From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 1/15] don't reallocate buffer in every audit_sockaddr()
Date: Tue, 16 Dec 2008 23:49:27 -0800
Message-ID: <20081216234927.9cb8a077.akpm@linux-foundation.org>
References: <E1LCogg-00008b-SH@ZenIV.linux.org.uk>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Return-path: <linux-audit-bounces@redhat.com>
Received: from mx3.redhat.com (mx3.redhat.com [172.16.48.32])
	by int-mx1.corp.redhat.com (8.13.1/8.13.1) with ESMTP id mBH7oC0a000811
	for <linux-audit@redhat.com>; Wed, 17 Dec 2008 02:50:12 -0500
Received: from smtp1.linux-foundation.org (smtp1.linux-foundation.org
	[140.211.169.13])
	by mx3.redhat.com (8.13.8/8.13.8) with ESMTP id mBH7o0oe008237
	for <linux-audit@redhat.com>; Wed, 17 Dec 2008 02:50:01 -0500
In-Reply-To: <E1LCogg-00008b-SH@ZenIV.linux.org.uk>
List-Unsubscribe: <https://www.redhat.com/mailman/listinfo/linux-audit>,
	<mailto:linux-audit-request@redhat.com?subject=unsubscribe>
List-Archive: <https://www.redhat.com/archives/linux-audit>
List-Post: <mailto:linux-audit@redhat.com>
List-Help: <mailto:linux-audit-request@redhat.com?subject=help>
List-Subscribe: <https://www.redhat.com/mailman/listinfo/linux-audit>,
	<mailto:linux-audit-request@redhat.com?subject=subscribe>
Sender: linux-audit-bounces@redhat.com
Errors-To: linux-audit-bounces@redhat.com
To: Al Viro <viro@ftp.linux.org.uk>
Cc: linux-audit@redhat.com, linux-kernel@vger.kernel.org
List-Id: linux-audit@redhat.com

On Wed, 17 Dec 2008 05:11:10 +0000 Al Viro <viro@ftp.linux.org.uk> wrote:

>  int audit_sockaddr(int len, void *a)
>  {
> -	struct audit_aux_data_sockaddr *ax;
>  	struct audit_context *context = current->audit_context;
>  
>  	if (likely(!context || context->dummy))
>  		return 0;
>  
> -	ax = kmalloc(sizeof(*ax) + len, GFP_KERNEL);
> -	if (!ax)
> -		return -ENOMEM;
> -
> -	ax->len = len;
> -	memcpy(ax->a, a, len);
> +	if (!context->sockaddr) {
> +		void *p = kmalloc(sizeof(struct sockaddr_storage), GFP_KERNEL);

argh, I really hate having to run all around the code verifying that
the type passed to sizeof matches the type that we'll be storing there :(


> +		if (!p)
> +			return -ENOMEM;
> +		context->sockaddr = p;
> +	}
>  
> -	ax->d.type = AUDIT_SOCKADDR;
> -	ax->d.next = context->aux;
> -	context->aux = (void *)ax;
> +	context->sockaddr_len = len;
> +	memcpy(context->sockaddr, a, len);
>  	return 0;
>  }

stoopid question: can an audit_contect be shared between
threads/processes?  If so, is locking needed around the read/test/write
of context->sockaddr and friends?