icmp: Fix a data-race around sysctl_icmp_ignore_bogus_error_responses.

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>

diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 4b1d84d..0c01696 100644 (file)
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -933,7 +933,7 @@ static enum skb_drop_reason 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 cb53476..3122e65 100644 (file)
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -626,6 +626,8 @@ 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",