[RFC PATCH net-next 4/7] net: ipv6: mld: implement RFC3810 MLDv2 mode only
From: Daniel Borkmann <hidden>
Date: 2013-08-30 16:58:37
Subsystem:
networking [general], networking [ipv4/ipv6], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Ahern, Ido Schimmel, Linus Torvalds
RFC3810, 10. Security Considerations says under subsection 10.1. Query Message: A forged Version 1 Query message will put MLDv2 listeners on that link in MLDv1 Host Compatibility Mode. This scenario can be avoided by providing MLDv2 hosts with a configuration option to ignore Version 1 messages completely. Hence, implement a MLDv2-only mode that will ignore MLDv1 traffic: echo 2 > /proc/sys/net/ipv6/conf/ethX/force_mld_version Signed-off-by: Daniel Borkmann <redacted> Cc: Hannes Frederic Sowa <redacted> --- net/ipv6/mcast.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-)
diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index b6d3652..d6f2809 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c@@ -1112,9 +1112,21 @@ static bool mld_marksources(struct ifmcaddr6 *pmc, int nsrcs, return true; } +static bool mld_in_v2_mode_only(const struct inet6_dev *idev) +{ + return dev_net(idev->dev)->ipv6.devconf_all->force_mld_version == 2; +} + +static bool mld_in_v1_mode_only(const struct inet6_dev *idev) +{ + return dev_net(idev->dev)->ipv6.devconf_all->force_mld_version == 1; +} + static bool mld_in_v1_mode(const struct inet6_dev *idev) { - if (dev_net(idev->dev)->ipv6.devconf_all->force_mld_version == 1) + if (mld_in_v2_mode_only(idev)) + return false; + if (mld_in_v1_mode_only(idev)) return true; if (idev->cnf.force_mld_version == 1) return true;
@@ -1223,7 +1235,6 @@ int igmp6_event_query(struct sk_buff *skb) return -EINVAL; idev = __in6_dev_get(skb->dev); - if (idev == NULL) return 0;
@@ -1236,6 +1247,10 @@ int igmp6_event_query(struct sk_buff *skb) return -EINVAL; if (len == MLD_V1_QUERY_LEN) { + /* Ignore v1 queries */ + if (mld_in_v2_mode_only(idev)) + return 0; + /* MLDv1 router present */ max_delay = msecs_to_jiffies(ntohs(mld->mld_maxdelay));
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1.7.11.7