Re: [PATCH v3] crypto: des3_ede: permit weak keys unless REQ_WEAK_KEYset

From: Jarod Wilson
Date: Sat Dec 06 2008 - 00:44:58 EST

Jarod Wilson wrote:
While its a slightly insane to bypass the key1 == key2 ||
key2 == key3 check in triple-des, since it reduces it to the
same strength as des, some folks do need to do this from time
to time for backwards compatibility with des.

My own case is FIPS CAVS test vectors. Many triple-des test
vectors use a single key, replicated 3x. In order to get the
expected results, des3_ede_setkey() needs to honor the weak
key flag.

v2: make CRYPTO_TFM_REQ_WEAK_KEY flag usage consistent w/rest
of crypto subsystem, per comments from Herbert in Red Hat
bugzilla #474394.

v3: set more appropriate RES flag, also per Herbert.

Signed-off-by: Jarod Wilson <jarod@xxxxxxxxxx>

crypto/des_generic.c | 5 +++--
1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/crypto/des_generic.c b/crypto/des_generic.c
index 5d0e458..5bd3ee3 100644
--- a/crypto/des_generic.c
+++ b/crypto/des_generic.c
@@ -868,9 +868,10 @@ static int des3_ede_setkey(struct crypto_tfm *tfm, const u8 *key,
u32 *flags = &tfm->crt_flags;

if (unlikely(!((K[0] ^ K[2]) | (K[1] ^ K[3])) ||
- !((K[2] ^ K[4]) | (K[3] ^ K[5]))))
+ !((K[2] ^ K[4]) | (K[3] ^ K[5]))) &&
return -EINVAL;

Jarod Wilson

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