From 99b40610956a8a8755653a67392e2a8b772453be Mon Sep 17 00:00:00 2001 From: Nikolay Aleksandrov Date: Mon, 27 Dec 2021 19:21:15 +0200 Subject: net: bridge: mcast: add and enforce query interval minimum As reported[1] if query interval is set too low and we have multiple bridges or even a single bridge with multiple querier vlans configured we can crash the machine. Add a 1 second minimum which must be enforced by overwriting the value if set lower (i.e. without returning an error) to avoid breaking user-space. If that happens a log message is emitted to let the administrator know that the interval has been set to the minimum. The issue has been present since these intervals could be user-controlled. [1] https://lore.kernel.org/netdev/e8b9ce41-57b9-b6e2-a46a-ff9c791cf0ba@gmail.com/ Fixes: d902eee43f19 ("bridge: Add multicast count/interval sysfs entries") Reported-by: Eric Dumazet Signed-off-by: Nikolay Aleksandrov Signed-off-by: Jakub Kicinski --- net/bridge/br_multicast.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'net/bridge/br_multicast.c') diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c index f3d751105343..998da4a2d209 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -4522,6 +4522,22 @@ int br_multicast_set_mld_version(struct net_bridge_mcast *brmctx, } #endif +void br_multicast_set_query_intvl(struct net_bridge_mcast *brmctx, + unsigned long val) +{ + unsigned long intvl_jiffies = clock_t_to_jiffies(val); + + if (intvl_jiffies < BR_MULTICAST_QUERY_INTVL_MIN) { + br_info(brmctx->br, + "trying to set multicast query interval below minimum, setting to %lu (%ums)\n", + jiffies_to_clock_t(BR_MULTICAST_QUERY_INTVL_MIN), + jiffies_to_msecs(BR_MULTICAST_QUERY_INTVL_MIN)); + intvl_jiffies = BR_MULTICAST_QUERY_INTVL_MIN; + } + + brmctx->multicast_query_interval = intvl_jiffies; +} + /** * br_multicast_list_adjacent - Returns snooped multicast addresses * @dev: The bridge port adjacent to which to retrieve addresses -- cgit v1.2.1