netfilter: nf_tables: disallow timeout for anonymous sets

Never used from userspace, disallow these parameters.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nf_tables_api.c

@@ -4909,6 +4909,9 @@ static int nf_tables_newset(struct sk_buff *skb, const struct nfnl_info *info,
 		if (!(flags & NFT_SET_TIMEOUT))
 			return -EINVAL;
 
+		if (flags & NFT_SET_ANONYMOUS)
+			return -EOPNOTSUPP;
+
 		err = nf_msecs_to_jiffies64(nla[NFTA_SET_TIMEOUT], &desc.timeout);
 		if (err)
 			return err;
@@ -4917,6 +4920,10 @@ static int nf_tables_newset(struct sk_buff *skb, const struct nfnl_info *info,
 	if (nla[NFTA_SET_GC_INTERVAL] != NULL) {
 		if (!(flags & NFT_SET_TIMEOUT))
 			return -EINVAL;
+
+		if (flags & NFT_SET_ANONYMOUS)
+			return -EOPNOTSUPP;
+
 		desc.gc_int = ntohl(nla_get_be32(nla[NFTA_SET_GC_INTERVAL]));
 	}