#! /usr/bin/env python3

# MIT License
#
# Copyright (c) 2017 Bugfender
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

import hashlib
import sys

def check_hash(log, orig):
    # The log entry should be stored in the form of SALT:HASH
    salt, hash = log.split(":")
    salt = bytearray.fromhex(salt)

    new_hash = hashlib.pbkdf2_hmac("sha512", orig.encode("utf-8"), salt, 1000, dklen=64).hex()
    return new_hash == hash

if __name__ == "__main__":
    if len(sys.argv) != 3:
        print(sys.argv[0] + " SECRET LOG_ENTRY")
        sys.exit(1)

    if check_hash(sys.argv[2], sys.argv[1]):
        print("hash matches")
    else:
        print("hash doesn't match")