crypto: qat - Ensure ipad and opad are zeroed

Commit Message

Herbert Xu Jan. 13, 2015, 11:07 p.m. UTC

On Tue, Jan 13, 2015 at 02:55:24PM -0800, Tadeusz Struk wrote:
> On 01/13/2015 02:47 PM, Herbert Xu wrote:
> > Why are you allocating this qat_auth_state anyway? Just do
> > ipad/opad[block_size] and be done with it.
> 
> You are right. I don't need qat_auth_state really. Let me send you v2 in
> 2 mins.

Don't worry, I fixed it for you.

-- >8 --
The patch ad511e260a27b8e35d273cc0ecfe5a8ff9543181 (crypto: qat -
Fix incorrect uses of memzero_explicit) broke hashing because the
code was in fact overwriting the qat_auth_state variable.

In fact there is no reason for the variable to exist anyway since
all we are using it for is to store ipad and opad.  So we could
simply create ipad and opad directly and avoid this whole mess.

Signed-off-by: Herbert Xu <[e-mail]>


Cheers,

Comments

Tadeusz Struk Jan. 13, 2015, 11:20 p.m. UTC | #1

On 01/13/2015 03:07 PM, Herbert Xu wrote:
> The patch ad511e260a27b8e35d273cc0ecfe5a8ff9543181 (crypto: qat -
> Fix incorrect uses of memzero_explicit) broke hashing because the
> code was in fact overwriting the qat_auth_state variable.
> 
> In fact there is no reason for the variable to exist anyway since
> all we are using it for is to store ipad and opad.  So we could
> simply create ipad and opad directly and avoid this whole mess.
> 
> Signed-off-by: Herbert Xu <[e-mail]>

Ok that looks better. Thanks. I think we should also remove the
definition of struct qat_auth_state in line 107 and the #def above.
Regards,
Tadeusz
--
To unsubscribe from this list: send the line "unsubscribe linux-crypto" in
the body of a message to [e-mail]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Patch

diff --git a/drivers/crypto/qat/qat_common/qat_algs.c b/drivers/crypto/qat/qat_common/qat_algs.c
index a0d95f3..e2c4b25 100644
--- a/drivers/crypto/qat/qat_common/qat_algs.c
+++ b/drivers/crypto/qat/qat_common/qat_algs.c
@@ -160,33 +160,30 @@  static int qat_alg_do_precomputes(struct icp_qat_hw_auth_algo_blk *hash,
 				  const uint8_t *auth_key,
 				  unsigned int auth_keylen)
 {
-	struct qat_auth_state auth_state;
 	SHASH_DESC_ON_STACK(shash, ctx->hash_tfm);
 	struct sha1_state sha1;
 	struct sha256_state sha256;
 	struct sha512_state sha512;
 	int block_size = crypto_shash_blocksize(ctx->hash_tfm);
 	int digest_size = crypto_shash_digestsize(ctx->hash_tfm);
-	uint8_t *ipad = auth_state.data;
-	uint8_t *opad = ipad + block_size;
+	char ipad[block_size];
+	char opad[block_size];
 	__be32 *hash_state_out;
 	__be64 *hash512_state_out;
 	int i, offset;
 
-	memset(auth_state.data, 0, sizeof(auth_state.data));
+	memset(ipad, 0, block_size);
+	memset(opad, 0, block_size);
 	shash->tfm = ctx->hash_tfm;
 	shash->flags = 0x0;
 
 	if (auth_keylen > block_size) {
-		char buff[SHA512_BLOCK_SIZE];
 		int ret = crypto_shash_digest(shash, auth_key,
-					      auth_keylen, buff);
+					      auth_keylen, ipad);
 		if (ret)
 			return ret;
 
-		memcpy(ipad, buff, digest_size);
-		memcpy(opad, buff, digest_size);
-		memzero_explicit(buff, sizeof(buff));
+		memcpy(opad, ipad, digest_size);
 	} else {
 		memcpy(ipad, auth_key, auth_keylen);
 		memcpy(opad, auth_key, auth_keylen);