Web SSO - part 2 - integration with LDAP

In my previous article I presented how to create a web SSO system using SimpleSAMLphp and Symfony. The users where declared directly in simpleSAMLphp using "exampleauth:UserPass".

In many companies a LDAP server is the source from where information about user authentication is taken. I will install  OpenLDAP and configure my applications to use it.

1. Install OpenLDAP and phpLDAPadmin

For installing OpenLDAP and phpLDAPadmin I followed this tutorials from DigitalOcean:

https://www.digitalocean.com/community/tutorials/how-to-install-and-configure-openldap-and-phpldapadmin-on-an-ubuntu-14-04-server

You will need to edit also the ldap.conf file, see this thread on StackOverflow

Also you may get an error when trying to login with phpLDAPadmin  "Notice: Undefined variable: _SESSION in ..". 
For me this solution from StackOverflow solved the problem:

"Just add the user wich is running Apache2 (or php5-fpm!) to the system group "www-data" (debian) and restart services apache AND if used php5-fpm both.
Get the User apache is running as:

~# sed -rn 's/^User (.+)/\1/p' /etc/apache2/apache2.conf"

Using phpLDAPadmin I've created two groups "admin" and "regular_users" and also I've created some users allocated to these two groups.

2. Modify SimpleLDAPphp to use OpenLDAP

The documentation for using LDAP authentication is found here: https://simplesamlphp.org/docs/stable/ldap:ldap

My settings are:


Select LDAP authentication to be used from   /metadata/saml20-idp-hosted.php

 /* 
         *Authentication source to use. Must be one that is configured in
* 'config/authsources.php'.
*/
'auth' => 'example-ldap',

3. Modify Symfony app

In the current Symfony application I am expecting an attribute roles containing an array of roles. From LDAP I will receive different attributes, one of them is gidNumber, which is a number identifying a group. My current groups: admin and regular_users have gidNumber 500 and 501.
I will be using these gidNumbers to correctly create roles in the Symfony application.

The changes to be made are done in the UserCreator class:

Of course you need to change these mappings to fit your situation.

4. Test

First make sure to delete any sessions and cookies. After that try to access the secure route from consumer1.local, login with any user from LDAP and you should be redirected to secure area. Check in database if the user and user roles were created correctly.