bridge: multicast: enable snooping on general queries only
Without this check someone could easily create a denial of service
by injecting multicast-specific queries to enable the bridge
snooping part if no real querier issuing periodic general queries
is present on the link which would result in the bridge wrongly
shutting down ports for multicast traffic as the bridge did not learn
about these listeners.
With this patch the snooping code is enabled upon receiving valid,
general queries only.
Signed-off-by: Linus Lüssing <linus.luessing@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index e56bae4..93067ec 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -1127,9 +1127,10 @@
struct net_bridge_port *port,
struct bridge_mcast_querier *querier,
int saddr,
+ bool is_general_query,
unsigned long max_delay)
{
- if (saddr)
+ if (saddr && is_general_query)
br_multicast_update_querier_timer(br, querier, max_delay);
else if (timer_pending(&querier->timer))
return;
@@ -1190,7 +1191,7 @@
}
br_multicast_query_received(br, port, &br->ip4_querier, !!iph->saddr,
- max_delay);
+ !group, max_delay);
if (!group)
goto out;
@@ -1282,7 +1283,8 @@
}
br_multicast_query_received(br, port, &br->ip6_querier,
- !ipv6_addr_any(&ip6h->saddr), max_delay);
+ !ipv6_addr_any(&ip6h->saddr),
+ is_general_query, max_delay);
if (!group)
goto out;