netfilter: nft_dynset: disallow object maps

jira VULN-430
cve CVE-2023-4244
commit-author Pablo Neira Ayuso <pablo@netfilter.org>
commit 23185c6

Do not allow to insert elements from datapath to objects maps.

Fixes: 8aeff92 ("netfilter: nf_tables: add stateful object reference to set elements")
	Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
	Signed-off-by: Florian Westphal <fw@strlen.de>
(cherry picked from commit 23185c6)
	Signed-off-by: Marcin Wcisło <marcin.wcislo@conclusive.pl>

Author: pvts-mat

net/netfilter/nft_dynset.c

@@ -191,6 +191,9 @@ static int nft_dynset_init(const struct nft_ctx *ctx,
 	if (IS_ERR(set))
 		return PTR_ERR(set);
 
+	if (set->flags & NFT_SET_OBJECT)
+		return -EOPNOTSUPP;
+
 	if (set->ops->update == NULL)
 		return -EOPNOTSUPP;