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Diffstat (limited to 'includes/ZipDirectoryReader.php')
| -rw-r--r-- | includes/ZipDirectoryReader.php | 712 |
1 files changed, 0 insertions, 712 deletions
diff --git a/includes/ZipDirectoryReader.php b/includes/ZipDirectoryReader.php deleted file mode 100644 index 307efcea..00000000 --- a/includes/ZipDirectoryReader.php +++ /dev/null @@ -1,712 +0,0 @@ -<?php -/** - * ZIP file directories reader, for the purposes of upload verification. - * - * 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. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License along - * with this program; if not, write to the Free Software Foundation, Inc., - * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. - * http://www.gnu.org/copyleft/gpl.html - * - * @file - */ - -/** - * A class for reading ZIP file directories, for the purposes of upload - * verification. - * - * Only a functional interface is provided: ZipFileReader::read(). No access is - * given to object instances. - * - */ -class ZipDirectoryReader { - /** - * Read a ZIP file and call a function for each file discovered in it. - * - * Because this class is aimed at verification, an error is raised on - * suspicious or ambiguous input, instead of emulating some standard - * behavior. - * - * @param string $fileName The archive file name - * @param array $callback The callback function. It will be called for each file - * with a single associative array each time, with members: - * - * - name: The file name. Directories conventionally have a trailing - * slash. - * - * - mtime: The file modification time, in MediaWiki 14-char format - * - * - size: The uncompressed file size - * - * @param array $options An associative array of read options, with the option - * name in the key. This may currently contain: - * - * - zip64: If this is set to true, then we will emulate a - * library with ZIP64 support, like OpenJDK 7. If it is set to - * false, then we will emulate a library with no knowledge of - * ZIP64. - * - * NOTE: The ZIP64 code is untested and probably doesn't work. It - * turned out to be easier to just reject ZIP64 archive uploads, - * since they are likely to be very rare. Confirming safety of a - * ZIP64 file is fairly complex. What do you do with a file that is - * ambiguous and broken when read with a non-ZIP64 reader, but valid - * when read with a ZIP64 reader? This situation is normal for a - * valid ZIP64 file, and working out what non-ZIP64 readers will make - * of such a file is not trivial. - * - * @return Status object. The following fatal errors are defined: - * - * - zip-file-open-error: The file could not be opened. - * - * - zip-wrong-format: The file does not appear to be a ZIP file. - * - * - zip-bad: There was something wrong or ambiguous about the file - * data. - * - * - zip-unsupported: The ZIP file uses features which - * ZipDirectoryReader does not support. - * - * The default messages for those fatal errors are written in a way that - * makes sense for upload verification. - * - * If a fatal error is returned, more information about the error will be - * available in the debug log. - * - * Note that the callback function may be called any number of times before - * a fatal error is returned. If this occurs, the data sent to the callback - * function should be discarded. - */ - public static function read( $fileName, $callback, $options = array() ) { - $zdr = new self( $fileName, $callback, $options ); - return $zdr->execute(); - } - - /** The file name */ - var $fileName; - - /** The opened file resource */ - var $file; - - /** The cached length of the file, or null if it has not been loaded yet. */ - var $fileLength; - - /** A segmented cache of the file contents */ - var $buffer; - - /** The file data callback */ - var $callback; - - /** The ZIP64 mode */ - var $zip64 = false; - - /** Stored headers */ - var $eocdr, $eocdr64, $eocdr64Locator; - - var $data; - - /** The "extra field" ID for ZIP64 central directory entries */ - const ZIP64_EXTRA_HEADER = 0x0001; - - /** The segment size for the file contents cache */ - const SEGSIZE = 16384; - - /** The index of the "general field" bit for UTF-8 file names */ - const GENERAL_UTF8 = 11; - - /** The index of the "general field" bit for central directory encryption */ - const GENERAL_CD_ENCRYPTED = 13; - - /** - * Private constructor - */ - protected function __construct( $fileName, $callback, $options ) { - $this->fileName = $fileName; - $this->callback = $callback; - - if ( isset( $options['zip64'] ) ) { - $this->zip64 = $options['zip64']; - } - } - - /** - * Read the directory according to settings in $this. - * - * @return Status - */ - function execute() { - $this->file = fopen( $this->fileName, 'r' ); - $this->data = array(); - if ( !$this->file ) { - return Status::newFatal( 'zip-file-open-error' ); - } - - $status = Status::newGood(); - try { - $this->readEndOfCentralDirectoryRecord(); - if ( $this->zip64 ) { - list( $offset, $size ) = $this->findZip64CentralDirectory(); - $this->readCentralDirectory( $offset, $size ); - } else { - if ( $this->eocdr['CD size'] == 0xffffffff - || $this->eocdr['CD offset'] == 0xffffffff - || $this->eocdr['CD entries total'] == 0xffff ) - { - $this->error( 'zip-unsupported', 'Central directory header indicates ZIP64, ' . - 'but we are in legacy mode. Rejecting this upload is necessary to avoid ' . - 'opening vulnerabilities on clients using OpenJDK 7 or later.' ); - } - - list( $offset, $size ) = $this->findOldCentralDirectory(); - $this->readCentralDirectory( $offset, $size ); - } - } catch ( ZipDirectoryReaderError $e ) { - $status->fatal( $e->getErrorCode() ); - } - - fclose( $this->file ); - return $status; - } - - /** - * Throw an error, and log a debug message - */ - function error( $code, $debugMessage ) { - wfDebug( __CLASS__ . ": Fatal error: $debugMessage\n" ); - throw new ZipDirectoryReaderError( $code ); - } - - /** - * Read the header which is at the end of the central directory, - * unimaginatively called the "end of central directory record" by the ZIP - * spec. - */ - function readEndOfCentralDirectoryRecord() { - $info = array( - 'signature' => 4, - 'disk' => 2, - 'CD start disk' => 2, - 'CD entries this disk' => 2, - 'CD entries total' => 2, - 'CD size' => 4, - 'CD offset' => 4, - 'file comment length' => 2, - ); - $structSize = $this->getStructSize( $info ); - $startPos = $this->getFileLength() - 65536 - $structSize; - if ( $startPos < 0 ) { - $startPos = 0; - } - - $block = $this->getBlock( $startPos ); - $sigPos = strrpos( $block, "PK\x05\x06" ); - if ( $sigPos === false ) { - $this->error( 'zip-wrong-format', - "zip file lacks EOCDR signature. It probably isn't a zip file." ); - } - - $this->eocdr = $this->unpack( substr( $block, $sigPos ), $info ); - $this->eocdr['EOCDR size'] = $structSize + $this->eocdr['file comment length']; - - if ( $structSize + $this->eocdr['file comment length'] != strlen( $block ) - $sigPos ) { - $this->error( 'zip-bad', 'trailing bytes after the end of the file comment' ); - } - if ( $this->eocdr['disk'] !== 0 - || $this->eocdr['CD start disk'] !== 0 ) - { - $this->error( 'zip-unsupported', 'more than one disk (in EOCDR)' ); - } - $this->eocdr += $this->unpack( - $block, - array( 'file comment' => array( 'string', $this->eocdr['file comment length'] ) ), - $sigPos + $structSize ); - $this->eocdr['position'] = $startPos + $sigPos; - } - - /** - * Read the header called the "ZIP64 end of central directory locator". An - * error will be raised if it does not exist. - */ - function readZip64EndOfCentralDirectoryLocator() { - $info = array( - 'signature' => array( 'string', 4 ), - 'eocdr64 start disk' => 4, - 'eocdr64 offset' => 8, - 'number of disks' => 4, - ); - $structSize = $this->getStructSize( $info ); - - $block = $this->getBlock( $this->getFileLength() - $this->eocdr['EOCDR size'] - - $structSize, $structSize ); - $this->eocdr64Locator = $data = $this->unpack( $block, $info ); - - if ( $data['signature'] !== "PK\x06\x07" ) { - // Note: Java will allow this and continue to read the - // EOCDR64, so we have to reject the upload, we can't - // just use the EOCDR header instead. - $this->error( 'zip-bad', 'wrong signature on Zip64 end of central directory locator' ); - } - } - - /** - * Read the header called the "ZIP64 end of central directory record". It - * may replace the regular "end of central directory record" in ZIP64 files. - */ - function readZip64EndOfCentralDirectoryRecord() { - if ( $this->eocdr64Locator['eocdr64 start disk'] != 0 - || $this->eocdr64Locator['number of disks'] != 0 ) - { - $this->error( 'zip-unsupported', 'more than one disk (in EOCDR64 locator)' ); - } - - $info = array( - 'signature' => array( 'string', 4 ), - 'EOCDR64 size' => 8, - 'version made by' => 2, - 'version needed' => 2, - 'disk' => 4, - 'CD start disk' => 4, - 'CD entries this disk' => 8, - 'CD entries total' => 8, - 'CD size' => 8, - 'CD offset' => 8 - ); - $structSize = $this->getStructSize( $info ); - $block = $this->getBlock( $this->eocdr64Locator['eocdr64 offset'], $structSize ); - $this->eocdr64 = $data = $this->unpack( $block, $info ); - if ( $data['signature'] !== "PK\x06\x06" ) { - $this->error( 'zip-bad', 'wrong signature on Zip64 end of central directory record' ); - } - if ( $data['disk'] !== 0 - || $data['CD start disk'] !== 0 ) - { - $this->error( 'zip-unsupported', 'more than one disk (in EOCDR64)' ); - } - } - - /** - * Find the location of the central directory, as would be seen by a - * non-ZIP64 reader. - * - * @return List containing offset, size and end position. - */ - function findOldCentralDirectory() { - $size = $this->eocdr['CD size']; - $offset = $this->eocdr['CD offset']; - $endPos = $this->eocdr['position']; - - // Some readers use the EOCDR position instead of the offset field - // to find the directory, so to be safe, we check if they both agree. - if ( $offset + $size != $endPos ) { - $this->error( 'zip-bad', 'the central directory does not immediately precede the end ' . - 'of central directory record' ); - } - return array( $offset, $size ); - } - - /** - * Find the location of the central directory, as would be seen by a - * ZIP64-compliant reader. - * - * @return array List containing offset, size and end position. - */ - function findZip64CentralDirectory() { - // The spec is ambiguous about the exact rules of precedence between the - // ZIP64 headers and the original headers. Here we follow zip_util.c - // from OpenJDK 7. - $size = $this->eocdr['CD size']; - $offset = $this->eocdr['CD offset']; - $numEntries = $this->eocdr['CD entries total']; - $endPos = $this->eocdr['position']; - if ( $size == 0xffffffff - || $offset == 0xffffffff - || $numEntries == 0xffff ) - { - $this->readZip64EndOfCentralDirectoryLocator(); - - if ( isset( $this->eocdr64Locator['eocdr64 offset'] ) ) { - $this->readZip64EndOfCentralDirectoryRecord(); - if ( isset( $this->eocdr64['CD offset'] ) ) { - $size = $this->eocdr64['CD size']; - $offset = $this->eocdr64['CD offset']; - $endPos = $this->eocdr64Locator['eocdr64 offset']; - } - } - } - // Some readers use the EOCDR position instead of the offset field - // to find the directory, so to be safe, we check if they both agree. - if ( $offset + $size != $endPos ) { - $this->error( 'zip-bad', 'the central directory does not immediately precede the end ' . - 'of central directory record' ); - } - return array( $offset, $size ); - } - - /** - * Read the central directory at the given location - */ - function readCentralDirectory( $offset, $size ) { - $block = $this->getBlock( $offset, $size ); - - $fixedInfo = array( - 'signature' => array( 'string', 4 ), - 'version made by' => 2, - 'version needed' => 2, - 'general bits' => 2, - 'compression method' => 2, - 'mod time' => 2, - 'mod date' => 2, - 'crc-32' => 4, - 'compressed size' => 4, - 'uncompressed size' => 4, - 'name length' => 2, - 'extra field length' => 2, - 'comment length' => 2, - 'disk number start' => 2, - 'internal attrs' => 2, - 'external attrs' => 4, - 'local header offset' => 4, - ); - $fixedSize = $this->getStructSize( $fixedInfo ); - - $pos = 0; - while ( $pos < $size ) { - $data = $this->unpack( $block, $fixedInfo, $pos ); - $pos += $fixedSize; - - if ( $data['signature'] !== "PK\x01\x02" ) { - $this->error( 'zip-bad', 'Invalid signature found in directory entry' ); - } - - $variableInfo = array( - 'name' => array( 'string', $data['name length'] ), - 'extra field' => array( 'string', $data['extra field length'] ), - 'comment' => array( 'string', $data['comment length'] ), - ); - $data += $this->unpack( $block, $variableInfo, $pos ); - $pos += $this->getStructSize( $variableInfo ); - - if ( $this->zip64 && ( - $data['compressed size'] == 0xffffffff - || $data['uncompressed size'] == 0xffffffff - || $data['local header offset'] == 0xffffffff ) ) - { - $zip64Data = $this->unpackZip64Extra( $data['extra field'] ); - if ( $zip64Data ) { - $data = $zip64Data + $data; - } - } - - if ( $this->testBit( $data['general bits'], self::GENERAL_CD_ENCRYPTED ) ) { - $this->error( 'zip-unsupported', 'central directory encryption is not supported' ); - } - - // Convert the timestamp into MediaWiki format - // For the format, please see the MS-DOS 2.0 Programmer's Reference, - // pages 3-5 and 3-6. - $time = $data['mod time']; - $date = $data['mod date']; - - $year = 1980 + ( $date >> 9 ); - $month = ( $date >> 5 ) & 15; - $day = $date & 31; - $hour = ( $time >> 11 ) & 31; - $minute = ( $time >> 5 ) & 63; - $second = ( $time & 31 ) * 2; - $timestamp = sprintf( "%04d%02d%02d%02d%02d%02d", - $year, $month, $day, $hour, $minute, $second ); - - // Convert the character set in the file name - if ( !function_exists( 'iconv' ) - || $this->testBit( $data['general bits'], self::GENERAL_UTF8 ) ) - { - $name = $data['name']; - } else { - $name = iconv( 'CP437', 'UTF-8', $data['name'] ); - } - - // Compile a data array for the user, with a sensible format - $userData = array( - 'name' => $name, - 'mtime' => $timestamp, - 'size' => $data['uncompressed size'], - ); - call_user_func( $this->callback, $userData ); - } - } - - /** - * Interpret ZIP64 "extra field" data and return an associative array. - * @return array|bool - */ - function unpackZip64Extra( $extraField ) { - $extraHeaderInfo = array( - 'id' => 2, - 'size' => 2, - ); - $extraHeaderSize = $this->getStructSize( $extraHeaderInfo ); - - $zip64ExtraInfo = array( - 'uncompressed size' => 8, - 'compressed size' => 8, - 'local header offset' => 8, - 'disk number start' => 4, - ); - - $extraPos = 0; - while ( $extraPos < strlen( $extraField ) ) { - $extra = $this->unpack( $extraField, $extraHeaderInfo, $extraPos ); - $extraPos += $extraHeaderSize; - $extra += $this->unpack( $extraField, - array( 'data' => array( 'string', $extra['size'] ) ), - $extraPos ); - $extraPos += $extra['size']; - - if ( $extra['id'] == self::ZIP64_EXTRA_HEADER ) { - return $this->unpack( $extra['data'], $zip64ExtraInfo ); - } - } - - return false; - } - - /** - * Get the length of the file. - */ - function getFileLength() { - if ( $this->fileLength === null ) { - $stat = fstat( $this->file ); - $this->fileLength = $stat['size']; - } - return $this->fileLength; - } - - /** - * Get the file contents from a given offset. If there are not enough bytes - * in the file to satisfy the request, an exception will be thrown. - * - * @param int $start The byte offset of the start of the block. - * @param int $length The number of bytes to return. If omitted, the remainder - * of the file will be returned. - * - * @return string - */ - function getBlock( $start, $length = null ) { - $fileLength = $this->getFileLength(); - if ( $start >= $fileLength ) { - $this->error( 'zip-bad', "getBlock() requested position $start, " . - "file length is $fileLength" ); - } - if ( $length === null ) { - $length = $fileLength - $start; - } - $end = $start + $length; - if ( $end > $fileLength ) { - $this->error( 'zip-bad', "getBlock() requested end position $end, " . - "file length is $fileLength" ); - } - $startSeg = floor( $start / self::SEGSIZE ); - $endSeg = ceil( $end / self::SEGSIZE ); - - $block = ''; - for ( $segIndex = $startSeg; $segIndex <= $endSeg; $segIndex++ ) { - $block .= $this->getSegment( $segIndex ); - } - - $block = substr( $block, - $start - $startSeg * self::SEGSIZE, - $length ); - - if ( strlen( $block ) < $length ) { - $this->error( 'zip-bad', 'getBlock() returned an unexpectedly small amount of data' ); - } - - return $block; - } - - /** - * Get a section of the file starting at position $segIndex * self::SEGSIZE, - * of length self::SEGSIZE. The result is cached. This is a helper function - * for getBlock(). - * - * If there are not enough bytes in the file to satisfy the request, the - * return value will be truncated. If a request is made for a segment beyond - * the end of the file, an empty string will be returned. - * @return string - */ - function getSegment( $segIndex ) { - if ( !isset( $this->buffer[$segIndex] ) ) { - $bytePos = $segIndex * self::SEGSIZE; - if ( $bytePos >= $this->getFileLength() ) { - $this->buffer[$segIndex] = ''; - return ''; - } - if ( fseek( $this->file, $bytePos ) ) { - $this->error( 'zip-bad', "seek to $bytePos failed" ); - } - $seg = fread( $this->file, self::SEGSIZE ); - if ( $seg === false ) { - $this->error( 'zip-bad', "read from $bytePos failed" ); - } - $this->buffer[$segIndex] = $seg; - } - return $this->buffer[$segIndex]; - } - - /** - * Get the size of a structure in bytes. See unpack() for the format of $struct. - * @return int - */ - function getStructSize( $struct ) { - $size = 0; - foreach ( $struct as $type ) { - if ( is_array( $type ) ) { - list( , $fieldSize ) = $type; - $size += $fieldSize; - } else { - $size += $type; - } - } - return $size; - } - - /** - * Unpack a binary structure. This is like the built-in unpack() function - * except nicer. - * - * @param string $string The binary data input - * - * @param array $struct An associative array giving structure members and their - * types. In the key is the field name. The value may be either an - * integer, in which case the field is a little-endian unsigned integer - * encoded in the given number of bytes, or an array, in which case the - * first element of the array is the type name, and the subsequent - * elements are type-dependent parameters. Only one such type is defined: - * - "string": The second array element gives the length of string. - * Not null terminated. - * - * @param int $offset The offset into the string at which to start unpacking. - * - * @throws MWException - * @return array Unpacked associative array. Note that large integers in the input - * may be represented as floating point numbers in the return value, so - * the use of weak comparison is advised. - */ - function unpack( $string, $struct, $offset = 0 ) { - $size = $this->getStructSize( $struct ); - if ( $offset + $size > strlen( $string ) ) { - $this->error( 'zip-bad', 'unpack() would run past the end of the supplied string' ); - } - - $data = array(); - $pos = $offset; - foreach ( $struct as $key => $type ) { - if ( is_array( $type ) ) { - list( $typeName, $fieldSize ) = $type; - switch ( $typeName ) { - case 'string': - $data[$key] = substr( $string, $pos, $fieldSize ); - $pos += $fieldSize; - break; - default: - throw new MWException( __METHOD__ . ": invalid type \"$typeName\"" ); - } - } else { - // Unsigned little-endian integer - $length = intval( $type ); - - // Calculate the value. Use an algorithm which automatically - // upgrades the value to floating point if necessary. - $value = 0; - for ( $i = $length - 1; $i >= 0; $i-- ) { - $value *= 256; - $value += ord( $string[$pos + $i] ); - } - - // Throw an exception if there was loss of precision - if ( $value > pow( 2, 52 ) ) { - $this->error( 'zip-unsupported', 'number too large to be stored in a double. ' . - 'This could happen if we tried to unpack a 64-bit structure ' . - 'at an invalid location.' ); - } - $data[$key] = $value; - $pos += $length; - } - } - - return $data; - } - - /** - * Returns a bit from a given position in an integer value, converted to - * boolean. - * - * @param $value integer - * @param int $bitIndex The index of the bit, where 0 is the LSB. - * @return bool - */ - function testBit( $value, $bitIndex ) { - return (bool)( ( $value >> $bitIndex ) & 1 ); - } - - /** - * Debugging helper function which dumps a string in hexdump -C format. - */ - function hexDump( $s ) { - $n = strlen( $s ); - for ( $i = 0; $i < $n; $i += 16 ) { - printf( "%08X ", $i ); - for ( $j = 0; $j < 16; $j++ ) { - print " "; - if ( $j == 8 ) { - print " "; - } - if ( $i + $j >= $n ) { - print " "; - } else { - printf( "%02X", ord( $s[$i + $j] ) ); - } - } - - print " |"; - for ( $j = 0; $j < 16; $j++ ) { - if ( $i + $j >= $n ) { - print " "; - } elseif ( ctype_print( $s[$i + $j] ) ) { - print $s[$i + $j]; - } else { - print '.'; - } - } - print "|\n"; - } - } -} - -/** - * Internal exception class. Will be caught by private code. - */ -class ZipDirectoryReaderError extends Exception { - var $errorCode; - - function __construct( $code ) { - $this->errorCode = $code; - parent::__construct( "ZipDirectoryReader error: $code" ); - } - - /** - * @return mixed - */ - function getErrorCode() { - return $this->errorCode; - } -} |