linux-kernel - [PATCH 5.18 113/231] icmp: Fix data-races around sysctl_icmp_echo_enable

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Date:   Tue, 19 Jul 2022 13:53:18 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Kuniyuki Iwashima <kuniyu@...zon.com>,
        "David S. Miller" <davem@...emloft.net>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.18 113/231] icmp: Fix data-races around sysctl_icmp_echo_enable_probe.

From: Kuniyuki Iwashima <kuniyu@...zon.com>

[ Upstream commit 4a2f7083cc6cb72dade9a63699ca352fad26d1cd ]

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

Fixes: d329ea5bd884 ("icmp: add response to RFC 8335 PROBE messages")
Fixes: 1fd07f33c3ea ("ipv6: ICMPV6: add response to ICMPV6 RFC 8335 PROBE messages")
Signed-off-by: Kuniyuki Iwashima <kuniyu@...zon.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 net/ipv4/icmp.c | 2 +-
 net/ipv6/icmp.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 92eaa96a9ff1..7edc8a3b1646 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -1025,7 +1025,7 @@ bool icmp_build_probe(struct sk_buff *skb, struct icmphdr *icmphdr)
 	u16 ident_len;
 	u8 status;
 
-	if (!net->ipv4.sysctl_icmp_echo_enable_probe)
+	if (!READ_ONCE(net->ipv4.sysctl_icmp_echo_enable_probe))
 		return false;
 
 	/* We currently only support probing interfaces on the proxy node
diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index e6b978ea0e87..26554aa6fc1b 100644
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -919,7 +919,7 @@ static int icmpv6_rcv(struct sk_buff *skb)
 		break;
 	case ICMPV6_EXT_ECHO_REQUEST:
 		if (!net->ipv6.sysctl.icmpv6_echo_ignore_all &&
-		    net->ipv4.sysctl_icmp_echo_enable_probe)
+		    READ_ONCE(net->ipv4.sysctl_icmp_echo_enable_probe))
 			icmpv6_echo_reply(skb);
 		break;
 
-- 
2.35.1