bridge: provide a mtu() method for fake_dst_ops

Commit 618f9bc74a039da76 (net: Move mtu handling down to the protocol
depended handlers) forgot the bridge netfilter case, adding a NULL
dereference in ip_fragment().

Reported-by: Chris Boot <bootc@bootc.net>
CC: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 0 deletions

diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c
index d6ec3720c77e..08757dc670a4 100644
--- a/net/bridge/br_netfilter.c
+++ b/net/bridge/br_netfilter.c
@@ -114,12 +114,18 @@ static struct neighbour *fake_neigh_lookup(const struct dst_entry *dst, const vo
         return NULL;
 }
 
+static unsigned int fake_mtu(const struct dst_entry *dst)
+{
+        return dst->dev->mtu;
+}
+
 static struct dst_ops fake_dst_ops = {
         .family =               AF_INET,
         .protocol =             cpu_to_be16(ETH_P_IP),
         .update_pmtu =          fake_update_pmtu,
         .cow_metrics =          fake_cow_metrics,
         .neigh_lookup =         fake_neigh_lookup,
+        .mtu =                  fake_mtu,
 };
 
 /*