lwtunnel: fix memory leak

The built lwtunnel_state struct has to be freed after comparison.

Fixes: 571e722 ("ipv4: support for fib route lwtunnel encap attributes")
Signed-off-by: Jiri Benc <jbenc@redhat.com>
Acked-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/lwtunnel.h

@@ -36,6 +36,11 @@ struct lwtunnel_encap_ops {
 };
 
 #ifdef CONFIG_LWTUNNEL
+static inline void lwtstate_free(struct lwtunnel_state *lws)
+{
+	kfree(lws);
+}
+
 static inline struct lwtunnel_state *
 lwtstate_get(struct lwtunnel_state *lws)
 {
@@ -51,7 +56,7 @@ static inline void lwtstate_put(struct lwtunnel_state *lws)
 		return;
 
 	if (atomic_dec_and_test(&lws->refcnt))
-		kfree(lws);
+		lwtstate_free(lws);
 }
 
 static inline bool lwtunnel_output_redirect(struct lwtunnel_state *lwtstate)

net/ipv4/fib_semantics.c

@@ -539,7 +539,7 @@ int fib_encap_match(struct net *net, u16 encap_type,
 {
 	struct lwtunnel_state *lwtstate;
 	struct net_device *dev = NULL;
-	int ret;
+	int ret, result = 0;
 
 	if (encap_type == LWTUNNEL_ENCAP_NONE)
 		return 0;
@@ -548,10 +548,12 @@ int fib_encap_match(struct net *net, u16 encap_type,
 		dev = __dev_get_by_index(net, oif);
 	ret = lwtunnel_build_state(dev, encap_type,
 				   encap, &lwtstate);
-	if (!ret)
-		return lwtunnel_cmp_encap(lwtstate, nh->nh_lwtstate);
+	if (!ret) {
+		result = lwtunnel_cmp_encap(lwtstate, nh->nh_lwtstate);
+		lwtstate_free(lwtstate);
+	}
 
-	return 0;
+	return result;
 }
 
 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi)