MDL-35238 Compare the ZIP package content hash with the expected value

The expected value is returned as a part of available update info
(requires API version 1.1).

lib/pluginlib.php

@@ -1407,6 +1407,8 @@ class available_update_info {
     public $url = null;
     /** @var string|null optional URL of a ZIP package that can be downloaded and installed */
     public $download = null;
+    /** @var string|null of self::download is set, then this must be the MD5 hash of the ZIP */
+    public $downloadmd5 = null;
 
     /**
      * Creates new instance of the class
@@ -1529,7 +1531,7 @@ class available_update_deployer {
      *
      * All instances of {@link available_update_info} class always provide at least the
      * component name and component version. Additionally, we also need the URL to download
-     * the ZIP package from.
+     * the ZIP package from and MD5 hash of the ZIP's content.
      *
      * @param available_update_info $info
      * @return bool
@@ -1540,6 +1542,10 @@ class available_update_deployer {
             return false;
         }
 
+        if (empty($info->downloadmd5)) {
+            return false;
+        }
+
         return true;
     }
 
@@ -1626,6 +1632,7 @@ class available_update_deployer {
             'name' => $pluginname,
             'typeroot' => $pluginrootpaths[$plugintype],
             'package' => $info->download,
+            'md5' => $info->downloadmd5,
             'dataroot' => $CFG->dataroot,
             'dirroot' => $CFG->dirroot,
             'passfile' => $passfile,

mdeploy.php

@@ -45,6 +45,7 @@ class download_file_exception extends Exception {}
 class backup_folder_exception extends Exception {}
 class zip_exception extends Exception {}
 class filesystem_exception extends Exception {}
+class checksum_exception extends Exception {}
 
 
 // Various support classes /////////////////////////////////////////////////////
@@ -118,6 +119,7 @@ class input_manager extends singleton_pattern {
     const TYPE_RAW          = 'raw';    // Raw value, keep as is
     const TYPE_URL          = 'url';    // URL to a file
     const TYPE_PLUGIN       = 'plugin'; // Plugin name
+    const TYPE_MD5          = 'md5';    // MD5 hash
 
     /** @var input_cli_provider|input_http_provider the provider of the input */
     protected $inputprovider = null;
@@ -173,6 +175,7 @@ class input_manager extends singleton_pattern {
             array('d', 'dataroot', input_manager::TYPE_PATH, 'Full path to the dataroot (moodledata) directory'),
             array('h', 'help', input_manager::TYPE_FLAG, 'Prints usage information'),
             array('i', 'install', input_manager::TYPE_FLAG, 'Installation mode'),
+            array('m', 'md5', input_manager::TYPE_MD5, 'Expected MD5 hash of the ZIP package to deploy'),
             array('n', 'name', input_manager::TYPE_PLUGIN, 'Plugin name (the name of its folder)'),
             array('p', 'package', input_manager::TYPE_URL, 'URL to the ZIP package to deploy'),
             array('r', 'typeroot', input_manager::TYPE_PATH, 'Full path of the container for this plugin type'),
@@ -288,6 +291,12 @@ class input_manager extends singleton_pattern {
                 }
                 return $raw;
 
+            case input_manager::TYPE_MD5:
+                if (!preg_match('/^[a-f0-9]{32}$/', $raw)) {
+                    throw new invalid_option_exception('Invalid MD5 hash format');
+                }
+                return $raw;
+
             default:
                 throw new invalid_coding_exception('Unknown option type.');
 
@@ -654,9 +663,17 @@ class worker extends singleton_pattern {
             } else {
                 $this->log('cURL error ' . $this->curlerrno . ' ' . $this->curlerror);
                 $this->log('Unable to download the file');
+                throw new download_file_exception('Unable to download the ZIP package');
             }
 
-            // Compare MD5 checksum of the ZIP file - TODO
+            // Compare MD5 checksum of the ZIP file
+            $md5remote = $this->input->get_option('md5');
+            $md5local = md5_file($target);
+
+            if ($md5local !== $md5remote) {
+                $this->log('MD5 checksum failed. Expected: '.$md5remote.' Got: '.$md5local);
+                throw new checksum_exception('MD5 checksum failed');
+            }
 
             // Backup the current version of the plugin
             $plugintyperoot = $this->input->get_option('typeroot');

mdeploytest.php

@@ -135,6 +135,8 @@ class mdeploytest extends PHPUnit_Framework_TestCase {
                 'https://moodle.org/plugins/download.php/1292/mod_stampcoll_moodle23_2012062201.zip'
             ),
             array('file:///etc/passwd', input_manager::TYPE_URL, ''),
+
+            array('5e8d2ea4f50d154730100b1645fbad67', input_manager::TYPE_MD5, '5e8d2ea4f50d154730100b1645fbad67'),
         );
     }
 
@@ -155,6 +157,15 @@ class mdeploytest extends PHPUnit_Framework_TestCase {
         $input->cast_value($o, input_manager::TYPE_INT); // must throw exception
     }
 
+    /**
+     * @expectedException invalid_option_exception
+     */
+    public function test_cast_invalid_md5_value() {
+        $input = testable_input_manager::instance();
+        $invalid = 'this is not a valid md5 hash';
+        $input->cast_value($invalid, input_manager::TYPE_MD5); // must throw exception
+    }
+
     public function test_has_option() {
         $provider = input_fake_provider::instance();