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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 B124AC433E0 for ; Mon, 29 Jun 2020 20:18:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9416E2065D for ; Mon, 29 Jun 2020 20:18:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593461905; bh=qCZoqYSe8toqmTwpU/7R4nE3J3AyzDYI0LJfEu0k/jY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=B99ZhjDVIdcYIpb/nQYV+aaAp6s1B+YTnV/DY70WNH51i70dcOOhslBRCsKERVGyQ R1gA5xwjw/plIENd1KN6yVrfxL3cTxboOLjdsSoQiSu1pq38KSXo4zGm1jOVVDP45J 7Q7p6JuQeFT4hVmb6+u0zsjoTKqAhxxS+wRnGwKI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387651AbgF2USS (ORCPT ); Mon, 29 Jun 2020 16:18:18 -0400 Received: from mail.kernel.org ([198.145.29.99]:37024 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732643AbgF2TZl (ORCPT ); Mon, 29 Jun 2020 15:25:41 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id AEDFA25433; Mon, 29 Jun 2020 15:43:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593445384; bh=qCZoqYSe8toqmTwpU/7R4nE3J3AyzDYI0LJfEu0k/jY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eUKM/ht3iufpi0aCecesrU3UHLuGe6xp25GdQGqJKKVHCpb7uhcX5zNRRVsEXhxwr BKlvKJ9oUsLhUkquIlm/OkoamftM0S2FBHnZSO/MueBKPrXmNL7OTUtnTR/WS6NF99 iWSGy+l6U+WnOQh1q+nzOLmgZbJ1foCXBfkem/ow= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Taehee Yoo , Eric Dumazet , "David S . Miller" , Greg Kroah-Hartman Subject: [PATCH 4.9 138/191] ip_tunnel: fix use-after-free in ip_tunnel_lookup() Date: Mon, 29 Jun 2020 11:39:14 -0400 Message-Id: <20200629154007.2495120-139-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200629154007.2495120-1-sashal@kernel.org> References: <20200629154007.2495120-1-sashal@kernel.org> MIME-Version: 1.0 X-KernelTest-Patch: http://kernel.org/pub/linux/kernel/v4.x/stable-review/patch-4.9.229-rc1.gz X-KernelTest-Tree: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git X-KernelTest-Branch: linux-4.9.y X-KernelTest-Patches: git://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git X-KernelTest-Version: 4.9.229-rc1 X-KernelTest-Deadline: 2020-07-01T15:39+00:00 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Taehee Yoo [ Upstream commit ba61539c6ae57f4146284a5cb4f7b7ed8d42bf45 ] In the datapath, the ip_tunnel_lookup() is used and it internally uses fallback tunnel device pointer, which is fb_tunnel_dev. This pointer variable should be set to NULL when a fb interface is deleted. But there is no routine to set fb_tunnel_dev pointer to NULL. So, this pointer will be still used after interface is deleted and it eventually results in the use-after-free problem. Test commands: ip netns add A ip netns add B ip link add eth0 type veth peer name eth1 ip link set eth0 netns A ip link set eth1 netns B ip netns exec A ip link set lo up ip netns exec A ip link set eth0 up ip netns exec A ip link add gre1 type gre local 10.0.0.1 \ remote 10.0.0.2 ip netns exec A ip link set gre1 up ip netns exec A ip a a 10.0.100.1/24 dev gre1 ip netns exec A ip a a 10.0.0.1/24 dev eth0 ip netns exec B ip link set lo up ip netns exec B ip link set eth1 up ip netns exec B ip link add gre1 type gre local 10.0.0.2 \ remote 10.0.0.1 ip netns exec B ip link set gre1 up ip netns exec B ip a a 10.0.100.2/24 dev gre1 ip netns exec B ip a a 10.0.0.2/24 dev eth1 ip netns exec A hping3 10.0.100.2 -2 --flood -d 60000 & ip netns del B Splat looks like: [ 77.793450][ C3] ================================================================== [ 77.794702][ C3] BUG: KASAN: use-after-free in ip_tunnel_lookup+0xcc4/0xf30 [ 77.795573][ C3] Read of size 4 at addr ffff888060bd9c84 by task hping3/2905 [ 77.796398][ C3] [ 77.796664][ C3] CPU: 3 PID: 2905 Comm: hping3 Not tainted 5.8.0-rc1+ #616 [ 77.797474][ C3] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 [ 77.798453][ C3] Call Trace: [ 77.798815][ C3] [ 77.799142][ C3] dump_stack+0x9d/0xdb [ 77.799605][ C3] print_address_description.constprop.7+0x2cc/0x450 [ 77.800365][ C3] ? ip_tunnel_lookup+0xcc4/0xf30 [ 77.800908][ C3] ? ip_tunnel_lookup+0xcc4/0xf30 [ 77.801517][ C3] ? ip_tunnel_lookup+0xcc4/0xf30 [ 77.802145][ C3] kasan_report+0x154/0x190 [ 77.802821][ C3] ? ip_tunnel_lookup+0xcc4/0xf30 [ 77.803503][ C3] ip_tunnel_lookup+0xcc4/0xf30 [ 77.804165][ C3] __ipgre_rcv+0x1ab/0xaa0 [ip_gre] [ 77.804862][ C3] ? rcu_read_lock_sched_held+0xc0/0xc0 [ 77.805621][ C3] gre_rcv+0x304/0x1910 [ip_gre] [ 77.806293][ C3] ? lock_acquire+0x1a9/0x870 [ 77.806925][ C3] ? gre_rcv+0xfe/0x354 [gre] [ 77.807559][ C3] ? erspan_xmit+0x2e60/0x2e60 [ip_gre] [ 77.808305][ C3] ? rcu_read_lock_sched_held+0xc0/0xc0 [ 77.809032][ C3] ? rcu_read_lock_held+0x90/0xa0 [ 77.809713][ C3] gre_rcv+0x1b8/0x354 [gre] [ ... ] Suggested-by: Eric Dumazet Fixes: c54419321455 ("GRE: Refactor GRE tunneling code.") Signed-off-by: Taehee Yoo Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/ip_tunnel.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c index dd5db4cc7d066..5f2e3334cccec 100644 --- a/net/ipv4/ip_tunnel.c +++ b/net/ipv4/ip_tunnel.c @@ -98,9 +98,10 @@ struct ip_tunnel *ip_tunnel_lookup(struct ip_tunnel_net *itn, __be32 remote, __be32 local, __be32 key) { - unsigned int hash; struct ip_tunnel *t, *cand = NULL; struct hlist_head *head; + struct net_device *ndev; + unsigned int hash; hash = ip_tunnel_hash(key, remote); head = &itn->tunnels[hash]; @@ -175,8 +176,9 @@ struct ip_tunnel *ip_tunnel_lookup(struct ip_tunnel_net *itn, if (t) return t; - if (itn->fb_tunnel_dev && itn->fb_tunnel_dev->flags & IFF_UP) - return netdev_priv(itn->fb_tunnel_dev); + ndev = READ_ONCE(itn->fb_tunnel_dev); + if (ndev && ndev->flags & IFF_UP) + return netdev_priv(ndev); return NULL; } @@ -1193,9 +1195,9 @@ void ip_tunnel_uninit(struct net_device *dev) struct ip_tunnel_net *itn; itn = net_generic(net, tunnel->ip_tnl_net_id); - /* fb_tunnel_dev will be unregisted in net-exit call. */ - if (itn->fb_tunnel_dev != dev) - ip_tunnel_del(itn, netdev_priv(dev)); + ip_tunnel_del(itn, netdev_priv(dev)); + if (itn->fb_tunnel_dev == dev) + WRITE_ONCE(itn->fb_tunnel_dev, NULL); dst_cache_reset(&tunnel->dst_cache); } -- 2.25.1