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<?php | |
class PasswordHash { | |
var $itoa64; | |
var $iteration_count_log2; | |
var $portable_hashes; | |
var $random_state; | |
function __construct($iteration_count_log2, $portable_hashes) | |
{ | |
$this->itoa64 = './0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'; | |
if ($iteration_count_log2 < 4 || $iteration_count_log2 > 31) | |
$iteration_count_log2 = 8; | |
$this->iteration_count_log2 = $iteration_count_log2; | |
$this->portable_hashes = $portable_hashes; | |
$this->random_state = microtime(); | |
if (function_exists('getmypid')) | |
$this->random_state .= getmypid(); | |
} | |
function PasswordHash($iteration_count_log2, $portable_hashes) | |
{ | |
self::__construct($iteration_count_log2, $portable_hashes); | |
} | |
private function get_random_bytes($count) | |
{ | |
$output = ''; | |
if (@is_readable('/dev/urandom') && | |
($fh = @fopen('/dev/urandom', 'rb'))) { | |
$output = fread($fh, $count); | |
fclose($fh); | |
} | |
if (strlen($output) < $count) { | |
$output = ''; | |
for ($i = 0; $i < $count; $i += 16) { | |
$this->random_state = | |
md5(microtime() . $this->random_state); | |
$output .= md5($this->random_state, TRUE); | |
} | |
$output = substr($output, 0, $count); | |
} | |
return $output; | |
} | |
private function encode64($input, $count) | |
{ | |
$output = ''; | |
$i = 0; | |
do { | |
$value = ord($input[$i++]); | |
$output .= $this->itoa64[$value & 0x3f]; | |
if ($i < $count) | |
$value |= ord($input[$i]) << 8; | |
$output .= $this->itoa64[($value >> 6) & 0x3f]; | |
if ($i++ >= $count) | |
break; | |
if ($i < $count) | |
$value |= ord($input[$i]) << 16; | |
$output .= $this->itoa64[($value >> 12) & 0x3f]; | |
if ($i++ >= $count) | |
break; | |
$output .= $this->itoa64[($value >> 18) & 0x3f]; | |
} while ($i < $count); | |
return $output; | |
} | |
private function gensalt_private($input) | |
{ | |
$output = '$P$'; | |
$output .= $this->itoa64[min($this->iteration_count_log2 + | |
((PHP_VERSION >= '5') ? 5 : 3), 30)]; | |
$output .= $this->encode64($input, 6); | |
return $output; | |
} | |
private function crypt_private($password, $setting) | |
{ | |
$output = '*0'; | |
if (substr($setting, 0, 2) === $output) | |
$output = '*1'; | |
$id = substr($setting, 0, 3); | |
# We use "$P$", phpBB3 uses "$H$" for the same thing | |
if ($id !== '$P$' && $id !== '$H$') | |
return $output; | |
$count_log2 = strpos($this->itoa64, $setting[3]); | |
if ($count_log2 < 7 || $count_log2 > 30) | |
return $output; | |
$count = 1 << $count_log2; | |
$salt = substr($setting, 4, 8); | |
if (strlen($salt) !== 8) | |
return $output; | |
# We were kind of forced to use MD5 here since it's the only | |
# cryptographic primitive that was available in all versions | |
# of PHP in use. To implement our own low-level crypto in PHP | |
# would have resulted in much worse performance and | |
# consequently in lower iteration counts and hashes that are | |
# quicker to crack (by non-PHP code). | |
$hash = md5($salt . $password, TRUE); | |
do { | |
$hash = md5($hash . $password, TRUE); | |
} while (--$count); | |
$output = substr($setting, 0, 12); | |
$output .= $this->encode64($hash, 16); | |
return $output; | |
} | |
private function gensalt_blowfish($input) | |
{ | |
# This one needs to use a different order of characters and a | |
# different encoding scheme from the one in encode64() above. | |
# We care because the last character in our encoded string will | |
# only represent 2 bits. While two known implementations of | |
# bcrypt will happily accept and correct a salt string which | |
# has the 4 unused bits set to non-zero, we do not want to take | |
# chances and we also do not want to waste an additional byte | |
# of entropy. | |
$itoa64 = './ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'; | |
$output = '$2a$'; | |
$output .= chr(ord('0') + $this->iteration_count_log2 / 10); | |
$output .= chr(ord('0') + $this->iteration_count_log2 % 10); | |
$output .= '$'; | |
$i = 0; | |
do { | |
$c1 = ord($input[$i++]); | |
$output .= $itoa64[$c1 >> 2]; | |
$c1 = ($c1 & 0x03) << 4; | |
if ($i >= 16) { | |
$output .= $itoa64[$c1]; | |
break; | |
} | |
$c2 = ord($input[$i++]); | |
$c1 |= $c2 >> 4; | |
$output .= $itoa64[$c1]; | |
$c1 = ($c2 & 0x0f) << 2; | |
$c2 = ord($input[$i++]); | |
$c1 |= $c2 >> 6; | |
$output .= $itoa64[$c1]; | |
$output .= $itoa64[$c2 & 0x3f]; | |
} while (1); | |
return $output; | |
} | |
public function HashPassword($password) | |
{ | |
$random = ''; | |
if (CRYPT_BLOWFISH === 1 && !$this->portable_hashes) { | |
$random = $this->get_random_bytes(16); | |
$hash = | |
crypt($password, $this->gensalt_blowfish($random)); | |
if (strlen($hash) === 60) | |
return $hash; | |
} | |
if (strlen($random) < 6) | |
$random = $this->get_random_bytes(6); | |
$hash = | |
$this->crypt_private($password, | |
$this->gensalt_private($random)); | |
if (strlen($hash) === 34) | |
return $hash; | |
# Returning '*' on error is safe here, but would _not_ be safe | |
# in a crypt(3)-like function used _both_ for generating new | |
# hashes and for validating passwords against existing hashes. | |
return '*'; | |
} | |
public function CheckPassword($password, $stored_hash) | |
{ | |
$hash = $this->crypt_private($password, $stored_hash); | |
if ($hash[0] === '*') | |
$hash = crypt($password, $stored_hash); | |
# This is not constant-time. In order to keep the code simple, | |
# for timing safety we currently rely on the salts being | |
# unpredictable, which they are at least in the non-fallback | |
# cases (that is, when we use /dev/urandom and bcrypt). | |
return $hash === $stored_hash; | |
} | |
} |
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