netfilter: nf_tables: reject NFT_SET_CONCAT with not field length description

BugLink: https://bugs.launchpad.net/bugs/2055145

[ Upstream commit 113661e ]

It is still possible to set on the NFT_SET_CONCAT flag by specifying a
set size and no field description, report EINVAL in such case.

Fixes: 1b6345d ("netfilter: nf_tables: check NFT_SET_CONCAT flag if field_count is specified")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Manuel Diewald <manuel.diewald@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

Author: ummakynes

net/netfilter/nf_tables_api.c

@@ -4703,8 +4703,12 @@ static int nf_tables_newset(struct sk_buff *skb, const struct nfnl_info *info,
 		if (err < 0)
 			return err;
 
-		if (desc.field_count > 1 && !(flags & NFT_SET_CONCAT))
+		if (desc.field_count > 1) {
+			if (!(flags & NFT_SET_CONCAT))
+				return -EINVAL;
+		} else if (flags & NFT_SET_CONCAT) {
 			return -EINVAL;
+		}
 	} else if (flags & NFT_SET_CONCAT) {
 		return -EINVAL;
 	}