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authorPatrick McHardy <kaber@trash.net>2008-01-29 19:08:28 +0100
committerGreg Kroah-Hartman <gregkh@suse.de>2008-02-08 12:01:49 -0800
commit50b85eb6699dac080b5047034da19c7282c821f2 (patch)
tree86b2ba682329d5a5c5311867f7d4e049c07e674b
parent418b48ea165b0b03652c85436807ac6760838c21 (diff)
Netfilter: bridge-netfilter: fix net_device refcnt leaks
[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 <hesso@pool.math.tu-berlin.de>. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--net/bridge/br_netfilter.c27
1 files changed, 27 insertions, 0 deletions
diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c
index ce48d8cb98e0..22545bd572ca 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;