name : module.misc.torrent.php <?php ///////////////////////////////////////////////////////////////// /// getID3() by James Heinrich <info@getid3.org> // // available at https://github.com/JamesHeinrich/getID3 // // or https://www.getid3.org // // or http://getid3.sourceforge.net // // see readme.txt for more details // ///////////////////////////////////////////////////////////////// // // // module.misc.torrent.php // // module for analyzing .torrent files // // dependencies: NONE // // /// ///////////////////////////////////////////////////////////////// if (!defined('GETID3_INCLUDEPATH')) { // prevent path-exposing attacks that access modules directly on public webservers exit; } class getid3_torrent extends getid3_handler { /** * Assume all .torrent files are less than 1MB and just read entire thing into memory for easy processing. * Override this value if you need to process files larger than 1MB * * @var int */ public $max_torrent_filesize = 1048576; /** * calculated InfoHash (SHA1 of the entire "info" Dictionary) * * @var string */ private $infohash = ''; const PIECE_HASHLENGTH = 20; // number of bytes the SHA1 hash is for each piece /** * @return bool */ public function Analyze() { $info = &$this->getid3->info; $filesize = $info['avdataend'] - $info['avdataoffset']; if ($filesize > $this->max_torrent_filesize) { // $this->error('File larger ('.number_format($filesize).' bytes) than $max_torrent_filesize ('.number_format($this->max_torrent_filesize).' bytes), increase getid3_torrent->max_torrent_filesize if needed'); return false; } $this->fseek($info['avdataoffset']); $TORRENT = $this->fread($filesize); $offset = 0; if (!preg_match('#^(d8\\:announce|d7\\:comment)#', $TORRENT)) { $this->error('Expecting "d8:announce" or "d7:comment" at '.$info['avdataoffset'].', found "'.substr($TORRENT, $offset, 12).'" instead.'); return false; } $info['fileformat'] = 'torrent'; $info['torrent'] = $this->NextEntity($TORRENT, $offset); if ($this->infohash) { $info['torrent']['infohash'] = $this->infohash; } if (empty($info['torrent']['info']['length']) && !empty($info['torrent']['info']['files'][0]['length'])) { $info['torrent']['info']['length'] = 0; foreach ($info['torrent']['info']['files'] as $key => $filedetails) { $info['torrent']['info']['length'] += $filedetails['length']; } } if (!empty($info['torrent']['info']['length']) && !empty($info['torrent']['info']['piece length']) && !empty($info['torrent']['info']['pieces'])) { $num_pieces_size = ceil($info['torrent']['info']['length'] / $info['torrent']['info']['piece length']); $num_pieces_hash = strlen($info['torrent']['info']['pieces']) / getid3_torrent::PIECE_HASHLENGTH; // should be concatenated 20-byte SHA1 hashes if ($num_pieces_hash == $num_pieces_size) { $info['torrent']['info']['piece_hash'] = array(); for ($i = 0; $i < $num_pieces_size; $i++) { $info['torrent']['info']['piece_hash'][$i] = ''; for ($j = 0; $j < getid3_torrent::PIECE_HASHLENGTH; $j++) { $info['torrent']['info']['piece_hash'][$i] .= sprintf('%02x', ord($info['torrent']['info']['pieces'][(($i * getid3_torrent::PIECE_HASHLENGTH) + $j)])); } } unset($info['torrent']['info']['pieces']); } else { $this->warning('found '.$num_pieces_size.' pieces based on file/chunk size; found '.$num_pieces_hash.' pieces in hash table'); } } if (!empty($info['torrent']['info']['name']) && !empty($info['torrent']['info']['length']) && !isset($info['torrent']['info']['files'])) { // single-file torrent $info['torrent']['files'] = array($info['torrent']['info']['name'] => $info['torrent']['info']['length']); } elseif (!empty($info['torrent']['info']['files'])) { // multi-file torrent $info['torrent']['files'] = array(); foreach ($info['torrent']['info']['files'] as $key => $filedetails) { $info['torrent']['files'][implode('/', $filedetails['path'])] = $filedetails['length']; } } else { $this->warning('no files found'); } return true; } /** * @return string|array|int|bool */ public function NextEntity(&$TORRENT, &$offset) { // https://fileformats.fandom.com/wiki/Torrent_file // https://en.wikipedia.org/wiki/Torrent_file // https://en.wikipedia.org/wiki/Bencode if ($offset >= strlen($TORRENT)) { $this->error('cannot read beyond end of file '.$offset); return false; } $type = $TORRENT[$offset++]; if ($type == 'i') { // Integers are stored as i<integer>e: // i90e $value = $this->ReadSequentialDigits($TORRENT, $offset, true); if ($TORRENT[$offset++] == 'e') { //echo '<li>int: '.$value.'</li>'; return (int) $value; } $this->error('unexpected('.__LINE__.') input "'.$value.'" at offset '.($offset - 1)); return false; } elseif ($type == 'd') { // Dictionaries are stored as d[key1][value1][key2][value2][...]e. Keys and values appear alternately. // Keys must be strings and must be ordered alphabetically. // For example, {apple-red, lemon-yellow, violet-blue, banana-yellow} is stored as: // d5:apple3:red6:banana6:yellow5:lemon6:yellow6:violet4:bluee $values = array(); //echo 'DICTIONARY @ '.$offset.'<ul>'; $info_dictionary_start = null; // dummy declaration to prevent "Variable might not be defined" warnings while (true) { if ($TORRENT[$offset] === 'e') { break; } $thisentry = array(); $key = $this->NextEntity($TORRENT, $offset); if ($key == 'info') { $info_dictionary_start = $offset; } if ($key === false) { $this->error('unexpected('.__LINE__.') input at offset '.$offset); return false; } $value = $this->NextEntity($TORRENT, $offset); if ($key == 'info') { $info_dictionary_end = $offset; $this->infohash = sha1(substr($TORRENT, $info_dictionary_start, $info_dictionary_end - $info_dictionary_start)); } if ($value === false) { $this->error('unexpected('.__LINE__.') input at offset '.$offset); return false; } $values[$key] = $value; } if ($TORRENT[$offset++] == 'e') { //echo '</ul>'; return $values; } $this->error('unexpected('.__LINE__.') input "'.$TORRENT[($offset - 1)].'" at offset '.($offset - 1)); return false; } elseif ($type == 'l') { //echo 'LIST @ '.$offset.'<ul>'; // Lists are stored as l[value 1][value2][value3][...]e. For example, {spam, eggs, cheeseburger} is stored as: // l4:spam4:eggs12:cheeseburgere $values = array(); while (true) { if ($TORRENT[$offset] === 'e') { break; } $NextEntity = $this->NextEntity($TORRENT, $offset); if ($NextEntity === false) { $this->error('unexpected('.__LINE__.') input at offset '.($offset - 1)); return false; } $values[] = $NextEntity; } if ($TORRENT[$offset++] == 'e') { //echo '</ul>'; return $values; } $this->error('unexpected('.__LINE__.') input "'.$TORRENT[($offset - 1)].'" at offset '.($offset - 1)); return false; } elseif (ctype_digit($type)) { // Strings are stored as <length of string>:<string>: // 4:wiki $length = $type; while (true) { $char = $TORRENT[$offset++]; if ($char == ':') { break; } elseif (!ctype_digit($char)) { $this->error('unexpected('.__LINE__.') input "'.$char.'" at offset '.($offset - 1)); return false; } $length .= $char; } if (($offset + $length) > strlen($TORRENT)) { $this->error('string at offset '.$offset.' claims to be '.$length.' bytes long but only '.(strlen($TORRENT) - $offset).' bytes of data left in file'); return false; } $string = substr($TORRENT, $offset, $length); $offset += $length; //echo '<li>string: '.$string.'</li>'; return (string) $string; } else { $this->error('unexpected('.__LINE__.') input "'.$type.'" at offset '.($offset - 1)); return false; } } /** * @return string */ public function ReadSequentialDigits(&$TORRENT, &$offset, $allow_negative=false) { $start_offset = $offset; $value = ''; while (true) { $char = $TORRENT[$offset++]; if (!ctype_digit($char)) { if ($allow_negative && ($char == '-') && (strlen($value) == 0)) { // allow negative-sign if first character and $allow_negative enabled } else { $offset--; break; } } $value .= $char; } if (($value[0] === '0') && ($value !== '0')) { $this->warning('illegal zero-padded number "'.$value.'" at offset '.$start_offset); } return $value; } }