netfilter: nf_tables: introduce nft_validate_register_load()

Change nft_validate_input_register() to not only validate the input
register number, but also the length of the load, and rename it to
nft_validate_register_load() to reflect that change.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/net/netfilter/nft_lookup.c b/net/netfilter/nft_lookup.c
index 3574543..8fc0d18 100644
--- a/net/netfilter/nft_lookup.c
+++ b/net/netfilter/nft_lookup.c
@@ -71,7 +71,7 @@
 	}
 
 	priv->sreg = ntohl(nla_get_be32(tb[NFTA_LOOKUP_SREG]));
-	err = nft_validate_input_register(priv->sreg);
+	err = nft_validate_register_load(priv->sreg, set->klen);
 	if (err < 0)
 		return err;