* @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; /** * 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 { /** * Key Object * * @var \phpseclib\Crypt\RSA * @access private * @see self::getPublicKey() */ var $key; /** * Key Blob * * @var string * @access private * @see self::sign() */ var $key_blob; /** * Socket Resource * * @var resource * @access private * @see self::sign() */ var $fsock; /** * Default Constructor. * * @param resource $fsock * @return \phpseclib\System\SSH\Agent\Identity * @access private */ function __construct($fsock) { $this->fsock = $fsock; } /** * Set Public Key * * Called by \phpseclib\System\SSH\Agent::requestIdentities() * * @param \phpseclib\Crypt\RSA $key * @access private */ function setPublicKey($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 $key_blob * @access private */ function setPublicKeyBlob($key_blob) { $this->key_blob = $key_blob; } /** * Get Public Key * * Wrapper for $this->key->getPublicKey() * * @param int $type optional * @return mixed * @access public */ function getPublicKey($type = 'PKCS8') { return $this->key->getPublicKey($type); } /** * Create a signature * * See "2.6.2 Protocol 2 private key signature request" * * @param string $message * @param int $padding optional * @return string * @throws \RuntimeException on connection errors * @throws \phpseclib\Exception\UnsupportedAlgorithmException if the algorithm is unsupported * @access public */ function sign($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, 0); $packet = pack('Na*', strlen($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 retreive signature'); } $signature_blob = fread($this->fsock, $length - 1); // the only other signature format defined - ssh-dss - is the same length as ssh-rsa // the + 12 is for the other various SSH added length fields return substr($signature_blob, strlen('ssh-rsa') + 12); } }