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Reviewed authenticator.py

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Lonami 2016-08-30 17:40:49 +02:00
parent e712a9bf61
commit 12cb66ab2c
4 changed files with 66 additions and 98 deletions
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69
network/authenticator.py
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@ -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)
# 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.tgwrite_bytes(utils.get_byte_array(pq, signed=False))
pq_inner_data_writer.tgwrite_bytes(utils.get_byte_array(min(p, q), signed=False))
pq_inner_data_writer.tgwrite_bytes(utils.get_byte_array(max(p, q), signed=False))
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(max(p, q).to_byte_array_unsigned())
req_dh_params_writer.Write(target_fingerprint);
req_dh_params_writer.tgwrite_bytes(utils.get_byte_array(min(p, q), signed=False))
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.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')
return None
"""
raise NotImplementedError('Invalid nonce from server')
server_nonce_from_server = reader.read(16)
# TODO:
"""
if server_nonce_from_server != server_nonce:
print('Invalid server nonce from server')
return None
"""
raise NotImplementedError('Invalid server nonce from server')
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')
ga = 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', 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)
gab = pow(ga, b, dh_prime) # ga.ModPow(b, dhPrime)
gb = pow(g, b, dh_prime)
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')
return None
"""
raise NotImplementedError('Invalid nonce from server')
server_nonce_from_server = reader.read(16)
# TODO:
"""
if server_nonce_from_server != server_nonce:
print('Invalid server nonce from server')
return None
"""
raise NotImplementedError('Invalid server nonce from server')
new_nonce_hash1 = reader.read(16)
auth_key = AuthKey(gab)

4
parser/tl_generator.py
View File

@ -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('for _ in range({}_len):'.format(name))
builder.writeln('{}_len = reader.read_int()'.format(arg.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))

9
utils/auth_key.py
View File

@ -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

82
utils/helpers.py
View File

@ -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
buffer[0:16] = msg_key
buffer[16:48] = shared_key[x:x + 32]
sha1a = sha1(buffer)
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)
sha1a = sha1(msg_key + shared_key[x:x + 32])
sha1b = sha1(shared_key[x + 32:x + 48] + msg_key + shared_key[x + 48:x + 64])
sha1c = sha1(shared_key[x + 64:x + 96] + msg_key)
sha1d = sha1(msg_key + shared_key[x + 96:x + 128])
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):
# TODO unsure that this works
nonces = [0] * 48
def generate_key_data_from_nonces(server_nonce, new_nonce):
hash1 = sha1(bytes(new_nonce + server_nonce))
hash2 = sha1(bytes(server_nonce + new_nonce))
hash3 = sha1(bytes(new_nonce + new_nonce))
nonces[00:32] = newNonce
nonces[32:48] = serverNonce
hash1 = hash(bytes(nonces))
with BinaryWriter() as key_buffer:
with BinaryWriter() as iv_buffer:
key_buffer.write(hash1)
key_buffer.write(hash2[:12])
nonces[00:16] = serverNonce
nonces[16:32] = newNonce
hash2 = hash(bytes(nonces))
iv_buffer.write(hash2[12:20])
iv_buffer.write(hash3)
iv_buffer.write_byte(new_nonce[:4])
nonces = [0] * 64
nonces[00:32] = newNonce
nonces[32:64] = newNonce
hash2 = hash(bytes(nonces))
return key_buffer.get_bytes(), iv_buffer.get_bytes()
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);
ivBuffer.Write(hash3, 0, hash3.Length);
ivBuffer.Write(newNonce, 0, 4);
return new AESKeyData(keyBuffer.ToArray(), ivBuffer.ToArray());
}
"""
# TODO implement
raise NotImplementedError()
def sha1(data):
sha = hashlib.sha1
sha.update(data)
return sha.digest()