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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 17920C7618B for ; Wed, 24 Jul 2019 10:43:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E291C229ED for ; Wed, 24 Jul 2019 10:43:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726828AbfGXKn0 (ORCPT ); Wed, 24 Jul 2019 06:43:26 -0400 Received: from smtprelay0152.hostedemail.com ([216.40.44.152]:54892 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726070AbfGXKn0 (ORCPT ); Wed, 24 Jul 2019 06:43:26 -0400 Received: from filter.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay04.hostedemail.com (Postfix) with ESMTP id 423DB180A68A2; Wed, 24 Jul 2019 10:43:25 +0000 (UTC) X-Session-Marker: 6A6F6540706572636865732E636F6D X-HE-Tag: lip98_a3a5877a904 X-Filterd-Recvd-Size: 3083 Received: from XPS-9350 (cpe-23-242-196-136.socal.res.rr.com [23.242.196.136]) (Authenticated sender: joe@perches.com) by omf20.hostedemail.com (Postfix) with ESMTPA; Wed, 24 Jul 2019 10:43:24 +0000 (UTC) Message-ID: Subject: Re: [Fwd: [PATCH 1/2] string: Add stracpy and stracpy_pad mechanisms] From: Joe Perches To: David Laight , Julia Lawall Cc: cocci , LKML Date: Wed, 24 Jul 2019 03:43:22 -0700 In-Reply-To: <563222fbfdbb44daa98078db9d404972@AcuMS.aculab.com> References: <7ab8957eaf9b0931a59eff6e2bd8c5169f2f6c41.1563841972.git.joe@perches.com> <66fcdbf607d7d0bea41edb39e5579d63b62b7d84.camel@perches.com> <0f3ba090dfc956f5651e6c7c430abdba94ddcb8b.camel@perches.com> <563222fbfdbb44daa98078db9d404972@AcuMS.aculab.com> Content-Type: text/plain; charset="ISO-8859-1" User-Agent: Evolution 3.30.5-0ubuntu0.18.10.1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2019-07-24 at 10:28 +0000, David Laight wrote: > From: Joe Perches > > Sent: 24 July 2019 05:38 > > On Tue, 2019-07-23 at 23:27 -0500, Julia Lawall wrote: > > > On Tue, 23 Jul 2019, Joe Perches wrote: > > > > On Tue, 2019-07-23 at 22:54 -0500, Julia Lawall wrote: > > > > > A seantic patch and the resulting output for the case where the third > > > > > arugument is a constant is attached. Likewise the resulting output on a > > > > > recent linux-next. [] > > > > There is a problem with conversions with assignments > > > > of strlcpy() so ideally the cocci script should make sure > > > > any return value was not used before conversion. > > > > > > > > This is not a provably good conversion: > > > > > > > > drivers/s390/char/sclp_ftp.c > > > > @@ -114,8 +114,7 @@ static int sclp_ftp_et7(const struct hmc > > > > sccb->evbuf.mdd.ftp.length = ftp->len; > > > > sccb->evbuf.mdd.ftp.bufaddr = virt_to_phys(ftp->buf); > > > > > > > > - len = strlcpy(sccb->evbuf.mdd.ftp.fident, ftp->fname, > > > > - HMCDRV_FTP_FIDENT_MAX); > > > > + len = stracpy(sccb->evbuf.mdd.ftp.fident, ftp->fname); [] > > Any use of the strlcpy return value should not be converted > > because the logic after an assignment or use of the return value > > can not be assured to have the same behavior. > > Most of the code probably expects the length to be that copied > (so is broken if the string is truncated). Fortunately there are relatively few uses of the return value of strlcpy so it's not a large problem set. Slightly unrepresentative counts: $ git grep -P "^\s+strlcpy\b" | wc -l 1681 $ git grep -P "=\s*strlcpy\b" | wc -l 28