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