/**
* Connect to an SSHv1 server
*
* @return bool
* @throws \UnexpectedValueException on receipt of unexpected packets
* @throws \RuntimeException on other errors
* @access private
*/
function _connect()
{
$this->fsock = @fsockopen($this->host, $this->port, $errno, $errstr, $this->connectionTimeout);
if (!$this->fsock) {
throw new \RuntimeException(rtrim("Cannot connect to {$host}. Error {$errno}. {$errstr}"));
}
$this->server_identification = $init_line = fgets($this->fsock, 255);
if (defined('NET_SSH1_LOGGING')) {
$this->_append_log('<-', $this->server_identification);
$this->_append_log('->', $this->identifier . "\r\n");
}
if (!preg_match('#SSH-([0-9\\.]+)-(.+)#', $init_line, $parts)) {
throw new \RuntimeException('Can only connect to SSH servers');
}
if ($parts[1][0] != 1) {
throw new \RuntimeException("Cannot connect to {$parts['1']} servers");
}
fputs($this->fsock, $this->identifier . "\r\n");
$response = $this->_get_binary_packet();
if ($response[self::RESPONSE_TYPE] != NET_SSH1_SMSG_PUBLIC_KEY) {
throw new \UnexpectedValueException('Expected SSH_SMSG_PUBLIC_KEY');
}
$anti_spoofing_cookie = $this->_string_shift($response[self::RESPONSE_DATA], 8);
$this->_string_shift($response[self::RESPONSE_DATA], 4);
$temp = unpack('nlen', $this->_string_shift($response[self::RESPONSE_DATA], 2));
$server_key_public_exponent = new BigInteger($this->_string_shift($response[self::RESPONSE_DATA], ceil($temp['len'] / 8)), 256);
$this->server_key_public_exponent = $server_key_public_exponent;
$temp = unpack('nlen', $this->_string_shift($response[self::RESPONSE_DATA], 2));
$server_key_public_modulus = new BigInteger($this->_string_shift($response[self::RESPONSE_DATA], ceil($temp['len'] / 8)), 256);
$this->server_key_public_modulus = $server_key_public_modulus;
$this->_string_shift($response[self::RESPONSE_DATA], 4);
$temp = unpack('nlen', $this->_string_shift($response[self::RESPONSE_DATA], 2));
$host_key_public_exponent = new BigInteger($this->_string_shift($response[self::RESPONSE_DATA], ceil($temp['len'] / 8)), 256);
$this->host_key_public_exponent = $host_key_public_exponent;
$temp = unpack('nlen', $this->_string_shift($response[self::RESPONSE_DATA], 2));
$host_key_public_modulus = new BigInteger($this->_string_shift($response[self::RESPONSE_DATA], ceil($temp['len'] / 8)), 256);
$this->host_key_public_modulus = $host_key_public_modulus;
$this->_string_shift($response[self::RESPONSE_DATA], 4);
// get a list of the supported ciphers
extract(unpack('Nsupported_ciphers_mask', $this->_string_shift($response[self::RESPONSE_DATA], 4)));
foreach ($this->supported_ciphers as $mask => $name) {
if (($supported_ciphers_mask & 1 << $mask) == 0) {
unset($this->supported_ciphers[$mask]);
}
}
// get a list of the supported authentications
extract(unpack('Nsupported_authentications_mask', $this->_string_shift($response[self::RESPONSE_DATA], 4)));
foreach ($this->supported_authentications as $mask => $name) {
if (($supported_authentications_mask & 1 << $mask) == 0) {
unset($this->supported_authentications[$mask]);
}
}
$session_id = pack('H*', md5($host_key_public_modulus->toBytes() . $server_key_public_modulus->toBytes() . $anti_spoofing_cookie));
$session_key = Random::string(32);
$double_encrypted_session_key = $session_key ^ str_pad($session_id, 32, chr(0));
if ($server_key_public_modulus->compare($host_key_public_modulus) < 0) {
$double_encrypted_session_key = $this->_rsa_crypt($double_encrypted_session_key, array($server_key_public_exponent, $server_key_public_modulus));
$double_encrypted_session_key = $this->_rsa_crypt($double_encrypted_session_key, array($host_key_public_exponent, $host_key_public_modulus));
} else {
$double_encrypted_session_key = $this->_rsa_crypt($double_encrypted_session_key, array($host_key_public_exponent, $host_key_public_modulus));
$double_encrypted_session_key = $this->_rsa_crypt($double_encrypted_session_key, array($server_key_public_exponent, $server_key_public_modulus));
}
$cipher = isset($this->supported_ciphers[$this->cipher]) ? $this->cipher : self::CIPHER_3DES;
$data = pack('C2a*na*N', NET_SSH1_CMSG_SESSION_KEY, $cipher, $anti_spoofing_cookie, 8 * strlen($double_encrypted_session_key), $double_encrypted_session_key, 0);
if (!$this->_send_binary_packet($data)) {
throw new \RuntimeException('Error sending SSH_CMSG_SESSION_KEY');
}
switch ($cipher) {
//case self::CIPHER_NONE:
// $this->crypto = new \phpseclib\Crypt\Null();
// break;
case self::CIPHER_DES:
$this->crypto = new DES();
$this->crypto->disablePadding();
$this->crypto->enableContinuousBuffer();
$this->crypto->setKey(substr($session_key, 0, 8));
break;
case self::CIPHER_3DES:
$this->crypto = new TripleDES(TripleDES::MODE_3CBC);
$this->crypto->disablePadding();
$this->crypto->enableContinuousBuffer();
$this->crypto->setKey(substr($session_key, 0, 24));
break;
//case self::CIPHER_RC4:
// $this->crypto = new RC4();
// $this->crypto->enableContinuousBuffer();
// $this->crypto->setKey(substr($session_key, 0, 16));
// break;
}
$response = $this->_get_binary_packet();
if ($response[self::RESPONSE_TYPE] != NET_SSH1_SMSG_SUCCESS) {
throw new \UnexpectedValueException('Expected SSH_SMSG_SUCCESS');
}
$this->bitmap = self::MASK_CONNECTED;
return true;
}
/**
* Returns the server public host key.
*
* Caching this the first time you connect to a server and checking the result on subsequent connections
* is recommended. Returns false if the server signature is not signed correctly with the public host key.
*
* @return mixed
* @throws \RuntimeException on badly formatted keys
* @throws \phpseclib\Exception\NoSupportedAlgorithmsException when the key isn't in a supported format
* @access public
*/
function getServerPublicHostKey()
{
if (!($this->bitmap & self::MASK_CONSTRUCTOR)) {
if (!$this->_connect()) {
return false;
}
}
$signature = $this->signature;
$server_public_host_key = $this->server_public_host_key;
extract(unpack('Nlength', $this->_string_shift($server_public_host_key, 4)));
$this->_string_shift($server_public_host_key, $length);
if ($this->signature_validated) {
return $this->bitmap ? $this->signature_format . ' ' . base64_encode($this->server_public_host_key) : false;
}
$this->signature_validated = true;
switch ($this->signature_format) {
case 'ssh-dss':
$zero = new BigInteger();
$temp = unpack('Nlength', $this->_string_shift($server_public_host_key, 4));
$p = new BigInteger($this->_string_shift($server_public_host_key, $temp['length']), -256);
$temp = unpack('Nlength', $this->_string_shift($server_public_host_key, 4));
$q = new BigInteger($this->_string_shift($server_public_host_key, $temp['length']), -256);
$temp = unpack('Nlength', $this->_string_shift($server_public_host_key, 4));
$g = new BigInteger($this->_string_shift($server_public_host_key, $temp['length']), -256);
$temp = unpack('Nlength', $this->_string_shift($server_public_host_key, 4));
$y = new BigInteger($this->_string_shift($server_public_host_key, $temp['length']), -256);
/* The value for 'dss_signature_blob' is encoded as a string containing
r, followed by s (which are 160-bit integers, without lengths or
padding, unsigned, and in network byte order). */
$temp = unpack('Nlength', $this->_string_shift($signature, 4));
if ($temp['length'] != 40) {
$this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
throw new \RuntimeException('Invalid signature');
}
$r = new BigInteger($this->_string_shift($signature, 20), 256);
$s = new BigInteger($this->_string_shift($signature, 20), 256);
switch (true) {
case $r->equals($zero):
case $r->compare($q) >= 0:
case $s->equals($zero):
case $s->compare($q) >= 0:
$this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
throw new \RuntimeException('Invalid signature');
}
$w = $s->modInverse($q);
$u1 = $w->multiply(new BigInteger(sha1($this->exchange_hash), 16));
list(, $u1) = $u1->divide($q);
$u2 = $w->multiply($r);
list(, $u2) = $u2->divide($q);
$g = $g->modPow($u1, $p);
$y = $y->modPow($u2, $p);
$v = $g->multiply($y);
list(, $v) = $v->divide($p);
list(, $v) = $v->divide($q);
if (!$v->equals($r)) {
//user_error('Bad server signature');
return $this->_disconnect(NET_SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE);
}
break;
case 'ssh-rsa':
$temp = unpack('Nlength', $this->_string_shift($server_public_host_key, 4));
$e = new BigInteger($this->_string_shift($server_public_host_key, $temp['length']), -256);
$temp = unpack('Nlength', $this->_string_shift($server_public_host_key, 4));
$rawN = $this->_string_shift($server_public_host_key, $temp['length']);
$n = new BigInteger($rawN, -256);
$nLength = strlen(ltrim($rawN, ""));
/*
$temp = unpack('Nlength', $this->_string_shift($signature, 4));
$signature = $this->_string_shift($signature, $temp['length']);
$rsa = new RSA();
$rsa->setSignatureMode(RSA::SIGNATURE_PKCS1);
$rsa->load(array('e' => $e, 'n' => $n), 'raw');
if (!$rsa->verify($this->exchange_hash, $signature)) {
//user_error('Bad server signature');
return $this->_disconnect(NET_SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE);
}
*/
$temp = unpack('Nlength', $this->_string_shift($signature, 4));
$s = new BigInteger($this->_string_shift($signature, $temp['length']), 256);
// validate an RSA signature per "8.2 RSASSA-PKCS1-v1_5", "5.2.2 RSAVP1", and "9.1 EMSA-PSS" in the
// following URL:
// ftp://ftp.rsasecurity.com/pub/pkcs/pkcs-1/pkcs-1v2-1.pdf
// also, see SSHRSA.c (rsa2_verifysig) in PuTTy's source.
if ($s->compare(new BigInteger()) < 0 || $s->compare($n->subtract(new BigInteger(1))) > 0) {
$this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
throw new \RuntimeException('Invalid signature');
}
$s = $s->modPow($e, $n);
$s = $s->toBytes();
$h = pack('N4H*', 0x302130, 0x906052b, 0xe03021a, 0x5000414, sha1($this->exchange_hash));
$h = chr(0x1) . str_repeat(chr(0xff), $nLength - 2 - strlen($h)) . $h;
if ($s != $h) {
//user_error('Bad server signature');
return $this->_disconnect(NET_SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE);
}
break;
default:
$this->_disconnect(NET_SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE);
throw new NoSupportedAlgorithmsException('Unsupported signature format');
}
return $this->signature_format . ' ' . base64_encode($this->server_public_host_key);
}
