Cross-domain sessions with connect-mongo

I have built Node.js app with Express 4, for manage sessions I use connect-mongo middleware, all works.

But I need login to my app from another site.

App is hosted on aws EC2.

I use SalesForce and after login to it, I want open my app, but DON'T want input credentials...

On node.js server I have added headers:

res.setHeader('Access-Control-Allow-Origin', req.headers.origin);
res.setHeader('Access-Control-Allow-Credentials', 'true');

In SF, onClick button I execute:

jsonData = {
    "email": 'test1@example.com',
    "password": "test"
}
$.ajaxSetup({
    type: "POST",
    data: {},
    dataType: 'json',
    xhrFields: {
       withCredentials: true
    },
    crossDomain: true
});



$.post( 'http://ec2-someip.us-west-2.compute.amazonaws.com//login', jsonData)
.done(function( data ) {
    console.log( "done" );

    console.log(data);
    //redirect to data url
})
.fail(function(data) {
    console.log( "error" );
    console.log( "data" );
});

Node.js returns me correct data url, but doesn't add session cookie, and that's why I see login page after redirect...

When I manually send POST request from browser (I use "Rest Console" app for Google Chrome), node.js added cookie.

What is wrong? There is a way to login from SF (or any other site) ?

Thank you.