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authorLinus Lüssing <linus.luessing@web.de>2014-03-04 03:57:35 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-04-26 17:13:16 -0700
commit098c9960de5f0c682f1cdddfe51648d4232a952d (patch)
treeb5a0438bbaf4ab381f5ba41ffb288e22b9ab9abf
parent978a9b75b98d918e757eac01d0008fd30252e3bf (diff)
bridge: multicast: add sanity check for query source addresses
[ Upstream commit 6565b9eeef194afbb3beec80d6dd2447f4091f8c ] 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/bridge/br_multicast.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index cef202a94112..0b870d75a542 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -1138,6 +1138,12 @@ static int br_ip6_multicast_query(struct net_bridge *br,
br_multicast_query_received(br, port, !ipv6_addr_any(&ip6h->saddr));
+ /* 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;