[NETFILTER]: nf_nat: properly use RCU for ip_nat_decode_session

We need to use rcu_assign_pointer/rcu_dereference to avoid races.
Also remove an obsolete CONFIG_IP_NAT_NEEDED ifdef.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 3 deletions

diff --git a/include/linux/netfilter.h b/include/linux/netfilter.h
index 0947424d01d6..1a8487325a4f 100644
--- a/include/linux/netfilter.h
+++ b/include/linux/netfilter.h
@@ -256,11 +256,16 @@ extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *);
 static inline void
 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family)
 {
-#if defined(CONFIG_IP_NF_NAT_NEEDED) || defined(CONFIG_NF_NAT_NEEDED)
+#ifdef CONFIG_NF_NAT_NEEDED
         void (*decodefn)(struct sk_buff *, struct flowi *);
 
-        if (family == AF_INET && (decodefn = ip_nat_decode_session) != NULL)
-                decodefn(skb, fl);
+        if (family == AF_INET) {
+                rcu_read_lock();
+                decodefn = rcu_dereference(ip_nat_decode_session);
+                if (decodefn)
+                        decodefn(skb, fl);
+                rcu_read_unlock();
+        }
 #endif
 }