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=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 BFE77C433E0 for ; Fri, 29 May 2020 11:10:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AB36E206E2 for ; Fri, 29 May 2020 11:10:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726883AbgE2LK5 (ORCPT ); Fri, 29 May 2020 07:10:57 -0400 Received: from a.mx.secunet.com ([62.96.220.36]:39916 "EHLO a.mx.secunet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726518AbgE2LKo (ORCPT ); Fri, 29 May 2020 07:10:44 -0400 Received: from localhost (localhost [127.0.0.1]) by a.mx.secunet.com (Postfix) with ESMTP id C83AA205B4; Fri, 29 May 2020 13:10:42 +0200 (CEST) X-Virus-Scanned: by secunet Received: from a.mx.secunet.com ([127.0.0.1]) by localhost (a.mx.secunet.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id UqrnWa_JtOon; Fri, 29 May 2020 13:10:42 +0200 (CEST) Received: from mail-essen-01.secunet.de (mail-essen-01.secunet.de [10.53.40.204]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by a.mx.secunet.com (Postfix) with ESMTPS id 12C09205AE; Fri, 29 May 2020 13:10:42 +0200 (CEST) Received: from mbx-essen-01.secunet.de (10.53.40.197) by mail-essen-01.secunet.de (10.53.40.204) with Microsoft SMTP Server (TLS) id 14.3.487.0; Fri, 29 May 2020 13:10:41 +0200 Received: from gauss2.secunet.de (10.182.7.193) by mbx-essen-01.secunet.de (10.53.40.197) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Fri, 29 May 2020 13:10:40 +0200 Received: by gauss2.secunet.de (Postfix, from userid 1000) id 4C704318076F; Fri, 29 May 2020 13:04:12 +0200 (CEST) From: Steffen Klassert To: David Miller CC: Herbert Xu , Steffen Klassert , Subject: [PATCH 15/15] xfrm: fix a NULL-ptr deref in xfrm_local_error Date: Fri, 29 May 2020 13:04:08 +0200 Message-ID: <20200529110408.6349-16-steffen.klassert@secunet.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200529110408.6349-1-steffen.klassert@secunet.com> References: <20200529110408.6349-1-steffen.klassert@secunet.com> MIME-Version: 1.0 Content-Type: text/plain X-ClientProxiedBy: cas-essen-01.secunet.de (10.53.40.201) To mbx-essen-01.secunet.de (10.53.40.197) X-EXCLAIMER-MD-CONFIG: 2c86f778-e09b-4440-8b15-867914633a10 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Xin Long This patch is to fix a crash: [ ] kasan: GPF could be caused by NULL-ptr deref or user memory access [ ] general protection fault: 0000 [#1] SMP KASAN PTI [ ] RIP: 0010:ipv6_local_error+0xac/0x7a0 [ ] Call Trace: [ ] xfrm6_local_error+0x1eb/0x300 [ ] xfrm_local_error+0x95/0x130 [ ] __xfrm6_output+0x65f/0xb50 [ ] xfrm6_output+0x106/0x46f [ ] udp_tunnel6_xmit_skb+0x618/0xbf0 [ip6_udp_tunnel] [ ] vxlan_xmit_one+0xbc6/0x2c60 [vxlan] [ ] vxlan_xmit+0x6a0/0x4276 [vxlan] [ ] dev_hard_start_xmit+0x165/0x820 [ ] __dev_queue_xmit+0x1ff0/0x2b90 [ ] ip_finish_output2+0xd3e/0x1480 [ ] ip_do_fragment+0x182d/0x2210 [ ] ip_output+0x1d0/0x510 [ ] ip_send_skb+0x37/0xa0 [ ] raw_sendmsg+0x1b4c/0x2b80 [ ] sock_sendmsg+0xc0/0x110 This occurred when sending a v4 skb over vxlan6 over ipsec, in which case skb->protocol == htons(ETH_P_IPV6) while skb->sk->sk_family == AF_INET in xfrm_local_error(). Then it will go to xfrm6_local_error() where it tries to get ipv6 info from a ipv4 sk. This issue was actually fixed by Commit 628e341f319f ("xfrm: make local error reporting more robust"), but brought back by Commit 844d48746e4b ("xfrm: choose protocol family by skb protocol"). So to fix it, we should call xfrm6_local_error() only when skb->protocol is htons(ETH_P_IPV6) and skb->sk->sk_family is AF_INET6. Fixes: 844d48746e4b ("xfrm: choose protocol family by skb protocol") Reported-by: Xiumei Mu Signed-off-by: Xin Long Signed-off-by: Steffen Klassert --- net/xfrm/xfrm_output.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/xfrm/xfrm_output.c b/net/xfrm/xfrm_output.c index 69c33cab8f49..69c4900db817 100644 --- a/net/xfrm/xfrm_output.c +++ b/net/xfrm/xfrm_output.c @@ -642,7 +642,8 @@ void xfrm_local_error(struct sk_buff *skb, int mtu) if (skb->protocol == htons(ETH_P_IP)) proto = AF_INET; - else if (skb->protocol == htons(ETH_P_IPV6)) + else if (skb->protocol == htons(ETH_P_IPV6) && + skb->sk->sk_family == AF_INET6) proto = AF_INET6; else return; -- 2.17.1