[PATCH 3.14 109/140] ip_tunnel: Set network header properly for IP_ECN_decapsulate()

Greg Kroah-Hartman
2014-05-29T05:08:58Z

From: Ying Cai <ycai@google.com>

[ Upstream commit e96f2e7c430014eff52c93cabef1ad4f42ed0db1 ]

In ip_tunnel_rcv(), set skb->network_header to inner IP header
before IP_ECN_decapsulate().

Without the fix, IP_ECN_decapsulate() takes outer IP header as
inner IP header, possibly causing error messages or packet drops.

Note that this skb_reset_network_header() call was in this spot when
the original feature for checking consistency of ECN bits through
tunnels was added in eccc1bb8d4b4 ("tunnel: drop packet if ECN present
with not-ECT"). It was only removed from this spot in 3d7b46cd20e3
("ip_tunnel: push generic protocol handling to ip_tunnel module.").

Fixes: 3d7b46cd20e3 ("ip_tunnel: push generic protocol handling to ip_tunnel module.")
Reported-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Ying Cai <ycai@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/ipv4/ip_tunnel.c | 2 ++
1 file changed, 2 insertions(+)

--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -438,6 +438,8 @@ int ip_tunnel_rcv(struct ip_tunnel *tunn
tunnel->i_seqno = ntohl(tpi->seq) + 1;
}

+ skb_reset_network_header(skb);
+
err = IP_ECN_decapsulate(iph, skb);
if (unlikely(err)) {
if (log_ecn_error)