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<?php |
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declare(strict_types=1); |
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namespace SimpleSAML\XMLSecurity\XML; |
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use SimpleSAML\XMLSecurity\Alg\Encryption\EncryptionAlgorithmFactory; |
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use SimpleSAML\XMLSecurity\Alg\Encryption\EncryptionAlgorithmInterface; |
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use SimpleSAML\XMLSecurity\Backend\EncryptionBackend; |
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use SimpleSAML\XMLSecurity\Constants as C; |
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use SimpleSAML\XMLSecurity\Exception\InvalidArgumentException; |
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use SimpleSAML\XMLSecurity\Exception\NoEncryptedDataException; |
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use SimpleSAML\XMLSecurity\Exception\RuntimeException; |
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use SimpleSAML\XMLSecurity\Key\SymmetricKey; |
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use SimpleSAML\XMLSecurity\XML\xenc\EncryptedData; |
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use SimpleSAML\XMLSecurity\XML\xenc\EncryptedKey; |
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use function base64_decode; |
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/** |
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* Trait aggregating functionality for encrypted elements. |
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* |
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* @package simplesamlphp/xml-security |
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*/ |
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trait EncryptedElementTrait |
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{ |
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/** @var \SimpleSAML\XMLSecurity\XML\xenc\EncryptedKey|null */ |
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protected ?EncryptedKey $encryptedKey = null; |
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/** |
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* Constructor for encrypted elements. |
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* |
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* @param \SimpleSAML\XMLSecurity\XML\xenc\EncryptedData $encryptedData The EncryptedData object. |
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*/ |
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public function __construct( |
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protected EncryptedData $encryptedData, |
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) { |
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$keyInfo = $this->encryptedData->getKeyInfo(); |
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if ($keyInfo === null) { |
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return; |
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} |
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foreach ($keyInfo->getInfo() as $info) { |
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if ($info instanceof EncryptedKey) { |
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$this->encryptedKey = $info; |
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} |
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} |
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} |
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/** |
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* Whether the encrypted object is accompanied by the decryption key or not. |
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* |
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* @return bool |
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*/ |
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public function hasDecryptionKey(): bool |
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{ |
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return $this->encryptedKey !== null; |
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} |
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/** |
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* Get the encrypted key used to encrypt the current element. |
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* |
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* @return \SimpleSAML\XMLSecurity\XML\xenc\EncryptedKey |
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*/ |
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public function getEncryptedKey(): EncryptedKey |
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{ |
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return $this->encryptedKey; |
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} |
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/** |
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* Get the EncryptedData object. |
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* |
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* @return \SimpleSAML\XMLSecurity\XML\xenc\EncryptedData |
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*/ |
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public function getEncryptedData(): EncryptedData |
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{ |
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return $this->encryptedData; |
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} |
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/** |
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* Decrypt the data in any given element. |
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* |
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* Use this method to decrypt an EncryptedData XML elemento into a string. If the resulting plaintext represents |
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* an XML document which has a corresponding implementation extending \SimpleSAML\XML\ElementInterface, you |
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* can call this method to build an object from the resulting plaintext: |
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* |
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* $data = $this->decryptData($decryptor); |
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* $xml = \SimpleSAML\XML\DOMDocumentFactory::fromString($data); |
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* $object = MyObject::fromXML($xml->documentElement); |
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* |
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* If the class using this trait implements \SimpleSAML\XMLSecurity\XML\EncryptedElementInterface, then the |
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* decrypt() method will only need the proposed code and return the object. |
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* |
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* @param \SimpleSAML\XMLSecurity\Alg\Encryption\EncryptionAlgorithmInterface $decryptor The decryptor to use to |
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* decrypt the object. |
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* |
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* @return string The decrypted data. |
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*/ |
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protected function decryptData(EncryptionAlgorithmInterface $decryptor): string |
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{ |
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$encData = $this->getEncryptedData(); |
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if (!$encData instanceof EncryptedData) { |
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throw new NoEncryptedDataException(); |
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} |
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$algId = $decryptor->getAlgorithmId(); |
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$encMethod = $this->getEncryptedData()->getEncryptionMethod(); |
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if ($encMethod !== null) { |
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$algId = $encMethod->getAlgorithm(); |
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} |
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if (in_array($decryptor->getAlgorithmId(), C::$KEY_TRANSPORT_ALGORITHMS)) { |
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// the decryptor uses a key transport algorithm, check if we have a session key |
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if ($this->hasDecryptionKey() === null) { |
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throw new RuntimeException('Cannot use a key transport algorithm to decrypt an object.'); |
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} |
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if ($encMethod === null) { |
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throw new RuntimeException('Cannot decrypt data with a session key and no EncryptionMethod.'); |
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} |
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$encryptedKey = $this->getEncryptedKey(); |
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$decryptionKey = $encryptedKey->decrypt($decryptor); |
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$factory = new EncryptionAlgorithmFactory($this->getBlacklistedAlgorithms()); |
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$decryptor = $factory->getAlgorithm($encMethod->getAlgorithm(), new SymmetricKey($decryptionKey)); |
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$decryptor->setBackend($this->getEncryptionBackend()); |
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} |
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if ($algId !== $decryptor->getAlgorithmId()) { |
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throw new InvalidArgumentException('Decryption algorithm does not match EncryptionMethod.'); |
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} |
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return $decryptor->decrypt(base64_decode($encData->getCipherData()->getCipherValue()->getContent())); |
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} |
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/** |
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* Get the encryption backend to use for any encryption operation. |
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* |
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* @return \SimpleSAML\XMLSecurity\Backend\EncryptionBackend|null The encryption backend to use, or null if we |
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* want to use the default. |
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*/ |
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abstract public function getEncryptionBackend(): ?EncryptionBackend; |
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/** |
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* Get the list of algorithms that are blacklisted for any encryption operation. |
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* |
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* @return string[]|null An array with all algorithm identifiers that are blacklisted, or null if we want to use the |
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* defaults. |
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*/ |
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abstract public function getBlacklistedAlgorithms(): ?array; |
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} |
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