[patch added to the 3.12 stable tree] ipv6: stop sending PTB packets for MTU < 1280

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



From: Hagen Paul Pfeifer <hagen@xxxxxxxx>

This patch has been added to the 3.12 stable tree. If you have any
objections, please let us know.

===============

[ Upstream commit 9d289715eb5c252ae15bd547cb252ca547a3c4f2 ]

Reduce the attack vector and stop generating IPv6 Fragment Header for
paths with an MTU smaller than the minimum required IPv6 MTU
size (1280 byte) - called atomic fragments.

See IETF I-D "Deprecating the Generation of IPv6 Atomic Fragments" [1]
for more information and how this "feature" can be misused.

[1] https://tools.ietf.org/html/draft-ietf-6man-deprecate-atomfrag-generation-00

Signed-off-by: Fernando Gont <fgont@xxxxxxxxxxxxxxx>
Signed-off-by: Hagen Paul Pfeifer <hagen@xxxxxxxx>
Acked-by: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
 net/ipv6/route.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index b4bb6a29aa16..1d0c5d66d637 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1144,12 +1144,9 @@ static void ip6_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
 		struct net *net = dev_net(dst->dev);
 
 		rt6->rt6i_flags |= RTF_MODIFIED;
-		if (mtu < IPV6_MIN_MTU) {
-			u32 features = dst_metric(dst, RTAX_FEATURES);
+		if (mtu < IPV6_MIN_MTU)
 			mtu = IPV6_MIN_MTU;
-			features |= RTAX_FEATURE_ALLFRAG;
-			dst_metric_set(dst, RTAX_FEATURES, features);
-		}
+
 		dst_metric_set(dst, RTAX_MTU, mtu);
 		rt6_update_expires(rt6, net->ipv6.sysctl.ip6_rt_mtu_expires);
 	}
-- 
2.2.2

--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [Linux Kernel]     [Kernel Development Newbies]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Hiking]     [Linux Kernel]     [Linux SCSI]