netfilter: nf_tables: allow to fetch set elements when table has an owner

jira VULN-430
cve-pre CVE-2023-4244
commit-author Pablo Neira Ayuso <pablo@netfilter.org>
commit 92f3e96

NFT_MSG_GETSETELEM returns -EPERM when fetching set elements that belong
to table that has an owner. This results in empty set/map listing from
userspace.

Fixes: 6001a93 ("netfilter: nftables: introduce table ownership")
	Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
(cherry picked from commit 92f3e96)
	Signed-off-by: Marcin Wcisło <marcin.wcislo@conclusive.pl>

Author: pvts-mat

net/netfilter/nf_tables_api.c

@@ -5525,7 +5525,7 @@ static int nf_tables_getsetelem(struct sk_buff *skb,
 	int rem, err = 0;
 
 	table = nft_table_lookup(net, nla[NFTA_SET_ELEM_LIST_TABLE], family,
-				 genmask, NETLINK_CB(skb).portid);
+				 genmask, 0);
 	if (IS_ERR(table)) {
 		NL_SET_BAD_ATTR(extack, nla[NFTA_SET_ELEM_LIST_TABLE]);
 		return PTR_ERR(table);