[BR_NETFILTER]: Fix leak if skb traverses > 1 bridge

Call nf_bridge_put() before allocating a new nf_bridge structure and
potentially overwriting the pointer to a previously allocated one.
This fixes a memory leak which can occur when the bridge topology
allows for an skb to traverse more than one bridge.

Signed-off-by: David Kimdon <david.kimdon@devicescape.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c
index 43a0b35dfe6f7acf7c33f64e3bf3b0569b35f04c..23422bd53a5e04192d9f452ed3bd36cd0f54ac71 100644 (file)
--- a/net/bridge/br_netfilter.c
+++ b/net/bridge/br_netfilter.c
@@ -369,6 +369,7 @@ static unsigned int br_nf_pre_routing_ipv6(unsigned int hook,
        if (hdr->nexthdr == NEXTHDR_HOP && check_hbh_len(skb))
                        goto inhdr_error;
 
+       nf_bridge_put(skb->nf_bridge);
        if ((nf_bridge = nf_bridge_alloc(skb)) == NULL)
                return NF_DROP;
        setup_pre_routing(skb);
@@ -452,6 +453,7 @@ static unsigned int br_nf_pre_routing(unsigned int hook, struct sk_buff **pskb,
                        skb->ip_summed = CHECKSUM_NONE;
        }
 
+       nf_bridge_put(skb->nf_bridge);
        if ((nf_bridge = nf_bridge_alloc(skb)) == NULL)
                return NF_DROP;
        setup_pre_routing(skb);