Search moodle.org's
Developer Documentation

See Release Notes

  • 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.
<?php

/**
 * -----XML-Envelope---------------------------------
 * |                                                |
 * |    Encrypted-Symmetric-key----------------     |
 * |    |_____________________________________|     |
 * |                                                |
 * |    Encrypted data-------------------------     |
 * |    |                                     |     |
 * |    |  -XML-Envelope------------------    |     |
 * |    |  |                             |    |     |
 * |    |  |  --Signature-------------   |    |     |
 * |    |  |  |______________________|   |    |     |
 * |    |  |                             |    |     |
 * |    |  |  --Signed-Payload--------   |    |     |
 * |    |  |  |                      |   |    |     |
 * |    |  |  |   XML-RPC Request    |   |    |     |
 * |    |  |  |______________________|   |    |     |
 * |    |  |                             |    |     |
 * |    |  |_____________________________|    |     |
 * |    |_____________________________________|     |
 * |                                                |
 * |________________________________________________|
 *
 */

/* Strip encryption envelope (if present) and decrypt data
 *
 * @param string $rawpostdata The XML that the client sent
 *
 * @throws mnet_server_exception
 *
 * @return string XML with any encryption envolope removed
 */
function mnet_server_strip_encryption($rawpostdata) {
    $remoteclient = get_mnet_remote_client();
    $crypt_parser = new mnet_encxml_parser();
    $crypt_parser->parse($rawpostdata);
    $mnet = get_mnet_environment();

    if (!$crypt_parser->payload_encrypted) {
        return $rawpostdata;
    }

    // Make sure we know who we're talking to
    $host_record_exists = $remoteclient->set_wwwroot($crypt_parser->remote_wwwroot);

    if (false == $host_record_exists) {
        throw new mnet_server_exception(7020, 'wrong-wwwroot', $crypt_parser->remote_wwwroot);
    }

    // This key is symmetric, and is itself encrypted. Can be decrypted using our private key
    $key  = array_pop($crypt_parser->cipher);
    // This data is symmetrically encrypted, can be decrypted using the above key
    $data = array_pop($crypt_parser->cipher);

    $crypt_parser->free_resource();
    $payload          = '';    // Initialize payload var

    //                                          &$payload
    $isOpen = openssl_open(base64_decode($data), $payload, base64_decode($key), $mnet->get_private_key(), 'RC4');
    if ($isOpen) {
        $remoteclient->was_encrypted();
        return $payload;
    }

    // Decryption failed... let's try our archived keys
    $openssl_history = get_config('mnet', 'openssl_history');
    if(empty($openssl_history)) {
        $openssl_history = array();
        set_config('openssl_history', serialize($openssl_history), 'mnet');
    } else {
        $openssl_history = unserialize($openssl_history);
    }
    foreach($openssl_history as $keyset) {
        $keyresource = openssl_pkey_get_private($keyset['keypair_PEM']);
        $isOpen      = openssl_open(base64_decode($data), $payload, base64_decode($key), $keyresource, 'RC4');
        if ($isOpen) {
            // It's an older code, sir, but it checks out
            $remoteclient->was_encrypted();
            $remoteclient->encrypted_to($keyresource);
            $remoteclient->set_pushkey();
            return $payload;
        }
    }

    //If after all that we still couldn't decrypt the message, error out.
    throw new mnet_server_exception(7023, 'encryption-invalid');
}

/* Strip signature envelope (if present), try to verify any signature using our record of remote peer's public key.
 *
 * @param string $plaintextmessage XML envelope containing XMLRPC request and signature
 *
 * @return string XMLRPC request
 */
function mnet_server_strip_signature($plaintextmessage) {
    $remoteclient = get_mnet_remote_client();
    $sig_parser = new mnet_encxml_parser();
    $sig_parser->parse($plaintextmessage);

    if ($sig_parser->signature == '') {
        return $plaintextmessage;
    }

    // Record that the request was signed in some way
    $remoteclient->was_signed();

    // Load any information we have about this mnet peer
    $remoteclient->set_wwwroot($sig_parser->remote_wwwroot);

    $payload = base64_decode($sig_parser->data_object);
    $signature = base64_decode($sig_parser->signature);
    $certificate = $remoteclient->public_key;

    // If we don't have any certificate for the host, don't try to check the signature
    // Just return the parsed request
    if ($certificate == false) {
        return $payload;
    }

    // Does the signature match the data and the public cert?
    $signature_verified = openssl_verify($payload, $signature, $certificate);
    if ($signature_verified == 0) {
        // $signature was not generated for $payload using $certificate
        // Get the key the remote peer is currently publishing:
        $currkey = mnet_get_public_key($remoteclient->wwwroot, $remoteclient->application);
        // If the key the remote peer is currently publishing is different to $certificate
        if($currkey != $certificate) {
            // if pushkey is already set, it means the request was encrypted to an old key
            // in mnet_server_strip_encryption.
            // if we call refresh_key() here before pushing out our new key,
            // and the other site ALSO has a new key,
            // we'll get into an infinite keyswap loop
            // so push just bail here, and push out the new key.
            // the next request will get through to refresh_key
            if ($remoteclient->pushkey) {
                return false;
            }
            // Try and get the server's new key through trusted means
            $remoteclient->refresh_key();
            // If we did manage to re-key, try to verify the signature again using the new public key.
            $certificate = $remoteclient->public_key;
            $signature_verified = openssl_verify($payload, $signature, $certificate);
        }
    }

    if ($signature_verified == 1) {
        $remoteclient->signature_verified();
        $remoteclient->touch();
    }

    $sig_parser->free_resource();

    return $payload;
}

/**
 * Return the proper XML-RPC content to report an error in the local language.
 *
 * @param  int    $code   The ID code of the error message
 * @param  string $text   The full string of the error message (get_string will <b>not be called</b>)
 * @param  string $param  The $a param for the error message in the lang file
 * @return string $text   The text of the error message
 */
function mnet_server_fault($code, $text, $param = null) {
    if (!is_numeric($code)) {
        $code = 0;
    }
    $code = intval($code);
    return mnet_server_fault_xml($code, $text);
}

/**
 * Return the proper XML-RPC content to report an error.
 *
 * @param  int      $code   The ID code of the error message
 * @param  string   $text   The error message
 * @param  resource $privatekey The private key that should be used to sign the response
 * @return string   $text   The XML text of the error message
 */
function mnet_server_fault_xml($code, $text, $privatekey = null) {
    global $CFG;
    // Replace illegal XML chars - is this already in a lib somewhere?
    $text = str_replace(array('<','>','&','"',"'"), array('&lt;','&gt;','&amp;','&quot;','&apos;'), $text);

    $return = mnet_server_prepare_response('<?xml version="1.0"?>
<methodResponse>
   <fault>
      <value>
         <struct>
            <member>
               <name>faultCode</name>
               <value><int>'.$code.'</int></value>
            </member>
            <member>
               <name>faultString</name>
               <value><string>'.$text.'</string></value>
            </member>
         </struct>
      </value>
   </fault>
</methodResponse>', $privatekey);

    if ($code != 7025) { // new key responses
        mnet_debug("XMLRPC Error Response $code: $text");
        //mnet_debug($return);
    }

    return $return;
}


/**
 * Package a response in any required envelope, and return it to the client
 *
 * @param   string   $response      The XMLRPC response string
 * @param   resource $privatekey    The private key to sign the response with
 * @return  string                  The encoded response string
 */
function mnet_server_prepare_response($response, $privatekey = null) {
    $remoteclient = get_mnet_remote_client();
    if ($remoteclient->request_was_signed) {
        $response = mnet_sign_message($response, $privatekey);
    }

    if ($remoteclient->request_was_encrypted) {
        $response = mnet_encrypt_message($response, $remoteclient->public_key);
    }

    return $response;
}

/**
 * If security checks are passed, dispatch the request to the function/method
 *
 * The config variable 'mnet_dispatcher_mode' can be:
 * strict:      Only execute functions that are in specific files
 * off:         The default - don't execute anything
 *
 * @param  string  $payload    The XML-RPC request
 *
 * @throws mnet_server_exception
 *
 * @return                     No return val - just echo the response
 */
function mnet_server_dispatch($payload) {
    global $CFG, $DB;
    $remoteclient = get_mnet_remote_client();
< // xmlrpc_decode_request returns an array of parameters, and the $method < // variable (which is passed by reference) is instantiated with the value from < // the methodName tag in the xml payload < // xmlrpc_decode_request($xml, &$method) < $params = xmlrpc_decode_request($payload, $method);
> // Decode the request to method + params. > $method = null; > $params = null; > $encoder = new \PhpXmlRpc\Encoder(); > $orequest = $encoder->decodeXML($payload); // First, to internal PhpXmlRpc\Response structure. > if ($orequest && $orequest instanceof \PhpXmlRpc\Request) { > $method = $orequest->method(); > $numparams = $orequest->getNumParams(); > for ($i = 0; $i < $numparams; $i++) { > $params[] = $encoder->decode($orequest->getParam($i)); > } > }
// $method is something like: "mod/forum/lib.php/forum_add_instance" // $params is an array of parameters. A parameter might itself be an array. // Check that the method name consists of allowed characters only. // The method name must not begin with a / - avoid absolute paths // A dot character . is only allowed in the filename, i.e. something.php if (0 == preg_match("@^[A-Za-z0-9]+/[A-Za-z0-9/_\.-]+(\.php/)?[A-Za-z0-9_-]+$@",$method)) { throw new mnet_server_exception(713, 'nosuchfunction'); } if(preg_match("/^system\./", $method)) { $callstack = explode('.', $method); } else { $callstack = explode('/', $method); // callstack will look like array('mod', 'forum', 'lib.php', 'forum_add_instance'); } /** * What has the site administrator chosen as his dispatcher setting? * strict: Only execute functions that are in specific files * off: The default - don't execute anything */ ////////////////////////////////////// OFF if (!isset($CFG->mnet_dispatcher_mode) ) { set_config('mnet_dispatcher_mode', 'off'); throw new mnet_server_exception(704, 'nosuchservice'); } elseif ('off' == $CFG->mnet_dispatcher_mode) { throw new mnet_server_exception(704, 'nosuchservice'); ////////////////////////////////////// SYSTEM METHODS } elseif ($callstack[0] == 'system') { $functionname = $callstack[1];
< $xmlrpcserver = xmlrpc_server_create();
> $xmlrpcserver = new \PhpXmlRpc\Server(); > $xmlrpcserver->functions_parameters_type = 'epivals'; > $xmlrpcserver->compress_response = false;
// register all the system methods $systemmethods = array('listMethods', 'methodSignature', 'methodHelp', 'listServices', 'listFiles', 'retrieveFile', 'keyswap'); foreach ($systemmethods as $m) { // I'm adding the canonical xmlrpc references here, however we've // already forbidden that the period (.) should be allowed in the call // stack, so if someone tries to access our XMLRPC in the normal way, // they'll already have received a RPC server fault message. // Maybe we should allow an easement so that regular XMLRPC clients can // call our system methods, and find out what we have to offer? $handler = 'mnet_system'; if ($m == 'keyswap') { $handler = 'mnet_keyswap'; } if ($method == 'system.' . $m || $method == 'system/' . $m) {
< xmlrpc_server_register_method($xmlrpcserver, $method, $handler); < $response = xmlrpc_server_call_method($xmlrpcserver, $payload, $remoteclient, array("encoding" => "utf-8"));
> $xmlrpcserver->add_to_map($method, $handler); > $xmlrpcserver->user_data = $remoteclient; > $response = $xmlrpcserver->service($payload, true);
$response = mnet_server_prepare_response($response); echo $response;
< xmlrpc_server_destroy($xmlrpcserver);
return; } } throw new mnet_server_exception(7018, 'nosuchfunction'); //////////////////////////////////// NORMAL PLUGIN DISPATCHER } else { // anything else comes from some sort of plugin if ($rpcrecord = $DB->get_record('mnet_rpc', array('xmlrpcpath' => $method))) { $response = mnet_server_invoke_plugin_method($method, $callstack, $rpcrecord, $payload); $response = mnet_server_prepare_response($response); echo $response; return; // if the rpc record isn't found, check to see if dangerous mode is on ////////////////////////////////////// DANGEROUS } else if ('dangerous' == $CFG->mnet_dispatcher_mode && $remoteclient->plaintext_is_ok()) { $functionname = array_pop($callstack); $filename = clean_param(implode('/',$callstack), PARAM_PATH); if (0 == preg_match("/php$/", $filename)) { // Filename doesn't end in 'php'; possible attack? // Generate error response - unable to locate function throw new mnet_server_exception(7012, 'nosuchfunction'); } // The call stack holds the path to any include file $includefile = $CFG->dirroot.'/'.$filename; $response = mnet_server_invoke_dangerous_method($includefile, $functionname, $method, $payload); echo $response; return; } } throw new mnet_server_exception(7012, 'nosuchfunction'); } /** * Execute the system functions - mostly for introspection * * @param string $method XMLRPC method name, e.g. system.listMethods * @param array $params Array of parameters from the XMLRPC request * @param string $hostinfo Hostinfo object from the mnet_host table * * @throws mnet_server_exception * * @return mixed Response data - any kind of PHP variable */ function mnet_system($method, $params, $hostinfo) { global $CFG, $DB; if (empty($hostinfo)) return array(); $id_list = $hostinfo->id; if (!empty($CFG->mnet_all_hosts_id)) { $id_list .= ', '.$CFG->mnet_all_hosts_id; } if ('system.listMethods' == $method || 'system/listMethods' == $method) { $query = ' SELECT DISTINCT rpc.functionname, rpc.xmlrpcpath FROM {mnet_host2service} h2s JOIN {mnet_service2rpc} s2r ON h2s.serviceid = s2r.serviceid JOIN {mnet_rpc} rpc ON s2r.rpcid = rpc.id JOIN {mnet_service} svc ON svc.id = s2r.serviceid WHERE h2s.hostid in ('.$id_list .') AND h2s.publish = 1 AND rpc.enabled = 1 ' . ((count($params) > 0) ? 'AND svc.name = ? ' : '') . ' ORDER BY rpc.xmlrpcpath ASC'; if (count($params) > 0) { $params = array($params[0]); } $methods = array(); foreach ($DB->get_records_sql($query, $params) as $result) { $methods[] = $result->xmlrpcpath; } return $methods; } elseif (in_array($method, array('system.methodSignature', 'system/methodSignature', 'system.methodHelp', 'system/methodHelp'))) { $query = ' SELECT DISTINCT rpc.functionname, rpc.help, rpc.profile FROM {mnet_host2service} h2s, {mnet_service2rpc} s2r, {mnet_rpc} rpc WHERE rpc.xmlrpcpath = ? AND s2r.rpcid = rpc.id AND h2s.publish = 1 AND rpc.enabled = 1 AND h2s.serviceid = s2r.serviceid AND h2s.hostid in ('.$id_list .')'; $params = array($params[0]); if (!$result = $DB->get_record_sql($query, $params)) { return false; } if (strpos($method, 'methodSignature') !== false) { return unserialize($result->profile); } return $result->help; } elseif ('system.listServices' == $method || 'system/listServices' == $method) { $query = ' SELECT DISTINCT s.id, s.name, s.apiversion, h2s.publish, h2s.subscribe FROM {mnet_host2service} h2s, {mnet_service} s WHERE h2s.serviceid = s.id AND (h2s.publish = 1 OR h2s.subscribe = 1) AND h2s.hostid in ('.$id_list .') ORDER BY s.name ASC'; $params = array(); $result = $DB->get_records_sql($query, $params); $services = array(); if (is_array($result)) { foreach($result as $service) { $services[] = array('name' => $service->name, 'apiversion' => $service->apiversion, 'publish' => $service->publish, 'subscribe' => $service->subscribe); } } return $services; } throw new mnet_server_exception(7019, 'nosuchfunction'); } /** * Invoke a normal style plugin method * This will verify permissions first. * * @param string $method the full xmlrpc method that was called eg auth/mnet/auth.php/user_authorise * @param array $callstack the exploded callstack * @param stdclass $rpcrecord the record from mnet_rpc * * @return mixed the response from the invoked method */ function mnet_server_invoke_plugin_method($method, $callstack, $rpcrecord, $payload) { mnet_verify_permissions($rpcrecord); // will throw exceptions mnet_setup_dummy_method($method, $callstack, $rpcrecord); $methodname = array_pop($callstack);
< $xmlrpcserver = xmlrpc_server_create(); < xmlrpc_server_register_method($xmlrpcserver, $method, 'mnet_server_dummy_method'); < $response = xmlrpc_server_call_method($xmlrpcserver, $payload, $methodname, array("encoding" => "utf-8")); < xmlrpc_server_destroy($xmlrpcserver);
> $xmlrpcserver = new \PhpXmlRpc\Server(); > $xmlrpcserver->functions_parameters_type = 'epivals'; > $xmlrpcserver->compress_response = false; > > $xmlrpcserver->add_to_map($method, 'mnet_server_dummy_method'); > $xmlrpcserver->user_data = $methodname; > $response = $xmlrpcserver->service($payload, true); >
return $response; } /** * Initialize the object (if necessary), execute the method or function, and * return the response * * @param string $includefile The file that contains the object definition * @param string $methodname The name of the method to execute * @param string $method The full path to the method * @param string $payload The XML-RPC request payload * @param string $class The name of the class to instantiate (or false) * * @throws mnet_server_exception * * @return string The XML-RPC response */ function mnet_server_invoke_dangerous_method($includefile, $methodname, $method, $payload) { if (file_exists($CFG->dirroot . $includefile)) { require_once $CFG->dirroot . $includefile; // $callprefix matches the rpc convention // of not having a leading slash $callprefix = preg_replace('!^/!', '', $includefile); } else { throw new mnet_server_exception(705, "nosuchfile"); } if ($functionname != clean_param($functionname, PARAM_PATH)) { throw new mnet_server_exception(7012, "nosuchfunction"); } if (!function_exists($functionname)) { throw new mnet_server_exception(7012, "nosuchfunction"); }
< $xmlrpcserver = xmlrpc_server_create(); < xmlrpc_server_register_method($xmlrpcserver, $method, 'mnet_server_dummy_method'); < $response = xmlrpc_server_call_method($xmlrpcserver, $payload, $methodname, array("encoding" => "utf-8")); < xmlrpc_server_destroy($xmlrpcserver);
> > $xmlrpcserver = new \PhpXmlRpc\Server(); > $xmlrpcserver->functions_parameters_type = 'epivals'; > $xmlrpcserver->compress_response = false; > > $xmlrpcserver->add_to_map($method, 'mnet_server_dummy_method'); > $xmlrpcserver->user_data = $methodname; > $response = $xmlrpcserver->service($payload, true); >
return $response; } /** * Accepts a public key from a new remote host and returns the public key for * this host. If 'register all hosts' is turned on, it will bootstrap a record * for the remote host in the mnet_host table (if it's not already there) * * @param string $function XML-RPC requires this but we don't... discard! * @param array $params Array of parameters * $params[0] is the remote wwwroot * $params[1] is the remote public key * @return string The XML-RPC response */ function mnet_keyswap($function, $params) { global $CFG; $return = array(); $mnet = get_mnet_environment(); if (!empty($CFG->mnet_register_allhosts)) { $mnet_peer = new mnet_peer(); list($wwwroot, $pubkey, $application) = $params; $keyok = $mnet_peer->bootstrap($wwwroot, $pubkey, $application); if ($keyok) { $mnet_peer->commit(); } } return $mnet->public_key; } /** * Verify that the requested xmlrpc method can be called * This just checks the method exists in the rpc table and is enabled. * * @param stdclass $rpcrecord the record from mnet_rpc * * @throws mnet_server_exception */ function mnet_verify_permissions($rpcrecord) { global $CFG, $DB; $remoteclient = get_mnet_remote_client(); $id_list = $remoteclient->id; if (!empty($CFG->mnet_all_hosts_id)) { $id_list .= ', '.$CFG->mnet_all_hosts_id; }
> > // TODO: Change this to avoid the first column duplicate debugging, keeping current behaviour 100%.
$sql = "SELECT r.*, h2s.publish FROM {mnet_rpc} r JOIN {mnet_service2rpc} s2r ON s2r.rpcid = r.id LEFT JOIN {mnet_host2service} h2s ON h2s.serviceid = s2r.serviceid WHERE r.id = ? AND h2s.hostid in ($id_list)"; $params = array($rpcrecord->id); if (!$permission = $DB->get_record_sql($sql, $params)) { throw new mnet_server_exception(7012, "nosuchfunction"); } else if (!$permission->publish || !$permission->enabled) { throw new mnet_server_exception(707, "nosuchfunction"); } } /** * Figure out exactly what needs to be called and stashes it in $remoteclient * Does some further verification that the method is callable * * @param string $method the full xmlrpc method that was called eg auth/mnet/auth.php/user_authorise * @param array $callstack the exploded callstack * @param stdclass $rpcrecord the record from mnet_rpc * * @throws mnet_server_exception */ function mnet_setup_dummy_method($method, $callstack, $rpcrecord) { global $CFG; $remoteclient = get_mnet_remote_client(); // verify that the callpath in the stack matches our records // callstack will look like array('mod', 'forum', 'lib.php', 'forum_add_instance'); $path = core_component::get_plugin_directory($rpcrecord->plugintype, $rpcrecord->pluginname); $path = substr($path, strlen($CFG->dirroot)+1); // this is a bit hacky and fragile, it is not guaranteed that plugins are in dirroot array_pop($callstack); $providedpath = implode('/', $callstack); if ($providedpath != $path . '/' . $rpcrecord->filename) { throw new mnet_server_exception(705, "nosuchfile"); } if (!file_exists($CFG->dirroot . '/' . $providedpath)) { throw new mnet_server_exception(705, "nosuchfile"); } require_once($CFG->dirroot . '/' . $providedpath); if (!empty($rpcrecord->classname)) { if (!class_exists($rpcrecord->classname)) { throw new mnet_server_exception(708, 'nosuchclass'); } if (!$rpcrecord->static) { try { $object = new $rpcrecord->classname; } catch (Exception $e) { throw new mnet_server_exception(709, "classerror"); } if (!is_callable(array($object, $rpcrecord->functionname))) { throw new mnet_server_exception(706, "nosuchfunction"); } $remoteclient->object_to_call($object); } else { if (!is_callable(array($rpcrecord->classname, $rpcrecord->functionname))) { throw new mnet_server_exception(706, "nosuchfunction"); } $remoteclient->static_location($rpcrecord->classname); } } } /** * Dummy function for the XML-RPC dispatcher - use to call a method on an object * or to call a function * * Translate XML-RPC's strange function call syntax into a more straightforward * PHP-friendly alternative. This dummy function will be called by the * dispatcher, and can be used to call a method on an object, or just a function * * The methodName argument (eg. mnet/testlib/mnet_concatenate_strings) * is ignored. * * @throws mnet_server_exception * * @param string $methodname We discard this - see 'functionname' * @param array $argsarray Each element is an argument to the real * function * @param string $functionname The name of the PHP function you want to call * @return mixed The return value will be that of the real * function, whatever it may be. */ function mnet_server_dummy_method($methodname, $argsarray, $functionname) { $remoteclient = get_mnet_remote_client(); try { if (is_object($remoteclient->object_to_call)) { return @call_user_func_array(array($remoteclient->object_to_call,$functionname), $argsarray); } else if (!empty($remoteclient->static_location)) { return @call_user_func_array(array($remoteclient->static_location, $functionname), $argsarray); } else { return @call_user_func_array($functionname, $argsarray); } } catch (Exception $e) { exit(mnet_server_fault($e->getCode(), $e->getMessage())); } } /** * mnet server exception. extends moodle_exception, but takes slightly different arguments. * and unlike the rest of moodle, the actual int error code is used. * this exception should only be used during an xmlrpc server request, ie, not for client requests. */ class mnet_server_exception extends moodle_exception { /** * @param int $intcode the numerical error associated with this fault. this is <b>not</b> the string errorcode * @param string $langkey the error message in full (<b>get_string will not be used</b>) * @param string $module the language module, defaults to 'mnet' * @param mixed $a params for get_string */ public function __construct($intcode, $languagekey, $module='mnet', $a=null) { parent::__construct($languagekey, $module, '', $a); $this->code = $intcode; } }