MDL-23437 backup - restore security checks
[moodle.git] / backup / util / checks / backup_check.class.php
1 <?php
3 // This file is part of Moodle - http://moodle.org/
4 //
5 // Moodle is free software: you can redistribute it and/or modify
6 // it under the terms of the GNU General Public License as published by
7 // the Free Software Foundation, either version 3 of the License, or
8 // (at your option) any later version.
9 //
10 // Moodle is distributed in the hope that it will be useful,
11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13 // GNU General Public License for more details.
14 //
15 // You should have received a copy of the GNU General Public License
16 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
18 /**
19  * @package    moodlecore
20  * @subpackage backup-factories
21  * @copyright  2010 onwards Eloy Lafuente (stronk7) {@link http://stronk7.com}
22  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
23  */
25 /**
26  * Non instantiable helper class providing different backup checks
27  *
28  * This class contains various static methods available in order to easily
29  * perform a bunch of backup architecture tests
30  *
31  * TODO: Finish phpdocs
32  */
33 abstract class backup_check {
35     public static function check_format_and_type($format, $type) {
36         global $CFG;
38         $file = $CFG->dirroot . '/backup/' . $format . '/backup_plan_builder.class.php';
39         if (! file_exists($file)) {
40             throw new backup_controller_exception('backup_check_unsupported_format', $format);
41         }
42         require_once($file);
43         if (!in_array($type, backup_plan_builder::supported_backup_types())) {
44             throw new backup_controller_exception('backup_check_unsupported_type', $type);
45         }
47         require_once($CFG->dirroot . '/backup/moodle2/backup_plan_builder.class.php');
48     }
50     public static function check_id($type, $id) {
51         global $DB;
52         switch ($type) {
53             case backup::TYPE_1ACTIVITY:
54                 // id must exist in course_modules table
55                 if (! $DB->record_exists('course_modules', array('id' => $id))) {
56                     throw new backup_controller_exception('backup_check_module_not_exists', $id);
57                 }
58                 break;
59             case backup::TYPE_1SECTION:
60                 // id must exist in course_sections table
61                 if (! $DB->record_exists('course_sections', array('id' => $id))) {
62                     throw new backup_controller_exception('backup_check_section_not_exists', $id);
63                 }
64                 break;
65             case backup::TYPE_1COURSE:
66                 // id must exist in course table
67                 if (! $DB->record_exists('course', array('id' => $id))) {
68                     throw new backup_controller_exception('backup_check_course_not_exists', $id);
69                 }
70                 break;
71             default:
72                 throw new backup_controller_exception('backup_check_incorrect_type', $type);
73         }
74         return true;
75     }
77     public static function check_user($userid) {
78         global $DB;
79         // userid must exist in user table
80         if (! $DB->record_exists('user', array('id' => $userid))) {
81             throw new backup_controller_exception('backup_check_user_not_exists', $userid);
82         }
83         return true;
84     }
86     public static function check_security($backup_controller, $apply) {
87         global $DB;
89         if (! $backup_controller instanceof backup_controller) {
90             throw new backup_controller_exception('backup_check_security_requires_backup_controller');
91         }
92         $backup_controller->log('checking plan security', backup::LOG_INFO);
94         // Some handy vars
95         $type     = $backup_controller->get_type();
96         $mode     = $backup_controller->get_mode();
97         $courseid = $backup_controller->get_courseid();
98         $coursectx= get_context_instance(CONTEXT_COURSE, $courseid);
99         $userid   = $backup_controller->get_userid();
100         $id       = $backup_controller->get_id(); // courseid / sectionid / cmid
102         // Note: all the checks along the function MUST be performed for $userid, that
103         // is the user who "requested" the course backup, not current $USER at all!!
105         // First of all, check the main backup[course|section|activity] principal caps
106         // Lacking the corresponding one makes this to break with exception always
107         switch ($type) {
108             case backup::TYPE_1COURSE :
109                 $DB->get_record('course', array('id' => $id), '*', MUST_EXIST); // course exists
110                 if (!has_capability('moodle/backup:backupcourse', $coursectx, $userid)) {
111                     $a = new stdclass();
112                     $a->userid = $userid;
113                     $a->courseid = $courseid;
114                     $a->capability = 'moodle/backup:backupcourse';
115                     throw new backup_controller_exception('backup_user_missing_capability', $a);
116                 }
117                 break;
118             case backup::TYPE_1SECTION :
119                 $DB->get_record('course_sections', array('course' => $courseid, 'id' => $id), '*', MUST_EXIST); // sec exists
120                 if (!has_capability('moodle/backup:backupsection', $coursectx, $userid)) {
121                     $a = new stdclass();
122                     $a->userid = $userid;
123                     $a->courseid = $courseid;
124                     $a->capability = 'moodle/backup:backupsection';
125                     throw new backup_controller_exception('backup_user_missing_capability', $a);
126                 }
127                 break;
128             case backup::TYPE_1ACTIVITY :
129                 get_coursemodule_from_id(null, $id, $courseid, false, MUST_EXIST); // cm exists
130                 $modulectx = get_context_instance(CONTEXT_MODULE, $id);
131                 if (!has_capability('moodle/backup:backupactivity', $modulectx, $userid)) {
132                     $a = new stdclass();
133                     $a->userid = $userid;
134                     $a->cmid = $id;
135                     $a->capability = 'moodle/backup:backupactivity';
136                     throw new backup_controller_exception('backup_user_missing_capability', $a);
137                 }
138                 break;
139             default :
140                 print_error('unknownbackuptype');
141         }
143         // Now, if backup mode is hub or import, check userid has permissions for those modes
144         switch ($mode) {
145             case backup::MODE_HUB:
146                 if (!has_capability('moodle/backup:backuptargethub', $coursectx, $userid)) {
147                     $a = new stdclass();
148                     $a->userid = $userid;
149                     $a->courseid = $courseid;
150                     $a->capability = 'moodle/backup:backuptargethub';
151                     throw new backup_controller_exception('backup_user_missing_capability', $a);
152                 }
153                 break;
154             case backup::MODE_IMPORT:
155                 if (!has_capability('moodle/backup:backuptargetimport', $coursectx, $userid)) {
156                     $a = new stdclass();
157                     $a->userid = $userid;
158                     $a->courseid = $courseid;
159                     $a->capability = 'moodle/backup:backuptargetimport';
160                     throw new backup_controller_exception('backup_user_missing_capability', $a);
161                 }
162                 break;
163         }
165         // Now, enforce 'moodle/backup:userinfo' to 'users' setting, applying changes if allowed,
166         // else throwing exception
167         $userssetting = $backup_controller->get_plan()->get_setting('users');
168         $prevvalue    = $userssetting->get_value();
169         $prevstatus   = $userssetting->get_status();
170         $hasusercap   = has_capability('moodle/backup:userinfo', $coursectx, $userid);
172         // If setting is enabled but user lacks permission
173         if (!$hasusercap && $prevvalue) { // If user has not the capability and setting is enabled
174             // Now analyse if we are allowed to apply changes or must stop with exception
175             if (!$apply) { // Cannot apply changes, throw exception
176                 $a = new stdclass();
177                 $a->setting = 'users';
178                 $a->value = $prevvalue;
179                 $a->capability = 'moodle/backup:userinfo';
180                 throw new backup_controller_exception('backup_setting_value_wrong_for_capability', $a);
182             } else { // Can apply changes
183                 $userssetting->set_value(false);                              // Set the value to false
184                 $userssetting->set_status(base_setting::LOCKED_BY_PERMISSION);// Set the status to locked by perm
185             }
186         }
188         // Now, enforce 'moodle/backup:anonymise' to 'anonymise' setting, applying changes if allowed,
189         // else throwing exception
190         $anonsetting = $backup_controller->get_plan()->get_setting('anonymize');
191         $prevvalue   = $userssetting->get_value();
192         $prevstatus  = $userssetting->get_status();
193         $hasanoncap  = has_capability('moodle/backup:anonymise', $coursectx, $userid);
195         // If setting is enabled but user lacks permission
196         if (!$hasanoncap && $prevvalue) { // If user has not the capability and setting is enabled
197             // Now analyse if we are allowed to apply changes or must stop with exception
198             if (!$apply) { // Cannot apply changes, throw exception
199                 $a = new stdclass();
200                 $a->setting = 'anonymize';
201                 $a->value = $prevvalue;
202                 $a->capability = 'moodle/backup:anonymise';
203                 throw new backup_controller_exception('backup_setting_value_wrong_for_capability', $a);
205             } else { // Can apply changes
206                 $anonsetting->set_value(false);                              // Set the value to false
207                 $anonsetting->set_status(base_setting::LOCKED_BY_PERMISSION);// Set the status to locked by perm
208             }
209         }
211         // Now, if mode is HUB or IMPORT, and still we are including users in backup, turn them off
212         // Defaults processing should have handled this, but we need to be 100% sure
213         if ($mode == backup::MODE_IMPORT || $mode == backup::MODE_HUB) {
214             $userssetting = $backup_controller->get_plan()->get_setting('users');
215             if ($userssetting->get_value()) {
216                 $userssetting->set_value(false);                              // Set the value to false
217                 $userssetting->set_status(base_setting::LOCKED_BY_PERMISSION);// Set the status to locked by perm
218             }
219         }
221         return true;
222     }