File 0013-video-readers-png-Refuse-to-handle-multiple-image-he.patch of Package grub2.28511

From f8481a53ce767818820cb408667f80dde64532bc Mon Sep 17 00:00:00 2001
From: Daniel Axtens <dja@axtens.net>
Date: Tue, 6 Jul 2021 14:13:40 +1000
Subject: [PATCH 13/37] video/readers/png: Refuse to handle multiple image
 headers

This causes the bitmap to be leaked. Do not permit multiple image headers.

Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
 grub-core/video/readers/png.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/grub-core/video/readers/png.c b/grub-core/video/readers/png.c
index d715c4629f..35ae553c8e 100644
--- a/grub-core/video/readers/png.c
+++ b/grub-core/video/readers/png.c
@@ -258,6 +258,9 @@ grub_png_decode_image_header (struct grub_png_data *data)
   int color_bits;
   enum grub_video_blit_format blt;
 
+  if (data->image_width || data->image_height)
+    return grub_error (GRUB_ERR_BAD_FILE_TYPE, "png: two image headers found");
+
   data->image_width = grub_png_get_dword (data);
   data->image_height = grub_png_get_dword (data);
 
-- 
2.34.1