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Diffstat (limited to 'start.php')
-rw-r--r-- | start.php | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/start.php b/start.php new file mode 100644 index 000000000..f451ffcc6 --- /dev/null +++ b/start.php @@ -0,0 +1,101 @@ +<?php +/** + * Elgg captcha plugin + * + * @package ElggCaptcha + */ + + +register_elgg_event_handler('init','system','captcha_init'); + +function captcha_init() { + + // Register page handler for captcha functionality + elgg_register_page_handler('captcha', 'captcha_page_handler'); + + // Extend CSS + elgg_extend_view('css', 'captcha/css'); + + // Number of background images + elgg_set_config('captcha_num_bg', 5); + + // Default length + elgg_set_config('captcha_length', 5); + + elgg_register_plugin_hook_handler('register', 'user', 'captcha_verify_action_hook'); + elgg_register_plugin_hook_handler('action', 'user/requestnewpassword', 'captcha_verify_action_hook'); +} + +function captcha_page_handler($page) { + + if (isset($page[0])) { + set_input('captcha_token', $page[0]); + } + + include(elgg_get_plugins_path() . "captcha/captcha.php"); +} + +/** + * Generate a token to act as a seed value for the captcha algorithm. + */ +function captcha_generate_token() { + return md5(generate_action_token(time()).rand()); // Use action token plus some random for uniqueness +} + +/** + * Generate a captcha based on the given seed value and length. + * + * @param string $seed_token + * @return string + */ +function captcha_generate_captcha($seed_token) { + /* + * We generate a token out of the random seed value + some session data, + * this means that solving via pr0n site or indian cube farm becomes + * significantly more tricky (we hope). + * + * We also add the site secret, which is unavailable to the client and so should + * make it very very hard to guess values before hand. + * + */ + + return strtolower(substr(md5(generate_action_token(0) . $seed_token), 0, elgg_get_config('captcha_length'))); +} + +/** + * Verify a captcha based on the input value entered by the user and the seed token passed. + * + * @param string $input_value + * @param string $seed_token + * @return bool + */ +function captcha_verify_captcha($input_value, $seed_token) { + if (strcasecmp($input_value, captcha_generate_captcha($seed_token)) == 0) { + return true; + } + return false; +} + +/** + * Listen to the action plugin hook and check the captcha. + * + * @param unknown_type $hook + * @param unknown_type $entity_type + * @param unknown_type $returnvalue + * @param unknown_type $params + */ +function captcha_verify_action_hook($hook, $entity_type, $returnvalue, $params) { + $token = get_input('captcha_token'); + $input = get_input('captcha_input'); + + if (($token) && (captcha_verify_captcha($input, $token))) { + return true; + } + + register_error(elgg_echo('captcha:captchafail')); + + // forward to referrer or else action code sends to front page + forward(REFERER); + + return false; +} |