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
10 bool 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 */
25 static const char *const secure_rules[] = {
26 "appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig|modsig",
27 #ifndef CONFIG_MODULE_SIG
28 "appraise func=MODULE_CHECK 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 */
38 static 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 */
49 static 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_type=imasig|modsig",
53 #ifndef CONFIG_MODULE_SIG
54 "appraise func=MODULE_CHECK 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 */
63 const 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 }
79
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