netfilter: nf_flow_table: fix missing error check for rhashtable_insert_fast

rhashtable_insert_fast() may return an error value when memory
allocation fails, but flow_offload_add() does not check for errors.
This patch just adds missing error checking.

Fixes: ac2a6666 ("netfilter: add generic flow table infrastructure")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nf_flow_table_core.c

@@ -185,14 +185,25 @@ static const struct rhashtable_params nf_flow_offload_rhash_params = {
 
 int flow_offload_add(struct nf_flowtable *flow_table, struct flow_offload *flow)
 {
-	flow->timeout = (u32)jiffies;
+	int err;
 
-	rhashtable_insert_fast(&flow_table->rhashtable,
-			       &flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].node,
+	err = rhashtable_insert_fast(&flow_table->rhashtable,
+				     &flow->tuplehash[0].node,
 				     nf_flow_offload_rhash_params);
-	rhashtable_insert_fast(&flow_table->rhashtable,
-			       &flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].node,
+	if (err < 0)
+		return err;
+
+	err = rhashtable_insert_fast(&flow_table->rhashtable,
+				     &flow->tuplehash[1].node,
 				     nf_flow_offload_rhash_params);
+	if (err < 0) {
+		rhashtable_remove_fast(&flow_table->rhashtable,
+				       &flow->tuplehash[0].node,
+				       nf_flow_offload_rhash_params);
+		return err;
+	}
+
+	flow->timeout = (u32)jiffies;
 	return 0;
 }
 EXPORT_SYMBOL_GPL(flow_offload_add);