* @since 1.27
*/
final class Session implements \Countable, \Iterator, \ArrayAccess {
+ /** @var null|string[] Encryption algorithm to use */
+ private static $encryptionAlgorithm = null;
+
/** @var SessionBackend Session backend */
private $backend;
/**
* Make this session not be persisted across requests
+ *
+ * This will remove persistence information (e.g. delete cookies)
+ * from the associated WebRequest(s), and delete session data in the
+ * backend. The session data will still be available via get() until
+ * the end of the request.
*/
public function unpersist() {
$this->backend->unpersist();
$this->remove( 'wsTokenSecrets' );
}
+ /**
+ * Fetch the secret keys for self::setSecret() and self::getSecret().
+ * @return string[] Encryption key, HMAC key
+ */
+ private function getSecretKeys() {
+ global $wgSessionSecret, $wgSecretKey, $wgSessionPbkdf2Iterations;
+
+ $wikiSecret = $wgSessionSecret ?: $wgSecretKey;
+ $userSecret = $this->get( 'wsSessionSecret', null );
+ if ( $userSecret === null ) {
+ $userSecret = \MWCryptRand::generateHex( 32 );
+ $this->set( 'wsSessionSecret', $userSecret );
+ }
+ $iterations = $this->get( 'wsSessionPbkdf2Iterations', null );
+ if ( $iterations === null ) {
+ $iterations = $wgSessionPbkdf2Iterations;
+ $this->set( 'wsSessionPbkdf2Iterations', $iterations );
+ }
+
+ $keymats = hash_pbkdf2( 'sha256', $wikiSecret, $userSecret, $iterations, 64, true );
+ return [
+ substr( $keymats, 0, 32 ),
+ substr( $keymats, 32, 32 ),
+ ];
+ }
+
+ /**
+ * Decide what type of encryption to use, based on system capabilities.
+ * @return array
+ */
+ private static function getEncryptionAlgorithm() {
+ global $wgSessionInsecureSecrets;
+
+ if ( self::$encryptionAlgorithm === null ) {
+ if ( function_exists( 'openssl_encrypt' ) ) {
+ $methods = openssl_get_cipher_methods();
+ if ( in_array( 'aes-256-ctr', $methods, true ) ) {
+ self::$encryptionAlgorithm = [ 'openssl', 'aes-256-ctr' ];
+ return self::$encryptionAlgorithm;
+ }
+ if ( in_array( 'aes-256-cbc', $methods, true ) ) {
+ self::$encryptionAlgorithm = [ 'openssl', 'aes-256-cbc' ];
+ return self::$encryptionAlgorithm;
+ }
+ }
+
+ if ( function_exists( 'mcrypt_encrypt' )
+ && in_array( 'rijndael-128', mcrypt_list_algorithms(), true )
+ ) {
+ $modes = mcrypt_list_modes();
+ if ( in_array( 'ctr', $modes, true ) ) {
+ self::$encryptionAlgorithm = [ 'mcrypt', 'rijndael-128', 'ctr' ];
+ return self::$encryptionAlgorithm;
+ }
+ if ( in_array( 'cbc', $modes, true ) ) {
+ self::$encryptionAlgorithm = [ 'mcrypt', 'rijndael-128', 'cbc' ];
+ return self::$encryptionAlgorithm;
+ }
+ }
+
+ if ( $wgSessionInsecureSecrets ) {
+ // @todo: import a pure-PHP library for AES instead of this
+ self::$encryptionAlgorithm = [ 'insecure' ];
+ return self::$encryptionAlgorithm;
+ }
+
+ throw new \BadMethodCallException(
+ 'Encryption is not available. You really should install the PHP OpenSSL extension, ' .
+ 'or failing that the mcrypt extension. But if you really can\'t and you\'re willing ' .
+ 'to accept insecure storage of sensitive session data, set ' .
+ '$wgSessionInsecureSecrets = true in LocalSettings.php to make this exception go away.'
+ );
+ }
+
+ return self::$encryptionAlgorithm;
+ }
+
+ /**
+ * Set a value in the session, encrypted
+ *
+ * This relies on the secrecy of $wgSecretKey (by default), or $wgSessionSecret.
+ *
+ * @param string|int $key
+ * @param mixed $value
+ */
+ public function setSecret( $key, $value ) {
+ list( $encKey, $hmacKey ) = $this->getSecretKeys();
+ $serialized = serialize( $value );
+
+ // The code for encryption (with OpenSSL) and sealing is taken from
+ // Chris Steipp's OATHAuthUtils class in Extension::OATHAuth.
+
+ // Encrypt
+ // @todo: import a pure-PHP library for AES instead of doing $wgSessionInsecureSecrets
+ $iv = \MWCryptRand::generate( 16, true );
+ $algorithm = self::getEncryptionAlgorithm();
+ switch ( $algorithm[0] ) {
+ case 'openssl':
+ $ciphertext = openssl_encrypt( $serialized, $algorithm[1], $encKey, OPENSSL_RAW_DATA, $iv );
+ if ( $ciphertext === false ) {
+ throw new \UnexpectedValueException( 'Encryption failed: ' . openssl_error_string() );
+ }
+ break;
+ case 'mcrypt':
+ // PKCS7 padding
+ $blocksize = mcrypt_get_block_size( $algorithm[1], $algorithm[2] );
+ $pad = $blocksize - ( strlen( $serialized ) % $blocksize );
+ $serialized .= str_repeat( chr( $pad ), $pad );
+
+ $ciphertext = mcrypt_encrypt( $algorithm[1], $encKey, $serialized, $algorithm[2], $iv );
+ if ( $ciphertext === false ) {
+ throw new \UnexpectedValueException( 'Encryption failed' );
+ }
+ break;
+ case 'insecure':
+ $ex = new \Exception( 'No encryption is available, storing data as plain text' );
+ $this->logger->warning( $ex->getMessage(), [ 'exception' => $ex ] );
+ $ciphertext = $serialized;
+ break;
+ default:
+ throw new \LogicException( 'invalid algorithm' );
+ }
+
+ // Seal
+ $sealed = base64_encode( $iv ) . '.' . base64_encode( $ciphertext );
+ $hmac = hash_hmac( 'sha256', $sealed, $hmacKey, true );
+ $encrypted = base64_encode( $hmac ) . '.' . $sealed;
+
+ // Store
+ $this->set( $key, $encrypted );
+ }
+
+ /**
+ * Fetch a value from the session that was set with self::setSecret()
+ * @param string|int $key
+ * @param mixed $default Returned if $this->exists( $key ) would be false or decryption fails
+ * @return mixed
+ */
+ public function getSecret( $key, $default = null ) {
+ // Fetch
+ $encrypted = $this->get( $key, null );
+ if ( $encrypted === null ) {
+ return $default;
+ }
+
+ // The code for unsealing, checking, and decrypting (with OpenSSL) is
+ // taken from Chris Steipp's OATHAuthUtils class in
+ // Extension::OATHAuth.
+
+ // Unseal and check
+ $pieces = explode( '.', $encrypted );
+ if ( count( $pieces ) !== 3 ) {
+ $ex = new \Exception( 'Invalid sealed-secret format' );
+ $this->logger->warning( $ex->getMessage(), [ 'exception' => $ex ] );
+ return $default;
+ }
+ list( $hmac, $iv, $ciphertext ) = $pieces;
+ list( $encKey, $hmacKey ) = $this->getSecretKeys();
+ $integCalc = hash_hmac( 'sha256', $iv . '.' . $ciphertext, $hmacKey, true );
+ if ( !hash_equals( $integCalc, base64_decode( $hmac ) ) ) {
+ $ex = new \Exception( 'Sealed secret has been tampered with, aborting.' );
+ $this->logger->warning( $ex->getMessage(), [ 'exception' => $ex ] );
+ return $default;
+ }
+
+ // Decrypt
+ $algorithm = self::getEncryptionAlgorithm();
+ switch ( $algorithm[0] ) {
+ case 'openssl':
+ $serialized = openssl_decrypt( base64_decode( $ciphertext ), $algorithm[1], $encKey,
+ OPENSSL_RAW_DATA, base64_decode( $iv ) );
+ if ( $serialized === false ) {
+ $ex = new \Exception( 'Decyption failed: ' . openssl_error_string() );
+ $this->logger->debug( $ex->getMessage(), [ 'exception' => $ex ] );
+ return $default;
+ }
+ break;
+ case 'mcrypt':
+ $serialized = mcrypt_decrypt( $algorithm[1], $encKey, base64_decode( $ciphertext ),
+ $algorithm[2], base64_decode( $iv ) );
+ if ( $serialized === false ) {
+ $ex = new \Exception( 'Decyption failed' );
+ $this->logger->debug( $ex->getMessage(), [ 'exception' => $ex ] );
+ return $default;
+ }
+
+ // Remove PKCS7 padding
+ $pad = ord( substr( $serialized, -1 ) );
+ $serialized = substr( $serialized, 0, -$pad );
+ break;
+ case 'insecure':
+ $ex = new \Exception(
+ 'No encryption is available, retrieving data that was stored as plain text'
+ );
+ $this->logger->warning( $ex->getMessage(), [ 'exception' => $ex ] );
+ $serialized = base64_decode( $ciphertext );
+ break;
+ default:
+ throw new \LogicException( 'invalid algorithm' );
+ }
+
+ $value = unserialize( $serialized );
+ if ( $value === false && $serialized !== serialize( false ) ) {
+ $value = $default;
+ }
+ return $value;
+ }
+
/**
* Delay automatic saving while multiple updates are being made
*
* Calls to save() or clear() will not be delayed.
*
- * @return \ScopedCallback When this goes out of scope, a save will be triggered
+ * @return \Wikimedia\ScopedCallback When this goes out of scope, a save will be triggered
*/
public function delaySave() {
return $this->backend->delaySave();
/**
* Save the session
+ *
+ * This will update the backend data and might re-persist the session
+ * if needed.
*/
public function save() {
$this->backend->save();
dépôts / lhc / web / wiklou.git / blobdiff