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<?php |
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declare(strict_types=1); |
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namespace SimpleSAML\XMLSecurity\Alg\Signature; |
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use SimpleSAML\Assert\Assert; |
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use SimpleSAML\XMLSecurity\Alg\SignatureAlgorithm; |
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use SimpleSAML\XMLSecurity\Constants; |
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use SimpleSAML\XMLSecurity\Exception\InvalidArgumentException; |
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use SimpleSAML\XMLSecurity\Key\AbstractKey; |
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use function in_array; |
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/** |
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* Factory class to create and configure digital signature algorithms. |
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* |
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* @package simplesamlphp/xml-security |
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*/ |
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final class SignatureAlgorithmFactory |
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{ |
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/** |
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* An array holding the known classes extending \SimpleSAML\XMLSecurity\Alg\Signature\AbstractSigner. |
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* |
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* @var string[] |
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*/ |
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private static array $algorithms = [ |
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RSA::class, |
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HMAC::class |
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]; |
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/** |
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* An array of blacklisted algorithms. |
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* |
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* Defaults to RSA-SHA1 & HMAC-SHA1 due to the weakness of SHA1. |
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* |
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* @var string[] |
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*/ |
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private array $blacklist = [ |
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Constants::SIG_RSA_SHA1, |
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Constants::SIG_HMAC_SHA1, |
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]; |
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/** |
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* A cache of signers indexed by algorithm ID. |
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* |
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* @var string[] |
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*/ |
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private static array $cache = []; |
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/** |
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* Whether the factory has been initialized or not. |
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* |
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* @var bool |
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*/ |
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private static bool $initialized = false; |
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/** |
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* Build a factory that creates signature algorithms. |
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* |
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* @param string[]|null $blacklist |
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*/ |
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public function __construct(array $blacklist = null) |
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{ |
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if ($blacklist !== null) { |
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$this->blacklist = $blacklist; |
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} |
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// initialize the cache for supported algorithms per known signer |
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if (!self::$initialized) { |
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foreach (self::$algorithms as $algorithm) { |
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self::updateCache($algorithm); |
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} |
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self::$initialized = true; |
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} |
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} |
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/** |
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* Get a new object implementing the given digital signature algorithm. |
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* |
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* @param string $algId The identifier of the algorithm desired. |
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* @param \SimpleSAML\XMLSecurity\Key\AbstractKey $key The key to use with the given algorithm. |
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* |
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* @return \SimpleSAML\XMLSecurity\Alg\SignatureAlgorithm An object implementing the given algorithm. |
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* |
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* @throws \SimpleSAML\XMLSecurity\Exception\InvalidArgumentException If an error occurs, e.g. the given algorithm |
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* is blacklisted, unknown or the given key is not suitable for it. |
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*/ |
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public function getAlgorithm(string $algId, AbstractKey $key): SignatureAlgorithm |
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{ |
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if (in_array($algId, $this->blacklist)) { |
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throw new InvalidArgumentException('Blacklisted signature algorithm'); |
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} |
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if (!array_key_exists($algId, self::$cache)) { |
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throw new InvalidArgumentException('Unknown algorithm identifier.'); |
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} |
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return new self::$cache[$algId]($key, $algId); |
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} |
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/** |
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* Register a signature algorithm for its use. |
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* |
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* @note Algorithms must extend \SimpleSAML\XMLSecurity\Alg\Signature\AbstractSigner. |
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* |
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* @param string $className |
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*/ |
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public static function registerAlgorithm(string $className): void |
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{ |
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Assert::subclassOf( |
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$className, |
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AbstractSigner::class, |
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'Cannot register algorithm "' . $className . '", must implement ' . "\SimpleSAML\XMLSecurity\Alg\SignatureInterface.", |
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InvalidArgumentException::class |
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); |
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self::$algorithms[] = $className; |
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self::updateCache($className); |
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} |
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/** |
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* Update the cache with a new signer implementation. |
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* |
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* @param string $signer |
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*/ |
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private static function updateCache(string $signer): void |
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{ |
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/** @var \SimpleSAML\XMLSecurity\Alg\Signature\AbstractSigner $signer */ |
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foreach ($signer::getSupportedAlgorithms() as $algId) { |
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self::$cache[$algId] = $signer; |
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} |
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} |
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} |
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