[PATCH 5.18 115/231] icmp: Fix a data-race around sysctl_icmp_ignore_bogus_error_responses.

Greg Kroah-Hartman
2022-07-19T13:00:49Z

From: Kuniyuki Iwashima <kuniyu@amazon.com>

[ Upstream commit b04f9b7e85c7d7aecbada620e8759a662af068d3 ]

While reading sysctl_icmp_ignore_bogus_error_responses, 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 | 2 +-
net/ipv4/sysctl_net_ipv4.c | 2 ++
2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 2c402b4671a1..1a061d10949f 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -930,7 +930,7 @@ static bool icmp_unreach(struct sk_buff *skb)
* get the other vendor to fix their kit.
*/

- if (!net->ipv4.sysctl_icmp_ignore_bogus_error_responses &&
+ if (!READ_ONCE(net->ipv4.sysctl_icmp_ignore_bogus_error_responses) &&
inet_addr_type_dev_table(net, skb->dev, iph->daddr) == RTN_BROADCAST) {
net_warn_ratelimited("%pI4 sent an invalid ICMP type %u, code %u error to a broadcast: %pI4 on %s\n",
&ip_hdr(skb)->saddr,
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 6613351094ce..4cf2a6f560d4 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -630,6 +630,8 @@ static struct ctl_table ipv4_net_table[] = {
.maxlen = sizeof(u8),
.mode = 0644,
.proc_handler = proc_dou8vec_minmax,
+ .extra1 = SYSCTL_ZERO,
+ .extra2 = SYSCTL_ONE
},
{
.procname = "icmp_errors_use_inbound_ifaddr",
--
2.35.1