netfilter: nf_tables: disallow element updates of bound anonymous sets

[ Upstream commit c88c535b592d3baeee74009f3eceeeaf0fdd5e1b ]

Anonymous sets come with NFT_SET_CONSTANT from userspace. Although API
allows to create anonymous sets without NFT_SET_CONSTANT, it makes no
sense to allow to add and to delete elements for bound anonymous sets.

Fixes: 96518518cc41 ("netfilter: add nftables")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 241a303..e091c55 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -4220,7 +4220,8 @@
 			return PTR_ERR(set);
 	}
 
-	if (!list_empty(&set->bindings) && set->flags & NFT_SET_CONSTANT)
+	if (!list_empty(&set->bindings) &&
+	    (set->flags & (NFT_SET_CONSTANT | NFT_SET_ANONYMOUS)))
 		return -EBUSY;
 
 	nla_for_each_nested(attr, nla[NFTA_SET_ELEM_LIST_ELEMENTS], rem) {
@@ -4399,7 +4400,9 @@
 				   genmask);
 	if (IS_ERR(set))
 		return PTR_ERR(set);
-	if (!list_empty(&set->bindings) && set->flags & NFT_SET_CONSTANT)
+
+	if (!list_empty(&set->bindings) &&
+	    (set->flags & (NFT_SET_CONSTANT | NFT_SET_ANONYMOUS)))
 		return -EBUSY;
 
 	if (nla[NFTA_SET_ELEM_LIST_ELEMENTS] == NULL) {