From 9b83e0319840eca758ef586776a427284ff767bf Mon Sep 17 00:00:00 2001
From: Steffen Klassert <steffen.klassert@secunet.com>
Date: Fri, 28 Apr 2017 10:54:32 +0200
Subject: [PATCH] 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.

Fixes: 7785bba299a8 ("esp: Add a software GRO codepath")
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 net/ipv4/af_inet.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 6b1fc6e4278ef..13a9a3297eae3 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -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;
 
-- 
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