From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756441Ab1HXLIk (ORCPT ); Wed, 24 Aug 2011 07:08:40 -0400 Received: from mail-ww0-f42.google.com ([74.125.82.42]:60387 "EHLO mail-ww0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751395Ab1HXLIj (ORCPT ); Wed, 24 Aug 2011 07:08:39 -0400 Date: Wed, 24 Aug 2011 12:08:26 +0100 From: Jamie Iles To: Jason Liu Cc: linux-arm-kernel@lists.infradead.org, dedekind1@gmail.com, linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, patches@linaro.org, David.Woodhouse@intel.com Subject: Re: [PATCH] mtd: check parts pointer before using it Message-ID: <20110824110826.GD23757@pulham.picochip.com> References: <1314183181-4197-1-git-send-email-jason.hui@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1314183181-4197-1-git-send-email-jason.hui@linaro.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jason, On Wed, Aug 24, 2011 at 06:53:01PM +0800, Jason Liu wrote: > The code has the check for parts but it called after kmemdup, > kmemdup(parts, sizeof(*parts) * nr_parts,...) > if (!parts) > return -ENOMEM > > In fact, we need check parts before safely using it. > > Signed-off-by: Jason Liu > Cc: Dmitry Eremin-Solenikov > Cc: Artem Bityutskiy > > --- > This patch is based on git://git.infradead.org/users/dedekind/l2-mtd-2.6.git > --- > drivers/mtd/mtdcore.c | 4 +--- > 1 files changed, 1 insertions(+), 3 deletions(-) > > diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c > index 09bdbac..ce59ff5 100644 > --- a/drivers/mtd/mtdcore.c > +++ b/drivers/mtd/mtdcore.c > @@ -465,12 +465,10 @@ int mtd_device_parse_register(struct mtd_info *mtd, const char **types, > struct mtd_partition *real_parts; > > err = parse_mtd_partitions(mtd, types, &real_parts, parser_data); > - if (err <= 0 && nr_parts) { > + if (err <= 0 && nr_parts && !parts) { I don't think this is right. Don't we want to check that parts is != NULL? So if (err <= 0 && nr_parts && parts) instead? We don't want to kmemdup() NULL. > real_parts = kmemdup(parts, sizeof(*parts) * nr_parts, > GFP_KERNEL); > err = nr_parts; > - if (!parts) > - err = -ENOMEM; I think this hunk should be changed to: if (!real_parts) err = -ENOMEM; and keep the check so that we're checking kmemdup()'s allocation is successful. Jamie