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AES: Fix broken CFB and disableContinuousBuffer()

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Quoting from petrich's pull request (from which this commit was inspired):

Fixed: Broken CFB in continuous mode when using CRYPT_AES_MODE_MCRYPT (related to: #39 )
Fixed: Multiple calls to enable/disableContinuousBuffer()
Fixed: Some PHP Notice/Warnings about strlen(array())
This commit is contained in:
terrafrost 2013-01-09 17:39:57 -06:00
parent 2ead31dac2
commit d741def23c
1 changed files with 50 additions and 30 deletions
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78
phpseclib/Crypt/AES.php
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@ -214,8 +214,6 @@ class Crypt_AES extends Crypt_Rijndael {
$this->mode = MCRYPT_MODE_CBC;
}
$this->debuffer = $this->enbuffer = '';
break;
default:
switch ($mode) {
@ -317,12 +315,14 @@ class Crypt_AES extends Crypt_Rijndael {
mcrypt_generic_init($this->ecb, $this->key, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0");
}
if (strlen($this->enbuffer)) {
$ciphertext = $plaintext ^ substr($this->encryptIV, strlen($this->enbuffer));
$this->enbuffer.= $ciphertext;
if (strlen($this->enbuffer) == 16) {
$this->encryptIV = $this->enbuffer;
$this->enbuffer = '';
$buffer = &$this->enbuffer['encrypted'];
if (strlen($buffer)) {
$ciphertext = $plaintext ^ substr($this->encryptIV, strlen($buffer));
$buffer.= $ciphertext;
if (strlen($buffer) == 16) {
$this->encryptIV = $buffer;
$buffer = '';
mcrypt_generic_init($this->enmcrypt, $this->key, $this->encryptIV);
}
$plaintext = substr($plaintext, strlen($ciphertext));
@ -331,15 +331,15 @@ class Crypt_AES extends Crypt_Rijndael {
}
$last_pos = strlen($plaintext) & 0xFFFFFFF0;
$ciphertext.= $last_pos ? mcrypt_generic($this->enmcrypt, substr($plaintext, 0, $last_pos)) : '';
if (strlen($plaintext) & 0xF) {
if (strlen($ciphertext)) {
if ($last_pos) {
$ciphertext.= mcrypt_generic($this->enmcrypt, substr($plaintext, 0, $last_pos));
$this->encryptIV = substr($ciphertext, -16);
}
if (strlen($plaintext) & 0xF) {
$this->encryptIV = mcrypt_generic($this->ecb, $this->encryptIV);
$this->enbuffer = substr($plaintext, $last_pos) ^ $this->encryptIV;
$ciphertext.= $this->enbuffer;
$buffer = substr($plaintext, $last_pos) ^ $this->encryptIV;
$ciphertext.= $buffer;
}
return $ciphertext;
@ -392,13 +392,15 @@ class Crypt_AES extends Crypt_Rijndael {
mcrypt_generic_init($this->ecb, $this->key, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0");
}
if (strlen($this->debuffer)) {
$plaintext = $ciphertext ^ substr($this->decryptIV, strlen($this->debuffer));
$buffer = &$this->debuffer['ciphertext'];
$this->debuffer.= substr($ciphertext, 0, strlen($plaintext));
if (strlen($this->debuffer) == 16) {
$this->decryptIV = $this->debuffer;
$this->debuffer = '';
if (strlen($buffer)) {
$plaintext = $ciphertext ^ substr($this->decryptIV, strlen($buffer));
$buffer.= substr($ciphertext, 0, strlen($plaintext));
if (strlen($buffer) == 16) {
$this->decryptIV = $buffer;
$buffer = '';
mcrypt_generic_init($this->demcrypt, $this->key, $this->decryptIV);
}
$ciphertext = substr($ciphertext, strlen($plaintext));
@ -407,15 +409,15 @@ class Crypt_AES extends Crypt_Rijndael {
}
$last_pos = strlen($ciphertext) & 0xFFFFFFF0;
$plaintext.= $last_pos ? mdecrypt_generic($this->demcrypt, substr($ciphertext, 0, $last_pos)) : '';
if ($last_pos) {
$plaintext = mdecrypt_generic($this->demcrypt, substr($ciphertext, 0, $last_pos));
$this->decryptIV = substr($ciphertext, $last_pos - 16, 16);
$this->decryptIV = mcrypt_generic($this->ecb, $this->decryptIV);
}
if (strlen($ciphertext) & 0xF) {
if (strlen($plaintext)) {
$this->decryptIV = substr($ciphertext, $last_pos - 16, 16);
}
$this->decryptIV = mcrypt_generic($this->ecb, $this->decryptIV);
$this->debuffer = substr($ciphertext, $last_pos);
$plaintext.= $this->debuffer ^ $this->decryptIV;
$buffer = substr($ciphertext, $last_pos);
$plaintext.= $buffer ^ $this->decryptIV;
}
return $plaintext;
@ -526,7 +528,7 @@ class Crypt_AES extends Crypt_Rijndael {
// shiftRows + subWord + mixColumns + addRoundKey
// we could loop unroll this and use if statements to do more rounds as necessary, but, in my tests, that yields
// only a marginal improvement. since that also, imho, hinders the readability of the code, i've opted not to do it.
for ($round = 1; $round < $this->Nr; $round++) {
for ($round = 1; $round < $Nr; $round++) {
$state = array(
$t0[$state[0] & 0xFF000000] ^ $t1[$state[1] & 0x00FF0000] ^ $t2[$state[2] & 0x0000FF00] ^ $t3[$state[3] & 0x000000FF] ^ $w[$round][0],
$t0[$state[1] & 0xFF000000] ^ $t1[$state[2] & 0x00FF0000] ^ $t2[$state[3] & 0x0000FF00] ^ $t3[$state[0] & 0x000000FF] ^ $w[$round][1],
@ -586,7 +588,7 @@ class Crypt_AES extends Crypt_Rijndael {
// invShiftRows + invSubBytes + invMixColumns + addRoundKey
for ($round = $this->Nr - 1; $round > 0; $round--) {
for ($round = $Nr - 1; $round > 0; $round--) {
$state = array(
$dt0[$state[0] & 0xFF000000] ^ $dt1[$state[3] & 0x00FF0000] ^ $dt2[$state[2] & 0x0000FF00] ^ $dt3[$state[1] & 0x000000FF] ^ $dw[$round][0],
$dt0[$state[1] & 0xFF000000] ^ $dt1[$state[0] & 0x00FF0000] ^ $dt2[$state[3] & 0x0000FF00] ^ $dt3[$state[2] & 0x000000FF] ^ $dw[$round][1],
@ -605,6 +607,24 @@ class Crypt_AES extends Crypt_Rijndael {
return pack('N*', $state[0], $state[1], $state[2], $state[3]);
}
/**
* Treat consecutive packets as if they are a discontinuous buffer.
*
* The default behavior.
*
* @see Crypt_Rijndael::enableContinuousBuffer()
* @access public
*/
function disableContinuousBuffer()
{
parent::disableContinuousBuffer();
if (CRYPT_AES_MODE == CRYPT_AES_MODE_MCRYPT) {
mcrypt_generic_init($this->enmcrypt, $this->key, $this->iv);
mcrypt_generic_init($this->demcrypt, $this->key, $this->iv);
}
}
}
// vim: ts=4:sw=4:et: