181 lines
7.2 KiB
Python
181 lines
7.2 KiB
Python
import base64
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import json
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import logging
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from json.encoder import encode_basestring_ascii
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from typing import Literal
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from uuid import UUID
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from pathlib import Path
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def bytes2int(value: bytes, byteorder: Literal["big", "little"] = "big", signed: bool = False) -> int:
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"""
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Convert a byte sequence to an integer.
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Parameters:
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value (bytes): The byte sequence to convert.
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byteorder (str, optional): Byte order for conversion. 'big' or 'little'. Defaults to 'big'.
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signed (bool, optional): Whether the integer is signed. Defaults to False.
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Returns:
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int: The integer representation of the byte sequence.
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"""
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return int.from_bytes(value, byteorder=byteorder, signed=signed)
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class Keybox:
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"""
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The Keybox class handles the storage and management of device IDs and keybox data.
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"""
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def __init__(self):
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"""
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Initializes the Keybox object, setting up logger and containers for device IDs and keyboxes.
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"""
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self.logger = logging.getLogger(self.__class__.__name__)
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# https://github.com/kaltura/kaltura-device-info-android/blob/master/app/src/main/java/com/kaltura/kalturadeviceinfo/MainActivity.java#L203
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self.device_id = []
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self.keybox = {}
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def set_device_id(self, data: bytes) -> None:
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"""
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Set the device ID from the provided data.
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Parameters:
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data (bytes): The device ID, expected to be 32 bytes long.
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Raises:
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AssertionError: If the data length is not 32 bytes.
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"""
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try:
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size = len(data)
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# Ensure the device ID is exactly 32 bytes long
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assert size == 32, f"Invalid device ID length: {size}. Should be 32 bytes"
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# Add device ID to the list if it's not already present
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if data not in self.device_id:
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self.logger.info("Receive device id: \n\n%s\n", encode_basestring_ascii(data.decode("utf-8")))
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self.device_id.append(data)
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except Exception as e:
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self.logger.debug("Failed to set device id: %s", e)
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def set_keybox(self, data: bytes) -> None:
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"""
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Set the keybox from the provided data.
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Parameters:
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data (bytes): The keybox data, expected to be either 128 or 132 bytes long.
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Raises:
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AssertionError: If the data length is not 128 or 132 bytes or does not meet other criteria.
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"""
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# https://github.com/zybpp/Python/tree/master/Python/keybox
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try:
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size = len(data)
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# Validate the keybox size (128 or 132 bytes)
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assert size in (128, 132), f"Invalid keybox length: {size}. Should be 128 or 132 bytes"
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# Validate the QSEE-style keybox end
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assert size == 128 or data[128:132] == b"LVL1", "QSEE-style keybox must end with bytes 'LVL1'"
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# Validate the keybox magic (should be 'kbox')
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assert data[120:124] == b"kbox", "Invalid keybox magic"
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device_id = data[0:32] # Extract the device ID from the first 32 bytes
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# Retrieve and log the structured keybox information
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infos = self.__keybox_info(data)
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encrypted = infos["flags"] > 10 # Check if the keybox is encrypted
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self.set_device_id(data=device_id) # Set the device ID
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# Log and store the keybox data if it's a new keybox or the device ID is updated
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if (device_id in self.keybox and self.keybox[device_id] != (data, encrypted)) or device_id not in self.keybox:
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self.logger.info("Receive keybox: \n\n%s\n", json.dumps(infos, indent=2))
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# Warn if keybox is encrypted and interception of plaintext device token is needed
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if encrypted:
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self.logger.warning("Keybox contains encrypted data. Interception of plaintext device token is needed")
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# Store the keybox (encrypted or not) for the device ID
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if (device_id in self.keybox and not encrypted) or device_id not in self.keybox:
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self.keybox[device_id] = (data, encrypted)
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except Exception as e:
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self.logger.debug("Failed to set keybox: %s", e)
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@staticmethod
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def __keybox_info(data: bytes) -> dict:
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"""
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Extract keybox information from the provided data.
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Parameters:
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data (bytes): The keybox data.
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Returns:
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dict: A dictionary containing extracted keybox information.
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"""
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# https://github.com/wvdumper/dumper/blob/main/Helpers/Keybox.py#L51
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# Extract device-specific information from the keybox data
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device_token = data[48:120]
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# Prepare the keybox content dictionary
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content = {
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"device_id": data[0:32].decode("utf-8"), # Device's unique identifier (32 bytes)
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"device_key": data[32:48], # Device cryptographic key (16 bytes)
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"device_token": device_token, # Token for device authentication (72 bytes)
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"keybox_tag": data[120:124].decode("utf-8"), # Magic tag (4 bytes)
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"crc32": bytes2int(data[124:128]), # CRC32 checksum (4 bytes)
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"level_tag": data[128:132].decode("utf-8") or None, # Optional level tag (4 bytes)
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# Extract metadata from the device token (Bytes 48–120)
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"flags": bytes2int(device_token[0:4]), # Device flags (4 bytes)
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"system_id": bytes2int(device_token[4:8]), # System identifier (4 bytes)
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"provisioning_id": UUID(bytes_le=device_token[8:24]), # Provisioning UUID (16 bytes)
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"encrypted_bits": device_token[24:72] # Encrypted device-specific information (48 bytes)
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}
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# https://github.com/ThatNotEasy/Parser-DRM/blob/main/modules/widevine.py#L84
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# TODO: decrypt device token value
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# Encode bytes as base64 and convert UUIDs to string
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return {
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k: base64.b64encode(v).decode("utf-8") if isinstance(v, bytes) else str(v) if isinstance(v, UUID) else v
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for k, v in content.items()
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}
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def export(self, parent: Path) -> bool:
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"""
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Export the keybox data to a file in the specified parent directory.
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Parameters:
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parent (Path): The parent directory where the keybox data will be saved.
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Returns:
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bool: True if any keybox were exported, otherwise False.
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"""
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# Find matching keyboxes based on the device_id
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keys = self.device_id & self.keybox.keys()
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for k in keys:
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# Create the parent directory if it doesn't exist
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parent.mkdir(parents=True, exist_ok=True)
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# Define the export file path and extension (encrypted or binary)
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path_keybox_bin = parent / ("keybox." + ("enc" if self.keybox[k][1] else "bin"))
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# Write the keybox data to the file
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path_keybox_bin.write_bytes(self.keybox[k][0])
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# Log export status based on whether the keybox is encrypted
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if self.keybox[k][1]:
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self.logger.warning("Exported encrypted keybox: %s", path_keybox_bin)
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else:
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self.logger.info("Exported keybox: %s", path_keybox_bin)
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# Return True if any keyboxes were exported, otherwise False
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return len(keys) > 0
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__all__ = ("Keybox",)
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