<?php
/**
* PrivateBin
*
* a zero-knowledge paste bin
*
* @link https://github.com/PrivateBin/PrivateBin
* @copyright 2012 Sébastien SAUVAGE (sebsauvage.net)
* @license https://www.opensource.org/licenses/zlib-license.php The zlib/libpng License
* @version 1.7.1
*/
namespace PrivateBin\Data;
use Exception;
use GlobIterator;
use PrivateBin\Json;
/**
* Filesystem
*
* Model for filesystem data access, implemented as a singleton.
*/
class Filesystem extends AbstractData
{
/**
* glob() pattern of the two folder levels and the paste files under the
* configured path. Needs to return both files with and without .php suffix,
* so they can be hardened by _prependRename(), which is hooked into exists().
*
* > Note that wildcard patterns are not regular expressions, although they
* > are a bit similar.
*
* @link https://man7.org/linux/man-pages/man7/glob.7.html
* @const string
*/
const PASTE_FILE_PATTERN = DIRECTORY_SEPARATOR . '[a-f0-9][a-f0-9]' .
DIRECTORY_SEPARATOR . '[a-f0-9][a-f0-9]' . DIRECTORY_SEPARATOR .
'[a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9]' .
'[a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9]*';
/**
* first line in paste or comment files, to protect their contents from browsing exposed data directories
*
* @const string
*/
const PROTECTION_LINE = '<?php http_response_code(403); /*';
/**
* line in generated .htaccess files, to protect exposed directories from being browsable on apache web servers
*
* @const string
*/
const HTACCESS_LINE = 'Require all denied';
/**
* path in which to persist something
*
* @access private
* @var string
*/
private $_path = 'data';
/**
* instantiates a new Filesystem data backend
*
* @access public
* @param array $options
*/
public function __construct(array $options)
{
// if given update the data directory
if (
is_array($options) &&
array_key_exists('dir', $options)
) {
$this->_path = $options['dir'];
}
}
/**
* Create a paste.
*
* @access public
* @param string $pasteid
* @param array $paste
* @return bool
*/
public function create($pasteid, array $paste)
{
$storagedir = $this->_dataid2path($pasteid);
$file = $storagedir . $pasteid . '.php';
if (is_file($file)) {
return false;
}
if (!is_dir($storagedir)) {
mkdir($storagedir, 0700, true);
}
return $this->_store($file, $paste);
}
/**
* Read a paste.
*
* @access public
* @param string $pasteid
* @return array|false
*/
public function read($pasteid)
{
if (
!$this->exists($pasteid) ||
!$paste = $this->_get($this->_dataid2path($pasteid) . $pasteid . '.php')
) {
return false;
}
return self::upgradePreV1Format($paste);
}
/**
* Delete a paste and its discussion.
*
* @access public
* @param string $pasteid
*/
public function delete($pasteid)
{
$pastedir = $this->_dataid2path($pasteid);
if (is_dir($pastedir)) {
// Delete the paste itself.
if (is_file($pastedir . $pasteid . '.php')) {
unlink($pastedir . $pasteid . '.php');
}
// Delete discussion if it exists.
$discdir = $this->_dataid2discussionpath($pasteid);
if (is_dir($discdir)) {
// Delete all files in discussion directory
$dir = dir($discdir);
while (false !== ($filename = $dir->read())) {
if (is_file($discdir . $filename)) {
unlink($discdir . $filename);
}
}
$dir->close();
rmdir($discdir);
}
}
}
/**
* Test if a paste exists.
*
* @access public
* @param string $pasteid
* @return bool
*/
public function exists($pasteid)
{
$basePath = $this->_dataid2path($pasteid) . $pasteid;
$pastePath = $basePath . '.php';
// convert to PHP protected files if needed
if (is_readable($basePath)) {
$this->_prependRename($basePath, $pastePath);
// convert comments, too
$discdir = $this->_dataid2discussionpath($pasteid);
if (is_dir($discdir)) {
$dir = dir($discdir);
while (false !== ($filename = $dir->read())) {
if (substr($filename, -4) !== '.php' && strlen($filename) >= 16) {
$commentFilename = $discdir . $filename . '.php';
$this->_prependRename($discdir . $filename, $commentFilename);
}
}
$dir->close();
}
}
return is_readable($pastePath);
}
/**
* Create a comment in a paste.
*
* @access public
* @param string $pasteid
* @param string $parentid
* @param string $commentid
* @param array $comment
* @return bool
*/
public function createComment($pasteid, $parentid, $commentid, array $comment)
{
$storagedir = $this->_dataid2discussionpath($pasteid);
$file = $storagedir . $pasteid . '.' . $commentid . '.' . $parentid . '.php';
if (is_file($file)) {
return false;
}
if (!is_dir($storagedir)) {
mkdir($storagedir, 0700, true);
}
return $this->_store($file, $comment);
}
/**
* Read all comments of paste.
*
* @access public
* @param string $pasteid
* @return array
*/
public function readComments($pasteid)
{
$comments = array();
$discdir = $this->_dataid2discussionpath($pasteid);
if (is_dir($discdir)) {
$dir = dir($discdir);
while (false !== ($filename = $dir->read())) {
// Filename is in the form pasteid.commentid.parentid.php:
// - pasteid is the paste this reply belongs to.
// - commentid is the comment identifier itself.
// - parentid is the comment this comment replies to (It can be pasteid)
if (is_file($discdir . $filename)) {
$comment = $this->_get($discdir . $filename);
$items = explode('.', $filename);
// Add some meta information not contained in file.
$comment['id'] = $items[1];
$comment['parentid'] = $items[2];
// Store in array
$key = $this->getOpenSlot(
$comments,
(int) array_key_exists('created', $comment['meta']) ?
$comment['meta']['created'] : // v2 comments
$comment['meta']['postdate'] // v1 comments
);
$comments[$key] = $comment;
}
}
$dir->close();
// Sort comments by date, oldest first.
ksort($comments);
}
return $comments;
}
/**
* Test if a comment exists.
*
* @access public
* @param string $pasteid
* @param string $parentid
* @param string $commentid
* @return bool
*/
public function existsComment($pasteid, $parentid, $commentid)
{
return is_file(
$this->_dataid2discussionpath($pasteid) .
$pasteid . '.' . $commentid . '.' . $parentid . '.php'
);
}
/**
* Save a value.
*
* @access public
* @param string $value
* @param string $namespace
* @param string $key
* @return bool
*/
public function setValue($value, $namespace, $key = '')
{
switch ($namespace) {
case 'purge_limiter':
return $this->_storeString(
$this->_path . DIRECTORY_SEPARATOR . 'purge_limiter.php',
'<?php' . PHP_EOL . '$GLOBALS[\'purge_limiter\'] = ' . $value . ';'
);
case 'salt':
return $this->_storeString(
$this->_path . DIRECTORY_SEPARATOR . 'salt.php',
'<?php # |' . $value . '|'
);
case 'traffic_limiter':
$this->_last_cache[$key] = $value;
return $this->_storeString(
$this->_path . DIRECTORY_SEPARATOR . 'traffic_limiter.php',
'<?php' . PHP_EOL . '$GLOBALS[\'traffic_limiter\'] = ' . var_export($this->_last_cache, true) . ';'
);
}
return false;
}
/**
* Load a value.
*
* @access public
* @param string $namespace
* @param string $key
* @return string
*/
public function getValue($namespace, $key = '')
{
switch ($namespace) {
case 'purge_limiter':
$file = $this->_path . DIRECTORY_SEPARATOR . 'purge_limiter.php';
if (is_readable($file)) {
require $file;
return $GLOBALS['purge_limiter'];
}
break;
case 'salt':
$file = $this->_path . DIRECTORY_SEPARATOR . 'salt.php';
if (is_readable($file)) {
$items = explode('|', file_get_contents($file));
if (is_array($items) && count($items) == 3) {
return $items[1];
}
}
break;
case 'traffic_limiter':
$file = $this->_path . DIRECTORY_SEPARATOR . 'traffic_limiter.php';
if (is_readable($file)) {
require $file;
$this->_last_cache = $GLOBALS['traffic_limiter'];
if (array_key_exists($key, $this->_last_cache)) {
return $this->_last_cache[$key];
}
}
break;
}
return '';
}
/**
* get the data
*
* @access public
* @param string $filename
* @return array|false $data
*/
private function _get($filename)
{
return Json::decode(
substr(
file_get_contents($filename),
strlen(self::PROTECTION_LINE . PHP_EOL)
)
);
}
/**
* Returns up to batch size number of paste ids that have expired
*
* @access private
* @param int $batchsize
* @return array
*/
protected function _getExpiredPastes($batchsize)
{
$pastes = array();
$count = 0;
$opened = 0;
$limit = $batchsize * 10; // try at most 10 times $batchsize pastes before giving up
$time = time();
$files = $this->getAllPastes();
shuffle($files);
foreach ($files as $pasteid) {
if ($this->exists($pasteid)) {
$data = $this->read($pasteid);
if (
array_key_exists('expire_date', $data['meta']) &&
$data['meta']['expire_date'] < $time
) {
$pastes[] = $pasteid;
if (++$count >= $batchsize) {
break;
}
}
if (++$opened >= $limit) {
break;
}
}
}
return $pastes;
}
/**
* @inheritDoc
*/
public function getAllPastes()
{
$pastes = array();
foreach (new GlobIterator($this->_path . self::PASTE_FILE_PATTERN) as $file) {
if ($file->isFile()) {
$pastes[] = $file->getBasename('.php');
}
}
return $pastes;
}
/**
* Convert paste id to storage path.
*
* The idea is to creates subdirectories in order to limit the number of files per directory.
* (A high number of files in a single directory can slow things down.)
* eg. "f468483c313401e8" will be stored in "data/f4/68/f468483c313401e8"
* High-trafic websites may want to deepen the directory structure (like Squid does).
*
* eg. input 'e3570978f9e4aa90' --> output 'data/e3/57/'
*
* @access private
* @param string $dataid
* @return string
*/
private function _dataid2path($dataid)
{
return $this->_path . DIRECTORY_SEPARATOR .
substr($dataid, 0, 2) . DIRECTORY_SEPARATOR .
substr($dataid, 2, 2) . DIRECTORY_SEPARATOR;
}
/**
* Convert paste id to discussion storage path.
*
* eg. input 'e3570978f9e4aa90' --> output 'data/e3/57/e3570978f9e4aa90.discussion/'
*
* @access private
* @param string $dataid
* @return string
*/
private function _dataid2discussionpath($dataid)
{
return $this->_dataid2path($dataid) . $dataid .
'.discussion' . DIRECTORY_SEPARATOR;
}
/**
* store the data
*
* @access public
* @param string $filename
* @param array $data
* @return bool
*/
private function _store($filename, array $data)
{
try {
return $this->_storeString(
$filename,
self::PROTECTION_LINE . PHP_EOL . Json::encode($data)
);
} catch (Exception $e) {
return false;
}
}
/**
* store a string
*
* @access public
* @param string $filename
* @param string $data
* @return bool
*/
private function _storeString($filename, $data)
{
// Create storage directory if it does not exist.
if (!is_dir($this->_path)) {
if (!@mkdir($this->_path, 0700)) {
return false;
}
}
$file = $this->_path . DIRECTORY_SEPARATOR . '.htaccess';
if (!is_file($file)) {
$writtenBytes = 0;
if ($fileCreated = @touch($file)) {
$writtenBytes = @file_put_contents(
$file,
self::HTACCESS_LINE . PHP_EOL,
LOCK_EX
);
}
if (
$fileCreated === false ||
$writtenBytes === false ||
$writtenBytes < strlen(self::HTACCESS_LINE . PHP_EOL)
) {
return false;
}
}
$fileCreated = true;
$writtenBytes = 0;
if (!is_file($filename)) {
$fileCreated = @touch($filename);
}
if ($fileCreated) {
$writtenBytes = @file_put_contents($filename, $data, LOCK_EX);
}
if ($fileCreated === false || $writtenBytes === false || $writtenBytes < strlen($data)) {
return false;
}
@chmod($filename, 0640); // protect file from access by other users on the host
return true;
}
/**
* rename a file, prepending the protection line at the beginning
*
* @access public
* @param string $srcFile
* @param string $destFile
* @return void
*/
private function _prependRename($srcFile, $destFile)
{
// don't overwrite already converted file
if (!is_readable($destFile)) {
$handle = fopen($srcFile, 'r', false, stream_context_create());
file_put_contents($destFile, self::PROTECTION_LINE . PHP_EOL);
file_put_contents($destFile, $handle, FILE_APPEND);
fclose($handle);
}
unlink($srcFile);
}
}