1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * Copyright (C) 2019 IBM Corporation
 4 * Author: Nayna Jain
 5 */
 6
 7#include <linux/ima.h>
 8#include <asm/secure_boot.h>
 9
10bool arch_ima_get_secureboot(void)
11{
12	return is_ppc_secureboot_enabled();
13}
14
15/*
16 * The "secure_rules" are enabled only on "secureboot" enabled systems.
17 * These rules verify the file signatures against known good values.
18 * The "appraise_type=imasig|modsig" option allows the known good signature
19 * to be stored as an xattr or as an appended signature.
20 *
21 * To avoid duplicate signature verification as much as possible, the IMA
22 * policy rule for module appraisal is added only if CONFIG_MODULE_SIG
23 * is not enabled.
24 */
25static const char *const secure_rules[] = {
26	"appraise func=KEXEC_KERNEL_CHECK appraise_flag=check_blacklist appraise_type=imasig|modsig",
27#ifndef CONFIG_MODULE_SIG
28	"appraise func=MODULE_CHECK appraise_flag=check_blacklist appraise_type=imasig|modsig",
29#endif
30	NULL
31};
32
33/*
34 * The "trusted_rules" are enabled only on "trustedboot" enabled systems.
35 * These rules add the kexec kernel image and kernel modules file hashes to
36 * the IMA measurement list.
37 */
38static const char *const trusted_rules[] = {
39	"measure func=KEXEC_KERNEL_CHECK",
40	"measure func=MODULE_CHECK",
41	NULL
42};
43
44/*
45 * The "secure_and_trusted_rules" contains rules for both the secure boot and
46 * trusted boot. The "template=ima-modsig" option includes the appended
47 * signature, when available, in the IMA measurement list.
48 */
49static const char *const secure_and_trusted_rules[] = {
50	"measure func=KEXEC_KERNEL_CHECK template=ima-modsig",
51	"measure func=MODULE_CHECK template=ima-modsig",
52	"appraise func=KEXEC_KERNEL_CHECK appraise_flag=check_blacklist appraise_type=imasig|modsig",
53#ifndef CONFIG_MODULE_SIG
54	"appraise func=MODULE_CHECK appraise_flag=check_blacklist appraise_type=imasig|modsig",
55#endif
56	NULL
57};
58
59/*
60 * Returns the relevant IMA arch-specific policies based on the system secure
61 * boot state.
62 */
63const char *const *arch_get_ima_policy(void)
64{
65	if (is_ppc_secureboot_enabled()) {
66		if (IS_ENABLED(CONFIG_MODULE_SIG))
67			set_module_sig_enforced();
68
69		if (is_ppc_trustedboot_enabled())
70			return secure_and_trusted_rules;
71		else
72			return secure_rules;
73	} else if (is_ppc_trustedboot_enabled()) {
74		return trusted_rules;
75	}
76
77	return NULL;
78}