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=-9.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 F15F2C7618F for ; Wed, 24 Jul 2019 21:48:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C930F21850 for ; Wed, 24 Jul 2019 21:48:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="eLFTHQoV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726997AbfGXVsh (ORCPT ); Wed, 24 Jul 2019 17:48:37 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:64132 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726870AbfGXVsg (ORCPT ); Wed, 24 Jul 2019 17:48:36 -0400 Received: from pps.filterd (m0109334.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x6OLmGsI024535 for ; Wed, 24 Jul 2019 14:48:35 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : mime-version : content-type; s=facebook; bh=vIYOJ8GFUHIG0Z6RRTPyodtUTdV1z6zUK00ElCW6/EE=; b=eLFTHQoVgkta5/hakWnl739UtWnjnqnOH8Bo6CAFbdYW/ULG1wCM61IDp70bMh6Lds3i MPLPiNJNf0MIWQxvIhtgPW53YINznUfAVbRIdK1I4jr5JegKltvPpuYRa8gbOX5+zSg4 gK5IrcT/b7wb6hAd5/AHVgVug3mblS745Q8= Received: from mail.thefacebook.com (mailout.thefacebook.com [199.201.64.23]) by mx0a-00082601.pphosted.com with ESMTP id 2txs429seu-4 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT) for ; Wed, 24 Jul 2019 14:48:35 -0700 Received: from mx-out.facebook.com (2620:10d:c081:10::13) by mail.thefacebook.com (2620:10d:c081:35::130) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA) id 15.1.1713.5; Wed, 24 Jul 2019 14:48:33 -0700 Received: by dev101.prn2.facebook.com (Postfix, from userid 137359) id C8F228615C6; Wed, 24 Jul 2019 14:48:32 -0700 (PDT) Smtp-Origin-Hostprefix: dev From: Andrii Nakryiko Smtp-Origin-Hostname: dev101.prn2.facebook.com To: , , , CC: , , Andrii Nakryiko , Magnus Karlsson Smtp-Origin-Cluster: prn2c23 Subject: [PATCH v2 bpf] libbpf: silence GCC8 warning about string truncation Date: Wed, 24 Jul 2019 14:47:53 -0700 Message-ID: <20190724214753.1816451-1-andriin@fb.com> X-Mailer: git-send-email 2.17.1 X-FB-Internal: Safe MIME-Version: 1.0 Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-07-24_08:,, signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1907240232 X-FB-Internal: deliver Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Despite a proper NULL-termination after strncpy(..., ..., IFNAMSIZ - 1), GCC8 still complains about *expected* string truncation: xsk.c:330:2: error: 'strncpy' output may be truncated copying 15 bytes from a string of length 15 [-Werror=stringop-truncation] strncpy(ifr.ifr_name, xsk->ifname, IFNAMSIZ - 1); This patch gets rid of the issue altogether by using memcpy instead. There is no performance regression, as strncpy will still copy and fill all of the bytes anyway. v1->v2: - rebase against bpf tree. Cc: Magnus Karlsson Signed-off-by: Andrii Nakryiko Acked-by: Magnus Karlsson Acked-by: Song Liu --- tools/lib/bpf/xsk.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c index e02025bbe36d..680e63066cf3 100644 --- a/tools/lib/bpf/xsk.c +++ b/tools/lib/bpf/xsk.c @@ -326,7 +326,7 @@ static int xsk_get_max_queues(struct xsk_socket *xsk) return -errno; ifr.ifr_data = (void *)&channels; - strncpy(ifr.ifr_name, xsk->ifname, IFNAMSIZ - 1); + memcpy(ifr.ifr_name, xsk->ifname, IFNAMSIZ - 1); ifr.ifr_name[IFNAMSIZ - 1] = '\0'; err = ioctl(fd, SIOCETHTOOL, &ifr); if (err && errno != EOPNOTSUPP) { @@ -516,7 +516,7 @@ int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname, err = -errno; goto out_socket; } - strncpy(xsk->ifname, ifname, IFNAMSIZ - 1); + memcpy(xsk->ifname, ifname, IFNAMSIZ - 1); xsk->ifname[IFNAMSIZ - 1] = '\0'; err = xsk_set_xdp_socket_config(&xsk->config, usr_config); -- 2.17.1