path: root/net/bridge
diff options
authorLinus Lüssing <linus.luessing@web.de>2014-03-04 03:57:35 +0100
committerDavid S. Miller <davem@davemloft.net>2014-03-05 20:40:24 -0500
commit6565b9eeef194afbb3beec80d6dd2447f4091f8c (patch)
treeb2ac707f8f107ab4ad7f3614b3226e7cb50b8a74 /net/bridge
parent24b9bf43e93e0edd89072da51cf1fab95fc69dec (diff)
bridge: multicast: add sanity check for query source addresses
MLD queries are supposed to have an IPv6 link-local source address according to RFC2710, section 4 and RFC3810, section 5.1.14. This patch adds a sanity check to ignore such broken MLD queries. Without this check, such malformed MLD queries can result in a denial of service: The queries are ignored by any MLD listener therefore they will not respond with an MLD report. However, without this patch these malformed MLD queries would enable the snooping part in the bridge code, potentially shutting down the according ports towards these hosts for multicast traffic as the bridge did not learn about these listeners. Reported-by: Jan Stancek <jstancek@redhat.com> Signed-off-by: Linus Lüssing <linus.luessing@web.de> Reviewed-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/bridge')
1 files changed, 6 insertions, 0 deletions
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index ef66365b7354..fb0e36fac668 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -1235,6 +1235,12 @@ static int br_ip6_multicast_query(struct net_bridge *br,
(port && port->state == BR_STATE_DISABLED))
goto out;
+ /* RFC2710+RFC3810 (MLDv1+MLDv2) require link-local source addresses */
+ if (!(ipv6_addr_type(&ip6h->saddr) & IPV6_ADDR_LINKLOCAL)) {
+ err = -EINVAL;
+ goto out;
+ }
if (skb->len == sizeof(*mld)) {
if (!pskb_may_pull(skb, sizeof(*mld))) {
err = -EINVAL;