[PATCH 5.18 113/231] icmp: Fix data-races around sysctl_icmp_echo_enable_probe.

Greg Kroah-Hartman
2022-07-19T12:58:58Z

From: Kuniyuki Iwashima <kuniyu@amazon.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@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.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