From 99b40610956a8a8755653a67392e2a8b772453be Mon Sep 17 00:00:00 2001
From: Nikolay Aleksandrov <nikolay@nvidia.com>
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 <eric.dumazet@gmail.com>
Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
net/bridge/br_private.h | 3 +++
1 file changed, 3 insertions(+)
(limited to 'net/bridge/br_private.h')
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index c0efd697865a..4ed7f11042e8 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -28,6 +28,7 @@
#define BR_MAX_PORTS (1<<BR_PORT_BITS)
#define BR_MULTICAST_DEFAULT_HASH_MAX 4096
+#define BR_MULTICAST_QUERY_INTVL_MIN msecs_to_jiffies(1000)
#define BR_HWDOM_MAX BITS_PER_LONG
@@ -963,6 +964,8 @@ int br_multicast_dump_querier_state(struct sk_buff *skb,
int nest_attr);
size_t br_multicast_querier_state_size(void);
size_t br_rports_size(const struct net_bridge_mcast *brmctx);
+void br_multicast_set_query_intvl(struct net_bridge_mcast *brmctx,
+ unsigned long val);
static inline bool br_group_is_l2(const struct br_ip *group)
{
--
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