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<?php
declare(strict_types=1);
/*
* The MIT License (MIT)
*
* Copyright (c) 2014-2018 Spomky-Labs
*
* This software may be modified and distributed under the terms
* of the MIT license. See the LICENSE file for details.
*/
namespace Jose\Component\Signature;
use Base64Url\Base64Url;
use Jose\Component\Core\AlgorithmManager;
use Jose\Component\Core\Converter\JsonConverter;
use Jose\Component\Core\JWK;
use Jose\Component\Core\Util\KeyChecker;
use Jose\Component\Signature\Algorithm\SignatureAlgorithm;
class JWSBuilder
{
/**
* @var JsonConverter
*/
private $jsonConverter;
/**
* @var string|null
*/
private $payload;
/**
* @var bool
*/
private $isPayloadDetached;
/**
* @var array
*/
private $signatures = [];
/**
* @var AlgorithmManager
*/
private $signatureAlgorithmManager;
/**
* @var bool|null
*/
private $isPayloadEncoded = null;
/**
* JWSBuilder constructor.
*/
public function __construct(?JsonConverter $jsonConverter, AlgorithmManager $signatureAlgorithmManager)
{
$this->jsonConverter = $jsonConverter ?? new \Jose\Component\Core\Util\JsonConverter();
$this->signatureAlgorithmManager = $signatureAlgorithmManager;
}
/**
* Returns the algorithm manager associated to the builder.
*/
public function getSignatureAlgorithmManager(): AlgorithmManager
{
return $this->signatureAlgorithmManager;
}
/**
* Reset the current data.
*
* @return JWSBuilder
*/
public function create(): self
{
$this->payload = null;
$this->isPayloadDetached = false;
$this->signatures = [];
$this->isPayloadEncoded = null;
return $this;
}
/**
* Set the payload.
* This method will return a new JWSBuilder object.
*
* @return JWSBuilder
*/
public function withPayload(string $payload, bool $isPayloadDetached = false): self
{
if (false === \mb_detect_encoding($payload, 'UTF-8', true)) {
throw new \InvalidArgumentException('The payload must be encoded in UTF-8');
}
$clone = clone $this;
$clone->payload = $payload;
$clone->isPayloadDetached = $isPayloadDetached;
return $clone;
}
/**
* Adds the information needed to compute the signature.
* This method will return a new JWSBuilder object.
*
* @return JWSBuilder
*/
public function addSignature(JWK $signatureKey, array $protectedHeader, array $header = []): self
{
$this->checkB64AndCriticalHeader($protectedHeader);
$isPayloadEncoded = $this->checkIfPayloadIsEncoded($protectedHeader);
if (null === $this->isPayloadEncoded) {
$this->isPayloadEncoded = $isPayloadEncoded;
} elseif ($this->isPayloadEncoded !== $isPayloadEncoded) {
throw new \InvalidArgumentException('Foreign payload encoding detected.');
}
$this->checkDuplicatedHeaderParameters($protectedHeader, $header);
KeyChecker::checkKeyUsage($signatureKey, 'signature');
$signatureAlgorithm = $this->findSignatureAlgorithm($signatureKey, $protectedHeader, $header);
KeyChecker::checkKeyAlgorithm($signatureKey, $signatureAlgorithm->name());
$clone = clone $this;
$clone->signatures[] = [
'signature_algorithm' => $signatureAlgorithm,
'signature_key' => $signatureKey,
'protected_header' => $protectedHeader,
'header' => $header,
];
return $clone;
}
/**
* Computes all signatures and return the expected JWS object.
*/
public function build(): JWS
{
if (null === $this->payload) {
throw new \RuntimeException('The payload is not set.');
}
if (0 === \count($this->signatures)) {
throw new \RuntimeException('At least one signature must be set.');
}
$encodedPayload = false === $this->isPayloadEncoded ? $this->payload : Base64Url::encode($this->payload);
$jws = JWS::create($this->payload, $encodedPayload, $this->isPayloadDetached);
foreach ($this->signatures as $signature) {
/** @var SignatureAlgorithm $signatureAlgorithm */
$signatureAlgorithm = $signature['signature_algorithm'];
/** @var JWK $signatureKey */
$signatureKey = $signature['signature_key'];
/** @var array $protectedHeader */
$protectedHeader = $signature['protected_header'];
/** @var array $header */
$header = $signature['header'];
$encodedProtectedHeader = empty($protectedHeader) ? null : Base64Url::encode($this->jsonConverter->encode($protectedHeader));
$input = \sprintf('%s.%s', $encodedProtectedHeader, $encodedPayload);
$s = $signatureAlgorithm->sign($signatureKey, $input);
$jws = $jws->addSignature($s, $protectedHeader, $encodedProtectedHeader, $header);
}
return $jws;
}
private function checkIfPayloadIsEncoded(array $protectedHeader): bool
{
return !\array_key_exists('b64', $protectedHeader) || true === $protectedHeader['b64'];
}
private function checkB64AndCriticalHeader(array $protectedHeader)
{
if (!\array_key_exists('b64', $protectedHeader)) {
return;
}
if (!\array_key_exists('crit', $protectedHeader)) {
throw new \LogicException('The protected header parameter "crit" is mandatory when protected header parameter "b64" is set.');
}
if (!\is_array($protectedHeader['crit'])) {
throw new \LogicException('The protected header parameter "crit" must be an array.');
}
if (!\in_array('b64', $protectedHeader['crit'], true)) {
throw new \LogicException('The protected header parameter "crit" must contain "b64" when protected header parameter "b64" is set.');
}
}
private function findSignatureAlgorithm(JWK $key, array $protectedHeader, array $header): SignatureAlgorithm
{
$completeHeader = \array_merge($header, $protectedHeader);
if (!\array_key_exists('alg', $completeHeader)) {
throw new \InvalidArgumentException('No "alg" parameter set in the header.');
}
if ($key->has('alg') && $key->get('alg') !== $completeHeader['alg']) {
throw new \InvalidArgumentException(\sprintf('The algorithm "%s" is not allowed with this key.', $completeHeader['alg']));
}
$signatureAlgorithm = $this->signatureAlgorithmManager->get($completeHeader['alg']);
if (!$signatureAlgorithm instanceof SignatureAlgorithm) {
throw new \InvalidArgumentException(\sprintf('The algorithm "%s" is not supported.', $completeHeader['alg']));
}
return $signatureAlgorithm;
}
private function checkDuplicatedHeaderParameters(array $header1, array $header2)
{
$inter = \array_intersect_key($header1, $header2);
if (!empty($inter)) {
throw new \InvalidArgumentException(\sprintf('The header contains duplicated entries: %s.', \implode(', ', \array_keys($inter))));
}
}
}
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