netfilter: nf_tables: Release memory obtained by kasprintf

Free memory region, if nf_tables_set_alloc_name is not successful.

Fixes: 387454901bd6 ("netfilter: nf_tables: Allow set names of up to 255 chars")
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nf_tables_api.c

@@ -2741,8 +2741,10 @@ cont:
 	list_for_each_entry(i, &ctx->table->sets, list) {
 		if (!nft_is_active_next(ctx->net, i))
 			continue;
-		if (!strcmp(set->name, i->name))
+		if (!strcmp(set->name, i->name)) {
+			kfree(set->name);
 			return -ENFILE;
+		}
 	}
 	return 0;
 }