From: Kuniyuki Iwashima <kuniyu@amazon.com>
Date: Wed, 6 Jul 2022 23:40:02 +0000 (-0700)
Subject: icmp: Fix data-races around sysctl.
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=e2828e8c605853f71267825c9415437c0a93e4f2;p=linux.git

icmp: Fix data-races around sysctl.

[ Upstream commit 48d7ee321ea5182c6a70782aa186422a70e67e22 ]

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

Fixes: 4cdf507d5452 ("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>
---

diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index b7e277d8a84d2..b5766b62ca97a 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -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.