diff options
| author | Nikolay Aleksandrov <nikolay@nvidia.com> | 2021-12-27 20:21:16 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2021-12-29 23:59:38 +0300 |
| commit | f83a112bd91a494cdee671aec74e777470fb4a07 (patch) | |
| tree | d28b66672917adc72af376b2e1a64b1c1f0e8fa8 /net/bridge/br_multicast.c | |
| parent | 99b40610956a8a8755653a67392e2a8b772453be (diff) | |
| download | linux-f83a112bd91a494cdee671aec74e777470fb4a07.tar.xz | |
net: bridge: mcast: add and enforce startup query interval minimum
As reported[1] if startup query interval is set too low in combination with
large number of startup queries 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 admin know
that the startup interval has been set to the minimum. It doesn't make
sense to make the startup interval lower than the normal query interval
so use the same value of 1 second. 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 <eric.dumazet@gmail.com>
Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/bridge/br_multicast.c')
| -rw-r--r-- | net/bridge/br_multicast.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c index 998da4a2d209..de2409889489 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -4538,6 +4538,22 @@ void br_multicast_set_query_intvl(struct net_bridge_mcast *brmctx, brmctx->multicast_query_interval = intvl_jiffies; } +void br_multicast_set_startup_query_intvl(struct net_bridge_mcast *brmctx, + unsigned long val) +{ + unsigned long intvl_jiffies = clock_t_to_jiffies(val); + + if (intvl_jiffies < BR_MULTICAST_STARTUP_QUERY_INTVL_MIN) { + br_info(brmctx->br, + "trying to set multicast startup query interval below minimum, setting to %lu (%ums)\n", + jiffies_to_clock_t(BR_MULTICAST_STARTUP_QUERY_INTVL_MIN), + jiffies_to_msecs(BR_MULTICAST_STARTUP_QUERY_INTVL_MIN)); + intvl_jiffies = BR_MULTICAST_STARTUP_QUERY_INTVL_MIN; + } + + brmctx->multicast_startup_query_interval = intvl_jiffies; +} + /** * br_multicast_list_adjacent - Returns snooped multicast addresses * @dev: The bridge port adjacent to which to retrieve addresses |