[PATCH] macvlan: fix a possible use after free

Commit bc416d9768 (macvlan: handle fragmented multicast frames) added a
possible use after free in macvlan_handle_frame(), since
ip_check_defrag() uses pskb_may_pull() : skb header can be reallocated.

Signed-off-by: Eric Dumazet <redacted>
Cc: Ben Greear <redacted>
---
 drivers/net/macvlan.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index f2f820c..9ea9921 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c

@@ -173,6 +173,7 @@ static rx_handler_result_t macvlan_handle_frame(struct sk_buff **pskb)
 		skb = ip_check_defrag(skb, IP_DEFRAG_MACVLAN);
 		if (!skb)
 			return RX_HANDLER_CONSUMED;
+		eth = eth_hdr(skb);
 		src = macvlan_hash_lookup(port, eth->h_source);
 		if (!src)
 			/* frame comes from an external address */