1From ffd5a46f68710e2781899d0be4d701429a5a817d Mon Sep 17 00:00:00 2001
2From: Daniel Axtens <dja@axtens.net>
3Date: Mon, 18 Jan 2021 14:51:11 +1100
4Subject: [PATCH] fs/jfs: Do not move to leaf level if name length is negative
5
6Fuzzing JFS revealed crashes where a negative number would be passed
7to le_to_cpu16_copy(). There it would be cast to a large positive number
8and the copy would read and write off the end of the respective buffers.
9
10Catch this at the top as well as the bottom of the loop.
11
12Signed-off-by: Daniel Axtens <dja@axtens.net>
13Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
14Signed-off-by: Stefan Sørensen <stefan.sorensen@spectralink.com>
15---
16 grub-core/fs/jfs.c | 2 +-
17 1 file changed, 1 insertion(+), 1 deletion(-)
18
19diff --git a/grub-core/fs/jfs.c b/grub-core/fs/jfs.c
20index d5a6d65..e5bbda6 100644
21--- a/grub-core/fs/jfs.c
22+++ b/grub-core/fs/jfs.c
23@@ -567,7 +567,7 @@ grub_jfs_getent (struct grub_jfs_diropen *diro)
24
25   /* Move down to the leaf level.  */
26   nextent = leaf->next;
27-  if (leaf->next != 255)
28+  if (leaf->next != 255 && len > 0)
29     do
30       {
31  	next_leaf = &diro->next_leaf[nextent];
32--
332.14.2
34
35