Plugin to restrict too many registrations from one IP

We throttle registrations by IP. We record IP address of each
registration, and if too many registrations have been done by the same
IP address in the time interval, we reject the registration.

plugins/RegisterThrottle/RegisterThrottlePlugin.php

+<?php
+/**
+ * StatusNet - the distributed open-source microblogging tool
+ * Copyright (C) 2010, StatusNet, Inc.
+ *
+ * Throttle registration by IP address
+ *
+ * PHP version 5
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @category  Spam
+ * @package   StatusNet
+ * @author    Evan Prodromou <evan@status.net>
+ * @copyright 2010 StatusNet, Inc.
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
+ * @link      http://status.net/
+ */
+
+if (!defined('STATUSNET')) {
+    exit(1);
+}
+
+/**
+ * Throttle registration by IP address
+ *
+ * We a) record IP address of registrants and b) throttle registrations.
+ *
+ * @category  Spam
+ * @package   StatusNet
+ * @author    Evan Prodromou <evan@status.net>
+ * @copyright 2010 StatusNet, Inc.
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
+ * @link      http://status.net/
+ */
+
+class RegisterThrottlePlugin extends Plugin
+{
+    /**
+     * Array of time spans in seconds to limits.
+     *
+     * Default is 3 registrations per hour, 5 per day, 10 per week.
+     */
+
+    public $regLimits = array(604800 => 10, // per week
+                              86400 => 5, // per day
+                              3600 => 3); // per hour
+
+    /**
+     * Database schema setup
+     *
+     * We store user registrations in a table registration_ip.
+     *
+     * @return boolean hook value; true means continue processing, false means stop.
+     */
+
+    function onCheckSchema()
+    {
+        $schema = Schema::get();
+
+        // For storing user-submitted flags on profiles
+
+        $schema->ensureTable('registration_ip',
+                             array(new ColumnDef('user_id', 'integer', null,
+                                                 false, 'PRI'),
+                                   new ColumnDef('ipaddress', 'varchar', 15, false, 'MUL'),
+                                   new ColumnDef('created', 'timestamp', null, false, 'MUL')));
+
+        return true;
+    }
+
+    /**
+     * Load related modules when needed
+     *
+     * @param string $cls Name of the class to be loaded
+     *
+     * @return boolean hook value; true means continue processing, false means stop.
+     */
+
+    function onAutoload($cls)
+    {
+        $dir = dirname(__FILE__);
+
+        switch ($cls)
+        {
+        case 'Registration_ip':
+            include_once $dir . '/'.$cls.'.php';
+            return false;
+        default:
+            return true;
+        }
+    }
+
+    /**
+     * Called when someone tries to register.
+     *
+     * We check the IP here to determine if it goes over any of our
+     * configured limits.
+     *
+     * @param Action $action Action that is being executed
+     *
+     * @return boolean hook value
+     *
+     */
+
+    function onStartRegistrationTry($action)
+    {
+        $ipaddress = $this->_getIpAddress();
+
+        if (empty($ipaddress)) {
+            throw new ServerException(_m('Cannot find IP address.'));
+        }
+
+        foreach ($this->regLimits as $seconds => $limit) {
+
+            $this->debug("Checking $seconds ($limit)");
+
+            $reg = $this->_getNthReg($ipaddress, $limit);
+
+            if (!empty($reg)) {
+                $this->debug("Got a {$limit}th registration.");
+                $regtime = strtotime($reg->created);
+                $now     = time();
+                $this->debug("Comparing {$regtime} to {$now}");
+                if ($now - $regtime < $seconds) {
+                    throw new Exception(_("Too many registrations. Take a break and try again later."));
+                }
+            }
+        }
+
+        return true;
+    }
+
+    /**
+     * Called after someone registers.
+     *
+     * We record the successful registration and IP address.
+     *
+     * @param Action $action Action that is being executed
+     *
+     * @return boolean hook value
+     *
+     */
+
+    function onEndRegistrationTry($action)
+    {
+        $ipaddress = $this->_getIpAddress();
+
+        if (empty($ipaddress)) {
+            throw new ServerException(_m('Cannot find IP address.'));
+        }
+
+        $user = common_current_user();
+
+        if (empty($user)) {
+            throw new ServerException(_m('Cannot find user after successful registration.'));
+        }
+
+        $reg = new Registration_ip();
+
+        $reg->user_id   = $user->id;
+        $reg->ipaddress = $ipaddress;
+
+        $result = $reg->insert();
+
+        if (!$result) {
+            common_log_db_error($reg, 'INSERT', __FILE__);
+            // @todo throw an exception?
+        }
+
+        return true;
+    }
+
+    /**
+     * Check the version of the plugin.
+     *
+     * @param array &$versions Version array.
+     *
+     * @return boolean hook value
+     */
+
+    function onPluginVersion(&$versions)
+    {
+        $versions[] = array('name' => 'RegisterThrottle',
+                            'version' => STATUSNET_VERSION,
+                            'author' => 'Evan Prodromou',
+                            'homepage' => 'http://status.net/wiki/Plugin:RegisterThrottle',
+                            'description' =>
+                            _m('Throttles excessive registration from a single IP.'));
+        return true;
+    }
+
+    /**
+     * Gets the current IP address.
+     *
+     * @return string IP address or null if not found.
+     */
+
+    private function _getIpAddress()
+    {
+        $keys = array('HTTP_X_FORWARDED_FOR',
+                      'CLIENT-IP',
+                      'REMOTE_ADDR');
+
+        foreach ($keys as $k) {
+            if (!empty($_SERVER[$k])) {
+                return $_SERVER[$k];
+            }
+        }
+
+        return null;
+    }
+
+    /**
+     * Gets the Nth registration with the given IP address.
+     *
+     * @param string  $ipaddress Address to key on
+     * @param integer $n         Nth address
+     *
+     * @return Registration_ip nth registration or null if not found.
+     */
+
+    private function _getNthReg($ipaddress, $n)
+    {
+        $reg = new Registration_ip();
+
+        $reg->ipaddress = $ipaddress;
+
+        $reg->orderBy('created DESC');
+        $reg->limit($n - 1, 1);
+
+        if ($reg->find(true)) {
+            return $reg;
+        } else {
+            return null;
+        }
+    }
+}

plugins/RegisterThrottle/Registration_ip.php

+<?php
+/**
+ * Data class for storing IP addresses of new registrants.
+ *
+ * PHP version 5
+ *
+ * @category Data
+ * @package  StatusNet
+ * @author   Evan Prodromou <evan@status.net>
+ * @license  http://www.fsf.org/licensing/licenses/agpl.html AGPLv3
+ * @link     http://status.net/
+ *
+ * StatusNet - the distributed open-source microblogging tool
+ * Copyright (C) 2010, StatusNet, Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.     See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+if (!defined('STATUSNET')) {
+    exit(1);
+}
+
+require_once INSTALLDIR . '/classes/Memcached_DataObject.php';
+
+/**
+ * Data class for storing IP addresses of new registrants.
+ *
+ * @category Spam
+ * @package  StatusNet
+ * @author   Evan Prodromou <evan@status.net>
+ * @license  http://www.fsf.org/licensing/licenses/agpl.html AGPLv3
+ * @link     http://status.net/
+ */
+
+class Registration_ip extends Memcached_DataObject
+{
+    public $__table = 'registration_ip';     // table name
+    public $user_id;                         // int(4)  primary_key not_null
+    public $ipaddress;                       // varchar(15)
+    public $created;                         // timestamp
+
+    /**
+     * Get an instance by key
+     *
+     * @param string $k Key to use to lookup (usually 'user_id' for this class)
+     * @param mixed  $v Value to lookup
+     *
+     * @return User_greeting_count object found, or null for no hits
+     *
+     */
+
+    function staticGet($k, $v=null)
+    {
+        return Memcached_DataObject::staticGet('Registration_ip', $k, $v);
+    }
+
+    /**
+     * return table definition for DB_DataObject
+     *
+     * @return array array of column definitions
+     */
+
+    function table()
+    {
+        return array('user_id' => DB_DATAOBJECT_INT + DB_DATAOBJECT_NOTNULL,
+                     'ipaddress' => DB_DATAOBJECT_STR + DB_DATAOBJECT_NOTNULL,
+                     'created' => DB_DATAOBJECT_MYSQLTIMESTAMP + DB_DATAOBJECT_NOTNULL);
+    }
+
+    /**
+     * return key definitions for DB_DataObject
+     *
+     * DB_DataObject needs to know about keys that the table has; this function
+     * defines them.
+     *
+     * @return array key definitions
+     */
+
+    function keys()
+    {
+        return array('user_id' => 'K');
+    }
+
+    /**
+     * return key definitions for Memcached_DataObject
+     *
+     * Our caching system uses the same key definitions, but uses a different
+     * method to get them.
+     *
+     * @return array key definitions
+     */
+
+    function keyTypes()
+    {
+        return $this->keys();
+    }
+
+    /**
+     * Magic formula for non-autoincrementing integer primary keys
+     *
+     * If a table has a single integer column as its primary key, DB_DataObject
+     * assumes that the column is auto-incrementing and makes a sequence table
+     * to do this incrementation. Since we don't need this for our class, we
+     * overload this method and return the magic formula that DB_DataObject needs.
+     *
+     * @return array magic three-false array that stops auto-incrementing.
+     */
+
+    function sequenceKey()
+    {
+        return array(false, false, false);
+    }
+}