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x86/ima: retry detecting secure boot mode 

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@linux.ibm.com>
hifive-unleashed-5.1
Mimi Zohar 2018-11-18 04:08:12 -05:00
parent 4264f27a08
commit 399574c64e
3 changed files with 47 additions and 3 deletions
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2
arch/x86/kernel/Makefile
View File

@ -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

46
arch/x86/kernel/ima_arch.c
View File

@ -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;

2
include/linux/ima.h
View File

@ -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