[PATCH 4.4 089/114] net: bridge: remove ipv6 zero address check in mcast queries

Greg Kroah-Hartman
2018-11-09T07:38:01Z

From: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>

commit 0fe5119e267f3e3d8ac206895f5922195ec55a8a upstream.

Recently a check was added which prevents marking of routers with zero
source address, but for IPv6 that cannot happen as the relevant RFCs
actually forbid such packets:
RFC 2710 (MLDv1):
"To be valid, the Query message MUST
come from a link-local IPv6 Source Address, be at least 24 octets
long, and have a correct MLD checksum."

Same goes for RFC 3810.

And also it can be seen as a requirement in ipv6_mc_check_mld_query()
which is used by the bridge to validate the message before processing
it. Thus any queries with :: source address won't be processed anyway.
So just remove the check for zero IPv6 source address from the query
processing function.

Fixes: 5a2de63fd1a5 ("bridge: do not add port to router list when receives query with source 0.0.0.0")
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
net/bridge/br_multicast.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -1267,8 +1267,7 @@ static void br_multicast_query_received(
* is 0.0.0.0 should not be added to router port list.
*/
if ((saddr->proto == htons(ETH_P_IP) && saddr->u.ip4) ||
- (saddr->proto == htons(ETH_P_IPV6) &&
- !ipv6_addr_any(&saddr->u.ip6)))
+ saddr->proto == htons(ETH_P_IPV6))
br_multicast_mark_router(br, port);
}