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Diffstat (limited to 'engine/lib/actions.php')
| -rw-r--r-- | engine/lib/actions.php | 549 |
1 files changed, 549 insertions, 0 deletions
diff --git a/engine/lib/actions.php b/engine/lib/actions.php new file mode 100644 index 000000000..8047914ac --- /dev/null +++ b/engine/lib/actions.php @@ -0,0 +1,549 @@ +<?php +/** + * Elgg Actions + * + * Actions are one of the primary controllers (The C in MVC) in Elgg. They are + * registered by {@link register_elgg_action()} and are called by URL + * http://elggsite.org/action/action_name. For URLs, a rewrite rule in + * .htaccess passes the action name to engine/handlers/action_handler.php, + * which dispatches the request for the action. + * + * An action name must be registered to a file in the system. Core actions are + * found in /actions/ and plugin actions are usually under /mod/<plugin>/actions/. + * It is recommended that actions be namespaced to avoid collisions. + * + * All actions require security tokens. Using the {@elgg_view input/form} view + * will automatically add tokens as hidden inputs as will the elgg_view_form() + * function. To manually add hidden inputs, use the {@elgg_view input/securitytoken} view. + * + * To include security tokens for actions called via GET, use + * {@link elgg_add_security_tokens_to_url()} or specify is_action as true when + * using {@lgg_view output/url}. + * + * Action tokens can be manually generated by using {@link generate_action_token()}. + * + * @tip When registered, actions can be restricted to logged in or admin users. + * + * @tip Action URLs should be called with a trailing / to prevent 301 redirects. + * + * @package Elgg.Core + * @subpackage Actions + * @link http://docs.elgg.org/Actions + * @link http://docs.elgg.org/Actions/Tokens + */ + +/** + * Perform an action. + * + * This function executes the action with name $action as registered + * by {@link elgg_register_action()}. + * + * The plugin hook 'action', $action_name will be triggered before the action + * is executed. If a handler returns false, it will prevent the action script + * from being called. + * + * @note If an action isn't registered in the system or is registered + * to an unavailable file the user will be forwarded to the site front + * page and an error will be emitted via {@link register_error()}. + * + * @warning All actions require {@link http://docs.elgg.org/Actions/Tokens Action Tokens}. + * + * @param string $action The requested action + * @param string $forwarder Optionally, the location to forward to + * + * @link http://docs.elgg.org/Actions + * @see elgg_register_action() + * + * @return void + * @access private + */ +function action($action, $forwarder = "") { + global $CONFIG; + + $action = rtrim($action, '/'); + + // @todo REMOVE THESE ONCE #1509 IS IN PLACE. + // Allow users to disable plugins without a token in order to + // remove plugins that are incompatible. + // Logout for convenience. + // file/download (see #2010) + $exceptions = array( + 'admin/plugins/disable', + 'logout', + 'file/download', + ); + + if (!in_array($action, $exceptions)) { + action_gatekeeper($action); + } + + $forwarder = str_replace(elgg_get_site_url(), "", $forwarder); + $forwarder = str_replace("http://", "", $forwarder); + $forwarder = str_replace("@", "", $forwarder); + if (substr($forwarder, 0, 1) == "/") { + $forwarder = substr($forwarder, 1); + } + + if (!isset($CONFIG->actions[$action])) { + register_error(elgg_echo('actionundefined', array($action))); + } elseif (!elgg_is_admin_logged_in() && ($CONFIG->actions[$action]['access'] === 'admin')) { + register_error(elgg_echo('actionunauthorized')); + } elseif (!elgg_is_logged_in() && ($CONFIG->actions[$action]['access'] !== 'public')) { + register_error(elgg_echo('actionloggedout')); + } else { + // Returning falsy doesn't produce an error + // We assume this will be handled in the hook itself. + if (elgg_trigger_plugin_hook('action', $action, null, true)) { + if (!include($CONFIG->actions[$action]['file'])) { + register_error(elgg_echo('actionnotfound', array($action))); + } + } + } + + $forwarder = empty($forwarder) ? REFERER : $forwarder; + forward($forwarder); +} + +/** + * Registers an action. + * + * Actions are registered to a script in the system and are executed + * either by the URL http://elggsite.org/action/action_name/. + * + * $filename must be the full path of the file to register, or a path relative + * to the core actions/ dir. + * + * Actions should be namedspaced for your plugin. Example: + * <code> + * elgg_register_action('myplugin/save_settings', ...); + * </code> + * + * @tip Put action files under the actions/<plugin_name> directory of your plugin. + * + * @tip You don't need to include engine/start.php in your action files. + * + * @internal Actions are saved in $CONFIG->actions as an array in the form: + * <code> + * array( + * 'file' => '/location/to/file.php', + * 'access' => 'public', 'logged_in', or 'admin' + * ) + * </code> + * + * @param string $action The name of the action (eg "register", "account/settings/save") + * @param string $filename Optionally, the filename where this action is located. If not specified, + * will assume the action is in elgg/actions/<action>.php + * @param string $access Who is allowed to execute this action: public, logged_in, admin. + * (default: logged_in) + * + * @see action() + * @see http://docs.elgg.org/Actions + * + * @return bool + */ +function elgg_register_action($action, $filename = "", $access = 'logged_in') { + global $CONFIG; + + // plugins are encouraged to call actions with a trailing / to prevent 301 + // redirects but we store the actions without it + $action = rtrim($action, '/'); + + if (!isset($CONFIG->actions)) { + $CONFIG->actions = array(); + } + + if (empty($filename)) { + $path = ""; + if (isset($CONFIG->path)) { + $path = $CONFIG->path; + } + + $filename = $path . "actions/" . $action . ".php"; + } + + $CONFIG->actions[$action] = array( + 'file' => $filename, + 'access' => $access, + ); + return true; +} + +/** + * Unregisters an action + * + * @param string $action Action name + * @return bool + * @since 1.8.1 + */ +function elgg_unregister_action($action) { + global $CONFIG; + + if (isset($CONFIG->actions[$action])) { + unset($CONFIG->actions[$action]); + return true; + } else { + return false; + } +} + +/** + * Is the token timestamp within acceptable range? + * + * @param int $ts timestamp from the CSRF token + * + * @return bool + */ +function _elgg_validate_token_timestamp($ts) { + $action_token_timeout = elgg_get_config('action_token_timeout'); + // default is 2 hours + $timeout = ($action_token_timeout !== null) ? $action_token_timeout : 2; + + $hour = 60 * 60; + $timeout = $timeout * $hour; + $now = time(); + + // Validate time to ensure its not crazy + return ($timeout == 0 || ($ts > $now - $timeout) && ($ts < $now + $timeout)); +} + +/** + * Validate an action token. + * + * Calls to actions will automatically validate tokens. If tokens are not + * present or invalid, the action will be denied and the user will be redirected. + * + * Plugin authors should never have to manually validate action tokens. + * + * @param bool $visibleerrors Emit {@link register_error()} errors on failure? + * @param mixed $token The token to test against. Default: $_REQUEST['__elgg_token'] + * @param mixed $ts The time stamp to test against. Default: $_REQUEST['__elgg_ts'] + * + * @return bool + * @see generate_action_token() + * @link http://docs.elgg.org/Actions/Tokens + * @access private + */ +function validate_action_token($visibleerrors = TRUE, $token = NULL, $ts = NULL) { + if (!$token) { + $token = get_input('__elgg_token'); + } + + if (!$ts) { + $ts = get_input('__elgg_ts'); + } + + $session_id = session_id(); + + if (($token) && ($ts) && ($session_id)) { + // generate token, check with input and forward if invalid + $required_token = generate_action_token($ts); + + // Validate token + if ($token == $required_token) { + + if (_elgg_validate_token_timestamp($ts)) { + // We have already got this far, so unless anything + // else says something to the contrary we assume we're ok + $returnval = true; + + $returnval = elgg_trigger_plugin_hook('action_gatekeeper:permissions:check', 'all', array( + 'token' => $token, + 'time' => $ts + ), $returnval); + + if ($returnval) { + return true; + } else if ($visibleerrors) { + register_error(elgg_echo('actiongatekeeper:pluginprevents')); + } + } else if ($visibleerrors) { + // this is necessary because of #5133 + if (elgg_is_xhr()) { + register_error(elgg_echo('js:security:token_refresh_failed', array(elgg_get_site_url()))); + } else { + register_error(elgg_echo('actiongatekeeper:timeerror')); + } + } + } else if ($visibleerrors) { + // this is necessary because of #5133 + if (elgg_is_xhr()) { + register_error(elgg_echo('js:security:token_refresh_failed', array(elgg_get_site_url()))); + } else { + register_error(elgg_echo('actiongatekeeper:tokeninvalid')); + } + } + } else { + if (! empty($_SERVER['CONTENT_LENGTH']) && empty($_POST)) { + // The size of $_POST or uploaded file has exceed the size limit + $error_msg = elgg_trigger_plugin_hook('action_gatekeeper:upload_exceeded_msg', 'all', array( + 'post_size' => $_SERVER['CONTENT_LENGTH'], + 'visible_errors' => $visibleerrors, + ), elgg_echo('actiongatekeeper:uploadexceeded')); + } else { + $error_msg = elgg_echo('actiongatekeeper:missingfields'); + } + if ($visibleerrors) { + register_error($error_msg); + } + } + + return FALSE; +} + +/** + * Validates the presence of action tokens. + * + * This function is called for all actions. If action tokens are missing, + * the user will be forwarded to the site front page and an error emitted. + * + * This function verifies form input for security features (like a generated token), + * and forwards if they are invalid. + * + * @param string $action The action being performed + * + * @return mixed True if valid or redirects. + * @access private + */ +function action_gatekeeper($action) { + if ($action === 'login') { + if (validate_action_token(false)) { + return true; + } + + $token = get_input('__elgg_token'); + $ts = (int)get_input('__elgg_ts'); + if ($token && _elgg_validate_token_timestamp($ts)) { + // The tokens are present and the time looks valid: this is probably a mismatch due to the + // login form being on a different domain. + register_error(elgg_echo('actiongatekeeper:crosssitelogin')); + + + forward('login', 'csrf'); + } + + // let the validator send an appropriate msg + validate_action_token(); + + } elseif (validate_action_token()) { + return true; + } + + forward(REFERER, 'csrf'); +} + +/** + * Generate an action token. + * + * Action tokens are based on timestamps as returned by {@link time()}. + * They are valid for one hour. + * + * Action tokens should be passed to all actions name __elgg_ts and __elgg_token. + * + * @warning Action tokens are required for all actions. + * + * @param int $timestamp Unix timestamp + * + * @see @elgg_view input/securitytoken + * @see @elgg_view input/form + * @example actions/manual_tokens.php + * + * @return string|false + * @access private + */ +function generate_action_token($timestamp) { + $site_secret = get_site_secret(); + $session_id = session_id(); + // Session token + $st = $_SESSION['__elgg_session']; + + if (($site_secret) && ($session_id)) { + return md5($site_secret . $timestamp . $session_id . $st); + } + + return FALSE; +} + +/** + * Initialise the site secret (32 bytes: "z" to indicate format + 186-bit key in Base64 URL). + * + * Used during installation and saves as a datalist. + * + * Note: Old secrets were hex encoded. + * + * @return mixed The site secret hash or false + * @access private + * @todo Move to better file. + */ +function init_site_secret() { + $secret = 'z' . ElggCrypto::getRandomString(31); + + if (datalist_set('__site_secret__', $secret)) { + return $secret; + } + + return FALSE; +} + +/** + * Returns the site secret. + * + * Used to generate difficult to guess hashes for sessions and action tokens. + * + * @return string Site secret. + * @access private + * @todo Move to better file. + */ +function get_site_secret() { + $secret = datalist_get('__site_secret__'); + if (!$secret) { + $secret = init_site_secret(); + } + + return $secret; +} + +/** + * Get the strength of the site secret + * + * @return string "strong", "moderate", or "weak" + * @access private + */ +function _elgg_get_site_secret_strength() { + $secret = get_site_secret(); + if ($secret[0] !== 'z') { + $rand_max = getrandmax(); + if ($rand_max < pow(2, 16)) { + return 'weak'; + } + if ($rand_max < pow(2, 32)) { + return 'moderate'; + } + } + return 'strong'; +} + +/** + * Check if an action is registered and its script exists. + * + * @param string $action Action name + * + * @return bool + * @since 1.8.0 + */ +function elgg_action_exists($action) { + global $CONFIG; + + return (isset($CONFIG->actions[$action]) && file_exists($CONFIG->actions[$action]['file'])); +} + +/** + * Checks whether the request was requested via ajax + * + * @return bool whether page was requested via ajax + * @since 1.8.0 + */ +function elgg_is_xhr() { + return isset($_SERVER['HTTP_X_REQUESTED_WITH']) + && strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) == 'xmlhttprequest' || + get_input('X-Requested-With') === 'XMLHttpRequest'; +} + +/** + * Catch calls to forward() in ajax request and force an exit. + * + * Forces response is json of the following form: + * <pre> + * { + * "current_url": "the.url.we/were/coming/from", + * "forward_url": "the.url.we/were/going/to", + * "system_messages": { + * "messages": ["msg1", "msg2", ...], + * "errors": ["err1", "err2", ...] + * }, + * "status": -1 //or 0 for success if there are no error messages present + * } + * </pre> + * where "system_messages" is all message registers at the point of forwarding + * + * @param string $hook + * @param string $type + * @param string $reason + * @param array $params + * @return void + * @access private + */ +function ajax_forward_hook($hook, $type, $reason, $params) { + if (elgg_is_xhr()) { + // always pass the full structure to avoid boilerplate JS code. + $params = array( + 'output' => '', + 'status' => 0, + 'system_messages' => array( + 'error' => array(), + 'success' => array() + ) + ); + + //grab any data echo'd in the action + $output = ob_get_clean(); + + //Avoid double-encoding in case data is json + $json = json_decode($output); + if (isset($json)) { + $params['output'] = $json; + } else { + $params['output'] = $output; + } + + //Grab any system messages so we can inject them via ajax too + $system_messages = system_messages(NULL, ""); + + if (isset($system_messages['success'])) { + $params['system_messages']['success'] = $system_messages['success']; + } + + if (isset($system_messages['error'])) { + $params['system_messages']['error'] = $system_messages['error']; + $params['status'] = -1; + } + + // Check the requester can accept JSON responses, if not fall back to + // returning JSON in a plain-text response. Some libraries request + // JSON in an invisible iframe which they then read from the iframe, + // however some browsers will not accept the JSON MIME type. + if (stripos($_SERVER['HTTP_ACCEPT'], 'application/json') === FALSE) { + header("Content-type: text/plain"); + } else { + header("Content-type: application/json"); + } + + echo json_encode($params); + exit; + } +} + +/** + * Buffer all output echo'd directly in the action for inclusion in the returned JSON. + * @return void + * @access private + */ +function ajax_action_hook() { + if (elgg_is_xhr()) { + ob_start(); + } +} + +/** + * Initialize some ajaxy actions features + * @access private + */ +function actions_init() { + elgg_register_action('security/refreshtoken', '', 'public'); + + elgg_register_simplecache_view('js/languages/en'); + + elgg_register_plugin_hook_handler('action', 'all', 'ajax_action_hook'); + elgg_register_plugin_hook_handler('forward', 'all', 'ajax_forward_hook'); +} + +elgg_register_event_handler('init', 'system', 'actions_init'); |