kotlin, 127 bytes

Result

AC

Duration

4825ms

Code [DL]

fun r()=readLine()!!.toInt()-2
fun main(){var h=r()
var w=r()
for(c in "*"+" ".repeat(h)+"*")println("*"+(""+c).repeat(w)+"*")}

stdin

10
15

stdout

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

stderr