123 lines
7.0 KiB
PHP

<?php
namespace UglyRobot\Infinite_Uploads\Aws\Crypto;
use UglyRobot\Infinite_Uploads\GuzzleHttp\Psr7;
use UglyRobot\Infinite_Uploads\GuzzleHttp\Psr7\AppendStream;
use UglyRobot\Infinite_Uploads\GuzzleHttp\Psr7\Stream;
use UglyRobot\Infinite_Uploads\Psr\Http\Message\StreamInterface;
trait EncryptionTraitV2
{
private static $allowedOptions = ['Cipher' => true, 'KeySize' => true, 'Aad' => true];
private static $encryptClasses = ['gcm' => \UglyRobot\Infinite_Uploads\Aws\Crypto\AesGcmEncryptingStream::class];
/**
* Dependency to generate a CipherMethod from a set of inputs for loading
* in to an AesEncryptingStream.
*
* @param string $cipherName Name of the cipher to generate for encrypting.
* @param string $iv Base Initialization Vector for the cipher.
* @param int $keySize Size of the encryption key, in bits, that will be
* used.
*
* @return Cipher\CipherMethod
*
* @internal
*/
protected abstract function buildCipherMethod($cipherName, $iv, $keySize);
/**
* Builds an AesStreamInterface and populates encryption metadata into the
* supplied envelope.
*
* @param Stream $plaintext Plain-text data to be encrypted using the
* materials, algorithm, and data provided.
* @param array $options Options for use in encryption, including cipher
* options, and encryption context.
* @param MaterialsProviderV2 $provider A provider to supply and encrypt
* materials used in encryption.
* @param MetadataEnvelope $envelope A storage envelope for encryption
* metadata to be added to.
*
* @return StreamInterface
*
* @throws \InvalidArgumentException Thrown when a value in $options['@CipherOptions']
* is not valid.
*s
* @internal
*/
public function encrypt(\UglyRobot\Infinite_Uploads\GuzzleHttp\Psr7\Stream $plaintext, array $options, \UglyRobot\Infinite_Uploads\Aws\Crypto\MaterialsProviderV2 $provider, \UglyRobot\Infinite_Uploads\Aws\Crypto\MetadataEnvelope $envelope)
{
$options = array_change_key_case($options);
$cipherOptions = array_intersect_key($options['@cipheroptions'], self::$allowedOptions);
if (empty($cipherOptions['Cipher'])) {
throw new \InvalidArgumentException('An encryption cipher must be' . ' specified in @CipherOptions["Cipher"].');
}
$cipherOptions['Cipher'] = strtolower($cipherOptions['Cipher']);
if (!self::isSupportedCipher($cipherOptions['Cipher'])) {
throw new \InvalidArgumentException('The cipher requested is not' . ' supported by the SDK.');
}
if (empty($cipherOptions['KeySize'])) {
$cipherOptions['KeySize'] = 256;
}
if (!is_int($cipherOptions['KeySize'])) {
throw new \InvalidArgumentException('The cipher "KeySize" must be' . ' an integer.');
}
if (!\UglyRobot\Infinite_Uploads\Aws\Crypto\MaterialsProviderV2::isSupportedKeySize($cipherOptions['KeySize'])) {
throw new \InvalidArgumentException('The cipher "KeySize" requested' . ' is not supported by AES (128 or 256).');
}
$cipherOptions['Iv'] = $provider->generateIv($this->getCipherOpenSslName($cipherOptions['Cipher'], $cipherOptions['KeySize']));
$encryptClass = self::$encryptClasses[$cipherOptions['Cipher']];
$aesName = $encryptClass::getStaticAesName();
$materialsDescription = ['aws:x-amz-cek-alg' => $aesName];
$keys = $provider->generateCek($cipherOptions['KeySize'], $materialsDescription, $options);
// Some providers modify materials description based on options
if (isset($keys['UpdatedContext'])) {
$materialsDescription = $keys['UpdatedContext'];
}
$encryptingStream = $this->getEncryptingStream($plaintext, $keys['Plaintext'], $cipherOptions);
// Populate envelope data
$envelope[\UglyRobot\Infinite_Uploads\Aws\Crypto\MetadataEnvelope::CONTENT_KEY_V2_HEADER] = $keys['Ciphertext'];
unset($keys);
$envelope[\UglyRobot\Infinite_Uploads\Aws\Crypto\MetadataEnvelope::IV_HEADER] = base64_encode($cipherOptions['Iv']);
$envelope[\UglyRobot\Infinite_Uploads\Aws\Crypto\MetadataEnvelope::KEY_WRAP_ALGORITHM_HEADER] = $provider->getWrapAlgorithmName();
$envelope[\UglyRobot\Infinite_Uploads\Aws\Crypto\MetadataEnvelope::CONTENT_CRYPTO_SCHEME_HEADER] = $aesName;
$envelope[\UglyRobot\Infinite_Uploads\Aws\Crypto\MetadataEnvelope::UNENCRYPTED_CONTENT_LENGTH_HEADER] = strlen($plaintext);
$envelope[\UglyRobot\Infinite_Uploads\Aws\Crypto\MetadataEnvelope::MATERIALS_DESCRIPTION_HEADER] = json_encode($materialsDescription);
if (!empty($cipherOptions['Tag'])) {
$envelope[\UglyRobot\Infinite_Uploads\Aws\Crypto\MetadataEnvelope::CRYPTO_TAG_LENGTH_HEADER] = strlen($cipherOptions['Tag']) * 8;
}
return $encryptingStream;
}
/**
* Generates a stream that wraps the plaintext with the proper cipher and
* uses the content encryption key (CEK) to encrypt the data when read.
*
* @param Stream $plaintext Plain-text data to be encrypted using the
* materials, algorithm, and data provided.
* @param string $cek A content encryption key for use by the stream for
* encrypting the plaintext data.
* @param array $cipherOptions Options for use in determining the cipher to
* be used for encrypting data.
*
* @return [AesStreamInterface, string]
*
* @internal
*/
protected function getEncryptingStream(\UglyRobot\Infinite_Uploads\GuzzleHttp\Psr7\Stream $plaintext, $cek, &$cipherOptions)
{
switch ($cipherOptions['Cipher']) {
// Only 'gcm' is supported for encryption currently
case 'gcm':
$cipherOptions['TagLength'] = 16;
$encryptClass = self::$encryptClasses['gcm'];
$cipherTextStream = new $encryptClass($plaintext, $cek, $cipherOptions['Iv'], $cipherOptions['Aad'] = isset($cipherOptions['Aad']) ? $cipherOptions['Aad'] : '', $cipherOptions['TagLength'], $cipherOptions['KeySize']);
if (!empty($cipherOptions['Aad'])) {
trigger_error("'Aad' has been supplied for content encryption" . " with " . $cipherTextStream->getAesName() . ". The" . " PHP SDK encryption client can decrypt an object" . " encrypted in this way, but other AWS SDKs may not be" . " able to.", E_USER_WARNING);
}
$appendStream = new \UglyRobot\Infinite_Uploads\GuzzleHttp\Psr7\AppendStream([$cipherTextStream->createStream()]);
$cipherOptions['Tag'] = $cipherTextStream->getTag();
$appendStream->addStream(\UglyRobot\Infinite_Uploads\GuzzleHttp\Psr7\stream_for($cipherOptions['Tag']));
return $appendStream;
}
}
}