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=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 23F55C4321D for ; Mon, 20 Aug 2018 02:52:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D38D820C0C for ; Mon, 20 Aug 2018 02:52:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D38D820C0C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=cmss.chinamobile.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726318AbeHTGFM (ORCPT ); Mon, 20 Aug 2018 02:05:12 -0400 Received: from cmccmta1.chinamobile.com ([221.176.66.79]:2095 "EHLO cmccmta1.chinamobile.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725926AbeHTGFM (ORCPT ); Mon, 20 Aug 2018 02:05:12 -0400 Received: from spf.mail.chinamobile.com (unknown[172.16.121.1]) by rmmx-syy-dmz-app03-12003 (RichMail) with SMTP id 2ee35b7a2ca8988-63227; Mon, 20 Aug 2018 10:51:20 +0800 (CST) X-RM-TRANSID: 2ee35b7a2ca8988-63227 X-RM-TagInfo: emlType=0 X-RM-SPAM-FLAG: 00000000 Received: from localhost (unknown[223.105.0.240]) by rmsmtp-syy-appsvr01-12001 (RichMail) with SMTP id 2ee15b7a2ca7dd7-0d6f5; Mon, 20 Aug 2018 10:51:20 +0800 (CST) X-RM-TRANSID: 2ee15b7a2ca7dd7-0d6f5 From: Haishuang Yan To: Steffen Klassert , "David S. Miller" , Alexey Kuznetsov Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Haishuang Yan Subject: [PATCH] ip6_vti: fix a null pointer deference when destroy vti6 tunnel Date: Mon, 20 Aug 2018 10:51:05 +0800 Message-Id: <1534733465-2493-1-git-send-email-yanhaishuang@cmss.chinamobile.com> X-Mailer: git-send-email 1.8.3.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If load ip6_vti module and create a network namespace when set fb_tunnels_only_for_init_net to 1, then exit the namespace will cause following crash: [ 6601.677036] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 [ 6601.679057] PGD 8000000425eca067 P4D 8000000425eca067 PUD 424292067 PMD 0 [ 6601.680483] Oops: 0000 [#1] SMP PTI [ 6601.681223] CPU: 7 PID: 93 Comm: kworker/u16:1 Kdump: loaded Tainted: G E 4.18.0+ #3 [ 6601.683153] Hardware name: Fedora Project OpenStack Nova, BIOS seabios-1.7.5-11.el7 04/01/2014 [ 6601.684919] Workqueue: netns cleanup_net [ 6601.685742] RIP: 0010:vti6_exit_batch_net+0x87/0xd0 [ip6_vti] [ 6601.686932] Code: 7b 08 48 89 e6 e8 b9 ea d3 dd 48 8b 1b 48 85 db 75 ec 48 83 c5 08 48 81 fd 00 01 00 00 75 d5 49 8b 84 24 08 01 00 00 48 89 e6 <48> 8b 78 08 e8 90 ea d3 dd 49 8b 45 28 49 39 c6 4c 8d 68 d8 75 a1 [ 6601.690735] RSP: 0018:ffffa897c2737de0 EFLAGS: 00010246 [ 6601.691846] RAX: 0000000000000000 RBX: 0000000000000000 RCX: dead000000000200 [ 6601.693324] RDX: 0000000000000015 RSI: ffffa897c2737de0 RDI: ffffffff9f2ea9e0 [ 6601.694824] RBP: 0000000000000100 R08: 0000000000000000 R09: 0000000000000000 [ 6601.696314] R10: 0000000000000001 R11: 0000000000000000 R12: ffff8dc323c07e00 [ 6601.697812] R13: ffff8dc324a63100 R14: ffffa897c2737e30 R15: ffffa897c2737e30 [ 6601.699345] FS: 0000000000000000(0000) GS:ffff8dc33fdc0000(0000) knlGS:0000000000000000 [ 6601.701068] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 6601.702282] CR2: 0000000000000008 CR3: 0000000424966002 CR4: 00000000001606e0 [ 6601.703791] Call Trace: [ 6601.704329] cleanup_net+0x1b4/0x2c0 [ 6601.705268] process_one_work+0x16c/0x370 [ 6601.706145] worker_thread+0x49/0x3e0 [ 6601.706942] kthread+0xf8/0x130 [ 6601.707626] ? rescuer_thread+0x340/0x340 [ 6601.708476] ? kthread_bind+0x10/0x10 [ 6601.709266] ret_from_fork+0x35/0x40 Reproduce: modprobe ip6_vti echo 1 > /proc/sys/net/core/fb_tunnels_only_for_init_net unshare -n exit This because ip6n->tnls_wc[0] point to fallback device in default, but in non-default namespace, ip6n->tnls_wc[0] will be NULL, so add the NULL check comparatively. Fixes: e2948e5af8ee ("ip6_vti: fix creating fallback tunnel device for vti6") Signed-off-by: Haishuang Yan --- net/ipv6/ip6_vti.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/ipv6/ip6_vti.c b/net/ipv6/ip6_vti.c index 38dec9d..5095367 100644 --- a/net/ipv6/ip6_vti.c +++ b/net/ipv6/ip6_vti.c @@ -1094,7 +1094,8 @@ static void __net_exit vti6_destroy_tunnels(struct vti6_net *ip6n, } t = rtnl_dereference(ip6n->tnls_wc[0]); - unregister_netdevice_queue(t->dev, list); + if (t) + unregister_netdevice_queue(t->dev, list); } static int __net_init vti6_init_net(struct net *net) -- 1.8.3.1