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/* 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_guid_t efi_variable_guid = EFI_GLOBAL_VARIABLE_GUID;
efi_status_t status;
unsigned long size;
u8 secboot, setupmode;
size = sizeof(secboot);
if (!efi_rt_services_supported(EFI_RT_SUPPORTED_GET_VARIABLE)) {
pr_info("ima: secureboot mode unknown, no efi\n");
return efi_secureboot_mode_unknown;
}
/* Get variable contents into buffer */
status = efi.get_variable(L"SecureBoot", &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;
}
size = sizeof(setupmode);
status = efi.get_variable(L"SetupMode", &efi_variable_guid,
NULL, &size, &setupmode);
if (status != EFI_SUCCESS) /* ignore unknown SetupMode */
setupmode = 0;
if (secboot == 0 || setupmode == 1) {
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_SIG)
"appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig",
#endif /* CONFIG_KEXEC_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;
}
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