From 549984a679bde3d755bce5a46ec69bea9c6260fd Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Wed, 6 Jul 2022 16:40:02 -0700 Subject: [PATCH] icmp: Fix data-races around sysctl. [ Upstream commit ae90c421c5d3286b9a4eee867deb3beac67e1e4c ] While reading icmp sysctl variables, they can be changed concurrently. So, we need to add READ_ONCE() to avoid data-races. Fixes: 0fcdcc7c3da1 ("icmp: add a global rate limitation") Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/ipv4/icmp.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) 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. -- 2.39.5