You can add below hooks to add your own logo and link to replace default wordpress logo.
To add custom logo
function custom_login_logo() {
echo '<style type="text/css">
h1 a { background-image: url('.get_bloginfo('template_directory').'/images/custom-logo.png) !important; background-size : 100% !important; width: 300px !important; height : 100px !important;}
</style>';
}
add_action('login_head', 'custom_login_logo');
To add custom logo link
add_filter( 'login_headerurl', 'custom_loginlogo_url' );
function custom_loginlogo_url($url) {
return home_url();
}