mirror of
https://github.com/LonamiWebs/Telethon.git
synced 2024-11-14 13:36:43 +03:00
65 lines
2.3 KiB
Python
65 lines
2.3 KiB
Python
import os
|
|
|
|
from .connection import Connection
|
|
from .tcpabridged import ConnectionTcpAbridged
|
|
from ...crypto import AESModeCTR
|
|
|
|
|
|
class ConnectionTcpObfuscated(ConnectionTcpAbridged):
|
|
"""
|
|
Mode that Telegram defines as "obfuscated2". Encodes the packet
|
|
just like `ConnectionTcpAbridged`, but encrypts every message with
|
|
a randomly generated key using the AES-CTR mode so the packets are
|
|
harder to discern.
|
|
"""
|
|
def __init__(self, ip, port, dc_id, *, loop, loggers, proxy=None):
|
|
super().__init__(
|
|
ip, port, dc_id, loop=loop, loggers=loggers, proxy=proxy)
|
|
self._aes_encrypt = None
|
|
self._aes_decrypt = None
|
|
|
|
def _write(self, data):
|
|
self._writer.write(self._aes_encrypt.encrypt(data))
|
|
|
|
async def _read(self, n):
|
|
return self._aes_decrypt.encrypt(await self._reader.readexactly(n))
|
|
|
|
async def connect(self, timeout=None, ssl=None):
|
|
# FIXME: that's an abstraction leak
|
|
await Connection.connect(self, timeout=timeout, ssl=ssl)
|
|
|
|
# Obfuscated messages secrets cannot start with any of these
|
|
keywords = (b'PVrG', b'GET ', b'POST', b'\xee\xee\xee\xee')
|
|
while True:
|
|
random = os.urandom(64)
|
|
if (random[0] != 0xef and
|
|
random[:4] not in keywords and
|
|
random[4:4] != b'\0\0\0\0'):
|
|
break
|
|
|
|
random = bytearray(random)
|
|
random_reversed = random[55:7:-1] # Reversed (8, len=48)
|
|
|
|
# Encryption has "continuous buffer" enabled
|
|
encrypt_key = self._compose_key(bytes(random[8:40]))
|
|
encrypt_iv = bytes(random[40:56])
|
|
decrypt_key = self._compose_key(bytes(random_reversed[:32]))
|
|
decrypt_iv = bytes(random_reversed[32:48])
|
|
|
|
self._aes_encrypt = AESModeCTR(encrypt_key, encrypt_iv)
|
|
self._aes_decrypt = AESModeCTR(decrypt_key, decrypt_iv)
|
|
|
|
random[56:60] = b'\xef\xef\xef\xef'
|
|
random[56:64] = self._compose_tail(bytes(random))
|
|
|
|
self._writer.write(random)
|
|
await self._writer.drain()
|
|
|
|
# Next functions provide the variable parts of the connection handshake.
|
|
# This is necessary to modify obfuscated2 the way that MTProxy requires.
|
|
def _compose_key(self, data):
|
|
return data
|
|
|
|
def _compose_tail(self, data):
|
|
return self._aes_encrypt.encrypt(data)[56:64]
|