From 84d5140022d7531449720990ea6f36e8315c3504 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 27 Feb 2018 10:04:55 +0000 Subject: [PATCH] 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 Signed-off-by: David Howells Reviewed-by: Ard Biesheuvel cc: linux-efi@vger.kernel.org [Rebased for context; efi_is_table_address was moved to arch/x86] Signed-off-by: Jeremy Cline --- arch/x86/kernel/setup.c | 14 +----------- drivers/firmware/efi/Makefile | 1 + drivers/firmware/efi/secureboot.c | 38 +++++++++++++++++++++++++++++++ include/linux/efi.h | 18 ++++++++++----- 4 files changed, 52 insertions(+), 19 deletions(-) create mode 100644 drivers/firmware/efi/secureboot.c diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index e39ec0f88d28..08e9f5fc26a8 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -1250,19 +1250,7 @@ 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(); diff --git a/drivers/firmware/efi/Makefile b/drivers/firmware/efi/Makefile index 7a216984552b..f0ef02d733af 100644 --- a/drivers/firmware/efi/Makefile +++ b/drivers/firmware/efi/Makefile @@ -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 diff --git a/drivers/firmware/efi/secureboot.c b/drivers/firmware/efi/secureboot.c new file mode 100644 index 000000000000..de0a3714a5d4 --- /dev/null +++ b/drivers/firmware/efi/secureboot.c @@ -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 +#include +#include + +/* + * 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; + } + } +} diff --git a/include/linux/efi.h b/include/linux/efi.h index fa8e23680314..a9a9e7e976e7 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -778,6 +778,14 @@ 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 /* @@ -789,6 +797,8 @@ 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) @@ -815,6 +825,8 @@ 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 -- 2.26.0