netfilter: nf_tables: fix overrun in nf_tables_set_alloc_name()

The map that is used to allocate anonymous sets is indeed
BITS_PER_BYTE * PAGE_SIZE long.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nf_tables_api.c

@@ -1989,13 +1989,13 @@ static int nf_tables_set_alloc_name(struct nft_ctx *ctx, struct nft_set *set,
 
 			if (!sscanf(i->name, name, &tmp))
 				continue;
-			if (tmp < 0 || tmp > BITS_PER_LONG * PAGE_SIZE)
+			if (tmp < 0 || tmp >= BITS_PER_BYTE * PAGE_SIZE)
 				continue;
 
 			set_bit(tmp, inuse);
 		}
 
-		n = find_first_zero_bit(inuse, BITS_PER_LONG * PAGE_SIZE);
+		n = find_first_zero_bit(inuse, BITS_PER_BYTE * PAGE_SIZE);
 		free_page((unsigned long)inuse);
 	}