The secure boot mode may not be detected on boot for some reason (eg. buggy firmware). This patch attempts one more time to detect the secure boot mode. Signed-off-by: Mimi Zohar <zohar@xxxxxxxxxxxxx> --- arch/x86/kernel/Makefile | 2 ++ arch/x86/kernel/ima_arch.c | 46 ++++++++++++++++++++++++++++++++++++++++++++-- include/linux/ima.h | 2 +- 3 files changed, 47 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index f0910a1e1db7..eb51b0e1189c 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -151,4 +151,6 @@ ifeq ($(CONFIG_X86_64),y) obj-y += vsmp_64.o endif +ifdef CONFIG_EFI obj-$(CONFIG_IMA) += ima_arch.o +endif diff --git a/arch/x86/kernel/ima_arch.c b/arch/x86/kernel/ima_arch.c index 6c248616ee57..e47cd9390ab4 100644 --- a/arch/x86/kernel/ima_arch.c +++ b/arch/x86/kernel/ima_arch.c @@ -7,10 +7,52 @@ extern struct boot_params boot_params; +static enum efi_secureboot_mode get_sb_mode(void) +{ + efi_char16_t efi_SecureBoot_name[] = L"SecureBoot"; + efi_guid_t efi_variable_guid = EFI_GLOBAL_VARIABLE_GUID; + efi_status_t status; + unsigned long size; + u8 secboot; + + size = sizeof(secboot); + + /* Get variable contents into buffer */ + status = efi.get_variable(efi_SecureBoot_name, &efi_variable_guid, + NULL, &size, &secboot); + if (status == EFI_NOT_FOUND) { + pr_info("ima: secureboot mode disabled\n"); + return efi_secureboot_mode_disabled; + } + + if (status != EFI_SUCCESS) { + pr_info("ima: secureboot mode unknown\n"); + return efi_secureboot_mode_unknown; + } + + if (secboot == 0) { + pr_info("ima: secureboot mode disabled\n"); + return efi_secureboot_mode_disabled; + } + + pr_info("ima: secureboot mode enabled\n"); + return efi_secureboot_mode_enabled; +} + bool arch_ima_get_secureboot(void) { - if (efi_enabled(EFI_BOOT) && - (boot_params.secure_boot == efi_secureboot_mode_enabled)) + static enum efi_secureboot_mode sb_mode; + static bool initialized; + + if (!initialized && efi_enabled(EFI_BOOT)) { + sb_mode = boot_params.secure_boot; + + if (sb_mode == efi_secureboot_mode_unset) + sb_mode = get_sb_mode(); + initialized = true; + } + + if (sb_mode == efi_secureboot_mode_enabled) return true; else return false; diff --git a/include/linux/ima.h b/include/linux/ima.h index 5ab9134d4fd7..b5e16b8c50b7 100644 --- a/include/linux/ima.h +++ b/include/linux/ima.h @@ -30,7 +30,7 @@ extern void ima_post_path_mknod(struct dentry *dentry); extern void ima_add_kexec_buffer(struct kimage *image); #endif -#ifdef CONFIG_X86 +#if defined(CONFIG_X86) && defined(CONFIG_EFI) extern bool arch_ima_get_secureboot(void); extern const char * const *arch_get_ima_policy(void); #else -- 2.7.5