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=-11.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 3D438C433E0 for ; Fri, 17 Jul 2020 10:21:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1D1B22070E for ; Fri, 17 Jul 2020 10:21:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726013AbgGQKVB (ORCPT ); Fri, 17 Jul 2020 06:21:01 -0400 Received: from correo.us.es ([193.147.175.20]:52758 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725864AbgGQKVB (ORCPT ); Fri, 17 Jul 2020 06:21:01 -0400 Received: from antivirus1-rhel7.int (unknown [192.168.2.11]) by mail.us.es (Postfix) with ESMTP id 127DDE2C52 for ; Fri, 17 Jul 2020 12:21:00 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 01C28DA78B for ; Fri, 17 Jul 2020 12:21:00 +0200 (CEST) Received: by antivirus1-rhel7.int (Postfix, from userid 99) id EB58DDA73D; Fri, 17 Jul 2020 12:20:59 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 470C1DA78B; Fri, 17 Jul 2020 12:20:57 +0200 (CEST) Received: from 192.168.1.97 (192.168.1.97) by antivirus1-rhel7.int (F-Secure/fsigk_smtp/550/antivirus1-rhel7.int); Fri, 17 Jul 2020 12:20:57 +0200 (CEST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/antivirus1-rhel7.int) Received: from us.es (unknown [90.77.255.23]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: 1984lsi) by entrada.int (Postfix) with ESMTPSA id 2284B42EF4E1; Fri, 17 Jul 2020 12:20:57 +0200 (CEST) Date: Fri, 17 Jul 2020 12:20:56 +0200 X-SMTPAUTHUS: auth mail.us.es From: Pablo Neira Ayuso To: Phil Sutter , netfilter-devel@vger.kernel.org Subject: Re: [nf-next PATCH] netfilter: include: uapi: Use C99 flexible array member Message-ID: <20200717102056.GA18560@salvia> References: <20200713111552.25399-1-phil@nwl.cc> <20200715181433.GA17636@salvia> <20200717100648.GE23632@orbyte.nwl.cc> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200717100648.GE23632@orbyte.nwl.cc> User-Agent: Mutt/1.10.1 (2018-07-13) X-Virus-Scanned: ClamAV using ClamSMTP Sender: netfilter-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org On Fri, Jul 17, 2020 at 12:06:48PM +0200, Phil Sutter wrote: > Hi Pablo, > > On Wed, Jul 15, 2020 at 08:14:33PM +0200, Pablo Neira Ayuso wrote: > > On Mon, Jul 13, 2020 at 01:15:52PM +0200, Phil Sutter wrote: > > [...] > > > Avoid this warning by declaring 'entries' as an ISO C99 flexible array > > > member. This makes gcc aware of the intended use and enables sanity > > > checking as described in: > > > https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html > > > > > > Signed-off-by: Phil Sutter > > > --- > > > include/uapi/linux/netfilter_ipv4/ip_tables.h | 2 +- > > > include/uapi/linux/netfilter_ipv6/ip6_tables.h | 2 +- > > > 2 files changed, 2 insertions(+), 2 deletions(-) > > > > > > diff --git a/include/uapi/linux/netfilter_ipv4/ip_tables.h b/include/uapi/linux/netfilter_ipv4/ip_tables.h > > > index 50c7fee625ae9..1a298cc7a29c1 100644 > > > --- a/include/uapi/linux/netfilter_ipv4/ip_tables.h > > > +++ b/include/uapi/linux/netfilter_ipv4/ip_tables.h > > > @@ -203,7 +203,7 @@ struct ipt_replace { > > > struct xt_counters __user *counters; > > > > > > /* The entries (hang off end: not really an array). */ > > > - struct ipt_entry entries[0]; > > > + struct ipt_entry entries[]; > > > > arpt_replace uses this idiom too. > > Oh, indeed. I focussed on those cases gcc complained about when > compiling iptables. Grepping for '\[0\]' in all of > include/uapi/linux/netfilter* reveals a few more cases. Do you think > it's worth "fixing" those as well? It seems this patch was missing a few spots, right? commit 6daf14140129d30207ed6a0a69851fa6a3636bda Author: Gustavo A. R. Silva Date: Thu Feb 20 07:59:14 2020 -0600 netfilter: Replace zero-length array with flexible-array member Probably Cc: Gustavo to confirm this.