More rigorous fix for ImageMagick parameter interpretation (bug 23148 etc.) based...

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 aada9c5..d34f125 100644 (file)
--- 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 );