phpLDAPadmin and Kerberos
I’ve been experimenting with phpLDAPadmin for browsing/searching LDAP directories over the web and found it to be a wonderful tool. I’m currently working with LDAP in a central authentication system together with Kerberos and wanted to have a nice web interface for managing user information within the LDAP directory. phpLDAPadmin provides a very nice interface for browsing, searching, and updating entries which makes it a bit easier than working with the ldap* command line tools. Here’s my basic setup of phpLDAPadmin using Kerberos for authentication. This assumes you already have an LDAP/Kerberos setup working and are using Apache as your web server.
First step is to make sure you have
support compiled into the LDAP PHP extension
--with-ldap-sasl. Check out
phpinfo() and make sure you see
SASL Support Enabled under the LDAP
extension. If not re-compile PHP.
Grab a copy of phpLDAPadmin
here and untar into a
directory of your choice (/usr/local). Copy the config.php.example to
$ tar -xvxf phpldapadmin-x.x.x.tar.gz $ ln -s phpldapadmin-x.x.x phpldapadmin $ cd phpldapadmin $ cp config/config.php.example config/config.php
Edit config/config.php. A few options to define are as follows:
$ldapservers->SetValue($i,'server','name','My LDAP Server'); $ldapservers->SetValue($i,'server','host','ldap.host.com'); $ldapservers->SetValue($i,'server','port','389'); $ldapservers->SetValue($i,'server','auth_type','config'); $ldapservers->SetValue($i,'login','dn',''); $ldapservers->SetValue($i,'login','pass',''); $ldapservers->SetValue($i,'server','tls',false); $ldapservers->SetValue($i,'server','sasl_auth',true); $ldapservers->SetValue($i,'server','sasl_mech','GSSAPI'); $ldapservers->SetValue($i,'server','sasl_authz_id_regex','/^uid=([^,]+)(.+)/i'); $ldapservers->SetValue($i,'server','sasl_authz_id_replacement','$1'); $ldapservers->SetValue($i,'login','anon_bind',false);
Basically, we’re configuring phpLDAPadmin with
auth_type = config which means
that the user/pass used to bind to the LDAP server is hard coded in the
config.php file. We leave the user/pass blank because each user will first be
authenticating through Kerberos and using their tickets to bind to the LDAP
server. Internally phpLDAPadmin calls the ldap_sasl_bind(..)
function with an
which does the work of binding using Kerberos tickets.
Next, we’ll configure apache to point to the location where we installed phpLDAPadmin. Edit your httpd.conf file or equivalent. If your running redhat usually create a file in /etc/httpd/conf.d or on Debian /etc/apache2/site-available/. You will probably want to add this to an SSL vhost to ensure your username/passwords are transmitted over a secure connection.
Alias /ldapadmin /usr/local/phpldapadmin/htdocs/ <Location /ldapadmin> AuthType Kerberos AuthName "LDAP Admin" KrbAuthRealms kerb.yourhost.com KrbVerifyKDC off KrbServiceName HTTP Krb5KeyTab /path/to/your/httpd.keytab KrbSaveCredentials on require valid-user </Location>
In order to authenticate users against Kerberos and obtain the necessary
Kerberos tickets we use the apache module
mod_auth_kerb. The apache config above
defines our location for phpLDAPadmin and adds in the necessary config for
mod_auth_kerb. More info can be found
here. Make sure to add in
KrbSaveCredentails on directive so that mod_auth_kerb will save the
Kerberos tickets for use throughout the request.
Next we need to expose the location of the Kerberos tickets to phpLDAPadmin.
mod_auth_kerb sets an environment variable
KRB5CCNAME to the location of the
credential cache. To expose this environment variable to the phpLDAPadmin code
edit the file
[phpLDAPadmin_install]/lib/common.php and add this line to the
That should do it. Now when you access http://yourserver.com/ldapadmin you should be challenged with HTTP basic auth, which authenticates against Kerberos and uses the Kerberos credentials to bind to your LDAP server. There might be an easier way to go about doing this but I wasn’t able to turn much up on google so I thought I’d share one way I was able to get things working.