From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756660Ab1HXLMH (ORCPT ); Wed, 24 Aug 2011 07:12:07 -0400 Received: from mail-yx0-f174.google.com ([209.85.213.174]:42358 "EHLO mail-yx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751657Ab1HXLMF convert rfc822-to-8bit (ORCPT ); Wed, 24 Aug 2011 07:12:05 -0400 MIME-Version: 1.0 In-Reply-To: <20110824110826.GD23757@pulham.picochip.com> References: <1314183181-4197-1-git-send-email-jason.hui@linaro.org> <20110824110826.GD23757@pulham.picochip.com> Date: Wed, 24 Aug 2011 19:12:05 +0800 Message-ID: Subject: Re: [PATCH] mtd: check parts pointer before using it From: Jason Liu To: Jamie Iles Cc: Jason Liu , 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 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2011/8/24 Jamie Iles : > 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. My bad, I type it error. Thanks for it. > >>               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. Yes, correct. Thanks, > > Jamie > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at  http://vger.kernel.org/majordomo-info.html > Please read the FAQ at  http://www.tux.org/lkml/ >