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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 778A3C4360C for ; Sun, 13 Oct 2019 10:17:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5A97F20679 for ; Sun, 13 Oct 2019 10:17:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728816AbfJMKRx (ORCPT ); Sun, 13 Oct 2019 06:17:53 -0400 Received: from relay2-d.mail.gandi.net ([217.70.183.194]:50343 "EHLO relay2-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728528AbfJMKRx (ORCPT ); Sun, 13 Oct 2019 06:17:53 -0400 X-Originating-IP: 90.177.210.238 Received: from [192.168.1.110] (238.210.broadband10.iol.cz [90.177.210.238]) (Authenticated sender: i.maximets@ovn.org) by relay2-d.mail.gandi.net (Postfix) with ESMTPSA id 9ADA440004; Sun, 13 Oct 2019 10:17:48 +0000 (UTC) Subject: Re: [PATCH bpf v2] libbpf: fix passing uninitialized bytes to setsockopt To: Alexei Starovoitov , Ilya Maximets Cc: "netdev@vger.kernel.org" , "bpf@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Alexei Starovoitov , Daniel Borkmann , "David S . Miller" , Jonathan Lemon , Andrii Nakryiko References: <5da24d48.1c69fb81.a3069.c817SMTPIN_ADDED_BROKEN@mx.google.com> <20191012232437.2xpi5mmmv7mxz3yy@ast-mbp.dhcp.thefacebook.com> From: Ilya Maximets Message-ID: Date: Sun, 13 Oct 2019 12:17:47 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20191012232437.2xpi5mmmv7mxz3yy@ast-mbp.dhcp.thefacebook.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 13.10.2019 1:24, Alexei Starovoitov wrote: > On Wed, Oct 09, 2019 at 06:49:29PM +0200, Ilya Maximets wrote: >> 'struct xdp_umem_reg' has 4 bytes of padding at the end that makes >> valgrind complain about passing uninitialized stack memory to the >> syscall: >> >> Syscall param socketcall.setsockopt() points to uninitialised byte(s) >> at 0x4E7AB7E: setsockopt (in /usr/lib64/libc-2.29.so) >> by 0x4BDE035: xsk_umem__create@@LIBBPF_0.0.4 (xsk.c:172) >> Uninitialised value was created by a stack allocation >> at 0x4BDDEBA: xsk_umem__create@@LIBBPF_0.0.4 (xsk.c:140) >> >> Padding bytes appeared after introducing of a new 'flags' field. >> memset() is required to clear them. >> >> Fixes: 10d30e301732 ("libbpf: add flags to umem config") >> Signed-off-by: Ilya Maximets >> --- >> >> Version 2: >> * Struct initializer replaced with explicit memset(). [Andrii] >> >> tools/lib/bpf/xsk.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c >> index a902838f9fcc..9d5348086203 100644 >> --- a/tools/lib/bpf/xsk.c >> +++ b/tools/lib/bpf/xsk.c >> @@ -163,6 +163,7 @@ int xsk_umem__create_v0_0_4(struct xsk_umem **umem_ptr, void *umem_area, >> umem->umem_area = umem_area; >> xsk_set_umem_config(&umem->config, usr_config); >> >> + memset(&mr, 0, sizeof(mr)); >> mr.addr = (uintptr_t)umem_area; >> mr.len = size; >> mr.chunk_size = umem->config.frame_size; > > This was already applied. Why did you resend? > Sorry, it wasn't me. Looking at the mail delivery chain: Received: from listssympa-test.colorado.edu (listssympa-test.colorado.edu [128.138.129.156]) by spool.mail.gandi.net (Postfix) with ESMTPS id 66E2F780445 for ; Sun, 13 Oct 2019 04:52:14 +0000 (UTC) Received: from listssympa-test.colorado.edu (localhost [127.0.0.1]) by listssympa-test.colorado.edu (8.15.2/8.15.2/MJC-8.0/sympa) with ESMTPS id x9D4pvsL015926 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Sat, 12 Oct 2019 22:51:57 -0600 Received: (from root@localhost) by listssympa-test.colorado.edu (8.15.2/8.15.2/MJC-8.0/submit) id x9D4pujl015885; Sat, 12 Oct 2019 22:51:56 -0600 Received: from DM5PR03MB3273.namprd03.prod.outlook.com (2603:10b6:a03:54::17) by BYAPR03MB4376.namprd03.prod.outlook.com with HTTPS via BYAPR02CA0040.NAMPRD02.PROD.OUTLOOK.COM; Wed, 9 Oct 2019 22:04:15 +0000 Received: from BN6PR03CA0057.namprd03.prod.outlook.com (2603:10b6:404:4c::19) by DM5PR03MB3273.namprd03.prod.outlook.com (2603:10b6:4:42::32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2347.16; Wed, 9 Oct 2019 17:44:13 +0000 There is some strange server listssympa-test.colorado.edu. Looks like someone in colorado.edu is testing stuff on production server. The simplified delivery chain looks like this: Me -> relay6-d.mail.gandi.net -> vger.kernel.org -> mx.colorado.edu -> mail.protection.outlook.com -> namprd03.prod.outlook.com -> listssympa-test.colorado.edu -> spool.mail.gandi.net -> Me again! Best regards, Ilya Maximets.