<?php

/**

 * Random_* Compatibility Library

 * for using the new PHP 7 random_* API in PHP 5 projects

 *

 *

 * The MIT License (MIT)

 *

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

 * SOFTWARE.

 */

if (!defined('PHP_VERSION_ID')) {

    // This constant was introduced in PHP 5.2.7

    $RandomCompatversion = array_map('intval', explode('.', PHP_VERSION));

    define(

        'PHP_VERSION_ID',

        $RandomCompatversion[0] * 10000

        + $RandomCompatversion[1] * 100

        + $RandomCompatversion[2]

    );

    $RandomCompatversion = null;

}

/**

 * PHP 7.0.0 and newer have these functions natively.

 */

if (PHP_VERSION_ID >= 70000) {

    return;

}

if (!defined('RANDOM_COMPAT_READ_BUFFER')) {

    define('RANDOM_COMPAT_READ_BUFFER', 8);

}

$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')) {

        } elseif (method_exists('Sodium', 'randombytes_buf')) {

        }

    }

    /**

     * 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;

        }

        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

        }

        // Unset variables after use

        $RandomCompat_basedir = null;

    } else {

        $RandomCompatUrandom = false;

    }

    /**

     * mcrypt_create_iv()

     *

     * We only want to use mcypt_create_iv() if:

     *

     * - random_bytes() hasn't already been defined

     * - 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 we're on Windows, we want to use PHP >= 5.3.7 or else

     *     we get insufficient entropy errors.

     */

    if (

        !is_callable('random_bytes')

        &&

        // Windows on PHP < 5.3.7 is broken, but non-Windows is not known to be.

        (DIRECTORY_SEPARATOR === '/' || PHP_VERSION_ID >= 50307)

        &&

        // Prevent this code from hanging indefinitely on non-Windows;

        // see https://bugs.php.net/bug.php?id=69833

        (

            DIRECTORY_SEPARATOR !== '/' ||

            (PHP_VERSION_ID <= 50609 || PHP_VERSION_ID >= 50613)

        )

        &&

        extension_loaded('mcrypt')

    ) {

        // See random_bytes_mcrypt.php

    }

    $RandomCompatUrandom = null;

    /**

     * 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');

                    // See random_bytes_com_dotnet.php

                }

            } catch (com_exception $e) {

                // Don't try to use it.

            }

        }

        $RandomCompat_disabled_classes = null;

        $RandomCompatCOMtest = null;

    }

    /**

     * throw new Exception

     */

    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.

         *

         * @param mixed $length

         * @throws Exception

         */

        function random_bytes($length)

        {

            unset($length); // Suppress "variable not used" warnings.

            throw new Exception(

                'There is no suitable CSPRNG installed on your system'

            );

        }

    }

}

if (!is_callable('random_int')) {

}

$RandomCompatDIR = null;