<?php
/***************************************************************************
 *                                sessions.php
 *                            -------------------
 *   begin                : Saturday, Feb 13, 2001
 *   copyright            : (C) 2001 The phpBB Group
 *   email                : support@phpbb.com
 *
 *   $Id: sessions.php,v 1.58.2.25 2006/05/18 19:23:07 grahamje Exp $
 *
 *
 ***************************************************************************/

/***************************************************************************
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 ***************************************************************************/

//
// Adds/updates a new session to the database for the given userid.
// Returns the new session ID on success.
//
function session_begin($user_id, $user_ip, $page_id, $auto_create = 0, $enable_autologin = 0, $admin = 0)
{
        global $db, $board_config;
        global $HTTP_COOKIE_VARS, $HTTP_GET_VARS, $SID;

        $cookiename = $board_config['cookie_name'];
        $cookiepath = $board_config['cookie_path'];
        $cookiedomain = $board_config['cookie_domain'];
        $cookiesecure = $board_config['cookie_secure'];

        if ( isset($HTTP_COOKIE_VARS[$cookiename . '_sid']) || isset($HTTP_COOKIE_VARS[$cookiename . '_data']) )
        {
                $session_id = isset($HTTP_COOKIE_VARS[$cookiename . '_sid']) ? $HTTP_COOKIE_VARS[$cookiename . '_sid'] : '';
                $sessiondata = isset($HTTP_COOKIE_VARS[$cookiename . '_data']) ? unserialize(stripslashes($HTTP_COOKIE_VARS[$cookiename . '_data'])) : array();
                $sessionmethod = SESSION_METHOD_COOKIE;
        }
        else
        {
                $sessiondata = array();
                $session_id = ( isset($HTTP_GET_VARS['sid']) ) ? $HTTP_GET_VARS['sid'] : '';
                $sessionmethod = SESSION_METHOD_GET;
        }

        //
        if (!preg_match('/^[A-Za-z0-9]*$/', $session_id)) 
        {
                $session_id = '';
        }

        $page_id = (int) $page_id;

        $last_visit = 0;
        $current_time = time();

        //
        // Are auto-logins allowed?
        // If allow_autologin is not set or is true then they are
        // (same behaviour as old 2.0.x session code)
        //
        if (isset($board_config['allow_autologin']) && !$board_config['allow_autologin'])
        {
                $enable_autologin = $sessiondata['autologinid'] = false;
        }

        // 
        // First off attempt to join with the autologin value if we have one
        // If not, just use the user_id value
        //
        $userdata = array();

        if ($user_id != ANONYMOUS)
        {
                if (isset($sessiondata['autologinid']) && (string) $sessiondata['autologinid'] != '' && $user_id)
                {
                        $sql = 'SELECT u.* 
                                FROM ' . USERS_TABLE . ' u, ' . SESSIONS_KEYS_TABLE . ' k
                                WHERE u.user_id = ' . (int) $user_id . "
                                        AND u.user_active = 1
                                        AND k.user_id = u.user_id
                                        AND k.key_id = '" . md5($sessiondata['autologinid']) . "'";
                        if (!($result = $db->sql_query($sql)))
                        {
                                message_die(CRITICAL_ERROR, 'Error doing DB query userdata row fetch', '', __LINE__, __FILE__, $sql);
                        }

                        $userdata = $db->sql_fetchrow($result);
                        $db->sql_freeresult($result);
                
                        $enable_autologin = $login = 1;
                }
                else if (!$auto_create)
                {
                        $sessiondata['autologinid'] = '';
                        $sessiondata['userid'] = $user_id;

                        $sql = 'SELECT *
                                FROM ' . USERS_TABLE . '
                                WHERE user_id = ' . (int) $user_id . '
                                        AND user_active = 1';
                        if (!($result = $db->sql_query($sql)))
                        {
                                message_die(CRITICAL_ERROR, 'Error doing DB query userdata row fetch', '', __LINE__, __FILE__, $sql);
                        }

                        $userdata = $db->sql_fetchrow($result);
                        $db->sql_freeresult($result);

                        $login = 1;
                }
        }

        //
        // At this point either $userdata should be populated or
        // one of the below is true
        // * Key didn't match one in the DB
        // * User does not exist
        // * User is inactive
        //
        if (!sizeof($userdata) || !is_array($userdata) || !$userdata)
        {
                $sessiondata['autologinid'] = '';
                $sessiondata['userid'] = $user_id = ANONYMOUS;
                $enable_autologin = $login = 0;

                $sql = 'SELECT *
                        FROM ' . USERS_TABLE . '
                        WHERE user_id = ' . (int) $user_id;
                if (!($result = $db->sql_query($sql)))
                {
                        message_die(CRITICAL_ERROR, 'Error doing DB query userdata row fetch', '', __LINE__, __FILE__, $sql);
                }

                $userdata = $db->sql_fetchrow($result);
                $db->sql_freeresult($result);
        }


        //
        // Initial ban check against user id, IP and email address
        //
        preg_match('/(..)(..)(..)(..)/', $user_ip, $user_ip_parts);

        $sql = "SELECT ban_ip, ban_userid, ban_email 
                FROM " . BANLIST_TABLE . " 
                WHERE ban_ip IN ('" . $user_ip_parts[1] . $user_ip_parts[2] . $user_ip_parts[3] . $user_ip_parts[4] . "', '" . $user_ip_parts[1] . $user_ip_parts[2] . $user_ip_parts[3] . "ff', '" . $user_ip_parts[1] . $user_ip_parts[2] . "ffff', '" . $user_ip_parts[1] . "ffffff')
                        OR ban_userid = $user_id";
        if ( $user_id != ANONYMOUS )
        {
                $sql .= " OR ban_email LIKE '" . str_replace("\'", "''", $userdata['user_email']) . "' 
                        OR ban_email LIKE '" . substr(str_replace("\'", "''", $userdata['user_email']), strpos(str_replace("\'", "''", $userdata['user_email']), "@")) . "'";
        }
        if ( !($result = $db->sql_query($sql)) )
        {
                message_die(CRITICAL_ERROR, 'Could not obtain ban information', '', __LINE__, __FILE__, $sql);
        }

        if ( $ban_info = $db->sql_fetchrow($result) )
        {
                if ( $ban_info['ban_ip'] || $ban_info['ban_userid'] || $ban_info['ban_email'] )
                {
                        message_die(CRITICAL_MESSAGE, 'You_been_banned');
                }
        }

        //
        // Create or update the session
        //
        $sql = "UPDATE " . SESSIONS_TABLE . "
                SET session_user_id = $user_id, session_start = $current_time, session_time = $current_time, session_page = $page_id, session_logged_in = $login, session_admin = $admin
                WHERE session_id = '" . $session_id . "' 
                        AND session_ip = '$user_ip'";
        if ( !$db->sql_query($sql) || !$db->sql_affectedrows() )
        {
                $session_id = md5(dss_rand());

                $sql = "INSERT INTO " . SESSIONS_TABLE . "
                        (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin)
                        VALUES ('$session_id', $user_id, $current_time, $current_time, '$user_ip', $page_id, $login, $admin)";
                if ( !$db->sql_query($sql) )
                {
                        message_die(CRITICAL_ERROR, 'Error creating new session', '', __LINE__, __FILE__, $sql);
                }
        }

        if ( $user_id != ANONYMOUS )
        {
                $last_visit = ( $userdata['user_session_time'] > 0 ) ? $userdata['user_session_time'] : $current_time; 

                if (!$admin)
                {
                        $sql = "UPDATE " . USERS_TABLE . " 
                                SET user_session_time = $current_time, user_session_page = $page_id, user_lastvisit = $last_visit
                                WHERE user_id = $user_id";
                        if ( !$db->sql_query($sql) )
                        {
                                message_die(CRITICAL_ERROR, 'Error updating last visit time', '', __LINE__, __FILE__, $sql);
                        }
                }

                $userdata['user_lastvisit'] = $last_visit;

                //
                // Regenerate the auto-login key
                //
                if ($enable_autologin)
                {
                        $auto_login_key = dss_rand() . dss_rand();
                        
                        if (isset($sessiondata['autologinid']) && (string) $sessiondata['autologinid'] != '')
                        {
                                $sql = 'UPDATE ' . SESSIONS_KEYS_TABLE . "
                                        SET last_ip = '$user_ip', key_id = '" . md5($auto_login_key) . "', last_login = $current_time
                                        WHERE key_id = '" . md5($sessiondata['autologinid']) . "'";
                        }
                        else
                        {
                                $sql = 'INSERT INTO ' . SESSIONS_KEYS_TABLE . "(key_id, user_id, last_ip, last_login)
                                        VALUES ('" . md5($auto_login_key) . "', $user_id, '$user_ip', $current_time)";
                        }

                        if ( !$db->sql_query($sql) )
                        {
                                message_die(CRITICAL_ERROR, 'Error updating session key', '', __LINE__, __FILE__, $sql);
                        }
                        
                        $sessiondata['autologinid'] = $auto_login_key;
                        unset($auto_login_key);
                }
                else
                {
                        $sessiondata['autologinid'] = '';
                }

//              $sessiondata['autologinid'] = (!$admin) ? (( $enable_autologin && $sessionmethod == SESSION_METHOD_COOKIE ) ? $auto_login_key : '') : $sessiondata['autologinid'];
                $sessiondata['userid'] = $user_id;
        }

        $userdata['session_id'] = $session_id;
        $userdata['session_ip'] = $user_ip;
        $userdata['session_user_id'] = $user_id;
        $userdata['session_logged_in'] = $login;
        $userdata['session_page'] = $page_id;
        $userdata['session_start'] = $current_time;
        $userdata['session_time'] = $current_time;
        $userdata['session_admin'] = $admin;
        $userdata['session_key'] = $sessiondata['autologinid'];

        setcookie($cookiename . '_data', serialize($sessiondata), $current_time + 31536000, $cookiepath, $cookiedomain, $cookiesecure);
        setcookie($cookiename . '_sid', $session_id, 0, $cookiepath, $cookiedomain, $cookiesecure);

        $SID = 'sid=' . $session_id;

        return $userdata;
}

//
// Checks for a given user session, tidies session table and updates user
// sessions at each page refresh
//
function session_pagestart($user_ip, $thispage_id)
{
        global $db, $lang, $board_config;
        global $HTTP_COOKIE_VARS, $HTTP_GET_VARS, $SID;

        $cookiename = $board_config['cookie_name'];
        $cookiepath = $board_config['cookie_path'];
        $cookiedomain = $board_config['cookie_domain'];
        $cookiesecure = $board_config['cookie_secure'];

        $current_time = time();
        unset($userdata);

        if ( isset($HTTP_COOKIE_VARS[$cookiename . '_sid']) || isset($HTTP_COOKIE_VARS[$cookiename . '_data']) )
        {
                $sessiondata = isset( $HTTP_COOKIE_VARS[$cookiename . '_data'] ) ? unserialize(stripslashes($HTTP_COOKIE_VARS[$cookiename . '_data'])) : array();
                $session_id = isset( $HTTP_COOKIE_VARS[$cookiename . '_sid'] ) ? $HTTP_COOKIE_VARS[$cookiename . '_sid'] : '';
                $sessionmethod = SESSION_METHOD_COOKIE;
        }
        else
        {
                $sessiondata = array();
                $session_id = ( isset($HTTP_GET_VARS['sid']) ) ? $HTTP_GET_VARS['sid'] : '';
                $sessionmethod = SESSION_METHOD_GET;
        }

        // 
        if (!preg_match('/^[A-Za-z0-9]*$/', $session_id))
        {
                $session_id = '';
        }

        $thispage_id = (int) $thispage_id;

        //
        // Does a session exist?
        //
        if ( !empty($session_id) )
        {
                //
                // session_id exists so go ahead and attempt to grab all
                // data in preparation
                //
                $sql = "SELECT u.*, s.*
                        FROM " . SESSIONS_TABLE . " s, " . USERS_TABLE . " u
                        WHERE s.session_id = '$session_id'
                                AND u.user_id = s.session_user_id";
                if ( !($result = $db->sql_query($sql)) )
                {
                        message_die(CRITICAL_ERROR, 'Error doing DB query userdata row fetch', '', __LINE__, __FILE__, $sql);
                }

                $userdata = $db->sql_fetchrow($result);

                //
                // Did the session exist in the DB?
                //
                if ( isset($userdata['user_id']) )
                {
                        //
                        // Do not check IP assuming equivalence, if IPv4 we'll check only first 24
                        // bits ... I've been told (by vHiker) this should alleviate problems with 
                        // load balanced et al proxies while retaining some reliance on IP security.
                        //
                        $ip_check_s = substr($userdata['session_ip'], 0, 6);
                        $ip_check_u = substr($user_ip, 0, 6);

                        if ($ip_check_s == $ip_check_u)
                        {
                                $SID = ($sessionmethod == SESSION_METHOD_GET || defined('IN_ADMIN')) ? 'sid=' . $session_id : '';

                                //
                                // Only update session DB a minute or so after last update
                                //
                                if ( $current_time - $userdata['session_time'] > 60 )
                                {
                                        // A little trick to reset session_admin on session re-usage
                                        $update_admin = (!defined('IN_ADMIN') && $current_time - $userdata['session_time'] > ($board_config['session_length']+60)) ? ', session_admin = 0' : '';

                                        $sql = "UPDATE " . SESSIONS_TABLE . " 
                                                SET session_time = $current_time, session_page = $thispage_id$update_admin
                                                WHERE session_id = '" . $userdata['session_id'] . "'";
                                        if ( !$db->sql_query($sql) )
                                        {
                                                message_die(CRITICAL_ERROR, 'Error updating sessions table', '', __LINE__, __FILE__, $sql);
                                        }

                                        if ( $userdata['user_id'] != ANONYMOUS )
                                        {
                                                $sql = "UPDATE " . USERS_TABLE . " 
                                                        SET user_session_time = $current_time, user_session_page = $thispage_id
                                                        WHERE user_id = " . $userdata['user_id'];
                                                if ( !$db->sql_query($sql) )
                                                {
                                                        message_die(CRITICAL_ERROR, 'Error updating sessions table', '', __LINE__, __FILE__, $sql);
                                                }
                                        }

                                        session_clean($userdata['session_id']);

                                        setcookie($cookiename . '_data', serialize($sessiondata), $current_time + 31536000, $cookiepath, $cookiedomain, $cookiesecure);
                                        setcookie($cookiename . '_sid', $session_id, 0, $cookiepath, $cookiedomain, $cookiesecure);
                                }

                                // Add the session_key to the userdata array if it is set
                                if ( isset($sessiondata['autologinid']) && $sessiondata['autologinid'] != '' )
                                {
                                        $userdata['session_key'] = $sessiondata['autologinid'];
                                }

                                return $userdata;
                        }
                }
        }

        //
        // If we reach here then no (valid) session exists. So we'll create a new one,
        // using the cookie user_id if available to pull basic user prefs.
        //
        $user_id = ( isset($sessiondata['userid']) ) ? intval($sessiondata['userid']) : ANONYMOUS;

        if ( !($userdata = session_begin($user_id, $user_ip, $thispage_id, TRUE)) )
        {
                message_die(CRITICAL_ERROR, 'Error creating user session', '', __LINE__, __FILE__, $sql);
        }

        return $userdata;

}

/**
* Terminates the specified session
* It will delete the entry in the sessions table for this session,
* remove the corresponding auto-login key and reset the cookies
*/
function session_end($session_id, $user_id)
{
        global $db, $lang, $board_config, $userdata;
        global $HTTP_COOKIE_VARS, $HTTP_GET_VARS, $SID;

        $cookiename = $board_config['cookie_name'];
        $cookiepath = $board_config['cookie_path'];
        $cookiedomain = $board_config['cookie_domain'];
        $cookiesecure = $board_config['cookie_secure'];

        $current_time = time();

        if (!preg_match('/^[A-Za-z0-9]*$/', $session_id))
        {
                return;
        }
        
        //
        // Delete existing session
        //
        $sql = 'DELETE FROM ' . SESSIONS_TABLE . " 
                WHERE session_id = '$session_id' 
                        AND session_user_id = $user_id";
        if ( !$db->sql_query($sql) )
        {
                message_die(CRITICAL_ERROR, 'Error removing user session', '', __LINE__, __FILE__, $sql);
        }

        //
        // Remove this auto-login entry (if applicable)
        //
        if ( isset($userdata['session_key']) && $userdata['session_key'] != '' )
        {
                $autologin_key = md5($userdata['session_key']);
                $sql = 'DELETE FROM ' . SESSIONS_KEYS_TABLE . '
                        WHERE user_id = ' . (int) $user_id . "
                                AND key_id = '$autologin_key'";
                if ( !$db->sql_query($sql) )
                {
                        message_die(CRITICAL_ERROR, 'Error removing auto-login key', '', __LINE__, __FILE__, $sql);
                }
        }

        //
        // We expect that message_die will be called after this function,
        // but just in case it isn't, reset $userdata to the details for a guest
        //
        $sql = 'SELECT *
                FROM ' . USERS_TABLE . '
                WHERE user_id = ' . ANONYMOUS;
        if ( !($result = $db->sql_query($sql)) )
        {
                message_die(CRITICAL_ERROR, 'Error obtaining user details', '', __LINE__, __FILE__, $sql);
        }
        if ( !($userdata = $db->sql_fetchrow($result)) )
        {
                message_die(CRITICAL_ERROR, 'Error obtaining user details', '', __LINE__, __FILE__, $sql);
        }
        $db->sql_freeresult($result);


        setcookie($cookiename . '_data', '', $current_time - 31536000, $cookiepath, $cookiedomain, $cookiesecure);
        setcookie($cookiename . '_sid', '', $current_time - 31536000, $cookiepath, $cookiedomain, $cookiesecure);

        return true;
}

/**
* Removes expired sessions and auto-login keys from the database
*/
function session_clean($session_id)
{
        global $board_config, $db;

        //
        // Delete expired sessions
        //
        $sql = 'DELETE FROM ' . SESSIONS_TABLE . ' 
                WHERE session_time < ' . (time() - (int) $board_config['session_length']) . " 
                        AND session_id <> '$session_id'";
        if ( !$db->sql_query($sql) )
        {
                message_die(CRITICAL_ERROR, 'Error clearing sessions table', '', __LINE__, __FILE__, $sql);
        }

        //
        // Delete expired auto-login keys
        // If max_autologin_time is not set then keys will never be deleted
        // (same behaviour as old 2.0.x session code)
        //
        if (!empty($board_config['max_autologin_time']) && $board_config['max_autologin_time'] > 0)
        {
                $sql = 'DELETE FROM ' . SESSIONS_KEYS_TABLE . '
                        WHERE last_login < ' . (time() - (86400 * (int) $board_config['max_autologin_time']));
                $db->sql_query($sql);
        }

        return true;
}

/**
* Reset all login keys for the specified user
* Called on password changes
*/
function session_reset_keys($user_id, $user_ip)
{
        global $db, $userdata, $board_config;

        $key_sql = ($user_id == $userdata['user_id'] && !empty($userdata['session_key'])) ? "AND key_id != '" . md5($userdata['session_key']) . "'" : '';

        $sql = 'DELETE FROM ' . SESSIONS_KEYS_TABLE . '
                WHERE user_id = ' . (int) $user_id . "
                        $key_sql";

        if ( !$db->sql_query($sql) )
        {
                message_die(CRITICAL_ERROR, 'Error removing auto-login keys', '', __LINE__, __FILE__, $sql);
        }

        $where_sql = 'session_user_id = ' . (int) $user_id;
        $where_sql .= ($user_id == $userdata['user_id']) ? " AND session_id <> '" . $userdata['session_id'] . "'" : '';
        $sql = 'DELETE FROM ' . SESSIONS_TABLE . "
                WHERE $where_sql";
        if ( !$db->sql_query($sql) )
        {
                message_die(CRITICAL_ERROR, 'Error removing user session(s)', '', __LINE__, __FILE__, $sql);
        }

        if ( !empty($key_sql) )
        {
                $auto_login_key = dss_rand() . dss_rand();

                $current_time = time();
                
                $sql = 'UPDATE ' . SESSIONS_KEYS_TABLE . "
                        SET last_ip = '$user_ip', key_id = '" . md5($auto_login_key) . "', last_login = $current_time
                        WHERE key_id = '" . md5($userdata['session_key']) . "'";
                
                if ( !$db->sql_query($sql) )
                {
                        message_die(CRITICAL_ERROR, 'Error updating session key', '', __LINE__, __FILE__, $sql);
                }

                // And now rebuild the cookie
                $sessiondata['userid'] = $user_id;
                $sessiondata['autologinid'] = $auto_login_key;
                $cookiename = $board_config['cookie_name'];
                $cookiepath = $board_config['cookie_path'];
                $cookiedomain = $board_config['cookie_domain'];
                $cookiesecure = $board_config['cookie_secure'];

                setcookie($cookiename . '_data', serialize($sessiondata), $current_time + 31536000, $cookiepath, $cookiedomain, $cookiesecure);
                
                $userdata['session_key'] = $auto_login_key;
                unset($sessiondata);
                unset($auto_login_key);
        }
}

//
// Append $SID to a url. Borrowed from phplib and modified. This is an
// extra routine utilised by the session code above and acts as a wrapper
// around every single URL and form action. If you replace the session
// code you must include this routine, even if it's empty.
//
function append_sid($url, $non_html_amp = false)
{
        global $SID;

        if ( !empty($SID) && !preg_match('#sid=#', $url) )
        {
                $url .= ( ( strpos($url, '?') !== false ) ?  ( ( $non_html_amp ) ? '&' : '&amp;' ) : '?' ) . $SID;
        }

        return $url;
}

?>