From f903da081b3eac3bc84a2e596591e7e634c3355d Mon Sep 17 00:00:00 2001 From: Paul Kehrer Date: Tue, 20 Mar 2018 13:33:57 -0400 Subject: fix bug with n % 8 length wrapping on AESKWP (#4160) * fix bug with n % 8 length wrapping on AESKWP * review feedback --- src/cryptography/hazmat/primitives/keywrap.py | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'src') diff --git a/src/cryptography/hazmat/primitives/keywrap.py b/src/cryptography/hazmat/primitives/keywrap.py index 3b531318..2b7955f8 100644 --- a/src/cryptography/hazmat/primitives/keywrap.py +++ b/src/cryptography/hazmat/primitives/keywrap.py @@ -118,11 +118,16 @@ def aes_key_unwrap_with_padding(wrapping_key, wrapped_key, backend): b = (8 * n) - mli if ( not bytes_eq(a[:4], b"\xa6\x59\x59\xa6") or not - 8 * (n - 1) < mli <= 8 * n or not bytes_eq(data[-b:], b"\x00" * b) + 8 * (n - 1) < mli <= 8 * n or ( + b != 0 and not bytes_eq(data[-b:], b"\x00" * b) + ) ): raise InvalidUnwrap() - return data[:-b] + if b == 0: + return data + else: + return data[:-b] def aes_key_unwrap(wrapping_key, wrapped_key, backend): -- cgit v1.2.3