Active Directory Authentication

Active Directory Authentication

This auth backend allows DokuWiki to authenticate against a Active Directory Server.

While Active Directory authentication can be set up with the default LDAP backend it should be easier to do with this dedicated auth backend. It makes use of the excellent adLDAP library and is based on the work by James Van Lommel. You do not need to download the adLDAP library yourself, it is included with DokuWiki.

In addition it allows the use of NTLM and Kerberos based Single-Sign-On .

This backend is included in DokuWiki since version rc2009-12-02 “Mulled Wine”.

You will also need to enable LDAP on the PHP server. LDAP is not enabled by default in PHP. This can be as easy as editing php.ini in most of the cases, however you might need to check your php installation to enable the LDAP support if you are using some specialty server installation.

Server Configuration

Your server configuration must meet the requirements of the adLDAP PHP library.

If you're using Apache on Ubuntu or Debian, just install the php5-ldap package. If you're using Apache on another distro, follow this guide.

If you're using a web server other than Apache, you have to figure it out yourself. :( Please update this article if you succeed.

Configuration

To avoid having them overridden by the config manager it is recommended to place the configuration in conf/local.protected.php.

You probably want to set at least these options:

 <?php
  // general DokuWiki options
  $conf['useacl']         = 1;
  $conf['disableactions'] = 'register';
  $conf['authtype']       = 'ad';
 
  // configure your Active Directory data here
  $conf['auth']['ad']['account_suffix']     = '@my.domain.org';
  $conf['auth']['ad']['base_dn']            = 'DC=my,DC=domain,DC=org';
  $conf['auth']['ad']['domain_controllers'] = 'srv1.domain.org, srv2.domain.org'; //multiple can be given

Optionally the following parameters can be given:

  $conf['auth']['ad']['ad_username']        = 'root';
  $conf['auth']['ad']['ad_password']        = 'pass';
  $conf['auth']['ad']['sso']                = 1;
  $conf['auth']['ad']['real_primarygroup']  = 1;
  $conf['auth']['ad']['use_ssl']            = 1;
  $conf['auth']['ad']['use_tls']            = 1;
  $conf['auth']['ad']['debug']              = 1;
  $conf['auth']['ad']['recursive_groups']   = 1; // If number of groups in AD is large switching to 0 will improve performance, but indirect membership will not work
  $conf['auth']['ad']['additional']         = 'department,office'; // additional attributes to fetch

ad_username and ad_password are e.g. required to enable user email subscriptions. This account binds to the AD for querying user details.

Use this code snippet in local.protected.php to set superuser rights:

$conf['manager']   = '@LDAPGROUPNAME';
$conf['superuser'] = '@LDAPGROUPNAME';

AD group names should be proceeded with ”@” and all spaces should be replaced with underscores. For example, if my AD group is called “Internal DokuWiki Admins”, it should be ”@Internal_DokuWiki_Admins” in DokuWiki. Any additional LDAP syntax is unneeded (e.g. all “CN=”, “DN=”, etc.). Only the name of the group is needed.

Any other options given in $conf['auth']['ad'] are directly passed to the adldap library. Please refer to the adLDAP documentation for a detailed description of what other options might be available.

In combination with Single-Sign-On, you can also add Windows domain specific setups. E.g. to authenticate against different Active Directory Servers depending on the NTLM or Kerberos Domain of a given user. The (lowercased) Domain just has to be used as a subkey to the $conf['auth']['ad'] setting. E.g. to identify all users coming from the Foobar Windows Domain using a non-default AD Server and user just put the following additional lines into your config:

$conf['auth']['ad']['foobar']['account_suffix']     = '@foobar.domain.org';
$conf['auth']['ad']['foobar']['base_dn']            = 'DC=foobar,DC=domain,DC=org';
$conf['auth']['ad']['foobar']['domain_controllers'] = 'otherad.domain.org';
$conf['auth']['ad']['foobar']['ad_username']        = 'otherroot';
$conf['auth']['ad']['foobar']['ad_password']        = 'otherpass';

If you have an organisation with multiple DCs under a single parent, you may need to connect to port 3268, rather than the default port 389. Otherwise, users from the remote DC may not show up as members of any groups. The easiest way to do this is to change adLDAP.php in the source code, because the base call to ldap_connect needs port as a separate argument.

User Profile and Password Changes

Users can change their user details (name, email and passwords) using the profile button. This may require to set up a privileged user through the ad_username and ad_password options. Password changing is only supported via SSL or TLS. See LDAP over SSL in the adLDAP documentation.

Please note that DokuWiki's auto generated passwords do not match with the Active Directory default password policy. Either adjust your AD password policy or disable the “Forget Password” option using the disableactions config option.

Group and User Names

Group and user names are cleaned up internally so they might differ from what is configured in your Active Directory server. Spaces are replaced with underscore and backslashes and hash symbols are removed.

Example: Domain Users becomes Domain_Users in DokuWiki. When you edit your ACLs manually, remember the correct encoding: Domain%5fUsers. The ”%5f” represents an underscore.

Keep this in mind when specifying users and groups in ACL setup or configuration.

Enabling SSO

Single Sign On (SSO) means that DokuWiki will use your Windows login name to identify you without the need for you to log in. This relies on the server setting the REMOTE_USER environment variable. The ad backend then will use this username to fetch additional data like your group membership.

To make this work you need to enable the sso setting in local.protected.php and most probably also need to setup a management account with enough permissions to fetch the user info:

$conf['auth']['ad']['sso'] = 1;
$conf['auth']['ad']['ad_username'] = 'MyManager';
$conf['auth']['ad']['ad_password'] = 'ManagerPass';

Additonally some setting have to be made for your server and the used Browser.

Web Server

NTLM on IIS

First configure IIS to use the Windows Logon for authentication (see screenshots):

Open the IIS configuration console using “Start” → “Run” → inetmgr
Right click on the “Default Web Site” entry and choose “Properties”
Switch to the “Directory Security” tab
Click the “Edit” button on “Anonymous access and authentication control”.
Disable “Anonymous access”
Enable “Integrated Windows Authentication”

Then make sure NTLM is used as authentication protocol. This has to be done on the commandline:

Open a command line: “Start” → “Run” → cmd
Change to the admin script directory: cd \Inetpub\Adminscripts
Check the current protocol: cscript adsutil.vbs get w3svc/NTAuthenticationProviders
if it doesn't say NTLM, set it: cscript adsutil.vbs set w3svc/NTAuthenticationProviders “NTLM”

Now restart IIS.

NTLM on Apache (Windows)

Download http://sourceforge.net/projects/mod-auth-sspi/ Copy the mod_auth_sspi.so file into your apache modules directory. Add into httpd.conf:

LoadModule sspi_auth_module modules/mod_auth_sspi.so 

<Directory "c:/wamp/www/">
    AuthName "My Intranet"
    AuthType SSPI
    SSPIAuth On
    SSPIAuthoritative On

    require valid-user

</Directory>

Now restart Apache

NTLM on Apache (Linux)

FIXME add info about mod_ntlm and similar here

Kerberos on Apache (Linux)

This setup enables an Apache Server on Linux to verify Kerberos Tickets against an Active Directory server.

Good references for Apache/Kerberos can be found at

The following examples assume your wiki to be running on dokuwiki.yourdomain.com, with your Active Directory server running at dc1.yourdomain.com;

Note: Kerberos is case sensitive, if it is all caps - it should be!

Install Kerberos client¹⁾
Install mod_auth_kerb²⁾

Configure Kerberos if necessary, sample /etc/krb5.conf:

[logging]
 default = FILE:/var/log/krb5libs.log
 kdc = FILE:/var/log/krb5kdc.log
 admin_server = FILE:/var/log/kadmind.log

[libdefaults]
 default_realm = YOURDOMAIN.COM
 ticket_lifetime = 24h
 forwardable = yes

[realms]
 YOURDOMAIN.COM = {
  kdc = dc1.yourdomain.com
  admin_server = dc1.yourdomain.com
  default_domain = yourdomain.com
 }

[domain_realm]
 dokuwiki.yourdomain.com = YOURDOMAIN.COM
 .yourdomain.com = YOURDOMAIN.COM
 yourdomain.com = YOURDOMAIN.COM

[appdefaults]
 pam = {
  debug = false
   ticket_lifetime = 36000
   renew_lifetime = 36000
   forwardable = true
   krb4_convert = false
 }

Verify that the time on the DokuWiki server is within 5 minutes of the Active Directory server. Otherwise Kerberos will not authenticate.

Verify that the Kerberos environment is working by running:

kinit username@YOURDOMAIN.COM
klist
kdestroy
(If you get any errors here, make sure your DNS setup is working and you wrote all marked as "YOURDOMAIN.COM" hosts in uppercase in your krb5.conf. Try resolve every hostname manually.

Create a keytab file for your DokuWiki server. Make sure you have created a non-admin user in Active Directory with no password expiration. Run this as a Domain Admin on a Windows server with Support Tools installed:

ktpass -princ HTTP/dokuwiki.yourdomain.com@YOURDOMAIN.COM -mapuser name_of_ad_user_you_have_created -crypto DES-CBC-MD5 -ptype KRB5_NT_PRINCIPAL -mapop set +desonly -pass the_ad_users_password -out dokuwiki.HTTP.keytab

Use the following if you're running Windows 7/Server 2008 R2 clients because des is disabled by default on these operating systems:

ktpass -princ HTTP/dokuwiki.yourdomain.com@YOURDOMAIN.COM -mapuser name_of_ad_user_you_have_created@yourdomain.com -crypto RC4-HMAC-NT -ptype KRB5_NT_PRINCIPAL -pass the_ad_users_password -out dokuwiki.HTTP.keytab

RC4-HMAC is supported on Windows 2000 and higher.

If no errors occurred, copy the keytab file to /etc/httpd/conf/.

Create /etc/httpd/conf.d/dokuwiki.conf:

<Directory "/var/www/html/dokuwiki">
        # Kerberos Auth
        AuthType Kerberos
        KrbAuthRealms YOURDOMAIN.COM
        KrbServiceName HTTP
        Krb5Keytab /etc/httpd/conf/dokuwiki.HTTP.keytab
        KrbMethodNegotiate on
        KrbMethodK5Passwd on
        require valid-user
</Directory>

(Re)start Apache: service httpd restart.

Troubleshooting

Restart Apache. Web server config changes won't apply until restarted.
Try using the FQDN of the DokuWiki server, i.e. http://dokuwiki.yourdomain.com/dokuwiki.
If you are presented with a login window, do not enter domain/realm info, just user name and password.
Verify that the time on the DokuWiki server is within 5 minutes of the Active Directory server. Otherwise Kerberos will not authenticate.
Check all Kerberos files for case inconsistencies.
Review this instruction from start to end. See reference links where possible.

Browser

Your browser needs to be setup to forward authentication info to the Webserver.

Setup MS Internet Explorer

FIXME add detailed description

add dokuwiki server to trusted zone
Enable authentication forwarding (Windows Integrated Authentication). Restart your browser to complete the change. IE 8 shown here:

Setup Firefox

Open Firefox and type about:config in the address bar.
In the ‘Filter’ field type one of the following (depending if you're using NTLM or Kerberos) network.automatic-ntlm-auth.trusted-uris or network.negotiate-auth.trusted-uris
Double click the name of the preference that we just searched for
Enter the URLs of the sites you wish to pass NTLM auth info to in the form of:

    http://intranet.company.com,http://email.company.lan

Notice that you can use a comma separated list in this field.

Effect on Plug-Ins

Some plug-ins may not gracefully work once you've switched over to the ad auth backend. Specifically, pulling the user's display name will not work if you don't provide valid authentication information. One such plugin is WikiStatistics, where a simple workaround to only display the username can be employed.

Due to missing support for paged queries in PHP's LDAP extension, plugins that try to get all users from the auth backend will fail if you use AUTH:AD and have more than 1000 objects in Active Directory. One example is the IssueTracker plugin.

¹⁾ Redhat: yum install krb5-workstation, Debian: krb5-user

²⁾ Redhat: yum install mod_auth_kerb, Debian: libapache2-mod-auth-kerb