File 0002-video-readers-jpeg-Test-for-an-invalid-nex... of Package grub2

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File 0002-video-readers-jpeg-Test-for-an-invalid-next-marker-r.patch of Package grub2 (Revision 6e0516cb27ba6378e5f4305fb4af311e)

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From 3693b9ddb0e553b3ae1322b5e0ecf9f21453fe46 Mon Sep 17 00:00:00 2001
From: Darren Kenny <darren.kenny@oracle.com>
Date: Fri, 4 Dec 2020 15:39:00 +0000
Subject: [PATCH 02/37] video/readers/jpeg: Test for an invalid next marker
 reference from a jpeg file

While it may never happen, and potentially could be caught at the end of
the function, it is worth checking up front for a bad reference to the
next marker just in case of a maliciously crafted file being provided.

Fixes: CID 73694

Signed-off-by: Darren Kenny <darren.kenny@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
 grub-core/video/readers/jpeg.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/grub-core/video/readers/jpeg.c b/grub-core/video/readers/jpeg.c
index 31359a4c9c..0b6ce3cee6 100644
--- a/grub-core/video/readers/jpeg.c
+++ b/grub-core/video/readers/jpeg.c
@@ -253,6 +253,12 @@ grub_jpeg_decode_quan_table (struct grub_jpeg_data *data)
   next_marker = data->file->offset;
   next_marker += grub_jpeg_get_word (data);
 
+  if (next_marker > data->file->size)
+    {
+      /* Should never be set beyond the size of the file. */
+      return grub_error (GRUB_ERR_BAD_FILE_TYPE, "jpeg: invalid next reference");
+    }
+
   while (data->file->offset + sizeof (data->quan_table[id]) + 1
 	 <= next_marker)
     {
-- 
2.34.1

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File 0002-video-readers-jpeg-Test-for-an-invalid-next-marker-r.patch of Package grub2 (Revision 6e0516cb27ba6378e5f4305fb4af311e)

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