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 struct ima_digest_data *hash_hdr = container_of(&hash.hdr,
52 struct ima_digest_data, hdr);
53 int result = -ENOMEM;
54 int violation = 0;
55
56 memset(iint, 0, sizeof(*iint));
57 memset(&hash, 0, sizeof(hash));
58 iint->ima_hash = hash_hdr;
59 iint->ima_hash->algo = ima_hash_algo;
60 iint->ima_hash->length = hash_digest_size[ima_hash_algo];
61
62 /*
63 * With TPM 2.0 hash agility, TPM chips could support multiple TPM
64 * PCR banks, allowing firmware to configure and enable different
65 * banks. The SHA1 bank is not necessarily enabled.
66 *
67 * Use the same hash algorithm for reading the TPM PCRs as for
68 * calculating the boot aggregate digest. Preference is given to
69 * the configured IMA default hash algorithm. Otherwise, use the
70 * TCG required banks - SHA256 for TPM 2.0, SHA1 for TPM 1.2.
71 * Ultimately select SHA1 also for TPM 2.0 if the SHA256 PCR bank
72 * is not found.
73 */
74 if (ima_tpm_chip) {
75 result = ima_calc_boot_aggregate(hash_hdr);
76 if (result < 0) {
77 audit_cause = "hashing_error";
78 goto err_out;
79 }
80 }
81
82 result = ima_alloc_init_template(&event_data, &entry, NULL);
83 if (result < 0) {
84 audit_cause = "alloc_entry";
85 goto err_out;
86 }
87
88 result = ima_store_template(entry, violation, NULL,
89 boot_aggregate_name,
90 CONFIG_IMA_MEASURE_PCR_IDX);
91 if (result < 0) {
92 ima_free_template_entry(entry);
93 audit_cause = "store_entry";
94 goto err_out;
95 }
96 return 0;
97 err_out:
98 integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, boot_aggregate_name, op,
99 audit_cause, result, 0);
100 return result;
101 }
102
103 #ifdef CONFIG_IMA_LOAD_X509
104 void __init ima_load_x509(void)
105 {
106 int unset_flags = ima_policy_flag & IMA_APPRAISE;
107
108 ima_policy_flag &= ~unset_flags;
109 integrity_load_x509(INTEGRITY_KEYRING_IMA, CONFIG_IMA_X509_PATH);
110
111 /* load also EVM key to avoid appraisal */
112 evm_load_x509();
113
114 ima_policy_flag |= unset_flags;
115 }
116 #endif
117
118 int __init ima_init(void)
119 {
120 int rc;
121
122 ima_tpm_chip = tpm_default_chip();
123 if (!ima_tpm_chip)
124 pr_info("No TPM chip found, activating TPM-bypass!\n");
125
126 rc = integrity_init_keyring(INTEGRITY_KEYRING_IMA);
127 if (rc)
128 return rc;
129
130 rc = ima_init_crypto();
131 if (rc)
132 return rc;
133 rc = ima_init_template();
134 if (rc != 0)
135 return rc;
136
137 /* It can be called before ima_init_digests(), it does not use TPM. */
138 ima_load_kexec_buffer();
139
140 rc = ima_init_digests();
141 if (rc != 0)
142 return rc;
143 rc = ima_add_boot_aggregate(); /* boot aggregate must be first entry */
144 if (rc != 0)
145 return rc;
146
147 ima_init_policy();
148
149 rc = ima_fs_init();
150 if (rc != 0)
151 return rc;
152
153 ima_init_key_queue();
154
155 ima_measure_critical_data("kernel_info", "kernel_version",
156 UTS_RELEASE, strlen(UTS_RELEASE), false,
157 NULL, 0);
158
159 return rc;
160 }
161
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