php, 105 bytes

Result

AC

Duration

966ms

Code [DL]

<?php $h=+fgets(STDIN);$w=fgets(STDIN)-2;for($y=$h;$y;)echo"*".str_repeat($y--<$h&&$y?" ":"*",$w)."*\n"?>

stdin

29
18

stdout

******************
*                *
*                *
*                *
*                *
*                *
*                *
*                *
*                *
*                *
*                *
*                *
*                *
*                *
*                *
*                *
*                *
*                *
*                *
*                *
*                *
*                *
*                *
*                *
*                *
*                *
*                *
*                *
******************

stderr

PHP Notice:  A non well formed numeric value encountered in /volume/CODE on line 1
PHP Notice:  A non well formed numeric value encountered in /volume/CODE on line 1