115 lines
6.7 KiB
PHP
115 lines
6.7 KiB
PHP
<?php
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namespace UglyRobot\Infinite_Uploads\Aws\Crypto;
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use UglyRobot\Infinite_Uploads\GuzzleHttp\Psr7;
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use UglyRobot\Infinite_Uploads\GuzzleHttp\Psr7\AppendStream;
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use UglyRobot\Infinite_Uploads\GuzzleHttp\Psr7\Stream;
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trait EncryptionTrait
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{
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private static $allowedOptions = ['Cipher' => true, 'KeySize' => true, 'Aad' => true];
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/**
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* Dependency to generate a CipherMethod from a set of inputs for loading
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* in to an AesEncryptingStream.
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*
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* @param string $cipherName Name of the cipher to generate for encrypting.
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* @param string $iv Base Initialization Vector for the cipher.
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* @param int $keySize Size of the encryption key, in bits, that will be
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* used.
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*
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* @return Cipher\CipherMethod
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*
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* @internal
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*/
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protected abstract function buildCipherMethod($cipherName, $iv, $keySize);
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/**
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* Builds an AesStreamInterface and populates encryption metadata into the
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* supplied envelope.
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*
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* @param Stream $plaintext Plain-text data to be encrypted using the
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* materials, algorithm, and data provided.
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* @param array $cipherOptions Options for use in determining the cipher to
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* be used for encrypting data.
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* @param MaterialsProvider $provider A provider to supply and encrypt
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* materials used in encryption.
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* @param MetadataEnvelope $envelope A storage envelope for encryption
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* metadata to be added to.
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*
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* @return AesStreamInterface
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*
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* @throws \InvalidArgumentException Thrown when a value in $cipherOptions
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* is not valid.
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*
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* @internal
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*/
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public function encrypt(\UglyRobot\Infinite_Uploads\GuzzleHttp\Psr7\Stream $plaintext, array $cipherOptions, \UglyRobot\Infinite_Uploads\Aws\Crypto\MaterialsProvider $provider, \UglyRobot\Infinite_Uploads\Aws\Crypto\MetadataEnvelope $envelope)
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{
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$materialsDescription = $provider->getMaterialsDescription();
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$cipherOptions = array_intersect_key($cipherOptions, self::$allowedOptions);
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if (empty($cipherOptions['Cipher'])) {
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throw new \InvalidArgumentException('An encryption cipher must be' . ' specified in the "cipher_options".');
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}
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if (!self::isSupportedCipher($cipherOptions['Cipher'])) {
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throw new \InvalidArgumentException('The cipher requested is not' . ' supported by the SDK.');
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}
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if (empty($cipherOptions['KeySize'])) {
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$cipherOptions['KeySize'] = 256;
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}
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if (!is_int($cipherOptions['KeySize'])) {
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throw new \InvalidArgumentException('The cipher "KeySize" must be' . ' an integer.');
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}
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if (!\UglyRobot\Infinite_Uploads\Aws\Crypto\MaterialsProvider::isSupportedKeySize($cipherOptions['KeySize'])) {
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throw new \InvalidArgumentException('The cipher "KeySize" requested' . ' is not supported by AES (128, 192, or 256).');
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}
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$cipherOptions['Iv'] = $provider->generateIv($this->getCipherOpenSslName($cipherOptions['Cipher'], $cipherOptions['KeySize']));
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$cek = $provider->generateCek($cipherOptions['KeySize']);
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list($encryptingStream, $aesName) = $this->getEncryptingStream($plaintext, $cek, $cipherOptions);
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// Populate envelope data
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$envelope[\UglyRobot\Infinite_Uploads\Aws\Crypto\MetadataEnvelope::CONTENT_KEY_V2_HEADER] = $provider->encryptCek($cek, $materialsDescription);
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unset($cek);
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$envelope[\UglyRobot\Infinite_Uploads\Aws\Crypto\MetadataEnvelope::IV_HEADER] = base64_encode($cipherOptions['Iv']);
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$envelope[\UglyRobot\Infinite_Uploads\Aws\Crypto\MetadataEnvelope::KEY_WRAP_ALGORITHM_HEADER] = $provider->getWrapAlgorithmName();
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$envelope[\UglyRobot\Infinite_Uploads\Aws\Crypto\MetadataEnvelope::CONTENT_CRYPTO_SCHEME_HEADER] = $aesName;
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$envelope[\UglyRobot\Infinite_Uploads\Aws\Crypto\MetadataEnvelope::UNENCRYPTED_CONTENT_LENGTH_HEADER] = strlen($plaintext);
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$envelope[\UglyRobot\Infinite_Uploads\Aws\Crypto\MetadataEnvelope::MATERIALS_DESCRIPTION_HEADER] = json_encode($materialsDescription);
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if (!empty($cipherOptions['Tag'])) {
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$envelope[\UglyRobot\Infinite_Uploads\Aws\Crypto\MetadataEnvelope::CRYPTO_TAG_LENGTH_HEADER] = strlen($cipherOptions['Tag']) * 8;
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}
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return $encryptingStream;
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}
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/**
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* Generates a stream that wraps the plaintext with the proper cipher and
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* uses the content encryption key (CEK) to encrypt the data when read.
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*
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* @param Stream $plaintext Plain-text data to be encrypted using the
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* materials, algorithm, and data provided.
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* @param string $cek A content encryption key for use by the stream for
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* encrypting the plaintext data.
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* @param array $cipherOptions Options for use in determining the cipher to
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* be used for encrypting data.
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*
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* @return [AesStreamInterface, string]
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*
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* @internal
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*/
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protected function getEncryptingStream(\UglyRobot\Infinite_Uploads\GuzzleHttp\Psr7\Stream $plaintext, $cek, &$cipherOptions)
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{
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switch ($cipherOptions['Cipher']) {
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case 'gcm':
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$cipherOptions['TagLength'] = 16;
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$cipherTextStream = new \UglyRobot\Infinite_Uploads\Aws\Crypto\AesGcmEncryptingStream($plaintext, $cek, $cipherOptions['Iv'], $cipherOptions['Aad'] = isset($cipherOptions['Aad']) ? $cipherOptions['Aad'] : null, $cipherOptions['TagLength'], $cipherOptions['KeySize']);
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if (!empty($cipherOptions['Aad'])) {
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trigger_error("'Aad' has been supplied for content encryption" . " with " . $cipherTextStream->getAesName() . ". The" . " PHP SDK encryption client can decrypt an object" . " encrypted in this way, but other AWS SDKs may not be" . " able to.", E_USER_WARNING);
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}
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$appendStream = new \UglyRobot\Infinite_Uploads\GuzzleHttp\Psr7\AppendStream([$cipherTextStream->createStream()]);
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$cipherOptions['Tag'] = $cipherTextStream->getTag();
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$appendStream->addStream(\UglyRobot\Infinite_Uploads\GuzzleHttp\Psr7\stream_for($cipherOptions['Tag']));
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return [$appendStream, $cipherTextStream->getAesName()];
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default:
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$cipherMethod = $this->buildCipherMethod($cipherOptions['Cipher'], $cipherOptions['Iv'], $cipherOptions['KeySize']);
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$cipherTextStream = new \UglyRobot\Infinite_Uploads\Aws\Crypto\AesEncryptingStream($plaintext, $cek, $cipherMethod);
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return [$cipherTextStream, $cipherTextStream->getAesName()];
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}
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}
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}
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