114 lines
3.7 KiB
PHP

<?php
namespace UglyRobot\Infinite_Uploads\Aws\Crypto;
use UglyRobot\Infinite_Uploads\GuzzleHttp\Psr7\StreamDecoratorTrait;
use LogicException;
use UglyRobot\Infinite_Uploads\Psr\Http\Message\StreamInterface;
use UglyRobot\Infinite_Uploads\Aws\Crypto\Cipher\CipherMethod;
/**
* @internal Represents a stream of data to be encrypted with a passed cipher.
*/
class AesEncryptingStream implements \UglyRobot\Infinite_Uploads\Aws\Crypto\AesStreamInterface
{
const BLOCK_SIZE = 16;
// 128 bits
use StreamDecoratorTrait;
/**
* @var string
*/
private $buffer = '';
/**
* @var CipherMethod
*/
private $cipherMethod;
/**
* @var string
*/
private $key;
/**
* @var StreamInterface
*/
private $stream;
/**
* @param StreamInterface $plainText
* @param string $key
* @param CipherMethod $cipherMethod
*/
public function __construct(\UglyRobot\Infinite_Uploads\Psr\Http\Message\StreamInterface $plainText, $key, \UglyRobot\Infinite_Uploads\Aws\Crypto\Cipher\CipherMethod $cipherMethod)
{
$this->stream = $plainText;
$this->key = $key;
$this->cipherMethod = clone $cipherMethod;
}
public function getOpenSslName()
{
return $this->cipherMethod->getOpenSslName();
}
public function getAesName()
{
return $this->cipherMethod->getAesName();
}
public function getCurrentIv()
{
return $this->cipherMethod->getCurrentIv();
}
public function getSize()
{
$plainTextSize = $this->stream->getSize();
if ($this->cipherMethod->requiresPadding() && $plainTextSize !== null) {
// PKCS7 padding requires that between 1 and self::BLOCK_SIZE be
// added to the plaintext to make it an even number of blocks.
$padding = self::BLOCK_SIZE - $plainTextSize % self::BLOCK_SIZE;
return $plainTextSize + $padding;
}
return $plainTextSize;
}
public function isWritable()
{
return false;
}
public function read($length)
{
if ($length > strlen($this->buffer)) {
$this->buffer .= $this->encryptBlock(self::BLOCK_SIZE * ceil(($length - strlen($this->buffer)) / self::BLOCK_SIZE));
}
$data = substr($this->buffer, 0, $length);
$this->buffer = substr($this->buffer, $length);
return $data ? $data : '';
}
public function seek($offset, $whence = SEEK_SET)
{
if ($whence === SEEK_CUR) {
$offset = $this->tell() + $offset;
$whence = SEEK_SET;
}
if ($whence === SEEK_SET) {
$this->buffer = '';
$wholeBlockOffset = (int) ($offset / self::BLOCK_SIZE) * self::BLOCK_SIZE;
$this->stream->seek($wholeBlockOffset);
$this->cipherMethod->seek($wholeBlockOffset);
$this->read($offset - $wholeBlockOffset);
} else {
throw new \LogicException('Unrecognized whence.');
}
}
private function encryptBlock($length)
{
if ($this->stream->eof()) {
return '';
}
$plainText = '';
do {
$plainText .= $this->stream->read($length - strlen($plainText));
} while (strlen($plainText) < $length && !$this->stream->eof());
$options = OPENSSL_RAW_DATA;
if (!$this->stream->eof() || $this->stream->getSize() !== $this->stream->tell()) {
$options |= OPENSSL_ZERO_PADDING;
}
$cipherText = openssl_encrypt($plainText, $this->cipherMethod->getOpenSslName(), $this->key, $options, $this->cipherMethod->getCurrentIv());
$this->cipherMethod->update($cipherText);
return $cipherText;
}
}