Own logo and logo link on WordPress login

you can do this via functions.php file of your child theme:

function custom_login_logo() {
    echo '<style type="text/css">
    h1 a { background-image:url( link-to-your-logo) !important;
    background-size:300px auto !important; 
    height: 120px !important; 
    width: 300px !important }
    </style>';
}
add_action('login_head', 'custom_login_logo');

on default the logo goes to wordpress page – you can link to what ever you like

add_filter( 'login_headerurl', 'custom_loginlogo_url' );
function custom_loginlogo_url($url) {
  return 'https://url-you-like';
}

the height has to be adjusted to your logo dimensions