From mboxrd@z Thu Jan 1 00:00:00 1970 From: Patrick McHardy Subject: [NETFILTER -stable 02/02]: bridge-netfilter: fix net_device refcnt leaks Date: Tue, 29 Jan 2008 19:08:28 +0100 Message-ID: <479F6B9C.6000101@trash.net> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="------------000603080504000504010701" Cc: "David S. Miller" , Netfilter Development Mailinglist To: stable@kernel.org Return-path: Received: from stinky.trash.net ([213.144.137.162]:60994 "EHLO stinky.trash.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760624AbYA2SId (ORCPT ); Tue, 29 Jan 2008 13:08:33 -0500 Sender: netfilter-devel-owner@vger.kernel.org List-ID: This is a multi-part message in MIME format. --------------000603080504000504010701 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit --------------000603080504000504010701 Content-Type: text/x-patch; name="02.diff" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="02.diff" commit 6738b41be08760572a3fd013c57b4554de0080f5 Author: Patrick McHardy Date: Tue Jan 29 19:02:59 2008 +0100 [NETFILTER]: bridge-netfilter: fix net_device refcnt leaks Upstream commit 2dc2f207fb251666d2396fe1a69272b307ecc333 When packets are flood-forwarded to multiple output devices, the bridge-netfilter code reuses skb->nf_bridge for each clone to store the bridge port. When queueing packets using NFQUEUE netfilter takes a reference to skb->nf_bridge->physoutdev, which is overwritten when the packet is forwarded to the second port. This causes refcount unterflows for the first device and refcount leaks for all others. Additionally this provides incorrect data to the iptables physdev match. Unshare skb->nf_bridge by copying it if it is shared before assigning the physoutdev device. Reported, tested and based on initial patch by Jan Christoph Nordholz . Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c index ce48d8c..22545bd 100644 --- a/net/bridge/br_netfilter.c +++ b/net/bridge/br_netfilter.c @@ -142,6 +142,23 @@ static inline struct nf_bridge_info *nf_bridge_alloc(struct sk_buff *skb) return skb->nf_bridge; } +static inline struct nf_bridge_info *nf_bridge_unshare(struct sk_buff *skb) +{ + struct nf_bridge_info *nf_bridge = skb->nf_bridge; + + if (atomic_read(&nf_bridge->use) > 1) { + struct nf_bridge_info *tmp = nf_bridge_alloc(skb); + + if (tmp) { + memcpy(tmp, nf_bridge, sizeof(struct nf_bridge_info)); + atomic_set(&tmp->use, 1); + nf_bridge_put(nf_bridge); + } + nf_bridge = tmp; + } + return nf_bridge; +} + static inline void nf_bridge_push_encap_header(struct sk_buff *skb) { unsigned int len = nf_bridge_encap_header_len(skb); @@ -644,6 +661,11 @@ static unsigned int br_nf_forward_ip(unsigned int hook, struct sk_buff **pskb, if (!skb->nf_bridge) return NF_ACCEPT; + /* Need exclusive nf_bridge_info since we might have multiple + * different physoutdevs. */ + if (!nf_bridge_unshare(skb)) + return NF_DROP; + parent = bridge_parent(out); if (!parent) return NF_DROP; @@ -727,6 +749,11 @@ static unsigned int br_nf_local_out(unsigned int hook, struct sk_buff **pskb, if (!skb->nf_bridge) return NF_ACCEPT; + /* Need exclusive nf_bridge_info since we might have multiple + * different physoutdevs. */ + if (!nf_bridge_unshare(skb)) + return NF_DROP; + nf_bridge = skb->nf_bridge; if (!(nf_bridge->mask & BRNF_BRIDGED_DNAT)) return NF_ACCEPT; --------------000603080504000504010701--