* @copyright 2009 Jim Wigginton * @license http://www.opensource.org/licenses/mit-license.html MIT License * @link http://phpseclib.sourceforge.net * @internal See http://api.libssh.org/rfc/PROTOCOL.agent */ namespace phpseclib\System\SSH\Agent; use phpseclib\Crypt\RSA; use phpseclib\Exception\UnsupportedAlgorithmException; use phpseclib\System\SSH\Agent; use phpseclib\Common\Functions\Strings; /** * Pure-PHP ssh-agent client identity object * * Instantiation should only be performed by \phpseclib\System\SSH\Agent class. * This could be thought of as implementing an interface that phpseclib\Crypt\RSA * implements. ie. maybe a Net_SSH_Auth_PublicKey interface or something. * The methods in this interface would be getPublicKey and sign since those are the * methods phpseclib looks for to perform public key authentication. * * @package SSH\Agent * @author Jim Wigginton * @access internal */ class Identity { /**@+ * Signature Flags * * See https://tools.ietf.org/html/draft-miller-ssh-agent-00#section-5.3 * * @access private */ const SSH_AGENT_RSA2_256 = 2; const SSH_AGENT_RSA2_512 = 4; /**#@-*/ /** * Key Object * * @var \phpseclib\Crypt\RSA * @access private * @see self::getPublicKey() */ private $key; /** * Key Blob * * @var string * @access private * @see self::sign() */ private $key_blob; /** * Socket Resource * * @var resource * @access private * @see self::sign() */ private $fsock; /** * Signature flags * * @var int * @access private * @see self::sign() * @see self::setHash() */ var $flags = 0; /** * Default Constructor. * * @param resource $fsock * @return \phpseclib\System\SSH\Agent\Identity * @access private */ public function __construct($fsock) { $this->fsock = $fsock; } /** * Set Public Key * * Called by \phpseclib\System\SSH\Agent::requestIdentities() * * @param \phpseclib\Crypt\RSA $key * @access private */ public function setPublicKey($key) { $this->key = $key; $this->key->setPublicKey(); } /** * Set Public Key * * Called by \phpseclib\System\SSH\Agent::requestIdentities(). The key blob could be extracted from $this->key * but this saves a small amount of computation. * * @param string $key_blob * @access private */ public function setPublicKeyBlob($key_blob) { $this->key_blob = $key_blob; } /** * Get Public Key * * Wrapper for $this->key->getPublicKey() * * @param string $type optional * @return mixed * @access public */ public function getPublicKey($type = 'PKCS8') { return $this->key->getPublicKey($type); } /** * Sets the hash * * ssh-agent only supports signatures with sha1 hashes but to maintain BC with RSA.php this function exists * * @param string $hash optional * @access public */ public function setHash($hash) { $this->flags = 0; switch ($hash) { case 'sha1': break; case 'sha256': $this->flags = self::SSH_AGENT_RSA2_256; break; case 'sha512': $this->flags = self::SSH_AGENT_RSA2_512; break; default: throw new UnsupportedAlgorithmException('The only supported hashes for RSA are sha1, sha256 and sha512'); } } /** * Create a signature * * See "2.6.2 Protocol 2 private key signature request" * * @param string $message * @param int $padding optional * @return string * @throws \RuntimeException on connection errors * @throws \phpseclib\Exception\UnsupportedAlgorithmException if the algorithm is unsupported * @access public */ public function sign($message, $padding = RSA::PADDING_PKCS1) { if ($padding != RSA::PADDING_PKCS1 && $padding != RSA::PADDING_RELAXED_PKCS1) { throw new UnsupportedAlgorithmException('ssh-agent can only create PKCS1 signatures'); } // the last parameter (currently 0) is for flags and ssh-agent only defines one flag (for ssh-dss): SSH_AGENT_OLD_SIGNATURE $packet = pack('CNa*Na*N', Agent::SSH_AGENTC_SIGN_REQUEST, strlen($this->key_blob), $this->key_blob, strlen($message), $message, $this->flags); $packet = pack('Na*', strlen($packet), $packet); if (strlen($packet) != fputs($this->fsock, $packet)) { throw new \RuntimeException('Connection closed during signing'); } $length = current(unpack('N', fread($this->fsock, 4))); $type = ord(fread($this->fsock, 1)); if ($type != Agent::SSH_AGENT_SIGN_RESPONSE) { throw new \RuntimeException('Unable to retrieve signature'); } $signature_blob = fread($this->fsock, $length - 1); $length = current(unpack('N', Strings::shift($signature_blob, 4))); if ($length != strlen($signature_blob)) { throw new \RuntimeException('Malformed signature blob'); } $length = current(unpack('N', Strings::shift($signature_blob, 4))); if ($length > strlen($signature_blob) + 4) { throw new \RuntimeException('Malformed signature blob'); } $type = Strings::shift($signature_blob, $length); Strings::shift($signature_blob, 4); return $signature_blob; } }