From 674f368a952c48ede71784935a799a5205b92b6c Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Mon, 30 Dec 2019 21:19:36 -0600 Subject: crypto: remove CRYPTO_TFM_RES_BAD_KEY_LEN MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The CRYPTO_TFM_RES_BAD_KEY_LEN flag was apparently meant as a way to make the ->setkey() functions provide more information about errors. However, no one actually checks for this flag, which makes it pointless. Also, many algorithms fail to set this flag when given a bad length key. Reviewing just the generic implementations, this is the case for aes-fixed-time, cbcmac, echainiv, nhpoly1305, pcrypt, rfc3686, rfc4309, rfc7539, rfc7539esp, salsa20, seqiv, and xcbc. But there are probably many more in arch/*/crypto/ and drivers/crypto/. Some algorithms can even set this flag when the key is the correct length. For example, authenc and authencesn set it when the key payload is malformed in any way (not just a bad length), the atmel-sha and ccree drivers can set it if a memory allocation fails, and the chelsio driver sets it for bad auth tag lengths, not just bad key lengths. So even if someone actually wanted to start checking this flag (which seems unlikely, since it's been unused for a long time), there would be a lot of work needed to get it working correctly. But it would probably be much better to go back to the drawing board and just define different return values, like -EINVAL if the key is invalid for the algorithm vs. -EKEYREJECTED if the key was rejected by a policy like "no weak keys". That would be much simpler, less error-prone, and easier to test. So just remove this flag. Signed-off-by: Eric Biggers Reviewed-by: Horia Geantă Signed-off-by: Herbert Xu --- crypto/skcipher.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'crypto/skcipher.c') diff --git a/crypto/skcipher.c b/crypto/skcipher.c index 457e4ddc1482..8c8735f75478 100644 --- a/crypto/skcipher.c +++ b/crypto/skcipher.c @@ -603,10 +603,8 @@ int crypto_skcipher_setkey(struct crypto_skcipher *tfm, const u8 *key, unsigned long alignmask = crypto_skcipher_alignmask(tfm); int err; - if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) { - crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN); + if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) return -EINVAL; - } if ((unsigned long)key & alignmask) err = skcipher_setkey_unaligned(tfm, key, keylen); -- cgit v1.2.3-70-g09d2