This is a note to let you know that I've just added the patch titled
net: bridge: multicast: fix MRD advertisement router port marking race
to the 5.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-bridge-multicast-fix-mrd-advertisement-router-port-marking-race.patch
and it can be found in the queue-5.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 000b7287b67555fee39d39fff75229dedde0dcbf Mon Sep 17 00:00:00 2001
From: Nikolay Aleksandrov <nikolay@xxxxxxxxxx>
Date: Sun, 11 Jul 2021 12:56:29 +0300
Subject: net: bridge: multicast: fix MRD advertisement router port marking race
From: Nikolay Aleksandrov <nikolay@xxxxxxxxxx>
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@xxxxxxxxxxxxxxx
Cc: linus.luessing@xxxxxxxxx
Fixes: 4b3087c7e37f ("bridge: Snoop Multicast Router Advertisements")
Signed-off-by: Nikolay Aleksandrov <nikolay@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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,
Patches currently in stable-queue which might be from nikolay@xxxxxxxxxx are
queue-5.12/net-bridge-multicast-fix-mrd-advertisement-router-port-marking-race.patch
queue-5.12/net-bridge-multicast-fix-pim-hello-router-port-marking-race.patch
