On Tue, Nov 22, 2016 at 12:32:08AM +0000, David Howells wrote:
> From: Josh Boyer <jwboyer@xxxxxxxxxxxxxxxxx>
>
> A user can manually tell the shim boot loader to disable validation of
> images it loads. When a user does this, it creates a UEFI variable called
> MokSBState that does not have the runtime attribute set. Given that the
> user explicitly disabled validation, we can honor that and not enable
> secure boot mode if that variable is set.
>
> Signed-off-by: Josh Boyer <jwboyer@xxxxxxxxxxxxxxxxx>
> Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
> ---
>
> drivers/firmware/efi/libstub/secureboot.c | 22 +++++++++++++++++++++-
> 1 file changed, 21 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/firmware/efi/libstub/secureboot.c b/drivers/firmware/efi/libstub/secureboot.c
> index e44d8c9ee150..d928398a3a52 100644
> --- a/drivers/firmware/efi/libstub/secureboot.c
> +++ b/drivers/firmware/efi/libstub/secureboot.c
> @@ -23,10 +23,14 @@ int efi_get_secureboot(void)
> 'S', 'e', 'c', 'u', 'r', 'e', 'B', 'o', 'o', 't', 0 };
> static const efi_char16_t const sm_var_name[] = {
> 'S', 'e', 't', 'u', 'p', 'M', 'o', 'd', 'e', 0 };
> + static efi_char16_t const MokSBState_var_name[] = {
> + 'M', 'o', 'k', 'S', 'B', 'S', 't', 'a', 't', 'e', 0 };
>
> static const efi_guid_t var_guid = EFI_GLOBAL_VARIABLE_GUID;
> + static const efi_guid_t shim_guid = EFI_SHIM_LOCK_GUID;
>
> - u8 val;
> + u32 attr;
> + u8 val, moksbstate;
> unsigned long size = sizeof(val);
> efi_status_t status;
>
> @@ -50,6 +54,22 @@ int efi_get_secureboot(void)
> if (val == 1)
> return 0;
>
> + /* See if a user has put shim into insecure mode. If so, and if the
> + * variable doesn't have the runtime attribute set, we might as well
> + * honor that.
> + */
> + size = sizeof(moksbstate);
> + status = f_getvar((efi_char16_t *)MokSBState_var_name, &shim_guid,
> + &attr, &size, &moksbstate);
Please use efi_call_runtime() instead of f_getvar().
> +
> + /* If it fails, we don't care why. Default to secure */
> + if (status != EFI_SUCCESS)
> + return 1;
> +
> + if (!(attr & EFI_VARIABLE_RUNTIME_ACCESS) &&
> + moksbstate == 1)
This would fit on a single line.
Thanks,
Lukas
> + return 0;
> +
> return 1;
>
> out_efi_err:
>
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