From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1755521AbaEOW6q (ORCPT <rfc822;w@1wt.eu>);
	Thu, 15 May 2014 18:58:46 -0400
Received: from mail.linuxfoundation.org ([140.211.169.12]:39462 "EHLO
	mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1752291AbaEOW6p (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Thu, 15 May 2014 18:58:45 -0400
Date: Thu, 15 May 2014 15:58:44 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Joe Perches <joe@perches.com>
Cc: Andy Whitcroft <apw@canonical.com>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] checkpatch: Add --strict test for kmalloc/kzalloc with
 multiply
Message-Id: <20140515155844.041ee0bc17aae5f3b8eacd70@linux-foundation.org>
In-Reply-To: <1400024929.24350.76.camel@joe-AO725>
References: <1400024929.24350.76.camel@joe-AO725>
X-Mailer: Sylpheed 3.2.0beta5 (GTK+ 2.24.10; x86_64-pc-linux-gnu)
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Tue, 13 May 2014 16:48:49 -0700 Joe Perches <joe@perches.com> wrote:

> Protect against sizeof overflows by preferring
> kmalloc_array and kcalloc to kmalloc/kzalloc
> with a sizeof multiply.
> 
> ...
>
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -4378,6 +4378,20 @@ sub process {
>  			    "Prefer $3(sizeof(*$1)...) over $3($4...)\n" . $herecurr);
>  		}
>  
> +# check for k[mz]alloc with multiplies that could be kmalloc_array/kcalloc
> +		if ($^V && $^V ge 5.10.0 &&
> +		    $line =~ /\b($Lval)\s*\=\s*(?:$balanced_parens)?\s*(k[mz]alloc)\s*\(\s*($FuncArg)\s*\*\s*($FuncArg)/) {
> +			my $oldfunc = $3;
> +			my $a1 = $4;
> +			my $a2 = $10;
> +			my $newfunc = "kmalloc_array";
> +			$newfunc = "kcalloc" if ($oldfunc eq "kzalloc");
> +			if ($a1 =~ /^sizeof\s*\S/ || $a2 =~ /^sizeof\s*\S/) {
> +				CHK("ALLOC_WITH_MULTIPLY",
> +				    "Prefer $newfunc over $oldfunc with multiply\n" . $herecurr);
> +			}
> +		}
> +

Why hide this behind --strict?