Eric Dumazet 8c2bd38b95 icmp: change the order of rate limits
ICMP messages are ratelimited :

After the blamed commits, the two rate limiters are applied in this order:

1) host wide ratelimit (icmp_global_allow())

2) Per destination ratelimit (inetpeer based)

In order to avoid side-channels attacks, we need to apply
the per destination check first.

This patch makes the following change :

1) icmp_global_allow() checks if the host wide limit is reached.
   But credits are not yet consumed. This is deferred to 3)

2) The per destination limit is checked/updated.
   This might add a new node in inetpeer tree.

3) icmp_global_consume() consumes tokens if prior operations succeeded.

This means that host wide ratelimit is still effective
in keeping inetpeer tree small even under DDOS.

As a bonus, I removed icmp_global.lock as the fast path
can use a lock-free operation.

Fixes: c0303efeab ("net: reduce cycles spend on ICMP replies that gets rate limited")
Fixes: 4cdf507d54 ("icmp: add a global rate limitation")
Reported-by: Keyu Man <keyu.man@email.ucr.edu>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Cc: Jesper Dangaard Brouer <hawk@kernel.org>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20240829144641.3880376-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-08-30 11:14:06 -07:00
2024-08-30 11:11:00 -07:00
2024-08-30 11:14:06 -07:00
2024-08-23 10:21:02 +01:00
2024-08-09 13:18:46 +01:00
2022-09-28 09:02:20 +02:00
2024-08-25 19:07:11 +12:00
2024-03-18 03:36:32 -06:00

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