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=-3.8 required=3.0 tests=BAYES_00, 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 27870C48BDF for ; Fri, 18 Jun 2021 08:42:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0DA826120D for ; Fri, 18 Jun 2021 08:42:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233875AbhFRIob convert rfc822-to-8bit (ORCPT ); Fri, 18 Jun 2021 04:44:31 -0400 Received: from eu-smtp-delivery-151.mimecast.com ([207.82.80.151]:36420 "EHLO eu-smtp-delivery-151.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233775AbhFRIoa (ORCPT ); Fri, 18 Jun 2021 04:44:30 -0400 Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mtapsc-8-S_lREQziMlqph1PADEonZw-1; Fri, 18 Jun 2021 09:42:17 +0100 X-MC-Unique: S_lREQziMlqph1PADEonZw-1 Received: from AcuMS.Aculab.com (10.202.163.4) by AcuMS.aculab.com (10.202.163.4) with Microsoft SMTP Server (TLS) id 15.0.1497.18; Fri, 18 Jun 2021 09:42:16 +0100 Received: from AcuMS.Aculab.com ([fe80::994c:f5c2:35d6:9b65]) by AcuMS.aculab.com ([fe80::994c:f5c2:35d6:9b65%12]) with mapi id 15.00.1497.018; Fri, 18 Jun 2021 09:42:16 +0100 From: David Laight To: 'Kees Cook' , "netdev@vger.kernel.org" CC: Johannes Berg , "David S. Miller" , Jakub Kicinski , "linux-kernel@vger.kernel.org" , "linux-wireless@vger.kernel.org" , "linux-hardening@vger.kernel.org" Subject: RE: [PATCH] mac80211: Recast pointer for trailing memcpy() Thread-Topic: [PATCH] mac80211: Recast pointer for trailing memcpy() Thread-Index: AQHXYzENJy6TjXiKVkqMQny50fQUFqsZdDaA Date: Fri, 18 Jun 2021 08:42:16 +0000 Message-ID: <1bd7df33fd484d1da656238f792bd6f7@AcuMS.aculab.com> References: <20210617042709.2170111-1-keescook@chromium.org> In-Reply-To: <20210617042709.2170111-1-keescook@chromium.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: linux-wireless@vger.kernel.org From: Kees Cook > Sent: 17 June 2021 05:27 > > In preparation for FORTIFY_SOURCE performing compile-time and run-time > field bounds checking for memcpy(), memmove(), and memset(), avoid > intentionally writing across neighboring array fields. > > Give memcpy() a specific source pointer type so it can correctly > calculate the bounds of the copy. Doesn't the necessity of this sort of patch just sidestep the run-time checking and really indicate that it is just a complete waste of cpu resources? I bet code changes to avoid/fix the reported errors will introduce more bugs than the test itself will really find. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)