mnet/lib.php

   1 <?php
   2 /**
   3  * Library functions for mnet
   4  *
   5  * @author  Donal McMullan  donal@catalyst.net.nz
   6  * @version 0.0.1
   7  * @license http://www.gnu.org/copyleft/gpl.html GNU Public License
   8  * @package mnet
   9  */
  10 require_once $CFG->dirroot.'/mnet/xmlrpc/xmlparser.php';
  11 require_once $CFG->dirroot.'/mnet/peer.php';
  12 require_once $CFG->dirroot.'/mnet/environment.php';
  13
  14 /// CONSTANTS ///////////////////////////////////////////////////////////
  15
  16 define('RPC_OK',                0);
  17 define('RPC_NOSUCHFILE',        1);
  18 define('RPC_NOSUCHCLASS',       2);
  19 define('RPC_NOSUCHFUNCTION',    3);
  20 define('RPC_FORBIDDENFUNCTION', 4);
  21 define('RPC_NOSUCHMETHOD',      5);
  22 define('RPC_FORBIDDENMETHOD',   6);
  23
  24 $MNET = new mnet_environment();
  25 $MNET->init();
  26
  27 /**
  28  * Strip extraneous detail from a URL or URI and return the hostname
  29  *
  30  * @param  string  $uri  The URI of a file on the remote computer, optionally
  31  *                       including its http:// prefix like
  32  *                       http://www.example.com/index.html
  33  * @return string        Just the hostname
  34  */
  35 function mnet_get_hostname_from_uri($uri = null) {
  36     $count = preg_match("@^(?:http[s]?://)?([A-Z0-9\-\.]+).*@i", $uri, $matches);
  37     if ($count > 0) return $matches[1];
  38     return false;
  39 }
  40
  41 /**
  42  * Get the remote machine's SSL Cert
  43  *
  44  * @param  string  $uri     The URI of a file on the remote computer, including
  45  *                          its http:// or https:// prefix
  46  * @return string           A PEM formatted SSL Certificate.
  47  */
  48 function mnet_get_public_key($uri) {
  49     global $CFG, $MNET;
  50     // The key may be cached in the mnet_set_public_key function...
  51     // check this first
  52     $key = mnet_set_public_key($uri);
  53     if ($key != false) {
  54         return $key;
  55     }
  56
  57     $rq = xmlrpc_encode_request('system/keyswap', array($CFG->wwwroot, $MNET->public_key), array("encoding" => "utf-8"));
  58     $ch = curl_init($uri.'/mnet/xmlrpc/server.php');
  59
  60     curl_setopt($ch, CURLOPT_TIMEOUT, 60);
  61     curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
  62     curl_setopt($ch, CURLOPT_POST, true);
  63     curl_setopt($ch, CURLOPT_USERAGENT, 'Moodle');
  64     curl_setopt($ch, CURLOPT_POSTFIELDS, $rq);
  65     curl_setopt($ch, CURLOPT_HTTPHEADER, array("Content-Type: text/xml charset=UTF-8"));
  66     curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
  67     curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
  68
  69     $res = xmlrpc_decode(curl_exec($ch));
  70     curl_close($ch);
  71
  72     if (!is_array($res)) { // ! error
  73         $public_certificate = $res;
  74         $credentials=array();
  75         if (strlen(trim($public_certificate))) {
  76             $credentials = openssl_x509_parse($public_certificate);
  77             $host = $credentials['subject']['CN'];
  78             if (strpos($uri, $host) !== false) {
  79                 mnet_set_public_key($uri, $public_certificate);
  80                 return $public_certificate;
  81             }
  82         }
  83     }
  84     return false;
  85 }
  86
  87 /**
  88  * Store a URI's public key in a static variable, or retrieve the key for a URI
  89  *
  90  * @param  string  $uri  The URI of a file on the remote computer, including its
  91  *                       https:// prefix
  92  * @param  mixed   $key  A public key to store in the array OR null. If the key
  93  *                       is null, the function will return the previously stored
  94  *                       key for the supplied URI, should it exist.
  95  * @return mixed         A public key OR true/false.
  96  */
  97 function mnet_set_public_key($uri, $key = null) {
  98     static $keyarray = array();
  99     if (isset($keyarray[$uri]) && empty($key)) {
 100         return $keyarray[$uri];
 101     } elseif (!empty($key)) {
 102         $keyarray[$uri] = $key;
 103         return true;
 104     }
 105     return false;
 106 }
 107
 108 /**
 109  * Sign a message and return it in an XML-Signature document
 110  *
 111  * This function can sign any content, but it was written to provide a system of
 112  * signing XML-RPC request and response messages. The message will be base64
 113  * encoded, so it does not need to be text.
 114  *
 115  * We compute the SHA1 digest of the message.
 116  * We compute a signature on that digest with our private key.
 117  * We link to the public key that can be used to verify our signature.
 118  * We base64 the message data.
 119  * We identify our wwwroot - this must match our certificate's CN
 120  *
 121  * The XML-RPC document will be parceled inside an XML-SIG document, which holds
 122  * the base64_encoded XML as an object, the SHA1 digest of that document, and a
 123  * signature of that document using the local private key. This signature will
 124  * uniquely identify the RPC document as having come from this server.
 125  *
 126  * See the {@Link http://www.w3.org/TR/xmldsig-core/ XML-DSig spec} at the W3c
 127  * site
 128  *
 129  * @param  string   $message              The data you want to sign
 130  * @return string                         An XML-DSig document
 131  */
 132 function mnet_sign_message($message) {
 133     global $CFG, $MNET;
 134     $digest = sha1($message);
 135     $sig = $MNET->sign_message($message);
 136
 137     $message = '<?xml version="1.0" encoding="iso-8859-1"?>
 138     <signedMessage>
 139         <Signature Id="MoodleSignature" xmlns="http://www.w3.org/2000/09/xmldsig#">
 140             <SignedInfo>
 141                 <CanonicalizationMethod Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315"/>
 142                 <SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#dsa-sha1"/>
 143                 <Reference URI="#XMLRPC-MSG">
 144                     <DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/>
 145                     <DigestValue>'.$digest.'</DigestValue>
 146                 </Reference>
 147             </SignedInfo>
 148             <SignatureValue>'.base64_encode($sig).'</SignatureValue>
 149             <KeyInfo>
 150                 <RetrievalMethod URI="'.$CFG->wwwroot.'/mnet/publickey.php"/>
 151             </KeyInfo>
 152         </Signature>
 153         <object ID="XMLRPC-MSG">'.base64_encode($message).'</object>
 154         <wwwroot>'.$MNET->wwwroot.'</wwwroot>
 155         <timestamp>'.time().'</timestamp>
 156     </signedMessage>';
 157     return $message;
 158 }
 159
 160 /**
 161  * Encrypt a message and return it in an XML-Encrypted document
 162  *
 163  * This function can encrypt any content, but it was written to provide a system
 164  * of encrypting XML-RPC request and response messages. The message will be
 165  * base64 encoded, so it does not need to be text - binary data should work.
 166  *
 167  * We compute the SHA1 digest of the message.
 168  * We compute a signature on that digest with our private key.
 169  * We link to the public key that can be used to verify our signature.
 170  * We base64 the message data.
 171  * We identify our wwwroot - this must match our certificate's CN
 172  *
 173  * The XML-RPC document will be parceled inside an XML-SIG document, which holds
 174  * the base64_encoded XML as an object, the SHA1 digest of that document, and a
 175  * signature of that document using the local private key. This signature will
 176  * uniquely identify the RPC document as having come from this server.
 177  *
 178  * See the {@Link http://www.w3.org/TR/xmlenc-core/ XML-ENC spec} at the W3c
 179  * site
 180  *
 181  * @param  string   $message              The data you want to sign
 182  * @param  string   $remote_certificate   Peer's certificate in PEM format
 183  * @return string                         An XML-ENC document
 184  */
 185 function mnet_encrypt_message($message, $remote_certificate) {
 186     global $MNET;
 187
 188     // Generate a key resource from the remote_certificate text string
 189     $publickey = openssl_get_publickey($remote_certificate);
 190
 191     if ( gettype($publickey) != 'resource' ) {
 192         // Remote certificate is faulty.
 193         return false;
 194     }
 195
 196     // Initialize vars
 197     $encryptedstring = '';
 198     $symmetric_keys = array();
 199
 200     //        passed by ref ->     &$encryptedstring &$symmetric_keys
 201     $bool = openssl_seal($message, $encryptedstring, $symmetric_keys, array($publickey));
 202     $message = $encryptedstring;
 203     $symmetrickey = array_pop($symmetric_keys);
 204
 205     $message = '<?xml version="1.0" encoding="iso-8859-1"?>
 206     <encryptedMessage>
 207         <EncryptedData Id="ED" xmlns="http://www.w3.org/2001/04/xmlenc#">
 208             <EncryptionMethod Algorithm="http://www.w3.org/2001/04/xmlenc#arcfour"/>
 209             <ds:KeyInfo xmlns:ds="http://www.w3.org/2000/09/xmldsig#">
 210                 <ds:RetrievalMethod URI="#EK" Type="http://www.w3.org/2001/04/xmlenc#EncryptedKey"/>
 211                 <ds:KeyName>XMLENC</ds:KeyName>
 212             </ds:KeyInfo>
 213             <CipherData>
 214                 <CipherValue>'.base64_encode($message).'</CipherValue>
 215             </CipherData>
 216         </EncryptedData>
 217         <EncryptedKey Id="EK" xmlns="http://www.w3.org/2001/04/xmlenc#">
 218             <EncryptionMethod Algorithm="http://www.w3.org/2001/04/xmlenc#rsa-1_5"/>
 219             <ds:KeyInfo xmlns:ds="http://www.w3.org/2000/09/xmldsig#">
 220                 <ds:KeyName>SSLKEY</ds:KeyName>
 221             </ds:KeyInfo>
 222             <CipherData>
 223                 <CipherValue>'.base64_encode($symmetrickey).'</CipherValue>
 224             </CipherData>
 225             <ReferenceList>
 226                 <DataReference URI="#ED"/>
 227             </ReferenceList>
 228             <CarriedKeyName>XMLENC</CarriedKeyName>
 229         </EncryptedKey>
 230         <wwwroot>'.$MNET->wwwroot.'</wwwroot>
 231     </encryptedMessage>';
 232     return $message;
 233 }
 234
 235 /**
 236  * Get your SSL keys from the database, or create them (if they don't exist yet)
 237  *
 238  * Get your SSL keys from the database, or (if they don't exist yet) call
 239  * mnet_generate_keypair to create them
 240  *
 241  * @param   string  $string     The text you want to sign
 242  * @return  string              The signature over that text
 243  */
 244 function mnet_get_keypair() {
 245     global $CFG;
 246     static $keypair = null;
 247     if (!is_null($keypair)) return $keypair;
 248     if ($result = get_field('config_plugins', 'value', 'plugin', 'mnet', 'name', 'openssl')) {
 249         $keypair               = explode('@@@@@@@@', $keypair);
 250         $keypair['privatekey'] = openssl_pkey_get_private($keypair['keypair_PEM']);
 251         $keypair['publickey']  = openssl_pkey_get_public($keypair['certificate']);
 252         return $keypair;
 253     } else {
 254         $keypair = mnet_generate_keypair();
 255         return $keypair;
 256     }
 257 }
 258
 259 /**
 260  * Generate public/private keys and store in the config table
 261  *
 262  * Use the distinguished name provided to create a CSR, and then sign that CSR
 263  * with the same credentials. Store the keypair you create in the config table.
 264  * If a distinguished name is not provided, create one using the fullname of
 265  * 'the course with ID 1' as your organization name, and your hostname (as
 266  * detailed in $CFG->wwwroot).
 267  *
 268  * @param   array  $dn  The distinguished name of the server
 269  * @return  string      The signature over that text
 270  */
 271 function mnet_generate_keypair($dn = null, $days=28) {
 272     global $CFG, $USER;
 273     $host = strtolower($CFG->wwwroot);
 274     $host = ereg_replace("^http(s)?://",'',$host);
 275     $break = strpos($host.'/' , '/');
 276     $host   = substr($host, 0, $break);
 277
 278     if ($result = get_record_select('course'," id ='".SITEID."' ")) {
 279         $organization = $result->fullname;
 280     } else {
 281         $organization = 'None';
 282     }
 283
 284     $keypair = array();
 285
 286     $country  = 'NZ';
 287     $province = 'Wellington';
 288     $locality = 'Wellington';
 289     $email    = $CFG->noreplyaddress;
 290
 291     if(!empty($USER->country)) {
 292         $country  = $USER->country;
 293     }
 294     if(!empty($USER->city)) {
 295         $province = $USER->city;
 296         $locality = $USER->city;
 297     }
 298     if(!empty($USER->email)) {
 299         $email    = $USER->email;
 300     }
 301
 302     if (is_null($dn)) {
 303         $dn = array(
 304            "countryName" => $country,
 305            "stateOrProvinceName" => $province,
 306            "localityName" => $locality,
 307            "organizationName" => $organization,
 308            "organizationalUnitName" => 'Moodle',
 309            "commonName" => $CFG->wwwroot,
 310            "emailAddress" => $email
 311         );
 312     }
 313
 314     // ensure we remove trailing slashes
 315     $dn["commonName"] = preg_replace(':/$:', '', $dn["commonName"]);
 316
 317     $new_key = openssl_pkey_new();
 318     $csr_rsc = openssl_csr_new($dn, $new_key, array('private_key_bits',2048));
 319     $selfSignedCert = openssl_csr_sign($csr_rsc, null, $new_key, $days);
 320     unset($csr_rsc); // Free up the resource
 321
 322     // We export our self-signed certificate to a string.
 323     openssl_x509_export($selfSignedCert, $keypair['certificate']);
 324     openssl_x509_free($selfSignedCert);
 325
 326     // Export your public/private key pair as a PEM encoded string. You
 327     // can protect it with an optional passphrase if you wish.
 328     $export = openssl_pkey_export($new_key, $keypair['keypair_PEM'] /* , $passphrase */);
 329     openssl_pkey_free($new_key);
 330     unset($new_key); // Free up the resource
 331
 332     return $keypair;
 333 }
 334
 335 /**
 336  * Check that an IP address falls within the given network/mask
 337  * ok for export
 338  *
 339  * @param  string   $address        Dotted quad
 340  * @param  string   $network        Dotted quad
 341  * @param  string   $mask           A number, e.g. 16, 24, 32
 342  * @return bool
 343  */
 344 function ip_in_range($address, $network, $mask) {
 345    $lnetwork  = ip2long($network);
 346    $laddress  = ip2long($address);
 347
 348    $binnet    = str_pad( decbin($lnetwork),32,"0","STR_PAD_LEFT" );
 349    $firstpart = substr($binnet,0,$mask);
 350
 351    $binip     = str_pad( decbin($laddress),32,"0","STR_PAD_LEFT" );
 352    $firstip   = substr($binip,0,$mask);
 353    return(strcmp($firstpart,$firstip)==0);
 354 }
 355
 356 /**
 357  * Check that a given function (or method) in an include file has been designated
 358  * ok for export
 359  *
 360  * @param  string   $includefile    The path to the include file
 361  * @param  string   $functionname   The name of the function (or method) to
 362  *                                  execute
 363  * @param  mixed    $class          A class name, or false if we're just testing
 364  *                                  a function
 365  * @return int                      Zero (RPC_OK) if all ok - appropriate
 366  *                                  constant otherwise
 367  */
 368 function mnet_permit_rpc_call($includefile, $functionname, $class=false) {
 369     global $CFG, $MNET_REMOTE_CLIENT;
 370
 371     if (file_exists($CFG->dirroot . $includefile)) {
 372         include_once $CFG->dirroot . $includefile;
 373         // $callprefix matches the rpc convention
 374         // of not having a leading slash
 375         $callprefix = preg_replace('!^/!', '', $includefile);
 376     } else {
 377         return RPC_NOSUCHFILE;
 378     }
 379
 380     if ($functionname != clean_param($functionname, PARAM_PATH)) {
 381         // Under attack?
 382         // Todo: Should really return a much more BROKEN! response
 383         return RPC_FORBIDDENMETHOD;
 384     }
 385
 386     $id_list = $MNET_REMOTE_CLIENT->id;
 387     if (!empty($CFG->mnet_all_hosts_id)) {
 388         $id_list .= ', '.$CFG->mnet_all_hosts_id;
 389     }
 390
 391     // TODO: change to left-join so we can disambiguate:
 392     // 1. method doesn't exist
 393     // 2. method exists but is prohibited
 394     $sql = "
 395         SELECT
 396             count(r.id)
 397         FROM
 398             {$CFG->prefix}mnet_host2service h2s,
 399             {$CFG->prefix}mnet_service2rpc s2r,
 400             {$CFG->prefix}mnet_rpc r
 401         WHERE
 402             h2s.serviceid = s2r.serviceid AND
 403             s2r.rpcid = r.id AND
 404             r.xmlrpc_path = '$callprefix/$functionname' AND
 405             h2s.hostid in ($id_list) AND
 406             h2s.publish = '1'";
 407
 408     $permissionobj = record_exists_sql($sql);
 409
 410     if ($permissionobj === false) {
 411         return RPC_FORBIDDENMETHOD;
 412     }
 413
 414     // WE'RE LOOKING AT A CLASS/METHOD
 415     if (false != $class) {
 416         if (!class_exists($class)) {
 417             // Generate error response - unable to locate class
 418             return RPC_NOSUCHCLASS;
 419         }
 420
 421         $object = new $class();
 422
 423         if (!method_exists($object, $functionname)) {
 424             // Generate error response - unable to locate method
 425             return RPC_NOSUCHMETHOD;
 426         }
 427
 428         if (!method_exists($object, 'mnet_publishes')) {
 429             // Generate error response - the class doesn't publish
 430             // *any* methods, because it doesn't have an mnet_publishes
 431             // method
 432             return RPC_FORBIDDENMETHOD;
 433         }
 434
 435         // Get the list of published services - initialise method array
 436         $servicelist = $object->mnet_publishes();
 437         $methodapproved = false;
 438
 439         // If the method is in the list of approved methods, set the
 440         // methodapproved flag to true and break
 441         foreach($servicelist as $service) {
 442             if (in_array($functionname, $service['methods'])) {
 443                 $methodapproved = true;
 444                 break;
 445             }
 446         }
 447
 448         if (!$methodapproved) {
 449             return RPC_FORBIDDENMETHOD;
 450         }
 451
 452         // Stash the object so we can call the method on it later
 453         $MNET_REMOTE_CLIENT->object_to_call($object);
 454     // WE'RE LOOKING AT A FUNCTION
 455     } else {
 456         if (!function_exists($functionname)) {
 457             // Generate error response - unable to locate function
 458             return RPC_NOSUCHFUNCTION;
 459         }
 460
 461     }
 462
 463     return RPC_OK;
 464 }
 465
 466 function mnet_update_sso_access_control($username, $mnet_host_id, $accessctrl) {
 467     $mnethost = get_record('mnet_host', 'id', $mnet_host_id);
 468     if ($aclrecord = get_record('mnet_sso_access_control', 'username', $username, 'mnet_host_id', $mnet_host_id)) {
 469         // update
 470         $aclrecord->accessctrl = $accessctrl;
 471         if (update_record('mnet_sso_access_control', $aclrecord)) {
 472             add_to_log(SITEID, 'admin/mnet', 'update', 'admin/mnet/access_control.php',
 473                     "SSO ACL: $access user '$username' from {$mnethost->name}");
 474         } else {
 475             error(get_string('failedaclwrite','mnet', $username));
 476             return false;
 477         }
 478     } else {
 479         // insert
 480         $aclrecord->username = $username;
 481         $aclrecord->accessctrl = $accessctrl;
 482         $aclrecord->mnet_host_id = $mnet_host_id;
 483         if ($id = insert_record('mnet_sso_access_control', $aclrecord)) {
 484             add_to_log(SITEID, 'admin/mnet', 'add', 'admin/mnet/access_control.php',
 485                     "SSO ACL: $access user '$username' from {$mnethost->name}");
 486         } else {
 487             error(get_string('failedaclwrite','mnet', $username));
 488             return false;
 489         }
 490     }
 491     return true;
 492 }
 493 ?>