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 0D2C5C7618B for ; Wed, 24 Jul 2019 11:45:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D6C2422387 for ; Wed, 24 Jul 2019 11:45:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727733AbfGXLp1 (ORCPT ); Wed, 24 Jul 2019 07:45:27 -0400 Received: from mail2-relais-roc.national.inria.fr ([192.134.164.83]:39712 "EHLO mail2-relais-roc.national.inria.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727128AbfGXLp1 (ORCPT ); Wed, 24 Jul 2019 07:45:27 -0400 X-IronPort-AV: E=Sophos;i="5.64,302,1559512800"; d="scan'208";a="393144701" Received: from c-73-22-29-55.hsd1.il.comcast.net (HELO hadrien) ([73.22.29.55]) by mail2-relais-roc.national.inria.fr with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 24 Jul 2019 13:45:24 +0200 Date: Wed, 24 Jul 2019 06:45:23 -0500 (CDT) From: Julia Lawall X-X-Sender: jll@hadrien To: Joe Perches cc: David Laight , cocci , LKML Subject: Re: [Fwd: [PATCH 1/2] string: Add stracpy and stracpy_pad mechanisms] In-Reply-To: Message-ID: References: <7ab8957eaf9b0931a59eff6e2bd8c5169f2f6c41.1563841972.git.joe@perches.com> <66fcdbf607d7d0bea41edb39e5579d63b62b7d84.camel@perches.com> <0f3ba090dfc956f5651e6c7c430abdba94ddcb8b.camel@perches.com> <563222fbfdbb44daa98078db9d404972@AcuMS.aculab.com> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 24 Jul 2019, Joe Perches wrote: > 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 OK, it's easy to check for in any case. Thanks. julia