<?php
/**
* ZeroBin
*
* a zero-knowledge paste bin
*
* @link http://sebsauvage.net/wiki/doku.php?id=php:zerobin
* @copyright 2012 Sébastien SAUVAGE (sebsauvage.net)
* @license http://www.opensource.org/licenses/zlib-license.php The zlib/libpng License
* @version 0.15
*/
/**
* zerobin
*
* Controller, puts it all together.
*/
class zerobin
{
/*
* @const string version
*/
const VERSION = 'Alpha 0.15';
/**
* @access private
* @var array
*/
private $_conf = array(
'model' => 'zerobin_data',
);
/**
* @access private
* @var string
*/
private $_data = '';
/**
* @access private
* @var string
*/
private $_error = '';
/**
* @access private
* @var zerobin_data
*/
private $_model;
/**
* constructor
*
* initializes and runs ZeroBin
*
* @access public
*/
public function __construct()
{
if (version_compare(PHP_VERSION, '5.2.6') < 0)
die('ZeroBin requires php 5.2.6 or above to work. Sorry.');
// In case stupid admin has left magic_quotes enabled in php.ini.
if (get_magic_quotes_gpc())
{
$_POST = array_map('filter::stripslashes_deep', $_POST);
$_GET = array_map('filter::stripslashes_deep', $_GET);
$_COOKIE = array_map('filter::stripslashes_deep', $_COOKIE);
}
// Load config from ini file.
$this->_init();
// Create new paste or comment.
if (!empty($_POST['data']))
{
$this->_create();
}
// Display an existing paste.
elseif (!empty($_SERVER['QUERY_STRING']))
{
$this->_read();
}
// Display ZeroBin frontend
$this->_view();
}
/**
* initialize zerobin
*
* @access private
* @return void
*/
private function _init()
{
foreach (array('cfg', 'lib') as $dir)
{
if (!is_file(PATH . $dir . '/.htaccess')) file_put_contents(
PATH . $dir . '/.htaccess',
'Allow from none' . PHP_EOL .
'Deny from all'. PHP_EOL
);
}
$this->_conf = parse_ini_file(PATH . 'cfg/conf.ini');
$this->_model = $this->_conf['model'];
}
/**
* get the model, create one if needed
*
* @access private
* @return zerobin_data
*/
private function _model()
{
// if needed, initialize the model
if(is_string($this->_model)) {
$this->_model = forward_static_call(array($this->_model, 'getInstance'), $this->_conf['model_options']);
}
return $this->_model;
}
/**
* Store new paste or comment.
*
* POST contains:
* data (mandatory) = json encoded SJCL encrypted text (containing keys: iv,salt,ct)
*
* All optional data will go to meta information:
* expire (optional) = expiration delay (never,10min,1hour,1day,1month,1year,burn) (default:never)
* opendiscusssion (optional) = is the discussion allowed on this paste ? (0/1) (default:0)
* nickname (optional) = in discussion, encoded SJCL encrypted text nickname of author of comment (containing keys: iv,salt,ct)
* parentid (optional) = in discussion, which comment this comment replies to.
* pasteid (optional) = in discussion, which paste this comment belongs to.
*
* @access private
* @return void
*/
private function _create()
{
header('Content-type: application/json');
$error = false;
// Make sure last paste from the IP address was more than 10 seconds ago.
trafficlimiter::setLimit($this->_conf['traffic_limit']);
trafficlimiter::setPath($this->_conf['traffic_dir']);
if (
!trafficlimiter::canPass($_SERVER['REMOTE_ADDR'])
) $this->_return_message(1, 'Please wait 10 seconds between each post.');
// Make sure content is not too big.
$data = $_POST['data'];
if (
strlen($data) > 2000000
) $this->_return_message(1, 'Paste is limited to 2 MB of encrypted data.');
// Make sure format is correct.
if (!sjcl::isValid($data)) $this->_return_message(1, 'Invalid data.');
// Read additional meta-information.
$meta=array();
// Read expiration date
if (!empty($_POST['expire']))
{
switch ($_POST['expire'])
{
case '10min':
$meta['expire_date'] = time()+10*60;
break;
case '1hour':
$meta['expire_date'] = time()+60*60;
break;
case '1day':
$meta['expire_date'] = time()+24*60*60;
break;
case '1month':
$meta['expire_date'] = strtotime('+1 month');
break;
case '1year':
$meta['expire_date'] = strtotime('+1 year');
break;
case 'burn':
$meta['burnafterreading'] = true;
}
}
// Read open discussion flag.
if (!empty($_POST['opendiscussion']))
{
$opendiscussion = $_POST['opendiscussion'];
if ($opendiscussion != 0)
{
if ($opendiscussion != 1) $error = true;
$meta['opendiscussion'] = true;
}
}
// You can't have an open discussion on a "Burn after reading" paste:
if (isset($meta['burnafterreading'])) unset($meta['opendiscussion']);
// Optional nickname for comments
if (!empty($_POST['nickname']))
{
// Generation of the anonymous avatar (Vizhash):
// If a nickname is provided, we generate a Vizhash.
// (We assume that if the user did not enter a nickname, he/she wants
// to be anonymous and we will not generate the vizhash.)
$nick = $_POST['nickname'];
if (!sjcl::isValid($nick))
{
$error = true;
}
else
{
$meta['nickname'] = $nick;
$vz = new vizhash16x16();
$pngdata = $vz->generate($_SERVER['REMOTE_ADDR']);
if ($pngdata != '')
{
$meta['vizhash'] = 'data:image/png;base64,' . base64_encode($pngdata);
}
// Once the avatar is generated, we do not keep the IP address, nor its hash.
}
}
if ($error) $this->_return_message(1, 'Invalid data.');
// Add post date to meta.
$meta['postdate'] = time();
// We just want a small hash to avoid collisions:
// Half-MD5 (64 bits) will do the trick
$dataid = substr(hash('md5', $data), 0, 16);
$storage = array('data' => $data);
// Add meta-information only if necessary.
if (count($meta)) $storage['meta'] = $meta;
// The user posts a comment.
if (
!empty($_POST['parentid']) &&
!empty($_POST['pasteid'])
)
{
$pasteid = $_POST['pasteid'];
$parentid = $_POST['parentid'];
if (
!preg_match('/[a-f\d]{16}/', $pasteid) ||
!preg_match('/[a-f\d]{16}/', $parentid)
) $this->_return_message(1, 'Invalid data.');
// Comments do not expire (it's the paste that expires)
unset($storage['expire_date']);
unset($storage['opendiscussion']);
// Make sure paste exists.
if (
!$this->_model()->exists($pasteid)
) $this->_return_message(1, 'Invalid data.');
// Make sure the discussion is opened in this paste.
$paste = $this->_model()->read($pasteid);
if (
!$paste->meta->opendiscussion
) $this->_return_message(1, 'Invalid data.');
// Check for improbable collision.
if (
$this->_model()->existsComment($pasteid, $parentid, $dataid)
) $this->_return_message(1, 'You are unlucky. Try again.');
// New comment
if (
$this->_model()->createComment($pasteid, $parentid, $dataid, $storage) === false
) $this->_return_message(1, 'Error saving comment. Sorry.');
// 0 = no error
$this->_return_message(0, $dataid);
}
// The user posts a standard paste.
else
{
// Check for improbable collision.
if (
$this->_model()->exists($dataid)
) $this->_return_message(1, 'You are unlucky. Try again.');
// New paste
if (
$this->_model()->create($dataid, $storage) === false
) $this->_return_message(1, 'Error saving paste. Sorry.');
// 0 = no error
$this->_return_message(0, $dataid);
}
$this->_return_message(1, 'Server error.');
}
/**
* Read an existing paste or comment.
*
* @access private
* @return void
*/
private function _read()
{
$dataid = $_SERVER['QUERY_STRING'];
// Is this a valid paste identifier?
if (preg_match('/[a-f\d]{16}/', $dataid))
{
// Check that paste exists.
if ($this->_model()->exists($dataid))
{
// Get the paste itself.
$paste = $this->_model()->read($dataid);
// See if paste has expired.
if (
isset($paste->meta->expire_date) &&
$paste->meta->expire_date < time()
)
{
// Delete the paste
$this->_model()->delete($dataid);
$this->_error = 'Paste does not exist or has expired.';
}
// If no error, return the paste.
else
{
// We kindly provide the remaining time before expiration (in seconds)
if (
property_exists($paste->meta, 'expire_date')
) $paste->meta->remaining_time = $paste->meta->expire_date - time();
// The paste itself is the first in the list of encrypted messages.
$messages = array($paste);
// If it's a discussion, get all comments.
if (
property_exists($paste->meta, 'opendiscussion') &&
$paste->meta->opendiscussion
)
{
$messages = array_merge(
$messages,
$this->_model()->readComments($dataid)
);
}
$this->_data = json_encode($messages);
// If the paste was meant to be read only once, delete it.
if (
property_exists($paste->meta, 'burnafterreading') &&
$paste->meta->burnafterreading
) $this->_model()->delete($dataid);
}
}
else
{
$this->_error = 'Paste does not exist or has expired.';
}
}
}
/**
* Display ZeroBin frontend.
*
* @access private
* @return void
*/
private function _view()
{
header('Content-Type: text/html; charset=utf-8');
$page = new RainTPL;
// We escape it here because ENT_NOQUOTES can't be used in RainTPL templates.
$page->assign('CIPHERDATA', htmlspecialchars($this->_data, ENT_NOQUOTES));
$page->assign('ERRORMESSAGE', $this->_error);
$page->assign('VERSION', self::VERSION);
$page->draw('page');
}
/**
* return JSON encoded message and exit
*
* @access private
* @param bool $status
* @param string $message
* @return void
*/
private function _return_message($status, $message)
{
$result = array('status' => $status);
if ($status)
{
$result['message'] = $message;
}
else
{
$result['id'] = $message;
}
exit(json_encode($result));
}
}