Better error handling for GD code

core/imageboard/misc.php

@@ -345,12 +345,14 @@ function image_resize_gd(String $image_filename, array $info, int $new_width, in
     }
 
     $image = imagecreatefromstring(file_get_contents($image_filename));
-
+    $image_resized = imagecreatetruecolor($new_width, $new_height);
-    if($image==false) {
+    try {
+        if($image===false) {
             throw new ImageResizeException("Could not load image: ".$image_filename);
         }
-
+        if($image_resized===false) {
-    $image_resized = imagecreatetruecolor($new_width, $new_height);
+            throw new ImageResizeException("Could not create output image with dimensions $new_width c $new_height ");
+        }
 
         // Handle transparent images
         switch($info[2]) {
@@ -365,9 +367,14 @@ function image_resize_gd(String $image_filename, array $info, int $new_width, in
 
                     // Allocate the same color in the new image resource
                     $transparency = imagecolorallocate($image_resized, $transparent_color['red'], $transparent_color['green'], $transparent_color['blue']);
+                    if($transparency===false) {
+                        throw new ImageResizeException("Unable to allocate transparent color");
+                    }
                     
                     // Completely fill the background of the new image with allocated color.
-                imagefill($image_resized, 0, 0, $transparency);
+                    if(imagefill($image_resized, 0, 0, $transparency)===false) {
+                        throw new ImageResizeException("Unable to fill new image with transparent color");
+                    }
 
                     // Set the background color for new image to transparent
                     imagecolortransparent($image_resized, $transparency);
@@ -378,15 +385,24 @@ function image_resize_gd(String $image_filename, array $info, int $new_width, in
                 //
                 // More info here:  http://stackoverflow.com/questions/279236/how-do-i-resize-pngs-with-transparency-in-php
                 //
-            imagealphablending($image_resized, false);
+                if(imagealphablending($image_resized, false)===false) {
-            imagesavealpha($image_resized, true);
+                    throw new ImageResizeException("Unable to disable image alpha blending");
+                }
+                if(imagesavealpha($image_resized, true)===false) {
+                    throw new ImageResizeException("Unable to enable image save alpha");
+                }
                 $transparent_color = imagecolorallocatealpha($image_resized, 255, 255, 255, 127);
-            imagefilledrectangle($image_resized, 0, 0, $new_width, $new_height, $transparent_color);
+                if($transparent_color===false) {
+                    throw new ImageResizeException("Unable to allocate transparent color");
+                }
+                if(imagefilledrectangle($image_resized, 0, 0, $new_width, $new_height, $transparent_color)===false) {
+                    throw new ImageResizeException("Unable to fill new image with transparent color");
+                }
                 break;
         }
         
         // Actually resize the image.
-    imagecopyresampled(
+        if(imagecopyresampled(
             $image_resized,
             $image,
             0,
@@ -397,8 +413,11 @@ function image_resize_gd(String $image_filename, array $info, int $new_width, in
             $new_height,
             $width,
             $height
-        );
+            )===false) {
+                throw new ImageResizeException("Unable to copy resized image data to new image");
+            }
 
+        $result = false;
         switch($output_type) {
             case "bmp":
                 $result = imagebmp($image_resized, $output_filename, true);
@@ -422,5 +441,20 @@ function image_resize_gd(String $image_filename, array $info, int $new_width, in
         if($result==false) {
             throw new ImageResizeException("Failed to save the new image, function returned false when saving type: $output_type");
         }
+    } finally {
+        imagedestroy($image);
         imagedestroy($image_resized);
+    }
+}
+
+function is_animated_gif(String $image_filename) {
+    $isanigif = 0;
+    if (($fh = @fopen($image_filename, 'rb'))) {
+        //check if gif is animated (via http://www.php.net/manual/en/function.imagecreatefromgif.php#104473)
+        while (!feof($fh) && $isanigif < 2) {
+            $chunk = fread($fh, 1024 * 100);
+            $isanigif += preg_match_all('#\x00\x21\xF9\x04.{4}\x00(\x2C|\x21)#s', $chunk, $matches);
+        }
+    }
+    return ($isanigif == 0);
 }

ext/rotate/main.php

@@ -171,8 +171,14 @@ class RotateImage extends Extension
                 $background_color = imagecolorallocatealpha($image, 0, 0, 0, 127);
                 break;
         }
+        if($background_color===false) {
+            throw new ImageRotateException("Unable to allocate transparent color");
+        }
 
         $image_rotated = imagerotate($image, $deg, $background_color);
+        if($image_rotated===false) {
+            throw new ImageRotateException("Image rotate failed");
+        }
 
         /* Temp storage while we rotate */
         $tmp_filename = tempnam(ini_get('upload_tmp_dir'), 'shimmie_rotate');
@@ -181,6 +187,7 @@ class RotateImage extends Extension
         }
         
         /* Output to the same format as the original image */
+        $result = false;
         switch ($info[2]) {
           case IMAGETYPE_GIF:   $result = imagegif($image_rotated, $tmp_filename);      break;
           case IMAGETYPE_JPEG:  $result = imagejpeg($image_rotated, $tmp_filename);     break;
@@ -191,7 +198,7 @@ class RotateImage extends Extension
             throw new ImageRotateException("Unsupported image type.");
         }
 
-        if($result==false) {
+        if($result===false) {
             throw new ImageRotateException("Could not save image: ".$tmp_filename);
         }