[BRIDGE]: Unshare skb upon entry

Due to the special location of the bridging hook, it should never see a
shared packet anyway (certainly not with any in-kernel code).  So it
makes sense to unshare the skb there if necessary as that will greatly
simplify the code below it (in particular, netfilter).

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 0 deletions

diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
index 3a8a015c92e0..f8e0a2fa796e 100644
--- a/net/bridge/br_input.c
+++ b/net/bridge/br_input.c
@@ -126,6 +126,10 @@ struct sk_buff *br_handle_frame(struct net_bridge_port *p, struct sk_buff *skb)
         if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
                 goto drop;
 
+        skb = skb_share_check(skb, GFP_ATOMIC);
+        if (!skb)
+                return NULL;
+
         if (unlikely(is_link_local(dest))) {
                 /* Pause frames shouldn't be passed up by driver anyway */
                 if (skb->protocol == htons(ETH_P_PAUSE))