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 3E616C7618F for ; Wed, 24 Jul 2019 22:54:26 +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 948BA2190F for ; Wed, 24 Jul 2019 22:54:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 948BA2190F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ACULAB.COM Authentication-Results: mail.kernel.org; spf=none 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 x6OMsDs6026389; Thu, 25 Jul 2019 00:54:13 +0200 (CEST) Received: from systeme.lip6.fr (systeme.lip6.fr [127.0.0.1]) by systeme.lip6.fr (Postfix) with ESMTP id 745D4777C; Thu, 25 Jul 2019 00:54:13 +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 96D1F420D for ; Wed, 24 Jul 2019 12:28:36 +0200 (CEST) Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [146.101.78.151]) by isis.lip6.fr (8.15.2/8.15.2) with ESMTP id x6OASXKG007312 for ; Wed, 24 Jul 2019 12:28:34 +0200 (CEST) Received: from AcuMS.aculab.com (156.67.243.126 [156.67.243.126]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-95-W7Famm5VOkyvDWkWVnd1yQ-1; Wed, 24 Jul 2019 11:28:31 +0100 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b::d117) by AcuMS.aculab.com (fd9f:af1c:a25b::d117) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Wed, 24 Jul 2019 11:28:31 +0100 Received: from AcuMS.Aculab.com ([fe80::43c:695e:880f:8750]) by AcuMS.aculab.com ([fe80::43c:695e:880f:8750%12]) with mapi id 15.00.1347.000; Wed, 24 Jul 2019 11:28:31 +0100 From: David Laight To: "'Joe Perches'" , Julia Lawall Thread-Topic: [Fwd: [PATCH 1/2] string: Add stracpy and stracpy_pad mechanisms] Thread-Index: AQHVQdmROdgsXv6JFEuyvGTo4e2W1qbZkJnA Date: Wed, 24 Jul 2019 10:28:31 +0000 Message-ID: <563222fbfdbb44daa98078db9d404972@AcuMS.aculab.com> References: <7ab8957eaf9b0931a59eff6e2bd8c5169f2f6c41.1563841972.git.joe@perches.com> <66fcdbf607d7d0bea41edb39e5579d63b62b7d84.camel@perches.com> <0f3ba090dfc956f5651e6c7c430abdba94ddcb8b.camel@perches.com> In-Reply-To: Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 X-MC-Unique: W7Famm5VOkyvDWkWVnd1yQ-1 X-Mimecast-Spam-Score: 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]); Thu, 25 Jul 2019 00:54:14 +0200 (CEST) X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.4.3 (isis.lip6.fr [132.227.60.2]); Wed, 24 Jul 2019 12:28:34 +0200 (CEST) X-Scanned-By: MIMEDefang 2.78 on 132.227.60.2 X-Scanned-By: MIMEDefang 2.78 on 132.227.60.2 X-Mailman-Approved-At: Thu, 25 Jul 2019 00:54:12 +0200 Cc: cocci , LKML Subject: Re: [Cocci] [Fwd: [PATCH 1/2] string: Add stracpy and stracpy_pad mechanisms] 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 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. > > > > > > > > julia > > > > > > Nice. Thanks Julia > > > > > > A couple issues: > > > > > > 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); > > > > Sorry, I don't understand the issue here. What specifically should I be > > looking for? > > The return value of strlcpy differs from (strscpy or stracpy). > > strlcpy returns the length of the src string > str[sa]cpy returns the length of the src string if it fits in dest > or -E2BIG if src is truncated by the size of dest > or -E2BIG if dest is 0 length > > 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). OTOH the code almost certainly doesn't expect -E2BIG either so will go wrong in that case as well. The return value from str[as]cpy() is its own set of bugs just waiting to happen. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales) _______________________________________________ Cocci mailing list Cocci@systeme.lip6.fr https://systeme.lip6.fr/mailman/listinfo/cocci