LdapAuthenticator for Nette

The LDAP/Active Directory authenticator plugin for Nette Framework.

Supported out of the box:

• LDAP Authentication (obviously)
• User information loading, including user picture in AD
• User groups membership, including group inheritance. (groupA member of groupB, which is member of groupC? No problem!)
• Groups whitelist for login (aka "allowLogin")
• Groups blacklist for login (aka "refuseLogin")
• Admin role appender - user will have "admin" role, if he's present in some of the specified LDAP groups
• Groups-to-roles mapping based on group DN, name and/or e-mail address
• Post-processing data before identity creation based on Callbacks
  • used for loading of user database id and more
• Identity generator from loaded data, based on callback - don't like default behaviour? Rewrite it!
• Username generator based on callback - following logins are valid by default:
  • name.surname
  • name.surname@yourdomain.com
• Success login handlers for integrating the LDAP into your application. In example, this is used for both userdata loading from LDAP (thumbnails, name & surname, etc.), and for loading the ID from database (so that your database model can work seamlessly with LDAP.)

Include once, extend forever. Under MIT license.

Install

$ composer require foglcz/ldap-authenticator

Use

1. Open app/model/UserManager.php and remove the implements Nette\Security\IAuthenticator

2. Open app/config/config.neon file and change default UserManager definition.

   services:
   	- App\Model\UserManager
   

   becomes:

   services:
   	userManager: App\Model\UserManager
   

3. Open app/config/config.neon file and add following to services and parameters sections:

   parameters:
   	ldap:
   		hostname: 'xxx.xxx.xxx.xxx'  # your LDAP server ip
   		port: 3268					 # your LDAP server port (if different than default)
   		baseDn: 'DC=domain,DC=local' # your LDAP base DN search - usually change this to your domain.tld
   		loadGroups: true 		     # set to false if you don't want the auto groups loading & roles loading
   
   services:
   	authenticator:
   		class: foglcz\ldap\Authenticator(%ldap%, "yourcompany.com", "yourcomany.local") # Third parameter optional, used if you have different e-mail domains than the AD domain.
   		setup:
   			- addSuccessHandler('id', [@userManager, 'getAuthId'])
   

4. Add following method into your UserManager class:

   /**
    * Success handler for LDAP authenticator - loads the ID in database
    *
    * @param \Toyota\Component\Ldap\Core\Manager $ldap
    * @param array $userData
    * @throws Security\AuthenticationException
    * @return int
    */
   public function getAuthId(\Toyota\Component\Ldap\Core\Manager $ldap, array $userData)
   {
   	$username = 'ldap/' . $userData['username'];
   	if($user = $this->database->table('user')->where('username = ?', $username)->fetch()) {
   		return $user->id;
   	}
   
   	return $this->database->table('user')->insert(array('username' => $username));
   }

   The getAuthId function returns id of the identity, that gets generated - therefore, in rest of your application, you can freely use $user->id for relations etc.

Authentication flow

Essentially, the whole LDAP Authenticator is built on top of callbacks. This means that in most cases, you don't need to extend the class and/or make use of it in your authenticator. Instead, you'd "plug-in" your callbacks to do the work as it's needed in your particular project.

The authentication flow is as follows:

1. $user->login(username, password);

2. Post-process the given username. By default, we strip out the domain parameter (see below) of the constructor, and replace it with FQDN. Therefore, you can have "yourdomain.local" Active Directory forrest, while logging in with the "email@yourdomain.com" usernames - or just with "email" part of the login. See Username generator for more details

3. Connect to LDAP server as specified in the configuration - the library tiesa/ldap is used for this purpose

4. Bind the given username to the domain, effectively authenticating against the LDAP. User is bind in format of username@fqdn , so in your case it might be username@yourdomain.local

5. If no exception is thrown, $userData array is created with following attributes:

   array (2)
   	username => "name.surname@yourdomain.local" (6)
   	fqdn => "yourdomain.local" (14)
   

6. Loop through success handlers. By default this in-loads User Data information from LDAP, and in-loads the groups memberships. Group inheritance is supported, so if user is a part of groupA, which is a part of groupB, both will show up in the memberships.

   Note that here, your registered callbacks are called as well:

   array (8)
   	username => "name.surname@yourdomain.local" (6)
   	fqdn => "yourdomain.local" (14)
   	userinfo => array (10)
   		lastName => "Surname | COMPANY" (17)
   		firstName => "Name" (5)
   		department => "IT" (2)
   		company => "Yourcompany" (15)
   		proxyAddresses => array (2)
   			0 => "SMTP:name.surname@yourcompany.com" (30)
   			1 => "smtp:nsurname@yourdomain.com" (25)
   		fullName => "Name Surname | COMPANY" (23)
   		changePasswordOnLogon => "000000000000000000" (18)
   		UPN => "name.surname@yourdomain.local" (27)
   		mail => "name.surname@yourdomain.com" (25)
   		manager => "CN=Some One,OU=CS,OU=SBSUsers,OU=Users,OU=MyBusiness,DC=yourdomain,DC=local" (85)
   	memberOf => array (16)
   		"CN=DL Decision makers,OU=Distribution Groups,OU=MyBusiness,DC=yourdomain,DC=local" => array (3)
   			dn => "CN=DL Decision makers,OU=Distribution Groups,OU=MyBusiness,DC=yourdomain,DC=local" (82)
   			name => "DL Decision makers" (21)
   			mail => "decisions" (12)
   

7. Check whether the user is in any of the groups that are either allowed or refused to login. Throw exception when user is not allowed to login.

8. Call identity provider and give back the identity returned. For definition, see Identity generator section.

Most of these are built-in, enabled and disabled by altering the configuration (see below.)

Configuration options

Configuration is done within config.neon file. By default, the authenticator is pretty extensible by configuration.

parameters:
	ldap:
		hostname: 'xxx.xxx.xxx.xxx'
		port: 3268
		baseDn: 'DC=yourcompany,DC=com' # Base searchpath within your LDAP
		loadGroups: true            # By default on, turn off if you don't want to load groups
		refuseLogin: ['DL USA']     # Either group FQDN's, names and/or e-mail addresses
		allowLogin:  ['DL VPN']     # Either group FQDN's, names and/or e-mail addresses
		loadRolesAsMailGroups: true # By default off (false/not defined). If on, the group e-mails will be used as roles of the given user
		rolesMap:                   # ldapGroup => roleName array mapping; will take either group FQDN, name and/or e-mail addr.
			VPN_FG: vpn             # If a user is present in such group, the latter value will be used as a user role by identity generator.
			"DL Property": "property"
		adminGroups: ['VPN_FG', 'Administrators'] # add "admin" role if present in the list of roles. Groups can be specified as FQDN's, names and/or e-mail addresses.

Allow / refuse logic

The authenticator employs refuse-first authentication principle. If you define both allow login & refuse login, members of refuse groups will be always refused, regardless of whether they are member of allowed groups.

If you define only refuseLogin parameter, all users will be logged in unless they are member of refused groups.

If you define only allowLogin parameter, all users that are not members of at least one of the allowed groups, will be refused.

Exceptions

Authenticator throws following exceptions:

• class UserInRefuseGroupException extends \foglcz\LDAP\AuthenticationException Thrown when user is a member of refuseLogin groups. Default message is "Members of XXX are not allowed to login."

• class UserNotInAllowedGroupException extends \foglcz\LDAP\AuthenticationException Thrown when you define allowLogin parameter, and the user is not in any of the specified groups. Note that if you also defined refuseLogin groups, this gets thrown only when the user is not a member of those refuse groups (we employ refuse-first policy.) The message is: "You are not member of allowed groups that can login."

• class PossibleConfigurationErrorException extends AuthenticationException Thrown only when you forcefully turn off loadGroups parameter, but still employ functionality, which is dependant on the groups loading. These are allowLogin, refuseLogin, adminGroups, loadRolesAsMailGroups and rolesMap. Note: The exception is not thrown when you turn off groups loading, but set your own memberOf success handler.

• class AuthenticationException extends \Nette\Security\AuthenticationException Thrown when user is, in fact, not allowed to login (the bind against LDAP failed.) Note that we use simple "Username or password is not valid" message.

Note that we throw our AuthenticationException, since we want to make it easy to catch LDAP errors in case you have multiple authenticators like we do.

You can implement try {} catch {} for rewriting the error messages based on context. If you want to catch simply all of them, feel free to catch \Nette\Security\AuthenticationException directly.

Callback options

As you can see from the authentication flow, the LdapAuthenticator is very extensible by default, thanks to callbacks.

The callbacks setup is done via class functions, so that it's easy to configure in config.neon as you can see below:

authenticator:
	class: foglcz\ldap\Authenticator(%ldap%, "comodo.com", "comodo.local")
	setup:
		- setUsernameGenerator([@userModel, 'authGetUsername'])
		- removeSuccessHandler('memberof')
		- addSuccessHandler('memberof', [@userModel, 'getMemberOf'])
		- addSuccessHandler('thumbnail', [\foglcz\LDAP\Success\ThumbnailLoader, 'getThumbnail'])
		- setIdentityGenerator([@userModel, 'authGenerateIdentity'])

Success handlers

Success handlers are used to in-load more information to the $userData array. The userData is then used within Identity generator, as a third parameter of generated identity.

Default success handler is described in top section and returns data, which will be saved within $userData under specified key. Registration function takes two parameters:

1. Key under which to store function result
2. Callback which is called with parameters Manager and $userData.

The success handlers constains no magic, and can be used for effectively anything you want.

Identity generator

The identity generator is used to generate an \Nette\Security\Identity class from the given $userData, which can be extended by SuccessHandlers as seen above. The default identity generator looks up presence of $userData['memberOf'] parameter, to in-load the roles. The default identity generator also appends admin role if user is present within admin groups as defined in config.

Piece of sourcecode is worth a thousand words. Default identity generator looks like this:

public function createIdentity(Toyota\Component\Ldap\Core\Manager $ldap, array $userData)
{
	$roles = array();
	if(!isset($userData['memberOf'])) {
		throw new PossibleConfigurationErrorException('User\'s memberOf index is not set; maybe reset default groups handler?');
	}

	// Load roles based on membership if needed
	if(isset($this->config['loadRolesAsMailGroups'])) {
		$roles = array_merge($roles, $this->loadRoleMailsFromGroups($userData));
	}

	// Load roles mapping if set
	if(isset($this->config['rolesMap'])) {
		$roles = array_merge($roles, $this->loadRoleMapping($userData));
	}

	// In-load admin groups if requested
	if(isset($this->config['adminGroups']) && !in_array('admin', $roles) && $this->loadIsAdminMember($userData)) {
		$roles[] = 'admin';
	}

	// Create identity & return
	return new Identity(isset($userData['id']) ? $userData['id'] : $userData['username'], $roles, $userData);
}

Username generator

The username generator takes any user-supplied input and transforms it into LDAP-valid username. In general, we have two scenarios which we can find in the wild:

1. The AD Forrest name is same as user e-mail domain (forrest name is yourcompany.com)
2. The AD Forrest name is different than user e-mail domain (forrest name is yourcompany.local)

There are also multiple ways how you can authenticate against LDAP:

1. Using the NT-format domain\username
2. Using the post-2000 FQDN format username@domain.tld (that would be the forrest name, like yourdomain.local)

The authenticator employs second option - authentication with full FQDN - by default. This is also the reason for two parameters in the constructor:

class: foglcz\ldap\Authenticator(%ldap%, "<e-mail domain>", "<ldap domain>")

Default username generator works as follows:

• Check whether the user has supplied full e-mail -- checked against the second constructor
• If the user has indeed supplied the e-mail, remove the @domain.com part
• Append the @domain.local if it has been supplied to the constructor.

Subsequent success handlers are using following query string to search for the user:

(|(userprincipalname=:upn:)(sAMAccountName=:username:))

That means, the success handlers search either for plain pre-2000 username or the user's UPN (which is the username@domain.local format). This has some interesting implications, as seen below.

Generator common usage

The default common usage of username generator would be to post-process given username into any format you'd like. For example, you'd like your people to use the default NT-format - thus returning the user supplied username by default.

OR you would like to use the pre-2000 usernames as login usernames, but not using the FQDN parts. For both, you can freely define any logic you want to, in username generator:

public function createUsername(Manager $ldap, $username)
{
	return 'yourdomain\\' . $username;
}

In order to use this generator, following should be added to setup part within config.neon:

authenticator:
	class: foglcz\ldap\Authenticator(%ldap%, "whatever")
	setup:
		- setUsernameGenerator([@userModel, 'createUsername'])

Implications of the username generator rewrite

Default success handlers are using lookup via UPN or pre-2000 account name. This means, that the default success handlers will strip-off any domain\ and @upn.local parts of the given username.

Extend with your class

There is little need to extend the default authenticator by yours, but thats entirely possible. You just need to remember, that in config.neon services: section you can have only one Authenticator - that means that if you extend the \foglcz\LDAP\Authenticator, you also need to remove it from your project's config.neon.

Contribute

Licensed under MIT license. Full text of license available in LICENSE.md file.

Feel free to fork! I grant write access to the repository to pull requests authors, if their changes makes sense for the project. I believe that with this approach, we can make sure that the pull request is highest quality, since it's always merged by the author of the pull request - not by the author of repository. Note: the repository write access is not revoked after merge.

Originally created by Pavel @foglcz Ptacek, (c) 2014

Full list of contributors can be seen in CONTRIBUTORS.md file.