From patchwork Wed Mar 10 00:02:54 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 396511 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=-17.0 required=3.0 tests=BAYES_00, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT 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 C6CE4C433E0 for ; Wed, 10 Mar 2021 00:03:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9B0F064FB5 for ; Wed, 10 Mar 2021 00:03:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232130AbhCJADV convert rfc822-to-8bit (ORCPT ); Tue, 9 Mar 2021 19:03:21 -0500 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:51822 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S231216AbhCJADB (ORCPT ); Tue, 9 Mar 2021 19:03:01 -0500 Received: from pps.filterd (m0089730.ppops.net [127.0.0.1]) by m0089730.ppops.net (8.16.0.43/8.16.0.43) with SMTP id 129Ntuij019001 for ; Tue, 9 Mar 2021 16:03:01 -0800 Received: from maileast.thefacebook.com ([163.114.130.16]) by m0089730.ppops.net with ESMTP id 376be72w88-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Tue, 09 Mar 2021 16:03:01 -0800 Received: from intmgw001.38.frc1.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:82::d) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Tue, 9 Mar 2021 16:02:59 -0800 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id 43F012ED1C63; Tue, 9 Mar 2021 16:02:56 -0800 (PST) From: Andrii Nakryiko To: , , , CC: , Subject: [PATCH bpf-next 1/2] libbpf: add explicit padding to bpf_xdp_set_link_opts Date: Tue, 9 Mar 2021 16:02:54 -0800 Message-ID: <20210310000254.4140487-1-andrii@kernel.org> X-Mailer: git-send-email 2.24.1 MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.369, 18.0.761 definitions=2021-03-09_20:2021-03-09,2021-03-09 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 mlxscore=0 mlxlogscore=563 phishscore=0 priorityscore=1501 lowpriorityscore=0 malwarescore=0 impostorscore=0 bulkscore=0 adultscore=0 clxscore=1015 spamscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2103090118 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Adding such anonymous padding fixes the issue with uninitialized portions of bpf_xdp_set_link_opts when using LIBBPF_DECLARE_OPTS macro with inline field initialization: DECLARE_LIBBPF_OPTS(bpf_xdp_set_link_opts, opts, .old_fd = -1); When such code is compiled in debug mode, compiler is generating code that leaves padding bytes uninitialized, which triggers error inside libbpf APIs that do strict zero initialization checks for OPTS structs. Adding anonymous padding field fixes the issue. Fixes: bd5ca3ef93cd ("libbpf: Add function to set link XDP fd while specifying old program") Signed-off-by: Andrii Nakryiko --- tools/lib/bpf/libbpf.h | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index 3c35eb401931..3d690d4e785c 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -507,6 +507,7 @@ struct xdp_link_info { struct bpf_xdp_set_link_opts { size_t sz; int old_fd; + size_t :0; }; #define bpf_xdp_set_link_opts__last_field old_fd