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<?php
/**
* An XML-RPC client
*
* @author Donal McMullan donal@catalyst.net.nz
* @version 0.0.1
* @license http://www.gnu.org/copyleft/gpl.html GNU Public License
* @package mnet
*/
require_once $CFG->dirroot.'/mnet/lib.php';
/**
* Class representing an XMLRPC request against a remote machine
*/
class mnet_xmlrpc_client {
var $method = '';
var $params = array();
var $timeout = 60;
var $error = array();
var $response = '';
var $mnet = null;
/**
* Constructor returns true
*/
function mnet_xmlrpc_client() {
// make sure we've got this set up before we try and do anything else
$this->mnet = get_mnet_environment();
return true;
}
/**
* Allow users to override the default timeout
* @param int $timeout Request timeout in seconds
* $return bool True if param is an integer or integer string
*/
function set_timeout($timeout) {
if (!is_integer($timeout)) {
if (is_numeric($timeout)) {
$this->timeout = (integer)$timeout;
return true;
}
return false;
}
$this->timeout = $timeout;
return true;
}
/**
* Set the path to the method or function we want to execute on the remote
* machine. Examples:
* mod/scorm/functionname
* auth/mnet/methodname
* In the case of auth and enrolment plugins, an object will be created and
* the method on that object will be called
*/
function set_method($xmlrpcpath) {
if (is_string($xmlrpcpath)) {
$this->method = $xmlrpcpath;
$this->params = array();
return true;
}
$this->method = '';
$this->params = array();
return false;
}
/**
* Add a parameter to the array of parameters.
*
* @param string $argument A transport ID, as defined in lib.php
* @param string $type The argument type, can be one of:
* none
* empty
* base64
* boolean
* datetime
* double
* int
* string
* array
* struct
* In its weakly-typed wisdom, PHP will (currently)
* ignore everything except datetime and base64
* @return bool True on success
*/
function add_param($argument, $type = 'string') {
$allowed_types = array('none',
'empty',
'base64',
'boolean',
'datetime',
'double',
'int',
'i4',
'string',
'array',
'struct');
if (!in_array($type, $allowed_types)) {
return false;
}
if ($type != 'datetime' && $type != 'base64') {
$this->params[] = $argument;
return true;
}
// Note weirdness - The type of $argument gets changed to an object with
// value and type properties.
// bool xmlrpc_set_type ( string &value, string type )
xmlrpc_set_type($argument, $type);
$this->params[] = $argument;
return true;
}
/**
* Send the request to the server - decode and return the response
*
* @param object $mnet_peer A mnet_peer object with details of the
* remote host we're connecting to
* @return mixed A PHP variable, as returned by the
* remote function
*/
function send($mnet_peer) {
global $CFG, $DB;
if (!$this->permission_to_call($mnet_peer)) {
mnet_debug("tried and wasn't allowed to call a method on $mnet_peer->wwwroot");
return false;
}
$this->requesttext = xmlrpc_encode_request($this->method, $this->params, array("encoding" => "utf-8", "escaping" => "markup"));
$this->signedrequest = mnet_sign_message($this->requesttext);
$this->encryptedrequest = mnet_encrypt_message($this->signedrequest, $mnet_peer->public_key);
$httprequest = $this->prepare_http_request($mnet_peer);
curl_setopt($httprequest, CURLOPT_POSTFIELDS, $this->encryptedrequest);
$timestamp_send = time();
mnet_debug("about to send the curl request");
$this->rawresponse = curl_exec($httprequest);
mnet_debug("managed to complete a curl request");
$timestamp_receive = time();
if ($this->rawresponse === false) {
$this->error[] = curl_errno($httprequest) .':'. curl_error($httprequest);
return false;
}
curl_close($httprequest);
$this->rawresponse = trim($this->rawresponse);
$mnet_peer->touch();
$crypt_parser = new mnet_encxml_parser();
$crypt_parser->parse($this->rawresponse);
// If we couldn't parse the message, or it doesn't seem to have encrypted contents,
// give the most specific error msg available & return
if (!$crypt_parser->payload_encrypted) {
if (! empty($crypt_parser->remoteerror)) {
$this->error[] = '4: remote server error: ' . $crypt_parser->remoteerror;
} else if (! empty($crypt_parser->error)) {
$crypt_parser_error = $crypt_parser->error[0];
$message = '3:XML Parse error in payload: '.$crypt_parser_error['string']."\n";
if (array_key_exists('lineno', $crypt_parser_error)) {
$message .= 'At line number: '.$crypt_parser_error['lineno']."\n";
}
if (array_key_exists('line', $crypt_parser_error)) {
$message .= 'Which reads: '.$crypt_parser_error['line']."\n";
}
$this->error[] = $message;
} else {
$this->error[] = '1:Payload not encrypted ';
}
$crypt_parser->free_resource();
return false;
}
$key = array_pop($crypt_parser->cipher);
$data = array_pop($crypt_parser->cipher);
$crypt_parser->free_resource();
// Initialize payload var
$decryptedenvelope = '';
// &$decryptedenvelope
$isOpen = openssl_open(base64_decode($data), $decryptedenvelope, base64_decode($key), $this->mnet->get_private_key());
if (!$isOpen) {
// 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), $decryptedenvelope, base64_decode($key), $keyresource);
if ($isOpen) {
// It's an older code, sir, but it checks out
break;
}
}
}
if (!$isOpen) {
trigger_error("None of our keys could open the payload from host {$mnet_peer->wwwroot} with id {$mnet_peer->id}.");
$this->error[] = '3:No key match';
return false;
}
if (strpos(substr($decryptedenvelope, 0, 100), '<signedMessage>')) {
$sig_parser = new mnet_encxml_parser();
$sig_parser->parse($decryptedenvelope);
} else {
$this->error[] = '2:Payload not signed: ' . $decryptedenvelope;
return false;
}
// Margin of error is the time it took the request to complete.
$margin_of_error = $timestamp_receive - $timestamp_send;
// Guess the time gap between sending the request and the remote machine
// executing the time() function. Marginally better than nothing.
$hysteresis = ($margin_of_error) / 2;
$remote_timestamp = $sig_parser->remote_timestamp - $hysteresis;
$time_offset = $remote_timestamp - $timestamp_send;
if ($time_offset > 0) {
$threshold = get_config('mnet', 'drift_threshold');
if(empty($threshold)) {
// We decided 15 seconds was a pretty good arbitrary threshold
// for time-drift between servers, but you can customize this in
// the config_plugins table. It's not advised though.
set_config('drift_threshold', 15, 'mnet');
$threshold = 15;
}
if ($time_offset > $threshold) {
$this->error[] = '6:Time gap with '.$mnet_peer->name.' ('.$time_offset.' seconds) is greater than the permitted maximum of '.$threshold.' seconds';
return false;
}
}
$this->xmlrpcresponse = base64_decode($sig_parser->data_object);
$this->response = xmlrpc_decode($this->xmlrpcresponse);
// xmlrpc errors are pushed onto the $this->error stack
if (is_array($this->response) && array_key_exists('faultCode', $this->response)) {
// The faultCode 7025 means we tried to connect with an old SSL key
// The faultString is the new key - let's save it and try again
// The re_key attribute stops us from getting into a loop
if($this->response['faultCode'] == 7025 && empty($mnet_peer->re_key)) {
mnet_debug('recieved an old-key fault, so trying to get the new key and update our records');
// If the new certificate doesn't come thru clean_param() unmolested, error out
if($this->response['faultString'] != clean_param($this->response['faultString'], PARAM_PEM)) {
$this->error[] = $this->response['faultCode'] . " : " . $this->response['faultString'];
}
$record = new stdClass();
$record->id = $mnet_peer->id;
$record->public_key = $this->response['faultString'];
$details = openssl_x509_parse($record->public_key);
if(!isset($details['validTo_time_t'])) {
$this->error[] = $this->response['faultCode'] . " : " . $this->response['faultString'];
}
$record->public_key_expires = $details['validTo_time_t'];
$DB->update_record('mnet_host', $record);
// Create a new peer object populated with the new info & try re-sending the request
$rekeyed_mnet_peer = new mnet_peer();
$rekeyed_mnet_peer->set_id($record->id);
$rekeyed_mnet_peer->re_key = true;
return $this->send($rekeyed_mnet_peer);
}
if (!empty($CFG->mnet_rpcdebug)) {
if (get_string_manager()->string_exists('error'.$this->response['faultCode'], 'mnet')) {
$guidance = get_string('error'.$this->response['faultCode'], 'mnet');
} else {
$guidance = '';
}
} else {
$guidance = '';
}
$this->error[] = $this->response['faultCode'] . " : " . $this->response['faultString'] ."\n".$guidance;
}
// ok, it's signed, but is it signed with the right certificate ?
// do this *after* we check for an out of date key
$verified = openssl_verify($this->xmlrpcresponse, base64_decode($sig_parser->signature), $mnet_peer->public_key);
if ($verified != 1) {
$this->error[] = 'Invalid signature';
}
return empty($this->error);
}
/**
* Check that we are permitted to call method on specified peer
*
* @param object $mnet_peer A mnet_peer object with details of the remote host we're connecting to
* @return bool True if we permit calls to method on specified peer, False otherwise.
*/
function permission_to_call($mnet_peer) {
global $DB, $CFG, $USER;
// Executing any system method is permitted.
$system_methods = array('system/listMethods', 'system/methodSignature', 'system/methodHelp', 'system/listServices');
if (in_array($this->method, $system_methods) ) {
return true;
}
$hostids = array($mnet_peer->id);
if (!empty($CFG->mnet_all_hosts_id)) {
$hostids[] = $CFG->mnet_all_hosts_id;
}
// At this point, we don't care if the remote host implements the
// method we're trying to call. We just want to know that:
// 1. The method belongs to some service, as far as OUR host knows
// 2. We are allowed to subscribe to that service on this mnet_peer
list($hostidsql, $hostidparams) = $DB->get_in_or_equal($hostids);
$sql = "SELECT r.id
FROM {mnet_remote_rpc} r
INNER JOIN {mnet_remote_service2rpc} s2r ON s2r.rpcid = r.id
INNER JOIN {mnet_host2service} h2s ON h2s.serviceid = s2r.serviceid
WHERE r.xmlrpcpath = ?
AND h2s.subscribe = ?
AND h2s.hostid $hostidsql";
$params = array($this->method, 1);
$params = array_merge($params, $hostidparams);
if ($DB->record_exists_sql($sql, $params)) {
return true;
}
$this->error[] = '7:User with ID '. $USER->id .
' attempted to call unauthorised method '.
$this->method.' on host '.
$mnet_peer->wwwroot;
return false;
}
/**
* Generate a curl handle and prepare it for sending to an mnet host
*
* @param object $mnet_peer A mnet_peer object with details of the remote host the request will be sent to
* @return cURL handle - the almost-ready-to-send http request
*/
function prepare_http_request ($mnet_peer) {
$this->uri = $mnet_peer->wwwroot . $mnet_peer->application->xmlrpc_server_url;
// Initialize request the target URL
$httprequest = curl_init($this->uri);
curl_setopt($httprequest, CURLOPT_TIMEOUT, $this->timeout);
curl_setopt($httprequest, CURLOPT_RETURNTRANSFER, true);
curl_setopt($httprequest, CURLOPT_POST, true);
curl_setopt($httprequest, CURLOPT_USERAGENT, 'Moodle');
curl_setopt($httprequest, CURLOPT_HTTPHEADER, array("Content-Type: text/xml charset=UTF-8"));
curl_setopt($httprequest, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($httprequest, CURLOPT_SSL_VERIFYHOST, 0);
return $httprequest;
}
}
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