2024-03-23 06:33:53

by Oleksandr Tymoshenko

Subject: [PATCH v2] efi: fix panic in kdump kernel

Check if get_next_variable() is actually valid pointer before
calling it. In kdump kernel this method is set to NULL that causes
panic during the kexec-ed kernel boot.

Tested with QEMU and OVMF firmware.

Fixes: bad267f9e18f ("efi: verify that variable services are supported")
Cc: [email protected]
Signed-off-by: Oleksandr Tymoshenko <[email protected]>
---
Changes in v2:
- Style fix
- Added Cc: stable
- Added Fixes: trailer
---
drivers/firmware/efi/efi.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 8859fb0b006d..fdf07dd6f459 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -203,6 +203,8 @@ static bool generic_ops_supported(void)

name_size = sizeof(name);

+ if (!efi.get_next_variable)
+ return false;
status = efi.get_next_variable(&name_size, &name, &guid);
if (status == EFI_UNSUPPORTED)
return false;
--
2.44.0.396.g6e790dbe36-goog

2024-03-23 12:16:16

by Ard Biesheuvel

Subject: Re: [PATCH v2] efi: fix panic in kdump kernel

On Sat, 23 Mar 2024 at 08:33, Oleksandr Tymoshenko <[email protected]> wrote:
>
> Check if get_next_variable() is actually valid pointer before
> calling it. In kdump kernel this method is set to NULL that causes
> panic during the kexec-ed kernel boot.
>
> Tested with QEMU and OVMF firmware.
>
> Fixes: bad267f9e18f ("efi: verify that variable services are supported")
> Cc: [email protected]
> Signed-off-by: Oleksandr Tymoshenko <[email protected]>

Thanks. Queued as a fix.

> ---
> Changes in v2:
> - Style fix
> - Added Cc: stable
> - Added Fixes: trailer
> ---
> drivers/firmware/efi/efi.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> index 8859fb0b006d..fdf07dd6f459 100644
> --- a/drivers/firmware/efi/efi.c
> +++ b/drivers/firmware/efi/efi.c
> @@ -203,6 +203,8 @@ static bool generic_ops_supported(void)
>
> name_size = sizeof(name);
>
> + if (!efi.get_next_variable)
> + return false;
> status = efi.get_next_variable(&name_size, &name, &guid);
> if (status == EFI_UNSUPPORTED)
> return false;
> --
> 2.44.0.396.g6e790dbe36-goog
>