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authorHagen Paul Pfeifer <hagen@jauu.net>2015-01-15 22:34:25 +0100
committerDavid S. Miller <davem@davemloft.net>2015-01-19 14:52:07 -0500
commit9d289715eb5c252ae15bd547cb252ca547a3c4f2 (patch)
treeb1a1f354702809ff53e038ff44f9b88d7b0b0a08
parent2061dcd6bff8b774b4fac8b0739b6be3f87bc9f2 (diff)
downloadlinux-9d289715eb5c252ae15bd547cb252ca547a3c4f2.tar.gz
ipv6: stop sending PTB packets for MTU < 1280
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@si6networks.com> Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net> Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/ipv6/route.c7
1 files changed, 2 insertions, 5 deletions
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index c91083156ed..166e33bed22 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1160,12 +1160,9 @@ 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);
}