From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS3215 2.6.0.0/16 X-Spam-Status: No, score=-4.2 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI,SPF_HELO_PASS,SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from sourceware.org (server2.sourceware.org [IPv6:2620:52:3:1:0:246e:9693:128c]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by dcvr.yhbt.net (Postfix) with ESMTPS id 6136E1F601 for ; Sun, 4 Dec 2022 18:46:43 +0000 (UTC) Authentication-Results: dcvr.yhbt.net; dkim=pass (1024-bit key; secure) header.d=sourceware.org header.i=@sourceware.org header.b="omsCVc1e"; dkim-atps=neutral Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id A6A6238432E2 for ; Sun, 4 Dec 2022 18:46:40 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org A6A6238432E2 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1670179600; bh=AJ7oTYHd5ufy9+RVLzStIB7J+lZbdGWnAr+U38sTOTE=; h=To:Cc:Subject:References:Date:In-Reply-To:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From:Reply-To:From; b=omsCVc1eMezPqeg4ZIVghhUTG2w+CbRyltCstKg+YTWL1IKH2Dk3VRAwQbsjfHSc5 AT/hyECNuOREZgzJ0/S3XK+fvZHr267eMbEGl312HgVzNoCqg8uOACFn53BVbJ6J+/ 7vaME5ycE68tjcIUaAYD3vfRpHn/dkbHeifItq2I= Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id 08DAB38432F6 for ; Sun, 4 Dec 2022 18:46:22 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 08DAB38432F6 Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-498-aumXrjAvOkOgk3DYvcEDug-1; Sun, 04 Dec 2022 13:46:20 -0500 X-MC-Unique: aumXrjAvOkOgk3DYvcEDug-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 0D68985A588; Sun, 4 Dec 2022 18:46:20 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.2.16.33]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2E1FCC15BB2; Sun, 4 Dec 2022 18:46:18 +0000 (UTC) To: Alejandro Colomar via Libc-alpha Cc: Xi Ruoyao , Andreas Schwab , Alejandro Colomar Subject: Re: bind(2): Missing [[gnu::nonnull]] References: <8292ef824696e0fbac4f4ed036aad43c0458b8a2.camel@xry111.site> <87wn78cnpe.fsf@igel.home> <4e085ada-10eb-9de9-7681-1c96ec74da30@gmail.com> Date: Sun, 04 Dec 2022 19:46:15 +0100 In-Reply-To: <4e085ada-10eb-9de9-7681-1c96ec74da30@gmail.com> (Alejandro Colomar via Libc-alpha's message of "Sun, 4 Dec 2022 12:14:56 +0100") Message-ID: <87y1rnf1mw.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.8 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain 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: , From: Florian Weimer via Libc-alpha Reply-To: Florian Weimer Errors-To: libc-alpha-bounces+e=80x24.org@sourceware.org Sender: "Libc-alpha" * Alejandro Colomar via Libc-alpha: > Hi Xi, > > On 12/4/22 06:59, Xi Ruoyao wrote: >> On Sat, 2022-12-03 at 20:05 +0100, Andreas Schwab wrote: >>>> Currently the man page says: >>>> >>>> EFAULT: addr points outside the user's accessible address space. >>>> >>>> And bind(2) indeed sets errno to EFAULT and return -1 when NULL is >>>> passed as addr. >>> >>> You can never depend on EFAULT for invalid addresses. >> Hmm, is this documented somewhere? > > I don't know, but let me have an educated guess: > > Holding a pointer to invalid memory is Undefined Behavior by the > standard, except if that pointer is NULL, or is still indeterminate > because the pointer has not yet been initialized with a valid address. > Using an uninitialized pointer is UB as using any uninitialized > variable. Using a NULL pointer is only okay for comparisons, or as a > sentinel value, but never for accessing memory. So chances are high > that the program will already have invoked UB at the time bind(2) is > called with an invalid address. Currently, Linux does not report for vDSO-accelerated system calls, but generates SIGSEGV. We received bug reports when we added vDSO support for time/gettimeofday/clock_gettime because some tests were relying on the EFAULT behavior. Thanks, Florian