ipv4: Don't pass IP fragments to upper layer GRO handlers.

Upper layer GRO handlers can not handle IP fragments, so exit GRO processing in this case.

This fixes ESP GRO because the packet must be reassembled before we can decapsulate, otherwise we get authentication failures.

It also aligns IPv4 to IPv6 where packets with fragmentation headers are not passed to upper layer GRO handlers.

---
 net/ipv4/af_inet.c | 3 +++
 1 file changed, 3 insertions(+)

index 6b1fc6e..13a9a32 100644
@@ -1343,6 +1343,9 @@ struct sk_buff **inet_gro_receive(struct sk_buff **head, struct sk_buff *skb)
 	if (*(u8 *)iph != 0x45)
 		goto out_unlock;
 
+	if (ip_is_fragment(iph))
+		goto out_unlock;
+
 	if (unlikely(ip_fast_csum((u8 *)iph, 5)))
 		goto out_unlock;
 

2.7.4

From: Steffen Klassert <[email protected]>
Date: Fri, 28 Apr 2017 10:54:32 +0200

Applied, thank you.