From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-Status: No, score=-5.5 required=3.0 tests=AWL,BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, RCVD_IN_DNSWL_BLOCKED,RCVD_IN_MSPIKE_H4,RCVD_IN_MSPIKE_WL, SPF_HELO_PASS,SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dcvr.yhbt.net (Postfix) with ESMTPS id EDF9A1F4B4 for ; Sat, 2 Jan 2021 03:33:57 +0000 (UTC) Received: from localhost ([::1]:50632 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kvXfw-0008Ca-Nt for normalperson@yhbt.net; Fri, 01 Jan 2021 22:33:56 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:44786) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kvXfu-0008CT-Fw for bug-gnulib@gnu.org; Fri, 01 Jan 2021 22:33:54 -0500 Received: from zimbra.cs.ucla.edu ([131.179.128.68]:38156) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kvXfs-0007aK-CH for bug-gnulib@gnu.org; Fri, 01 Jan 2021 22:33:54 -0500 Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id E7A0816008F; Fri, 1 Jan 2021 19:33:49 -0800 (PST) Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id NwO5u8MXceJi; Fri, 1 Jan 2021 19:33:49 -0800 (PST) Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id 09553160115; Fri, 1 Jan 2021 19:33:49 -0800 (PST) X-Virus-Scanned: amavisd-new at zimbra.cs.ucla.edu Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id Hcl9P-Kr2-p2; Fri, 1 Jan 2021 19:33:48 -0800 (PST) Received: from [192.168.1.9] (cpe-23-243-218-95.socal.res.rr.com [23.243.218.95]) by zimbra.cs.ucla.edu (Postfix) with ESMTPSA id CEF1E160114; Fri, 1 Jan 2021 19:33:48 -0800 (PST) To: Bernhard Voelker References: <2887419.1QkhuepXuh@omega> <1825823.qd5lRurjMP@omega> <1918dba0-3f35-795d-df2c-48e107f725ea@bernhard-voelker.de> From: Paul Eggert Organization: UCLA Computer Science Department Subject: Re: test-getgroups.c:stringop-overflow warning on newer GCC Message-ID: <42ae568f-9f49-bfb3-fbb8-6437fb8c50e1@cs.ucla.edu> Date: Fri, 1 Jan 2021 19:33:48 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.5.0 MIME-Version: 1.0 In-Reply-To: <1918dba0-3f35-795d-df2c-48e107f725ea@bernhard-voelker.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=131.179.128.68; envelope-from=eggert@cs.ucla.edu; helo=zimbra.cs.ucla.edu X-Spam_score_int: -68 X-Spam_score: -6.9 X-Spam_bar: ------ X-Spam_report: (-6.9 / 5.0 requ) BAYES_00=-1.9, NICE_REPLY_A=-2.749, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: bug-gnulib@gnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Gnulib discussion list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Bruno Haible , bug-gnulib@gnu.org Errors-To: bug-gnulib-bounces+normalperson=yhbt.net@gnu.org Sender: "bug-gnulib" On 1/1/21 6:30 PM, Bernhard Voelker wrote: > As I see the same on Fedora, the issue seems to be upstream, doesn't it= ? I see the problem on Fedora 33 as well. It doesn't appear to be a GCC=20 bug. unistd.h's declaration expands to this: extern int getgroups (int __size, __gid_t __list[]) __attribute__=20 ((__nothrow__, __leaf__)) __attribute__ ((__access__ (__write_only__, 2,=20 1))); and the "__write_only__, 2, 1" means that getgroup's 1st argument=20 specifies the number of items in the 2nd-argument array, which means if=20 the 1st argument is -1 the call is invalid. This checking is enabled by=20 -Wstringop-overflow=3D2 which is the GCC default in 10.2.1. I am using gcc (GCC) 10.2.1 20201125 (Red Hat 10.2.1-9).