icmp: Fix a data-race around sysctl_icmp_errors_use_inbound_ifaddr.

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

Fixes: d125149c725d ("[IPV4]: Sysctl configurable icmp error source address.")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 0c01696c5584a0707d7263a3f7ab54088456fc81..a49b68d6b969892d63f43dc8faaca2be32ad9137 100644 (file)
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -693,7 +693,7 @@ 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 3122e652f3c30e9447cff2593aa9d256fdff41b8..66159d49a575b74794798171cacc393fc9553c58 100644 (file)
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -635,6 +635,8 @@ 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",