netfilter: nf_tables: permit update of set size

Now that set->nelems is always updated permit update of the sets max size.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

include/net/netfilter/nf_tables.h

@@ -1589,6 +1589,7 @@ struct nft_trans_set {
 	u64				timeout;
 	bool				update;
 	bool				bound;
+	u32				size;
 };
 
 #define nft_trans_set(trans)	\
@@ -1603,6 +1604,8 @@ struct nft_trans_set {
 	(((struct nft_trans_set *)trans->data)->timeout)
 #define nft_trans_set_gc_int(trans)	\
 	(((struct nft_trans_set *)trans->data)->gc_int)
+#define nft_trans_set_size(trans)	\
+	(((struct nft_trans_set *)trans->data)->size)
 
 struct nft_trans_chain {
 	bool				update;

net/netfilter/nf_tables_api.c

@@ -483,6 +483,7 @@ static int __nft_trans_set_add(const struct nft_ctx *ctx, int msg_type,
 		nft_trans_set_update(trans) = true;
 		nft_trans_set_gc_int(trans) = desc->gc_int;
 		nft_trans_set_timeout(trans) = desc->timeout;
+		nft_trans_set_size(trans) = desc->size;
 	}
 	nft_trans_commit_list_add_tail(ctx->net, trans);
 
@@ -9428,6 +9429,9 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb)
 
 				WRITE_ONCE(set->timeout, nft_trans_set_timeout(trans));
 				WRITE_ONCE(set->gc_int, nft_trans_set_gc_int(trans));
+
+				if (nft_trans_set_size(trans))
+					WRITE_ONCE(set->size, nft_trans_set_size(trans));
 			} else {
 				nft_clear(net, nft_trans_set(trans));
 				/* This avoids hitting -EBUSY when deleting the table