[NETFILTER]: bridge: fix double POSTROUTING hook invocation

Packets routed between bridges have the POST_ROUTING hook invoked
twice since bridging mistakes them for bridged packets because
they have skb->nf_bridge set.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c
index da22f900e89d..c1757c79dfbb 100644
--- a/net/bridge/br_netfilter.c
+++ b/net/bridge/br_netfilter.c
@@ -766,6 +766,9 @@ static unsigned int br_nf_post_routing(unsigned int hook, struct sk_buff *skb,
         if (!nf_bridge)
                 return NF_ACCEPT;
 
+        if (!(nf_bridge->mask & (BRNF_BRIDGED | BRNF_BRIDGED_DNAT)))
+                return NF_ACCEPT;
+
         if (!realoutdev)
                 return NF_DROP;