diff options
| -rw-r--r-- | cryptography/hazmat/primitives/padding.py | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/cryptography/hazmat/primitives/padding.py b/cryptography/hazmat/primitives/padding.py index 86ea26e3..ddcadd89 100644 --- a/cryptography/hazmat/primitives/padding.py +++ b/cryptography/hazmat/primitives/padding.py @@ -109,9 +109,12 @@ class _PKCS7UnpaddingContext(object): if pad_size > self.block_size // 8: raise ValueError("Invalid padding bytes") + mismatch = 0 for b in six.iterbytes(self._buffer[-pad_size:]): - if b != pad_size: - raise ValueError("Invalid padding bytes") + mismatch |= b ^ pad_size + + if mismatch != 0: + raise ValueError("Invalid padding bytes") res = self._buffer[:-pad_size] self._buffer = None |