if ( isset ($_POST['post_password'] ) ) custom_postpass_check();

function custom_password_form( $out ) {
    $out = str_replace('wp-login.php', '', $out);
    return $out;
}
add_filter( 'the_password_form', 'custom_password_form', 10, 1 );

function custom_postpass_check(){
	$secure = ( 'https' === parse_url( wp_login_url(), PHP_URL_SCHEME ) );
	if ( ! array_key_exists( 'post_password', $_POST ) ) {
		wp_safe_redirect( wp_get_referer() );
		exit();
	}

	$hasher = new PasswordHash( 8, true );

	$expire = apply_filters( 'post_password_expires', time() + 10 * DAY_IN_SECONDS );
	$referer = wp_get_referer();
	if ( $referer ) {
		$secure = ( 'https' === parse_url( $referer, PHP_URL_SCHEME ) );
	} else {
		$secure = false;
	}
	setcookie( 'wp-postpass_' . COOKIEHASH, $hasher->HashPassword( wp_unslash( $_POST['post_password'] ) ), $expire, COOKIEPATH, COOKIE_DOMAIN, $secure );

	wp_safe_redirect( wp_get_referer() );
	exit();
}