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,URIBL_BLOCKED, 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 05063C76190 for ; Tue, 23 Jul 2019 22:01:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CFBDE218F0 for ; Tue, 23 Jul 2019 22:01:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="k4zO6Xxb" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389124AbfGWWBj (ORCPT ); Tue, 23 Jul 2019 18:01:39 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:54304 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2392204AbfGWWBj (ORCPT ); Tue, 23 Jul 2019 18:01:39 -0400 Received: from pps.filterd (m0109331.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x6NLqwir020489 for ; Tue, 23 Jul 2019 15:01:37 -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=snnMS8SSyfbrml0K8FCk8qY03YsI+7Yi9witzTC6DkA=; b=k4zO6Xxb1L1z6xzqJ1wyu7IDqWW54vCaPenz+cE2Hx0ZNXTp1W9JRDFAAqnFwfPJMTHo ZyVElFuupC7aSpJWb519ueLRj+GWBTJHjsxSgYRLShgxmZTeYca2S5+Aq7z3yMYnviMQ qP+l0rrL4JioQuyiQXB8QkYGN2kUC0MwpdQ= Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 2tx61316j3-7 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Tue, 23 Jul 2019 15:01:37 -0700 Received: from mx-out.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:82::c) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1713.5; Tue, 23 Jul 2019 15:01:30 -0700 Received: by dev101.prn2.facebook.com (Postfix, from userid 137359) id 423CE8615BA; Tue, 23 Jul 2019 15:01:29 -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 bpf-next] libbpf: silence GCC8 warning about string truncation Date: Tue, 23 Jul 2019 15:01:27 -0700 Message-ID: <20190723220127.1815913-1-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=2019-07-23_09:,, signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 priorityscore=1501 malwarescore=0 suspectscore=8 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-1907230221 X-FB-Internal: deliver Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@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. Cc: Magnus Karlsson Signed-off-by: Andrii Nakryiko --- 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 5007b5d4fd2c..65f5dd556f99 100644 --- a/tools/lib/bpf/xsk.c +++ b/tools/lib/bpf/xsk.c @@ -327,7 +327,7 @@ static int xsk_get_max_queues(struct xsk_socket *xsk) channels.cmd = ETHTOOL_GCHANNELS; 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) { @@ -517,7 +517,7 @@ 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