[PATCH 5.4 34/71] icmp: Fix a data-race around sysctl_icmp_ratelimit.

Greg Kroah-Hartman
2022-07-19T12:11:34Z

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 a590ff81e5f8..e05e972445fe 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -328,7 +328,8 @@ 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