[3.16.y-ckt stable] Patch "ip6_gre: fix endianness errors in ip6gre_err" has been added to staging queue

Luis Henriques luis.henriques at canonical.com
Tue Mar 24 15:33:55 UTC 2015

This is a note to let you know that I have just added a patch titled

    ip6_gre: fix endianness errors in ip6gre_err

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:


This patch is scheduled to be released in version 3.16.7-ckt9.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see



>From 468763f783f36d044a9ee74849fca9e8b8cb332a Mon Sep 17 00:00:00 2001
From: Sabrina Dubroca <sd at queasysnail.net>
Date: Wed, 4 Feb 2015 15:25:09 +0100
Subject: ip6_gre: fix endianness errors in ip6gre_err

commit d1e158e2d7a0a91110b206653f0e02376e809150 upstream.

info is in network byte order, change it back to host byte order
before use. In particular, the current code sets the MTU of the tunnel
to a wrong (too big) value.

Fixes: c12b395a4664 ("gre: Support GRE over IPv6")
Signed-off-by: Sabrina Dubroca <sd at queasysnail.net>
Acked-by: Eric Dumazet <edumazet at google.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
 net/ipv6/ip6_gre.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 0baac7127c57..07506e7a8917 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -414,7 +414,7 @@ static void ip6gre_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 		if (code == ICMPV6_HDR_FIELD)
 			teli = ip6_tnl_parse_tlv_enc_lim(skb, skb->data);

-		if (teli && teli == info - 2) {
+		if (teli && teli == be32_to_cpu(info) - 2) {
 			tel = (struct ipv6_tlv_tnl_enc_lim *) &skb->data[teli];
 			if (tel->encap_limit == 0) {
 				net_warn_ratelimited("%s: Too small encapsulation limit or routing loop in tunnel!\n",
@@ -426,7 +426,7 @@ static void ip6gre_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
-		mtu = info - offset;
+		mtu = be32_to_cpu(info) - offset;
 		if (mtu < IPV6_MIN_MTU)
 			mtu = IPV6_MIN_MTU;
 		t->dev->mtu = mtu;

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