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 */
24const char boot_aggregate_name[] = "boot_aggregate";
25struct 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 */
42static 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.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;
95err_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
102void __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
116int __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