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See Release Notes

  • Bug fixes for general core bugs in 4.2.x will end 22 April 2024 (12 months).
  • Bug fixes for security issues in 4.2.x will end 7 October 2024 (18 months).
  • PHP version: minimum PHP 8.0.0 Note: minimum PHP version has increased since Moodle 4.1. PHP 8.1.x is supported too.
<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle 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 3 of the License, or
// (at your option) any later version.
//
// Moodle 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 Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**
 * Implementation of zip file archive.
 *
 * @package   core_files
 * @copyright 2008 Petr Skoda (http://skodak.org)
 * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

defined('MOODLE_INTERNAL') || die();

require_once("$CFG->libdir/filestorage/file_archive.php");

/**
 * Zip file archive class.
 *
 * @package   core_files
 * @category  files
 * @copyright 2008 Petr Skoda (http://skodak.org)
 * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */
class zip_archive extends file_archive {

    /** @var string Pathname of archive */
    protected $archivepathname = null;

    /** @var int archive open mode */
    protected $mode = null;

    /** @var int Used memory tracking */
    protected $usedmem = 0;

    /** @var int Iteration position */
    protected $pos = 0;

    /** @var ZipArchive instance */
    protected $za;

    /** @var bool was this archive modified? */
    protected $modified = false;

    /** @var array unicode decoding array, created by decoding zip file */
    protected $namelookup = null;

    /** @var string base64 encoded contents of empty zip file */
    protected static $emptyzipcontent = 'UEsFBgAAAAAAAAAAAAAAAAAAAAAAAA==';

    /** @var bool ugly hack for broken empty zip handling in < PHP 5.3.10 */
    protected $emptyziphack = false;

    /**
     * Create new zip_archive instance.
     */
    public function __construct() {
        $this->encoding = null; // Autodetects encoding by default.
    }

    /**
     * Open or create archive (depending on $mode).
     *
     * @todo MDL-31048 return error message
     * @param string $archivepathname
     * @param int $mode OPEN, CREATE or OVERWRITE constant
     * @param string $encoding archive local paths encoding, empty means autodetect
     * @return bool success
     */
    public function open($archivepathname, $mode=file_archive::CREATE, $encoding=null) {
        $this->close();

        $this->usedmem  = 0;
        $this->pos      = 0;
        $this->encoding = $encoding;
        $this->mode     = $mode;

        $this->za = new ZipArchive();

        switch($mode) {
            case file_archive::OPEN:      $flags = 0; break;
            case file_archive::OVERWRITE: $flags = ZIPARCHIVE::CREATE | ZIPARCHIVE::OVERWRITE; break; //changed in PHP 5.2.8
            case file_archive::CREATE:
            default :                     $flags = ZIPARCHIVE::CREATE; break;
        }

        $result = $this->za->open($archivepathname, $flags);

        if ($flags == 0 and $result === ZIPARCHIVE::ER_NOZIP and filesize($archivepathname) === 22) {
            // Legacy PHP versions < 5.3.10 can not deal with empty zip archives.
            if (file_get_contents($archivepathname) === base64_decode(self::$emptyzipcontent)) {
                if ($temp = make_temp_directory('zip')) {
                    $this->emptyziphack = tempnam($temp, 'zip');
                    $this->za = new ZipArchive();
                    $result = $this->za->open($this->emptyziphack, ZIPARCHIVE::CREATE);
                }
            }
        }

        if ($result === true) {
            if (file_exists($archivepathname)) {
                $this->archivepathname = realpath($archivepathname);
            } else {
                $this->archivepathname = $archivepathname;
            }
            return true;

        } else {
            $message = 'Unknown error.';
            switch ($result) {
                case ZIPARCHIVE::ER_EXISTS: $message = 'File already exists.'; break;
                case ZIPARCHIVE::ER_INCONS: $message = 'Zip archive inconsistent.'; break;
                case ZIPARCHIVE::ER_INVAL: $message = 'Invalid argument.'; break;
                case ZIPARCHIVE::ER_MEMORY: $message = 'Malloc failure.'; break;
                case ZIPARCHIVE::ER_NOENT: $message = 'No such file.'; break;
                case ZIPARCHIVE::ER_NOZIP: $message = 'Not a zip archive.'; break;
                case ZIPARCHIVE::ER_OPEN: $message = 'Can\'t open file.'; break;
                case ZIPARCHIVE::ER_READ: $message = 'Read error.'; break;
                case ZIPARCHIVE::ER_SEEK: $message = 'Seek error.'; break;
            }
            debugging($message.': '.$archivepathname, DEBUG_DEVELOPER);
            $this->za = null;
            $this->archivepathname = null;
            return false;
        }
    }

    /**
     * Normalize $localname, always keep in utf-8 encoding.
     *
     * @param string $localname name of file in utf-8 encoding
     * @return string normalised compressed file or directory name
     */
    protected function mangle_pathname($localname) {
        $result = str_replace('\\', '/', $localname);   // no MS \ separators
        $result = preg_replace('/\.\.+\//', '', $result); // Cleanup any potential ../ transversal (any number of dots).
        $result = preg_replace('/\.\.+/', '.', $result); // Join together any number of consecutive dots.
        $result = ltrim($result, '/');                  // no leading slash

        if ($result === '.') {
            $result = '';
        }

        return $result;
    }

    /**
     * Tries to convert $localname into utf-8
     * please note that it may fail really badly.
     * The resulting file name is cleaned.
     *
     * @param string $localname name (encoding is read from zip file or guessed)
     * @return string in utf-8
     */
    protected function unmangle_pathname($localname) {
        $this->init_namelookup();

        if (!isset($this->namelookup[$localname])) {
            $name = $localname;
            // This should not happen.
            if (!empty($this->encoding) and $this->encoding !== 'utf-8') {
                $name = @core_text::convert($name, $this->encoding, 'utf-8');
            }
            $name = str_replace('\\', '/', $name);   // no MS \ separators
            $name = clean_param($name, PARAM_PATH);  // only safe chars
            return ltrim($name, '/');                // no leading slash
        }

        return $this->namelookup[$localname];
    }

    /**
     * Close archive, write changes to disk.
     *
     * @return bool success
     */
    public function close() {
        if (!isset($this->za)) {
            return false;
        }

        if ($this->emptyziphack) {
            @$this->za->close();
            $this->za = null;
            $this->mode = null;
            $this->namelookup = null;
            $this->modified = false;
            @unlink($this->emptyziphack);
            $this->emptyziphack = false;
            return true;

        } else if ($this->za->numFiles == 0) {
            // PHP can not create empty archives, so let's fake it.
            @$this->za->close();
            $this->za = null;
            $this->mode = null;
            $this->namelookup = null;
            $this->modified = false;
            // If the existing archive is already empty, we didn't change it.  Don't bother completing a save.
            // This is important when we are inspecting archives that we might not have write permission to.
            if (@filesize($this->archivepathname) == 22 &&
                    @file_get_contents($this->archivepathname) === base64_decode(self::$emptyzipcontent)) {
                return true;
            }
            @unlink($this->archivepathname);
            $data = base64_decode(self::$emptyzipcontent);
            if (!file_put_contents($this->archivepathname, $data)) {
                return false;
            }
            return true;
        }

        $res = $this->za->close();
        $this->za = null;
        $this->mode = null;
        $this->namelookup = null;

        if ($this->modified) {
            $this->fix_utf8_flags();
            $this->modified = false;
        }

        return $res;
    }

    /**
     * Returns file stream for reading of content.
     *
     * @param int $index index of file
     * @return resource|bool file handle or false if error
     */
    public function get_stream($index) {
        if (!isset($this->za)) {
            return false;
        }

        $name = $this->za->getNameIndex($index);
        if ($name === false) {
            return false;
        }

        return $this->za->getStream($name);
    }

    /**
     * Extract the archive contents to the given location.
     *
     * @param string $destination Path to the location where to extract the files.
     * @param int $index Index of the archive entry.
     * @return bool true on success or false on failure
     */
    public function extract_to($destination, $index) {

        if (!isset($this->za)) {
            return false;
        }

        $name = $this->za->getNameIndex($index);

        if ($name === false) {
            return false;
        }

        return $this->za->extractTo($destination, $name);
    }

    /**
     * Returns file information.
     *
     * @param int $index index of file
     * @return stdClass|bool info object or false if error
     */
    public function get_info($index) {
        if (!isset($this->za)) {
            return false;
        }

        // Need to use the ZipArchive's numfiles, as $this->count() relies on this function to count actual files (skipping OSX junk).
        if ($index < 0 or $index >=$this->za->numFiles) {
            return false;
        }

        // PHP 5.6 introduced encoding guessing logic for file names. To keep consistent behaviour with older versions,
        // we fall back to obtaining file names as raw unmodified strings.
        $result = $this->za->statIndex($index, ZipArchive::FL_ENC_RAW);

        if ($result === false) {
            return false;
        }

        $info = new stdClass();
        $info->index             = $index;
        $info->original_pathname = $result['name'];
        $info->pathname          = $this->unmangle_pathname($result['name']);
        $info->mtime             = (int)$result['mtime'];

        if ($info->pathname[strlen($info->pathname)-1] === '/') {
            $info->is_directory = true;
            $info->size         = 0;
        } else {
            $info->is_directory = false;
            $info->size         = (int)$result['size'];
        }

        if ($this->is_system_file($info)) {
            // Don't return system files.
            return false;
        }

        return $info;
    }

    /**
     * Returns array of info about all files in archive.
     *
     * @return array of file infos
     */
    public function list_files() {
        if (!isset($this->za)) {
            return false;
        }

        $infos = array();

        foreach ($this as $info) {
            // Simply iterating over $this will give us info only for files we're interested in.
            array_push($infos, $info);
        }

        return $infos;
    }

    public function is_system_file($fileinfo) {
        if (substr($fileinfo->pathname, 0, 8) === '__MACOSX' or substr($fileinfo->pathname, -9) === '.DS_Store') {
            // Mac OSX system files.
            return true;
        }
        if (substr($fileinfo->pathname, -9) === 'Thumbs.db') {
            $stream = $this->za->getStream($fileinfo->pathname);
            $info = base64_encode(fread($stream, 8));
            fclose($stream);
            if ($info === '0M8R4KGxGuE=') {
                // It's an OLE Compound File - so it's almost certainly a Windows thumbnail cache.
                return true;
            }
        }
        return false;
    }

    /**
     * Returns number of files in archive.
     *
     * @return int number of files
     */
< public function count() {
> public function count(): int {
if (!isset($this->za)) { return false; } return count($this->list_files()); } /** * Returns approximate number of files in archive. This may be a slight * overestimate. * * @return int|bool Estimated number of files, or false if not opened */ public function estimated_count() { if (!isset($this->za)) { return false; } return $this->za->numFiles; } /** * Add file into archive. * * @param string $localname name of file in archive * @param string $pathname location of file * @return bool success */ public function add_file_from_pathname($localname, $pathname) { if ($this->emptyziphack) { $this->close(); $this->open($this->archivepathname, file_archive::OVERWRITE, $this->encoding); } if (!isset($this->za)) { return false; } if ($this->archivepathname === realpath($pathname)) { // Do not add self into archive. return false; } if (!is_readable($pathname) or is_dir($pathname)) { return false; } if (is_null($localname)) { $localname = clean_param($pathname, PARAM_PATH); } $localname = trim($localname, '/'); // No leading slashes in archives! $localname = $this->mangle_pathname($localname); if ($localname === '') { // Sorry - conversion failed badly. return false; } if (!$this->za->addFile($pathname, $localname)) { return false; } $this->modified = true; return true; } /** * Add content of string into archive. * * @param string $localname name of file in archive * @param string $contents contents * @return bool success */ public function add_file_from_string($localname, $contents) { if ($this->emptyziphack) { $this->close(); $this->open($this->archivepathname, file_archive::OVERWRITE, $this->encoding); } if (!isset($this->za)) { return false; } $localname = trim($localname, '/'); // No leading slashes in archives! $localname = $this->mangle_pathname($localname); if ($localname === '') { // Sorry - conversion failed badly. return false; } if ($this->usedmem > 2097151) { // This prevents running out of memory when adding many large files using strings. $this->close(); $res = $this->open($this->archivepathname, file_archive::OPEN, $this->encoding); if ($res !== true) {
< print_error('cannotopenzip');
> throw new \moodle_exception('cannotopenzip');
} } $this->usedmem += strlen($contents); if (!$this->za->addFromString($localname, $contents)) { return false; } $this->modified = true; return true; } /** * Add empty directory into archive. * * @param string $localname name of file in archive * @return bool success */ public function add_directory($localname) { if ($this->emptyziphack) { $this->close(); $this->open($this->archivepathname, file_archive::OVERWRITE, $this->encoding); } if (!isset($this->za)) { return false; } $localname = trim($localname, '/'). '/'; $localname = $this->mangle_pathname($localname); if ($localname === '/') { // Sorry - conversion failed badly. return false; } if ($localname !== '') { if (!$this->za->addEmptyDir($localname)) { return false; } $this->modified = true; } return true; } /** * Returns current file info. * * @return stdClass */
> #[\ReturnTypeWillChange]
public function current() { if (!isset($this->za)) { return false; } return $this->get_info($this->pos); } /** * Returns the index of current file. * * @return int current file index */
> #[\ReturnTypeWillChange]
public function key() { return $this->pos; } /** * Moves forward to next file. */
< public function next() {
> public function next(): void {
$this->pos++; } /** * Rewinds back to the first file. */
< public function rewind() {
> public function rewind(): void {
$this->pos = 0; } /** * Did we reach the end? * * @return bool */
< public function valid() {
> public function valid(): bool {
if (!isset($this->za)) { return false; } // Skip over unwanted system files (get_info will return false). while (!$this->get_info($this->pos) && $this->pos < $this->za->numFiles) { $this->next(); } // No files left - we're at the end. if ($this->pos >= $this->za->numFiles) { return false; } return true; } /** * Create a map of file names used in zip archive. * @return void */ protected function init_namelookup() { if ($this->emptyziphack) { $this->namelookup = array(); return; } if (!isset($this->za)) { return; } if (isset($this->namelookup)) { return; } $this->namelookup = array(); if ($this->mode != file_archive::OPEN) { // No need to tweak existing names when creating zip file because there are none yet! return; } if (!file_exists($this->archivepathname)) { return; } if (!$fp = fopen($this->archivepathname, 'rb')) { return; } if (!$filesize = filesize($this->archivepathname)) { return; } $centralend = self::zip_get_central_end($fp, $filesize); if ($centralend === false or $centralend['disk'] !== 0 or $centralend['disk_start'] !== 0 or $centralend['offset'] === 0xFFFFFFFF) { // Single disk archives only and o support for ZIP64, sorry. fclose($fp); return; } fseek($fp, $centralend['offset']); $data = fread($fp, $centralend['size']); $pos = 0; $files = array(); for($i=0; $i<$centralend['entries']; $i++) { $file = self::zip_parse_file_header($data, $centralend, $pos); if ($file === false) { // Wrong header, sorry. fclose($fp); return; } $files[] = $file; } fclose($fp); foreach ($files as $file) { $name = $file['name']; if (preg_match('/^[a-zA-Z0-9_\-\.]*$/', $file['name'])) { // No need to fix ASCII. $name = fix_utf8($name); } else if (!($file['general'] & pow(2, 11))) { // First look for unicode name alternatives. $found = false; foreach($file['extra'] as $extra) { if ($extra['id'] === 0x7075) { $data = unpack('cversion/Vcrc', substr($extra['data'], 0, 5)); if ($data['crc'] === crc32($name)) { $found = true; $name = substr($extra['data'], 5); } } } if (!$found and !empty($this->encoding) and $this->encoding !== 'utf-8') { // Try the encoding from open(). $newname = @core_text::convert($name, $this->encoding, 'utf-8'); $original = core_text::convert($newname, 'utf-8', $this->encoding); if ($original === $name) { $found = true; $name = $newname; } } if (!$found and $file['version'] === 0x315) { // This looks like OS X build in zipper. $newname = fix_utf8($name); if ($newname === $name) { $found = true; $name = $newname; } } if (!$found and $file['version'] === 0) { // This looks like our old borked Moodle 2.2 file. $newname = fix_utf8($name); if ($newname === $name) { $found = true; $name = $newname; } } if (!$found and $encoding = get_string('oldcharset', 'langconfig')) { // Last attempt - try the dos/unix encoding from current language. $windows = true; foreach($file['extra'] as $extra) { // In Windows archivers do not usually set any extras with the exception of NTFS flag in WinZip/WinRar. $windows = false; if ($extra['id'] === 0x000a) { $windows = true; break; } } if ($windows === true) { switch(strtoupper($encoding)) { case 'ISO-8859-1': $encoding = 'CP850'; break; case 'ISO-8859-2': $encoding = 'CP852'; break; case 'ISO-8859-4': $encoding = 'CP775'; break; case 'ISO-8859-5': $encoding = 'CP866'; break; case 'ISO-8859-6': $encoding = 'CP720'; break; case 'ISO-8859-7': $encoding = 'CP737'; break; case 'ISO-8859-8': $encoding = 'CP862'; break; case 'WINDOWS-1251': $encoding = 'CP866'; break; case 'EUC-JP': case 'UTF-8': if ($winchar = get_string('localewincharset', 'langconfig')) { // Most probably works only for zh_cn, // if there are more problems we could add zipcharset to langconfig files. $encoding = $winchar; } break; } } $newname = @core_text::convert($name, $encoding, 'utf-8'); $original = core_text::convert($newname, 'utf-8', $encoding); if ($original === $name) { $name = $newname; } } } $name = str_replace('\\', '/', $name); // no MS \ separators $name = clean_param($name, PARAM_PATH); // only safe chars $name = ltrim($name, '/'); // no leading slash if (function_exists('normalizer_normalize')) { $name = normalizer_normalize($name, Normalizer::FORM_C); } $this->namelookup[$file['name']] = $name; } } /** * Add unicode flag to all files in archive. * * NOTE: single disk archives only, no ZIP64 support. * * @return bool success, modifies the file contents */ protected function fix_utf8_flags() { if ($this->emptyziphack) { return true; } if (!file_exists($this->archivepathname)) { return true; } // Note: the ZIP structure is described at http://www.pkware.com/documents/casestudies/APPNOTE.TXT if (!$fp = fopen($this->archivepathname, 'rb+')) { return false; } if (!$filesize = filesize($this->archivepathname)) { return false; } $centralend = self::zip_get_central_end($fp, $filesize); if ($centralend === false or $centralend['disk'] !== 0 or $centralend['disk_start'] !== 0 or $centralend['offset'] === 0xFFFFFFFF) { // Single disk archives only and o support for ZIP64, sorry. fclose($fp); return false; } fseek($fp, $centralend['offset']); $data = fread($fp, $centralend['size']); $pos = 0; $files = array(); for($i=0; $i<$centralend['entries']; $i++) { $file = self::zip_parse_file_header($data, $centralend, $pos); if ($file === false) { // Wrong header, sorry. fclose($fp); return false; } $newgeneral = $file['general'] | pow(2, 11); if ($newgeneral === $file['general']) { // Nothing to do with this file. continue; } if (preg_match('/^[a-zA-Z0-9_\-\.]*$/', $file['name'])) { // ASCII file names are always ok. continue; } if ($file['extra']) { // Most probably not created by php zip ext, better to skip it. continue; } if (fix_utf8($file['name']) !== $file['name']) { // Does not look like a valid utf-8 encoded file name, skip it. continue; } // Read local file header. fseek($fp, $file['local_offset']); $localfile = unpack('Vsig/vversion_req/vgeneral/vmethod/vmtime/vmdate/Vcrc/Vsize_compressed/Vsize/vname_length/vextra_length', fread($fp, 30)); if ($localfile['sig'] !== 0x04034b50) { // Borked file! fclose($fp); return false; } $file['local'] = $localfile; $files[] = $file; } foreach ($files as $file) { $localfile = $file['local']; // Add the unicode flag in central file header. fseek($fp, $file['central_offset'] + 8); if (ftell($fp) === $file['central_offset'] + 8) { $newgeneral = $file['general'] | pow(2, 11); fwrite($fp, pack('v', $newgeneral)); } // Modify local file header too. fseek($fp, $file['local_offset'] + 6); if (ftell($fp) === $file['local_offset'] + 6) { $newgeneral = $localfile['general'] | pow(2, 11); fwrite($fp, pack('v', $newgeneral)); } } fclose($fp); return true; } /** * Read end of central signature of ZIP file. * @internal * @static * @param resource $fp * @param int $filesize * @return array|bool */ public static function zip_get_central_end($fp, $filesize) { // Find end of central directory record. fseek($fp, $filesize - 22); $info = unpack('Vsig', fread($fp, 4)); if ($info['sig'] === 0x06054b50) { // There is no comment. fseek($fp, $filesize - 22); $data = fread($fp, 22); } else { // There is some comment with 0xFF max size - that is 65557. fseek($fp, $filesize - 65557); $data = fread($fp, 65557); } $pos = strpos($data, pack('V', 0x06054b50)); if ($pos === false) { // Borked ZIP structure! return false; } $centralend = unpack('Vsig/vdisk/vdisk_start/vdisk_entries/ventries/Vsize/Voffset/vcomment_length', substr($data, $pos, 22)); if ($centralend['comment_length']) { $centralend['comment'] = substr($data, 22, $centralend['comment_length']); } else { $centralend['comment'] = ''; } return $centralend; } /** * Parse file header. * @internal * @param string $data * @param array $centralend * @param int $pos (modified) * @return array|bool file info */ public static function zip_parse_file_header($data, $centralend, &$pos) { $file = unpack('Vsig/vversion/vversion_req/vgeneral/vmethod/Vmodified/Vcrc/Vsize_compressed/Vsize/vname_length/vextra_length/vcomment_length/vdisk/vattr/Vattrext/Vlocal_offset', substr($data, $pos, 46)); $file['central_offset'] = $centralend['offset'] + $pos; $pos = $pos + 46; if ($file['sig'] !== 0x02014b50) { // Borked ZIP structure! return false; } $file['name'] = substr($data, $pos, $file['name_length']); $pos = $pos + $file['name_length']; $file['extra'] = array(); $file['extra_data'] = ''; if ($file['extra_length']) { $extradata = substr($data, $pos, $file['extra_length']); $file['extra_data'] = $extradata; while (strlen($extradata) > 4) { $extra = unpack('vid/vsize', substr($extradata, 0, 4)); $extra['data'] = substr($extradata, 4, $extra['size']); $extradata = substr($extradata, 4+$extra['size']); $file['extra'][] = $extra; } $pos = $pos + $file['extra_length']; } if ($file['comment_length']) { $pos = $pos + $file['comment_length']; $file['comment'] = substr($data, $pos, $file['comment_length']); } else { $file['comment'] = ''; } return $file; } }