From patchwork Thu Dec 3 23:54:40 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 1410702 Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=kernel.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4CnCQq2Rzpz9sSs for ; Fri, 4 Dec 2020 10:56:03 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728901AbgLCXze convert rfc822-to-8bit (ORCPT ); Thu, 3 Dec 2020 18:55:34 -0500 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:14012 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727175AbgLCXzd (ORCPT ); Thu, 3 Dec 2020 18:55:33 -0500 Received: from pps.filterd (m0044010.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 0B3NkgBf003350 for ; Thu, 3 Dec 2020 15:54:52 -0800 Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 357159v8fp-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Thu, 03 Dec 2020 15:54:52 -0800 Received: from intmgw002.03.ash8.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:83::4) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Thu, 3 Dec 2020 15:54:51 -0800 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id D4F062ECA8F6; Thu, 3 Dec 2020 15:54:50 -0800 (PST) From: Andrii Nakryiko To: , , , CC: , Subject: [PATCH bpf-next 2/2] selftests/bpf: fix invalid use of strncat in test_sockmap Date: Thu, 3 Dec 2020 15:54:40 -0800 Message-ID: <20201203235440.2302137-2-andrii@kernel.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20201203235440.2302137-1-andrii@kernel.org> References: <20201203235440.2302137-1-andrii@kernel.org> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.312,18.0.737 definitions=2020-12-03_15:2020-12-03,2020-12-03 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 phishscore=0 mlxlogscore=999 clxscore=1034 lowpriorityscore=0 suspectscore=8 bulkscore=0 spamscore=0 impostorscore=0 mlxscore=0 priorityscore=1501 adultscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2012030131 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org strncat()'s third argument is how many bytes will be added *in addition* to already existing bytes in destination. Plus extra zero byte will be added after that. So existing use in test_sockmap has many opportunities to overflow the string and cause memory corruptions. And in this case, GCC complains for a good reason. Fixes: 16962b2404ac ("bpf: sockmap, add selftests") Fixes: 73563aa3d977 ("selftests/bpf: test_sockmap, print additional test options") Fixes: 1ade9abadfca ("bpf: test_sockmap, add options for msg_pop_data() helper") Fixes: 463bac5f1ca7 ("bpf, selftests: Add test for ktls with skb bpf ingress policy") Fixes: e9dd904708c4 ("bpf: add tls support for testing in test_sockmap") Fixes: 753fb2ee0934 ("bpf: sockmap, add msg_peek tests to test_sockmap") Signed-off-by: Andrii Nakryiko --- tools/testing/selftests/bpf/test_sockmap.c | 36 ++++++++++++++-------- 1 file changed, 23 insertions(+), 13 deletions(-) diff --git a/tools/testing/selftests/bpf/test_sockmap.c b/tools/testing/selftests/bpf/test_sockmap.c index 0fa1e421c3d7..427ca00a3217 100644 --- a/tools/testing/selftests/bpf/test_sockmap.c +++ b/tools/testing/selftests/bpf/test_sockmap.c @@ -1273,6 +1273,16 @@ static char *test_to_str(int test) return "unknown"; } +static void append_str(char *dst, const char *src, size_t dst_cap) +{ + size_t avail = dst_cap - strlen(dst); + + if (avail <= 1) /* just zero byte could be written */ + return; + + strncat(dst, src, avail - 1); /* strncat() adds + 1 for zero byte */ +} + #define OPTSTRING 60 static void test_options(char *options) { @@ -1281,42 +1291,42 @@ static void test_options(char *options) memset(options, 0, OPTSTRING); if (txmsg_pass) - strncat(options, "pass,", OPTSTRING); + append_str(options, "pass,", OPTSTRING); if (txmsg_redir) - strncat(options, "redir,", OPTSTRING); + append_str(options, "redir,", OPTSTRING); if (txmsg_drop) - strncat(options, "drop,", OPTSTRING); + append_str(options, "drop,", OPTSTRING); if (txmsg_apply) { snprintf(tstr, OPTSTRING, "apply %d,", txmsg_apply); - strncat(options, tstr, OPTSTRING); + append_str(options, tstr, OPTSTRING); } if (txmsg_cork) { snprintf(tstr, OPTSTRING, "cork %d,", txmsg_cork); - strncat(options, tstr, OPTSTRING); + append_str(options, tstr, OPTSTRING); } if (txmsg_start) { snprintf(tstr, OPTSTRING, "start %d,", txmsg_start); - strncat(options, tstr, OPTSTRING); + append_str(options, tstr, OPTSTRING); } if (txmsg_end) { snprintf(tstr, OPTSTRING, "end %d,", txmsg_end); - strncat(options, tstr, OPTSTRING); + append_str(options, tstr, OPTSTRING); } if (txmsg_start_pop) { snprintf(tstr, OPTSTRING, "pop (%d,%d),", txmsg_start_pop, txmsg_start_pop + txmsg_pop); - strncat(options, tstr, OPTSTRING); + append_str(options, tstr, OPTSTRING); } if (txmsg_ingress) - strncat(options, "ingress,", OPTSTRING); + append_str(options, "ingress,", OPTSTRING); if (txmsg_redir_skb) - strncat(options, "redir_skb,", OPTSTRING); + append_str(options, "redir_skb,", OPTSTRING); if (txmsg_ktls_skb) - strncat(options, "ktls_skb,", OPTSTRING); + append_str(options, "ktls_skb,", OPTSTRING); if (ktls) - strncat(options, "ktls,", OPTSTRING); + append_str(options, "ktls,", OPTSTRING); if (peek_flag) - strncat(options, "peek,", OPTSTRING); + append_str(options, "peek,", OPTSTRING); } static int __test_exec(int cgrp, int test, struct sockmap_options *opt)