From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 76015C2BA2B for ; Mon, 13 Apr 2020 16:30:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 541A8206DA for ; Mon, 13 Apr 2020 16:30:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731598AbgDMQao (ORCPT ); Mon, 13 Apr 2020 12:30:44 -0400 Received: from mga12.intel.com ([192.55.52.136]:5348 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731587AbgDMQam (ORCPT ); Mon, 13 Apr 2020 12:30:42 -0400 IronPort-SDR: 0UjSJ/RMfCiNIX0Hh3JAdOmfgE0+nvpvGr9R1lCZzMTkujWXkRbXhHGq7f+xKllFwPbD+NdFmR YrQ68/LQiEnQ== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Apr 2020 09:30:42 -0700 IronPort-SDR: YrPaTfiJBoTLNJE0b55d6fX275Obm/Ipg/2Y6SdKePOLQjN8gmg8/wMGZv8V3anyfg+1V056T+ 3SYUxrodWw1Q== X-IronPort-AV: E=Sophos;i="5.72,378,1580803200"; d="scan'208";a="256226157" Received: from rchatre-mobl.amr.corp.intel.com (HELO [10.254.108.87]) ([10.254.108.87]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Apr 2020 09:30:41 -0700 Subject: Re: linux-5.7-rc1/tools/testing/selftests/resctrl/cqm_test.c:89:15: error: Buffer is accessed out of bounds To: David Binderman , "fenghua.yu@intel.com" , "shuah@kernel.org" , Linux Kernel Mailing List , "linux-kselftest@vger.kernel.org" , Sai Praneeth Prakhya References: From: Reinette Chatre Message-ID: Date: Mon, 13 Apr 2020 09:30:38 -0700 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org +Sai On 4/13/2020 2:43 AM, David Binderman wrote: > Hello there, > > Source code is > > while (fgets(temp, 1024, fp)) { > > but > > char *token_array[8], temp[512]; > > Use of compiler flag -D_FORTIFY_SOURCE=2 would have found the problem. > For example: > > # include > > extern void g( int); > > void > f( FILE * fp) > { > char buf[ 100]; > > while (fgets( buf, 200, fp) != 0) > { > g( 1); > } > } > > gives > > $ /home/dcb/gcc/results/bin/gcc -c -g -O2 -D_FORTIFY_SOURCE=2 apr13c.cc > In file included from /usr/include/stdio.h:867, > from apr13c.cc:2: > In function ‘char* fgets(char*, int, FILE*)’, > inlined from ‘void f(FILE*)’ at apr13c.cc:11:14: > /usr/include/bits/stdio2.h:263:26: warning: call to ‘__fgets_chk_warn’ declared with attribute warning: fgets called with bigger size than length of destination buffer [-Wattribute-warning] > > I suggest switch on compiler flag -D_FORTIFY_SOURCE=2 in > all development builds. > Thank you very much for catching this David. Sai: could you include this fix in your upcoming series of fixes? Using the pattern of "fgets(buf, sizeof(buf), ...)" instead of hard coding the size should be helpful here. Reinette