[PATCH 3.11 166/208] net: clear local_df when passing skb between namespaces

[Luis Henriques]

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

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

From: Hannes Frederic Sowa <hannes at stressinduktion.org>

commit 239c78db9c41a8f524cce60507440d72229d73bc upstream.

We must clear local_df when passing the skb between namespaces as the
packet is not local to the new namespace any more and thus may not get
fragmented by local rules. Fred Templin noticed that other namespaces
do fragment IPv6 packets while forwarding. Instead they should have send
back a PTB.

The same problem should be present when forwarding DF-IPv4 packets
between namespaces.

Reported-by: Templin, Fred L <Fred.L.Templin at boeing.com>
Signed-off-by: Hannes Frederic Sowa <hannes at stressinduktion.org>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 net/core/skbuff.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index a75022e..b2cd9a4 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3511,6 +3511,7 @@ void skb_scrub_packet(struct sk_buff *skb)
 	skb->tstamp.tv64 = 0;
 	skb->pkt_type = PACKET_HOST;
 	skb->skb_iif = 0;
+	skb->local_df = 0;
 	skb_dst_drop(skb);
 	skb->mark = 0;
 	secpath_reset(skb);
-- 
1.8.3.2