icmp: Fix a data-race around sysctl_icmp_errors_use_inbound_ifaddr.

[ Upstream commit d2efabce81db7eed1c98fa1a3f203f0edd738ac3 ]

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

Fixes: 1c2fb7f93cb2 ("[IPV4]: Sysctl configurable icmp error source address.")
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>

diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 6f444b2..e40a79b 100644 (file)
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -702,7 +702,7 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info,
 
                rcu_read_lock();
                if (rt_is_input_route(rt) &&
-                   net->ipv4.sysctl_icmp_errors_use_inbound_ifaddr)
+                   READ_ONCE(net->ipv4.sysctl_icmp_errors_use_inbound_ifaddr))
                        dev = dev_get_by_index_rcu(net, inet_iif(skb_in));
 
                if (dev)

diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 5186303..49a8167 100644 (file)
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -648,6 +648,8 @@ 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_ratelimit",