<?php
namespace Aws\S3\Crypto;
use Aws\Crypto\DecryptionTraitV2;
use Aws\Exception\CryptoException;
use Aws\HashingStream;
use Aws\PhpHash;
use Aws\Crypto\AbstractCryptoClientV2;
use Aws\Crypto\EncryptionTraitV2;
use Aws\Crypto\MetadataEnvelope;
use Aws\Crypto\MaterialsProvider;
use Aws\Crypto\Cipher\CipherBuilderTrait;
use Aws\S3\S3Client;
use GuzzleHttp\Promise;
use GuzzleHttp\Promise\PromiseInterface;
use GuzzleHttp\Psr7;
/**
* Provides a wrapper for an S3Client that supplies functionality to encrypt
* data on putObject[Async] calls and decrypt data on getObject[Async] calls.
*
* AWS strongly recommends the upgrade to the S3EncryptionClientV2 (over the
* S3EncryptionClient), as it offers updated data security best practices to our
* customers who upgrade. S3EncryptionClientV2 contains breaking changes, so this
* will require planning by engineering teams to migrate. New workflows should
* just start with S3EncryptionClientV2.
*
* Note that for PHP versions of < 7.1, this class uses an AES-GCM polyfill
* for encryption since there is no native PHP support. The performance for large
* inputs will be a lot slower than for PHP 7.1+, so upgrading older PHP version
* environments may be necessary to use this effectively.
*
* Example write path:
*
* <code>
* use Aws\Crypto\KmsMaterialsProviderV2;
* use Aws\S3\Crypto\S3EncryptionClientV2;
* use Aws\S3\S3Client;
*
* $encryptionClient = new S3EncryptionClientV2(
* new S3Client([
* 'region' => 'us-west-2',
* 'version' => 'latest'
* ])
* );
* $materialsProvider = new KmsMaterialsProviderV2(
* new KmsClient([
* 'profile' => 'default',
* 'region' => 'us-east-1',
* 'version' => 'latest',
* ],
* 'your-kms-key-id'
* );
*
* $encryptionClient->putObject([
* '@MaterialsProvider' => $materialsProvider,
* '@CipherOptions' => [
* 'Cipher' => 'gcm',
* 'KeySize' => 256,
* ],
* '@KmsEncryptionContext' => ['foo' => 'bar'],
* 'Bucket' => 'your-bucket',
* 'Key' => 'your-key',
* 'Body' => 'your-encrypted-data',
* ]);
* </code>
*
* Example read call (using objects from previous example):
*
* <code>
* $encryptionClient->getObject([
* '@MaterialsProvider' => $materialsProvider,
* '@CipherOptions' => [
* 'Cipher' => 'gcm',
* 'KeySize' => 256,
* ],
* 'Bucket' => 'your-bucket',
* 'Key' => 'your-key',
* ]);
* </code>
*/
class S3EncryptionClientV2 extends AbstractCryptoClientV2
{
use CipherBuilderTrait;
use CryptoParamsTraitV2;
use DecryptionTraitV2;
use EncryptionTraitV2;
use UserAgentTrait;
const CRYPTO_VERSION = '2.1';
private $client;
private $instructionFileSuffix;
private $legacyWarningCount;
/**
* @param S3Client $client The S3Client to be used for true uploading and
* retrieving objects from S3 when using the
* encryption client.
* @param string|null $instructionFileSuffix Suffix for a client wide
* default when using instruction
* files for metadata storage.
*/
public function __construct(
S3Client $client,
$instructionFileSuffix = null
) {
$this->appendUserAgent($client, 'feat/s3-encrypt/' . self::CRYPTO_VERSION);
$this->client = $client;
$this->instructionFileSuffix = $instructionFileSuffix;
$this->legacyWarningCount = 0;
}
private static function getDefaultStrategy()
{
return new HeadersMetadataStrategy();
}
/**
* Encrypts the data in the 'Body' field of $args and promises to upload it
* to the specified location on S3.
*
* Note that for PHP versions of < 7.1, this operation uses an AES-GCM
* polyfill for encryption since there is no native PHP support. The
* performance for large inputs will be a lot slower than for PHP 7.1+, so
* upgrading older PHP version environments may be necessary to use this
* effectively.
*
* @param array $args Arguments for encrypting an object and uploading it
* to S3 via PutObject.
*
* The required configuration arguments are as follows:
*
* - @MaterialsProvider: (MaterialsProviderV2) Provides Cek, Iv, and Cek
* encrypting/decrypting for encryption metadata.
* - @CipherOptions: (array) Cipher options for encrypting data. Only the
* Cipher option is required. Accepts the following:
* - Cipher: (string) gcm
* See also: AbstractCryptoClientV2::$supportedCiphers
* - KeySize: (int) 128|256
* See also: MaterialsProvider::$supportedKeySizes
* - Aad: (string) Additional authentication data. This option is
* passed directly to OpenSSL when using gcm. Note if you pass in
* Aad, the PHP SDK will be able to decrypt the resulting object,
* but other AWS SDKs may not be able to do so.
* - @KmsEncryptionContext: (array) Only required if using
* KmsMaterialsProviderV2. An associative array of key-value
* pairs to be added to the encryption context for KMS key encryption. An
* empty array may be passed if no additional context is desired.
*
* The optional configuration arguments are as follows:
*
* - @MetadataStrategy: (MetadataStrategy|string|null) Strategy for storing
* MetadataEnvelope information. Defaults to using a
* HeadersMetadataStrategy. Can either be a class implementing
* MetadataStrategy, a class name of a predefined strategy, or empty/null
* to default.
* - @InstructionFileSuffix: (string|null) Suffix used when writing to an
* instruction file if using an InstructionFileMetadataHandler.
*
* @return PromiseInterface
*
* @throws \InvalidArgumentException Thrown when arguments above are not
* passed or are passed incorrectly.
*/
public function putObjectAsync(array $args)
{
$provider = $this->getMaterialsProvider($args);
unset($args['@MaterialsProvider']);
$instructionFileSuffix = $this->getInstructionFileSuffix($args);
unset($args['@InstructionFileSuffix']);
$strategy = $this->getMetadataStrategy($args, $instructionFileSuffix);
unset($args['@MetadataStrategy']);
$envelope = new MetadataEnvelope();
return Promise\promise_for($this->encrypt(
Psr7\Utils::streamFor($args['Body']),
$args,
$provider,
$envelope
))->then(
function ($encryptedBodyStream) use ($args) {
$hash = new PhpHash('sha256');
$hashingEncryptedBodyStream = new HashingStream(
$encryptedBodyStream,
$hash,
self::getContentShaDecorator($args)
);
return [$hashingEncryptedBodyStream, $args];
}
)->then(
function ($putObjectContents) use ($strategy, $envelope) {
list($bodyStream, $args) = $putObjectContents;
if ($strategy === null) {
$strategy = self::getDefaultStrategy();
}
$updatedArgs = $strategy->save($envelope, $args);
$updatedArgs['Body'] = $bodyStream;
return $updatedArgs;
}
)->then(
function ($args) {
unset($args['@CipherOptions']);
return $this->client->putObjectAsync($args);
}
);
}
private static function getContentShaDecorator(&$args)
{
return function ($hash) use (&$args) {
$args['ContentSHA256'] = bin2hex($hash);
};
}
/**
* Encrypts the data in the 'Body' field of $args and uploads it to the
* specified location on S3.
*
* Note that for PHP versions of < 7.1, this operation uses an AES-GCM
* polyfill for encryption since there is no native PHP support. The
* performance for large inputs will be a lot slower than for PHP 7.1+, so
* upgrading older PHP version environments may be necessary to use this
* effectively.
*
* @param array $args Arguments for encrypting an object and uploading it
* to S3 via PutObject.
*
* The required configuration arguments are as follows:
*
* - @MaterialsProvider: (MaterialsProvider) Provides Cek, Iv, and Cek
* encrypting/decrypting for encryption metadata.
* - @CipherOptions: (array) Cipher options for encrypting data. A Cipher
* is required. Accepts the following options:
* - Cipher: (string) gcm
* See also: AbstractCryptoClientV2::$supportedCiphers
* - KeySize: (int) 128|256
* See also: MaterialsProvider::$supportedKeySizes
* - Aad: (string) Additional authentication data. This option is
* passed directly to OpenSSL when using gcm. Note if you pass in
* Aad, the PHP SDK will be able to decrypt the resulting object,
* but other AWS SDKs may not be able to do so.
* - @KmsEncryptionContext: (array) Only required if using
* KmsMaterialsProviderV2. An associative array of key-value
* pairs to be added to the encryption context for KMS key encryption. An
* empty array may be passed if no additional context is desired.
*
* The optional configuration arguments are as follows:
*
* - @MetadataStrategy: (MetadataStrategy|string|null) Strategy for storing
* MetadataEnvelope information. Defaults to using a
* HeadersMetadataStrategy. Can either be a class implementing
* MetadataStrategy, a class name of a predefined strategy, or empty/null
* to default.
* - @InstructionFileSuffix: (string|null) Suffix used when writing to an
* instruction file if an using an InstructionFileMetadataHandler was
* determined.
*
* @return \Aws\Result PutObject call result with the details of uploading
* the encrypted file.
*
* @throws \InvalidArgumentException Thrown when arguments above are not
* passed or are passed incorrectly.
*/
public function putObject(array $args)
{
return $this->putObjectAsync($args)->wait();
}
/**
* Promises to retrieve an object from S3 and decrypt the data in the
* 'Body' field.
*
* @param array $args Arguments for retrieving an object from S3 via
* GetObject and decrypting it.
*
* The required configuration argument is as follows:
*
* - @MaterialsProvider: (MaterialsProviderInterface) Provides Cek, Iv, and Cek
* encrypting/decrypting for decryption metadata. May have data loaded
* from the MetadataEnvelope upon decryption.
* - @SecurityProfile: (string) Must be set to 'V2' or 'V2_AND_LEGACY'.
* - 'V2' indicates that only objects encrypted with S3EncryptionClientV2
* content encryption and key wrap schemas are able to be decrypted.
* - 'V2_AND_LEGACY' indicates that objects encrypted with both
* S3EncryptionClientV2 and older legacy encryption clients are able
* to be decrypted.
*
* The optional configuration arguments are as follows:
*
* - SaveAs: (string) The path to a file on disk to save the decrypted
* object data. This will be handled by file_put_contents instead of the
* Guzzle sink.
*
* - @MetadataStrategy: (MetadataStrategy|string|null) Strategy for reading
* MetadataEnvelope information. Defaults to determining based on object
* response headers. Can either be a class implementing MetadataStrategy,
* a class name of a predefined strategy, or empty/null to default.
* - @InstructionFileSuffix: (string) Suffix used when looking for an
* instruction file if an InstructionFileMetadataHandler is being used.
* - @CipherOptions: (array) Cipher options for decrypting data. A Cipher
* is required. Accepts the following options:
* - Aad: (string) Additional authentication data. This option is
* passed directly to OpenSSL when using gcm. It is ignored when
* using cbc.
* - @KmsAllowDecryptWithAnyCmk: (bool) This allows decryption with
* KMS materials for any KMS key ID, instead of needing the KMS key ID to
* be specified and provided to the decrypt operation. Ignored for non-KMS
* materials providers. Defaults to false.
*
* @return PromiseInterface
*
* @throws \InvalidArgumentException Thrown when required arguments are not
* passed or are passed incorrectly.
*/
public function getObjectAsync(array $args)
{
$provider = $this->getMaterialsProvider($args);
unset($args['@MaterialsProvider']);
$instructionFileSuffix = $this->getInstructionFileSuffix($args);
unset($args['@InstructionFileSuffix']);
$strategy = $this->getMetadataStrategy($args, $instructionFileSuffix);
unset($args['@MetadataStrategy']);
if (!isset($args['@SecurityProfile'])
|| !in_array($args['@SecurityProfile'], self::$supportedSecurityProfiles)
) {
throw new CryptoException("@SecurityProfile is required and must be"
. " set to 'V2' or 'V2_AND_LEGACY'");
}
// Only throw this legacy warning once per client
if (in_array($args['@SecurityProfile'], self::$legacySecurityProfiles)
&& $this->legacyWarningCount < 1
) {
$this->legacyWarningCount++;
trigger_error(
"This S3 Encryption Client operation is configured to"
. " read encrypted data with legacy encryption modes. If you"
. " don't have objects encrypted with these legacy modes,"
. " you should disable support for them to enhance security. ",
E_USER_WARNING
);
}
$saveAs = null;
if (!empty($args['SaveAs'])) {
$saveAs = $args['SaveAs'];
}
$promise = $this->client->getObjectAsync($args)
->then(
function ($result) use (
$provider,
$instructionFileSuffix,
$strategy,
$args
) {
if ($strategy === null) {
$strategy = $this->determineGetObjectStrategy(
$result,
$instructionFileSuffix
);
}
$envelope = $strategy->load($args + [
'Metadata' => $result['Metadata']
]);
$result['Body'] = $this->decrypt(
$result['Body'],
$provider,
$envelope,
$args
);
return $result;
}
)->then(
function ($result) use ($saveAs) {
if (!empty($saveAs)) {
file_put_contents(
$saveAs,
(string)$result['Body'],
LOCK_EX
);
}
return $result;
}
);
return $promise;
}
/**
* Retrieves an object from S3 and decrypts the data in the 'Body' field.
*
* @param array $args Arguments for retrieving an object from S3 via
* GetObject and decrypting it.
*
* The required configuration argument is as follows:
*
* - @MaterialsProvider: (MaterialsProviderInterface) Provides Cek, Iv, and Cek
* encrypting/decrypting for decryption metadata. May have data loaded
* from the MetadataEnvelope upon decryption.
* - @SecurityProfile: (string) Must be set to 'V2' or 'V2_AND_LEGACY'.
* - 'V2' indicates that only objects encrypted with S3EncryptionClientV2
* content encryption and key wrap schemas are able to be decrypted.
* - 'V2_AND_LEGACY' indicates that objects encrypted with both
* S3EncryptionClientV2 and older legacy encryption clients are able
* to be decrypted.
*
* The optional configuration arguments are as follows:
*
* - SaveAs: (string) The path to a file on disk to save the decrypted
* object data. This will be handled by file_put_contents instead of the
* Guzzle sink.
* - @InstructionFileSuffix: (string|null) Suffix used when looking for an
* instruction file if an InstructionFileMetadataHandler was detected.
* - @CipherOptions: (array) Cipher options for encrypting data. A Cipher
* is required. Accepts the following options:
* - Aad: (string) Additional authentication data. This option is
* passed directly to OpenSSL when using gcm. It is ignored when
* using cbc.
* - @KmsAllowDecryptWithAnyCmk: (bool) This allows decryption with
* KMS materials for any KMS key ID, instead of needing the KMS key ID to
* be specified and provided to the decrypt operation. Ignored for non-KMS
* materials providers. Defaults to false.
*
* @return \Aws\Result GetObject call result with the 'Body' field
* wrapped in a decryption stream with its metadata
* information.
*
* @throws \InvalidArgumentException Thrown when arguments above are not
* passed or are passed incorrectly.
*/
public function getObject(array $args)
{
return $this->getObjectAsync($args)->wait();
}
}