efi: Add an EFI_SECURE_BOOT flag to indicate secure boot mode

UEFI machines can be booted in Secure Boot mode.  Add an EFI_SECURE_BOOT
flag that can be passed to efi_enabled() to find out whether secure boot is
enabled.

Move the switch-statement in x86's setup_arch() that inteprets the
secure_boot boot parameter to generic code and set the bit there.

Upstream Status: RHEL only
Suggested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
cc: linux-efi@vger.kernel.org
[Rebased for context; efi_is_table_address was moved to arch/x86]
Signed-off-by: Jeremy Cline <jcline@redhat.com>
This commit is contained in:
David Howells 2018-02-27 10:04:55 +00:00 committed by Liu Yang
parent cd7c2d9a7d
commit 02805b583f
4 changed files with 52 additions and 19 deletions

View file

@ -1112,19 +1112,7 @@ void __init setup_arch(char **cmdline_p)
/* Allocate bigger log buffer */
setup_log_buf(1);
if (efi_enabled(EFI_BOOT)) {
switch (boot_params.secure_boot) {
case efi_secureboot_mode_disabled:
pr_info("Secure boot disabled\n");
break;
case efi_secureboot_mode_enabled:
pr_info("Secure boot enabled\n");
break;
default:
pr_info("Secure boot could not be determined\n");
break;
}
}
efi_set_secure_boot(boot_params.secure_boot);
reserve_initrd();

View file

@ -25,6 +25,7 @@ obj-$(CONFIG_EFI_FAKE_MEMMAP) += fake_map.o
obj-$(CONFIG_EFI_BOOTLOADER_CONTROL) += efibc.o
obj-$(CONFIG_EFI_TEST) += test/
obj-$(CONFIG_EFI_DEV_PATH_PARSER) += dev-path-parser.o
obj-$(CONFIG_EFI) += secureboot.o
obj-$(CONFIG_APPLE_PROPERTIES) += apple-properties.o
obj-$(CONFIG_EFI_RCI2_TABLE) += rci2-table.o
obj-$(CONFIG_EFI_EMBEDDED_FIRMWARE) += embedded-firmware.o

View file

@ -0,0 +1,38 @@
/* Core kernel secure boot support.
*
* Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/efi.h>
#include <linux/kernel.h>
#include <linux/printk.h>
/*
* Decide what to do when UEFI secure boot mode is enabled.
*/
void __init efi_set_secure_boot(enum efi_secureboot_mode mode)
{
if (efi_enabled(EFI_BOOT)) {
switch (mode) {
case efi_secureboot_mode_disabled:
pr_info("Secure boot disabled\n");
break;
case efi_secureboot_mode_enabled:
set_bit(EFI_SECURE_BOOT, &efi.flags);
pr_info("Secure boot enabled\n");
break;
default:
pr_warn("Secure boot could not be determined (mode %u)\n",
mode);
break;
}
}
}

View file

@ -788,6 +788,14 @@ extern int __init efi_setup_pcdp_console(char *);
#define EFI_MEM_ATTR 10 /* Did firmware publish an EFI_MEMORY_ATTRIBUTES table? */
#define EFI_MEM_NO_SOFT_RESERVE 11 /* Is the kernel configured to ignore soft reservations? */
#define EFI_PRESERVE_BS_REGIONS 12 /* Are EFI boot-services memory segments available? */
#define EFI_SECURE_BOOT 13 /* Are we in Secure Boot mode? */
enum efi_secureboot_mode {
efi_secureboot_mode_unset,
efi_secureboot_mode_unknown,
efi_secureboot_mode_disabled,
efi_secureboot_mode_enabled,
};
#ifdef CONFIG_EFI
/*
@ -799,6 +807,8 @@ static inline bool efi_enabled(int feature)
}
extern void efi_reboot(enum reboot_mode reboot_mode, const char *__unused);
extern void __init efi_set_secure_boot(enum efi_secureboot_mode mode);
bool __pure __efi_soft_reserve_enabled(void);
static inline bool __pure efi_soft_reserve_enabled(void)
@ -825,6 +835,8 @@ efi_capsule_pending(int *reset_type)
return false;
}
static inline void efi_set_secure_boot(enum efi_secureboot_mode mode) {}
static inline bool efi_soft_reserve_enabled(void)
{
return false;
@ -1086,12 +1098,6 @@ static inline bool efi_runtime_disabled(void) { return true; }
extern void efi_call_virt_check_flags(unsigned long flags, const char *call);
extern unsigned long efi_call_virt_save_flags(void);
enum efi_secureboot_mode {
efi_secureboot_mode_unset,
efi_secureboot_mode_unknown,
efi_secureboot_mode_disabled,
efi_secureboot_mode_enabled,
};
enum efi_secureboot_mode efi_get_secureboot(void);
#ifdef CONFIG_RESET_ATTACK_MITIGATION