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Merge pull request #122 from Slamdunk/minor_beauty
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Replace Nested Conditional with Guard Clauses
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@paragonie-scott
paragonie-scott authored Feb 3, 2017
2 parents 7e4afae + 2a3b877 commit 1b6a67c
Showing 1 changed file with 142 additions and 140 deletions.
282 changes: 142 additions & 140 deletions lib/random.php
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Original file line number Diff line number Diff line change
Expand Up @@ -44,171 +44,173 @@
/**
* PHP 7.0.0 and newer have these functions natively.
*/
if (PHP_VERSION_ID < 70000) {
if (!defined('RANDOM_COMPAT_READ_BUFFER')) {
define('RANDOM_COMPAT_READ_BUFFER', 8);
}
if (PHP_VERSION_ID >= 70000) {
return;
}

$RandomCompatDIR = dirname(__FILE__);
if (!defined('RANDOM_COMPAT_READ_BUFFER')) {
define('RANDOM_COMPAT_READ_BUFFER', 8);
}

require_once $RandomCompatDIR.'/byte_safe_strings.php';
require_once $RandomCompatDIR.'/cast_to_int.php';
require_once $RandomCompatDIR.'/error_polyfill.php';
$RandomCompatDIR = dirname(__FILE__);

if (!is_callable('random_bytes')) {
/**
* PHP 5.2.0 - 5.6.x way to implement random_bytes()
*
* We use conditional statements here to define the function in accordance
* to the operating environment. It's a micro-optimization.
*
* In order of preference:
* 1. Use libsodium if available.
* 2. fread() /dev/urandom if available (never on Windows)
* 3. mcrypt_create_iv($bytes, MCRYPT_DEV_URANDOM)
* 4. COM('CAPICOM.Utilities.1')->GetRandom()
*
* See RATIONALE.md for our reasoning behind this particular order
*/
if (extension_loaded('libsodium')) {
// See random_bytes_libsodium.php
if (PHP_VERSION_ID >= 50300 && is_callable('\\Sodium\\randombytes_buf')) {
require_once $RandomCompatDIR.'/random_bytes_libsodium.php';
} elseif (method_exists('Sodium', 'randombytes_buf')) {
require_once $RandomCompatDIR.'/random_bytes_libsodium_legacy.php';
}
require_once $RandomCompatDIR.'/byte_safe_strings.php';
require_once $RandomCompatDIR.'/cast_to_int.php';
require_once $RandomCompatDIR.'/error_polyfill.php';

if (!is_callable('random_bytes')) {
/**
* PHP 5.2.0 - 5.6.x way to implement random_bytes()
*
* We use conditional statements here to define the function in accordance
* to the operating environment. It's a micro-optimization.
*
* In order of preference:
* 1. Use libsodium if available.
* 2. fread() /dev/urandom if available (never on Windows)
* 3. mcrypt_create_iv($bytes, MCRYPT_DEV_URANDOM)
* 4. COM('CAPICOM.Utilities.1')->GetRandom()
*
* See RATIONALE.md for our reasoning behind this particular order
*/
if (extension_loaded('libsodium')) {
// See random_bytes_libsodium.php
if (PHP_VERSION_ID >= 50300 && is_callable('\\Sodium\\randombytes_buf')) {
require_once $RandomCompatDIR.'/random_bytes_libsodium.php';
} elseif (method_exists('Sodium', 'randombytes_buf')) {
require_once $RandomCompatDIR.'/random_bytes_libsodium_legacy.php';
}
}

/**
* Reading directly from /dev/urandom:
*/
if (DIRECTORY_SEPARATOR === '/') {
// DIRECTORY_SEPARATOR === '/' on Unix-like OSes -- this is a fast
// way to exclude Windows.
$RandomCompatUrandom = true;
$RandomCompat_basedir = ini_get('open_basedir');

if (!empty($RandomCompat_basedir)) {
$RandomCompat_open_basedir = explode(
PATH_SEPARATOR,
strtolower($RandomCompat_basedir)
);
$RandomCompatUrandom = (array() !== array_intersect(
array('/dev', '/dev/', '/dev/urandom'),
$RandomCompat_open_basedir
));
$RandomCompat_open_basedir = null;
}
/**
* Reading directly from /dev/urandom:
*/
if (DIRECTORY_SEPARATOR === '/') {
// DIRECTORY_SEPARATOR === '/' on Unix-like OSes -- this is a fast
// way to exclude Windows.
$RandomCompatUrandom = true;
$RandomCompat_basedir = ini_get('open_basedir');

if (
!is_callable('random_bytes')
&&
$RandomCompatUrandom
&&
@is_readable('/dev/urandom')
) {
// Error suppression on is_readable() in case of an open_basedir
// or safe_mode failure. All we care about is whether or not we
// can read it at this point. If the PHP environment is going to
// panic over trying to see if the file can be read in the first
// place, that is not helpful to us here.

// See random_bytes_dev_urandom.php
require_once $RandomCompatDIR.'/random_bytes_dev_urandom.php';
}
// Unset variables after use
$RandomCompat_basedir = null;
} else {
$RandomCompatUrandom = false;
if (!empty($RandomCompat_basedir)) {
$RandomCompat_open_basedir = explode(
PATH_SEPARATOR,
strtolower($RandomCompat_basedir)
);
$RandomCompatUrandom = (array() !== array_intersect(
array('/dev', '/dev/', '/dev/urandom'),
$RandomCompat_open_basedir
));
$RandomCompat_open_basedir = null;
}

/**
* mcrypt_create_iv()
*
* We only want to use mcypt_create_iv() if:
*
* - random_bytes() hasn't already been defined
* - PHP >= 5.3.7
* - the mcrypt extensions is loaded
* - One of these two conditions is true:
* - We're on Windows (DIRECTORY_SEPARATOR !== '/')
* - We're not on Windows and /dev/urandom is readabale
* (i.e. we're not in a chroot jail)
* - Special case:
* - If we're not on Windows, but the PHP version is between
* 5.6.10 and 5.6.12, we don't want to use mcrypt. It will
* hang indefinitely. This is bad.
*/
if (
!is_callable('random_bytes')
&&
PHP_VERSION_ID >= 50307
$RandomCompatUrandom
&&
extension_loaded('mcrypt')
@is_readable('/dev/urandom')
) {
// Prevent this code from hanging indefinitely on non-Windows;
// see https://bugs.php.net/bug.php?id=69833
if (
DIRECTORY_SEPARATOR !== '/' ||
(PHP_VERSION_ID <= 50609 || PHP_VERSION_ID >= 50613)
) {
// See random_bytes_mcrypt.php
require_once $RandomCompatDIR.'/random_bytes_mcrypt.php';
}
// Error suppression on is_readable() in case of an open_basedir
// or safe_mode failure. All we care about is whether or not we
// can read it at this point. If the PHP environment is going to
// panic over trying to see if the file can be read in the first
// place, that is not helpful to us here.

// See random_bytes_dev_urandom.php
require_once $RandomCompatDIR.'/random_bytes_dev_urandom.php';
}
$RandomCompatUrandom = null;
// Unset variables after use
$RandomCompat_basedir = null;
} else {
$RandomCompatUrandom = false;
}

/**
* This is a Windows-specific fallback, for when the mcrypt extension
* isn't loaded.
*/
/**
* mcrypt_create_iv()
*
* We only want to use mcypt_create_iv() if:
*
* - random_bytes() hasn't already been defined
* - PHP >= 5.3.7
* - the mcrypt extensions is loaded
* - One of these two conditions is true:
* - We're on Windows (DIRECTORY_SEPARATOR !== '/')
* - We're not on Windows and /dev/urandom is readabale
* (i.e. we're not in a chroot jail)
* - Special case:
* - If we're not on Windows, but the PHP version is between
* 5.6.10 and 5.6.12, we don't want to use mcrypt. It will
* hang indefinitely. This is bad.
*/
if (
!is_callable('random_bytes')
&&
PHP_VERSION_ID >= 50307
&&
extension_loaded('mcrypt')
) {
// Prevent this code from hanging indefinitely on non-Windows;
// see https://bugs.php.net/bug.php?id=69833
if (
!is_callable('random_bytes')
&&
extension_loaded('com_dotnet')
&&
class_exists('COM')
DIRECTORY_SEPARATOR !== '/' ||
(PHP_VERSION_ID <= 50609 || PHP_VERSION_ID >= 50613)
) {
$RandomCompat_disabled_classes = preg_split(
'#\s*,\s*#',
strtolower(ini_get('disable_classes'))
);
// See random_bytes_mcrypt.php
require_once $RandomCompatDIR.'/random_bytes_mcrypt.php';
}
}
$RandomCompatUrandom = null;

if (!in_array('com', $RandomCompat_disabled_classes)) {
try {
$RandomCompatCOMtest = new COM('CAPICOM.Utilities.1');
if (method_exists($RandomCompatCOMtest, 'GetRandom')) {
// See random_bytes_com_dotnet.php
require_once $RandomCompatDIR.'/random_bytes_com_dotnet.php';
}
} catch (com_exception $e) {
// Don't try to use it.
/**
* This is a Windows-specific fallback, for when the mcrypt extension
* isn't loaded.
*/
if (
!is_callable('random_bytes')
&&
extension_loaded('com_dotnet')
&&
class_exists('COM')
) {
$RandomCompat_disabled_classes = preg_split(
'#\s*,\s*#',
strtolower(ini_get('disable_classes'))
);

if (!in_array('com', $RandomCompat_disabled_classes)) {
try {
$RandomCompatCOMtest = new COM('CAPICOM.Utilities.1');
if (method_exists($RandomCompatCOMtest, 'GetRandom')) {
// See random_bytes_com_dotnet.php
require_once $RandomCompatDIR.'/random_bytes_com_dotnet.php';
}
} catch (com_exception $e) {
// Don't try to use it.
}
$RandomCompat_disabled_classes = null;
$RandomCompatCOMtest = null;
}
$RandomCompat_disabled_classes = null;
$RandomCompatCOMtest = null;
}

/**
* throw new Exception
*/
if (!is_callable('random_bytes')) {
/**
* throw new Exception
* We don't have any more options, so let's throw an exception right now
* and hope the developer won't let it fail silently.
*/
if (!is_callable('random_bytes')) {
/**
* We don't have any more options, so let's throw an exception right now
* and hope the developer won't let it fail silently.
*/
function random_bytes($length)
{
throw new Exception(
'There is no suitable CSPRNG installed on your system'
);
}
function random_bytes($length)
{
throw new Exception(
'There is no suitable CSPRNG installed on your system'
);
}
}
}

if (!is_callable('random_int')) {
require_once $RandomCompatDIR.'/random_int.php';
}

$RandomCompatDIR = null;
if (!is_callable('random_int')) {
require_once $RandomCompatDIR.'/random_int.php';
}

$RandomCompatDIR = null;

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