netfilter: nft_limit: fix stateful object memory leak

We need to provide a destroy callback to release the extra fields.

Fixes: 3b9e2ea6 ("netfilter: nft_limit: move stateful fields out of expression data")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nft_limit.c

@@ -340,11 +340,20 @@ static int nft_limit_obj_pkts_dump(struct sk_buff *skb,
 	return nft_limit_dump(skb, &priv->limit, NFT_LIMIT_PKTS);
 }
 
+static void nft_limit_obj_pkts_destroy(const struct nft_ctx *ctx,
+				       struct nft_object *obj)
+{
+	struct nft_limit_priv_pkts *priv = nft_obj_data(obj);
+
+	nft_limit_destroy(ctx, &priv->limit);
+}
+
 static struct nft_object_type nft_limit_obj_type;
 static const struct nft_object_ops nft_limit_obj_pkts_ops = {
 	.type		= &nft_limit_obj_type,
 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_limit_priv_pkts)),
 	.init		= nft_limit_obj_pkts_init,
+	.destroy	= nft_limit_obj_pkts_destroy,
 	.eval		= nft_limit_obj_pkts_eval,
 	.dump		= nft_limit_obj_pkts_dump,
 };
@@ -378,11 +387,20 @@ static int nft_limit_obj_bytes_dump(struct sk_buff *skb,
 	return nft_limit_dump(skb, priv, NFT_LIMIT_PKT_BYTES);
 }
 
+static void nft_limit_obj_bytes_destroy(const struct nft_ctx *ctx,
+					struct nft_object *obj)
+{
+	struct nft_limit_priv *priv = nft_obj_data(obj);
+
+	nft_limit_destroy(ctx, priv);
+}
+
 static struct nft_object_type nft_limit_obj_type;
 static const struct nft_object_ops nft_limit_obj_bytes_ops = {
 	.type		= &nft_limit_obj_type,
 	.size		= sizeof(struct nft_limit_priv),
 	.init		= nft_limit_obj_bytes_init,
+	.destroy	= nft_limit_obj_bytes_destroy,
 	.eval		= nft_limit_obj_bytes_eval,
 	.dump		= nft_limit_obj_bytes_dump,
 };