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<?php
/**
* This class implements a generic IdP discovery service, for use in various IdP
* discovery service pages. This should reduce code duplication.
*
* Experimental support added for Extended IdP Metadata Discovery Protocol by Andreas 2008-08-28
* More information: http://rnd.feide.no/content/extended-identity-provider-discovery-service-protocol
*
* @author Olav Morken, UNINETT AS.
* @author Andreas Åkre Solberg <andreas@uninett.no>, UNINETT AS.
* @package simpleSAMLphp
* @version $Id$
*/
class SimpleSAML_XHTML_IdPDisco {
/**
* An instance of the configuration class.
*/
protected $config;
/**
* The identifier of this discovery service.
*
* @var string
*/
protected $instance;
/**
* An instance of the metadata handler, which will allow us to fetch metadata about IdPs.
*/
protected $metadata;
/**
* The users session.
*/
protected $session;
/**
* The metadata sets we find allowed entities in, in prioritized order.
*
* @var array
*/
protected $metadataSets;
/**
* The entity id of the SP which accesses this IdP discovery service.
*/
protected $spEntityId;
/**
* HTTP parameter from the request, indicating whether the discovery service
* can interact with the user or not.
*/
protected $isPassive;
/**
* The SP request to set the IdPentityID...
*/
protected $setIdPentityID = NULL;
/**
* The name of the query parameter which should contain the users choice of IdP.
* This option default to 'entityID' for Shibboleth compatibility.
*/
protected $returnIdParam;
/**
* The list of scoped idp's. The intersection between the metadata idpList
* and scopedIDPList (given as a $_GET IDPList[] parameter) is presented to
* the user. If the intersection is empty the metadata idpList is used.
*/
protected $scopedIDPList = array();
/**
* The URL the user should be redirected to after choosing an IdP.
*/
protected $returnURL;
/**
* Initializes this discovery service.
*
* The constructor does the parsing of the request. If this is an invalid request, it will
* throw an exception.
*
* @param array $metadataSets Array with metadata sets we find remote entities in.
* @param string $instance The name of this instance of the discovery service.
*/
public function __construct(array $metadataSets, $instance) {
assert('is_string($instance)');
/* Initialize standard classes. */
$this->config = SimpleSAML_Configuration::getInstance();
$this->metadata = SimpleSAML_Metadata_MetaDataStorageHandler::getMetadataHandler();
$this->session = SimpleSAML_Session::getInstance();
$this->instance = $instance;
$this->metadataSets = $metadataSets;
$this->log('Accessing discovery service.');
/* Standard discovery service parameters. */
if(!array_key_exists('entityID', $_GET)) {
throw new Exception('Missing parameter: entityID');
} else {
$this->spEntityId = $_GET['entityID'];
}
if(!array_key_exists('returnIDParam', $_GET)) {
$this->returnIdParam = 'entityID';
} else {
$this->returnIdParam = $_GET['returnIDParam'];
}
$this->log('returnIdParam initially set to [' . $this->returnIdParam . ']');
if(!array_key_exists('return', $_GET)) {
throw new Exception('Missing parameter: return');
} else {
$this->returnURL = $_GET['return'];
}
$this->isPassive = FALSE;
if (array_key_exists('isPassive', $_GET)) {
if ($_GET['isPassive'] === 'true') $this->isPassive = TRUE;
}
$this->log('isPassive initially set to [' . ($this->isPassive ? 'TRUE' : 'FALSE' ) . ']');
if (array_key_exists('IdPentityID', $_GET)) {
$this->setIdPentityID = $_GET['IdPentityID'];
} else {
$this->setIdPentityID = NULL;
}
if (array_key_exists('IDPList', $_REQUEST)) {
$this->scopedIDPList = $_REQUEST['IDPList'];
}
}
/**
* Log a message.
*
* This is an helper function for logging messages. It will prefix the messages with our
* discovery service type.
*
* @param $message The message which should be logged.
*/
protected function log($message) {
SimpleSAML_Logger::info('idpDisco.' . $this->instance . ': ' . $message);
}
/**
* Retrieve cookie with the given name.
*
* This function will retrieve a cookie with the given name for the current discovery
* service type.
*
* @param $name The name of the cookie.
* @return The value of the cookie with the given name, or NULL if no cookie with that name exists.
*/
protected function getCookie($name) {
$prefixedName = 'idpdisco_' . $this->instance . '_' . $name;
if(array_key_exists($prefixedName, $_COOKIE)) {
return $_COOKIE[$prefixedName];
} else {
return NULL;
}
}
/**
* Save cookie with the given name and value.
*
* This function will save a cookie with the given name and value for the current discovery
* service type.
*
* @param $name The name of the cookie.
* @param $value The value of the cookie.
*/
protected function setCookie($name, $value) {
$prefixedName = 'idpdisco_' . $this->instance . '_' . $name;
/* We save the cookies for 90 days. */
$saveUntil = time() + 60*60*24*90;
/* The base path for cookies. This should be the installation directory for simpleSAMLphp. */
$cookiePath = '/' . $this->config->getBaseUrl();
setcookie($prefixedName, $value, $saveUntil, $cookiePath);
}
/**
* Validates the given IdP entity id.
*
* Takes a string with the IdP entity id, and returns the entity id if it is valid, or
* NULL if not.
*
* @param $idp The entity id we want to validate. This can be NULL, in which case we will return NULL.
* @return The entity id if it is valid, NULL if not.
*/
protected function validateIdP($idp) {
if($idp === NULL) {
return NULL;
}
if(!$this->config->getBoolean('idpdisco.validate', TRUE)) {
return $idp;
}
foreach ($this->metadataSets AS $metadataSet) {
try {
$this->metadata->getMetaData($idp, $metadataSet);
return $idp;
} catch(Exception $e) { }
}
$this->log('Unable to validate IdP entity id [' . $idp . '].');
/* The entity id wasn't valid. */
return NULL;
}
/**
* Retrieve the users choice of IdP.
*
* This function finds out which IdP the user has manually chosen, if any.
*
* @return The entity id of the IdP the user has chosen, or NULL if the user has made no choice.
*/
protected function getSelectedIdP() {
/* Parameter set from the Extended IdP Metadata Discovery Service Protocol,
* indicating that the user prefers this IdP.
*/
if ($this->setIdPentityID) {
return $this->validateIdP($this->setIdPentityID);
}
/* User has clicked on a link, or selected the IdP from a dropdown list. */
if(array_key_exists('idpentityid', $_GET)) {
return $this->validateIdP($_GET['idpentityid']);
}
/* Search for the IdP selection from the form used by the links view.
* This form uses a name which equals idp_<entityid>, so we search for that.
*
* Unfortunately, php replaces periods in the name with underscores, and there
* is no reliable way to get them back. Therefore we do some quick and dirty
* parsing of the query string.
*/
$qstr = $_SERVER['QUERY_STRING'];
$matches = array();
if(preg_match('/(?:^|&)idp_([^=]+)=/', $qstr, $matches)) {
return $this->validateIdP(urldecode($matches[1]));
}
/* No IdP chosen. */
return NULL;
}
/**
* Retrieve the users saved choice of IdP.
*
* @return The entity id of the IdP the user has saved, or NULL if the user hasn't saved any choice.
*/
protected function getSavedIdP() {
if(!$this->config->getBoolean('idpdisco.enableremember', FALSE)) {
/* Saving of IdP choices is disabled. */
return NULL;
}
if($this->getCookie('remember') === '1') {
$this->log('Return previously saved IdP because of remember cookie set to 1');
return $this->getPreviousIdP();
}
if( $this->isPassive) {
$this->log('Return previously saved IdP because of isPassive');
return $this->getPreviousIdP();
}
return NULL;
}
/**
* Retrieve the previous IdP the user used.
*
* @return The entity id of the previous IdP the user used, or NULL if this is the first time.
*/
protected function getPreviousIdP() {
return $this->validateIdP($this->getCookie('lastidp'));
}
/**
* Retrieve a recommended IdP based on the IP address of the client.
*
* @return string|NULL The entity ID of the IdP if one is found, or NULL if not.
*/
protected function getFromCIDRhint() {
foreach ($this->metadataSets as $metadataSet) {
$idp = $this->metadata->getPreferredEntityIdFromCIDRhint($metadataSet, $_SERVER['REMOTE_ADDR']);
if (!empty($idp)) {
return $idp;
}
}
return NULL;
}
/**
* Try to determine which IdP the user should most likely use.
*
* This function will first look at the previous IdP the user has chosen. If the user
* hasn't chosen an IdP before, it will look at the IP address.
*
* @return The entity id of the IdP the user should most likely use.
*/
protected function getRecommendedIdP() {
$idp = $this->getPreviousIdP();
if($idp !== NULL) {
$this->log('Preferred IdP from previous use [' . $idp . '].');
return $idp;
}
$idp = $this->getFromCIDRhint();
if(!empty($idp)) {
$this->log('Preferred IdP from CIDR hint [' . $idp . '].');
return $idp;
}
return NULL;
}
/**
* Save the current IdP choice to a cookie.
*
* @param string $idp The entityID of the IdP.
*/
protected function setPreviousIdP($idp) {
assert('is_string($idp)');
$this->log('Choice made [' . $idp . '] Setting cookie.');
$this->setCookie('lastidp', $idp);
}
/**
* Determine whether the choice of IdP should be saved.
*
* @return TRUE if the choice should be saved, FALSE if not.
*/
protected function saveIdP() {
if(!$this->config->getBoolean('idpdisco.enableremember', FALSE)) {
/* Saving of IdP choices is disabled. */
return FALSE;
}
if(array_key_exists('remember', $_GET)) {
return TRUE;
}
}
/**
* Determine which IdP the user should go to, if any.
*
* @return The entity id of the IdP the user should be sent to, or NULL if the user
* should choose.
*/
protected function getTargetIdP() {
/* First, check if the user has chosen an IdP. */
$idp = $this->getSelectedIdP();
if($idp !== NULL) {
/* The user selected this IdP. Save the choice in a cookie. */
$this->setPreviousIdP($idp);
if($this->saveIdP()) {
$this->setCookie('remember', 1);
} else {
$this->setCookie('remember', 0);
}
return $idp;
}
$this->log('getSelectedIdP() returned NULL');
/* Check if the user has saved an choice earlier. */
$idp = $this->getSavedIdP();
if($idp !== NULL) {
$this->log('Using saved choice [' . $idp . '].');
return $idp;
}
/* The user has made no choice. */
return NULL;
}
/**
* Retrieve the list of IdPs which are stored in the metadata.
*
* @return array Array with entityid=>metadata mappings.
*/
protected function getIdPList() {
$idpList = array();
foreach ($this->metadataSets AS $metadataSet) {
$newList = $this->metadata->getList($metadataSet);
/*
* Note that we merge the entities in reverse order. This ensuers
* that it is the entity in the first metadata set that "wins" if
* two metadata sets have the same entity.
*/
$idpList = array_merge($newList, $idpList);
}
return $idpList;
}
/**
* Return the list of scoped idp
*
* @return array Array of idp entities
*/
protected function getScopedIDPList() {
return $this->scopedIDPList;
}
/**
* Handles a request to this discovery service.
*
* The IdP disco parameters should be set before calling this function.
*/
public function handleRequest() {
$idp = $this->getTargetIdp();
if($idp !== NULL) {
$extDiscoveryStorage = $this->config->getString('idpdisco.extDiscoveryStorage', NULL);
if ($extDiscoveryStorage !== NULL) {
$this->log('Choice made [' . $idp . '] (Forwarding to external discovery storage)');
SimpleSAML_Utilities::redirect($extDiscoveryStorage, array(
// $this->returnIdParam => $idp,
'entityID' => $this->spEntityId,
'IdPentityID' => $idp,
'returnIDParam' => $this->returnIdParam,
'isPassive' => 'true',
'return' => $this->returnURL
));
} else {
$this->log('Choice made [' . $idp . '] (Redirecting the user back. returnIDParam=' . $this->returnIdParam . ')');
SimpleSAML_Utilities::redirect($this->returnURL, array($this->returnIdParam => $idp));
}
return;
}
if ($this->isPassive) {
$this->log('Choice not made. (Redirecting the user back without answer)');
SimpleSAML_Utilities::redirect($this->returnURL);
return;
}
/* No choice made. Show discovery service page. */
$idpList = $this->getIdPList();
$preferredIdP = $this->getRecommendedIdP();
$idpintersection = array_intersect(array_keys($idpList), $this->getScopedIDPList());
if (sizeof($idpintersection) > 0) {
$idpList = array_intersect_key($idpList, array_fill_keys($idpintersection, NULL));
}
$idpintersection = array_values($idpintersection);
if(sizeof($idpintersection) == 1) {
$this->log('Choice made [' . $idpintersection[0] . '] (Redirecting the user back. returnIDParam=' . $this->returnIdParam . ')');
SimpleSAML_Utilities::redirect($this->returnURL, array($this->returnIdParam => $idpintersection[0]));
}
/*
* Make use of an XHTML template to present the select IdP choice to the user.
* Currently the supported options is either a drop down menu or a list view.
*/
switch($this->config->getString('idpdisco.layout', 'links')) {
case 'dropdown':
$templateFile = 'selectidp-dropdown.php';
break;
case 'links':
$templateFile = 'selectidp-links.php';
break;
default:
throw new Exception('Invalid value for the \'idpdisco.layout\' option.');
}
$t = new SimpleSAML_XHTML_Template($this->config, $templateFile, 'disco');
$t->data['idplist'] = $idpList;
$t->data['preferredidp'] = $preferredIdP;
$t->data['return'] = $this->returnURL;
$t->data['returnIDParam'] = $this->returnIdParam;
$t->data['entityID'] = $this->spEntityId;
$t->data['urlpattern'] = htmlspecialchars(SimpleSAML_Utilities::selfURLNoQuery());
$t->data['rememberenabled'] = $this->config->getBoolean('idpdisco.enableremember', FALSE);
$t->show();
}
}
?>
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