/**
* Default Constructor.
*
* Connects to an SSHv1 server
*
* @param String $host
* @param optional Integer $port
* @param optional Integer $timeout
* @param optional Integer $cipher
* @return SSH1
* @access public
*/
public function __construct($host, $port = 22, $timeout = 10, $cipher = SSH1_CIPHER_3DES)
{
$this->protocol_flags = array(1 => 'SSH1_MSG_DISCONNECT', 2 => 'SSH1_SMSG_PUBLIC_KEY', 3 => 'SSH1_CMSG_SESSION_KEY', 4 => 'SSH1_CMSG_USER', 9 => 'SSH1_CMSG_AUTH_PASSWORD', 10 => 'SSH1_CMSG_REQUEST_PTY', 12 => 'SSH1_CMSG_EXEC_SHELL', 13 => 'SSH1_CMSG_EXEC_CMD', 14 => 'SSH1_SMSG_SUCCESS', 15 => 'SSH1_SMSG_FAILURE', 16 => 'SSH1_CMSG_STDIN_DATA', 17 => 'SSH1_SMSG_STDOUT_DATA', 18 => 'SSH1_SMSG_STDERR_DATA', 19 => 'SSH1_CMSG_EOF', 20 => 'SSH1_SMSG_EXITSTATUS', 33 => 'SSH1_CMSG_EXIT_CONFIRMATION');
$this->_define_array($this->protocol_flags);
$this->fsock = @fsockopen($host, $port, $errno, $errstr, $timeout);
if (!$this->fsock) {
user_error(rtrim("Cannot connect to {$host}. Error {$errno}. {$errstr}"), E_USER_NOTICE);
return;
}
$this->server_identification = $init_line = fgets($this->fsock, 255);
if (defined('SSH1_LOGGING')) {
$this->protocol_flags_log[] = '<-';
$this->protocol_flags_log[] = '->';
if (SSH1_LOGGING == SSH1_LOG_COMPLEX) {
$this->message_log[] = $this->server_identification;
$this->message_log[] = $this->identifier . "\r\n";
}
}
if (!preg_match('#SSH-([0-9\\.]+)-(.+)#', $init_line, $parts)) {
user_error('Can only connect to SSH servers', E_USER_NOTICE);
return;
}
if ($parts[1][0] != 1) {
user_error("Cannot connect to SSH {$parts['1']} servers", E_USER_NOTICE);
return;
}
fputs($this->fsock, $this->identifier . "\r\n");
$response = $this->_get_binary_packet();
if ($response[SSH1_RESPONSE_TYPE] != SSH1_SMSG_PUBLIC_KEY) {
user_error('Expected SSH_SMSG_PUBLIC_KEY', E_USER_NOTICE);
return;
}
$anti_spoofing_cookie = $this->_string_shift($response[SSH1_RESPONSE_DATA], 8);
$this->_string_shift($response[SSH1_RESPONSE_DATA], 4);
$temp = unpack('nlen', $this->_string_shift($response[SSH1_RESPONSE_DATA], 2));
$server_key_public_exponent = new BigInteger($this->_string_shift($response[SSH1_RESPONSE_DATA], ceil($temp['len'] / 8)), 256);
$this->server_key_public_exponent = $server_key_public_exponent;
$temp = unpack('nlen', $this->_string_shift($response[SSH1_RESPONSE_DATA], 2));
$server_key_public_modulus = new BigInteger($this->_string_shift($response[SSH1_RESPONSE_DATA], ceil($temp['len'] / 8)), 256);
$this->server_key_public_modulus = $server_key_public_modulus;
$this->_string_shift($response[SSH1_RESPONSE_DATA], 4);
$temp = unpack('nlen', $this->_string_shift($response[SSH1_RESPONSE_DATA], 2));
$host_key_public_exponent = new BigInteger($this->_string_shift($response[SSH1_RESPONSE_DATA], ceil($temp['len'] / 8)), 256);
$this->host_key_public_exponent = $host_key_public_exponent;
$temp = unpack('nlen', $this->_string_shift($response[SSH1_RESPONSE_DATA], 2));
$host_key_public_modulus = new BigInteger($this->_string_shift($response[SSH1_RESPONSE_DATA], ceil($temp['len'] / 8)), 256);
$this->host_key_public_modulus = $host_key_public_modulus;
$this->_string_shift($response[SSH1_RESPONSE_DATA], 4);
// get a list of the supported ciphers
extract(unpack('Nsupported_ciphers_mask', $this->_string_shift($response[SSH1_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[SSH1_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));
$session_key = '';
for ($i = 0; $i < 32; $i++) {
$session_key .= chr(Random(0, 255));
}
$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[$cipher]) ? $cipher : SSH1_CIPHER_3DES;
$data = pack('C2a*na*N', SSH1_CMSG_SESSION_KEY, $cipher, $anti_spoofing_cookie, 8 * strlen($double_encrypted_session_key), $double_encrypted_session_key, 0);
if (!$this->_send_binary_packet($data)) {
user_error('Error sending SSH_CMSG_SESSION_KEY', E_USER_NOTICE);
return;
}
switch ($cipher) {
//case SSH1_CIPHER_NONE:
// $this->crypto = new Crypt_Null();
// break;
case SSH1_CIPHER_DES:
$this->crypto = new DES();
$this->crypto->disablePadding();
$this->crypto->enableContinuousBuffer();
$this->crypto->setKey(substr($session_key, 0, 8));
break;
case SSH1_CIPHER_3DES:
$this->crypto = new TripleDES(DES_MODE_3CBC);
$this->crypto->disablePadding();
$this->crypto->enableContinuousBuffer();
$this->crypto->setKey(substr($session_key, 0, 24));
break;
//case SSH1_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[SSH1_RESPONSE_TYPE] != SSH1_SMSG_SUCCESS) {
user_error('Expected SSH_SMSG_SUCCESS', E_USER_NOTICE);
return;
}
$this->bitmap = SSH1_MASK_CONSTRUCTOR;
}
/**
* RSAVP1
*
* See {@link http://tools.ietf.org/html/rfc3447#section-5.2.2 RFC3447#section-5.2.2}.
*
* @access private
* @param BigInteger $s
* @return BigInteger
*/
function _rsavp1($s)
{
if ($s->compare($this->zero) < 0 || $s->compare($this->modulus) > 0) {
user_error('Signature representative out of range', E_USER_NOTICE);
return false;
}
return $this->_exponentiate($s);
}
/**
* 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
* @access public
*/
function getServerPublicHostKey()
{
$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, $length);
switch ($this->signature_format) {
case 'ssh-dss':
$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) {
user_error('Invalid signature', E_USER_NOTICE);
return $this->_disconnect(SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
}
$r = new BigInteger($this->_string_shift($signature, 20), 256);
$s = new BigInteger($this->_string_shift($signature, 20), 256);
if ($r->compare($q) >= 0 || $s->compare($q) >= 0) {
user_error('Invalid signature', E_USER_NOTICE);
return $this->_disconnect(SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
}
$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', E_USER_NOTICE);
return $this->_disconnect(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));
$n = new BigInteger($this->_string_shift($server_public_host_key, $temp['length']), -256);
$nLength = $temp['length'];
/*
$temp = unpack('Nlength', $this->_string_shift($signature, 4));
$signature = $this->_string_shift($signature, $temp['length']);
if (!class_exists('RSA')) {
require_once('Crypt/RSA.php');
}
$rsa = new RSA();
$rsa->setSignatureMode(RSA_SIGNATURE_PKCS1);
$rsa->loadKey(array('e' => $e, 'n' => $n), RSA_PUBLIC_FORMAT_RAW);
if (!$rsa->verify($this->exchange_hash, $signature)) {
user_error('Bad server signature', E_USER_NOTICE);
return $this->_disconnect(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) {
user_error('Invalid signature', E_USER_NOTICE);
return $this->_disconnect(SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
}
$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), $nLength - 3 - strlen($h)) . $h;
if ($s != $h) {
user_error('Bad server signature', E_USER_NOTICE);
return $this->_disconnect(SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE);
}
}
return $this->server_public_host_key;
}
