ldap auth and enrolment: MDL-19672 prevent update_user_record() from mangling distinguished names with backslashes

In addition to it, in order to be able to used a distiguished name with '\'
(and other LDAP special characters) in a LDAP filter to find the user
enrolments, we need to quote it using the LDAP filter quoting rules

auth/ldap/auth.php

@@ -222,7 +222,7 @@ class auth_plugin_ldap extends auth_plugin_base {
             }
             $ldapval = NULL;
             foreach ($values as $value) {
-                if ($value == 'dn') {
+                if ((moodle_strtolower($value) == 'dn') || (moodle_strtolower($value) == 'distinguishedname')) {
                     $result[$key] = $user_dn;
                 }
                 if (!array_key_exists($value, $user_entry[0])) {
@@ -2121,7 +2121,7 @@ class auth_plugin_ldap extends auth_plugin_base {
     }
 
     /**
-     * Quote control characters in texts used in ldap filters - see rfc2254.txt
+     * Quote control characters in texts used in ldap filters - see RFC 4515/2254
      *
      * @param string
      */
@@ -2133,14 +2133,23 @@ class auth_plugin_ldap extends auth_plugin_base {
     }
 
     /**
-     * Quote control characters in quoted "texts" used in ldap
+     * The order of the special characters in these arrays _IS IMPORTANT_.
+     * Make sure '\\5C' (and '\\') are the first elements of the arrays.
+     * Otherwise we'll double replace '\' with '\5C' which is Bad(tm)
+     */ 
+    var $LDAP_DN_QUOTED_SPECIAL_CHARS = array('\\5c','\\20','\\22','\\23','\\2b','\\2c','\\3b','\\3c','\\3d','\\3e','\\00');
+    var $LDAP_DN_SPECIAL_CHARS        = array('\\',  ' ',   '"',   '#',   '+',   ',',   ';',   '<',   '=',   '>',   "\0");
+
+    /**
+     * Quote control characters in distinguished names used in ldap - See RFC 4514/2253
      *
      * @param string
+     * @return string
      */
     function ldap_addslashes($text) {
-        $text = str_replace('\\', '\\\\', $text);
-        $text = str_replace(array('"',   "\0"),
-                            array('\\"', '\\00'), $text);
+        $text = str_replace ($this->LDAP_DN_SPECIAL_CHARS,
+                             $this->LDAP_DN_QUOTED_SPECIAL_CHARS,
+                             $text);
         return $text;
     }
 

enrol/ldap/enrol.php

@@ -501,7 +501,7 @@ function find_ext_enrolments ($ldap_connection, $memberuid, $role){
     }
 
     // define the search pattern
-    $ldap_search_pattern = "(".$CFG->{'enrol_ldap_memberattribute_role'.$role->id}."=".$memberuid.")";
+    $ldap_search_pattern = "(".$CFG->{'enrol_ldap_memberattribute_role'.$role->id}."=".$this->filter_addslashes($memberuid).")";
     if (!empty($CFG->enrol_ldap_objectclass)){ 
         $ldap_search_pattern='(&(objectclass='.$CFG->enrol_ldap_objectclass.')'.$ldap_search_pattern.')';
     }
@@ -671,6 +671,18 @@ function check_legacy_config () {
     }
 }
 
+/**
+ * Quote control characters in texts used in ldap filters - see RFC 4515/2254
+ *
+ * @param string
+ */
+function filter_addslashes($text) {
+    $text = str_replace('\\', '\\5c', $text);
+    $text = str_replace(array('*',    '(',    ')',    "\0"),
+                        array('\\2a', '\\28', '\\29', '\\00'), $text);
+    return $text;
+}
+
 } // end of class
 
 ?>

lib/moodlelib.php

@@ -2975,7 +2975,7 @@ function update_user_record($username, $authplugin) {
                 continue;
             }
             if ($confval === 'onlogin') {
-                $value = addslashes(stripslashes($value));   // Just in case
+                $value = addslashes($value);
                 // MDL-4207 Don't overwrite modified user profile values with
                 // empty LDAP values when 'unlocked if empty' is set. The purpose
                 // of the setting 'unlocked if empty' is to allow the user to fill