mediawiki-extensions-PdfHan.../PdfHandler_body.php
Brian Wolff e1d584ec6c SECURITY: Add -dSAFER to ghostscript as a hardening measure
-dSAFER disables certain scary features of ghostscript
(like arbitrary file access). Its primarily about postscript
security, but enable it for pdfs to be safe.

Bug: T136402
Change-Id: I0ab37ddb5d134334e975bc07d3b9ba7bfc7a5659
2016-08-23 04:30:52 +00:00

421 lines
10 KiB
PHP

<?php
/**
* Copyright © 2007 Martin Seidel (Xarax) <jodeldi@gmx.de>
*
* Inspired by djvuhandler from Tim Starling
* Modified and written by Xarax
*
* 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
*/
class PdfHandler extends ImageHandler {
static $messages = array(
'main' => 'pdf-file-page-warning',
'header' => 'pdf-file-page-warning-header',
'info' => 'pdf-file-page-warning-info',
'footer' => 'pdf-file-page-warning-footer',
);
/**
* @return bool
*/
function isEnabled() {
global $wgPdfProcessor, $wgPdfPostProcessor, $wgPdfInfo;
if ( !isset( $wgPdfProcessor ) || !isset( $wgPdfPostProcessor ) || !isset( $wgPdfInfo ) ) {
wfDebug( "PdfHandler is disabled, please set the following\n" );
wfDebug( "variables in LocalSettings.php:\n" );
wfDebug( "\$wgPdfProcessor, \$wgPdfPostProcessor, \$wgPdfInfo\n" );
return false;
}
return true;
}
/**
* @param $file
* @return bool
*/
function mustRender( $file ) {
return true;
}
/**
* @param $file
* @return bool
*/
function isMultiPage( $file ) {
return true;
}
/**
* @param $name
* @param $value
* @return bool
*/
function validateParam( $name, $value ) {
if ( $name === 'page' && trim( $value ) !== (string) intval( $value ) ) {
// Extra junk on the end of page, probably actually a caption
// e.g. [[File:Foo.pdf|thumb|Page 3 of the document shows foo]]
return false;
}
if ( in_array( $name, array( 'width', 'height', 'page' ) ) ) {
return ( $value > 0 );
}
return false;
}
/**
* @param $params array
* @return bool|string
*/
function makeParamString( $params ) {
$page = isset( $params['page'] ) ? $params['page'] : 1;
if ( !isset( $params['width'] ) ) {
return false;
}
return "page{$page}-{$params['width']}px";
}
/**
* @param $str string
* @return array|bool
*/
function parseParamString( $str ) {
$m = false;
if ( preg_match( '/^page(\d+)-(\d+)px$/', $str, $m ) ) {
return array( 'width' => $m[2], 'page' => $m[1] );
}
return false;
}
/**
* @param $params array
* @return array
*/
function getScriptParams( $params ) {
return array(
'width' => $params['width'],
'page' => $params['page'],
);
}
/**
* @return array
*/
function getParamMap() {
return array(
'img_width' => 'width',
'img_page' => 'page',
);
}
/**
* @param $width
* @param $height
* @param $msg
* @return MediaTransformError
*/
protected function doThumbError( $width, $height, $msg ) {
return new MediaTransformError( 'thumbnail_error',
$width, $height, wfMessage( $msg )->inContentLanguage()->text() );
}
/**
* @param $image File
* @param $dstPath string
* @param $dstUrl string
* @param $params array
* @param $flags int
* @return MediaTransformError|MediaTransformOutput|ThumbnailImage|TransformParameterError
*/
function doTransform( $image, $dstPath, $dstUrl, $params, $flags = 0 ) {
global $wgPdfProcessor, $wgPdfPostProcessor, $wgPdfHandlerDpi, $wgPdfHandlerJpegQuality;
$metadata = $image->getMetadata();
if ( !$metadata ) {
return $this->doThumbError(
isset( $params['width'] ) ? $params['width'] : null,
isset( $params['height'] ) ? $params['height'] : null,
'pdf_no_metadata'
);
}
if ( !$this->normaliseParams( $image, $params ) ) {
return new TransformParameterError( $params );
}
$width = (int)$params['width'];
$height = (int)$params['height'];
$page = (int)$params['page'];
if ( $page > $this->pageCount( $image ) ) {
return $this->doThumbError( $width, $height, 'pdf_page_error' );
}
if ( $flags & self::TRANSFORM_LATER ) {
return new ThumbnailImage( $image, $dstUrl, $width, $height, false, $page );
}
if ( !wfMkdirParents( dirname( $dstPath ), null, __METHOD__ ) ) {
return $this->doThumbError( $width, $height, 'thumbnail_dest_directory' );
}
// Thumbnail extraction is very inefficient for large files.
// Provide a way to pool count limit the number of downloaders.
if ( $image->getSize() >= 1e7 ) { // 10MB
$work = new PoolCounterWorkViaCallback( 'GetLocalFileCopy', sha1( $image->getName() ),
array(
'doWork' => function() use ( $image ) {
return $image->getLocalRefPath();
}
)
);
$srcPath = $work->execute();
} else {
$srcPath = $image->getLocalRefPath();
}
if ( $srcPath === false ) { // could not download original
return $this->doThumbError( $width, $height, 'filemissing' );
}
$cmd = '(' . wfEscapeShellArg(
$wgPdfProcessor,
"-sDEVICE=jpeg",
"-sOutputFile=-",
"-dFirstPage={$page}",
"-dLastPage={$page}",
"-dSAFER",
"-r{$wgPdfHandlerDpi}",
"-dBATCH",
"-dNOPAUSE",
"-q",
$srcPath
);
$cmd .= " | " . wfEscapeShellArg(
$wgPdfPostProcessor,
"-depth",
"8",
"-quality",
$wgPdfHandlerJpegQuality,
"-resize",
$width,
"-",
$dstPath
);
$cmd .= ")";
wfProfileIn( 'PdfHandler' );
wfDebug( __METHOD__ . ": $cmd\n" );
$retval = '';
$err = wfShellExecWithStderr( $cmd, $retval );
wfProfileOut( 'PdfHandler' );
$removed = $this->removeBadFile( $dstPath, $retval );
if ( $retval != 0 || $removed ) {
wfDebugLog( 'thumbnail',
sprintf( 'thumbnail failed on %s: error %d "%s" from "%s"',
wfHostname(), $retval, trim( $err ), $cmd ) );
return new MediaTransformError( 'thumbnail_error', $width, $height, $err );
} else {
return new ThumbnailImage( $image, $dstUrl, $width, $height, $dstPath, $page );
}
}
/**
* @param $image File
* @param $path string
* @return PdfImage
*/
function getPdfImage( $image, $path ) {
if ( !$image ) {
$pdfimg = new PdfImage( $path );
} elseif ( !isset( $image->pdfImage ) ) {
$pdfimg = $image->pdfImage = new PdfImage( $path );
} else {
$pdfimg = $image->pdfImage;
}
return $pdfimg;
}
/**
* @param $image File
* @return bool
*/
function getMetaArray( $image ) {
if ( isset( $image->pdfMetaArray ) ) {
return $image->pdfMetaArray;
}
$metadata = $image->getMetadata();
if ( !$this->isMetadataValid( $image, $metadata ) ) {
wfDebug( "Pdf metadata is invalid or missing, should have been fixed in upgradeRow\n" );
return false;
}
$work = new PoolCounterWorkViaCallback( 'PdfHandler-unserialize-metadata', $image->getName(), array(
'doWork' => function() use ( $image, $metadata ) {
wfSuppressWarnings();
$image->pdfMetaArray = unserialize( $metadata );
wfRestoreWarnings();
},
) );
$work->execute();
return $image->pdfMetaArray;
}
/**
* @param $image File
* @param $path string
* @return array|bool
*/
function getImageSize( $image, $path ) {
return $this->getPdfImage( $image, $path )->getImageSize();
}
/**
* @param $ext
* @param $mime string
* @param $params null
* @return array
*/
function getThumbType( $ext, $mime, $params = null ) {
global $wgPdfOutputExtension;
static $mime;
if ( !isset( $mime ) ) {
$magic = MimeMagic::singleton();
$mime = $magic->guessTypesForExtension( $wgPdfOutputExtension );
}
return array( $wgPdfOutputExtension, $mime );
}
/**
* @param $image File
* @param $path string
* @return string
*/
function getMetadata( $image, $path ) {
return serialize( $this->getPdfImage( $image, $path )->retrieveMetaData() );
}
/**
* @param $image File
* @param $metadata string
* @return bool
*/
function isMetadataValid( $image, $metadata ) {
if ( !$metadata || $metadata === serialize(array()) ) {
return self::METADATA_BAD;
} elseif ( strpos( $metadata, 'mergedMetadata' ) === false ) {
return self::METADATA_COMPATIBLE;
}
return self::METADATA_GOOD;
}
/**
* @param $image File
* @param bool|IContextSource $context Context to use (optional)
* @return bool|int
*/
function formatMetadata( $image, $context = false ) {
$meta = $image->getMetadata();
if ( !$meta ) {
return false;
}
wfSuppressWarnings();
$meta = unserialize( $meta );
wfRestoreWarnings();
if ( !isset( $meta['mergedMetadata'] )
|| !is_array( $meta['mergedMetadata'] )
|| count( $meta['mergedMetadata'] ) < 1
) {
return false;
}
// Inherited from MediaHandler.
return $this->formatMetadataHelper( $meta['mergedMetadata'], $context );
}
/**
* @param File $image
* @return bool|int
*/
function pageCount( File $image ) {
$data = $this->getMetaArray( $image );
if ( !$data || !isset( $data['Pages'] ) ) {
return false;
}
return intval( $data['Pages'] );
}
/**
* @param $image File
* @param $page int
* @return array|bool
*/
function getPageDimensions( File $image, $page ) {
$data = $this->getMetaArray( $image );
return PdfImage::getPageSize( $data, $page );
}
/**
* @param $image File
* @param $page int
* @return bool
*/
function getPageText( File $image, $page ) {
$data = $this->getMetaArray( $image, true );
if ( !$data || !isset( $data['text'] ) || !isset( $data['text'][$page - 1] ) ) {
return false;
}
return $data['text'][$page - 1];
}
/**
* Adds a warning about PDFs being potentially dangerous to the file
* page. Multiple messages with this base will be used.
* @param File $file
* @return array
*/
function getWarningConfig( $file ) {
return array(
'messages' => self::$messages,
'link' => '//www.mediawiki.org/wiki/Special:MyLanguage/Help:Security/PDF_files',
'module' => 'pdfhandler.messages',
);
}
/**
* Register a module with the warning messages in it.
* @param &$resourceLoader ResourceLoader
*/
static function registerWarningModule( &$resourceLoader ) {
$resourceLoader->register( 'pdfhandler.messages', array(
'messages' => array_values( self::$messages ),
) );
}
}