Viewing file:  Negotiate.php (10.33 KB) -rwxrwxr-x
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<?php
/**
* The Negotiate module. Allows for password-less, secure login by
* Kerberos and Negotiate.
*
* @author Mathias Meisfjordskar, University of Oslo.
* <mathias.meisfjordskar@usit.uio.no>
* @package simpleSAMLphp
* @version $Id$
*/
class sspmod_negotiate_Auth_Source_Negotiate extends SimpleSAML_Auth_Source {
// Constants used in the module
const STAGEID = 'sspmod_negotiate_Auth_Source_Negotiate.StageId';
private $config;
protected $ldap = NULL;
/**
* Constructor for this authentication source.
*
* @param array $info Information about this authentication source.
* @param array $config Configuration.
*/
public function __construct($info, $config) {
assert('is_array($info)');
assert('is_array($config)');
if(!extension_loaded('krb5'))
throw new Exception('KRB5 Extension not installed');
// Call the parent constructor first, as required by the interface.
parent::__construct($info, $config);
$config = SimpleSAML_Configuration::loadFromArray($config);;
$this->backend = $config->getString('fallback');
$this->hostname = $config->getString('hostname');
$this->enableTLS = $config->getBoolean('enable_tls', FALSE);
$this->debugLDAP = $config->getBoolean('debugLDAP', FALSE);
$this->timeout = $config->getValue('timeout', 30);
$this->keytab = $config->getString('keytab');
$this->base = $config->getString('base');
$this->attr = $config->getString('attr', 'uid');
$this->subnet = $config->getArray('subnet', NULL);
$this->admin_user = $config->getString('adminUser', NULL);
$this->admin_pw = $config->getString('adminPassword', NULL);
}
/**
* The inner workings of the module.
*
* Checks to see if client is in the defined subnets (if
* defined in config). Sends the client a 401 Negotiate and
* responds to the result. If the client fails to provide a
* proper Kerberos ticket, the login process is handed over to
* the 'fallback' module defined in the config.
*
* LDAP is used as a user metadata source.
*
* @param array &$state Information about the current authentication.
*/
public function authenticate(&$state) {
assert('is_array($state)');
// Set the default backend to config
$state['LogoutState'] = array(
'negotiate:backend' => $this->backend,
);
$state['negotiate:authId'] = $this->authId;
// Check for disabled SPs. The disable flag is store in the SP
// metadata.
if (array_key_exists('SPMetadata', $state) and $this->spDisabledInMetadata($state['SPMetadata']))
$this->fallBack($state);
// Go straight to fallback if Negotiate is disabled or if you are
// sent back to the IdP directly from the SP after having logged out
$session = SimpleSAML_Session::getInstance();
$disabled = $session->getData('negotiate:disable', 'session');
if ($disabled or
(!empty($_COOKIE['NEGOTIATE_AUTOLOGIN_DISABLE_PERMANENT']) and
$_COOKIE['NEGOTIATE_AUTOLOGIN_DISABLE_PERMANENT'] == 'True')) {
SimpleSAML_Logger::debug('Negotiate - session disabled. falling back');
$this->fallBack($state);
// Never executed
assert('FALSE');
}
$mask = $this->checkMask();
if (!$mask) {
$this->fallBack($state);
// Never executed
assert('FALSE');
}
SimpleSAML_Logger::debug('Negotiate - authenticate(): looking for Negotate');
if (!empty($_SERVER['HTTP_AUTHORIZATION'])) {
SimpleSAML_Logger::debug('Negotiate - authenticate(): Negotate found');
$this->ldap = new SimpleSAML_Auth_LDAP($this->hostname, $this->enableTLS, $this->debugLDAP, $this->timeout);
list($mech, $data) = explode(' ', $_SERVER['HTTP_AUTHORIZATION'],2);
if(strtolower($mech) == 'basic')
SimpleSAML_Logger::debug('Negotiate - authenticate(): Basic found. Skipping.');
else if(strtolower($mech) != 'negotiate')
SimpleSAML_Logger::debug('Negotiate - authenticate(): No "Negotiate" found. Skipping.');
$auth = new KRB5NegotiateAuth($this->keytab);
// Atempt Kerberos authentication
try {
$reply = $auth->doAuthentication();
} catch (Exception $e) {
SimpleSAML_Logger::error('Negotiate - authenticate(): doAuthentication() exception: '. $e->getMessage());
$reply = NULL;
}
if($reply) {
// Success. Krb TGS recieved.
$user = $auth->getAuthenticatedUser();
SimpleSAML_Logger::info('Negotiate - authenticate(): '. $user . ' authenticated.');
$lookup = $this->lookupUserData($user);
if ($lookup) {
$state['Attributes'] = $lookup;
// Override the backend so logout will know what to look for.
$state['LogoutState'] = array(
'negotiate:backend' => NULL,
);
SimpleSAML_Logger::info('Negotiate - authenticate(): '. $user . ' authorized.');
SimpleSAML_Auth_Source::completeAuth($state);
// Never reached.
assert('FALSE');
}
} else {
// Some error in the recieved ticket. Expired?
SimpleSAML_Logger::info('Negotiate - authenticate(): Kerberos authN failed. Skipping.');
}
} else {
// No auth token. Send it.
SimpleSAML_Logger::debug('Negotiate - authenticate(): Sending Negotiate.');
// Save the $state array, so that we can restore if after a redirect
SimpleSAML_Logger::debug('Negotiate - fallback: '.$state['LogoutState']['negotiate:backend']);
$id = SimpleSAML_Auth_State::saveState($state, self::STAGEID);
$params = array('AuthState' => $id);
$this->sendNegotiate($params);
exit;
}
SimpleSAML_Logger::info('Negotiate - authenticate(): Client failed Negotiate. Falling back');
$this->fallBack($state);
/* The previous function never returns, so this code is never
executed */
assert('FALSE');
}
public function spDisabledInMetadata($spMetadata) {
if (array_key_exists('negotiate:disable', $spMetadata)) {
if ($spMetadata['negotiate:disable'] == TRUE) {
SimpleSAML_Logger::debug('Negotiate - SP disabled. falling back');
return True;
// Never executed
assert('FALSE');
} else {
SimpleSAML_Logger::debug('Negotiate - SP disable flag found but set to FALSE');
}
} else {
SimpleSAML_Logger::debug('Negotiate - SP disable flag not found');
}
return False;
}
/**
* checkMask() looks up the subnet config option and verifies
* that the client is within that range.
*
* Will return TRUE if no subnet option is configured.
*
* @return boolean
*/
public function checkMask() {
// No subnet means all clients are accepted.
if ($this->subnet === NULL)
return TRUE;
$ip = $_SERVER['REMOTE_ADDR'];
foreach ($this->subnet as $cidr) {
$ret = SimpleSAML_Utilities::ipCIDRcheck($cidr);
if ($ret) {
SimpleSAML_Logger::debug('Negotiate: Client "'.$ip.'" matched subnet.');
return TRUE;
}
}
SimpleSAML_Logger::debug('Negotiate: Client "'.$ip.'" did not match subnet.');
return FALSE;
}
/**
* Send the actual headers and body of the 401. Embedded in
* the body is a post that is triggered by JS if the client
* wants to show the 401 message.
*
* @param array $params additional parameters to the URL in
* the URL in the body
*/
protected function sendNegotiate($params) {
$url = SimpleSAML_Module::getModuleURL('negotiate/backend.php', $params);
header('HTTP/1.1 401 Unauthorized');
header('WWW-Authenticate: Negotiate',false);
echo '
<html>
<head>
<script type="text/javascript">window.location = '.json_encode(htmlspecialchars($url)).'</script>
<title>Redirect to login</title>
</head>
<body>
Your browser seems to have Javascript disabled. Please
click <a href="'.htmlspecialchars($url).'">here</a>.
</body>
</html> ';
}
/**
* Passes control of the login process to a different module.
*
* @param string $state Information about the current authentication.
*/
public static function fallBack(&$state) {
$authId = $state['LogoutState']['negotiate:backend'];
if ($authId === NULL) {
$msg = "This code should never be reached.";
throw new SimpleSAML_Error_AuthSource($msg);
}
$source = SimpleSAML_Auth_Source::getById($authId);
try {
$source->authenticate($state);
} catch (SimpleSAML_Error_Exception $e) {
SimpleSAML_Auth_State::throwException($state, $e);
} catch (Exception $e) {
$e = new SimpleSAML_Error_UnserializableException($e);
SimpleSAML_Auth_State::throwException($state, $e);
}
// fallBack never returns after loginCompleted()
SimpleSAML_Logger::debug('Negotiate: backend returned');
self::loginCompleted($state);
}
/**
* Strips away the realm of the Kerberos identifier, looks up
* what attributes to fetch from SP metadata and searches the
* directory.
*
* @param string $user The Kerberos user identifier
* @return string The DN to the user or NULL if not found
*/
protected function lookupUserData($user) {
// Kerberos usernames include realm. Strip that away.
$pos = strpos($user, '@');
if ($pos === false)
return NULL;
$uid = substr($user, 0, $pos);
$this->adminBind();
try {
$dn = $this->ldap->searchfordn($this->base, $this->attr, $uid);
return $this->ldap->getAttributes($dn);
} catch (SimpleSAML_Error_Exception $e) {
SimpleSAML_Logger::debug('Negotiate - ldap lookup failed: '. $e);
return NULL;
}
}
/**
* Elevates the LDAP connection to allow restricted lookups if
* so configured. Does nothing if not.
*/
protected function adminBind() {
if ($this->admin_user === NULL) {
// No admin user.
return;
}
SimpleSAML_Logger::debug('Negotiate - authenticate(): Binding as system user ' . var_export($this->admin_user, TRUE));
if(!$this->ldap->bind($this->admin_user, $this->admin_pw)){
$msg = 'Unable to authenticate system user (LDAP_INVALID_CREDENTIALS) ' . var_export($this->admin_user, TRUE);
SimpleSAML_Logger::error('Negotiate - authenticate(): ' . $msg);
throw new SimpleSAML_Error_AuthSource($msg);
}
}
/**
* Log out from this authentication source.
*
* This method either logs the user out from Negotiate or passes the
* logout call to the fallback module.
*
* @param array &$state Information about the current logout operation.
*/
public function logout(&$state) {
assert('is_array($state)');
/* Get the source that was used to authenticate */
$authId = $state['negotiate:backend'];
SimpleSAML_Logger::debug('Negotiate - logout has the following authId: "'.$authId.'"');
if ($authId === NULL) {
$session = SimpleSAML_Session::getInstance();
$session->setData('negotiate:disable', 'session', TRUE, 24*60*60);
parent::logout($state);
} else {
$source = SimpleSAML_Auth_Source::getById($authId);
$source->logout($state);
}
}
}
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