You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
66 lines
2.0 KiB
66 lines
2.0 KiB
9 months ago
|
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
|
||
|
|
From: Darren Kenny <darren.kenny@oracle.com>
|
||
|
|
Date: Fri, 11 Dec 2020 15:03:13 +0000
|
||
|
|
Subject: [PATCH] kern/efi/mm: Fix possible NULL pointer dereference
|
||
|
|
|
||
|
|
The model of grub_efi_get_memory_map() is that if memory_map is NULL,
|
||
|
|
then the purpose is to discover how much memory should be allocated to
|
||
|
|
it for the subsequent call.
|
||
|
|
|
||
|
|
The problem here is that with grub_efi_is_finished set to 1, there is no
|
||
|
|
check at all that the function is being called with a non-NULL memory_map.
|
||
|
|
|
||
|
|
While this MAY be true, we shouldn't assume it.
|
||
|
|
|
||
|
|
The solution to this is to behave as expected, and if memory_map is NULL,
|
||
|
|
then don't try to use it and allow memory_map_size to be filled in, and
|
||
|
|
return 0 as is done later in the code if the buffer is too small (or NULL).
|
||
|
|
|
||
|
|
Additionally, drop unneeded ret = 1.
|
||
|
|
|
||
|
|
Fixes: CID 96632
|
||
|
|
|
||
|
|
Signed-off-by: Darren Kenny <darren.kenny@oracle.com>
|
||
|
|
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
|
||
|
|
---
|
||
|
|
grub-core/kern/efi/mm.c | 23 ++++++++++++++++-------
|
||
|
|
1 file changed, 16 insertions(+), 7 deletions(-)
|
||
|
|
|
||
|
|
diff --git a/grub-core/kern/efi/mm.c b/grub-core/kern/efi/mm.c
|
||
|
|
index 306924f73..2d9c9032b 100644
|
||
|
|
--- a/grub-core/kern/efi/mm.c
|
||
|
|
+++ b/grub-core/kern/efi/mm.c
|
||
|
|
@@ -372,16 +372,25 @@ grub_efi_get_memory_map (grub_efi_uintn_t *memory_map_size,
|
||
|
|
if (grub_efi_is_finished)
|
||
|
|
{
|
||
|
|
int ret = 1;
|
||
|
|
- if (*memory_map_size < finish_mmap_size)
|
||
|
|
+
|
||
|
|
+ if (memory_map != NULL)
|
||
|
|
{
|
||
|
|
- grub_memcpy (memory_map, finish_mmap_buf, *memory_map_size);
|
||
|
|
+ if (*memory_map_size < finish_mmap_size)
|
||
|
|
+ {
|
||
|
|
+ grub_memcpy (memory_map, finish_mmap_buf, *memory_map_size);
|
||
|
|
+ ret = 0;
|
||
|
|
+ }
|
||
|
|
+ else
|
||
|
|
+ grub_memcpy (memory_map, finish_mmap_buf, finish_mmap_size);
|
||
|
|
+ }
|
||
|
|
+ else
|
||
|
|
+ {
|
||
|
|
+ /*
|
||
|
|
+ * Incomplete, no buffer to copy into, same as
|
||
|
|
+ * GRUB_EFI_BUFFER_TOO_SMALL below.
|
||
|
|
+ */
|
||
|
|
ret = 0;
|
||
|
|
}
|
||
|
|
- else
|
||
|
|
- {
|
||
|
|
- grub_memcpy (memory_map, finish_mmap_buf, finish_mmap_size);
|
||
|
|
- ret = 1;
|
||
|
|
- }
|
||
|
|
*memory_map_size = finish_mmap_size;
|
||
|
|
if (map_key)
|
||
|
|
*map_key = finish_key;
|