diff options
Diffstat (limited to 'system/helpers/captcha_helper.php')
| -rw-r--r-- | system/helpers/captcha_helper.php | 107 |
1 files changed, 98 insertions, 9 deletions
diff --git a/system/helpers/captcha_helper.php b/system/helpers/captcha_helper.php index 201987ac8..f98d8a4cd 100644 --- a/system/helpers/captcha_helper.php +++ b/system/helpers/captcha_helper.php @@ -6,7 +6,7 @@ * * This content is released under the MIT License (MIT) * - * Copyright (c) 2014 - 2015, British Columbia Institute of Technology + * Copyright (c) 2014 - 2017, British Columbia Institute of Technology * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal @@ -28,10 +28,10 @@ * * @package CodeIgniter * @author EllisLab Dev Team - * @copyright Copyright (c) 2008 - 2014, EllisLab, Inc. (http://ellislab.com/) - * @copyright Copyright (c) 2014 - 2015, British Columbia Institute of Technology (http://bcit.ca/) + * @copyright Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/) + * @copyright Copyright (c) 2014 - 2017, British Columbia Institute of Technology (http://bcit.ca/) * @license http://opensource.org/licenses/MIT MIT License - * @link http://codeigniter.com + * @link https://codeigniter.com * @since Version 1.0.0 * @filesource */ @@ -44,7 +44,7 @@ defined('BASEPATH') OR exit('No direct script access allowed'); * @subpackage Helpers * @category Helpers * @author EllisLab Dev Team - * @link http://codeigniter.com/user_guide/helpers/captcha_helper.html + * @link https://codeigniter.com/user_guide/helpers/captcha_helper.html */ // ------------------------------------------------------------------------ @@ -68,6 +68,7 @@ if ( ! function_exists('create_captcha')) 'img_url' => '', 'img_width' => '150', 'img_height' => '30', + 'img_alt' => 'captcha', 'font_path' => '', 'expiration' => 7200, 'word_length' => 8, @@ -110,7 +111,8 @@ if ( ! function_exists('create_captcha')) $current_dir = @opendir($img_path); while ($filename = @readdir($current_dir)) { - if (substr($filename, -4) === '.jpg' && (str_replace('.jpg', '', $filename) + $expiration) < $now) + if (in_array(substr($filename, -4), array('.jpg', '.png')) + && (str_replace(array('.jpg', '.png'), '', $filename) + $expiration) < $now) { @unlink($img_path.$filename); } @@ -125,9 +127,96 @@ if ( ! function_exists('create_captcha')) if (empty($word)) { $word = ''; - for ($i = 0, $mt_rand_max = strlen($pool) - 1; $i < $word_length; $i++) + $pool_length = strlen($pool); + $rand_max = $pool_length - 1; + + // PHP7 or a suitable polyfill + if (function_exists('random_int')) + { + try + { + for ($i = 0; $i < $word_length; $i++) + { + $word .= $pool[random_int(0, $rand_max)]; + } + } + catch (Exception $e) + { + // This means fallback to the next possible + // alternative to random_int() + $word = ''; + } + } + } + + if (empty($word)) + { + // Nobody will have a larger character pool than + // 256 characters, but let's handle it just in case ... + // + // No, I do not care that the fallback to mt_rand() can + // handle it; if you trigger this, you're very obviously + // trying to break it. -- Narf + if ($pool_length > 256) + { + return FALSE; + } + + // We'll try using the operating system's PRNG first, + // which we can access through CI_Security::get_random_bytes() + $security = get_instance()->security; + + // To avoid numerous get_random_bytes() calls, we'll + // just try fetching as much bytes as we need at once. + if (($bytes = $security->get_random_bytes($pool_length)) !== FALSE) + { + $byte_index = $word_index = 0; + while ($word_index < $word_length) + { + // Do we have more random data to use? + // It could be exhausted by previous iterations + // ignoring bytes higher than $rand_max. + if ($byte_index === $pool_length) + { + // No failures should be possible if the + // first get_random_bytes() call didn't + // return FALSE, but still ... + for ($i = 0; $i < 5; $i++) + { + if (($bytes = $security->get_random_bytes($pool_length)) === FALSE) + { + continue; + } + + $byte_index = 0; + break; + } + + if ($bytes === FALSE) + { + // Sadly, this means fallback to mt_rand() + $word = ''; + break; + } + } + + list(, $rand_index) = unpack('C', $bytes[$byte_index++]); + if ($rand_index > $rand_max) + { + continue; + } + + $word .= $pool[$rand_index]; + $word_index++; + } + } + } + + if (empty($word)) + { + for ($i = 0; $i < $word_length; $i++) { - $word .= $pool[mt_rand(0, $mt_rand_max)]; + $word .= $pool[mt_rand(0, $rand_max)]; } } elseif ( ! is_string($word)) @@ -245,7 +334,7 @@ if ( ! function_exists('create_captcha')) return FALSE; } - $img = '<img '.($img_id === '' ? '' : 'id="'.$img_id.'"').' src="'.$img_url.$img_filename.'" style="width: '.$img_width.'; height: '.$img_height .'; border: 0;" alt=" " />'; + $img = '<img '.($img_id === '' ? '' : 'id="'.$img_id.'"').' src="'.$img_url.$img_filename.'" style="width: '.$img_width.'; height: '.$img_height .'; border: 0;" alt="'.$img_alt.'" />'; ImageDestroy($im); return array('word' => $word, 'time' => $now, 'image' => $img, 'filename' => $img_filename); |