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=-8.2 required=3.0 tests=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 A775AC433DF for ; Wed, 17 Jun 2020 20:28:01 +0000 (UTC) Received: from isis.lip6.fr (isis.lip6.fr [132.227.60.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 17926214DB for ; Wed, 17 Jun 2020 20:28:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 17926214DB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=inria.fr Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=cocci-bounces@systeme.lip6.fr Received: from systeme.lip6.fr (systeme.lip6.fr [132.227.104.7]) by isis.lip6.fr (8.15.2/8.15.2) with ESMTP id 05HKRn12007098; Wed, 17 Jun 2020 22:27:49 +0200 (CEST) Received: from systeme.lip6.fr (systeme.lip6.fr [127.0.0.1]) by systeme.lip6.fr (Postfix) with ESMTP id E92CB7577; Wed, 17 Jun 2020 22:27:48 +0200 (CEST) Received: from isis.lip6.fr (isis.lip6.fr [132.227.60.2]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by systeme.lip6.fr (Postfix) with ESMTPS id A76AA3D0F for ; Wed, 17 Jun 2020 22:27:47 +0200 (CEST) Received: from mail2-relais-roc.national.inria.fr (mail2-relais-roc.national.inria.fr [192.134.164.83]) by isis.lip6.fr (8.15.2/8.15.2) with ESMTPS id 05HKRhnM010890 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Wed, 17 Jun 2020 22:27:43 +0200 (CEST) X-IronPort-AV: E=Sophos;i="5.73,523,1583190000"; d="scan'208";a="455254845" Received: from abo-173-121-68.mrs.modulonet.fr (HELO hadrien) ([85.68.121.173]) by mail2-relais-roc.national.inria.fr with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 17 Jun 2020 22:27:43 +0200 Date: Wed, 17 Jun 2020 22:27:43 +0200 (CEST) From: Julia Lawall X-X-Sender: jll@hadrien To: Denis Efremov In-Reply-To: <20200615130242.11825-1-efremov@linux.com> Message-ID: References: <20200615130242.11825-1-efremov@linux.com> User-Agent: Alpine 2.22 (DEB 394 2020-01-19) MIME-Version: 1.0 X-Greylist: Sender IP whitelisted, Sender e-mail whitelisted, not delayed by milter-greylist-4.4.3 (isis.lip6.fr [132.227.60.2]); Wed, 17 Jun 2020 22:27:49 +0200 (CEST) X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.4.3 (isis.lip6.fr [132.227.60.2]); Wed, 17 Jun 2020 22:27:43 +0200 (CEST) X-Scanned-By: MIMEDefang 2.78 on 132.227.60.2 X-Scanned-By: MIMEDefang 2.78 on 132.227.60.2 Cc: linux-kernel@vger.kernel.org, cocci@systeme.lip6.fr Subject: Re: [Cocci] [PATCH] coccinelle: api: add device_attr_show script X-BeenThere: cocci@systeme.lip6.fr X-Mailman-Version: 2.1.13 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: cocci-bounces@systeme.lip6.fr Errors-To: cocci-bounces@systeme.lip6.fr On Mon, 15 Jun 2020, Denis Efremov wrote: > According to the documentation[1] show() methods of device attributes > should return the number of bytes printed into the buffer. This is > the return value of scnprintf(). show() must not use snprintf() > when formatting the value to be returned to user space. snprintf() > returns the length the resulting string would be, assuming it all > fit into the destination array[2]. scnprintf() return the length of > the string actually created in buf. If one can guarantee that an > overflow will never happen sprintf() can be used otherwise scnprintf(). The semantic patch looks fine. Do you have any accepted patches from this? julia > > [1] Documentation/filesystems/sysfs.txt > [2] "snprintf() confusion" https://lwn.net/Articles/69419/ > > Signed-off-by: Denis Efremov > --- > scripts/coccinelle/api/device_attr_show.cocci | 55 +++++++++++++++++++ > 1 file changed, 55 insertions(+) > create mode 100644 scripts/coccinelle/api/device_attr_show.cocci > > diff --git a/scripts/coccinelle/api/device_attr_show.cocci b/scripts/coccinelle/api/device_attr_show.cocci > new file mode 100644 > index 000000000000..d8ec4bb8ac41 > --- /dev/null > +++ b/scripts/coccinelle/api/device_attr_show.cocci > @@ -0,0 +1,55 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/// > +/// From Documentation/filesystems/sysfs.txt: > +/// show() must not use snprintf() when formatting the value to be > +/// returned to user space. If you can guarantee that an overflow > +/// will never happen you can use sprintf() otherwise you must use > +/// scnprintf(). > +/// > +// Confidence: High > +// Copyright: (C) 2020 Denis Efremov ISPRAS > +// Options: --no-includes --include-headers > +// > + > +virtual report > +virtual org > +virtual context > +virtual patch > + > +@r depends on !patch@ > +identifier show, dev, attr, buf; > +position p; > +@@ > + > +ssize_t show(struct device *dev, struct device_attribute *attr, char *buf) > +{ > + <... > +* return snprintf@p(...); > + ...> > +} > + > +@rp depends on patch@ > +identifier show, dev, attr, buf; > +@@ > + > +ssize_t show(struct device *dev, struct device_attribute *attr, char *buf) > +{ > + <... > + return > +- snprintf > ++ scnprintf > + (...); > + ...> > +} > + > +@script: python depends on report@ > +p << r.p; > +@@ > + > +coccilib.report.print_report(p[0], "WARNING: use scnprintf or sprintf") > + > +@script: python depends on org@ > +p << r.p; > +@@ > + > +coccilib.org.print_todo(p[0], "WARNING: use scnprintf or sprintf") > -- > 2.26.2 > > _______________________________________________ > Cocci mailing list > Cocci@systeme.lip6.fr > https://systeme.lip6.fr/mailman/listinfo/cocci > _______________________________________________ Cocci mailing list Cocci@systeme.lip6.fr https://systeme.lip6.fr/mailman/listinfo/cocci