info.py

"""Extract info from config.bin"""

import argparse

import zcu


def print_payload_info(infile):
    """expects to be at the start of the payload magic"""

    # check magic
    header = infile.read(4)
    if header == b"BAMC":
        print(f"ERROR: {infile.name} is base64 encoded, please decode and try again.")
        return 1
    infile.seek(0)

    zcu.zte.read_header(infile)
    signature = zcu.zte.read_signature(infile)
    payload_header = zcu.zte.read_payload(infile)
    assert (
        payload_header[0] == zcu.constants.PAYLOAD_MAGIC
    ), "File does not begin with 0x01020304"
    payload_start = infile.tell()
    payload_type = payload_header[1]
    if payload_type == 0:
        payload_type_friendly = "(ZLIB)"
    elif payload_type == 1:
        payload_type_friendly = "(ZLIB+CRC)"
    elif payload_type == 2:
        payload_type_friendly = "(ZLIB+AES128ECB)"
    elif payload_type == 3:
        payload_type_friendly = "(ZLIB+AES256CBCSAMEIV)"
    elif payload_type == 4:
        payload_type_friendly = "(ZLIB+AES256CBCDIFFIV)"
    else:
        payload_type_friendly = "(UNKNOWN)"

    payload_length = payload_header[2]
    penultimate_chunk = payload_header[3]
    payload_chunk_size = payload_header[4]
    payload_crc = payload_header[5]
    payload_header_crc = payload_header[6]

    if len(signature) > 0:
        print("Signature:         ", signature.decode("utf-8"))

    print("Payload Type:      ", payload_type, payload_type_friendly)
    print("Payload Start:     ", payload_start)
    print("Decompressed size: ", payload_length, "bytes")
    print("2nd last chunk:    ", penultimate_chunk)
    print("Chunk size:        ", payload_chunk_size, "bytes")
    print("Payload CRC:       ", payload_crc)
    print("Header CRC:        ", payload_header_crc)


def main():
    """the main function"""
    parser = argparse.ArgumentParser(
        description="Read config.bin for ZTE Routers",
        formatter_class=argparse.RawDescriptionHelpFormatter,
    )
    parser.add_argument(
        "infile",
        type=argparse.FileType("rb"),
        help="Raw configuration file (config.xml)",
    )
    args = parser.parse_args()

    print_payload_info(args.infile)


if __name__ == "__main__":
    main()