netfilter: nf_tables: support different set binding types

Currently a set binding is assumed to be related to a lookup and, in
case of maps, a data load.

In order to use bindings for set updates, the loop detection checks
must be restricted to map operations only. Add a flags member to the
binding struct to hold the set "action" flags such as NFT_SET_MAP,
and perform loop detection based on these.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

include/net/netfilter/nf_tables.h

@@ -316,6 +316,7 @@ static inline unsigned long nft_set_gc_interval(const struct nft_set *set)
  *
  *	@list: set bindings list node
  *	@chain: chain containing the rule bound to the set
+ *	@flags: set action flags
  *
  *	A set binding contains all information necessary for validation
  *	of new elements added to a bound set.
@@ -323,6 +324,7 @@ static inline unsigned long nft_set_gc_interval(const struct nft_set *set)
 struct nft_set_binding {
 	struct list_head		list;
 	const struct nft_chain		*chain;
+	u32				flags;
 };
 
 int nf_tables_bind_set(const struct nft_ctx *ctx, struct nft_set *set,

net/netfilter/nf_tables_api.c

@@ -2811,12 +2811,13 @@ int nf_tables_bind_set(const struct nft_ctx *ctx, struct nft_set *set,
 	if (!list_empty(&set->bindings) && set->flags & NFT_SET_ANONYMOUS)
 		return -EBUSY;
 
-	if (set->flags & NFT_SET_MAP) {
+	if (binding->flags & NFT_SET_MAP) {
 		/* If the set is already bound to the same chain all
 		 * jumps are already validated for that chain.
 		 */
 		list_for_each_entry(i, &set->bindings, list) {
-			if (i->chain == binding->chain)
+			if (binding->flags & NFT_SET_MAP &&
+			    i->chain == binding->chain)
 				goto bind;
 		}
 
@@ -3312,6 +3313,9 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set,
 				.chain	= (struct nft_chain *)binding->chain,
 			};
 
+			if (!(binding->flags & NFT_SET_MAP))
+				continue;
+
 			err = nft_validate_data_load(&bind_ctx, dreg,
 						     &data, d2.type);
 			if (err < 0)
@@ -4063,7 +4067,8 @@ static int nf_tables_check_loops(const struct nft_ctx *ctx,
 			continue;
 
 		list_for_each_entry(binding, &set->bindings, list) {
-			if (binding->chain != chain)
+			if (!(binding->flags & NFT_SET_MAP) ||
+			    binding->chain != chain)
 				continue;
 
 			iter.skip 	= 0;

net/netfilter/nft_lookup.c

@@ -92,6 +92,8 @@ static int nft_lookup_init(const struct nft_ctx *ctx,
 	} else if (set->flags & NFT_SET_MAP)
 		return -EINVAL;
 
+	priv->binding.flags = set->flags & NFT_SET_MAP;
+
 	err = nf_tables_bind_set(ctx, set, &priv->binding);
 	if (err < 0)
 		return err;