From: Herbert Xu Subject: Re: [PATCH 1/1] crypto: If two strings are exact match, they must have same length. Date: Wed, 22 Mar 2017 11:00:40 +0800 Message-ID: <20170322030040.GB29214@gondor.apana.org.au> References: <1490132440-112761-1-git-send-email-mingma@micron.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: davem@davemloft.net, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org To: Ming Ma Return-path: Received: from helcar.hengli.com.au ([209.40.204.226]:46403 "EHLO helcar.apana.org.au" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751192AbdCVDBA (ORCPT ); Tue, 21 Mar 2017 23:01:00 -0400 Content-Disposition: inline In-Reply-To: <1490132440-112761-1-git-send-email-mingma@micron.com> Sender: linux-crypto-owner@vger.kernel.org List-ID: On Tue, Mar 21, 2017 at 04:40:40PM -0500, Ming Ma wrote: > When both "crct10dif-pclmul" algorithm and "crct10dif-generic" algorithm > exist in crypto_alg_list, "crct10dif-pclmul" should be selected, since it > has higher priority than "crct10dif-generic". However, both algorithms > have the same cra_name "crct10dif". If we use "crct10dif" to find a > matched algorithm in crypto_alg_list, it's possible "crct10dif-generic" is > selected, because the code calls strcmp to decide if two string are exact > match, but doesn't check if two strings have the same length. > > exact = !strcmp(q->cra_driver_name, name); > > So ,if "crct10dif-generic" is in front of "crct10dif-pclmul" in > crypto_alg_list, it will be picked as the matched algorithm, even if it has > lower priority than "crct10dif-pclmul". > Signed-off-by: Ming Ma > --- > crypto/api.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/crypto/api.c b/crypto/api.c > index b16ce16..5b3d45a 100644 > --- a/crypto/api.c > +++ b/crypto/api.c > @@ -76,7 +76,8 @@ static struct crypto_alg *__crypto_alg_lookup(const char *name, u32 type, > ((struct crypto_larval *)q)->mask != mask) > continue; > > - exact = !strcmp(q->cra_driver_name, name); > + exact = (strlen(name) == strlen(q->cra_driver_name)) && > + !strcmp(q->cra_driver_name, name); > fuzzy = !strcmp(q->cra_name, name); > if (!exact && !(fuzzy && q->cra_priority > best)) > continue; This is bogus. Please describe how you reproduced the problem. The priority matching should work. Cheers, -- Email: Herbert Xu Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt