VCL 2.2.1 - Adding LDAP Authentication

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. On CentOS, information about the certificate needs to be added to /etc/pki/tls/certs/ca-bundle.crt - this script will take as input a file containing the base64 encoded certificate and generate the lines that need to be added to the ca-bundle.crt file.

• After adding the certificate, restart httpd: {tip} service httpd restart {tip}

• You can verify that the certificate is properly installed using this command: {tip} openssl s_client -showcerts -CAfile /etc/pki/tls/certs/ca-bundle.crt -connect your.ldap.server.here:636 {tip} 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. 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. {tip} mysql vcl {tip} {tip} INSERT INTO affiliation (name) VALUES (‘EXAMPLE’); {tip} {tip} SELECT id FROM affiliation WHERE name = ‘EXAMPLE’; {tip} {tip} exit {tip}
• 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 ** 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 ** 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

Tweak if your LDAP server has users in multiple containers

If your LDAP server has users in multiple containers, then the full DN for each user must be looked up before doing a bind to the LDAP server to authenticate the user. In this case, you’ll need to modify authentication.php.

• Edit authenciation.php
• Search for “ldapLogin”
• Search for “EXAMPLE1 LDAP” in the function
• Uncomment the block of code it is contained in by removing the ‘/’ at the beginning of the line containing ‘EXAMPLE1 LDAP’, and removing the ‘/’ at the end of the else that is before ‘$ldapuser = sprintf($authMechs[](.html) [‘userid’], $userid);’
• change ‘EXAMPLE1 LDAP’ to match what you changed it to in step 3
• Look for the line containing ‘cn=$userid’. If you use ‘cn’ to look up userids in your LDAP server, the line is fine as is. If you use something else, such as ‘uid’, change ‘cn’ to ‘uid’ or whatever is used on your LDAP server.
• Save the file