From: Nikolay Aleksandrov nikolay@nvidia.com
commit 000b7287b67555fee39d39fff75229dedde0dcbf upstream.
When an MRD advertisement is received on a bridge port with multicast snooping enabled, we mark it as a router port automatically, that includes adding that port to the router port list. The multicast lock protects that list, but it is not acquired in the MRD advertisement case leading to a race condition, we need to take it to fix the race.
Cc: stable@vger.kernel.org Cc: linus.luessing@c0d3.blue Fixes: 4b3087c7e37f ("bridge: Snoop Multicast Router Advertisements") Signed-off-by: Nikolay Aleksandrov nikolay@nvidia.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/bridge/br_multicast.c | 4 ++++ 1 file changed, 4 insertions(+)
--- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -3100,7 +3100,9 @@ static int br_ip4_multicast_mrd_rcv(stru igmp_hdr(skb)->type != IGMP_MRDISC_ADV) return -ENOMSG;
+ spin_lock(&br->multicast_lock); br_multicast_mark_router(br, port); + spin_unlock(&br->multicast_lock);
return 0; } @@ -3168,7 +3170,9 @@ static void br_ip6_multicast_mrd_rcv(str if (icmp6_hdr(skb)->icmp6_type != ICMPV6_MRDISC_ADV) return;
+ spin_lock(&br->multicast_lock); br_multicast_mark_router(br, port); + spin_unlock(&br->multicast_lock); }
static int br_multicast_ipv6_rcv(struct net_bridge *br,