mnet/lib.php

   1 <?php // $Id$
   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, $application=null) {
  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 $key;
  55     }
  56
  57     if (empty($application)) {
  58         $application = get_record('mnet_application', 'name', 'moodle');
  59     }
  60
  61     $rq = xmlrpc_encode_request('system/keyswap', array($CFG->wwwroot, $MNET->public_key, $application->name), array("encoding" => "utf-8"));
  62     $ch = curl_init($uri . $application->xmlrpc_server_url);
  63
  64     curl_setopt($ch, CURLOPT_TIMEOUT, 60);
  65     curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
  66     curl_setopt($ch, CURLOPT_POST, true);
  67     curl_setopt($ch, CURLOPT_USERAGENT, 'Moodle');
  68     curl_setopt($ch, CURLOPT_POSTFIELDS, $rq);
  69     curl_setopt($ch, CURLOPT_HTTPHEADER, array("Content-Type: text/xml charset=UTF-8"));
  70     curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
  71     curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
  72
  73     $res = xmlrpc_decode(curl_exec($ch));
  74     curl_close($ch);
  75
  76     if (!is_array($res)) { // ! error
  77         $public_certificate = $res;
  78         $credentials=array();
  79         if (strlen(trim($public_certificate))) {
  80             $credentials = openssl_x509_parse($public_certificate);
  81             $host = $credentials['subject']['CN'];
  82             if (strpos($uri, $host) !== false) {
  83                 mnet_set_public_key($uri, $public_certificate);
  84                 return $public_certificate;
  85             }
  86         }
  87     }
  88     return false;
  89 }
  90
  91 /**
  92  * Store a URI's public key in a static variable, or retrieve the key for a URI
  93  *
  94  * @param  string  $uri  The URI of a file on the remote computer, including its
  95  *                       https:// prefix
  96  * @param  mixed   $key  A public key to store in the array OR null. If the key
  97  *                       is null, the function will return the previously stored
  98  *                       key for the supplied URI, should it exist.
  99  * @return mixed         A public key OR true/false.
 100  */
 101 function mnet_set_public_key($uri, $key = null) {
 102     static $keyarray = array();
 103     if (isset($keyarray[$uri]) && empty($key)) {
 104         return $keyarray[$uri];
 105     } elseif (!empty($key)) {
 106         $keyarray[$uri] = $key;
 107         return true;
 108     }
 109     return false;
 110 }
 111
 112 /**
 113  * Sign a message and return it in an XML-Signature document
 114  *
 115  * This function can sign any content, but it was written to provide a system of
 116  * signing XML-RPC request and response messages. The message will be base64
 117  * encoded, so it does not need to be text.
 118  *
 119  * We compute the SHA1 digest of the message.
 120  * We compute a signature on that digest with our private key.
 121  * We link to the public key that can be used to verify our signature.
 122  * We base64 the message data.
 123  * We identify our wwwroot - this must match our certificate's CN
 124  *
 125  * The XML-RPC document will be parceled inside an XML-SIG document, which holds
 126  * the base64_encoded XML as an object, the SHA1 digest of that document, and a
 127  * signature of that document using the local private key. This signature will
 128  * uniquely identify the RPC document as having come from this server.
 129  *
 130  * See the {@Link http://www.w3.org/TR/xmldsig-core/ XML-DSig spec} at the W3c
 131  * site
 132  *
 133  * @param  string   $message              The data you want to sign
 134  * @param  resource $privatekey           The private key to sign the response with
 135  * @return string                         An XML-DSig document
 136  */
 137 function mnet_sign_message($message, $privatekey = null) {
 138     global $CFG, $MNET;
 139     $digest = sha1($message);
 140
 141     // If the user hasn't supplied a private key (for example, one of our older,
 142     //  expired private keys, we get the current default private key and use that.
 143     if ($privatekey == null) {
 144         $privatekey = $MNET->get_private_key();
 145     }
 146
 147     // The '$sig' value below is returned by reference.
 148     // We initialize it first to stop my IDE from complaining.
 149     $sig  = '';
 150     $bool = openssl_sign($message, $sig, $privatekey); // TODO: On failure?
 151
 152     $message = '<?xml version="1.0" encoding="iso-8859-1"?>
 153     <signedMessage>
 154         <Signature Id="MoodleSignature" xmlns="http://www.w3.org/2000/09/xmldsig#">
 155             <SignedInfo>
 156                 <CanonicalizationMethod Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315"/>
 157                 <SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#dsa-sha1"/>
 158                 <Reference URI="#XMLRPC-MSG">
 159                     <DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/>
 160                     <DigestValue>'.$digest.'</DigestValue>
 161                 </Reference>
 162             </SignedInfo>
 163             <SignatureValue>'.base64_encode($sig).'</SignatureValue>
 164             <KeyInfo>
 165                 <RetrievalMethod URI="'.$CFG->wwwroot.'/mnet/publickey.php"/>
 166             </KeyInfo>
 167         </Signature>
 168         <object ID="XMLRPC-MSG">'.base64_encode($message).'</object>
 169         <wwwroot>'.$MNET->wwwroot.'</wwwroot>
 170         <timestamp>'.time().'</timestamp>
 171     </signedMessage>';
 172     return $message;
 173 }
 174
 175 /**
 176  * Encrypt a message and return it in an XML-Encrypted document
 177  *
 178  * This function can encrypt any content, but it was written to provide a system
 179  * of encrypting XML-RPC request and response messages. The message will be
 180  * base64 encoded, so it does not need to be text - binary data should work.
 181  *
 182  * We compute the SHA1 digest of the message.
 183  * We compute a signature on that digest with our private key.
 184  * We link to the public key that can be used to verify our signature.
 185  * We base64 the message data.
 186  * We identify our wwwroot - this must match our certificate's CN
 187  *
 188  * The XML-RPC document will be parceled inside an XML-SIG document, which holds
 189  * the base64_encoded XML as an object, the SHA1 digest of that document, and a
 190  * signature of that document using the local private key. This signature will
 191  * uniquely identify the RPC document as having come from this server.
 192  *
 193  * See the {@Link http://www.w3.org/TR/xmlenc-core/ XML-ENC spec} at the W3c
 194  * site
 195  *
 196  * @param  string   $message              The data you want to sign
 197  * @param  string   $remote_certificate   Peer's certificate in PEM format
 198  * @return string                         An XML-ENC document
 199  */
 200 function mnet_encrypt_message($message, $remote_certificate) {
 201     global $MNET;
 202
 203     // Generate a key resource from the remote_certificate text string
 204     $publickey = openssl_get_publickey($remote_certificate);
 205
 206     if ( gettype($publickey) != 'resource' ) {
 207         // Remote certificate is faulty.
 208         return false;
 209     }
 210
 211     // Initialize vars
 212     $encryptedstring = '';
 213     $symmetric_keys = array();
 214
 215     //        passed by ref ->     &$encryptedstring &$symmetric_keys
 216     $bool = openssl_seal($message, $encryptedstring, $symmetric_keys, array($publickey));
 217     $message = $encryptedstring;
 218     $symmetrickey = array_pop($symmetric_keys);
 219
 220     $message = '<?xml version="1.0" encoding="iso-8859-1"?>
 221     <encryptedMessage>
 222         <EncryptedData Id="ED" xmlns="http://www.w3.org/2001/04/xmlenc#">
 223             <EncryptionMethod Algorithm="http://www.w3.org/2001/04/xmlenc#arcfour"/>
 224             <ds:KeyInfo xmlns:ds="http://www.w3.org/2000/09/xmldsig#">
 225                 <ds:RetrievalMethod URI="#EK" Type="http://www.w3.org/2001/04/xmlenc#EncryptedKey"/>
 226                 <ds:KeyName>XMLENC</ds:KeyName>
 227             </ds:KeyInfo>
 228             <CipherData>
 229                 <CipherValue>'.base64_encode($message).'</CipherValue>
 230             </CipherData>
 231         </EncryptedData>
 232         <EncryptedKey Id="EK" xmlns="http://www.w3.org/2001/04/xmlenc#">
 233             <EncryptionMethod Algorithm="http://www.w3.org/2001/04/xmlenc#rsa-1_5"/>
 234             <ds:KeyInfo xmlns:ds="http://www.w3.org/2000/09/xmldsig#">
 235                 <ds:KeyName>SSLKEY</ds:KeyName>
 236             </ds:KeyInfo>
 237             <CipherData>
 238                 <CipherValue>'.base64_encode($symmetrickey).'</CipherValue>
 239             </CipherData>
 240             <ReferenceList>
 241                 <DataReference URI="#ED"/>
 242             </ReferenceList>
 243             <CarriedKeyName>XMLENC</CarriedKeyName>
 244         </EncryptedKey>
 245         <wwwroot>'.$MNET->wwwroot.'</wwwroot>
 246     </encryptedMessage>';
 247     return $message;
 248 }
 249
 250 /**
 251  * Get your SSL keys from the database, or create them (if they don't exist yet)
 252  *
 253  * Get your SSL keys from the database, or (if they don't exist yet) call
 254  * mnet_generate_keypair to create them
 255  *
 256  * @param   string  $string     The text you want to sign
 257  * @return  string              The signature over that text
 258  */
 259 function mnet_get_keypair() {
 260     global $CFG;
 261     static $keypair = null;
 262     if (!is_null($keypair)) return $keypair;
 263     if ($result = get_field('config_plugins', 'value', 'plugin', 'mnet', 'name', 'openssl')) {
 264         list($keypair['certificate'], $keypair['keypair_PEM']) = explode('@@@@@@@@', $result);
 265         $keypair['privatekey'] = openssl_pkey_get_private($keypair['keypair_PEM']);
 266         $keypair['publickey']  = openssl_pkey_get_public($keypair['certificate']);
 267         return $keypair;
 268     } else {
 269         $keypair = mnet_generate_keypair();
 270         return $keypair;
 271     }
 272 }
 273
 274 /**
 275  * Generate public/private keys and store in the config table
 276  *
 277  * Use the distinguished name provided to create a CSR, and then sign that CSR
 278  * with the same credentials. Store the keypair you create in the config table.
 279  * If a distinguished name is not provided, create one using the fullname of
 280  * 'the course with ID 1' as your organization name, and your hostname (as
 281  * detailed in $CFG->wwwroot).
 282  *
 283  * @param   array  $dn  The distinguished name of the server
 284  * @return  string      The signature over that text
 285  */
 286 function mnet_generate_keypair($dn = null, $days=28) {
 287     global $CFG, $USER;
 288     $host = strtolower($CFG->wwwroot);
 289     $host = ereg_replace("^http(s)?://",'',$host);
 290     $break = strpos($host.'/' , '/');
 291     $host   = substr($host, 0, $break);
 292
 293     if ($result = get_record_select('course'," id ='".SITEID."' ")) {
 294         $organization = $result->fullname;
 295     } else {
 296         $organization = 'None';
 297     }
 298
 299     $keypair = array();
 300
 301     $country  = 'NZ';
 302     $province = 'Wellington';
 303     $locality = 'Wellington';
 304     $email    = $CFG->noreplyaddress;
 305
 306     if(!empty($USER->country)) {
 307         $country  = $USER->country;
 308     }
 309     if(!empty($USER->city)) {
 310         $province = $USER->city;
 311         $locality = $USER->city;
 312     }
 313     if(!empty($USER->email)) {
 314         $email    = $USER->email;
 315     }
 316
 317     if (is_null($dn)) {
 318         $dn = array(
 319            "countryName" => $country,
 320            "stateOrProvinceName" => $province,
 321            "localityName" => $locality,
 322            "organizationName" => $organization,
 323            "organizationalUnitName" => 'Moodle',
 324            "commonName" => $CFG->wwwroot,
 325            "emailAddress" => $email
 326         );
 327     }
 328
 329     // ensure we remove trailing slashes
 330     $dn["commonName"] = preg_replace(':/$:', '', $dn["commonName"]);
 331
 332     $new_key = openssl_pkey_new();
 333     $csr_rsc = openssl_csr_new($dn, $new_key, array('private_key_bits',2048));
 334     $selfSignedCert = openssl_csr_sign($csr_rsc, null, $new_key, $days);
 335     unset($csr_rsc); // Free up the resource
 336
 337     // We export our self-signed certificate to a string.
 338     openssl_x509_export($selfSignedCert, $keypair['certificate']);
 339     openssl_x509_free($selfSignedCert);
 340
 341     // Export your public/private key pair as a PEM encoded string. You
 342     // can protect it with an optional passphrase if you wish.
 343     $export = openssl_pkey_export($new_key, $keypair['keypair_PEM'] /* , $passphrase */);
 344     openssl_pkey_free($new_key);
 345     unset($new_key); // Free up the resource
 346
 347     return $keypair;
 348 }
 349
 350 /**
 351  * Check that an IP address falls within the given network/mask
 352  * ok for export
 353  *
 354  * @param  string   $address        Dotted quad
 355  * @param  string   $network        Dotted quad
 356  * @param  string   $mask           A number, e.g. 16, 24, 32
 357  * @return bool
 358  */
 359 function ip_in_range($address, $network, $mask) {
 360    $lnetwork  = ip2long($network);
 361    $laddress  = ip2long($address);
 362
 363    $binnet    = str_pad( decbin($lnetwork),32,"0","STR_PAD_LEFT" );
 364    $firstpart = substr($binnet,0,$mask);
 365
 366    $binip     = str_pad( decbin($laddress),32,"0","STR_PAD_LEFT" );
 367    $firstip   = substr($binip,0,$mask);
 368    return(strcmp($firstpart,$firstip)==0);
 369 }
 370
 371 /**
 372  * Check that a given function (or method) in an include file has been designated
 373  * ok for export
 374  *
 375  * @param  string   $includefile    The path to the include file
 376  * @param  string   $functionname   The name of the function (or method) to
 377  *                                  execute
 378  * @param  mixed    $class          A class name, or false if we're just testing
 379  *                                  a function
 380  * @return int                      Zero (RPC_OK) if all ok - appropriate
 381  *                                  constant otherwise
 382  */
 383 function mnet_permit_rpc_call($includefile, $functionname, $class=false) {
 384     global $CFG, $MNET_REMOTE_CLIENT;
 385
 386     if (file_exists($CFG->dirroot . $includefile)) {
 387         include_once $CFG->dirroot . $includefile;
 388         // $callprefix matches the rpc convention
 389         // of not having a leading slash
 390         $callprefix = preg_replace('!^/!', '', $includefile);
 391     } else {
 392         return RPC_NOSUCHFILE;
 393     }
 394
 395     if ($functionname != clean_param($functionname, PARAM_PATH)) {
 396         // Under attack?
 397         // Todo: Should really return a much more BROKEN! response
 398         return RPC_FORBIDDENMETHOD;
 399     }
 400
 401     $id_list = $MNET_REMOTE_CLIENT->id;
 402     if (!empty($CFG->mnet_all_hosts_id)) {
 403         $id_list .= ', '.$CFG->mnet_all_hosts_id;
 404     }
 405
 406     // TODO: change to left-join so we can disambiguate:
 407     // 1. method doesn't exist
 408     // 2. method exists but is prohibited
 409     $sql = "
 410         SELECT
 411             count(r.id)
 412         FROM
 413             {$CFG->prefix}mnet_host2service h2s,
 414             {$CFG->prefix}mnet_service2rpc s2r,
 415             {$CFG->prefix}mnet_rpc r
 416         WHERE
 417             h2s.serviceid = s2r.serviceid AND
 418             s2r.rpcid = r.id AND
 419             r.xmlrpc_path = '$callprefix/$functionname' AND
 420             h2s.hostid in ($id_list) AND
 421             h2s.publish = '1'";
 422
 423     $permissionobj = record_exists_sql($sql);
 424
 425     if ($permissionobj === false && 'dangerous' != $CFG->mnet_dispatcher_mode) {
 426         return RPC_FORBIDDENMETHOD;
 427     }
 428
 429     // WE'RE LOOKING AT A CLASS/METHOD
 430     if (false != $class) {
 431         if (!class_exists($class)) {
 432             // Generate error response - unable to locate class
 433             return RPC_NOSUCHCLASS;
 434         }
 435
 436         $object = new $class();
 437
 438         if (!method_exists($object, $functionname)) {
 439             // Generate error response - unable to locate method
 440             return RPC_NOSUCHMETHOD;
 441         }
 442
 443         if (!method_exists($object, 'mnet_publishes')) {
 444             // Generate error response - the class doesn't publish
 445             // *any* methods, because it doesn't have an mnet_publishes
 446             // method
 447             return RPC_FORBIDDENMETHOD;
 448         }
 449
 450         // Get the list of published services - initialise method array
 451         $servicelist = $object->mnet_publishes();
 452         $methodapproved = false;
 453
 454         // If the method is in the list of approved methods, set the
 455         // methodapproved flag to true and break
 456         foreach($servicelist as $service) {
 457             if (in_array($functionname, $service['methods'])) {
 458                 $methodapproved = true;
 459                 break;
 460             }
 461         }
 462
 463         if (!$methodapproved) {
 464             return RPC_FORBIDDENMETHOD;
 465         }
 466
 467         // Stash the object so we can call the method on it later
 468         $MNET_REMOTE_CLIENT->object_to_call($object);
 469     // WE'RE LOOKING AT A FUNCTION
 470     } else {
 471         if (!function_exists($functionname)) {
 472             // Generate error response - unable to locate function
 473             return RPC_NOSUCHFUNCTION;
 474         }
 475
 476     }
 477
 478     return RPC_OK;
 479 }
 480
 481 function mnet_update_sso_access_control($username, $mnet_host_id, $accessctrl) {
 482     $mnethost = get_record('mnet_host', 'id', $mnet_host_id);
 483     if ($aclrecord = get_record('mnet_sso_access_control', 'username', $username, 'mnet_host_id', $mnet_host_id)) {
 484         // update
 485         $aclrecord->accessctrl = $accessctrl;
 486         if (update_record('mnet_sso_access_control', $aclrecord)) {
 487             add_to_log(SITEID, 'admin/mnet', 'update', 'admin/mnet/access_control.php',
 488                     "SSO ACL: $accessctrl user '$username' from {$mnethost->name}");
 489         } else {
 490             print_error('failedaclwrite', 'mnet', '', $username);
 491             return false;
 492         }
 493     } else {
 494         // insert
 495         $aclrecord->username = $username;
 496         $aclrecord->accessctrl = $accessctrl;
 497         $aclrecord->mnet_host_id = $mnet_host_id;
 498         if ($id = insert_record('mnet_sso_access_control', $aclrecord)) {
 499             add_to_log(SITEID, 'admin/mnet', 'add', 'admin/mnet/access_control.php',
 500                     "SSO ACL: $accessctrl user '$username' from {$mnethost->name}");
 501         } else {
 502             print_error('failedaclwrite', 'mnet', '', $username);
 503             return false;
 504         }
 505     }
 506     return true;
 507 }
 508 ?>