Adding LDAP Authenciation

Prerequisites for your LDAP server:

  • SSL should be enabled on your LDAP server
  • An LDAP account that can look up a user's first and last names, user id, and email address (email address is optional) - this will be referred to as 'vcllookup' on this page. You can skip this step if anonymous binds are enabled on your LDAP server and an anonymous bind will be able to look up userids, names, and email addresses.
  • If your LDAP server is behind a firewall, you will need to allow your VCL web server to access tcp port 636 on your LDAP server

Prerequisites for your VCL web server:

  • php-ldap needs to be installed
  • If your LDAP server's SSL certificate is self-signed, your VCL web server needs to have the root CA certificate that was used to sign the LDAP server certificate installed. The PEM formatted certificate needs to be added to the ca-bundle.crt file. On CentOS, the file is located at /etc/pki/tls/certs/ca-bundle.crt. The hostname in the certificate must match the hostname entered in the conf.php file further down. If your certificate does not have the correct hostname in it, you can put an entry in /etc/hosts for the hostname in the certificate.
  • After adding the certificate, restart httpd:

    service httpd restart

  • You can verify that the certificate is properly installed using this command:

    openssl s_client -showcerts -CAfile /etc/pki/tls/certs/ca-bundle.crt -connect your.ldap.server.here:636

    If you see "Verify return code: 0 (ok)" at the end of the output then it is installed correctly. If you see a different return code, then you'll need to troubleshoot the problem.
  • You may need to add a line to /etc/openldap/ldap.conf to point to the ca-bundle.crt file. If so, add the following: 
    TLS_CACERT /etc/pki/tls/certs/ca-bundle.crt

Adding LDAP Authentication to the Web Code

  • You will need to manually add an entry to the affiliation table in the VCL database. Choose a name for the affiliation. This will be appended to all userids for the affiliation to distinguish them from other affiliations you may configure later. Do not use the Global affiliation for this. Initials or a short name of your organization are a good idea. The affiliation name cannot contain spaces. Use the following to add the affiliation, replacing 'EXAMPLE' with the name you chose. Take note of the id from the 2nd SQL statement as you will need it later. It is the numerical id for this affiliation.

    mysql vcl

    INSERT INTO affiliation (name) VALUES ('EXAMPLE');

    SELECT id FROM affiliation WHERE name = 'EXAMPLE';

    exit

  • Edit conf.php and search for "EXAMPLE1 LDAP"
  • Uncomment the "EXAMPLE1 LDAP" section by removing the '/*' before it and the '*/' at the end of 'to use this login mechanism'
  • Change 'EXAMPLE1 LDAP' to something to match your location, for example at NCSU, it is 'NCSU LDAP'. This string is what users will see where they select the authentication mechanism to use when logging in.
  • Modify the following fields:
    • server - this is the hostname of your LDAP server - this must match the hostname in the certificate.
    • binddn - typically, you'll want to use the base DN of your LDAP server; for Active Directory, this is usually dc= for each of your domain name components. For example, your your domain name was ad.example.org, it would be "dc=ad,dc=example,dc=org"
    • userid - this is a string that is added to the userid a user enters on the login page. Place a '%s' where the entered userid should go. Some examples are:
      • %s@example.org
      • %s@ad.example.org
      • uid=%s,ou=accounts,dc=example,dc=org'
    • unityid - this is the ldap field that contains a user's login id (for Active Directory, this is usually sAMAccountName)
    • firstname - this is the ldap field that contains a user's first name
    • lastname - this is the ldap field that contains a user's last name
    • email - this is the ldap field that contains a user's email address
    • defaultemail - if an email address is not provided by the ldap server, this will be appended to the end of the userid to create an email address. In this case, email notifications will be disabled by default.
    • masterlogin - this is the vcllookup account referred to in the "Prerequisites for your LDAP server" section - comment out this line if using anonymous binds
    • masterpwd - password for the masterlogin account - comment out this line if using anonymous binds
    • affiliationid - this is the id from the SELECT statement in the first step
    • lookupuserbeforeauth - Some LDAP servers will only allow the full DN of a user to be used when authenticating. If this is the case, you will need to set this to 1 and set a value for lookupuserfield. You can probably start out with this set to 0. If your LDAP server has users in multiple containers, you will probably need to set this to 1.
    • lookupuserfield - If you need to set lookupuserbeforeauth to 1, set this to the attribute to use to search for the user in ldap. Typical values are 'cn', 'uid', and 'samaccountname'.
    • help - this is some text that will show up on the page where users select the authentication method explaining why they would select this option
  • Uncomment the require_once line for ldapauth.php toward the bottom of the file
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