Subject: [PATCH 20/34] net: Copy inner L3 and L4 headers as unaligned on GRE TEB

From: Alexander Duyck <[email-masked]>
Date: Tue, 9 Feb 2016 06:14:43 -0800

[ Upstream commit 78565208d73ca9b654fb9a6b142214d52eeedfd1 ]

This patch corrects the unaligned accesses seen on GRE TEB tunnels when
generating hash keys.  Specifically what this patch does is make it so that
we force the use of skb_copy_bits when the GRE inner headers will be
unaligned due to NET_IP_ALIGNED being a non-zero value.

Signed-off-by: Alexander Duyck <[email-masked]>
Acked-by: Tom Herbert <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 net/core/flow_dissector.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index f96d2ca..3556791 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -233,6 +233,13 @@ ipv6:
 					return false;
 				proto = eth->h_proto;
 				nhoff += sizeof(*eth);
+
+				/* Cap headers that we access via pointers at the
+				 * end of the Ethernet header as our maximum alignment
+				 * at that point is only 2 bytes.
+				 */
+				if (NET_IP_ALIGN)
+					hlen = nhoff;
 			}
 			goto again;
 		}
-- 
2.4.1