kakaotalk_analysis/scripts/mitmproxy/lib/loco_packet.py
2023-12-26 17:16:28 +01:00

121 lines
3.8 KiB
Python

import io
import logging
import struct
import bson
from lib.crypto_utils import aes_encrypt
class LocoPacket:
def __init__(
self,
identifier=0,
status_code=0,
loco_command="",
body_type=0,
body_length=0,
body_payload=b"",
):
self.id = identifier
self.status_code = status_code
self.loco_command = loco_command
self.body_type = body_type
self.body_length = body_length
self.body_payload = body_payload
def get_packet_bytes(self) -> bytes:
try:
f = io.BytesIO()
f.write(struct.pack("<I", self.id))
f.write(struct.pack("<H", self.status_code))
f.write(self.loco_command.encode("utf-8"))
f.write(b"\x00" * (11 - len(self.loco_command)))
f.write(struct.pack("<b", self.body_type))
f.write(struct.pack("<i", self.body_length))
f.write(self.body_payload)
return f.getvalue()
except Exception as general_exception:
logging.error("Could not create LOCO packet: %s", general_exception)
return None
def get_packet_as_dict(self) -> dict:
loco_dict = vars(self)
try:
if loco_dict["body_payload"] and isinstance(
loco_dict["body_payload"], bytes
):
loco_dict["body_payload"] = bson.loads(self.body_payload)
elif loco_dict["body_payload"] and isinstance(
loco_dict["body_payload"], dict
):
loco_dict["body_payload"] = self.body_payload
except Exception as general_exception:
loco_dict = {}
logging.error(
"Couldn't decode BSON body of %s packet. Exception: %s.",
self.loco_command,
general_exception,
)
return loco_dict
class LocoEncryptedPacket:
def __init__(self, length=0, iv=b"", payload=b"", is_fragmented=False):
self.length = length
self.iv = iv
self.payload = payload
self.is_fragmented = is_fragmented
def create_new_packet(self, loco_packet: LocoPacket) -> bytes:
if not loco_packet:
logging.error(
"Could not create LOCO encrypted packet: LOCO packet data is None."
)
return None
encrypted_packet = aes_encrypt(loco_packet.get_packet_bytes(), self.iv)
if not encrypted_packet:
logging.error("Could not encrypt LOCO packet.")
return None
try:
f = io.BytesIO()
f.write(struct.pack("<I", len(encrypted_packet) + len(self.iv)))
f.write(self.iv)
f.write(encrypted_packet)
return f.getvalue()
except Exception as general_exception:
logging.error(
"Could not create LOCO encrypted packet: %s", general_exception
)
return None
def get_packet_bytes(self) -> bytes:
try:
f = io.BytesIO()
f.write(struct.pack("<I", len(self.payload) + len(self.iv)))
f.write(self.iv)
f.write(self.payload)
return f.getvalue()
except Exception as general_exception:
logging.error(
"Could not convert LOCO encrypted packet to bytes: %s",
general_exception,
)
return None
class LocoHandshakePacket:
def __init__(self, length=256, handshake_type=0, block_cipher_mode=0, payload=b""):
self.length = length
self.type = handshake_type
self.block_cipher_mode = block_cipher_mode
self.payload = payload
self.cipher_mode_map = {1: "CBC", 2: "AES/CFB/NoPadding", 3: "OFB"}
self.encryption_mode_map = {15: "RSA/NONE/OAEPWithSHA1AndMGF1Padding"}