From patchwork Thu Mar 27 20:27:58 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vlad Yasevich X-Patchwork-Id: 334459 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id E9493140094 for ; Fri, 28 Mar 2014 07:28:14 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757269AbaC0U2J (ORCPT ); Thu, 27 Mar 2014 16:28:09 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55071 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757057AbaC0U2H (ORCPT ); Thu, 27 Mar 2014 16:28:07 -0400 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s2RKS3Gr002412 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Thu, 27 Mar 2014 16:28:04 -0400 Received: from vyasevic.redhat.com (ovpn-113-95.phx2.redhat.com [10.3.113.95]) by int-mx14.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id s2RKS1jD006334; Thu, 27 Mar 2014 16:28:02 -0400 From: Vlad Yasevich To: netdev@vger.kernel.org Cc: bridge@lists.linux-foundation.org, Vlad Yasevich , Toshiaki Makita Subject: [PATCH] bridge: Fix crash with vlan filtering and tcpdump Date: Thu, 27 Mar 2014 16:27:58 -0400 Message-Id: <1395952078-16266-1-git-send-email-vyasevic@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.27 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org When the vlan filtering is enabled on the bridge, but the filter is not configured on the bridge device itself, running tcpdump on the bridge device will result in a an Oops with NULL pointer dereference. The reason is that br_pass_frame_up() will bypass the vlan check because promisc flag is set. It will then try to get the table pointer and process the packet based on the table. Since the table pointer is NULL, we oops. Catch this special condition in br_handle_vlan(). Reported-by: Toshiaki Makita CC: Toshiaki Makita Signed-off-by: Vlad Yasevich --- * Changed to use kfree_skb() instead of kfree_skb_list() to match the reset of bridge code. net/bridge/br_input.c | 11 ++++++----- net/bridge/br_vlan.c | 14 ++++++++++++++ 2 files changed, 20 insertions(+), 5 deletions(-) diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c index 28d5446..d0cca3c 100644 --- a/net/bridge/br_input.c +++ b/net/bridge/br_input.c @@ -29,6 +29,7 @@ static int br_pass_frame_up(struct sk_buff *skb) struct net_device *indev, *brdev = BR_INPUT_SKB_CB(skb)->brdev; struct net_bridge *br = netdev_priv(brdev); struct pcpu_sw_netstats *brstats = this_cpu_ptr(br->stats); + struct net_port_vlans *pv; u64_stats_update_begin(&brstats->syncp); brstats->rx_packets++; @@ -39,18 +40,18 @@ static int br_pass_frame_up(struct sk_buff *skb) * packet is allowed except in promisc modue when someone * may be running packet capture. */ + pv = br_get_vlan_info(br); if (!(brdev->flags & IFF_PROMISC) && - !br_allowed_egress(br, br_get_vlan_info(br), skb)) { + !br_allowed_egress(br, pv, skb)) { kfree_skb(skb); return NET_RX_DROP; } - skb = br_handle_vlan(br, br_get_vlan_info(br), skb); - if (!skb) - return NET_RX_DROP; - indev = skb->dev; skb->dev = brdev; + skb = br_handle_vlan(br, pv, skb); + if (!skb) + return NET_RX_DROP; return NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, skb, indev, NULL, netif_receive_skb); diff --git a/net/bridge/br_vlan.c b/net/bridge/br_vlan.c index 8249ca7..b153cc4 100644 --- a/net/bridge/br_vlan.c +++ b/net/bridge/br_vlan.c @@ -144,6 +144,20 @@ struct sk_buff *br_handle_vlan(struct net_bridge *br, if (!br->vlan_enabled) goto out; + /* Vlan filter table must be configured at this point. The + * only exception is the bridge is set in promisc mode and the + * packet is destined for the bridge device. In this case + * pass the packet as is. + */ + if (!pv) { + if ((br->dev->flags & IFF_PROMISC) && skb->dev == br->dev) + goto out; + else { + kfree_skb(skb); + return NULL; + } + } + /* At this point, we know that the frame was filtered and contains * a valid vlan id. If the vlan id is set in the untagged bitmap, * send untagged; otherwise, send tagged.