[PATCH 1/1] efi: avoid NULL dereference if FilePath is NULL

[PATCH 1/1] efi: avoid NULL dereference if FilePath is NULL

[Heinrich Schuchardt]

The UEFI specification allows LoadImage() to be called with a memory
location only and without a device path. In this case FilePath will not be
set in the EFI_LOADED_IMAGE_PROTOCOL.

So in function grub_efi_get_filename() the device path argument may be
NULL. As we cannot determine the device path in this case just return NULL
from the function.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
---
Resend
Cc: grub-devel@gnu.org
---
 grub-core/kern/efi/efi.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/grub-core/kern/efi/efi.c b/grub-core/kern/efi/efi.c
index 708581fcb..84e68cf31 100644
--- a/grub-core/kern/efi/efi.c
+++ b/grub-core/kern/efi/efi.c
@@ -327,6 +327,9 @@ grub_efi_get_filename (grub_efi_device_path_t *dp0)
   grub_size_t filesize = 0;
   grub_efi_device_path_t *dp;

+  if (!dp0)
+    return NULL;
+
   dp = dp0;

   while (1)
--
2.20.1

Re: [PATCH 1/1] efi: avoid NULL dereference if FilePath is NULL

[Daniel Kiper]

On Wed, Apr 17, 2019 at 07:12:56AM +0200, Heinrich Schuchardt wrote:
> The UEFI specification allows LoadImage() to be called with a memory
> location only and without a device path. In this case FilePath will not be
> set in the EFI_LOADED_IMAGE_PROTOCOL.
>
> So in function grub_efi_get_filename() the device path argument may be
> NULL. As we cannot determine the device path in this case just return NULL
> from the function.
>
> Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
> Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>

Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

Daniel