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icmp: Fix data-races around sysctl.

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[ Upstream commit 48d7ee321e ]

While reading icmp sysctl variables, they can be changed concurrently.
So, we need to add READ_ONCE() to avoid data-races.

Fixes: 4cdf507d54 ("icmp: add a global rate limitation")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Kuniyuki Iwashima 2022-07-06 16:40:02 -07:00 • committed by Greg Kroah-Hartman
commit e088ceb73c
1 changed files with 3 additions and 2 deletions
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5
net/ipv4/icmp.c
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@ -261,11 +261,12 @@ bool icmp_global_allow(void)
spin_lock(&icmp_global.lock);
delta = min_t(u32, now - icmp_global.stamp, HZ);
if (delta >= HZ / 50) {
incr = sysctl_icmp_msgs_per_sec * delta / HZ ;
incr = READ_ONCE(sysctl_icmp_msgs_per_sec) * delta / HZ;
if (incr)
WRITE_ONCE(icmp_global.stamp, now);
}
credit = min_t(u32, icmp_global.credit + incr, sysctl_icmp_msgs_burst);
credit = min_t(u32, icmp_global.credit + incr,
READ_ONCE(sysctl_icmp_msgs_burst));
if (credit) {
/* We want to use a credit of one in average, but need to randomize
* it for security reasons.