CORS request with IE11

Question

I have a CORS (cross origin resource sharing) request coming from my login page to the application site, on a different URL. I have a simple page I ping to determine if a user is already logged in, and if so, redirects them. Otherwise I show a login page. I use jQuery.

This works great in safari, chrome, firefox... and not IE (naturally). According to MS, IE 10 and later should support CORS requests with withCredentials

I'm using jquery-2.0.3.min.js

Any ideas why this isn't working in IE11?

EDIT: It appears as though it IS partially working, as it is now returning a value of {"id":false}. This happens every time, meaning that the server is never getting the credentials. I am also posting my is_logged_in page, I am using the code igniter framework.

EDIT: After enabling "Allow data sources across domains" under IE's security settings, I no longer receive any error messages.

The exact error I receive is:

SEC7118: XMLHttpRequest for http://mysite.net/guest/is_logged_in required Cross Origin Resource Sharing (CORS).

$.ajax({
url: 'http://mysite.net/guest/is_logged_in',
type: 'POST',
crossDomain: true,
xhrFields: {
       withCredentials: true
  },

dataType: 'json',
success: function(data) {

    if(data.id) {
        window.location.replace("http://mysite.net");
    }
}
});

and

public function is_logged_in()
{
    $allowed = array(
        'http://mysite.net',
        'http://www.mysite.net',
        'http://www.mysite.com',
    );

    $url = $_SERVER['HTTP_REFERER'];
    $url = substr($url, 0, strpos($url, '/', 8));
    if(isset($_SERVER['HTTP_ORIGIN']))
    {
        if(in_array($_SERVER['HTTP_ORIGIN'], $allowed))
        {
            $this->output->set_header('Access-Control-Allow-Origin: ' . $_SERVER['HTTP_ORIGIN']);
        }
    }
    else
    {
        if(in_array($url, $allowed))
        {
            $this->output->set_header('Access-Control-Allow-Origin: ' . $url);
        }
    }


    $this->output->set_header('Access-Control-Allow-Headers: X-Requested-With');
    $this->output->set_header('Access-Control-Allow-Credentials: true');
    $this->output->set_header("Access-Control-Expose-Headers: Access-Control-Allow-Origin");


    //TODO: Try to detect if this is an ajax request, and disallow it if not.

    $data = new stdClass();
    $this->load->library("ion_auth");
    if($this->ion_auth->logged_in())
    {
        $data->name = $this->ion_auth->user()->row()->first_name;
        $data->id = $this->ion_auth->get_user_id();
    } else {
        $data->id = false;
    }

    $this->output->set_output(json_encode($data));

}

Thanks in advance

Answer 1

Changing the setting for "Access data sources across domains" to Enabled turns off cross-domain checks in IE and is horrifically unsafe. Instead, you need to ensure that the target 3rd-party resource sends a valid P3P policy that indicates that it's not doing horrible things to the user's privacy.