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   1  <?php
   2  
   3  /**
   4   * ldaplib.php - LDAP functions & data library
   5   *
   6   * Library file of miscellaneous general-purpose LDAP functions and
   7   * data structures, useful for both ldap authentication (or ldap based
   8   * authentication like CAS) and enrolment plugins.
   9   *
  10   * @author     Iñaki Arenaza
  11   * @package    core
  12   * @subpackage lib
  13   * @copyright  1999 onwards Martin Dougiamas  http://dougiamas.com
  14   * @copyright  2010 onwards Iñaki Arenaza
  15   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  16   */
  17  
  18  defined('MOODLE_INTERNAL') || die();
  19  
  20  // rootDSE is defined as the root of the directory data tree on a directory server.
  21  if (!defined('ROOTDSE')) {
  22      define ('ROOTDSE', '');
  23  }
  24  
  25  // Default page size when using LDAP paged results
  26  if (!defined('LDAP_DEFAULT_PAGESIZE')) {
  27      define('LDAP_DEFAULT_PAGESIZE', 250);
  28  }
  29  
  30  /**
  31   * Returns predefined user types
  32   *
  33   * @return array of predefined user types
  34   */
  35  function ldap_supported_usertypes() {
  36      $types = array();
  37      $types['edir'] = 'Novell Edirectory';
  38      $types['rfc2307'] = 'posixAccount (rfc2307)';
  39      $types['rfc2307bis'] = 'posixAccount (rfc2307bis)';
  40      $types['samba'] = 'sambaSamAccount (v.3.0.7)';
  41      $types['ad'] = 'MS ActiveDirectory';
  42      $types['default'] = get_string('default');
  43      return $types;
  44  }
  45  
  46  /**
  47   * Initializes needed variables for ldap-module
  48   *
  49   * Uses names defined in ldap_supported_usertypes.
  50   * $default is first defined as:
  51   * $default['pseudoname'] = array(
  52   *                      'typename1' => 'value',
  53   *                      'typename2' => 'value'
  54   *                      ....
  55   *                      );
  56   *
  57   * @return array of default values
  58   */
  59  function ldap_getdefaults() {
  60      // All the values have to be written in lowercase, even if the
  61      // standard LDAP attributes are mixed-case
  62      $default['objectclass'] = array(
  63                          'edir' => 'user',
  64                          'rfc2307' => 'posixaccount',
  65                          'rfc2307bis' => 'posixaccount',
  66                          'samba' => 'sambasamaccount',
  67                          'ad' => '(samaccounttype=805306368)',
  68                          'default' => '*'
  69                          );
  70      $default['user_attribute'] = array(
  71                          'edir' => 'cn',
  72                          'rfc2307' => 'uid',
  73                          'rfc2307bis' => 'uid',
  74                          'samba' => 'uid',
  75                          'ad' => 'cn',
  76                          'default' => 'cn'
  77                          );
  78      $default['suspended_attribute'] = array(
  79                          'edir' => '',
  80                          'rfc2307' => '',
  81                          'rfc2307bis' => '',
  82                          'samba' => '',
  83                          'ad' => '',
  84                          'default' => ''
  85                          );
  86      $default['memberattribute'] = array(
  87                          'edir' => 'member',
  88                          'rfc2307' => 'member',
  89                          'rfc2307bis' => 'member',
  90                          'samba' => 'member',
  91                          'ad' => 'member',
  92                          'default' => 'member'
  93                          );
  94      $default['memberattribute_isdn'] = array(
  95                          'edir' => '1',
  96                          'rfc2307' => '0',
  97                          'rfc2307bis' => '1',
  98                          'samba' => '0', // is this right?
  99                          'ad' => '1',
 100                          'default' => '0'
 101                          );
 102      $default['expireattr'] = array (
 103                          'edir' => 'passwordexpirationtime',
 104                          'rfc2307' => 'shadowexpire',
 105                          'rfc2307bis' => 'shadowexpire',
 106                          'samba' => '', // No support yet
 107                          'ad' => 'pwdlastset',
 108                          'default' => ''
 109                          );
 110      return $default;
 111  }
 112  
 113  /**
 114   * Checks if user belongs to specific group(s) or is in a subtree.
 115   *
 116   * Returns true if user belongs to a group in grupdns string OR if the
 117   * DN of the user is in a subtree of the DN provided as "group"
 118   *
 119   * @param mixed $ldapconnection A valid LDAP connection.
 120   * @param string $userid LDAP user id (dn/cn/uid/...) to test membership for.
 121   * @param array $group_dns arrary of group dn
 122   * @param string $member_attrib the name of the membership attribute.
 123   * @return boolean
 124   *
 125   */
 126  function ldap_isgroupmember($ldapconnection, $userid, $group_dns, $member_attrib) {
 127      if (empty($ldapconnection) || empty($userid) || empty($group_dns) || empty($member_attrib)) {
 128          return false;
 129      }
 130  
 131      $result = false;
 132      foreach ($group_dns as $group) {
 133          $group = trim($group);
 134          if (empty($group)) {
 135              continue;
 136          }
 137  
 138          // Check cheaply if the user's DN sits in a subtree of the
 139          // "group" DN provided. Granted, this isn't a proper LDAP
 140          // group, but it's a popular usage.
 141          if (stripos(strrev(strtolower($userid)), strrev(strtolower($group))) === 0) {
 142              $result = true;
 143              break;
 144          }
 145  
 146          $search = ldap_read($ldapconnection, $group,
 147                              '('.$member_attrib.'='.ldap_filter_addslashes($userid).')',
 148                              array($member_attrib));
 149  
 150          if (!empty($search) && ldap_count_entries($ldapconnection, $search)) {
 151              $info = ldap_get_entries_moodle($ldapconnection, $search);
 152              if (count($info) > 0 ) {
 153                  // User is member of group
 154                  $result = true;
 155                  break;
 156              }
 157          }
 158      }
 159  
 160      return $result;
 161  }
 162  
 163  /**
 164   * Tries connect to specified ldap servers. Returns a valid LDAP
 165   * connection or false.
 166   *
 167   * @param string $host_url
 168   * @param integer $ldap_version either 2 (LDAPv2) or 3 (LDAPv3).
 169   * @param string $user_type the configured user type for this connection.
 170   * @param string $bind_dn the binding user dn. If an emtpy string, anonymous binding is used.
 171   * @param string $bind_pw the password for the binding user. Ignored for anonymous bindings.
 172   * @param boolean $opt_deref whether to set LDAP_OPT_DEREF on this connection or not.
 173   * @param string &$debuginfo the debugging information in case the connection fails.
 174   * @param boolean $start_tls whether to use LDAP with TLS (not to be confused with LDAP+SSL)
 175   * @return mixed connection result or false.
 176   */
 177  function ldap_connect_moodle($host_url, $ldap_version, $user_type, $bind_dn, $bind_pw, $opt_deref, &$debuginfo, $start_tls=false) {
 178      if (empty($host_url) || empty($ldap_version) || empty($user_type)) {
 179          $debuginfo = 'No LDAP Host URL, Version or User Type specified in your LDAP settings';
 180          return false;
 181      }
 182  
 183      $debuginfo = '';
 184      $urls = explode(';', $host_url);
 185      foreach ($urls as $server) {
 186          $server = trim($server);
 187          if (empty($server)) {
 188              continue;
 189          }
 190  
 191          $connresult = ldap_connect($server); // ldap_connect returns ALWAYS true
 192  
 193          if (!empty($ldap_version)) {
 194              ldap_set_option($connresult, LDAP_OPT_PROTOCOL_VERSION, $ldap_version);
 195          }
 196  
 197          // Fix MDL-10921
 198          if ($user_type === 'ad') {
 199              ldap_set_option($connresult, LDAP_OPT_REFERRALS, 0);
 200          }
 201  
 202          if (!empty($opt_deref)) {
 203              ldap_set_option($connresult, LDAP_OPT_DEREF, $opt_deref);
 204          }
 205  
 206          if ($start_tls && (!ldap_start_tls($connresult))) {
 207              $debuginfo .= "Server: '$server', Connection: '$connresult', STARTTLS failed.\n";
 208              continue;
 209          }
 210  
 211          if (!empty($bind_dn)) {
 212              $bindresult = @ldap_bind($connresult, $bind_dn, $bind_pw);
 213          } else {
 214              // Bind anonymously
 215              $bindresult = @ldap_bind($connresult);
 216          }
 217  
 218          if ($bindresult) {
 219              return $connresult;
 220          }
 221  
 222          $debuginfo .= "Server: '$server', Connection: '$connresult', Bind result: '$bindresult'\n";
 223      }
 224  
 225      // If any of servers were alive we have already returned connection.
 226      return false;
 227  }
 228  
 229  /**
 230   * Search specified contexts for username and return the user dn like:
 231   * cn=username,ou=suborg,o=org
 232   *
 233   * @param mixed $ldapconnection a valid LDAP connection.
 234   * @param mixed $username username (external LDAP encoding, no db slashes).
 235   * @param array $contexts contexts to look for the user.
 236   * @param string $objectclass objectlass of the user (in LDAP filter syntax).
 237   * @param string $search_attrib the attribute use to look for the user.
 238   * @param boolean $search_sub whether to search subcontexts or not.
 239   * @return mixed the user dn (external LDAP encoding, no db slashes) or false
 240   *
 241   */
 242  function ldap_find_userdn($ldapconnection, $username, $contexts, $objectclass, $search_attrib, $search_sub) {
 243      if (empty($ldapconnection) || empty($username) || empty($contexts) || empty($objectclass) || empty($search_attrib)) {
 244          return false;
 245      }
 246  
 247      // Default return value
 248      $ldap_user_dn = false;
 249  
 250      // Get all contexts and look for first matching user
 251      foreach ($contexts as $context) {
 252          $context = trim($context);
 253          if (empty($context)) {
 254              continue;
 255          }
 256  
 257          if ($search_sub) {
 258              $ldap_result = @ldap_search($ldapconnection, $context,
 259                                          '(&'.$objectclass.'('.$search_attrib.'='.ldap_filter_addslashes($username).'))',
 260                                          array($search_attrib));
 261          } else {
 262              $ldap_result = @ldap_list($ldapconnection, $context,
 263                                        '(&'.$objectclass.'('.$search_attrib.'='.ldap_filter_addslashes($username).'))',
 264                                        array($search_attrib));
 265          }
 266  
 267          if (!$ldap_result) {
 268              continue; // Not found in this context.
 269          }
 270  
 271          $entry = ldap_first_entry($ldapconnection, $ldap_result);
 272          if ($entry) {
 273              $ldap_user_dn = ldap_get_dn($ldapconnection, $entry);
 274              break;
 275          }
 276      }
 277  
 278      return $ldap_user_dn;
 279  }
 280  
 281  /**
 282   * Normalise the supplied objectclass filter.
 283   *
 284   * This normalisation is a rudimentary attempt to format the objectclass filter correctly.
 285   *
 286   * @param string $objectclass The objectclass to normalise
 287   * @param string $default The default objectclass value to use if no objectclass was supplied
 288   * @return string The normalised objectclass.
 289   */
 290  function ldap_normalise_objectclass($objectclass, $default = '*') {
 291      if (empty($objectclass)) {
 292          // Can't send empty filter.
 293          $return = sprintf('(objectClass=%s)', $default);
 294      } else if (stripos($objectclass, 'objectClass=') === 0) {
 295          // Value is 'objectClass=some-string-here', so just add () around the value (filter _must_ have them).
 296          $return = sprintf('(%s)', $objectclass);
 297      } else if (stripos($objectclass, '(') !== 0) {
 298          // Value is 'some-string-not-starting-with-left-parentheses', which is assumed to be the objectClass matching value.
 299          // Build a valid filter using the value it.
 300          $return = sprintf('(objectClass=%s)', $objectclass);
 301      } else {
 302          // There is an additional possible value '(some-string-here)', that can be used to specify any valid filter
 303          // string, to select subsets of users based on any criteria.
 304          //
 305          // For example, we could select the users whose objectClass is 'user' and have the 'enabledMoodleUser'
 306          // attribute, with something like:
 307          //
 308          // (&(objectClass=user)(enabledMoodleUser=1))
 309          //
 310          // In this particular case we don't need to do anything, so leave $this->config->objectclass as is.
 311          $return = $objectclass;
 312      }
 313  
 314      return $return;
 315  }
 316  
 317  /**
 318   * Returns values like ldap_get_entries but is binary compatible and
 319   * returns all attributes as array.
 320   *
 321   * @param mixed $ldapconnection A valid LDAP connection
 322   * @param mixed $searchresult A search result from ldap_search, ldap_list, etc.
 323   * @return array ldap-entries with lower-cased attributes as indexes
 324   */
 325  function ldap_get_entries_moodle($ldapconnection, $searchresult) {
 326      if (empty($ldapconnection) || empty($searchresult)) {
 327          return array();
 328      }
 329  
 330      $i = 0;
 331      $result = array();
 332      $entry = ldap_first_entry($ldapconnection, $searchresult);
 333      if (!$entry) {
 334          return array();
 335      }
 336      do {
 337          $attributes = array_change_key_case(ldap_get_attributes($ldapconnection, $entry), CASE_LOWER);
 338          for ($j = 0; $j < $attributes['count']; $j++) {
 339              $values = ldap_get_values_len($ldapconnection, $entry, $attributes[$j]);
 340              if (is_array($values)) {
 341                  $result[$i][$attributes[$j]] = $values;
 342              } else {
 343                  $result[$i][$attributes[$j]] = array($values);
 344              }
 345          }
 346          $i++;
 347      } while ($entry = ldap_next_entry($ldapconnection, $entry));
 348  
 349      return ($result);
 350  }
 351  
 352  /**
 353   * Quote control characters in texts used in LDAP filters - see RFC 4515/2254
 354   *
 355   * @param string filter string to quote
 356   * @return string the filter string quoted
 357   */
 358  function ldap_filter_addslashes($text) {
 359      $text = str_replace('\\', '\\5c', $text);
 360      $text = str_replace(array('*',    '(',    ')',    "\0"),
 361                          array('\\2a', '\\28', '\\29', '\\00'), $text);
 362      return $text;
 363  }
 364  
 365  if(!defined('LDAP_DN_SPECIAL_CHARS')) {
 366      define('LDAP_DN_SPECIAL_CHARS', 0);
 367  }
 368  if(!defined('LDAP_DN_SPECIAL_CHARS_QUOTED_NUM')) {
 369      define('LDAP_DN_SPECIAL_CHARS_QUOTED_NUM', 1);
 370  }
 371  if(!defined('LDAP_DN_SPECIAL_CHARS_QUOTED_ALPHA')) {
 372      define('LDAP_DN_SPECIAL_CHARS_QUOTED_ALPHA', 2);
 373  }
 374  if(!defined('LDAP_DN_SPECIAL_CHARS_QUOTED_ALPHA_REGEX')) {
 375      define('LDAP_DN_SPECIAL_CHARS_QUOTED_ALPHA_REGEX', 3);
 376  }
 377  
 378  /**
 379   * The order of the special characters in these arrays _IS IMPORTANT_.
 380   * Make sure '\\5C' (and '\\') are the first elements of the arrays.
 381   * Otherwise we'll double replace '\' with '\5C' which is Bad(tm)
 382   */
 383  function ldap_get_dn_special_chars() {
 384      static $specialchars = null;
 385  
 386      if ($specialchars !== null) {
 387          return $specialchars;
 388      }
 389  
 390      $specialchars = array (
 391          LDAP_DN_SPECIAL_CHARS              => array('\\',  ' ',   '"',   '#',   '+',   ',',   ';',   '<',   '=',   '>',   "\0"),
 392          LDAP_DN_SPECIAL_CHARS_QUOTED_NUM   => array('\\5c','\\20','\\22','\\23','\\2b','\\2c','\\3b','\\3c','\\3d','\\3e','\\00'),
 393          LDAP_DN_SPECIAL_CHARS_QUOTED_ALPHA => array('\\\\','\\ ', '\\"', '\\#', '\\+', '\\,', '\\;', '\\<', '\\=', '\\>', '\\00'),
 394          );
 395      $alpharegex = implode('|', array_map (function ($expr) { return preg_quote($expr); },
 396                                            $specialchars[LDAP_DN_SPECIAL_CHARS_QUOTED_ALPHA]));
 397      $specialchars[LDAP_DN_SPECIAL_CHARS_QUOTED_ALPHA_REGEX] = $alpharegex;
 398  
 399      return $specialchars;
 400  }
 401  
 402  /**
 403   * Quote control characters in AttributeValue parts of a RelativeDistinguishedName
 404   * used in LDAP distinguished names - See RFC 4514/2253
 405   *
 406   * @param string the AttributeValue to quote
 407   * @return string the AttributeValue quoted
 408   */
 409  function ldap_addslashes($text) {
 410      $special_dn_chars = ldap_get_dn_special_chars();
 411  
 412      // Use the preferred/universal quotation method: ESC HEX HEX
 413      // (i.e., the 'numerically' quoted characters)
 414      $text = str_replace ($special_dn_chars[LDAP_DN_SPECIAL_CHARS],
 415                           $special_dn_chars[LDAP_DN_SPECIAL_CHARS_QUOTED_NUM],
 416                           $text);
 417      return $text;
 418  }
 419  
 420  /**
 421   * Unquote control characters in AttributeValue parts of a RelativeDistinguishedName
 422   * used in LDAP distinguished names - See RFC 4514/2253
 423   *
 424   * @param string the AttributeValue quoted
 425   * @return string the AttributeValue unquoted
 426   */
 427  function ldap_stripslashes($text) {
 428      $specialchars = ldap_get_dn_special_chars();
 429  
 430      // We can't unquote in two steps, as we end up unquoting too much in certain cases. So
 431      // we need to build a regexp containing both the 'numerically' and 'alphabetically'
 432      // quoted characters. We don't use LDAP_DN_SPECIAL_CHARS_QUOTED_NUM because the
 433      // standard allows us to quote any character with this encoding, not just the special
 434      // ones.
 435      // @TODO: This still misses some special (and rarely used) cases, but we need
 436      // a full state machine to handle them.
 437      $quoted = '/(\\\\[0-9A-Fa-f]{2}|' . $specialchars[LDAP_DN_SPECIAL_CHARS_QUOTED_ALPHA_REGEX] . ')/';
 438      $text = preg_replace_callback($quoted,
 439                                    function ($match) use ($specialchars) {
 440                                        if (ctype_xdigit(ltrim($match[1], '\\'))) {
 441                                            return chr(hexdec($match[1]));
 442                                        } else {
 443                                            return str_replace($specialchars[LDAP_DN_SPECIAL_CHARS_QUOTED_ALPHA],
 444                                                               $specialchars[LDAP_DN_SPECIAL_CHARS],
 445                                                               $match[1]);
 446                                        }
 447                                    },
 448                                    $text);
 449  
 450      return $text;
 451  }
 452  
 453  
 454  /**
 455   * Check if we use LDAP version 3, otherwise the server cannot use them.
 456   *
 457   * @param ldapversion integer The LDAP protocol version we use.
 458   *
 459   * @return boolean true is paged results can be used, false otherwise.
 460   */
 461  function ldap_paged_results_supported($ldapversion) {
 462      if ((int)$ldapversion === 3) {
 463          return true;
 464      }
 465  
 466      return false;
 467  }