Background: I am trying to set up single sign on (SSO) for users such that they can authenticate to my website and not have to authenticate a second time to our third-party MSP's website. Ideally, the user clicks a link on our website and is taken to the third-party site already logged in and landing on the dashboard (if the account doesn't exist, it is created during this step). We are not using SAML for authentication as a security feature, so all that we need the SAML code for is just producing cookies that prevent the user from having to log in again when he/she gets to our vendor's site. This third party MSP does not support authentication via API or web service and therefore I have been tasked with implementing SAML, their only supported SSO method. I am new to SAML (but not PHP or development) and have been learning as I go. I am told it will support the goals described above.
I initially tried using LDAP as the authentication source as this is what I use for authentication to my website, but this resulted in me getting directed to a login page with no discernible way to instead just pass parameters to SimpleSAMLphp to tell it "the user is already authenticated, all I need you to do is give me valid cookies so I can get past the third party website's authentication checks".
So I switched to writing a custom authentication module. I opened up the GitHub for SimpleSAMLphp and used the "UserPassBase" class as an example to create my own authentication module that inherits from the "Source" class. Because I don't need to re-authenticate the user against LDAP a second time since they're already logged in to our website, I created a simple "authenticate" function that just sets the $state['Attributes'] array.
Here is the code for my custom module:
<?php
namespace SimpleSAML\Module\productauth\Auth\Source;
use SimpleSAML\Auth;
/**
Author: Joey
Class developed to be used as a custom authentication module for simpleSAMLphp. This class will take an existing session from a product website and use it to create a SAML session and redirect to a website.
**/
class ProductAuth extends \SimpleSAML\Auth\Source {
const STAGEID = '\SimpleSAML\Module\productauth\Auth\ProductAuth.state';
const AUTHID = '\SimpleSAML\Module\productauth\Auth\ProductAuth.AuthId';
private $user;
public function __construct($info, $config) { // parameters aren't used, just filler from base class
$info = array("AuthId" => "productauth");
parent::__construct($info, $config);
}
public function login($user, $redirectURL) {
$this->user = $user; // normally I'd set this in the constructor, but the overload has my hands tied as far as function definitions go
$this->initLogin($redirectURL); // calls authenticate function and then, if no exceptions, parent::loginCompleted which redirects to the given URL
}
public function authenticate(&$state) { // called by parent::initLogin
$state[self::AUTHID] = $this->authId;
$state['Attributes'] = [
'uid' => [$this->user->uid],
'givenName' => [$this->user->givenName],
'sn' => [$this->user->sn],
'mail' => [$this->user->mail]
];
$id = Auth\State::saveState($state, self::STAGEID);
}
}
?>
I am calling it from a controller class on my website:
private function goToTrainingSite() {
require_once("../third-party-libs/simplesamlphp/_include.php");
global $TRAINING_URL;
$user = $_SESSION['subject']->user;
$samlObj = new SimpleSAML\Module\productauth\Auth\Source\ProductAuth(array(), array());
$samlObj->login($user, $TRAINING_URL);
}
I mimicked the flow of the "UserPassBase" class (https://github.com/simplesamlphp/simplesamlphp/blob/master/modules/core/lib/Auth/UserPassBase.php), but it seems that despite all of my authentication working and setting a SimpleSAMLAuth cookie, when the parent::loginCompleted function in the "Source" class (https://github.com/simplesamlphp/simplesamlphp/blob/master/lib/SimpleSAML/Auth/Source.php) runs, it redirected me to the third party site. I then see the following in the logs:
SAML2.0 - IdP.SSOService: incoming authentication request: [REDACTED DATA]
Session: 'productauth' not valid because we are not authenticated.
I have been trying for 3 days to figure out why it seems as though despite setting SimpleSAML session cookies with a completed, successful authentication, that upon receiving the auth request from the SP, my SimpleSAMLphp code just pretends to not know about the completed auth and tries to authenticate again... but because it is not being called from my code, it doesn't have access to the $user variable which contains all of the attributes I need to place on the user when he/she authenticates to this third party website. It seems that when it receives an authentication request, my SimpleSAMLphp installation starts a new session and tries a brand new authentication.
I have delved into a lot of the code of SimpleSAMLphp and tried to understand what is going on, but it seems that there is just no reasonable way to authenticate by calling an authentication source from PHP code and being able to skip the SP-initiated authentication. I have tried:
- Using the SimpleSAML API (https://simplesamlphp.org/docs/stable/simplesamlphp-sp-api) to call my authentication source, but there seems to be no way to pass that $user variable I need the attributes from.
- Trying to load the cookies in the "Session" class when it is checking for valid sessions... but it seems like the cookies from the successful auth session initiated by my code are just gone and nowhere to be found.
