/**
* Decrypts an encrypted element.
*
* @param DOMElement $encryptedData The encrypted data.
* @param XMLSecurityKey $inputKey The decryption key.
*
* @return DOMElement The decrypted element.
*/
public static function decryptElement(DOMElement $encryptedData, XMLSecurityKey $inputKey)
{
$enc = new XMLSecEnc();
$enc->setNode($encryptedData);
$enc->type = $encryptedData->getAttribute("Type");
$symmetricKey = $enc->locateKey($encryptedData);
if (!$symmetricKey) {
throw new Exception('Could not locate key algorithm in encrypted data.');
}
$symmetricKeyInfo = $enc->locateKeyInfo($symmetricKey);
if (!$symmetricKeyInfo) {
throw new Exception('Could not locate <dsig:KeyInfo> for the encrypted key.');
}
$inputKeyAlgo = $inputKey->getAlgorith();
if ($symmetricKeyInfo->isEncrypted) {
$symKeyInfoAlgo = $symmetricKeyInfo->getAlgorith();
if ($symKeyInfoAlgo === XMLSecurityKey::RSA_OAEP_MGF1P && $inputKeyAlgo === XMLSecurityKey::RSA_1_5) {
$inputKeyAlgo = XMLSecurityKey::RSA_OAEP_MGF1P;
}
if ($inputKeyAlgo !== $symKeyInfoAlgo) {
throw new Exception('Algorithm mismatch between input key and key used to encrypt ' . ' the symmetric key for the message. Key was: ' . var_export($inputKeyAlgo, true) . '; message was: ' . var_export($symKeyInfoAlgo, true));
}
$encKey = $symmetricKeyInfo->encryptedCtx;
$symmetricKeyInfo->key = $inputKey->key;
$keySize = $symmetricKey->getSymmetricKeySize();
if ($keySize === null) {
// To protect against "key oracle" attacks
throw new Exception('Unknown key size for encryption algorithm: ' . var_export($symmetricKey->type, true));
}
$key = $encKey->decryptKey($symmetricKeyInfo);
if (strlen($key) != $keySize) {
$encryptedKey = $encKey->getCipherValue();
$pkey = openssl_pkey_get_details($symmetricKeyInfo->key);
$pkey = sha1(serialize($pkey), true);
$key = sha1($encryptedKey . $pkey, true);
/* Make sure that the key has the correct length. */
if (strlen($key) > $keySize) {
$key = substr($key, 0, $keySize);
} elseif (strlen($key) < $keySize) {
$key = str_pad($key, $keySize);
}
}
$symmetricKey->loadkey($key);
} else {
$symKeyAlgo = $symmetricKey->getAlgorith();
if ($inputKeyAlgo !== $symKeyAlgo) {
throw new Exception('Algorithm mismatch between input key and key in message. ' . 'Key was: ' . var_export($inputKeyAlgo, true) . '; message was: ' . var_export($symKeyAlgo, true));
}
$symmetricKey = $inputKey;
}
$decrypted = $enc->decryptNode($symmetricKey, false);
$xml = '<root xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">' . $decrypted . '</root>';
$newDoc = new DOMDocument();
$newDoc->preserveWhiteSpace = false;
$newDoc->formatOutput = true;
$newDoc = self::loadXML($newDoc, $xml);
if (!$newDoc) {
throw new Exception('Failed to parse decrypted XML.');
}
$decryptedElement = $newDoc->firstChild->firstChild;
if ($decryptedElement === null) {
throw new Exception('Missing encrypted element.');
}
return $decryptedElement;
}
/**
* Decrypts an encrypted element.
*
* @param DOMElement $encryptedData The encrypted data.
* @param XMLSecurityKey $inputKey The decryption key.
*
* @return DOMElement The decrypted element.
*/
public static function decryptElement(DOMElement $encryptedData, XMLSecurityKey $inputKey)
{
$enc = new XMLSecEnc();
$enc->setNode($encryptedData);
$enc->type = $encryptedData->getAttribute("Type");
$symmetricKey = $enc->locateKey($encryptedData);
if (!$symmetricKey) {
throw new Exception('Could not locate key algorithm in encrypted data.');
}
$symmetricKeyInfo = $enc->locateKeyInfo($symmetricKey);
if (!$symmetricKeyInfo) {
throw new Exception('Could not locate <dsig:KeyInfo> for the encrypted key.');
}
$inputKeyAlgo = $inputKey->getAlgorith();
if ($symmetricKeyInfo->isEncrypted) {
$symKeyInfoAlgo = $symmetricKeyInfo->getAlgorith();
if ($symKeyInfoAlgo === XMLSecurityKey::RSA_OAEP_MGF1P && $inputKeyAlgo === XMLSecurityKey::RSA_1_5) {
$inputKeyAlgo = XMLSecurityKey::RSA_OAEP_MGF1P;
}
if ($inputKeyAlgo !== $symKeyInfoAlgo) {
throw new Exception('Algorithm mismatch between input key and key used to encrypt ' . ' the symmetric key for the message. Key was: ' . var_export($inputKeyAlgo, true) . '; message was: ' . var_export($symKeyInfoAlgo, true));
}
$encKey = $symmetricKeyInfo->encryptedCtx;
$symmetricKeyInfo->key = $inputKey->key;
$key = $encKey->decryptKey($symmetricKeyInfo);
$symmetricKey->loadkey($key);
} else {
$symKeyAlgo = $symmetricKey->getAlgorith();
if ($inputKeyAlgo !== $symKeyAlgo) {
throw new Exception('Algorithm mismatch between input key and key in message. ' . 'Key was: ' . var_export($inputKeyAlgo, true) . '; message was: ' . var_export($symKeyAlgo, true));
}
$symmetricKey = $inputKey;
}
$decrypted = $enc->decryptNode($symmetricKey, false);
$xml = '<root xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">' . $decrypted . '</root>';
$newDoc = new DOMDocument();
$newDoc = self::loadXML($newDoc, $xml);
if (!$newDoc) {
throw new Exception('Failed to parse decrypted XML. Maybe the wrong sharedkey was used?');
}
$decryptedElement = $newDoc->firstChild->firstChild;
if ($decryptedElement === null) {
throw new Exception('Missing encrypted element.');
}
return $decryptedElement;
}
/**
* Decrypt an encrypted element.
*
* This is an internal helper function.
*
* @param DOMElement $encryptedData The encrypted data.
* @param XMLSecurityKey $inputKey The decryption key.
* @param array &$blacklist Blacklisted decryption algorithms.
* @return DOMElement The decrypted element.
* @throws Exception
*/
private static function doDecryptElement(DOMElement $encryptedData, XMLSecurityKey $inputKey, array &$blacklist)
{
$enc = new XMLSecEnc();
$enc->setNode($encryptedData);
$enc->type = $encryptedData->getAttribute("Type");
$symmetricKey = $enc->locateKey($encryptedData);
if (!$symmetricKey) {
throw new Exception('Could not locate key algorithm in encrypted data.');
}
$symmetricKeyInfo = $enc->locateKeyInfo($symmetricKey);
if (!$symmetricKeyInfo) {
throw new Exception('Could not locate <dsig:KeyInfo> for the encrypted key.');
}
$inputKeyAlgo = $inputKey->getAlgorith();
if ($symmetricKeyInfo->isEncrypted) {
$symKeyInfoAlgo = $symmetricKeyInfo->getAlgorith();
if (in_array($symKeyInfoAlgo, $blacklist, TRUE)) {
throw new Exception('Algorithm disabled: ' . var_export($symKeyInfoAlgo, TRUE));
}
if ($symKeyInfoAlgo === XMLSecurityKey::RSA_OAEP_MGF1P && $inputKeyAlgo === XMLSecurityKey::RSA_1_5) {
/*
* The RSA key formats are equal, so loading an RSA_1_5 key
* into an RSA_OAEP_MGF1P key can be done without problems.
* We therefore pretend that the input key is an
* RSA_OAEP_MGF1P key.
*/
$inputKeyAlgo = XMLSecurityKey::RSA_OAEP_MGF1P;
}
/* Make sure that the input key format is the same as the one used to encrypt the key. */
if ($inputKeyAlgo !== $symKeyInfoAlgo) {
throw new Exception('Algorithm mismatch between input key and key used to encrypt ' . ' the symmetric key for the message. Key was: ' . var_export($inputKeyAlgo, TRUE) . '; message was: ' . var_export($symKeyInfoAlgo, TRUE));
}
/** @var XMLSecEnc $encKey */
$encKey = $symmetricKeyInfo->encryptedCtx;
$symmetricKeyInfo->key = $inputKey->key;
$keySize = $symmetricKey->getSymmetricKeySize();
if ($keySize === NULL) {
/* To protect against "key oracle" attacks, we need to be able to create a
* symmetric key, and for that we need to know the key size.
*/
throw new Exception('Unknown key size for encryption algorithm: ' . var_export($symmetricKey->type, TRUE));
}
try {
$key = $encKey->decryptKey($symmetricKeyInfo);
if (strlen($key) != $keySize) {
throw new Exception('Unexpected key size (' . strlen($key) * 8 . 'bits) for encryption algorithm: ' . var_export($symmetricKey->type, TRUE));
}
} catch (Exception $e) {
/* We failed to decrypt this key. Log it, and substitute a "random" key. */
SAML2_Utils::getContainer()->getLogger()->error('Failed to decrypt symmetric key: ' . $e->getMessage());
/* Create a replacement key, so that it looks like we fail in the same way as if the key was correctly padded. */
/* We base the symmetric key on the encrypted key and private key, so that we always behave the
* same way for a given input key.
*/
$encryptedKey = $encKey->getCipherValue();
$pkey = openssl_pkey_get_details($symmetricKeyInfo->key);
$pkey = sha1(serialize($pkey), TRUE);
$key = sha1($encryptedKey . $pkey, TRUE);
/* Make sure that the key has the correct length. */
if (strlen($key) > $keySize) {
$key = substr($key, 0, $keySize);
} elseif (strlen($key) < $keySize) {
$key = str_pad($key, $keySize);
}
}
$symmetricKey->loadkey($key);
} else {
$symKeyAlgo = $symmetricKey->getAlgorith();
/* Make sure that the input key has the correct format. */
if ($inputKeyAlgo !== $symKeyAlgo) {
throw new Exception('Algorithm mismatch between input key and key in message. ' . 'Key was: ' . var_export($inputKeyAlgo, TRUE) . '; message was: ' . var_export($symKeyAlgo, TRUE));
}
$symmetricKey = $inputKey;
}
$algorithm = $symmetricKey->getAlgorith();
if (in_array($algorithm, $blacklist, TRUE)) {
throw new Exception('Algorithm disabled: ' . var_export($algorithm, TRUE));
}
/** @var string $decrypted */
$decrypted = $enc->decryptNode($symmetricKey, FALSE);
/*
* This is a workaround for the case where only a subset of the XML
* tree was serialized for encryption. In that case, we may miss the
* namespaces needed to parse the XML.
*/
$xml = '<root xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion" ' . 'xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">' . $decrypted . '</root>';
$newDoc = new DOMDocument();
if (!@$newDoc->loadXML($xml)) {
throw new Exception('Failed to parse decrypted XML. Maybe the wrong sharedkey was used?');
}
$decryptedElement = $newDoc->firstChild->firstChild;
if ($decryptedElement === NULL) {
throw new Exception('Missing encrypted element.');
}
if (!$decryptedElement instanceof DOMElement) {
throw new Exception('Decrypted element was not actually a DOMElement.');
}
return $decryptedElement;
}
/**
* Decrypts the Assertion (DOMDocument)
*
* @param string $dom DomDocument
*
* @throws Exception
* @return DOMDocument Decrypted Assertion
*/
private function _decryptAssertion($dom)
{
$pem = $this->_settings->getSPkey();
if (empty($pem)) {
throw new Exception("No private key available, check settings");
}
$objenc = new XMLSecEnc();
$encData = $objenc->locateEncryptedData($dom);
if (!$encData) {
throw new Exception("Cannot locate encrypted assertion");
}
$objenc->setNode($encData);
$objenc->type = $encData->getAttribute("Type");
if (!($objKey = $objenc->locateKey())) {
throw new Exception("Unknown algorithm");
}
$key = null;
if ($objKeyInfo = $objenc->locateKeyInfo($objKey)) {
if ($objKeyInfo->isEncrypted) {
$objencKey = $objKeyInfo->encryptedCtx;
$objKeyInfo->loadKey($pem, false, false);
$key = $objencKey->decryptKey($objKeyInfo);
}
}
if (empty($objKey->key)) {
$objKey->loadKey($key);
}
$decrypt = $objenc->decryptNode($objKey, true);
if ($decrypt instanceof DOMDocument) {
return $decrypt;
} else {
return $decrypt->ownerDocument;
}
}
/**
* Decrypt an encrypted element.
*
* @param DOMElement $encryptedData The encrypted data.
* @param XMLSecurityKey $inputKey The decryption key.
* @return DOMElement The decrypted element.
*/
public static function decryptElement(DOMElement $encryptedData, XMLSecurityKey $inputKey)
{
$enc = new XMLSecEnc();
$enc->setNode($encryptedData);
$enc->type = $encryptedData->getAttribute("Type");
$symmetricKey = $enc->locateKey($encryptedData);
if (!$symmetricKey) {
throw new Exception('Could not locate key algorithm in encrypted data.');
}
$symmetricKeyInfo = $enc->locateKeyInfo($symmetricKey);
if (!$symmetricKeyInfo) {
throw new Exception('Could not locate <dsig:KeyInfo> for the encrypted key.');
}
$inputKeyAlgo = $inputKey->getAlgorith();
if ($symmetricKeyInfo->isEncrypted) {
$symKeyInfoAlgo = $symmetricKeyInfo->getAlgorith();
if ($symKeyInfoAlgo === XMLSecurityKey::RSA_OAEP_MGF1P && $inputKeyAlgo === XMLSecurityKey::RSA_1_5) {
/*
* The RSA key formats are equal, so loading an RSA_1_5 key
* into an RSA_OAEP_MGF1P key can be done without problems.
* We therefore pretend that the input key is an
* RSA_OAEP_MGF1P key.
*/
$inputKeyAlgo = XMLSecurityKey::RSA_OAEP_MGF1P;
}
/* Make sure that the input key format is the same as the one used to encrypt the key. */
if ($inputKeyAlgo !== $symKeyInfoAlgo) {
throw new Exception('Algorithm mismatch between input key and key used to encrypt ' . ' the symmetric key for the message. Key was: ' . var_export($inputKeyAlgo, TRUE) . '; message was: ' . var_export($symKeyInfoAlgo, TRUE));
}
$encKey = $symmetricKeyInfo->encryptedCtx;
$symmetricKeyInfo->key = $inputKey->key;
$key = $encKey->decryptKey($symmetricKeyInfo);
$symmetricKey->loadkey($key);
} else {
$symKeyAlgo = $symmetricKey->getAlgorith();
/* Make sure that the input key has the correct format. */
if ($inputKeyAlgo !== $symKeyAlgo) {
throw new Exception('Algorithm mismatch between input key and key in message. ' . 'Key was: ' . var_export($inputKeyAlgo, TRUE) . '; message was: ' . var_export($symKeyAlgo, TRUE));
}
$symmetricKey = $inputKey;
}
$decrypted = $enc->decryptNode($symmetricKey, FALSE);
/*
* This is a workaround for the case where only a subset of the XML
* tree was serialized for encryption. In that case, we may miss the
* namespaces needed to parse the XML.
*/
$xml = '<root xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">' . $decrypted . '</root>';
$newDoc = new DOMDocument();
if (!$newDoc->loadXML($xml)) {
throw new Exception('Failed to parse decrypted XML. Maybe the wrong sharedkey was used?');
}
$decryptedElement = $newDoc->firstChild->firstChild;
if ($decryptedElement === NULL) {
throw new Exception('Missing encrypted element.');
}
return $decryptedElement;
}
/**
* This function decrypts the Assertion in the AuthnResponse
* It throws an exception if the encryptAssertion for the remote idp is true and
* the assertion is not encrypted
* To Do: handle multible assertions
*/
private function decryptAssertion()
{
$dom = $this->getDOM();
$encryptedassertion = $this->doXPathQuery('/samlp:Response/saml:EncryptedAssertion')->item(0);
$objenc = new XMLSecEnc();
$encData = $objenc->locateEncryptedData($dom);
if ($encData) {
$spmd = $this->metadata->getMetaDataCurrent('saml20-sp-hosted');
$spid = $this->metadata->getMetaDataCurrentEntityID('saml20-sp-hosted');
$objenc->setNode($encData);
$objenc->type = $encData->getAttribute("Type");
$key = NULL;
$objKey = $objenc->locateKey($encData);
if ($objKey) {
if ($objKeyInfo = $objenc->locateKeyInfo($objKey)) {
if ($objKeyInfo->isEncrypted) {
$objencKey = $objKeyInfo->encryptedCtx;
if (empty($spmd['privatekey'])) {
throw new Exception("SAML: RSA private key not configured. This is required to decrypt the response. saml20-sp-hosted: {$spid}");
}
$objKeyInfo->loadKey($spmd['privatekey']);
$key = $objencKey->decryptKey($objKeyInfo);
} else {
$idpmd = $this->metadata->getMetaData($this->issuer, 'saml20-idp-remote');
if (!isset($idpmd['sharedkey'])) {
throw new Exception("Shared key for decrypting assertion needed, but not specified for saml20-idp-remote id: " . $this->issuer);
}
$key = $idpmd['sharedkey'];
}
}
}
if (empty($objKey) || empty($key)) {
throw new Exception("Error loading key to handle Decryption: >" . var_export($objKey, true));
}
$objKey->loadkey($key);
$decrypted = $objenc->decryptNode($objKey, false);
$newdoc = new DOMDocument();
$newdoc->loadXML('<root xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">' . $decrypted . '</root>');
$importEnc = $encData->ownerDocument->importNode($newdoc->documentElement->firstChild, TRUE);
$encryptedassertion->parentNode->replaceChild($importEnc, $encryptedassertion);
} else {
$md = $this->metadata->getMetaData($this->issuer, 'saml20-idp-remote');
if (isset($md['assertion.encryption']) && $md['assertion.encryption']) {
throw new Exception('Received unencrypted assertion from [' . $this->issuer . '] contrary to its metadata attribute [assertion.encryption]: ' . $md['assertion.encryption']);
}
}
}
/**
* Decrypts the Assertion (DOMDocument)
*
* @param DomNode $dom DomDocument
*
* @return DOMDocument Decrypted Assertion
*
* @throws Exception
*/
protected function _decryptAssertion($dom)
{
$pem = $this->_settings->getSPkey();
if (empty($pem)) {
throw new Exception("No private key available, check settings");
}
$objenc = new XMLSecEnc();
$encData = $objenc->locateEncryptedData($dom);
if (!$encData) {
throw new Exception("Cannot locate encrypted assertion");
}
$objenc->setNode($encData);
$objenc->type = $encData->getAttribute("Type");
if (!($objKey = $objenc->locateKey())) {
throw new Exception("Unknown algorithm");
}
$key = null;
if ($objKeyInfo = $objenc->locateKeyInfo($objKey)) {
if ($objKeyInfo->isEncrypted) {
$objencKey = $objKeyInfo->encryptedCtx;
$objKeyInfo->loadKey($pem, false, false);
$key = $objencKey->decryptKey($objKeyInfo);
} else {
// symmetric encryption key support
$objKeyInfo->loadKey($pem, false, false);
}
}
if (empty($objKey->key)) {
$objKey->loadKey($key);
}
$decrypted = $objenc->decryptNode($objKey, true);
if ($decrypted instanceof DOMDocument) {
return $decrypted;
} else {
$encryptedAssertion = $decrypted->parentNode;
$container = $encryptedAssertion->parentNode;
# Fix possible issue with saml namespace
if (!$decrypted->hasAttributeNS('http://www.w3.org/2000/xmlns/', 'xmlns:saml') && !$decrypted->hasAttributeNS('http://www.w3.org/2000/xmlns/', 'xmlns:saml2') && !$decrypted->hasAttributeNS('http://www.w3.org/2000/xmlns/', 'xmlns') && !$container->hasAttributeNS('http://www.w3.org/2000/xmlns/', 'xmlns:saml') && !$container->hasAttributeNS('http://www.w3.org/2000/xmlns/', 'xmlns:saml2')) {
if (strpos($encryptedAssertion->tagName, 'saml2:') !== false) {
$ns = 'xmlns:saml2';
} else {
if (strpos($encryptedAssertion->tagName, 'saml:') != false) {
$ns = 'xmlns:saml';
} else {
$ns = 'xmlns';
}
}
$decrypted->setAttributeNS('http://www.w3.org/2000/xmlns/', $ns, OneLogin_Saml2_Constants::NS_SAML);
}
$container->replaceChild($decrypted, $encryptedAssertion);
return $decrypted->ownerDocument;
}
}
/**
*
* @@dataProvider decryptFilesProvider
* @throws \Exception
*/
public function testDecrypt($testName, $testFile, $privKey)
{
$doc = new \DOMDocument();
$output = null;
$doc->load($testFile);
$objenc = new XMLSecEnc();
$encData = $objenc->locateEncryptedData($doc);
$this->assertInstanceOf('\\DOMElement', $encData, "Cannot locate Encrypted Data");
$objenc->setNode($encData);
$objenc->type = $encData->getAttribute("Type");
$objKey = $objenc->locateKey();
$this->assertInstanceOf('\\XmlSecLibs\\XMLSecurityKey', $objKey, "We know the secret key, but not the algorithm");
$key = null;
if ($objKeyInfo = $objenc->locateKeyInfo($objKey)) {
if ($objKeyInfo->isEncrypted) {
$objencKey = $objKeyInfo->encryptedCtx;
$objKeyInfo->loadKey($privKey, true);
$key = $objencKey->decryptKey($objKeyInfo);
}
}
if (!$objKey->key && empty($key)) {
$objKeyInfo->loadKey($privKey, true);
}
if (empty($objKey->key)) {
$objKey->loadKey($key);
}
$token = null;
if ($decrypt = $objenc->decryptNode($objKey, true)) {
$output = null;
if ($decrypt instanceof \DOMNode) {
if ($decrypt instanceof \DOMDocument) {
$output = $decrypt->saveXML();
} else {
$output = $decrypt->ownerDocument->saveXML();
}
} else {
$output = $decrypt;
}
}
$outfile = dirname(__FILE__) . "/../basic-doc.xml";
$res = null;
$this->assertFileExists($outfile);
$resDoc = new \DOMDocument();
$resDoc->load($outfile);
$res = $resDoc->saveXML();
$this->assertEquals($res, $output, "{$testName} Failed to decrypt {$testFile}");
}