/**
* Parses ASN.1 string [$str] starting form position [$pos].
* Returns tag and string value of parsed object.
*
* @param string $str
* @param int $pos
* @param Crypt_RSA_ErrorHandler $err_handler
*
* @return mixed Array('tag' => ..., 'str' => ...) on success, false on error
* @access private
*/
function _ASN1Parse($str, &$pos, &$err_handler)
{
$max_pos = strlen($str);
if ($max_pos < 2) {
$err_handler->pushError("ASN.1 string too short");
return false;
}
// get ASN.1 tag value
$tag = ord($str[$pos++]) & 0x1f;
if ($tag == 0x1f) {
$tag = 0;
do {
$n = ord($str[$pos++]);
$tag <<= 7;
$tag |= $n & 0x7f;
} while ($n & 0x80 && $pos < $max_pos);
}
if ($pos >= $max_pos) {
$err_handler->pushError("ASN.1 string too short");
return false;
}
// get ASN.1 object length
$len = ord($str[$pos++]);
if ($len & 0x80) {
$n = $len & 0x1f;
$len = 0;
while ($n-- && $pos < $max_pos) {
$len <<= 8;
$len |= ord($in[$pos++]);
}
}
if ($pos >= $max_pos || $len > $max_pos - $pos) {
$err_handler->pushError("ASN.1 string too short");
return false;
}
// get string value of ASN.1 object
$str = substr($str, $pos, $len);
return array('tag' => $tag, 'str' => $str);
}
/**
* Retrieves RSA keypair from PEM-encoded string, containing RSA private key.
* Example of such string:
* -----BEGIN RSA PRIVATE KEY-----
* MCsCAQACBHtvbSECAwEAAQIEeYrk3QIDAOF3AgMAjCcCAmdnAgJMawIDALEk
* -----END RSA PRIVATE KEY-----
*
* Wrapper: Name of math wrapper, which will be used to
* perform different operations with big integers.
* See contents of Crypt/RSA/Math folder for examples of wrappers.
* Read docs/Crypt_RSA/docs/math_wrappers.txt for details.
*
* @param string $str PEM-encoded string
* @param string $wrapper_name Wrapper name
* @param string $error_handler name of error handler function
*
* @return Crypt_RSA_KeyPair object on success, PEAR_Error object on error
* @access public
* @static
*/
function &fromPEMString($str, $wrapper_name = 'default', $error_handler = '')
{
if (isset($this)) {
if ($wrapper_name == 'default') {
$wrapper_name = $this->_math_obj->getWrapperName();
}
if ($error_handler == '') {
$error_handler = $this->_error_handler;
}
}
$err_handler = new Crypt_RSA_ErrorHandler();
$err_handler->setErrorHandler($error_handler);
// search for base64-encoded private key
if (!preg_match('/-----BEGIN RSA PRIVATE KEY-----([^-]+)-----END RSA PRIVATE KEY-----/', $str, $matches)) {
$err_handler->pushError("can't find RSA private key in the string [{$str}]");
return $err_handler->getLastError();
}
// parse private key. It is ASN.1-encoded
$str = base64_decode($matches[1]);
$pos = 0;
$tmp = Crypt_RSA_KeyPair::_ASN1Parse($str, $pos, $err_handler);
if ($err_handler->isError()) {
return $err_handler->getLastError();
}
if ($tmp['tag'] != 0x10) {
$errstr = sprintf("wrong ASN tag value: 0x%02x. Expected 0x10 (SEQUENCE)", $tmp['tag']);
$err_handler->pushError($errstr);
return $err_handler->getLastError();
}
// parse ASN.1 SEQUENCE for RSA private key
$attr_names = Crypt_RSA_KeyPair::_get_attr_names();
$n = sizeof($attr_names);
$rsa_attrs = array();
for ($i = 0; $i < $n; $i++) {
$tmp = Crypt_RSA_KeyPair::_ASN1ParseInt($str, $pos, $err_handler);
if ($err_handler->isError()) {
return $err_handler->getLastError();
}
$attr = $attr_names[$i];
$rsa_attrs[$attr] = $tmp;
}
// create Crypt_RSA_KeyPair object.
$keypair = new Crypt_RSA_KeyPair($rsa_attrs, $wrapper_name, $error_handler);
if ($keypair->isError()) {
return $keypair->getLastError();
}
return $keypair;
}
/**
* Loads RSA math wrapper with name $wrapper_name.
* Implemented wrappers can be found at Crypt/RSA/Math folder.
* Read docs/Crypt_RSA/docs/math_wrappers.txt for details
*
* This is a static function:
* // load BigInt wrapper
* $big_int_wrapper = &Crypt_RSA_MathLoader::loadWrapper('BigInt');
*
* // load BCMath wrapper
* $bcmath_wrapper = &Crypt_RSA_MathLoader::loadWrapper('BCMath');
*
* @param string $wrapper_name Name of wrapper
*
* @return object
* Reference to object of wrapper with name $wrapper_name on success
* or PEAR_Error object on error
*
* @access public
*/
function loadWrapper($wrapper_name = 'default')
{
static $math_objects = array();
// ordered by performance. GMP is the fastest math library, BCMath - the slowest.
static $math_wrappers = array('GMP', 'BigInt', 'BCMath');
if (isset($math_objects[$wrapper_name])) {
/*
wrapper with name $wrapper_name is already loaded and created.
Return reference to existing copy of wrapper
*/
return $math_objects[$wrapper_name];
}
$err_handler = new Crypt_RSA_ErrorHandler();
if ($wrapper_name === 'default') {
// try to load the most suitable wrapper
$n = sizeof($math_wrappers);
for ($i = 0; $i < $n; $i++) {
$obj = Crypt_RSA_MathLoader::loadWrapper($math_wrappers[$i]);
if (!$err_handler->isError($obj)) {
// wrapper for $math_wrappers[$i] successfully loaded
// register it as default wrapper and return reference to it
return $math_objects['default'] = $obj;
}
}
// can't load any wrapper
$err_handler->pushError("can't load any wrapper for existing math libraries", CRYPT_RSA_ERROR_NO_WRAPPERS);
return $err_handler->getLastError();
}
$class_name = 'Crypt_RSA_Math_' . $wrapper_name;
$class_filename = dirname(__FILE__) . '/Math/' . $wrapper_name . '.php';
if (!is_file($class_filename)) {
$err_handler->pushError("can't find file [{$class_filename}] for RSA math wrapper [{$wrapper_name}]", CRYPT_RSA_ERROR_NO_FILE);
return $err_handler->getLastError();
}
include_once $class_filename;
if (!class_exists($class_name)) {
$err_handler->pushError("can't find class [{$class_name}] in file [{$class_filename}]", CRYPT_RSA_ERROR_NO_CLASS);
return $err_handler->getLastError();
}
// create and return wrapper object on success or PEAR_Error object on error
$obj = new $class_name();
if ($obj->errstr) {
// cannot load required extension for math wrapper
$err_handler->pushError($obj->errstr, CRYPT_RSA_ERROR_NO_EXT);
return $err_handler->getLastError();
}
return $math_objects[$wrapper_name] = $obj;
}