forked from Minki/linux
558b523d46
Checking efi_enabled(EFI_BOOT) is not sufficient to ensure that
EFI runtime services are available, e.g. if efi=noruntime is used.
Without this, I get an oops on a PREEMPT_RT kernel where efi=noruntime is
the default.
Fixes: 399574c64e ("x86/ima: retry detecting secure boot mode")
Cc: stable@vger.kernel.org (linux-5.0)
Signed-off-by: Scott Wood <swood@redhat.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
89 lines
2.1 KiB
C
89 lines
2.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0+ */
|
|
/*
|
|
* Copyright (C) 2018 IBM Corporation
|
|
*/
|
|
#include <linux/efi.h>
|
|
#include <linux/module.h>
|
|
#include <linux/ima.h>
|
|
|
|
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);
|
|
|
|
if (!efi_enabled(EFI_RUNTIME_SERVICES)) {
|
|
pr_info("ima: secureboot mode unknown, no efi\n");
|
|
return efi_secureboot_mode_unknown;
|
|
}
|
|
|
|
/* 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)
|
|
{
|
|
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;
|
|
}
|
|
|
|
/* secureboot arch rules */
|
|
static const char * const sb_arch_rules[] = {
|
|
#if !IS_ENABLED(CONFIG_KEXEC_VERIFY_SIG)
|
|
"appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig",
|
|
#endif /* CONFIG_KEXEC_VERIFY_SIG */
|
|
"measure func=KEXEC_KERNEL_CHECK",
|
|
#if !IS_ENABLED(CONFIG_MODULE_SIG)
|
|
"appraise func=MODULE_CHECK appraise_type=imasig",
|
|
#endif
|
|
"measure func=MODULE_CHECK",
|
|
NULL
|
|
};
|
|
|
|
const char * const *arch_get_ima_policy(void)
|
|
{
|
|
if (IS_ENABLED(CONFIG_IMA_ARCH_POLICY) && arch_ima_get_secureboot()) {
|
|
if (IS_ENABLED(CONFIG_MODULE_SIG))
|
|
set_module_sig_enforced();
|
|
return sb_arch_rules;
|
|
}
|
|
return NULL;
|
|
}
|