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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 D8664C5519F for ; Mon, 30 Nov 2020 09:20:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8CFB020809 for ; Mon, 30 Nov 2020 09:20:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727102AbgK3JUj convert rfc822-to-8bit (ORCPT ); Mon, 30 Nov 2020 04:20:39 -0500 Received: from eu-smtp-delivery-151.mimecast.com ([207.82.80.151]:26708 "EHLO eu-smtp-delivery-151.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726498AbgK3JUj (ORCPT ); Mon, 30 Nov 2020 04:20:39 -0500 Received: from AcuMS.aculab.com (156.67.243.126 [156.67.243.126]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-144-Q0MlZ52vP8mTVg-vKwyGSQ-1; Mon, 30 Nov 2020 09:19:00 +0000 X-MC-Unique: Q0MlZ52vP8mTVg-vKwyGSQ-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) by AcuMS.aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Mon, 30 Nov 2020 09:18:59 +0000 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; Mon, 30 Nov 2020 09:18:59 +0000 From: David Laight To: 'Stephen Hemminger' , "netdev@vger.kernel.org" Subject: RE: [PATCH 4/5] misc: fix compiler warning in ifstat and nstat Thread-Topic: [PATCH 4/5] misc: fix compiler warning in ifstat and nstat Thread-Index: AQHWxq89V9V+Fa2vMUOjPZD4kiCxKKngZaNw Date: Mon, 30 Nov 2020 09:18:59 +0000 Message-ID: References: <20201130002135.6537-1-stephen@networkplumber.org> <20201130002135.6537-5-stephen@networkplumber.org> In-Reply-To: <20201130002135.6537-5-stephen@networkplumber.org> Accept-Language: en-GB, 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 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=C51A453 smtp.mailfrom=david.laight@aculab.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Stephen Hemminger > Sent: 30 November 2020 00:22 > > The code here was doing strncpy() in a way that causes gcc 10 > warning about possible string overflow. Just use strlcpy() which > will null terminate and bound the string as expected. > > This has existed since start of git era so no Fixes tag. > > Signed-off-by: Stephen Hemminger > --- > misc/ifstat.c | 2 +- > misc/nstat.c | 3 +-- > 2 files changed, 2 insertions(+), 3 deletions(-) > > diff --git a/misc/ifstat.c b/misc/ifstat.c > index c05183d79a13..d4a33429dc50 100644 > --- a/misc/ifstat.c > +++ b/misc/ifstat.c > @@ -251,7 +251,7 @@ static void load_raw_table(FILE *fp) > buf[strlen(buf)-1] = 0; > if (info_source[0] && strcmp(info_source, buf+1)) > source_mismatch = 1; > - strncpy(info_source, buf+1, sizeof(info_source)-1); > + strlcpy(info_source, buf+1, sizeof(info_source)); > continue; ISTM that once it has done a strlen() it ought to use the length for the later copy. I don't seem to have the source file (I'm guessing it isn't in the normal repo), but is that initial strlen() guaranteed not to return zero? David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)