1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Copyright (C) 2005,2006,2007,2008 IBM Corporation |
4 | * |
5 | * Authors: |
6 | * Reiner Sailer <sailer@watson.ibm.com> |
7 | * Leendert van Doorn <leendert@watson.ibm.com> |
8 | * Mimi Zohar <zohar@us.ibm.com> |
9 | * |
10 | * File: ima_init.c |
11 | * initialization and cleanup functions |
12 | */ |
13 | |
14 | #include <linux/init.h> |
15 | #include <linux/scatterlist.h> |
16 | #include <linux/slab.h> |
17 | #include <linux/err.h> |
18 | #include <linux/ima.h> |
19 | #include <generated/utsrelease.h> |
20 | |
21 | #include "ima.h" |
22 | |
23 | /* name for boot aggregate entry */ |
24 | const char boot_aggregate_name[] = "boot_aggregate" ; |
25 | struct tpm_chip *ima_tpm_chip; |
26 | |
27 | /* Add the boot aggregate to the IMA measurement list and extend |
28 | * the PCR register. |
29 | * |
30 | * Calculate the boot aggregate, a hash over tpm registers 0-7, |
31 | * assuming a TPM chip exists, and zeroes if the TPM chip does not |
32 | * exist. Add the boot aggregate measurement to the measurement |
33 | * list and extend the PCR register. |
34 | * |
35 | * If a tpm chip does not exist, indicate the core root of trust is |
36 | * not hardware based by invalidating the aggregate PCR value. |
37 | * (The aggregate PCR value is invalidated by adding one value to |
38 | * the measurement list and extending the aggregate PCR value with |
39 | * a different value.) Violations add a zero entry to the measurement |
40 | * list and extend the aggregate PCR value with ff...ff's. |
41 | */ |
42 | static int __init ima_add_boot_aggregate(void) |
43 | { |
44 | static const char op[] = "add_boot_aggregate" ; |
45 | const char *audit_cause = "ENOMEM" ; |
46 | struct ima_template_entry *entry; |
47 | struct ima_iint_cache tmp_iint, *iint = &tmp_iint; |
48 | struct ima_event_data event_data = { .iint = iint, |
49 | .filename = boot_aggregate_name }; |
50 | struct ima_max_digest_data hash; |
51 | int result = -ENOMEM; |
52 | int violation = 0; |
53 | |
54 | memset(iint, 0, sizeof(*iint)); |
55 | memset(&hash, 0, sizeof(hash)); |
56 | iint->ima_hash = &hash.hdr; |
57 | iint->ima_hash->algo = ima_hash_algo; |
58 | iint->ima_hash->length = hash_digest_size[ima_hash_algo]; |
59 | |
60 | /* |
61 | * With TPM 2.0 hash agility, TPM chips could support multiple TPM |
62 | * PCR banks, allowing firmware to configure and enable different |
63 | * banks. The SHA1 bank is not necessarily enabled. |
64 | * |
65 | * Use the same hash algorithm for reading the TPM PCRs as for |
66 | * calculating the boot aggregate digest. Preference is given to |
67 | * the configured IMA default hash algorithm. Otherwise, use the |
68 | * TCG required banks - SHA256 for TPM 2.0, SHA1 for TPM 1.2. |
69 | * Ultimately select SHA1 also for TPM 2.0 if the SHA256 PCR bank |
70 | * is not found. |
71 | */ |
72 | if (ima_tpm_chip) { |
73 | result = ima_calc_boot_aggregate(hash: &hash.hdr); |
74 | if (result < 0) { |
75 | audit_cause = "hashing_error" ; |
76 | goto err_out; |
77 | } |
78 | } |
79 | |
80 | result = ima_alloc_init_template(event_data: &event_data, entry: &entry, NULL); |
81 | if (result < 0) { |
82 | audit_cause = "alloc_entry" ; |
83 | goto err_out; |
84 | } |
85 | |
86 | result = ima_store_template(entry, violation, NULL, |
87 | filename: boot_aggregate_name, |
88 | CONFIG_IMA_MEASURE_PCR_IDX); |
89 | if (result < 0) { |
90 | ima_free_template_entry(entry); |
91 | audit_cause = "store_entry" ; |
92 | goto err_out; |
93 | } |
94 | return 0; |
95 | err_out: |
96 | integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, fname: boot_aggregate_name, op, |
97 | cause: audit_cause, result, info: 0); |
98 | return result; |
99 | } |
100 | |
101 | #ifdef CONFIG_IMA_LOAD_X509 |
102 | void __init ima_load_x509(void) |
103 | { |
104 | int unset_flags = ima_policy_flag & IMA_APPRAISE; |
105 | |
106 | ima_policy_flag &= ~unset_flags; |
107 | integrity_load_x509(INTEGRITY_KEYRING_IMA, CONFIG_IMA_X509_PATH); |
108 | |
109 | /* load also EVM key to avoid appraisal */ |
110 | evm_load_x509(); |
111 | |
112 | ima_policy_flag |= unset_flags; |
113 | } |
114 | #endif |
115 | |
116 | int __init ima_init(void) |
117 | { |
118 | int rc; |
119 | |
120 | ima_tpm_chip = tpm_default_chip(); |
121 | if (!ima_tpm_chip) |
122 | pr_info("No TPM chip found, activating TPM-bypass!\n" ); |
123 | |
124 | rc = integrity_init_keyring(INTEGRITY_KEYRING_IMA); |
125 | if (rc) |
126 | return rc; |
127 | |
128 | rc = ima_init_crypto(); |
129 | if (rc) |
130 | return rc; |
131 | rc = ima_init_template(); |
132 | if (rc != 0) |
133 | return rc; |
134 | |
135 | /* It can be called before ima_init_digests(), it does not use TPM. */ |
136 | ima_load_kexec_buffer(); |
137 | |
138 | rc = ima_init_digests(); |
139 | if (rc != 0) |
140 | return rc; |
141 | rc = ima_add_boot_aggregate(); /* boot aggregate must be first entry */ |
142 | if (rc != 0) |
143 | return rc; |
144 | |
145 | ima_init_policy(); |
146 | |
147 | rc = ima_fs_init(); |
148 | if (rc != 0) |
149 | return rc; |
150 | |
151 | ima_init_key_queue(); |
152 | |
153 | ima_measure_critical_data(event_label: "kernel_info" , event_name: "kernel_version" , |
154 | UTS_RELEASE, strlen(UTS_RELEASE), hash: false, |
155 | NULL, digest_len: 0); |
156 | |
157 | return rc; |
158 | } |
159 | |