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// SPDX-License-Identifier: GPL-2.0
/*
* Secure boot handling.
*
* Copyright (C) 2013,2014 Linaro Limited
* Roy Franz <roy.franz@linaro.org
* Copyright (C) 2013 Red Hat, Inc.
* Mark Salter <msalter@redhat.com>
*/
#include <linux/efi.h>
#include <asm/efi.h>
#include "efistub.h"
/* SHIM variables */
static const efi_guid_t shim_guid = EFI_SHIM_LOCK_GUID;
static const efi_char16_t shim_MokSBState_name[] = L"MokSBState";
static efi_status_t get_var(efi_char16_t *name, efi_guid_t *vendor, u32 *attr,
unsigned long *data_size, void *data)
{
return get_efi_var(name, vendor, attr, data_size, data);
}
/*
* Determine whether we're in secure boot mode.
*/
enum efi_secureboot_mode efi_get_secureboot(void)
{
u32 attr;
unsigned long size;
enum efi_secureboot_mode mode;
efi_status_t status;
u8 moksbstate;
mode = efi_get_secureboot_mode(get_var);
if (mode == efi_secureboot_mode_unknown) {
efi_err("Could not determine UEFI Secure Boot status.\n");
return efi_secureboot_mode_unknown;
}
if (mode != efi_secureboot_mode_enabled)
return mode;
/*
* See if a user has put the 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 = get_efi_var(shim_MokSBState_name, &shim_guid,
&attr, &size, &moksbstate);
/* If it fails, we don't care why. Default to secure */
if (status != EFI_SUCCESS)
goto secure_boot_enabled;
if (!(attr & EFI_VARIABLE_RUNTIME_ACCESS) && moksbstate == 1)
return efi_secureboot_mode_disabled;
secure_boot_enabled:
efi_info("UEFI Secure Boot is enabled.\n");
return efi_secureboot_mode_enabled;
}
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