From 2cc02255272160118dfe24d90bb6a7d844a0355a Mon Sep 17 00:00:00 2001 From: Thomas Waldmann Date: Tue, 15 Dec 2015 19:01:52 +0100 Subject: [PATCH] use hmac.compare_digest instead of == operator this is available in python 3.3+ --- borg/key.py | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/borg/key.py b/borg/key.py index 321158d1a..97a8dca54 100644 --- a/borg/key.py +++ b/borg/key.py @@ -4,7 +4,7 @@ import getpass import os import sys import textwrap -from hmac import HMAC +from hmac import HMAC, compare_digest from hashlib import sha256 from .helpers import IntegrityError, get_keys_dir, Error @@ -134,13 +134,17 @@ class AESKeyBase(KeyBase): def decrypt(self, id, data): if data[0] != self.TYPE: raise IntegrityError('Invalid encryption envelope') - hmac = memoryview(data)[1:33] - if memoryview(HMAC(self.enc_hmac_key, memoryview(data)[33:], sha256).digest()) != hmac: + hmac_given = memoryview(data)[1:33] + hmac_computed = memoryview(HMAC(self.enc_hmac_key, memoryview(data)[33:], sha256).digest()) + if not compare_digest(hmac_computed, hmac_given): raise IntegrityError('Encryption envelope checksum mismatch') self.dec_cipher.reset(iv=PREFIX + data[33:41]) data = self.compressor.decompress(self.dec_cipher.decrypt(data[41:])) - if id and HMAC(self.id_key, data, sha256).digest() != id: - raise IntegrityError('Chunk id verification failed') + if id: + hmac_given = id + hmac_computed = HMAC(self.id_key, data, sha256).digest() + if not compare_digest(hmac_computed, hmac_given): + raise IntegrityError('Chunk id verification failed') return data def extract_nonce(self, payload):