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- included a work-around for a bug in Portable OpenSSH 4.4 and earlier whereby faulty key sizes are used for aes256-ctr, aes192-ctr and arcfour256 (thanks, f.dammassa!)

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git-svn-id: http://phpseclib.svn.sourceforge.net/svnroot/phpseclib/trunk@116 21d32557-59b3-4da0-833f-c5933fad653e
This commit is contained in:
Jim Wigginton 2010-08-29 03:27:02 +00:00
parent d07570b0eb
commit a8863e2b3d
1 changed files with 39 additions and 10 deletions
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49
phpseclib/Net/SSH2.php
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@ -60,7 +60,7 @@
* @author Jim Wigginton <terrafrost@php.net>
* @copyright MMVII Jim Wigginton
* @license http://www.gnu.org/licenses/lgpl.txt
* @version $Id: SSH2.php,v 1.49 2010-08-28 17:26:22 terrafrost Exp $
* @version $Id: SSH2.php,v 1.50 2010-08-29 03:27:02 terrafrost Exp $
* @link http://phpseclib.sourceforge.net
*/
@ -563,6 +563,23 @@ class Net_SSH2 {
*/
var $signature_format = '';
/**
* Key size fix
*
* Portable OpenSSH 4.4 and earlier use faulty key sizes for aes256-ctr, aes192-ctr and arcfour256.
* These algorithms could be removed from $encryption_algorithms in Net_SSH2::_key_exchange() but we'll
* adjust the key sizes instead to confirm that the version detection technique we're using is correct.
* If it isn't correct than we'll get decryption / encryption errors. We wouldn't get any errors, in
* contrast, if the algorithms were simply removed, and would never know if the version detection
* technique we were using was correct.
*
* @link http://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/ssh2-aesctr-openssh
* @see Net_SSH2::Net_SSH2()
* @var Boolean
* @access private
*/
var $adjust_key_fix = false;
/**
* Default Constructor.
*
@ -708,6 +725,8 @@ class Net_SSH2 {
return;
}
$this->adjust_key_fix = preg_match('#SSH-' . $matches[1] . '\-OpenSSH_([\d\.]+)#', $this->server_identifier, $matches) && $matches[1] < 4.6;
fputs($this->fsock, $this->identifier . "\r\n");
$response = $this->_get_binary_packet();
@ -866,12 +885,16 @@ class Net_SSH2 {
$decryptKeyLength = 24; // eg. 192 / 8
break;
case 'aes256-cbc':
case 'aes256-ctr':
$decryptKeyLength = 32; // eg. 256 / 8
break;
case 'aes256-ctr':
$decryptKeyLength = !$this->adjust_key_fix ? 32 : 16;
break;
case 'aes192-cbc':
$decryptKeyLength = 24;
break;
case 'aes192-ctr':
$decryptKeyLength = 24; // eg. 192 / 8
$decryptKeyLength = !$this->adjust_key_fix ? 24 : 16;
break;
case 'aes128-cbc':
case 'aes128-ctr':
@ -879,10 +902,10 @@ class Net_SSH2 {
break;
case 'arcfour':
case 'arcfour128':
$decryptKeyLength = 16; // eg. 128 / 8
$decryptKeyLength = 16;
break;
case 'arcfour256':
$decryptKeyLength = 32; // eg. 128 / 8
$decryptKeyLength = !$this->adjust_key_fix ? 32 : 16;
break;
case 'none';
$decryptKeyLength = 0;
@ -901,13 +924,17 @@ class Net_SSH2 {
$encryptKeyLength = 24;
break;
case 'aes256-cbc':
case 'aes256-ctr':
$encryptKeyLength = 32;
break;
case 'aes256-ctr':
$encryptKeyLength = !$this->adjust_key_fix ? 32 : 16;
break;
case 'aes192-cbc':
case 'aes192-ctr':
$encryptKeyLength = 24;
break;
case 'aes192-ctr':
$encryptKeyLength = !$this->adjust_key_fix ? 24 : 16;
break;
case 'aes128-cbc':
case 'aes128-ctr':
$encryptKeyLength = 16;
@ -917,7 +944,7 @@ class Net_SSH2 {
$encryptKeyLength = 16;
break;
case 'arcfour256':
$encryptKeyLength = 32;
$encryptKeyLength = !$this->adjust_key_fix ? 32 : 16;
break;
case 'none';
$encryptKeyLength = 0;
@ -1408,7 +1435,7 @@ class Net_SSH2 {
for ($i = 0; $i < $num_prompts; $i++) {
extract(unpack('Nlength', $this->_string_shift($response, 4)));
// prompt - ie. "Password: "; must not be empty
$this->_string_shift($response, $length); // prompt; must not be empty
$this->_string_shift($response, $length);
$echo = $this->_string_shift($response) != chr(0);
}
*/
@ -1418,9 +1445,10 @@ class Net_SSH2 {
MUST respond with an SSH_MSG_USERAUTH_INFO_RESPONSE message.
*/
// see http://tools.ietf.org/html/rfc4256#section-3.4
$packet = pack('CN', NET_SSH2_MSG_USERAUTH_INFO_RESPONSE, count($responses));
$packet = $logged = pack('CN', NET_SSH2_MSG_USERAUTH_INFO_RESPONSE, count($responses));
for ($i = 0; $i < count($responses); $i++) {
$packet.= pack('Na*', strlen($responses[$i]), $responses[$i]);
$logged.= pack('Na*', strlen('dummy-answer'), 'dummy-answer');
}
if (!$this->_send_binary_packet($packet)) {
@ -1429,6 +1457,7 @@ class Net_SSH2 {
if (defined('NET_SSH2_LOGGING')) {
$this->message_number_log[count($this->message_number_log) - 1] = 'NET_SSH2_MSG_USERAUTH_INFO_RESPONSE';
$this->message_log[count($this->message_log) - 1] = $logged;
}
/*