From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753460AbdKIIbr (ORCPT ); Thu, 9 Nov 2017 03:31:47 -0500 Received: from mail-wm0-f68.google.com ([74.125.82.68]:33351 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753275AbdKIIbp (ORCPT ); Thu, 9 Nov 2017 03:31:45 -0500 X-Google-Smtp-Source: ABhQp+R+hYiDwVrWXH8dTrjr3zm1bmr9E7IVx740/RDziSDG7hAcIxSSNiZbn9ZPkYvG5xzq8csyRg== Date: Thu, 9 Nov 2017 09:31:41 +0100 From: Pali =?utf-8?B?Um9ow6Fy?= To: Arnd Bergmann Cc: Mario Limonciello , Darren Hart , Andy Shevchenko , "Edward O'Callaghan" , Hans de Goede , platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] dell-smbios: fix string overflow Message-ID: <20171109083141.g4fvxsuoprwlkud3@pali> References: <20171108120844.3196747-1-arnd@arndb.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20171108120844.3196747-1-arnd@arndb.de> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday 08 November 2017 13:08:39 Arnd Bergmann wrote: > The new sysfs code overwrites two fixed-length character arrays > that are each one byte shorter than they need to be, to hold > the trailing \0: > > drivers/platform/x86/dell-smbios.c: In function 'build_tokens_sysfs': > drivers/platform/x86/dell-smbios.c:494:42: error: 'sprintf' writing a terminating nul past the end of the destination [-Werror=format-overflow=] > sprintf(buffer_location, "%04x_location", > drivers/platform/x86/dell-smbios.c:494:3: note: 'sprintf' output 14 bytes into a destination of size 13 > drivers/platform/x86/dell-smbios.c:506:36: error: 'sprintf' writing a terminating nul past the end of the destination [-Werror=format-overflow=] > sprintf(buffer_value, "%04x_value", > drivers/platform/x86/dell-smbios.c:506:3: note: 'sprintf' output 11 bytes into a destination of size 10 > > This changes it to just use kasprintf(), which always gets it right. > > Fixes: 33b9ca1e53b4 ("platform/x86: dell-smbios: Add a sysfs interface for SMBIOS tokens") > Signed-off-by: Arnd Bergmann Reviewed-by: Pali Rohár > --- > drivers/platform/x86/dell-smbios.c | 12 ++++-------- > 1 file changed, 4 insertions(+), 8 deletions(-) > > diff --git a/drivers/platform/x86/dell-smbios.c b/drivers/platform/x86/dell-smbios.c > index d99edd803c19..6a60db515bda 100644 > --- a/drivers/platform/x86/dell-smbios.c > +++ b/drivers/platform/x86/dell-smbios.c > @@ -463,8 +463,6 @@ static struct platform_driver platform_driver = { > > static int build_tokens_sysfs(struct platform_device *dev) > { > - char buffer_location[13]; > - char buffer_value[10]; > char *location_name; > char *value_name; > size_t size; > @@ -491,9 +489,8 @@ static int build_tokens_sysfs(struct platform_device *dev) > if (da_tokens[i].tokenID == 0) > continue; > /* add location */ > - sprintf(buffer_location, "%04x_location", > - da_tokens[i].tokenID); > - location_name = kstrdup(buffer_location, GFP_KERNEL); > + location_name = kasprintf(GFP_KERNEL, "%04x_location", > + da_tokens[i].tokenID); > if (location_name == NULL) > goto out_unwind_strings; > sysfs_attr_init(&token_location_attrs[i].attr); > @@ -503,9 +500,8 @@ static int build_tokens_sysfs(struct platform_device *dev) > token_attrs[j++] = &token_location_attrs[i].attr; > > /* add value */ > - sprintf(buffer_value, "%04x_value", > - da_tokens[i].tokenID); > - value_name = kstrdup(buffer_value, GFP_KERNEL); > + value_name = kasprintf(GFP_KERNEL, "%04x_value", > + da_tokens[i].tokenID); > if (value_name == NULL) > goto loop_fail_create_value; > sysfs_attr_init(&token_value_attrs[i].attr); -- Pali Rohár pali.rohar@gmail.com