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tgseclib/phpseclib/Crypt/RSA/PKCS.php
Paragon Initiative Enterprises 0e8fa93676 Use paragonie/constant_time_encoding
2016-05-12 16:28:40 -04:00

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<?php
/**
* PKCS Formatted RSA Key Handler
*
* PHP version 5
*
* @category Crypt
* @package RSA
* @author Jim Wigginton <terrafrost@php.net>
* @copyright 2015 Jim Wigginton
* @license http://www.opensource.org/licenses/mit-license.html MIT License
* @link http://phpseclib.sourceforge.net
*/
namespace phpseclib\Crypt\RSA;
use ParagonIE\ConstantTime\Base64;
use ParagonIE\ConstantTime\Hex;
use phpseclib\Crypt\AES;
use phpseclib\Crypt\Base;
use phpseclib\Crypt\DES;
use phpseclib\Crypt\TripleDES;
use phpseclib\Math\BigInteger;
/**
* PKCS Formatted RSA Key Handler
*
* @package RSA
* @author Jim Wigginton <terrafrost@php.net>
* @access public
*/
abstract class PKCS
{
/**#@+
* @access private
* @see \phpseclib\Crypt\RSA::createKey()
*/
/**
* ASN1 Integer
*/
const ASN1_INTEGER = 2;
/**
* ASN1 Bit String
*/
const ASN1_BITSTRING = 3;
/**
* ASN1 Octet String
*/
const ASN1_OCTETSTRING = 4;
/**
* ASN1 Object Identifier
*/
const ASN1_OBJECT = 6;
/**
* ASN1 Sequence (with the constucted bit set)
*/
const ASN1_SEQUENCE = 48;
/**#@-*/
/**#@+
* @access private
*/
/**
* Auto-detect the format
*/
const MODE_ANY = 0;
/**
* Require base64-encoded PEM's be supplied
*/
const MODE_PEM = 1;
/**
* Require raw DER's be supplied
*/
const MODE_DER = 2;
/**#@-*/
/**
* Is the key a base-64 encoded PEM, DER or should it be auto-detected?
*
* @access private
* @param int
*/
static $format = self::MODE_ANY;
/**
* Returns the mode constant corresponding to the mode string
*
* @access public
* @param string $mode
* @return int
* @throws \UnexpectedValueException if the block cipher mode is unsupported
*/
static function getEncryptionMode($mode)
{
switch ($mode) {
case 'CBC':
return Base::MODE_CBC;
case 'ECB':
return Base::MODE_ECB;
case 'CFB':
return Base::MODE_CFB;
case 'OFB':
return Base::MODE_OFB;
case 'CTR':
return Base::MODE_CTR;
}
throw new \UnexpectedValueException('Unsupported block cipher mode of operation');
}
/**
* Returns a cipher object corresponding to a string
*
* @access public
* @param string $algo
* @return string
* @throws \UnexpectedValueException if the encryption algorithm is unsupported
*/
static function getEncryptionObject($algo)
{
$modes = '(CBC|ECB|CFB|OFB|CTR)';
switch (true) {
case preg_match("#^AES-(128|192|256)-$modes$#", $algo, $matches):
$cipher = new AES(self::getEncryptionMode($matches[2]));
$cipher->setKeyLength($matches[1]);
return $cipher;
case preg_match("#^DES-EDE3-$modes$#", $algo, $matches):
return new TripleDES(self::getEncryptionMode($matches[1]));
case preg_match("#^DES-$modes$#", $algo, $matches):
return new DES(self::getEncryptionMode($matches[1]));
default:
throw new \UnexpectedValueException('Unsupported encryption algorithmn');
}
}
/**
* Generate a symmetric key for PKCS#1 keys
*
* @access public
* @param string $password
* @param string $iv
* @param int $length
* @return string
*/
static function generateSymmetricKey($password, $iv, $length)
{
$symkey = '';
$iv = substr($iv, 0, 8);
while (strlen($symkey) < $length) {
$symkey.= Hex::decode(md5($symkey . $password . $iv));
}
return substr($symkey, 0, $length);
}
/**
* Break a public or private key down into its constituent components
*
* @access public
* @param string $key
* @param string $password optional
* @return array
*/
static function load($key, $password = '')
{
if (!is_string($key)) {
return false;
}
$components = array('isPublicKey' => strpos($key, 'PUBLIC') !== false);
/* Although PKCS#1 proposes a format that public and private keys can use, encrypting them is
"outside the scope" of PKCS#1. PKCS#1 then refers you to PKCS#12 and PKCS#15 if you're wanting to
protect private keys, however, that's not what OpenSSL* does. OpenSSL protects private keys by adding
two new "fields" to the key - DEK-Info and Proc-Type. These fields are discussed here:
http://tools.ietf.org/html/rfc1421#section-4.6.1.1
http://tools.ietf.org/html/rfc1421#section-4.6.1.3
DES-EDE3-CBC as an algorithm, however, is not discussed anywhere, near as I can tell.
DES-CBC and DES-EDE are discussed in RFC1423, however, DES-EDE3-CBC isn't, nor is its key derivation
function. As is, the definitive authority on this encoding scheme isn't the IETF but rather OpenSSL's
own implementation. ie. the implementation *is* the standard and any bugs that may exist in that
implementation are part of the standard, as well.
* OpenSSL is the de facto standard. It's utilized by OpenSSH and other projects */
if (preg_match('#DEK-Info: (.+),(.+)#', $key, $matches)) {
$iv = Hex::decode(trim($matches[2]));
// remove the Proc-Type / DEK-Info sections as they're no longer needed
$key = preg_replace('#^(?:Proc-Type|DEK-Info): .*#m', '', $key);
$ciphertext = self::_extractBER($key);
if ($ciphertext === false) {
$ciphertext = $key;
}
$crypto = self::getEncryptionObject($matches[1]);
$crypto->setKey(self::generateSymmetricKey($password, $iv, $crypto->getKeyLength() >> 3));
$crypto->setIV($iv);
$key = $crypto->decrypt($ciphertext);
if ($key === false) {
return false;
}
} else {
if (self::$format != self::MODE_DER) {
$decoded = self::_extractBER($key);
if ($decoded !== false) {
$key = $decoded;
} elseif (self::$format == self::MODE_PEM) {
return false;
}
}
}
if (ord(self::_string_shift($key)) != self::ASN1_SEQUENCE) {
return false;
}
if (self::_decodeLength($key) != strlen($key)) {
return false;
}
$tag = ord(self::_string_shift($key));
/* intended for keys for which OpenSSL's asn1parse returns the following:
0:d=0 hl=4 l= 631 cons: SEQUENCE
4:d=1 hl=2 l= 1 prim: INTEGER :00
7:d=1 hl=2 l= 13 cons: SEQUENCE
9:d=2 hl=2 l= 9 prim: OBJECT :rsaEncryption
20:d=2 hl=2 l= 0 prim: NULL
22:d=1 hl=4 l= 609 prim: OCTET STRING
ie. PKCS8 keys */
if ($tag == self::ASN1_INTEGER && substr($key, 0, 3) == "\x01\x00\x30") {
self::_string_shift($key, 3);
$tag = self::ASN1_SEQUENCE;
}
if ($tag == self::ASN1_SEQUENCE) {
$temp = self::_string_shift($key, self::_decodeLength($key));
if (ord(self::_string_shift($temp)) != self::ASN1_OBJECT) {
return false;
}
$length = self::_decodeLength($temp);
switch (self::_string_shift($temp, $length)) {
case "\x2a\x86\x48\x86\xf7\x0d\x01\x01\x01": // rsaEncryption
break;
case "\x2a\x86\x48\x86\xf7\x0d\x01\x05\x03": // pbeWithMD5AndDES-CBC
/*
PBEParameter ::= SEQUENCE {
salt OCTET STRING (SIZE(8)),
iterationCount INTEGER }
*/
if (ord(self::_string_shift($temp)) != self::ASN1_SEQUENCE) {
return false;
}
if (self::_decodeLength($temp) != strlen($temp)) {
return false;
}
self::_string_shift($temp); // assume it's an octet string
$salt = self::_string_shift($temp, self::_decodeLength($temp));
if (ord(self::_string_shift($temp)) != self::ASN1_INTEGER) {
return false;
}
self::_decodeLength($temp);
list(, $iterationCount) = unpack('N', str_pad($temp, 4, chr(0), STR_PAD_LEFT));
self::_string_shift($key); // assume it's an octet string
$length = self::_decodeLength($key);
if (strlen($key) != $length) {
return false;
}
$crypto = new DES(DES::MODE_CBC);
$crypto->setPassword($password, 'pbkdf1', 'md5', $salt, $iterationCount);
$key = $crypto->decrypt($key);
if ($key === false) {
return false;
}
return self::load($key);
default:
return false;
}
/* intended for keys for which OpenSSL's asn1parse returns the following:
0:d=0 hl=4 l= 290 cons: SEQUENCE
4:d=1 hl=2 l= 13 cons: SEQUENCE
6:d=2 hl=2 l= 9 prim: OBJECT :rsaEncryption
17:d=2 hl=2 l= 0 prim: NULL
19:d=1 hl=4 l= 271 prim: BIT STRING */
$tag = ord(self::_string_shift($key)); // skip over the BIT STRING / OCTET STRING tag
self::_decodeLength($key); // skip over the BIT STRING / OCTET STRING length
// "The initial octet shall encode, as an unsigned binary integer wtih bit 1 as the least significant bit, the number of
// unused bits in the final subsequent octet. The number shall be in the range zero to seven."
// -- http://www.itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf (section 8.6.2.2)
if ($tag == self::ASN1_BITSTRING) {
self::_string_shift($key);
}
if (ord(self::_string_shift($key)) != self::ASN1_SEQUENCE) {
return false;
}
if (self::_decodeLength($key) != strlen($key)) {
return false;
}
$tag = ord(self::_string_shift($key));
}
if ($tag != self::ASN1_INTEGER) {
return false;
}
$length = self::_decodeLength($key);
$temp = self::_string_shift($key, $length);
if (strlen($temp) != 1 || ord($temp) > 2) {
$components['modulus'] = new BigInteger($temp, 256);
self::_string_shift($key); // skip over self::ASN1_INTEGER
$length = self::_decodeLength($key);
$components[$components['isPublicKey'] ? 'publicExponent' : 'privateExponent'] = new BigInteger(self::_string_shift($key, $length), 256);
return $components;
}
if (ord(self::_string_shift($key)) != self::ASN1_INTEGER) {
return false;
}
$length = self::_decodeLength($key);
$components['modulus'] = new BigInteger(self::_string_shift($key, $length), 256);
self::_string_shift($key);
$length = self::_decodeLength($key);
$components['publicExponent'] = new BigInteger(self::_string_shift($key, $length), 256);
self::_string_shift($key);
$length = self::_decodeLength($key);
$components['privateExponent'] = new BigInteger(self::_string_shift($key, $length), 256);
self::_string_shift($key);
$length = self::_decodeLength($key);
$components['primes'] = array(1 => new BigInteger(self::_string_shift($key, $length), 256));
self::_string_shift($key);
$length = self::_decodeLength($key);
$components['primes'][] = new BigInteger(self::_string_shift($key, $length), 256);
self::_string_shift($key);
$length = self::_decodeLength($key);
$components['exponents'] = array(1 => new BigInteger(self::_string_shift($key, $length), 256));
self::_string_shift($key);
$length = self::_decodeLength($key);
$components['exponents'][] = new BigInteger(self::_string_shift($key, $length), 256);
self::_string_shift($key);
$length = self::_decodeLength($key);
$components['coefficients'] = array(2 => new BigInteger(self::_string_shift($key, $length), 256));
if (!empty($key)) {
if (ord(self::_string_shift($key)) != self::ASN1_SEQUENCE) {
return false;
}
self::_decodeLength($key);
while (!empty($key)) {
if (ord(self::_string_shift($key)) != self::ASN1_SEQUENCE) {
return false;
}
self::_decodeLength($key);
$key = substr($key, 1);
$length = self::_decodeLength($key);
$components['primes'][] = new BigInteger(self::_string_shift($key, $length), 256);
self::_string_shift($key);
$length = self::_decodeLength($key);
$components['exponents'][] = new BigInteger(self::_string_shift($key, $length), 256);
self::_string_shift($key);
$length = self::_decodeLength($key);
$components['coefficients'][] = new BigInteger(self::_string_shift($key, $length), 256);
}
}
return $components;
}
/**
* Require base64-encoded PEM's be supplied
*
* @see self::load()
* @access public
*/
static function requirePEM()
{
self::$format = self::MODE_PEM;
}
/**
* Require raw DER's be supplied
*
* @see self::load()
* @access public
*/
static function requireDER()
{
self::$format = self::MODE_DER;
}
/**
* Accept any format and auto detect the format
*
* This is the default setting
*
* @see self::load()
* @access public
*/
static function requireAny()
{
self::$format = self::MODE_ANY;
}
/**
* DER-decode the length
*
* DER supports lengths up to (2**8)**127, however, we'll only support lengths up to (2**8)**4. See
* {@link http://itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf#p=13 X.690 paragraph 8.1.3} for more information.
*
* @access private
* @param string $string
* @return int
*/
static function _decodeLength(&$string)
{
$length = ord(self::_string_shift($string));
if ($length & 0x80) { // definite length, long form
$length&= 0x7F;
$temp = self::_string_shift($string, $length);
list(, $length) = unpack('N', substr(str_pad($temp, 4, chr(0), STR_PAD_LEFT), -4));
}
return $length;
}
/**
* DER-encode the length
*
* DER supports lengths up to (2**8)**127, however, we'll only support lengths up to (2**8)**4. See
* {@link http://itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf#p=13 X.690 paragraph 8.1.3} for more information.
*
* @access private
* @param int $length
* @return string
*/
static function _encodeLength($length)
{
if ($length <= 0x7F) {
return chr($length);
}
$temp = ltrim(pack('N', $length), chr(0));
return pack('Ca*', 0x80 | strlen($temp), $temp);
}
/**
* String Shift
*
* Inspired by array_shift
*
* @param string $string
* @param int $index
* @return string
* @access private
*/
static function _string_shift(&$string, $index = 1)
{
$substr = substr($string, 0, $index);
$string = substr($string, $index);
return $substr;
}
/**
* Extract raw BER from Base64 encoding
*
* @access private
* @param string $str
* @return string
*/
static function _extractBER($str)
{
/* X.509 certs are assumed to be base64 encoded but sometimes they'll have additional things in them
* above and beyond the ceritificate.
* ie. some may have the following preceding the -----BEGIN CERTIFICATE----- line:
*
* Bag Attributes
* localKeyID: 01 00 00 00
* subject=/O=organization/OU=org unit/CN=common name
* issuer=/O=organization/CN=common name
*/
$temp = preg_replace('#.*?^-+[^-]+-+[\r\n ]*$#ms', '', $str, 1);
// remove the -----BEGIN CERTIFICATE----- and -----END CERTIFICATE----- stuff
$temp = preg_replace('#-+[^-]+-+#', '', $temp);
// remove new lines
$temp = str_replace(array("\r", "\n", ' '), '', $temp);
$temp = preg_match('#^[a-zA-Z\d/+]*={0,2}$#', $temp) ? Base64::decode($temp) : false;
return $temp != false ? $temp : $str;
}
}
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