From patchwork Tue Jun 16 16:01:53 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Taehee Yoo X-Patchwork-Id: 1310560 X-Patchwork-Delegate: davem@davemloft.net 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=gmail.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20161025 header.b=dkh2Fvfw; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 49mXyV55nbzB3t3 for ; Wed, 17 Jun 2020 02:02:10 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733179AbgFPQCI (ORCPT ); Tue, 16 Jun 2020 12:02:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48730 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732840AbgFPQCD (ORCPT ); Tue, 16 Jun 2020 12:02:03 -0400 Received: from mail-pj1-x1042.google.com (mail-pj1-x1042.google.com [IPv6:2607:f8b0:4864:20::1042]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AF7D7C061573 for ; Tue, 16 Jun 2020 09:02:03 -0700 (PDT) Received: by mail-pj1-x1042.google.com with SMTP id ga6so1646564pjb.1 for ; Tue, 16 Jun 2020 09:02:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=yvH4tKpCIZN3i9yS1tqHno2lbmWIQ0tG2BKc67c2Fi0=; b=dkh2FvfwAgAG9DVEIzRDHxXwG1ZCmSDYbOG1wYoka7DYG4jS9aBNnoY4Uy3fqBvaNb d1yd1l6fnoNpMQvfWThWeVxDa6LAp7LkXXbmOGPNNpKy84OnJ68uCOrV4VVe/MWnsT6C 3OjOvuYAuI3JNz6kYSe5G3IYUe6gedzOcg7o2JhTi7wbeKPSjuNhNc1EoyKmApLWs7Ll iIOziINQyo8wWGfirntAhsZVHtEd4IL+Nvz33/PDftgogv9AhJK3UBm0NdV3ERJ07Ng7 xQ+Nb8n3niLB1NPB2/eDZmmgzF/Bx77rQGOGpANW1H28H6ktnBr7HMOjNpj1zL57yDRD 2BVw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=yvH4tKpCIZN3i9yS1tqHno2lbmWIQ0tG2BKc67c2Fi0=; b=H++K8x+qAR5Rv2XIHbX6uvdjl740QQqf362XUXGELd4bdV/oydORKFEl3Ieqlc1TTx zzaj8+hRcoInDj3lgosssGKPmq9QIKT1dpOLWOHlde3F1ZiiXifbEDSVBwNPmQkdSfqT O34ibhEotkZa8WEUVGNVLB3XXRBa81/+lfMwOQ2Kzrn/ljJvVPas/G1oaLKrBY1O7beU F9TZKe/7Xo/EmdMHKolHI8lMug/nLIVh1w+Oi0EJVLT0TrDkNC2SrAMhP3o5Fq1fC9Db N1eX1rsVlzoyOQ4xkujVNzaU5vsfa6MaDumFazIbjc9gVUBK1vOgdmRSWZBbu9zcakEa /elg== X-Gm-Message-State: AOAM5326N/05nUTBZdBc5ESm7nNHXFg5NrbOTttqXJuLE07xxmvdcH1D /5XvlrokRBNzeqozq6lKVxM= X-Google-Smtp-Source: ABdhPJw/tis8qkh8fsnZQ3cu5zw37knAm1uXa8hUzSxpwXpf5Z//UASeYhVSsl7CXY85lridcYIgfQ== X-Received: by 2002:a17:90a:1781:: with SMTP id q1mr3912636pja.8.1592323321549; Tue, 16 Jun 2020 09:02:01 -0700 (PDT) Received: from localhost.localdomain ([180.70.143.152]) by smtp.gmail.com with ESMTPSA id ds11sm2928309pjb.0.2020.06.16.09.01.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 16 Jun 2020 09:02:00 -0700 (PDT) From: Taehee Yoo To: davem@davemloft.net, kuba@kernel.org, netdev@vger.kernel.org Cc: ap420073@gmail.com, pshelar@nicira.com, eric.dumazet@gmail.com Subject: [PATCH net v2] ip_tunnel: fix use-after-free in ip_tunnel_lookup() Date: Tue, 16 Jun 2020 16:01:53 +0000 Message-Id: <20200616160153.8479-1-ap420073@gmail.com> X-Mailer: git-send-email 2.17.1 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 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: [ 133.319668][ C3] BUG: KASAN: use-after-free in ip_tunnel_lookup+0x9d6/0xde0 [ 133.343852][ C3] Read of size 4 at addr ffff8880b1701c84 by task hping3/1222 [ 133.344724][ C3] [ 133.345002][ C3] CPU: 3 PID: 1222 Comm: hping3 Not tainted 5.7.0+ #591 [ 133.345814][ C3] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 [ 133.373336][ C3] Call Trace: [ 133.374792][ C3] [ 133.375205][ C3] dump_stack+0x96/0xdb [ 133.375789][ C3] print_address_description.constprop.6+0x2cc/0x450 [ 133.376720][ C3] ? ip_tunnel_lookup+0x9d6/0xde0 [ 133.377431][ C3] ? ip_tunnel_lookup+0x9d6/0xde0 [ 133.378130][ C3] ? ip_tunnel_lookup+0x9d6/0xde0 [ 133.378851][ C3] kasan_report+0x154/0x190 [ 133.379494][ C3] ? ip_tunnel_lookup+0x9d6/0xde0 [ 133.380200][ C3] ip_tunnel_lookup+0x9d6/0xde0 [ 133.380894][ C3] __ipgre_rcv+0x1ab/0xaa0 [ip_gre] [ 133.381630][ C3] ? rcu_read_lock_sched_held+0xc0/0xc0 [ 133.382429][ C3] gre_rcv+0x304/0x1910 [ip_gre] [ ... ] Suggested-by: Eric Dumazet Fixes: c54419321455 ("GRE: Refactor GRE tunneling code.") Signed-off-by: Taehee Yoo --- v1 -> v2: - Do not add a new variable. net/ipv4/ip_tunnel.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c index f4f1d11eab50..701f150f11e1 100644 --- a/net/ipv4/ip_tunnel.c +++ b/net/ipv4/ip_tunnel.c @@ -85,9 +85,10 @@ 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]; @@ -162,8 +163,9 @@ struct ip_tunnel *ip_tunnel_lookup(struct ip_tunnel_net *itn, if (t && t->dev->flags & IFF_UP) 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; } @@ -1260,8 +1262,9 @@ void ip_tunnel_uninit(struct net_device *dev) 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); }