LDAP Authentication

Requirements

  • PHP LDAP extension enabled

  • LDAP server: - OpenLDAP - Microsoft Active Directory - Novell eDirectory

Workflow

When the LDAP authentication is activated, the login process works like that:

  1. Try first to authenticate the user by using the database

  2. If the user is not found inside the database, a LDAP authentication is performed

  3. If the LDAP authentication is successful, by default a local user is created automatically with no password and marked as LDAP users.

The full name and the email address are automatically fetched from the LDAP server.

Authentication Types

Type

Description

Proxy User

A specific user is used to browse LDAP directory

User

The end-user credentials are used for browsing LDAP directory

Anonymous

No authentication is performed for LDAP browsing

Note

The recommended authentication method is Proxy.

Anonymous Mode

define('LDAP_BIND_TYPE', 'anonymous');
define('LDAP_USERNAME', null);
define('LDAP_PASSWORD', null);

This is the default value but some LDAP servers don’t allow anonymous browsing for security reasons.

Proxy Mode

A specific user is used to browse the LDAP directory:

define('LDAP_BIND_TYPE', 'proxy');
define('LDAP_USERNAME', 'my proxy user');
define('LDAP_PASSWORD', 'my proxy password');

User Mode

This method uses the credentials provided by the end-user.

For example, Microsoft Active Directory doesn’t allow anonymous browsing by default and if you don’t want to use a proxy user you can use this method.

define('LDAP_BIND_TYPE', 'user');
define('LDAP_USERNAME', '%s@kanboard.local');
define('LDAP_PASSWORD', null);

In this case, the constant LDAP_USERNAME is used as a pattern to the ldap username, examples:

  • %s@kanboard.local will be replaced by my_user@kanboard.local

  • KANBOARD\\%s will be replaced by KANBOARD\my_user

User LDAP filter

The configuration parameter LDAP_USER_FILTER is used to find users in LDAP directory.

Examples:

  • (&(objectClass=user)(sAMAccountName=%s)) is replaced by (&(objectClass=user)(sAMAccountName=my_username))

  • uid=%s is replaced by uid=my_username

Other examples of filters for Active Directory

Example to filter access to Kanboard:

(&(objectClass=user)(sAMAccountName=%s)(memberOf=CN=Kanboard Users,CN=Users,DC=kanboard,DC=local))

This example allows only people members of the group “Kanboard Users” to connect to Kanboard.

Example for Microsoft Active Directory

Let’s say we have a domain KANBOARD (kanboard.local) and the primary controller is myserver.kanboard.local.

First example with proxy mode:

<?php

// Enable LDAP authentication (false by default)
define('LDAP_AUTH', true);

define('LDAP_BIND_TYPE', 'proxy');
define('LDAP_USERNAME', 'administrator@kanboard.local');
define('LDAP_PASSWORD', 'my super secret password');

// LDAP server hostname
define('LDAP_SERVER', 'myserver.kanboard.local');

// LDAP properties
define('LDAP_USER_BASE_DN', 'CN=Users,DC=kanboard,DC=local');
define('LDAP_USER_FILTER', '(&(objectClass=user)(sAMAccountName=%s))');

Second example with user mode:

<?php

// Enable LDAP authentication (false by default)
define('LDAP_AUTH', true);

define('LDAP_BIND_TYPE', 'user');
define('LDAP_USERNAME', '%s@kanboard.local');
define('LDAP_PASSWORD', null);

// LDAP server hostname
define('LDAP_SERVER', 'myserver.kanboard.local');

// LDAP properties
define('LDAP_USER_BASE_DN', 'CN=Users,DC=kanboard,DC=local');
define('LDAP_USER_FILTER', '(&(objectClass=user)(sAMAccountName=%s))');

Example for OpenLDAP

Our LDAP server is myserver.example.com and all users are stored under ou=People,dc=example,dc=com.

For this example we use the anonymous binding.

<?php

// Enable LDAP authentication (false by default)
define('LDAP_AUTH', true);

// LDAP server hostname
define('LDAP_SERVER', 'myserver.example.com');

// LDAP properties
define('LDAP_USER_BASE_DN', 'ou=People,dc=example,dc=com');
define('LDAP_USER_FILTER', 'uid=%s');

Example for LDAPS (SSL-encryption)

Some LDAP servers are configured for “LDAPS” connectivity only (on port 636). This is different to TLS, which starts off in cleartext (port 389 by default) and then sets up encryption over the same channel.

To tell PHP to use LDAPS, you need to prefix the name of your LDAP server with “ldaps://”, as in the example below:

Our LDAP server is myserver.example.com and is only accessible via LDAPS. Most likely we won’t want to validate the server cert, and we DON’T want TLS.

For this example we use the anonymous binding.

<?php

// Enable LDAP authentication (false by default)
define('LDAP_AUTH', true);

// LDAP server hostname
define('LDAP_SERVER', 'ldaps://myserver.example.com');

// By default, require certificate to be verified for ldaps:// style URL. Set to false to skip the verification
define('LDAP_SSL_VERIFY', false);

// Enable LDAP START_TLS
define('LDAP_START_TLS', false);;

Disable Automatic Account Creation

By default, Kanboard will create a user account automatically if nothing is found.

You can disable this behavior if you prefer to create user accounts manually to restrict Kanboard to only some people.

Change the value of LDAP_USER_CREATION to false:

// Automatically create user account
define('LDAP_USER_CREATION', false);

Synchronization

By default, Kanboard will synchronize all fields (role, name, email…) except the username.

If you would like to change this behavior, use this config parameter:

// This example will not synchronize the fields "username" and "role" from LDAP to Kanboard.
define('EXTERNAL_AUTH_EXCLUDE_FIELDS', 'username,role');

Troubleshooting

SELinux Restrictions

If SELinux is enabled, you have to allow Apache to reach out your LDAP server.

  • You can switch SELinux to the permissive mode or disable it (not recommended)

  • You can allow all network connections, for example setsebool -P httpd_can_network_connect=1 or have a more restrictive rule

In any case, refer to the official Redhat/Centos documentation.

Debug Mode

If you are not able to setup correctly the LDAP authentication, you can enable the debug mode and watch log files.