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