From patchwork Thu Apr 20 12:40:35 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Ziyang Xuan (William)" X-Patchwork-Id: 13218727 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0FA98C77B73 for ; Thu, 20 Apr 2023 12:41:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231819AbjDTMlS (ORCPT ); Thu, 20 Apr 2023 08:41:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34824 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231715AbjDTMlR (ORCPT ); Thu, 20 Apr 2023 08:41:17 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E02666A48 for ; Thu, 20 Apr 2023 05:40:41 -0700 (PDT) Received: from canpemm500006.china.huawei.com (unknown [172.30.72.55]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4Q2HG73p4HzSsLF; Thu, 20 Apr 2023 20:36:31 +0800 (CST) Received: from localhost.localdomain (10.175.104.82) by canpemm500006.china.huawei.com (7.192.105.130) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.23; Thu, 20 Apr 2023 20:40:39 +0800 From: Ziyang Xuan To: , , , , , , Subject: [PATCH net v3] ipv4: Fix potential uninit variable access bug in __ip_make_skb() Date: Thu, 20 Apr 2023 20:40:35 +0800 Message-ID: <20230420124035.2061588-1-william.xuanziyang@huawei.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-Originating-IP: [10.175.104.82] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To canpemm500006.china.huawei.com (7.192.105.130) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org Like commit ea30388baebc ("ipv6: Fix an uninit variable access bug in __ip6_make_skb()"). icmphdr does not in skb linear region under the scenario of SOCK_RAW socket. Access icmp_hdr(skb)->type directly will trigger the uninit variable access bug. Use a local variable icmp_type to carry the correct value in different scenarios. Fixes: 96793b482540 ("[IPV4]: Add ICMPMsgStats MIB (RFC 4293)") Reviewed-by: Willem de Bruijn Signed-off-by: Ziyang Xuan --- v3: - Fix misspell from "buf" to "bug". - Add comments for changes. - Add Reviewed-by tag. v2: - Use sk->sk_type not sk->sk_socket->type. --- net/ipv4/ip_output.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index 4e4e308c3230..89bd7872c629 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -1570,9 +1570,19 @@ struct sk_buff *__ip_make_skb(struct sock *sk, cork->dst = NULL; skb_dst_set(skb, &rt->dst); - if (iph->protocol == IPPROTO_ICMP) - icmp_out_count(net, ((struct icmphdr *) - skb_transport_header(skb))->type); + if (iph->protocol == IPPROTO_ICMP) { + u8 icmp_type; + + /* For such sockets, transhdrlen is zero when do ip_append_data(), + * so icmphdr does not in skb linear region and can not get icmp_type + * by icmp_hdr(skb)->type. + */ + if (sk->sk_type == SOCK_RAW && !inet_sk(sk)->hdrincl) + icmp_type = fl4->fl4_icmp_type; + else + icmp_type = icmp_hdr(skb)->type; + icmp_out_count(net, icmp_type); + } ip_cork_release(cork); out: