/**
* Generates a random BigInteger
*
* Byte length is equal to $length. Uses crypt_random if it's loaded and mt_rand if it's not.
*
* @param Integer $length
* @return Math_BigInteger
* @access private
*/
function _random_number_helper($size)
{
if (function_exists('crypt_random_string')) {
$random = Crypt_Random::crypt_random_string($size);
} else {
$random = '';
if ($size & 1) {
$random .= chr(mt_rand(0, 255));
}
$blocks = $size >> 1;
for ($i = 0; $i < $blocks; ++$i) {
// mt_rand(-2147483648, 0x7FFFFFFF) always produces -2147483648 on some systems
$random .= pack('n', mt_rand(0, 0xffff));
}
}
return new Math_BigInteger($random, 256);
}
/**
* RSA Encrypt
*
* Returns mod(pow($m, $e), $n), where $n should be the product of two (large) primes $p and $q and where $e
* should be a number with the property that gcd($e, ($p - 1) * ($q - 1)) == 1. Could just make anything that
* calls this call modexp, instead, but I think this makes things clearer, maybe...
*
* @see Net_SSH1::Net_SSH1()
* @param Math_BigInteger $m
* @param Array $key
* @return Math_BigInteger
* @access private
*/
function _rsa_crypt($m, $key)
{
/*
if (!class_exists('Crypt_RSA')) {
include_once 'Crypt/RSA.php';
}
$rsa = new Crypt_RSA();
$rsa->loadKey($key, CRYPT_RSA_PUBLIC_FORMAT_RAW);
$rsa->setEncryptionMode(CRYPT_RSA_ENCRYPTION_PKCS1);
return $rsa->encrypt($m);
*/
// To quote from protocol-1.5.txt:
// The most significant byte (which is only partial as the value must be
// less than the public modulus, which is never a power of two) is zero.
//
// The next byte contains the value 2 (which stands for public-key
// encrypted data in the PKCS standard [PKCS#1]). Then, there are non-
// zero random bytes to fill any unused space, a zero byte, and the data
// to be encrypted in the least significant bytes, the last byte of the
// data in the least significant byte.
// Presumably the part of PKCS#1 they're refering to is "Section 7.2.1 Encryption Operation",
// under "7.2 RSAES-PKCS1-v1.5" and "7 Encryption schemes" of the following URL:
// ftp://ftp.rsasecurity.com/pub/pkcs/pkcs-1/pkcs-1v2-1.pdf
$modulus = $key[1]->toBytes();
$length = strlen($modulus) - strlen($m) - 3;
$random = '';
while (strlen($random) != $length) {
$block = Crypt_Random::crypt_random_string($length - strlen($random));
$block = str_replace("", '', $block);
$random .= $block;
}
$temp = chr(0) . chr(2) . $random . chr(0) . $m;
$m = new Math_BigInteger($temp, 256);
$m = $m->modPow($key[0], $key[1]);
return $m->toBytes();
}
/**
* Sends Binary Packets
*
* See '6. Binary Packet Protocol' of rfc4253 for more info.
*
* @param String $data
* @param optional String $logged
* @see Net_SSH2::_get_binary_packet()
* @return Boolean
* @access private
*/
function _send_binary_packet($data, $logged = null)
{
if (!is_resource($this->fsock) || feof($this->fsock)) {
user_error('Connection closed prematurely');
$this->bitmap = 0;
return false;
}
//if ($this->compress) {
// // the -4 removes the checksum:
// // http://php.net/function.gzcompress#57710
// $data = substr(gzcompress($data), 0, -4);
//}
// 4 (packet length) + 1 (padding length) + 4 (minimal padding amount) == 9
$packet_length = strlen($data) + 9;
// round up to the nearest $this->encrypt_block_size
$packet_length += ($this->encrypt_block_size - 1) * $packet_length % $this->encrypt_block_size;
// subtracting strlen($data) is obvious - subtracting 5 is necessary because of packet_length and padding_length
$padding_length = $packet_length - strlen($data) - 5;
$padding = Crypt_Random::crypt_random_string($padding_length);
// we subtract 4 from packet_length because the packet_length field isn't supposed to include itself
$packet = pack('NCa*', $packet_length - 4, $padding_length, $data . $padding);
$hmac = $this->hmac_create !== false ? $this->hmac_create->hash(pack('Na*', $this->send_seq_no, $packet)) : '';
$this->send_seq_no++;
if ($this->encrypt !== false) {
$packet = $this->encrypt->encrypt($packet);
}
$packet .= $hmac;
$start = strtok(microtime(), ' ') + strtok('');
// http://php.net/microtime#61838
$result = strlen($packet) == fputs($this->fsock, $packet);
$stop = strtok(microtime(), ' ') + strtok('');
if (defined('NET_SSH2_LOGGING')) {
$current = strtok(microtime(), ' ') + strtok('');
$message_number = isset($this->message_numbers[ord($data[0])]) ? $this->message_numbers[ord($data[0])] : 'UNKNOWN (' . ord($data[0]) . ')';
$message_number = '-> ' . $message_number . ' (since last: ' . round($current - $this->last_packet, 4) . ', network: ' . round($stop - $start, 4) . 's)';
$this->_append_log($message_number, isset($logged) ? $logged : $data);
$this->last_packet = $current;
}
return $result;
}
