_array_unsigned())
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();
# Step 2 response: DH Exchange
with BinaryReader(sender.receive()) as reader:
response_code = reader.read_int()
if response_code == 0x79cb045d:
raise AssertionError('Server DH params fail: TODO')
if response_code != 0xd0e8075c:
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')
return None
"""
server_nonce_from_server = reader.read(16)
# TODO:
"""
if server_nonce_from_server != server_nonce:
print('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)
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)
if code != 0xb5890dba:
raise AssertionError('Invalid DH Inner Data code: {}'.format(code))
nonce_from_server1 = dh_inner_data_reader.read(16)
if nonce_from_server1 != nonce:
raise AssertionError('Invalid nonce in encrypted answer')
server_nonce_from_server1 = dh_inner_data_reader.read(16)
if server_nonce_from_server1 != server_nonce:
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')
ga = int.from_bytes(dh_inner_data_reader.tgread_bytes(), byteorder='big')
server_time = dh_inner_data_reader.read_int()
time_offset = server_time - int(time.time())
b = int.from_bytes(utils.generate_random_bytes(2048), byteorder='big')
gb = pow(g, b, dh_prime) # BigInteger.ValueOf(g).ModPow(b, dhPrime)
gab = pow(ga, b, dh_prime) # ga.ModPow(b, dhPrime)
# Prepare client DH Inner Data
with BinaryWriter() as client_dh_inner_data_writer:
client_dh_inner_data_writer.write_int(0x6643b654) # Client DH Inner Data
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())
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(client_dh_inner_data_writer.get_bytes())
client_dh_inner_data_bytes = client_dh_inner_data_with_hash_writer.get_bytes()
# Encryption
client_dh_inner_data_encrypted_bytes = aes.encrypt(client_dh_inner_data_bytes)
# Prepare Set client DH params
with BinaryWriter() as set_client_dh_params_writer:
set_client_dh_params_writer.write_int(0xf5045f1f)
set_client_dh_params_writer.write(nonce)
set_client_dh_params_writer.write(server_nonce)
set_client_dh_params_writer.tgwrite_bytes(client_dh_inner_data_encrypted_bytes)
set_client_dh_params_bytes = set_client_dh_params_writer.get_bytes()
sender.send(set_client_dh_params_bytes)
# Step 3 response: Complete DH Exchange
with BinaryReader(sender.receive()) as reader:
code = reader.read_int(signed=False)
if code == 0x3bcbf734:
nonce_from_server = reader.read(16)
# TODO:
"""
if nonce_from_server != nonce:
print('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')
return None
"""
new_nonce_hash1 = reader.read(16)
auth_key = AuthKey(gab)
new_nonce_hash_calculated = auth_key.calc_new_nonce_hash(new_nonce, 1)
if new_nonce_hash1 != new_nonce_hash_calculated:
raise AssertionError('Invalid new nonce hash')
return auth_key, time_offset
elif code == 0x46dc1fb9: # DH Gen Retry
raise NotImplementedError('dh_gen_retry')
elif code == 0xa69dae02: # DH Gen Fail
raise NotImplementedError('dh_gen_fail')
else:
raise AssertionError('DH Gen unknown: {}'.format(hex(code)))