MDL-23437 backup - restore security checks
[moodle.git] / backup / util / checks / backup_check.class.php
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1<?php
2
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/>.
17
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 */
24
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 */
33abstract class backup_check {
34
35 public static function check_format_and_type($format, $type) {
36 global $CFG;
37
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', $type);
45 }
46
47 require_once($CFG->dirroot . '/backup/moodle2/backup_plan_builder.class.php');
48 }
49
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', $type);
73 }
74 return true;
75 }
76
77 public static function check_user($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', $userid);
82 }
83 return true;
84 }
85
86 public static function check_security($backup_controller, $apply) {
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87 global $DB;
88
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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);
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93
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
101
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 $USER at all!!
104
105 // First of all, check the main backup[course|section|activity] principal caps
106 // Lacking the corresponding one makes this to break with exception always
107 switch ($type) {
108 case backup::TYPE_1COURSE :
109 $DB->get_record('course', array('id' => $id), '*', MUST_EXIST); // course exists
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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 }
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117 break;
118 case backup::TYPE_1SECTION :
119 $DB->get_record('course_sections', array('course' => $courseid, 'id' => $id), '*', MUST_EXIST); // sec exists
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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 }
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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);
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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', $a);
137 }
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138 break;
139 default :
140 print_error('unknownbackuptype');
141 }
142
143 // Now, if backup mode is hub or import, check userid has permissions for those modes
144 switch ($mode) {
145 case backup::MODE_HUB:
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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 }
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153 break;
154 case backup::MODE_IMPORT:
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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 }
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162 break;
163 }
164
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, $userid);
171
172 // If setting is enabled but user lacks permission
173 if (!$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);
181
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 }
187
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, $userid);
194
195 // If setting is enabled but user lacks permission
196 if (!$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);
204
205 } else { // Can apply changes
206 $anonsetting->set_value(false); // Set the value to false
207 $anonsetting->set_status(base_setting::LOCKED_BY_PERMISSION);// Set the status to locked by perm
208 }
209 }
210
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211 // Now, if mode is HUB or IMPORT, and still we are including users in backup, turn them off
212 // Defaults processing should have handled this, but we need to be 100% sure
213 if ($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 }
220
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221 return true;
222 }
223}