[PATCH 4.19 19/48] icmp: Fix a data-race around sysctl_icmp_ratelimit.

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Kuniyuki Iwashima <kuniyu@amazon.com>

[ Upstream commit 2a4eb714841f288cf51c7d942d98af6a8c6e4b01 ]

While reading sysctl_icmp_ratelimit, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its reader.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
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>
---
 net/ipv4/icmp.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 953cc70851cf..eb29da8971e1 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -333,7 +333,8 @@ static bool icmpv4_xrlim_allow(struct net *net, struct rtable *rt,
 
 	vif = l3mdev_master_ifindex(dst->dev);
 	peer = inet_getpeer_v4(net->ipv4.peers, fl4->daddr, vif, 1);
-	rc = inet_peer_xrlim_allow(peer, net->ipv4.sysctl_icmp_ratelimit);
+	rc = inet_peer_xrlim_allow(peer,
+				   READ_ONCE(net->ipv4.sysctl_icmp_ratelimit));
 	if (peer)
 		inet_putpeer(peer);
 out:
-- 
2.35.1