From: Tim Starling <tstarling@users.mediawiki.org>
Date: Fri, 23 Apr 2010 16:24:54 +0000 (+0000)
Subject: More rigorous fix for ImageMagick parameter interpretation (bug 23148 etc.) based... 
X-Git-Tag: 1.31.0-rc.0~37033
X-Git-Url: http://git.cyclocoop.org/%7B%24www_url%7Dadmin/compta/operations/?a=commitdiff_plain;h=41a4e0ea85597495c6f34c8d4f35b96abae97ee7;p=lhc%2Fweb%2Fwiklou.git

More rigorous fix for ImageMagick parameter interpretation (bug 23148 etc.) based on examination of the source code, updating r64932. The source was large and complex and I might have missed some bits, but this is my best guess for now.

Tested bug 23148 and wildcards in filenames (was broken) using a patched convert. With a manual unit test (no convert), tested all branches of the new functions except wfIsWindows() == true.
---

diff --git a/includes/media/Bitmap.php b/includes/media/Bitmap.php
index aada9c5b99..d34f125ec2 100644
--- a/includes/media/Bitmap.php
+++ b/includes/media/Bitmap.php
@@ -62,7 +62,7 @@ class BitmapHandler extends ImageHandler {
 		$physicalHeight = $params['physicalHeight'];
 		$clientWidth = $params['width'];
 		$clientHeight = $params['height'];
-		$descriptionUrl = isset( $params['descriptionUrl'] ) ? "File source: ". $params['descriptionUrl'] : '';
+		$comment = isset( $params['descriptionUrl'] ) ? "File source: ". $params['descriptionUrl'] : '';
 		$srcWidth = $image->getWidth();
 		$srcHeight = $image->getHeight();
 		$mimeType = $image->getMimeType();
@@ -113,7 +113,7 @@ class BitmapHandler extends ImageHandler {
 
 			$quality = '';
 			$sharpen = '';
-			$frame = '';
+			$scene = false;
 			$animation = '';
 			if ( $mimeType == 'image/jpeg' ) {
 				$quality = "-quality 80"; // 80%
@@ -127,7 +127,7 @@ class BitmapHandler extends ImageHandler {
 				if( $this->getImageArea( $image, $srcWidth, $srcHeight ) > $wgMaxAnimatedGifArea ) {
 					// Extract initial frame only; we're so big it'll
 					// be a total drag. :P
-					$frame = '[0]';
+					$scene = 0;
 				} else {
 					// Coalesce is needed to scale animated GIFs properly (bug 1017).
 					$animation = ' -coalesce ';
@@ -151,18 +151,16 @@ class BitmapHandler extends ImageHandler {
 				$tempEnv .
 				wfEscapeShellArg( $wgImageMagickConvertCommand ) .
 				" {$quality} -background white -size {$physicalWidth} ".
-				wfEscapeShellArg( $srcPath . $frame ) .
+				wfEscapeShellArg( $this->escapeMagickInput( $srcPath, $scene ) ) .
 				$animation .
 				// For the -resize option a "!" is needed to force exact size,
 				// or ImageMagick may decide your ratio is wrong and slice off
 				// a pixel.
 				" -thumbnail " . wfEscapeShellArg( "{$physicalWidth}x{$physicalHeight}!" ) .
-				// Add the source url as a comment to the thumb. A % is an 
-				// escape character in ImageMagick, so needs escaping (bug 23148)
-				// http://www.imagemagick.org/script/escape.php?ImageMagick=i766ho1om315scce8eh75efjc6
-				" -set comment " . wfEscapeShellArg( str_replace( '%', '%%', $descriptionUrl ) ) .
+				// Add the source url as a comment to the thumb.	
+				" -set comment " . wfEscapeShellArg( $this->escapeMagickProperty( $comment ) ) .
 				" -depth 8 $sharpen " .
-				wfEscapeShellArg( $dstPath ) . " 2>&1";
+				wfEscapeShellArg( $this->escapeMagickOutput( $dstPath ) ) . " 2>&1";
 			wfDebug( __METHOD__.": running ImageMagick: $cmd\n" );
 			wfProfileIn( 'convert' );
 			$err = wfShellExec( $cmd, $retval );
@@ -254,6 +252,90 @@ class BitmapHandler extends ImageHandler {
 		}
 	}
 
+	/**
+	 * Escape a string for ImageMagick's property input (e.g. -set -comment)
+	 * See InterpretImageProperties() in magick/property.c
+	 */
+	function escapeMagickProperty( $s ) {
+		// Double the backslashes
+		$s = str_replace( '\\', '\\\\', $s );
+		// Double the percents
+		$s = str_replace( '%', '%%', $s );
+		// Escape initial - or @
+		if ( strlen( $s ) > 0 && ( $s[0] === '-' || $s[0] === '@' ) ) {
+			$s = '\\' . $s;
+		}
+		return $s;
+	}
+
+	/**
+	 * Escape a string for ImageMagick's input filenames. See ExpandFilenames() 
+	 * and GetPathComponent() in magick/utility.c.
+	 *
+	 * This won't work with an initial ~ or @, so input files should be prefixed
+	 * with the directory name. 
+	 *
+	 * Glob character unescaping is broken in ImageMagick before 6.6.1-5, but
+	 * it's broken in a way that doesn't involve trying to convert every file 
+	 * in a directory, so we're better off escaping and waiting for the bugfix
+	 * to filter down to users.
+	 *
+	 * @param $path string The file path
+	 * @param $scene string The scene specification, or false if there is none
+	 */
+	function escapeMagickInput( $path, $scene = false ) {
+		# Die on initial metacharacters (caller should prepend path)
+		$firstChar = substr( $path, 0, 1 );
+		if ( $firstChar === '~' || $firstChar === '@' ) {
+			throw new MWException( __METHOD__.': cannot escape this path name' );
+		}
+
+		# Escape glob chars
+		$path = preg_replace( '/[*?\[\]{}]/', '\\\\\0', $path );
+
+		return $this->escapeMagickPath( $path, $scene );
+	}
+
+	/**
+	 * Escape a string for ImageMagick's output filename. See 
+	 * InterpretImageFilename() in magick/image.c.
+	 */
+	function escapeMagickOutput( $path, $scene = false ) {
+		$path = str_replace( '%', '%%', $path );
+		return $this->escapeMagickPath( $path, $scene );
+	}
+
+	/**
+	 * Armour a string against ImageMagick's GetPathComponent(). This is a 
+	 * helper function for escapeMagickInput() and escapeMagickOutput().
+	 *
+	 * @param $path string The file path
+	 * @param $scene string The scene specification, or false if there is none
+	 */
+	protected function escapeMagickPath( $path, $scene = false ) {
+		# Die on format specifiers (other than drive letters). The regex is
+		# meant to match all the formats you get from "convert -list format"
+		if ( preg_match( '/^([a-zA-Z0-9-]+):/', $path, $m ) ) {
+			if ( wfIsWindows() && is_dir( $m[0] ) ) {
+				// OK, it's a drive letter
+				// ImageMagick has a similar exception, see IsMagickConflict()
+			} else {
+				throw new MWException( __METHOD__.': unexpected colon character in path name' );
+			}
+		}
+
+		# If there are square brackets, add a do-nothing scene specification 
+		# to force a literal interpretation
+		if ( $scene === false ) {
+			if ( strpos( $path, '[' ) !== false ) {
+				$path .= '[0--1]';
+			}
+		} else {
+			$path .= "[$scene]";
+		}
+		return $path;
+	}
+
 	static function imageJpegWrapper( $dst_image, $thumbPath ) {
 		imageinterlace( $dst_image );
 		imagejpeg( $dst_image, $thumbPath, 95 );