<?php
/**
 * Name: LDAP Authenticate
 * Description: Authenticate a user against an LDAP directory
 * Version: 1.1
 * Author: Mike Macgirvin <http://macgirvin.com/profile/mike>
 * Author: aymhce
 */
 
/**
 * Friendica addon
 * 
 * Module: LDAP Authenticate
 *
 * Authenticate a user against an LDAP directory
 * Useful for Windows Active Directory and other LDAP-based organisations
 * to maintain a single password across the organisation.
 *
 * Optionally authenticates only if a member of a given group in the directory.
 *
 * By default, the person must have registered with Friendica using the normal registration 
 * procedures in order to have a Friendica user record, contact, and profile.
 * However, it's possible with an option to automate the creation of a Friendica basic account.
 *
 * Note when using with Windows Active Directory: you may need to set TLS_CACERT in your site
 * ldap.conf file to the signing cert for your LDAP server. 
 * 
 * The configuration options for this module may be set in the .htconfig.php file
 * e.g.:
 *
 * // ldap hostname server - required
 * $a->config['ldapauth']['ldap_server'] = 'host.example.com';
 * // dn to search users - required
 * $a->config['ldapauth']['ldap_searchdn'] = 'ou=users,dc=example,dc=com';
 * // attribute to find username - required
 * $a->config['ldapauth']['ldap_userattr'] = 'uid';
 *
 * // admin dn - optional - only if ldap server dont have anonymous access
 * $a->config['ldapauth']['ldap_binddn'] = 'cn=admin,dc=example,dc=com';
 * // admin password - optional - only if ldap server dont have anonymous access
 * $a->config['ldapauth']['ldap_bindpw'] = 'password';
 *
 * // for create Friendica account if user exist in ldap
 * //     required an email and a simple (beautiful) nickname on user ldap object
 * //   active account creation - optional - default none
 * $a->config['ldapauth']['ldap_autocreateaccount'] = 'true';
 * //   attribute to get email - optional - default : 'mail'
 * $a->config['ldapauth']['ldap_autocreateaccount_emailattribute'] = 'mail';
 * //   attribute to get nickname - optional - default : 'givenName'
 * $a->config['ldapauth']['ldap_autocreateaccount_nameattribute'] = 'cn';
 *
 * ...etc.
 */
use Friendica\Core\Addon;
use Friendica\Core\Config;
use Friendica\Model\User;

function ldapauth_install()
{
	Addon::registerHook('authenticate', 'addon/ldapauth/ldapauth.php', 'ldapauth_hook_authenticate');
}

function ldapauth_uninstall()
{
	Addon::unregisterHook('authenticate', 'addon/ldapauth/ldapauth.php', 'ldapauth_hook_authenticate');
}


function ldapauth_hook_authenticate($a,&$b) {
    if(ldapauth_authenticate($b['username'],$b['password'])) {
    	$results = get_existing_account($b['username']);
    	if(! empty($results)){
            $b['user_record'] = $results[0];
            $b['authenticated'] = 1;
    	}
    }
    return;
}

function ldapauth_authenticate($username,$password) {

    $ldap_server   = get_config('ldapauth','ldap_server');
    $ldap_binddn   = get_config('ldapauth','ldap_binddn');
    $ldap_bindpw   = get_config('ldapauth','ldap_bindpw');
    $ldap_searchdn = get_config('ldapauth','ldap_searchdn');
    $ldap_userattr = get_config('ldapauth','ldap_userattr');
    $ldap_group    = get_config('ldapauth','ldap_group');
    $ldap_autocreateaccount = get_config('ldapauth','ldap_autocreateaccount');
    $ldap_autocreateaccount_emailattribute = get_config('ldapauth','ldap_autocreateaccount_emailattribute');
    $ldap_autocreateaccount_nameattribute = get_config('ldapauth','ldap_autocreateaccount_nameattribute');
	
    if(! ((strlen($password))
            && (function_exists('ldap_connect'))
            && (strlen($ldap_server)))) {
            logger("ldapauth: not configured or missing php-ldap module");
            return false;
    }

    $connect = @ldap_connect($ldap_server);

    if($connect === false) {
        logger("ldapauth: could not connect to $ldap_server");
        return false;
    }

    @ldap_set_option($connect, LDAP_OPT_PROTOCOL_VERSION,3);
    @ldap_set_option($connect, LDAP_OPT_REFERRALS, 0);
    if((@ldap_bind($connect,$ldap_binddn,$ldap_bindpw)) === false) {
        logger("ldapauth: could not bind $ldap_server as $ldap_binddn");
        return false;
    }

    $res = @ldap_search($connect,$ldap_searchdn, $ldap_userattr . '=' . $username);

    if(! $res) {
        logger("ldapauth: $ldap_userattr=$username,$ldap_searchdn not found");
        return false;
    }

    $id = @ldap_first_entry($connect,$res);

    if(! $id) {
        return false;
    }

    $dn = @ldap_get_dn($connect,$id);

    if(! @ldap_bind($connect,$dn,$password))
        return false;
    
    $emailarray = [];
    $namearray = [];
    if($ldap_autocreateaccount == "true"){
        if(! strlen($ldap_autocreateaccount_emailattribute))
            $ldap_autocreateaccount_emailattribute = "mail";
        if(! strlen($ldap_autocreateaccount_nameattribute))
            $ldap_autocreateaccount_nameattribute = "givenName";
    	$emailarray = @ldap_get_values($connect, $id, $ldap_autocreateaccount_emailattribute);
    	$namearray = @ldap_get_values($connect, $id, $ldap_autocreateaccount_nameattribute);
    }

    if(! strlen($ldap_group)){
    	ldap_autocreateaccount($ldap_autocreateaccount,$username,$password,$emailarray[0],$namearray[0]);
        return true;
    }

    $r = @ldap_compare($connect,$ldap_group,'member',$dn);
    if ($r === -1) {
        $err = @ldap_error($connect);
        $eno = @ldap_errno($connect);
        @ldap_close($connect);

        if ($eno === 32) {
            logger("ldapauth: access control group Does Not Exist");
            return false;
        }
        elseif ($eno === 16) {
            logger('ldapauth: membership attribute does not exist in access control group');
            return false;
        }
        else {
            logger('ldapauth: error: ' . $err);
            return false;
        }
    }
    elseif ($r === false) {
        @ldap_close($connect);
        return false;
    }

    ldap_autocreateaccount($ldap_autocreateaccount,$username,$password,$emailarray[0],$namearray[0]);
    return true;
}

function ldap_autocreateaccount($ldap_autocreateaccount,$username,$password,$email,$name) {
    if($ldap_autocreateaccount == "true"){
        $results = get_existing_account($username);
        if(empty($results)){
            if (strlen($email) > 0 && strlen($name) > 0){
                $arr = array('username'=>$name,'nickname'=>$username,'email'=>$email,'password'=>$password,'verified'=>1);
                $result = create_user($arr);
                if ($result['success']){
                    logger("ldapauth: account " . $username . " created");
                }else{
                    logger("ldapauth: account " . $username . " was not created ! : " . implode($result));
                }
            }else{
                logger("ldapauth: unable to create account, no email or nickname found");
            }
        }
    }
}

function get_existing_account($username){
    return q("SELECT * FROM `user` WHERE `nickname` = '%s' AND `blocked` = 0 AND `verified` = 1 LIMIT 1",$username);
}