[PATCH 4.4 025/342] net: Copy inner L3 and L4 headers as unaligned on GRE TEB

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Alexander Duyck <aduyck@xxxxxxxxxxxx>

[ 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 <aduyck@xxxxxxxxxxxx>
Acked-by: Tom Herbert <tom@xxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/core/flow_dissector.c |    7 +++++++
 1 file changed, 7 insertions(+)

--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -396,6 +396,13 @@ ip_proto_again:
 				goto out_bad;
 			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;
 		}
 
 		key_control->flags |= FLOW_DIS_ENCAPSULATION;