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<?php
/**
* This module contains code for dealing with associations between
* consumers and servers.
*
* PHP versions 4 and 5
*
* LICENSE: See the COPYING file included in this distribution.
*
* @package OpenID
* @author JanRain, Inc. <openid@janrain.com>
* @copyright 2005-2008 Janrain, Inc.
* @license http://www.apache.org/licenses/LICENSE-2.0 Apache
*/
/**
* @access private
*/
require_once 'Auth/OpenID/CryptUtil.php';
/**
* @access private
*/
require_once 'Auth/OpenID/KVForm.php';
/**
* @access private
*/
require_once 'Auth/OpenID/HMAC.php';
/**
* This class represents an association between a server and a
* consumer. In general, users of this library will never see
* instances of this object. The only exception is if you implement a
* custom {@link Auth_OpenID_OpenIDStore}.
*
* If you do implement such a store, it will need to store the values
* of the handle, secret, issued, lifetime, and assoc_type instance
* variables.
*
* @package OpenID
*/
class Auth_OpenID_Association {
/**
* This is a HMAC-SHA1 specific value.
*
* @access private
*/
var $SIG_LENGTH = 20;
/**
* The ordering and name of keys as stored by serialize.
*
* @access private
*/
var $assoc_keys = array(
'version',
'handle',
'secret',
'issued',
'lifetime',
'assoc_type'
);
var $_macs = array(
'HMAC-SHA1' => 'Auth_OpenID_HMACSHA1',
'HMAC-SHA256' => 'Auth_OpenID_HMACSHA256'
);
/**
* This is an alternate constructor (factory method) used by the
* OpenID consumer library to create associations. OpenID store
* implementations shouldn't use this constructor.
*
* @access private
*
* @param integer $expires_in This is the amount of time this
* association is good for, measured in seconds since the
* association was issued.
*
* @param string $handle This is the handle the server gave this
* association.
*
* @param string secret This is the shared secret the server
* generated for this association.
*
* @param assoc_type This is the type of association this
* instance represents. The only valid values of this field at
* this time is 'HMAC-SHA1' and 'HMAC-SHA256', but new types may
* be defined in the future.
*
* @return association An {@link Auth_OpenID_Association}
* instance.
*/
static function fromExpiresIn($expires_in, $handle, $secret, $assoc_type)
{
$issued = time();
$lifetime = $expires_in;
return new Auth_OpenID_Association($handle, $secret,
$issued, $lifetime, $assoc_type);
}
/**
* This is the standard constructor for creating an association.
* The library should create all of the necessary associations, so
* this constructor is not part of the external API.
*
* @access private
*
* @param string $handle This is the handle the server gave this
* association.
*
* @param string $secret This is the shared secret the server
* generated for this association.
*
* @param integer $issued This is the time this association was
* issued, in seconds since 00:00 GMT, January 1, 1970. (ie, a
* unix timestamp)
*
* @param integer $lifetime This is the amount of time this
* association is good for, measured in seconds since the
* association was issued.
*
* @param string $assoc_type This is the type of association this
* instance represents. The only valid values of this field at
* this time is 'HMAC-SHA1' and 'HMAC-SHA256', but new types may
* be defined in the future.
*/
function Auth_OpenID_Association(
$handle, $secret, $issued, $lifetime, $assoc_type)
{
if (!in_array($assoc_type,
Auth_OpenID_getSupportedAssociationTypes(), true)) {
$fmt = 'Unsupported association type (%s)';
trigger_error(sprintf($fmt, $assoc_type), E_USER_ERROR);
}
$this->handle = $handle;
$this->secret = $secret;
$this->issued = $issued;
$this->lifetime = $lifetime;
$this->assoc_type = $assoc_type;
}
/**
* This returns the number of seconds this association is still
* valid for, or 0 if the association is no longer valid.
*
* @return integer $seconds The number of seconds this association
* is still valid for, or 0 if the association is no longer valid.
*/
function getExpiresIn($now = null)
{
if ($now == null) {
$now = time();
}
return max(0, $this->issued + $this->lifetime - $now);
}
/**
* This checks to see if two {@link Auth_OpenID_Association}
* instances represent the same association.
*
* @return bool $result true if the two instances represent the
* same association, false otherwise.
*/
function equal($other)
{
return ((gettype($this) == gettype($other))
&& ($this->handle == $other->handle)
&& ($this->secret == $other->secret)
&& ($this->issued == $other->issued)
&& ($this->lifetime == $other->lifetime)
&& ($this->assoc_type == $other->assoc_type));
}
/**
* Convert an association to KV form.
*
* @return string $result String in KV form suitable for
* deserialization by deserialize.
*/
function serialize()
{
$data = array(
'version' => '2',
'handle' => $this->handle,
'secret' => base64_encode($this->secret),
'issued' => strval(intval($this->issued)),
'lifetime' => strval(intval($this->lifetime)),
'assoc_type' => $this->assoc_type
);
assert(array_keys($data) == $this->assoc_keys);
return Auth_OpenID_KVForm::fromArray($data, $strict = true);
}
/**
* Parse an association as stored by serialize(). This is the
* inverse of serialize.
*
* @param string $assoc_s Association as serialized by serialize()
* @return Auth_OpenID_Association $result instance of this class
*/
static function deserialize($class_name, $assoc_s)
{
$pairs = Auth_OpenID_KVForm::toArray($assoc_s, $strict = true);
$keys = array();
$values = array();
foreach ($pairs as $key => $value) {
if (is_array($value)) {
list($key, $value) = $value;
}
$keys[] = $key;
$values[] = $value;
}
$class_vars = get_class_vars($class_name);
$class_assoc_keys = $class_vars['assoc_keys'];
sort($keys);
sort($class_assoc_keys);
if ($keys != $class_assoc_keys) {
trigger_error('Unexpected key values: ' . var_export($keys, true),
E_USER_WARNING);
return null;
}
$version = $pairs['version'];
$handle = $pairs['handle'];
$secret = $pairs['secret'];
$issued = $pairs['issued'];
$lifetime = $pairs['lifetime'];
$assoc_type = $pairs['assoc_type'];
if ($version != '2') {
trigger_error('Unknown version: ' . $version, E_USER_WARNING);
return null;
}
$issued = intval($issued);
$lifetime = intval($lifetime);
$secret = base64_decode($secret);
return new $class_name(
$handle, $secret, $issued, $lifetime, $assoc_type);
}
/**
* Generate a signature for a sequence of (key, value) pairs
*
* @access private
* @param array $pairs The pairs to sign, in order. This is an
* array of two-tuples.
* @return string $signature The binary signature of this sequence
* of pairs
*/
function sign($pairs)
{
$kv = Auth_OpenID_KVForm::fromArray($pairs);
/* Invalid association types should be caught at constructor */
$callback = $this->_macs[$this->assoc_type];
return call_user_func_array($callback, array($this->secret, $kv));
}
/**
* Generate a signature for some fields in a dictionary
*
* @access private
* @param array $fields The fields to sign, in order; this is an
* array of strings.
* @param array $data Dictionary of values to sign (an array of
* string => string pairs).
* @return string $signature The signature, base64 encoded
*/
function signMessage($message)
{
if ($message->hasKey(Auth_OpenID_OPENID_NS, 'sig') ||
$message->hasKey(Auth_OpenID_OPENID_NS, 'signed')) {
// Already has a sig
return null;
}
$extant_handle = $message->getArg(Auth_OpenID_OPENID_NS,
'assoc_handle');
if ($extant_handle && ($extant_handle != $this->handle)) {
// raise ValueError("Message has a different association handle")
return null;
}
$signed_message = $message;
$signed_message->setArg(Auth_OpenID_OPENID_NS, 'assoc_handle',
$this->handle);
$message_keys = array_keys($signed_message->toPostArgs());
$signed_list = array();
$signed_prefix = 'openid.';
foreach ($message_keys as $k) {
if (strpos($k, $signed_prefix) === 0) {
$signed_list[] = substr($k, strlen($signed_prefix));
}
}
$signed_list[] = 'signed';
sort($signed_list);
$signed_message->setArg(Auth_OpenID_OPENID_NS, 'signed',
implode(',', $signed_list));
$sig = $this->getMessageSignature($signed_message);
$signed_message->setArg(Auth_OpenID_OPENID_NS, 'sig', $sig);
return $signed_message;
}
/**
* Given a {@link Auth_OpenID_Message}, return the key/value pairs
* to be signed according to the signed list in the message. If
* the message lacks a signed list, return null.
*
* @access private
*/
function _makePairs($message)
{
$signed = $message->getArg(Auth_OpenID_OPENID_NS, 'signed');
if (!$signed || Auth_OpenID::isFailure($signed)) {
// raise ValueError('Message has no signed list: %s' % (message,))
return null;
}
$signed_list = explode(',', $signed);
$pairs = array();
$data = $message->toPostArgs();
foreach ($signed_list as $field) {
$pairs[] = array($field, Auth_OpenID::arrayGet($data,
'openid.' .
$field, ''));
}
return $pairs;
}
/**
* Given an {@link Auth_OpenID_Message}, return the signature for
* the signed list in the message.
*
* @access private
*/
function getMessageSignature($message)
{
$pairs = $this->_makePairs($message);
return base64_encode($this->sign($pairs));
}
/**
* Confirm that the signature of these fields matches the
* signature contained in the data.
*
* @access private
*/
function checkMessageSignature($message)
{
$sig = $message->getArg(Auth_OpenID_OPENID_NS,
'sig');
if (!$sig || Auth_OpenID::isFailure($sig)) {
return false;
}
$calculated_sig = $this->getMessageSignature($message);
return Auth_OpenID_CryptUtil::constEq($calculated_sig, $sig);
}
}
function Auth_OpenID_getSecretSize($assoc_type)
{
if ($assoc_type == 'HMAC-SHA1') {
return 20;
} else if ($assoc_type == 'HMAC-SHA256') {
return 32;
} else {
return null;
}
}
function Auth_OpenID_getAllAssociationTypes()
{
return array('HMAC-SHA1', 'HMAC-SHA256');
}
function Auth_OpenID_getSupportedAssociationTypes()
{
$a = array('HMAC-SHA1');
if (Auth_OpenID_HMACSHA256_SUPPORTED) {
$a[] = 'HMAC-SHA256';
}
return $a;
}
function Auth_OpenID_getSessionTypes($assoc_type)
{
$assoc_to_session = array(
'HMAC-SHA1' => array('DH-SHA1', 'no-encryption'));
if (Auth_OpenID_HMACSHA256_SUPPORTED) {
$assoc_to_session['HMAC-SHA256'] =
array('DH-SHA256', 'no-encryption');
}
return Auth_OpenID::arrayGet($assoc_to_session, $assoc_type, array());
}
function Auth_OpenID_checkSessionType($assoc_type, $session_type)
{
if (!in_array($session_type,
Auth_OpenID_getSessionTypes($assoc_type))) {
return false;
}
return true;
}
function Auth_OpenID_getDefaultAssociationOrder()
{
$order = array();
if (!Auth_OpenID_noMathSupport()) {
$order[] = array('HMAC-SHA1', 'DH-SHA1');
if (Auth_OpenID_HMACSHA256_SUPPORTED) {
$order[] = array('HMAC-SHA256', 'DH-SHA256');
}
}
$order[] = array('HMAC-SHA1', 'no-encryption');
if (Auth_OpenID_HMACSHA256_SUPPORTED) {
$order[] = array('HMAC-SHA256', 'no-encryption');
}
return $order;
}
function Auth_OpenID_getOnlyEncryptedOrder()
{
$result = array();
foreach (Auth_OpenID_getDefaultAssociationOrder() as $pair) {
list($assoc, $session) = $pair;
if ($session != 'no-encryption') {
if (Auth_OpenID_HMACSHA256_SUPPORTED &&
($assoc == 'HMAC-SHA256')) {
$result[] = $pair;
} else if ($assoc != 'HMAC-SHA256') {
$result[] = $pair;
}
}
}
return $result;
}
function Auth_OpenID_getDefaultNegotiator()
{
return new Auth_OpenID_SessionNegotiator(
Auth_OpenID_getDefaultAssociationOrder());
}
function Auth_OpenID_getEncryptedNegotiator()
{
return new Auth_OpenID_SessionNegotiator(
Auth_OpenID_getOnlyEncryptedOrder());
}
/**
* A session negotiator controls the allowed and preferred association
* types and association session types. Both the {@link
* Auth_OpenID_Consumer} and {@link Auth_OpenID_Server} use
* negotiators when creating associations.
*
* You can create and use negotiators if you:
* - Do not want to do Diffie-Hellman key exchange because you use
* transport-layer encryption (e.g. SSL)
*
* - Want to use only SHA-256 associations
*
* - Do not want to support plain-text associations over a non-secure
* channel
*
* It is up to you to set a policy for what kinds of associations to
* accept. By default, the library will make any kind of association
* that is allowed in the OpenID 2.0 specification.
*
* Use of negotiators in the library
* =================================
*
* When a consumer makes an association request, it calls {@link
* getAllowedType} to get the preferred association type and
* association session type.
*
* The server gets a request for a particular association/session type
* and calls {@link isAllowed} to determine if it should create an
* association. If it is supported, negotiation is complete. If it is
* not, the server calls {@link getAllowedType} to get an allowed
* association type to return to the consumer.
*
* If the consumer gets an error response indicating that the
* requested association/session type is not supported by the server
* that contains an assocation/session type to try, it calls {@link
* isAllowed} to determine if it should try again with the given
* combination of association/session type.
*
* @package OpenID
*/
class Auth_OpenID_SessionNegotiator {
function Auth_OpenID_SessionNegotiator($allowed_types)
{
$this->allowed_types = array();
$this->setAllowedTypes($allowed_types);
}
/**
* Set the allowed association types, checking to make sure each
* combination is valid.
*
* @access private
*/
function setAllowedTypes($allowed_types)
{
foreach ($allowed_types as $pair) {
list($assoc_type, $session_type) = $pair;
if (!Auth_OpenID_checkSessionType($assoc_type, $session_type)) {
return false;
}
}
$this->allowed_types = $allowed_types;
return true;
}
/**
* Add an association type and session type to the allowed types
* list. The assocation/session pairs are tried in the order that
* they are added.
*
* @access private
*/
function addAllowedType($assoc_type, $session_type = null)
{
if ($this->allowed_types === null) {
$this->allowed_types = array();
}
if ($session_type === null) {
$available = Auth_OpenID_getSessionTypes($assoc_type);
if (!$available) {
return false;
}
foreach ($available as $session_type) {
$this->addAllowedType($assoc_type, $session_type);
}
} else {
if (Auth_OpenID_checkSessionType($assoc_type, $session_type)) {
$this->allowed_types[] = array($assoc_type, $session_type);
} else {
return false;
}
}
return true;
}
// Is this combination of association type and session type allowed?
function isAllowed($assoc_type, $session_type)
{
$assoc_good = in_array(array($assoc_type, $session_type),
$this->allowed_types);
$matches = in_array($session_type,
Auth_OpenID_getSessionTypes($assoc_type));
return ($assoc_good && $matches);
}
/**
* Get a pair of assocation type and session type that are
* supported.
*/
function getAllowedType()
{
if (!$this->allowed_types) {
return array(null, null);
}
return $this->allowed_types[0];
}
}
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