mirror of
https://github.com/LonamiWebs/Telethon.git
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64 lines
2.3 KiB
Python
64 lines
2.3 KiB
Python
import os
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from .connection import Connection
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from .tcpabridged import ConnectionTcpAbridged
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from ...crypto import AESModeCTR
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class ConnectionTcpObfuscated(ConnectionTcpAbridged):
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"""
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Mode that Telegram defines as "obfuscated2". Encodes the packet
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just like `ConnectionTcpAbridged`, but encrypts every message with
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a randomly generated key using the AES-CTR mode so the packets are
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harder to discern.
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"""
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def __init__(self, ip, port, dc_id, *, loop, loggers, proxy=None):
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super().__init__(
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ip, port, dc_id, loop=loop, loggers=loggers, proxy=proxy)
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self._aes_encrypt = None
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self._aes_decrypt = None
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def _write(self, data):
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self._writer.write(self._aes_encrypt.encrypt(data))
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async def _read(self, n):
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return self._aes_decrypt.encrypt(await self._reader.readexactly(n))
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async def connect(self, timeout=None, ssl=None):
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# FIXME: that's an abstraction leak
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await Connection.connect(self, timeout=timeout, ssl=ssl)
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# Obfuscated messages secrets cannot start with any of these
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keywords = (b'PVrG', b'GET ', b'POST', b'\xee\xee\xee\xee')
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while True:
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random = os.urandom(64)
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if (random[0] != 0xef and
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random[:4] not in keywords and
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random[4:4] != b'\0\0\0\0'):
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break
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random = bytearray(random)
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random[56] = random[57] = random[58] = random[59] = 0xef
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random_reversed = random[55:7:-1] # Reversed (8, len=48)
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# Encryption has "continuous buffer" enabled
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encrypt_key = self._compose_key(bytes(random[8:40]))
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encrypt_iv = bytes(random[40:56])
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decrypt_key = self._compose_key(bytes(random_reversed[:32]))
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decrypt_iv = bytes(random_reversed[32:48])
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self._aes_encrypt = AESModeCTR(encrypt_key, encrypt_iv)
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self._aes_decrypt = AESModeCTR(decrypt_key, decrypt_iv)
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random[56:64] = self._compose_tail(bytes(random))
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self._writer.write(random)
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await self._writer.drain()
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# Next functions provide the variable parts of the connection handshake.
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# This is necessary to modify obfuscated2 the way that MTProxy requires.
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def _compose_key(self, data):
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return data
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def _compose_tail(self, data):
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return self._aes_encrypt.encrypt(data)[56:64]
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