From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by sourceware.org (Postfix) with ESMTP id 07F913857813 for ; Mon, 26 Oct 2020 15:42:02 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 07F913857813 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-345-G-vIIPRnN2Stht8fnCh-6A-1; Mon, 26 Oct 2020 11:41:58 -0400 X-MC-Unique: G-vIIPRnN2Stht8fnCh-6A-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E682D1087D62; Mon, 26 Oct 2020 15:41:57 +0000 (UTC) Received: from oldenburg2.str.redhat.com (ovpn-114-87.ams2.redhat.com [10.36.114.87]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3E6CB5C1BB; Mon, 26 Oct 2020 15:41:57 +0000 (UTC) From: Florian Weimer To: Martin Sebor via Libc-alpha Subject: Re: [PATCH] more out of bounds checking improvements References: <176ba75f-4299-073f-8319-66dbf9fe3f42@gmail.com> Date: Mon, 26 Oct 2020 16:41:55 +0100 In-Reply-To: <176ba75f-4299-073f-8319-66dbf9fe3f42@gmail.com> (Martin Sebor via Libc-alpha's message of "Mon, 26 Oct 2020 09:01:24 -0600") Message-ID: <87mu09ata4.fsf@oldenburg2.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-6.3 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H4, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 26 Oct 2020 15:42:03 -0000 * Martin Sebor via Libc-alpha: > Besides attribute access, the change adds attribute nonnull to > the readv and writev functions in misc/sys/uio.h. The functions > don't necessarily access the array elements when their count is > zero but neither POSIX nor the Linux manual document this so it > seems appropriate to warn. This change is questionable because it breaks interoperability with abstract data types such as std::vector, where the base pointer can be null when the array is empty. The kernel does not return EFAULT in this case, as expected. I think we need a special case for this. Thanks, Florian -- Red Hat GmbH, https://de.redhat.com/ , Registered seat: Grasbrunn, Commercial register: Amtsgericht Muenchen, HRB 153243, Managing Directors: Charles Cachera, Brian Klemm, Laurie Krebs, Michael O'Neill