Performs the first step of a Diffie-Hellman key exchange by generating
private and public DH values based on given prime number $p and
generator $g. Both sides of key exchange MUST have the same prime number
and generator. In this case they will able to create a random shared
secret that is never send from one to the other.
/**
* Create (or reuse existing) association between OpenID consumer and
* OpenID server based on Diffie-Hellman key agreement. Returns true
* on success and false on failure.
*
* @param string $url OpenID server url
* @param float $version OpenID protocol version
* @param string $priv_key for testing only
* @return bool
*/
protected function _associate($url, $version, $priv_key = null)
{
/* Check if we already have association in chace or storage */
if ($this->_getAssociation($url, $handle, $macFunc, $secret, $expires)) {
return true;
}
if ($this->_dumbMode) {
/* Use dumb mode */
return true;
}
$params = array();
if ($version >= 2.0) {
$params = array('openid.ns' => Zend_OpenId::NS_2_0, 'openid.mode' => 'associate', 'openid.assoc_type' => 'HMAC-SHA256', 'openid.session_type' => 'DH-SHA256');
} else {
$params = array('openid.mode' => 'associate', 'openid.assoc_type' => 'HMAC-SHA1', 'openid.session_type' => 'DH-SHA1');
}
$dh = Zend_OpenId::createDhKey(pack('H*', Zend_OpenId::DH_P), pack('H*', Zend_OpenId::DH_G), $priv_key);
$dh_details = Zend_OpenId::getDhKeyDetails($dh);
$params['openid.dh_modulus'] = base64_encode(Zend_OpenId::btwoc($dh_details['p']));
$params['openid.dh_gen'] = base64_encode(Zend_OpenId::btwoc($dh_details['g']));
$params['openid.dh_consumer_public'] = base64_encode(Zend_OpenId::btwoc($dh_details['pub_key']));
while (1) {
$ret = $this->_httpRequest($url, 'POST', $params, $status);
if ($ret === false) {
$this->_setError("HTTP request failed");
return false;
}
$r = array();
$bad_response = false;
foreach (explode("\n", $ret) as $line) {
$line = trim($line);
if (!empty($line)) {
$x = explode(':', $line, 2);
if (is_array($x) && count($x) == 2) {
list($key, $value) = $x;
$r[trim($key)] = trim($value);
} else {
$bad_response = true;
}
}
}
if ($bad_response && strpos($ret, 'Unknown session type') !== false) {
$r['error_code'] = 'unsupported-type';
}
$ret = $r;
if (isset($ret['error_code']) && $ret['error_code'] == 'unsupported-type') {
if ($params['openid.session_type'] == 'DH-SHA256') {
$params['openid.session_type'] = 'DH-SHA1';
$params['openid.assoc_type'] = 'HMAC-SHA1';
} else {
if ($params['openid.session_type'] == 'DH-SHA1') {
$params['openid.session_type'] = 'no-encryption';
} else {
$this->_setError("The OpenID service responded with: " . $ret['error_code']);
return false;
}
}
} else {
break;
}
}
if ($status != 200) {
$this->_setError("The server responded with status code: " . $status);
return false;
}
if ($version >= 2.0 && isset($ret['ns']) && $ret['ns'] != Zend_OpenId::NS_2_0) {
$this->_setError("Wrong namespace definition in the server response");
return false;
}
if (!isset($ret['assoc_handle']) || !isset($ret['expires_in']) || !isset($ret['assoc_type']) || $params['openid.assoc_type'] != $ret['assoc_type']) {
if ($params['openid.assoc_type'] != $ret['assoc_type']) {
$this->_setError("The returned assoc_type differed from the supplied openid.assoc_type");
} else {
$this->_setError("Missing required data from provider (assoc_handle, expires_in, assoc_type are required)");
}
return false;
}
$handle = $ret['assoc_handle'];
$expiresIn = $ret['expires_in'];
if ($ret['assoc_type'] == 'HMAC-SHA1') {
$macFunc = 'sha1';
} else {
if ($ret['assoc_type'] == 'HMAC-SHA256' && $version >= 2.0) {
$macFunc = 'sha256';
} else {
$this->_setError("Unsupported assoc_type");
return false;
}
}
if ((empty($ret['session_type']) || $version >= 2.0 && $ret['session_type'] == 'no-encryption') && isset($ret['mac_key'])) {
$secret = base64_decode($ret['mac_key']);
} else {
if (isset($ret['session_type']) && $ret['session_type'] == 'DH-SHA1' && !empty($ret['dh_server_public']) && !empty($ret['enc_mac_key'])) {
$dhFunc = 'sha1';
} else {
if (isset($ret['session_type']) && $ret['session_type'] == 'DH-SHA256' && $version >= 2.0 && !empty($ret['dh_server_public']) && !empty($ret['enc_mac_key'])) {
$dhFunc = 'sha256';
} else {
$this->_setError("Unsupported session_type");
return false;
}
}
}
if (isset($dhFunc)) {
$serverPub = base64_decode($ret['dh_server_public']);
$dhSec = Zend_OpenId::computeDhSecret($serverPub, $dh);
if ($dhSec === false) {
$this->_setError("DH secret comutation failed");
return false;
}
$sec = Zend_OpenId::digest($dhFunc, $dhSec);
if ($sec === false) {
$this->_setError("Could not create digest");
return false;
}
$secret = $sec ^ base64_decode($ret['enc_mac_key']);
}
if ($macFunc == 'sha1') {
if (Zend_OpenId::strlen($secret) != 20) {
$this->_setError("The length of the sha1 secret must be 20");
return false;
}
} else {
if ($macFunc == 'sha256') {
if (Zend_OpenId::strlen($secret) != 32) {
$this->_setError("The length of the sha256 secret must be 32");
return false;
}
}
}
$this->_addAssociation($url, $handle, $macFunc, $secret, time() + $expiresIn);
return true;
}
/**
* Processes association request from OpenID consumerm generates secret
* shared key and send it back using Diffie-Hellman encruption.
* Returns array of variables to push back to consumer.
*
* @param float $version OpenID version
* @param array $params GET or POST request variables
* @return array
*/
protected function _associate($version, $params)
{
$ret = array();
if ($version >= 2.0) {
$ret['ns'] = Zend_OpenId::NS_2_0;
}
if (isset($params['openid_assoc_type']) && $params['openid_assoc_type'] == 'HMAC-SHA1') {
$macFunc = 'sha1';
} else {
if (isset($params['openid_assoc_type']) && $params['openid_assoc_type'] == 'HMAC-SHA256' && $version >= 2.0) {
$macFunc = 'sha256';
} else {
$ret['error'] = 'Wrong "openid.assoc_type"';
$ret['error-code'] = 'unsupported-type';
return $ret;
}
}
$ret['assoc_type'] = $params['openid_assoc_type'];
$secret = $this->_genSecret($macFunc);
if (empty($params['openid_session_type']) || $params['openid_session_type'] == 'no-encryption') {
$ret['mac_key'] = base64_encode($secret);
} else {
if (isset($params['openid_session_type']) && $params['openid_session_type'] == 'DH-SHA1') {
$dhFunc = 'sha1';
} else {
if (isset($params['openid_session_type']) && $params['openid_session_type'] == 'DH-SHA256' && $version >= 2.0) {
$dhFunc = 'sha256';
} else {
$ret['error'] = 'Wrong "openid.session_type"';
$ret['error-code'] = 'unsupported-type';
return $ret;
}
}
}
if (isset($params['openid_session_type'])) {
$ret['session_type'] = $params['openid_session_type'];
}
if (isset($dhFunc)) {
if (empty($params['openid_dh_consumer_public'])) {
$ret['error'] = 'Wrong "openid.dh_consumer_public"';
return $ret;
}
if (empty($params['openid_dh_gen'])) {
$g = pack('H*', Zend_OpenId::DH_G);
} else {
$g = base64_decode($params['openid_dh_gen']);
}
if (empty($params['openid_dh_modulus'])) {
$p = pack('H*', Zend_OpenId::DH_P);
} else {
$p = base64_decode($params['openid_dh_modulus']);
}
$dh = Zend_OpenId::createDhKey($p, $g);
$dh_details = Zend_OpenId::getDhKeyDetails($dh);
$sec = Zend_OpenId::computeDhSecret(base64_decode($params['openid_dh_consumer_public']), $dh);
if ($sec === false) {
$ret['error'] = 'Wrong "openid.session_type"';
$ret['error-code'] = 'unsupported-type';
return $ret;
}
$sec = Zend_OpenId::digest($dhFunc, $sec);
$ret['dh_server_public'] = base64_encode(Zend_OpenId::btwoc($dh_details['pub_key']));
$ret['enc_mac_key'] = base64_encode($secret ^ $sec);
}
$handle = uniqid();
$expiresIn = $this->_sessionTtl;
$ret['assoc_handle'] = $handle;
$ret['expires_in'] = $expiresIn;
$this->_storage->addAssociation($handle, $macFunc, $secret, time() + $expiresIn);
return $ret;
}
/**
* Create (or reuse existing) association between OpenID consumer and
* OpenID server based on Diffie-Hellman key agreement. Returns true
* on success and false on failure.
*
* @param string $url OpenID server url
* @param float $version OpenID protocol version
* @param string $priv_key for testing only
* @return bool
*/
protected function _associate($url, $version, $priv_key = null)
{
/* Check if we already have association in chace or storage */
if ($this->_getAssociation($url, $handle, $macFunc, $secret, $expires)) {
return true;
}
if ($this->_dumbMode) {
/* Use dumb mode */
return true;
}
$params = array();
if ($version >= 2.0) {
$params = array('openid.ns' => Zend_OpenId::NS_2_0, 'openid.mode' => 'associate', 'openid.assoc_type' => 'HMAC-SHA256', 'openid.session_type' => 'DH-SHA256');
} else {
$params = array('openid.mode' => 'associate', 'openid.assoc_type' => 'HMAC-SHA1', 'openid.session_type' => 'DH-SHA1');
}
$dh = Zend_OpenId::createDhKey(pack('H*', Zend_OpenId::DH_P), pack('H*', Zend_OpenId::DH_G), $priv_key);
$dh_details = Zend_OpenId::getDhKeyDetails($dh);
$params['openid.dh_modulus'] = base64_encode(Zend_OpenId::btwoc($dh_details['p']));
$params['openid.dh_gen'] = base64_encode(Zend_OpenId::btwoc($dh_details['g']));
$params['openid.dh_consumer_public'] = base64_encode(Zend_OpenId::btwoc($dh_details['pub_key']));
while (1) {
$ret = $this->_httpRequest($url, 'POST', $params, $status);
if ($ret === false) {
return false;
}
$r = array();
foreach (explode("\n", $ret) as $line) {
$line = trim($line);
if (!empty($line)) {
$x = explode(':', $line, 2);
if (is_array($x) && count($x) == 2) {
list($key, $value) = $x;
$r[trim($key)] = trim($value);
}
}
}
$ret = $r;
if (isset($ret['error_code']) && $ret['error_code'] == 'unsupported-type') {
if ($params['openid.session_type'] == 'DH-SHA256') {
$params['openid.session_type'] = 'DH-SHA1';
$params['openid.assoc_type'] = 'HMAC-SHA1';
} else {
if ($params['openid.session_type'] == 'DH-SHA1') {
$params['openid.session_type'] = 'no-encryption';
} else {
return false;
}
}
} else {
break;
}
}
if ($status != 200) {
return false;
}
if ($version >= 2.0 && isset($ret['ns']) && $ret['ns'] != Zend_OpenId::NS_2_0) {
return false;
}
if (!isset($ret['assoc_handle']) || !isset($ret['expires_in']) || !isset($ret['assoc_type']) || $params['openid.assoc_type'] != $ret['assoc_type']) {
return false;
}
$handle = $ret['assoc_handle'];
$expiresIn = $ret['expires_in'];
if ($ret['assoc_type'] == 'HMAC-SHA1') {
$macFunc = 'sha1';
} else {
if ($ret['assoc_type'] == 'HMAC-SHA256' && $version >= 2.0) {
$macFunc = 'sha256';
} else {
return false;
}
}
if ((empty($ret['session_type']) || $version >= 2.0 && $ret['session_type'] == 'no-encryption') && isset($ret['mac_key'])) {
$secret = base64_decode($ret['mac_key']);
} else {
if (isset($ret['session_type']) && $ret['session_type'] == 'DH-SHA1' && !empty($ret['dh_server_public']) && !empty($ret['enc_mac_key'])) {
$dhFunc = 'sha1';
} else {
if (isset($ret['session_type']) && $ret['session_type'] == 'DH-SHA256' && $version >= 2.0 && !empty($ret['dh_server_public']) && !empty($ret['enc_mac_key'])) {
$dhFunc = 'sha256';
} else {
return false;
}
}
}
if (isset($dhFunc)) {
$serverPub = base64_decode($ret['dh_server_public']);
$dhSec = Zend_OpenId::computeDhSecret($serverPub, $dh);
if ($dhSec === false) {
return false;
}
$sec = Zend_OpenId::digest($dhFunc, $dhSec);
if ($sec === false) {
return false;
}
$secret = $sec ^ base64_decode($ret['enc_mac_key']);
}
if ($macFunc == 'sha1') {
if (strlen($secret) != 20) {
return false;
}
} else {
if ($macFunc == 'sha256') {
if (strlen($secret) != 32) {
return false;
}
}
}
$this->_addAssociation($url, $handle, $macFunc, $secret, time() + $expiresIn);
return true;
}
/**
* testing testComputeDhSecret
*
*/
public function testComputeDhSecret()
{
try {
$alice = Zend_OpenId::createDhKey(
pack('H*', '0233'),
pack('H*', '05'),
pack('H*', '09'));
$alice_details = Zend_OpenId::getDhKeyDetails($alice);
$this->assertSame( '4e', bin2hex($alice_details['pub_key']) );
$bob = Zend_OpenId::createDhKey(
pack('H*', '0233'),
pack('H*', '05'),
pack('H*', '0e'));
$bob_details = Zend_OpenId::getDhKeyDetails($bob);
$this->assertSame( '0216', bin2hex($bob_details['pub_key']) );
$this->assertSame( '75',
bin2hex(Zend_OpenId::computeDhSecret($alice_details['pub_key'], $bob)) );
$this->assertSame( '75',
bin2hex(Zend_OpenId::computeDhSecret($bob_details['pub_key'], $alice)) );
} catch (Zend_OpenId_Exception $e) {
$this->markTestSkipped($e->getMessage());
}
}
/**
* testing testComputeDhSecret
*
*/
public function testComputeDhSecret()
{
$alice = Zend_OpenId::createDhKey(
pack('H*', '0233'),
pack('H*', '05'),
pack('H*', '09'));
$alice_details = Zend_OpenId::getDhKeyDetails($alice);
$this->assertSame( '4e', bin2hex($alice_details['pub_key']) );
$bob = Zend_OpenId::createDhKey(
pack('H*', '0233'),
pack('H*', '05'),
pack('H*', '0e'));
$bob_details = Zend_OpenId::getDhKeyDetails($bob);
$this->assertSame( '0216', bin2hex($bob_details['pub_key']) );
$this->assertSame( '75',
bin2hex(Zend_OpenId::computeDhSecret($alice_details['pub_key'], $bob)) );
$this->assertSame( '75',
bin2hex(Zend_OpenId::computeDhSecret($bob_details['pub_key'], $alice)) );
}