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Fixed CFB Decrypt(). Fixed OFB warnings

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Fixed/rewritten: Decrypt() in CFB mode to work clean with enableContinuousBuffer()

Fixed: PHP's strlen(array()) warning in OFB mode,

Fixed: disableContinuousBuffer() clear's now also the $enbuffer/$debuffer arrays so that multiple calls to enable/disableContinuousBuffer() will work without old buffers
This commit is contained in:
Hans-Jürgen Petrich 2013-01-05 16:23:35 +07:00
parent 29c69808ae
commit d1f71cc5a7
1 changed files with 76 additions and 61 deletions
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137
phpseclib/Crypt/Rijndael.php
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@ -387,7 +387,7 @@ class Crypt_Rijndael {
* @var String
* @access private
*/
var $enbuffer = array('encrypted' => '', 'xor' => '');
var $enbuffer = array('encrypted' => '', 'xor' => '', 'pos' => 0);
/**
* Decryption buffer for CTR, OFB and CFB modes
@ -396,7 +396,7 @@ class Crypt_Rijndael {
* @var String
* @access private
*/
var $debuffer = array('ciphertext' => '');
var $debuffer = array('ciphertext' => '', 'xor' => '', 'pos' => 0);
/**
* Default Constructor.
@ -763,42 +763,46 @@ class Crypt_Rijndael {
}
break;
case CRYPT_RIJNDAEL_MODE_CFB:
if (strlen($buffer['xor'])) {
$ciphertext = $plaintext ^ $buffer['xor'];
$iv = $buffer['encrypted'] . $ciphertext;
$start = strlen($ciphertext);
$buffer['encrypted'].= $ciphertext;
$buffer['xor'] = substr($buffer['xor'], strlen($ciphertext));
} else {
$ciphertext = '';
$iv = $this->encryptIV;
$start = 0;
}
$iv = $this->encryptIV;
$pos = $this->continuousBuffer === true ? $buffer['pos'] : 0;
$len = strlen($plaintext);
for ($i = $start; $i < strlen($plaintext); $i+=$block_size) {
$block = substr($plaintext, $i, $block_size);
$xor = $this->_encryptBlock($iv);
$iv = $block ^ $xor;
if ($continuousBuffer && strlen($iv) != $block_size) {
$buffer = array(
'encrypted' => $iv,
'xor' => substr($xor, strlen($iv))
);
for ($i=0; $pos && $len; --$len, ++$i)
{
$iv[$pos] = $iv[$pos] ^ $plaintext[$i];
$ciphertext .= $iv[$pos];
$pos = ($pos+1) % $block_size;
}
$ciphertext.= $iv;
}
for (; $len >= $block_size; $len-=$block_size, $i+=$block_size)
{
$iv = $this->_encryptBlock($iv) ^ substr($plaintext, $i, $block_size);
$ciphertext .= $iv;
}
if ($len)
{
$iv = $this->_encryptBlock($iv);
while ($len--)
{
$iv[$pos] = $iv[$pos] ^ $plaintext[$i];
$ciphertext .= $iv[$pos];
if ($this->continuousBuffer) {
$this->encryptIV = $iv;
}
++$i;
++$pos;
}
}
if($this->continuousBuffer)
{
$this->encryptIV = $iv;
$buffer['pos'] = $pos;
}
break;
case CRYPT_RIJNDAEL_MODE_OFB:
$xor = $this->encryptIV;
if (strlen($buffer)) {
if (strlen($buffer['xor'])) {
for ($i = 0; $i < strlen($plaintext); $i+=$block_size) {
$xor = $this->_encryptBlock($xor);
$buffer.= $xor;
$key = $this->_string_shift($buffer, $block_size);
$buffer['xor'].= $xor;
$key = $this->_string_shift($buffer['xor'], $block_size);
$ciphertext.= substr($plaintext, $i, $block_size) ^ $key;
}
} else {
@ -811,7 +815,7 @@ class Crypt_Rijndael {
if ($this->continuousBuffer) {
$this->encryptIV = $xor;
if ($start = strlen($plaintext) % $block_size) {
$buffer = substr($key, $start) . $buffer;
$buffer['xor'] = substr($key, $start) . $buffer['xor'];
}
}
}
@ -884,42 +888,51 @@ class Crypt_Rijndael {
}
break;
case CRYPT_RIJNDAEL_MODE_CFB:
if (strlen($buffer['ciphertext'])) {
$plaintext = $ciphertext ^ substr($this->decryptIV, strlen($buffer['ciphertext']));
$buffer['ciphertext'].= substr($ciphertext, 0, strlen($plaintext));
if (strlen($buffer['ciphertext']) == $block_size) {
$xor = $this->_encryptBlock($buffer['ciphertext']);
$buffer['ciphertext'] = '';
}
$start = strlen($plaintext);
$block = $this->decryptIV;
} else {
$plaintext = '';
$xor = $this->_encryptBlock($this->decryptIV);
$start = 0;
}
$iv = $this->decryptIV;
$pos = $this->continuousBuffer === true ? $buffer['pos'] : 0;
$len = strlen($ciphertext);
for ($i = $start; $i < strlen($ciphertext); $i+=$block_size) {
$block = substr($ciphertext, $i, $block_size);
$plaintext.= $block ^ $xor;
if ($continuousBuffer && strlen($block) != $block_size) {
$buffer['ciphertext'].= $block;
$block = $xor;
} else if (strlen($block) == $block_size) {
$xor = $this->_encryptBlock($block);
// cfb routines inspired by: http://cvs.openssl.org/fileview?f=openssl/crypto/modes/cfb128.c&v=1.3.2.2.2.1
for ($i=0; $pos && $len; --$len, ++$i)
{
$plaintext .= $iv[$pos] ^ $ciphertext[$i];
$iv[$pos] = $ciphertext[$i];
$pos = ($pos+1) % $block_size;
}
for (; $len >= $block_size; $len-=$block_size, $i+=$block_size)
{
$iv = $this->_encryptBlock($iv);
$cb = substr($ciphertext, $i, $block_size);
$plaintext .= $iv ^ $cb;
$iv = $cb;
}
if ($len)
{
$iv = $this->_encryptBlock($iv);
while ($len--)
{
$plaintext .= $iv[$pos] ^ $ciphertext[$i];
$iv[$pos] = $ciphertext[$i];
++$i;
++$pos;
}
}
if ($this->continuousBuffer)
{
$this->decryptIV = $iv;
$buffer['pos'] = $pos;
}
}
if ($this->continuousBuffer) {
$this->decryptIV = $block;
}
break;
case CRYPT_RIJNDAEL_MODE_OFB:
$xor = $this->decryptIV;
if (strlen($buffer)) {
if (strlen($buffer['xor'])) {
for ($i = 0; $i < strlen($ciphertext); $i+=$block_size) {
$xor = $this->_encryptBlock($xor);
$buffer.= $xor;
$key = $this->_string_shift($buffer, $block_size);
$buffer['xor'].= $xor;
$key = $this->_string_shift($buffer['xor'], $block_size);
$plaintext.= substr($ciphertext, $i, $block_size) ^ $key;
}
} else {
@ -932,7 +945,7 @@ class Crypt_Rijndael {
if ($this->continuousBuffer) {
$this->decryptIV = $xor;
if ($start = strlen($ciphertext) % $block_size) {
$buffer = substr($key, $start) . $buffer;
$buffer['xor'] = substr($key, $start) . $buffer['xor'];
}
}
}
@ -1454,6 +1467,8 @@ class Crypt_Rijndael {
$this->continuousBuffer = false;
$this->encryptIV = $this->iv;
$this->decryptIV = $this->iv;
$this->enbuffer = array('encrypted' => '', 'xor' => '', 'pos' => 0);
$this->debuffer = array('ciphertext' => '', 'xor' => '', 'pos' => 0);
}
/**