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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Kuniyuki Iwashima <kuniyu@amazon.com>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 059/112] icmp: Fix a data-race around sysctl_icmp_ratelimit.
Date:   Tue, 19 Jul 2022 13:53:52 +0200
Message-Id: <20220719114632.234741805@linuxfoundation.org>
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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 f22c0d55f479..9483c2a16b78 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