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  • Bug fixes for general core bugs in 3.11.x will end 14 Nov 2022 (12 months plus 6 months extension).
  • Bug fixes for security issues in 3.11.x will end 13 Nov 2023 (18 months plus 12 months extension).
  • PHP version: minimum PHP 7.3.0 Note: minimum PHP version has increased since Moodle 3.10. PHP 7.4.x is supported too.
/lib/ -> ldaplib.php (source)
   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  // Paged results control OID value.
  26  if (!defined('LDAP_PAGED_RESULTS_CONTROL')) {
  27      define ('LDAP_PAGED_RESULTS_CONTROL', '1.2.840.113556.1.4.319');
  28  }
  29  
  30  // Default page size when using LDAP paged results
  31  if (!defined('LDAP_DEFAULT_PAGESIZE')) {
  32      define('LDAP_DEFAULT_PAGESIZE', 250);
  33  }
  34  
  35  /**
  36   * Returns predefined user types
  37   *
  38   * @return array of predefined user types
  39   */
  40  function ldap_supported_usertypes() {
  41      $types = array();
  42      $types['edir'] = 'Novell Edirectory';
  43      $types['rfc2307'] = 'posixAccount (rfc2307)';
  44      $types['rfc2307bis'] = 'posixAccount (rfc2307bis)';
  45      $types['samba'] = 'sambaSamAccount (v.3.0.7)';
  46      $types['ad'] = 'MS ActiveDirectory';
  47      $types['default'] = get_string('default');
  48      return $types;
  49  }
  50  
  51  /**
  52   * Initializes needed variables for ldap-module
  53   *
  54   * Uses names defined in ldap_supported_usertypes.
  55   * $default is first defined as:
  56   * $default['pseudoname'] = array(
  57   *                      'typename1' => 'value',
  58   *                      'typename2' => 'value'
  59   *                      ....
  60   *                      );
  61   *
  62   * @return array of default values
  63   */
  64  function ldap_getdefaults() {
  65      // All the values have to be written in lowercase, even if the
  66      // standard LDAP attributes are mixed-case
  67      $default['objectclass'] = array(
  68                          'edir' => 'user',
  69                          'rfc2307' => 'posixaccount',
  70                          'rfc2307bis' => 'posixaccount',
  71                          'samba' => 'sambasamaccount',
  72                          'ad' => '(samaccounttype=805306368)',
  73                          'default' => '*'
  74                          );
  75      $default['user_attribute'] = array(
  76                          'edir' => 'cn',
  77                          'rfc2307' => 'uid',
  78                          'rfc2307bis' => 'uid',
  79                          'samba' => 'uid',
  80                          'ad' => 'cn',
  81                          'default' => 'cn'
  82                          );
  83      $default['suspended_attribute'] = array(
  84                          'edir' => '',
  85                          'rfc2307' => '',
  86                          'rfc2307bis' => '',
  87                          'samba' => '',
  88                          'ad' => '',
  89                          'default' => ''
  90                          );
  91      $default['memberattribute'] = array(
  92                          'edir' => 'member',
  93                          'rfc2307' => 'member',
  94                          'rfc2307bis' => 'member',
  95                          'samba' => 'member',
  96                          'ad' => 'member',
  97                          'default' => 'member'
  98                          );
  99      $default['memberattribute_isdn'] = array(
 100                          'edir' => '1',
 101                          'rfc2307' => '0',
 102                          'rfc2307bis' => '1',
 103                          'samba' => '0', // is this right?
 104                          'ad' => '1',
 105                          'default' => '0'
 106                          );
 107      $default['expireattr'] = array (
 108                          'edir' => 'passwordexpirationtime',
 109                          'rfc2307' => 'shadowexpire',
 110                          'rfc2307bis' => 'shadowexpire',
 111                          'samba' => '', // No support yet
 112                          'ad' => 'pwdlastset',
 113                          'default' => ''
 114                          );
 115      return $default;
 116  }
 117  
 118  /**
 119   * Checks if user belongs to specific group(s) or is in a subtree.
 120   *
 121   * Returns true if user belongs to a group in grupdns string OR if the
 122   * DN of the user is in a subtree of the DN provided as "group"
 123   *
 124   * @param mixed $ldapconnection A valid LDAP connection.
 125   * @param string $userid LDAP user id (dn/cn/uid/...) to test membership for.
 126   * @param array $group_dns arrary of group dn
 127   * @param string $member_attrib the name of the membership attribute.
 128   * @return boolean
 129   *
 130   */
 131  function ldap_isgroupmember($ldapconnection, $userid, $group_dns, $member_attrib) {
 132      if (empty($ldapconnection) || empty($userid) || empty($group_dns) || empty($member_attrib)) {
 133          return false;
 134      }
 135  
 136      $result = false;
 137      foreach ($group_dns as $group) {
 138          $group = trim($group);
 139          if (empty($group)) {
 140              continue;
 141          }
 142  
 143          // Check cheaply if the user's DN sits in a subtree of the
 144          // "group" DN provided. Granted, this isn't a proper LDAP
 145          // group, but it's a popular usage.
 146          if (stripos(strrev(strtolower($userid)), strrev(strtolower($group))) === 0) {
 147              $result = true;
 148              break;
 149          }
 150  
 151          $search = ldap_read($ldapconnection, $group,
 152                              '('.$member_attrib.'='.ldap_filter_addslashes($userid).')',
 153                              array($member_attrib));
 154  
 155          if (!empty($search) && ldap_count_entries($ldapconnection, $search)) {
 156              $info = ldap_get_entries_moodle($ldapconnection, $search);
 157              if (count($info) > 0 ) {
 158                  // User is member of group
 159                  $result = true;
 160                  break;
 161              }
 162          }
 163      }
 164  
 165      return $result;
 166  }
 167  
 168  /**
 169   * Tries connect to specified ldap servers. Returns a valid LDAP
 170   * connection or false.
 171   *
 172   * @param string $host_url
 173   * @param integer $ldap_version either 2 (LDAPv2) or 3 (LDAPv3).
 174   * @param string $user_type the configured user type for this connection.
 175   * @param string $bind_dn the binding user dn. If an emtpy string, anonymous binding is used.
 176   * @param string $bind_pw the password for the binding user. Ignored for anonymous bindings.
 177   * @param boolean $opt_deref whether to set LDAP_OPT_DEREF on this connection or not.
 178   * @param string &$debuginfo the debugging information in case the connection fails.
 179   * @param boolean $start_tls whether to use LDAP with TLS (not to be confused with LDAP+SSL)
 180   * @return mixed connection result or false.
 181   */
 182  function ldap_connect_moodle($host_url, $ldap_version, $user_type, $bind_dn, $bind_pw, $opt_deref, &$debuginfo, $start_tls=false) {
 183      if (empty($host_url) || empty($ldap_version) || empty($user_type)) {
 184          $debuginfo = 'No LDAP Host URL, Version or User Type specified in your LDAP settings';
 185          return false;
 186      }
 187  
 188      $debuginfo = '';
 189      $urls = explode(';', $host_url);
 190      foreach ($urls as $server) {
 191          $server = trim($server);
 192          if (empty($server)) {
 193              continue;
 194          }
 195  
 196          $connresult = ldap_connect($server); // ldap_connect returns ALWAYS true
 197  
 198          if (!empty($ldap_version)) {
 199              ldap_set_option($connresult, LDAP_OPT_PROTOCOL_VERSION, $ldap_version);
 200          }
 201  
 202          // Fix MDL-10921
 203          if ($user_type === 'ad') {
 204              ldap_set_option($connresult, LDAP_OPT_REFERRALS, 0);
 205          }
 206  
 207          if (!empty($opt_deref)) {
 208              ldap_set_option($connresult, LDAP_OPT_DEREF, $opt_deref);
 209          }
 210  
 211          if ($start_tls && (!ldap_start_tls($connresult))) {
 212              $debuginfo .= "Server: '$server', Connection: '$connresult', STARTTLS failed.\n";
 213              continue;
 214          }
 215  
 216          if (!empty($bind_dn)) {
 217              $bindresult = @ldap_bind($connresult, $bind_dn, $bind_pw);
 218          } else {
 219              // Bind anonymously
 220              $bindresult = @ldap_bind($connresult);
 221          }
 222  
 223          if ($bindresult) {
 224              return $connresult;
 225          }
 226  
 227          $debuginfo .= "Server: '$server', Connection: '$connresult', Bind result: '$bindresult'\n";
 228      }
 229  
 230      // If any of servers were alive we have already returned connection.
 231      return false;
 232  }
 233  
 234  /**
 235   * Search specified contexts for username and return the user dn like:
 236   * cn=username,ou=suborg,o=org
 237   *
 238   * @param mixed $ldapconnection a valid LDAP connection.
 239   * @param mixed $username username (external LDAP encoding, no db slashes).
 240   * @param array $contexts contexts to look for the user.
 241   * @param string $objectclass objectlass of the user (in LDAP filter syntax).
 242   * @param string $search_attrib the attribute use to look for the user.
 243   * @param boolean $search_sub whether to search subcontexts or not.
 244   * @return mixed the user dn (external LDAP encoding, no db slashes) or false
 245   *
 246   */
 247  function ldap_find_userdn($ldapconnection, $username, $contexts, $objectclass, $search_attrib, $search_sub) {
 248      if (empty($ldapconnection) || empty($username) || empty($contexts) || empty($objectclass) || empty($search_attrib)) {
 249          return false;
 250      }
 251  
 252      // Default return value
 253      $ldap_user_dn = false;
 254  
 255      // Get all contexts and look for first matching user
 256      foreach ($contexts as $context) {
 257          $context = trim($context);
 258          if (empty($context)) {
 259              continue;
 260          }
 261  
 262          if ($search_sub) {
 263              $ldap_result = @ldap_search($ldapconnection, $context,
 264                                          '(&'.$objectclass.'('.$search_attrib.'='.ldap_filter_addslashes($username).'))',
 265                                          array($search_attrib));
 266          } else {
 267              $ldap_result = @ldap_list($ldapconnection, $context,
 268                                        '(&'.$objectclass.'('.$search_attrib.'='.ldap_filter_addslashes($username).'))',
 269                                        array($search_attrib));
 270          }
 271  
 272          if (!$ldap_result) {
 273              continue; // Not found in this context.
 274          }
 275  
 276          $entry = ldap_first_entry($ldapconnection, $ldap_result);
 277          if ($entry) {
 278              $ldap_user_dn = ldap_get_dn($ldapconnection, $entry);
 279              break;
 280          }
 281      }
 282  
 283      return $ldap_user_dn;
 284  }
 285  
 286  /**
 287   * Normalise the supplied objectclass filter.
 288   *
 289   * This normalisation is a rudimentary attempt to format the objectclass filter correctly.
 290   *
 291   * @param string $objectclass The objectclass to normalise
 292   * @param string $default The default objectclass value to use if no objectclass was supplied
 293   * @return string The normalised objectclass.
 294   */
 295  function ldap_normalise_objectclass($objectclass, $default = '*') {
 296      if (empty($objectclass)) {
 297          // Can't send empty filter.
 298          $return = sprintf('(objectClass=%s)', $default);
 299      } else if (stripos($objectclass, 'objectClass=') === 0) {
 300          // Value is 'objectClass=some-string-here', so just add () around the value (filter _must_ have them).
 301          $return = sprintf('(%s)', $objectclass);
 302      } else if (stripos($objectclass, '(') !== 0) {
 303          // Value is 'some-string-not-starting-with-left-parentheses', which is assumed to be the objectClass matching value.
 304          // Build a valid filter using the value it.
 305          $return = sprintf('(objectClass=%s)', $objectclass);
 306      } else {
 307          // There is an additional possible value '(some-string-here)', that can be used to specify any valid filter
 308          // string, to select subsets of users based on any criteria.
 309          //
 310          // For example, we could select the users whose objectClass is 'user' and have the 'enabledMoodleUser'
 311          // attribute, with something like:
 312          //
 313          // (&(objectClass=user)(enabledMoodleUser=1))
 314          //
 315          // In this particular case we don't need to do anything, so leave $this->config->objectclass as is.
 316          $return = $objectclass;
 317      }
 318  
 319      return $return;
 320  }
 321  
 322  /**
 323   * Returns values like ldap_get_entries but is binary compatible and
 324   * returns all attributes as array.
 325   *
 326   * @param mixed $ldapconnection A valid LDAP connection
 327   * @param mixed $searchresult A search result from ldap_search, ldap_list, etc.
 328   * @return array ldap-entries with lower-cased attributes as indexes
 329   */
 330  function ldap_get_entries_moodle($ldapconnection, $searchresult) {
 331      if (empty($ldapconnection) || empty($searchresult)) {
 332          return array();
 333      }
 334  
 335      $i = 0;
 336      $result = array();
 337      $entry = ldap_first_entry($ldapconnection, $searchresult);
 338      if (!$entry) {
 339          return array();
 340      }
 341      do {
 342          $attributes = array();
 343          $attribute = ldap_first_attribute($ldapconnection, $entry);
 344          while ($attribute !== false) {
 345              $attributes[] = strtolower($attribute); // Attribute names don't usually contain non-ASCII characters.
 346              $attribute = ldap_next_attribute($ldapconnection, $entry);
 347          }
 348          foreach ($attributes as $attribute) {
 349              $values = ldap_get_values_len($ldapconnection, $entry, $attribute);
 350              if (is_array($values)) {
 351                  $result[$i][$attribute] = $values;
 352              } else {
 353                  $result[$i][$attribute] = array($values);
 354              }
 355          }
 356          $i++;
 357      } while ($entry = ldap_next_entry($ldapconnection, $entry));
 358  
 359      return ($result);
 360  }
 361  
 362  /**
 363   * Quote control characters in texts used in LDAP filters - see RFC 4515/2254
 364   *
 365   * @param string filter string to quote
 366   * @return string the filter string quoted
 367   */
 368  function ldap_filter_addslashes($text) {
 369      $text = str_replace('\\', '\\5c', $text);
 370      $text = str_replace(array('*',    '(',    ')',    "\0"),
 371                          array('\\2a', '\\28', '\\29', '\\00'), $text);
 372      return $text;
 373  }
 374  
 375  if(!defined('LDAP_DN_SPECIAL_CHARS')) {
 376      define('LDAP_DN_SPECIAL_CHARS', 0);
 377  }
 378  if(!defined('LDAP_DN_SPECIAL_CHARS_QUOTED_NUM')) {
 379      define('LDAP_DN_SPECIAL_CHARS_QUOTED_NUM', 1);
 380  }
 381  if(!defined('LDAP_DN_SPECIAL_CHARS_QUOTED_ALPHA')) {
 382      define('LDAP_DN_SPECIAL_CHARS_QUOTED_ALPHA', 2);
 383  }
 384  if(!defined('LDAP_DN_SPECIAL_CHARS_QUOTED_ALPHA_REGEX')) {
 385      define('LDAP_DN_SPECIAL_CHARS_QUOTED_ALPHA_REGEX', 3);
 386  }
 387  
 388  /**
 389   * The order of the special characters in these arrays _IS IMPORTANT_.
 390   * Make sure '\\5C' (and '\\') are the first elements of the arrays.
 391   * Otherwise we'll double replace '\' with '\5C' which is Bad(tm)
 392   */
 393  function ldap_get_dn_special_chars() {
 394      static $specialchars = null;
 395  
 396      if ($specialchars !== null) {
 397          return $specialchars;
 398      }
 399  
 400      $specialchars = array (
 401          LDAP_DN_SPECIAL_CHARS              => array('\\',  ' ',   '"',   '#',   '+',   ',',   ';',   '<',   '=',   '>',   "\0"),
 402          LDAP_DN_SPECIAL_CHARS_QUOTED_NUM   => array('\\5c','\\20','\\22','\\23','\\2b','\\2c','\\3b','\\3c','\\3d','\\3e','\\00'),
 403          LDAP_DN_SPECIAL_CHARS_QUOTED_ALPHA => array('\\\\','\\ ', '\\"', '\\#', '\\+', '\\,', '\\;', '\\<', '\\=', '\\>', '\\00'),
 404          );
 405      $alpharegex = implode('|', array_map (function ($expr) { return preg_quote($expr); },
 406                                            $specialchars[LDAP_DN_SPECIAL_CHARS_QUOTED_ALPHA]));
 407      $specialchars[LDAP_DN_SPECIAL_CHARS_QUOTED_ALPHA_REGEX] = $alpharegex;
 408  
 409      return $specialchars;
 410  }
 411  
 412  /**
 413   * Quote control characters in AttributeValue parts of a RelativeDistinguishedName
 414   * used in LDAP distinguished names - See RFC 4514/2253
 415   *
 416   * @param string the AttributeValue to quote
 417   * @return string the AttributeValue quoted
 418   */
 419  function ldap_addslashes($text) {
 420      $special_dn_chars = ldap_get_dn_special_chars();
 421  
 422      // Use the preferred/universal quotation method: ESC HEX HEX
 423      // (i.e., the 'numerically' quoted characters)
 424      $text = str_replace ($special_dn_chars[LDAP_DN_SPECIAL_CHARS],
 425                           $special_dn_chars[LDAP_DN_SPECIAL_CHARS_QUOTED_NUM],
 426                           $text);
 427      return $text;
 428  }
 429  
 430  /**
 431   * Unquote control characters in AttributeValue parts of a RelativeDistinguishedName
 432   * used in LDAP distinguished names - See RFC 4514/2253
 433   *
 434   * @param string the AttributeValue quoted
 435   * @return string the AttributeValue unquoted
 436   */
 437  function ldap_stripslashes($text) {
 438      $specialchars = ldap_get_dn_special_chars();
 439  
 440      // We can't unquote in two steps, as we end up unquoting too much in certain cases. So
 441      // we need to build a regexp containing both the 'numerically' and 'alphabetically'
 442      // quoted characters. We don't use LDAP_DN_SPECIAL_CHARS_QUOTED_NUM because the
 443      // standard allows us to quote any character with this encoding, not just the special
 444      // ones.
 445      // @TODO: This still misses some special (and rarely used) cases, but we need
 446      // a full state machine to handle them.
 447      $quoted = '/(\\\\[0-9A-Fa-f]{2}|' . $specialchars[LDAP_DN_SPECIAL_CHARS_QUOTED_ALPHA_REGEX] . ')/';
 448      $text = preg_replace_callback($quoted,
 449                                    function ($match) use ($specialchars) {
 450                                        if (ctype_xdigit(ltrim($match[1], '\\'))) {
 451                                            return chr(hexdec(ltrim($match[1], '\\')));
 452                                        } else {
 453                                            return str_replace($specialchars[LDAP_DN_SPECIAL_CHARS_QUOTED_ALPHA],
 454                                                               $specialchars[LDAP_DN_SPECIAL_CHARS],
 455                                                               $match[1]);
 456                                        }
 457                                    },
 458                                    $text);
 459  
 460      return $text;
 461  }
 462  
 463  
 464  /**
 465   * Check if we can use paged results (see RFC 2696). We need to use
 466   * LDAP version 3 (or later), otherwise the server cannot use them. If
 467   * we also pass in a valid LDAP connection handle, we also check
 468   * whether the server actually supports them.
 469   *
 470   * @param ldapversion integer The LDAP protocol version we use.
 471   * @param ldapconnection resource An existing LDAP connection (optional).
 472   *
 473   * @return boolean true is paged results can be used, false otherwise.
 474   */
 475  function ldap_paged_results_supported($ldapversion, $ldapconnection = null) {
 476      if ((int)$ldapversion < 3) {
 477          // Minimun required version: LDAP v3.
 478          return false;
 479      }
 480  
 481      if ($ldapconnection === null) {
 482          // Can't verify it, so assume it isn't supported.
 483          return false;
 484      }
 485  
 486      // Connect to the rootDSE and get the supported controls.
 487      $sr = ldap_read($ldapconnection, ROOTDSE, '(objectClass=*)', array('supportedControl'));
 488      if (!$sr) {
 489          return false;
 490      }
 491  
 492      $entries = ldap_get_entries_moodle($ldapconnection, $sr);
 493      if (empty($entries)) {
 494          return false;
 495      }
 496      $info = $entries[0];
 497      if (isset($info['supportedcontrol']) && in_array(LDAP_PAGED_RESULTS_CONTROL, $info['supportedcontrol'])) {
 498          return true;
 499      }
 500  
 501      return false;
 502  }