From: Steffen Klassert <steffen.klassert@secunet.com>
Subject: Re: crypto: user - Allow get request with empty driver name
Date: Thu, 20 Nov 2014 08:11:42 +0100
Message-ID: <20141120071141.GS6390@secunet.com>
References: <5365136.g8vbXlhRyC@tachyon.chronox.de>
 <1886827.KUDIsNtfuk@tachyon.chronox.de>
 <20141120041824.GA28612@gondor.apana.org.au>
 <3538055.XH2t7HNEVj@tachyon.chronox.de>
 <20141120044650.GA28691@gondor.apana.org.au>
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Cc: Stephan Mueller <smueller@chronox.de>,
	Daniel Borkmann <dborkman@redhat.com>,
	<quentin.gouchet@gmail.com>, LKML <linux-kernel@vger.kernel.org>,
	<linux-crypto@vger.kernel.org>, ABI/API <linux-api@vger.kernel.org>
To: Herbert Xu <herbert@gondor.apana.org.au>
Return-path: <linux-kernel-owner@vger.kernel.org>
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In-Reply-To: <20141120044650.GA28691@gondor.apana.org.au>
Sender: linux-kernel-owner@vger.kernel.org
List-Id: linux-crypto.vger.kernel.org

On Thu, Nov 20, 2014 at 12:46:50PM +0800, Herbert Xu wrote:
> On Thu, Nov 20, 2014 at 05:23:23AM +0100, Stephan Mueller wrote:
> > 
> > Here is the code:
> > 
> > static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
> > 			 struct nlattr **attrs)
> > {
> > ...
> > 	if (!p->cru_driver_name[0])
> > 		return -EINVAL;
> 
> OK let's fix this.
> 
> crypto: user - Allow get request with empty driver name
>     
> Currently all get requests with an empty driver name fail with
> EINVAL.  Since most users actually want to supply an empty driver
> name this patch removes this check.
> 
> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
> 
> diff --git a/crypto/crypto_user.c b/crypto/crypto_user.c
> index e2a34fe..0bb30ac 100644
> --- a/crypto/crypto_user.c
> +++ b/crypto/crypto_user.c
> @@ -201,10 +201,7 @@ static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
>  	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
>  		return -EINVAL;
>  
> -	if (!p->cru_driver_name[0])
> -		return -EINVAL;
> -
> -	alg = crypto_alg_match(p, 1);
> +	alg = crypto_alg_match(p, 0);

I think this is not sufficient, crypto_alg_match() will now return the first
algorithm in crypto_alg_list that matches cra_name. We would need to extend
crypto_alg_match() to return the algorithm with the highest priority in that
case.