bug #470, use a dedicated lib to generate random bytes

1 files changed, 197 insertions, 0 deletions

diff --git a/include/random_compat/random.php b/include/random_compat/random.php
new file mode 100644
index 000000000..a8802597d
--- /dev/null
+++ b/include/random_compat/random.php
@@ -0,0 +1,197 @@
+<?php
+/**
+ * Random_* Compatibility Library
+ * for using the new PHP 7 random_* API in PHP 5 projects
+ *
+ * @version 2.0.2
+ * @released 2016-04-03
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2015 Paragon Initiative Enterprises
+ *
+ * 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 = explode('.', PHP_VERSION);
+    define(
+        'PHP_VERSION_ID',
+        $RandomCompatversion[0] * 10000
+        + $RandomCompatversion[1] * 100
+        + $RandomCompatversion[2]
+    );
+    $RandomCompatversion = null;
+}
+
+if (PHP_VERSION_ID < 70000) {
+
+    if (!defined('RANDOM_COMPAT_READ_BUFFER')) {
+        define('RANDOM_COMPAT_READ_BUFFER', 8);
+    }
+
+    $RandomCompatDIR = dirname(__FILE__);
+
+    require_once $RandomCompatDIR.'/byte_safe_strings.php';
+    require_once $RandomCompatDIR.'/cast_to_int.php';
+    require_once $RandomCompatDIR.'/error_polyfill.php';
+
+    if (!function_exists('random_bytes')) {
+        /**
+         * PHP 5.2.0 - 5.6.x way to implement random_bytes()
+         *
+         * We use conditional statements here to define the function in accordance
+         * to the operating environment. It's a micro-optimization.
+         *
+         * In order of preference:
+         *   1. Use libsodium if available.
+         *   2. fread() /dev/urandom if available (never on Windows)
+         *   3. mcrypt_create_iv($bytes, MCRYPT_DEV_URANDOM)
+         *   4. COM('CAPICOM.Utilities.1')->GetRandom()
+         *   5. openssl_random_pseudo_bytes() (absolute last resort)
+         *
+         * See ERRATA.md for our reasoning behind this particular order
+         */
+        if (extension_loaded('libsodium')) {
+            // See random_bytes_libsodium.php
+            if (PHP_VERSION_ID >= 50300 && function_exists('\\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;
+            }
+
+            if (
+                !function_exists('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;
+        }
+
+        /**
+         * mcrypt_create_iv()
+         */
+        if (
+            !function_exists('random_bytes')
+            &&
+            PHP_VERSION_ID >= 50307
+            &&
+            extension_loaded('mcrypt')
+            &&
+            (DIRECTORY_SEPARATOR !== '/' || $RandomCompatUrandom)
+        ) {
+            // 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';
+            }
+        }
+        $RandomCompatUrandom = null;
+
+        if (
+            !function_exists('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;
+            $RandomCompatCOMtest = null;
+        }
+
+        /**
+         * throw new Exception
+         */
+        if (!function_exists('random_bytes')) {
+            /**
+             * We don't have any more options, so let's throw an exception right now
+             * and hope the developer won't let it fail silently.
+             */
+            function random_bytes($length)
+            {
+                throw new Exception(
+                    'There is no suitable CSPRNG installed on your system'
+                );
+            }
+        }
+    }
+
+    if (!function_exists('random_int')) {
+        require_once $RandomCompatDIR.'/random_int.php';
+    }
+
+    $RandomCompatDIR = null;
+}