[PATCH v1 net 08/15] icmp: Fix a data-race around sysctl_icmp_errors_use_inbound_ifaddr.

[Kuniyuki Iwashima]

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@xxxxxxxxxx>
---
CC: J. Simonetti <jeroen@xxxxxxxxxxxx>
---
 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 0c01696c5584..a49b68d6b969 100644
--- 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 3122e652f3c3..66159d49a575 100644
--- 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",
-- 
2.30.2