net/sched: cls_flower: Reject duplicated rules also under skip_sw

Currently, duplicated rules are rejected only for skip_hw or "none",
hence allowing users to push duplicates into HW for no reason.

Use the flower tables to protect for that.
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NPaul Blakey <paulb@mellanox.com>
Reported-by: NChris Mi <chrism@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/sched/cls_flower.c

@@ -1238,18 +1238,16 @@ static int fl_change(struct net *net, struct sk_buff *in_skb,
 	if (err)
 		goto errout_idr;
 
-	if (!tc_skip_sw(fnew->flags)) {
-		if (!fold && fl_lookup(fnew->mask, &fnew->mkey)) {
-			err = -EEXIST;
-			goto errout_mask;
-		}
-
-		err = rhashtable_insert_fast(&fnew->mask->ht, &fnew->ht_node,
-					     fnew->mask->filter_ht_params);
-		if (err)
-			goto errout_mask;
+	if (!fold && fl_lookup(fnew->mask, &fnew->mkey)) {
+		err = -EEXIST;
+		goto errout_mask;
 	}
 
+	err = rhashtable_insert_fast(&fnew->mask->ht, &fnew->ht_node,
+				     fnew->mask->filter_ht_params);
+	if (err)
+		goto errout_mask;
+
 	if (!tc_skip_hw(fnew->flags)) {
 		err = fl_hw_replace_filter(tp, fnew, extack);
 		if (err)
@@ -1303,9 +1301,8 @@ static int fl_delete(struct tcf_proto *tp, void *arg, bool *last,
 	struct cls_fl_head *head = rtnl_dereference(tp->root);
 	struct cls_fl_filter *f = arg;
 
-	if (!tc_skip_sw(f->flags))
-		rhashtable_remove_fast(&f->mask->ht, &f->ht_node,
-				       f->mask->filter_ht_params);
+	rhashtable_remove_fast(&f->mask->ht, &f->ht_node,
+			       f->mask->filter_ht_params);
 	__fl_delete(tp, f, extack);
 	*last = list_empty(&head->masks);
 	return 0;