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
19 #include "ima.h"
20
21 /* name for boot aggregate entry */
22 const char boot_aggregate_name[] = "boot_aggregate";
23 struct tpm_chip *ima_tpm_chip;
24
25 /* Add the boot aggregate to the IMA measurement list and extend
26 * the PCR register.
27 *
28 * Calculate the boot aggregate, a hash over tpm registers 0-7,
29 * assuming a TPM chip exists, and zeroes if the TPM chip does not
30 * exist. Add the boot aggregate measurement to the measurement
31 * list and extend the PCR register.
32 *
33 * If a tpm chip does not exist, indicate the core root of trust is
34 * not hardware based by invalidating the aggregate PCR value.
35 * (The aggregate PCR value is invalidated by adding one value to
36 * the measurement list and extending the aggregate PCR value with
37 * a different value.) Violations add a zero entry to the measurement
38 * list and extend the aggregate PCR value with ff...ff's.
39 */
ima_add_boot_aggregate(void)40 static int __init ima_add_boot_aggregate(void)
41 {
42 static const char op[] = "add_boot_aggregate";
43 const char *audit_cause = "ENOMEM";
44 struct ima_template_entry *entry;
45 struct integrity_iint_cache tmp_iint, *iint = &tmp_iint;
46 struct ima_event_data event_data = { .iint = iint,
47 .filename = boot_aggregate_name };
48 int result = -ENOMEM;
49 int violation = 0;
50 struct {
51 struct ima_digest_data hdr;
52 char digest[TPM_MAX_DIGEST_SIZE];
53 } hash;
54
55 memset(iint, 0, sizeof(*iint));
56 memset(&hash, 0, sizeof(hash));
57 iint->ima_hash = &hash.hdr;
58 iint->ima_hash->algo = ima_hash_algo;
59 iint->ima_hash->length = hash_digest_size[ima_hash_algo];
60
61 /*
62 * With TPM 2.0 hash agility, TPM chips could support multiple TPM
63 * PCR banks, allowing firmware to configure and enable different
64 * banks. The SHA1 bank is not necessarily enabled.
65 *
66 * Use the same hash algorithm for reading the TPM PCRs as for
67 * calculating the boot aggregate digest. Preference is given to
68 * the configured IMA default hash algorithm. Otherwise, use the
69 * TCG required banks - SHA256 for TPM 2.0, SHA1 for TPM 1.2.
70 * Ultimately select SHA1 also for TPM 2.0 if the SHA256 PCR bank
71 * is not found.
72 */
73 if (ima_tpm_chip) {
74 result = ima_calc_boot_aggregate(&hash.hdr);
75 if (result < 0) {
76 audit_cause = "hashing_error";
77 goto err_out;
78 }
79 }
80
81 result = ima_alloc_init_template(&event_data, &entry, NULL);
82 if (result < 0) {
83 audit_cause = "alloc_entry";
84 goto err_out;
85 }
86
87 result = ima_store_template(entry, violation, NULL,
88 boot_aggregate_name,
89 CONFIG_IMA_MEASURE_PCR_IDX);
90 if (result < 0) {
91 ima_free_template_entry(entry);
92 audit_cause = "store_entry";
93 goto err_out;
94 }
95 return 0;
96 err_out:
97 integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, boot_aggregate_name, op,
98 audit_cause, result, 0);
99 return result;
100 }
101
102 #ifdef CONFIG_IMA_LOAD_X509
ima_load_x509(void)103 void __init ima_load_x509(void)
104 {
105 int unset_flags = ima_policy_flag & IMA_APPRAISE;
106
107 ima_policy_flag &= ~unset_flags;
108 integrity_load_x509(INTEGRITY_KEYRING_IMA, CONFIG_IMA_X509_PATH);
109 ima_policy_flag |= unset_flags;
110 }
111 #endif
112
ima_init(void)113 int __init ima_init(void)
114 {
115 int rc;
116
117 ima_tpm_chip = tpm_default_chip();
118 if (!ima_tpm_chip)
119 pr_info("No TPM chip found, activating TPM-bypass!\n");
120
121 rc = integrity_init_keyring(INTEGRITY_KEYRING_IMA);
122 if (rc)
123 return rc;
124
125 rc = ima_init_crypto();
126 if (rc)
127 return rc;
128 rc = ima_init_template();
129 if (rc != 0)
130 return rc;
131
132 /* It can be called before ima_init_digests(), it does not use TPM. */
133 ima_load_kexec_buffer();
134
135 rc = ima_init_digests();
136 if (rc != 0)
137 return rc;
138 rc = ima_add_boot_aggregate(); /* boot aggregate must be first entry */
139 if (rc != 0)
140 return rc;
141
142 ima_init_policy();
143
144 rc = ima_fs_init();
145 if (rc != 0)
146 return rc;
147
148 ima_init_key_queue();
149
150 return rc;
151 }
152