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 */
ima_add_boot_aggregate(void)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 integrity_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.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, &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 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, boot_aggregate_name, op,
97 audit_cause, result, 0);
98 return result;
99 }
100
101 #ifdef CONFIG_IMA_LOAD_X509
ima_load_x509(void)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
ima_init(void)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("kernel_info", "kernel_version",
154 UTS_RELEASE, strlen(UTS_RELEASE), false,
155 NULL, 0);
156
157 return rc;
158 }
159