includes/MacBinary.php

   1 <?php
   2 /**
   3  * MacBinary signature checker and data fork extractor, for files
   4  * uploaded from Internet Explorer for Mac.
   5  *
   6  * Copyright (C) 2005 Brion Vibber <brion@pobox.com>
   7  * Portions based on Convert::BinHex by Eryq et al
   8  * http://www.mediawiki.org/
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License along
  21  * with this program; if not, write to the Free Software Foundation, Inc.,
  22  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  23  * http://www.gnu.org/copyleft/gpl.html
  24  *
  25  * @ingroup SpecialPage
  26  */
  27
  28 class MacBinary {
  29         function __construct( $filename ) {
  30                 $this->open( $filename );
  31                 $this->loadHeader();
  32         }
  33
  34         /**
  35          * The file must be seekable, such as local filesystem.
  36          * Remote URLs probably won't work.
  37          *
  38          * @param string $filename
  39          */
  40         function open( $filename ) {
  41                 $this->valid = false;
  42                 $this->version = 0;
  43                 $this->filename = '';
  44                 $this->dataLength = 0;
  45                 $this->resourceLength = 0;
  46                 $this->handle = fopen( $filename, 'rb' );
  47         }
  48
  49         /**
  50          * Does this appear to be a valid MacBinary archive?
  51          * @return bool
  52          */
  53         function isValid() {
  54                 return $this->valid;
  55         }
  56
  57         /**
  58          * Get length of data fork
  59          * @return int
  60          */
  61         function dataForkLength() {
  62                 return $this->dataLength;
  63         }
  64
  65         /**
  66          * Copy the data fork to an external file or resource.
  67          * @param resource $destination
  68          * @return bool
  69          */
  70         function extractData( $destination ) {
  71                 if( !$this->isValid() ) {
  72                         return false;
  73                 }
  74
  75                 // Data fork appears immediately after header
  76                 fseek( $this->handle, 128 );
  77                 return $this->copyBytesTo( $destination, $this->dataLength );
  78         }
  79
  80         /**
  81          *
  82          */
  83         function close() {
  84                 fclose( $this->handle );
  85         }
  86
  87         // --------------------------------------------------------------
  88
  89         /**
  90          * Check if the given file appears to be MacBinary-encoded,
  91          * as Internet Explorer on Mac OS may provide for unknown types.
  92          * http://www.lazerware.com/formats/macbinary/macbinary_iii.html
  93          * If ok, load header data.
  94          *
  95          * @return bool
  96          * @access private
  97          */
  98         function loadHeader() {
  99                 $fname = 'MacBinary::loadHeader';
 100
 101                 fseek( $this->handle, 0 );
 102                 $head = fread( $this->handle, 128 );
 103                 #$this->hexdump( $head );
 104
 105                 if( strlen( $head ) < 128 ) {
 106                         wfDebug( "$fname: couldn't read full MacBinary header\n" );
 107                         return false;
 108                 }
 109
 110                 if( $head{0} != "\x00" || $head{74} != "\x00" ) {
 111                         wfDebug( "$fname: header bytes 0 and 74 not null\n" );
 112                         return false;
 113                 }
 114
 115                 $signature = substr( $head, 102, 4 );
 116                 $a = unpack( "ncrc", substr( $head, 124, 2 ) );
 117                 $storedCRC = $a['crc'];
 118                 $calculatedCRC = $this->calcCRC( substr( $head, 0, 124 ) );
 119                 if( $storedCRC == $calculatedCRC ) {
 120                         if( $signature == 'mBIN' ) {
 121                                 $this->version = 3;
 122                         } else {
 123                                 $this->version = 2;
 124                         }
 125                 } else {
 126                         $crc = sprintf( "%x != %x", $storedCRC, $calculatedCRC );
 127                         if( $storedCRC == 0 && $head{82} == "\x00" &&
 128                                 substr( $head, 101, 24 ) == str_repeat( "\x00", 24 ) ) {
 129                                 wfDebug( "$fname: no CRC, looks like MacBinary I\n" );
 130                                 $this->version = 1;
 131                         } elseif( $signature == 'mBIN' && $storedCRC == 0x185 ) {
 132                                 // Mac IE 5.0 seems to insert this value in the CRC field.
 133                                 // 5.2.3 works correctly; don't know about other versions.
 134                                 wfDebug( "$fname: CRC doesn't match ($crc), looks like Mac IE 5.0\n" );
 135                                 $this->version = 3;
 136                         } else {
 137                                 wfDebug( "$fname: CRC doesn't match ($crc) and not MacBinary I\n" );
 138                                 return false;
 139                         }
 140                 }
 141
 142                 $nameLength = ord( $head{1} );
 143                 if( $nameLength < 1 || $nameLength > 63 ) {
 144                         wfDebug( "$fname: invalid filename size $nameLength\n" );
 145                         return false;
 146                 }
 147                 $this->filename = substr( $head, 2, $nameLength );
 148
 149                 $forks = unpack( "Ndata/Nresource", substr( $head, 83, 8 ) );
 150                 $this->dataLength = $forks['data'];
 151                 $this->resourceLength = $forks['resource'];
 152                 $maxForkLength = 0x7fffff;
 153
 154                 if( $this->dataLength < 0 || $this->dataLength > $maxForkLength ) {
 155                         wfDebug( "$fname: invalid data fork length $this->dataLength\n" );
 156                         return false;
 157                 }
 158
 159                 if( $this->resourceLength < 0 || $this->resourceLength > $maxForkLength ) {
 160                         wfDebug( "$fname: invalid resource fork size $this->resourceLength\n" );
 161                         return false;
 162                 }
 163
 164                 wfDebug( "$fname: appears to be MacBinary $this->version, data length $this->dataLength\n" );
 165                 $this->valid = true;
 166                 return true;
 167         }
 168
 169         /**
 170          * Calculate a 16-bit CRC value as for MacBinary headers.
 171          * Adapted from perl5 Convert::BinHex by Eryq,
 172          * based on the mcvert utility (Doug Moore, April '87),
 173          * with magic array thingy by Jim Van Verth.
 174          * http://search.cpan.org/~eryq/Convert-BinHex-1.119/lib/Convert/BinHex.pm
 175          *
 176          * @param string $data
 177          * @param int $seed
 178          * @return int
 179          * @access private
 180          */
 181         function calcCRC( $data, $seed = 0 ) {
 182                 # An array useful for CRC calculations that use 0x1021 as the "seed":
 183                 $MAGIC = array(
 184                         0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
 185                         0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,
 186                         0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
 187                         0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de,
 188                         0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485,
 189                         0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
 190                         0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4,
 191                         0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc,
 192                         0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823,
 193                         0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b,
 194                         0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12,
 195                         0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,
 196                         0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41,
 197                         0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49,
 198                         0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70,
 199                         0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78,
 200                         0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f,
 201                         0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
 202                         0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e,
 203                         0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256,
 204                         0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,
 205                         0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
 206                         0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c,
 207                         0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,
 208                         0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab,
 209                         0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3,
 210                         0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
 211                         0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92,
 212                         0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9,
 213                         0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1,
 214                         0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8,
 215                         0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0
 216                 );
 217                 $len = strlen( $data );
 218                 $crc = $seed;
 219                 for( $i = 0; $i < $len; $i++ ) {
 220                         $crc ^= ord( $data{$i} ) << 8;
 221                         $crc &= 0xFFFF;
 222                         $crc = ($crc << 8) ^ $MAGIC[$crc >> 8];
 223                         $crc &= 0xFFFF;
 224                 }
 225                 return $crc;
 226         }
 227
 228         /**
 229          * @param resource $destination
 230          * @param int $bytesToCopy
 231          * @return bool
 232          * @access private
 233          */
 234         function copyBytesTo( $destination, $bytesToCopy ) {
 235                 $bufferSize = 65536;
 236                 for( $remaining = $bytesToCopy; $remaining > 0; $remaining -= $bufferSize ) {
 237                         $thisChunkSize = min( $remaining, $bufferSize );
 238                         $buffer = fread( $this->handle, $thisChunkSize );
 239                         fwrite( $destination, $buffer );
 240                 }
 241         }
 242
 243         /**
 244          * Hex dump of the header for debugging
 245          * @access private
 246          */
 247         function hexdump( $data ) {
 248                 global $wgDebugLogFile;
 249                 if( !$wgDebugLogFile ) return;
 250
 251                 $width = 16;
 252                 $at = 0;
 253                 for( $remaining = strlen( $data ); $remaining > 0; $remaining -= $width ) {
 254                         $line = sprintf( "%04x:", $at );
 255                         $printable = '';
 256                         for( $i = 0; $i < $width && $remaining - $i > 0; $i++ ) {
 257                                 $byte = ord( $data{$at++} );
 258                                 $line .= sprintf( " %02x", $byte );
 259                                 $printable .= ($byte >= 32 && $byte <= 126 )
 260                                         ? chr( $byte )
 261                                         : '.';
 262                         }
 263                         if( $i < $width ) {
 264                                 $line .= str_repeat( '   ', $width - $i );
 265                         }
 266                         wfDebug( "MacBinary: $line $printable\n" );
 267                 }
 268         }
 269 }