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System/SSH/Agent: add support for rsa-sha2-256 / rsa-sha2-512

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This commit is contained in:
terrafrost 2018-11-22 20:47:15 -06:00
parent 431b3570fa
commit 8f2a0e6f0d
1 changed files with 64 additions and 5 deletions
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69
phpseclib/System/SSH/Agent.php
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@ -64,7 +64,7 @@ define('SYSTEM_SSH_AGENT_FAILURE', 5);
define('SYSTEM_SSH_AGENTC_SIGN_REQUEST', 13);
// the SSH1 response is SSH_AGENT_RSA_RESPONSE (4)
define('SYSTEM_SSH_AGENT_SIGN_RESPONSE', 14);
/**#@-*/
/**@+
* Agent forwarding status
@ -77,7 +77,17 @@ define('SYSTEM_SSH_AGENT_FORWARD_NONE', 0);
define('SYSTEM_SSH_AGENT_FORWARD_REQUEST', 1);
// forwarding has been request and is active
define('SYSTEM_SSH_AGENT_FORWARD_ACTIVE', 2);
/**#@-*/
/**@+
* Signature Flags
*
* See https://tools.ietf.org/html/draft-miller-ssh-agent-00#section-5.3
*
* @access private
*/
define('SYSTEM_SSH_AGENT_RSA2_256', 2);
define('SYSTEM_SSH_AGENT_RSA2_512', 4);
/**#@-*/
/**
@ -123,6 +133,16 @@ class System_SSH_Agent_Identity
*/
var $fsock;
/**
* Signature flags
*
* @var int
* @access private
* @see self::sign()
* @see self::setHash()
*/
var $flags = 0;
/**
* Default Constructor.
*
@ -212,6 +232,19 @@ class System_SSH_Agent_Identity
*/
function setHash($hash)
{
$this->flags = 0;
switch ($hash) {
case 'sha1':
break;
case 'sha256':
$this->flags = SYSTEM_SSH_AGENT_RSA2_256;
break;
case 'sha512':
$this->flags = SYSTEM_SSH_AGENT_RSA2_512;
break;
default:
user_error('The only supported hashes for RSA are sha1, sha256 and sha512');
}
}
/**
@ -226,7 +259,7 @@ class System_SSH_Agent_Identity
function sign($message)
{
// the last parameter (currently 0) is for flags and ssh-agent only defines one flag (for ssh-dss): SSH_AGENT_OLD_SIGNATURE
$packet = pack('CNa*Na*N', SYSTEM_SSH_AGENTC_SIGN_REQUEST, strlen($this->key_blob), $this->key_blob, strlen($message), $message, 0);
$packet = pack('CNa*Na*N', SYSTEM_SSH_AGENTC_SIGN_REQUEST, strlen($this->key_blob), $this->key_blob, strlen($message), $message, $this->flags);
$packet = pack('Na*', strlen($packet), $packet);
if (strlen($packet) != fputs($this->fsock, $packet)) {
user_error('Connection closed during signing');
@ -239,9 +272,35 @@ class System_SSH_Agent_Identity
}
$signature_blob = fread($this->fsock, $length - 1);
// the only other signature format defined - ssh-dss - is the same length as ssh-rsa
// the + 12 is for the other various SSH added length fields
return substr($signature_blob, strlen('ssh-rsa') + 12);
$length = current(unpack('N', $this->_string_shift($signature_blob, 4)));
if ($length != strlen($signature_blob)) {
user_error('Malformed signature blob');
}
$length = current(unpack('N', $this->_string_shift($signature_blob, 4)));
if ($length > strlen($signature_blob) + 4) {
user_error('Malformed signature blob');
}
$type = $this->_string_shift($signature_blob, $length);
$this->_string_shift($signature_blob, 4);
return $signature_blob;
}
/**
* String Shift
*
* Inspired by array_shift
*
* @param string $string
* @param int $index
* @return string
* @access private
*/
function _string_shift(&$string, $index = 1)
{
$substr = substr($string, 0, $index);
$string = substr($string, $index);
return $substr;
}
}