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authorRob Austein <sra@hactrn.net>2017-06-02 12:26:10 -0400
committerRob Austein <sra@hactrn.net>2017-06-02 12:26:10 -0400
commit6a47490407210471afdd80f009123bd72014db3a (patch)
treeb1034e6bdab9cdd3b66ea8d2ee0b1c67b76b32cb /unit-tests.py
parent35a88083a9936b2ed3d0091c0461530be81287c1 (diff)
Fix AESKeywrapWithPadding handling of very long messages.
We were XORing the low 32 bits of R[0] instead of the full 64 bits. Makes no difference for small values of n, so we never detected it.
Diffstat (limited to 'unit-tests.py')
-rw-r--r--unit-tests.py12
1 files changed, 6 insertions, 6 deletions
diff --git a/unit-tests.py b/unit-tests.py
index 9ebf91e..8b86d44 100644
--- a/unit-tests.py
+++ b/unit-tests.py
@@ -1035,6 +1035,10 @@ class AESKeyWrapWithPadding(object):
step = -1 if start > stop else 1
return xrange(start, stop + step, step)
+ @staticmethod
+ def _xor(R0, t):
+ return pack(">Q", unpack(">Q", R0)[0] ^ t)
+
def wrap(self, Q):
"RFC 5649 section 4.1."
m = len(Q) # Plaintext length
@@ -1051,9 +1055,7 @@ class AESKeyWrapWithPadding(object):
for j in self._start_stop(0, 5):
for i in self._start_stop(1, n):
R[0], R[i] = self._encrypt(R[0], R[i])
- W0, W1 = unpack(">LL", R[0])
- W1 ^= n * j + i
- R[0] = pack(">LL", W0, W1)
+ R[0] = self._xor(R[0], n * j + i)
assert len(R) == (n + 1) and all(len(r) == 8 for r in R)
return "".join(R)
@@ -1070,9 +1072,7 @@ class AESKeyWrapWithPadding(object):
# RFC 3394 section 2.2.2 steps (1), (2), and part of (3)
for j in self._start_stop(5, 0):
for i in self._start_stop(n, 1):
- W0, W1 = unpack(">LL", R[0])
- W1 ^= n * j + i
- R[0] = pack(">LL", W0, W1)
+ R[0] = self._xor(R[0], n * j + i)
R[0], R[i] = self._decrypt(R[0], R[i])
magic, m = unpack(">LL", R[0])
if magic != 0xa65959a6: