macsec: fix use-after-free of skb during RX

[ Upstream commit 095c02da80a41cf6d311c504d8955d6d1c2add10 ]

Fix use-after-free of skb when rx_handler returns RX_HANDLER_PASS.

Signed-off-by: Andreas Steinmetz <ast@domdv.de>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c
index 653f0b1..70ca128 100644
--- a/drivers/net/macsec.c
+++ b/drivers/net/macsec.c
@@ -1105,10 +1105,9 @@
 	}
 
 	skb = skb_unshare(skb, GFP_ATOMIC);
-	if (!skb) {
-		*pskb = NULL;
+	*pskb = skb;
+	if (!skb)
 		return RX_HANDLER_CONSUMED;
-	}
 
 	pulled_sci = pskb_may_pull(skb, macsec_extra_len(true));
 	if (!pulled_sci) {