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 */
22const char boot_aggregate_name[] = "boot_aggregate";
23struct 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 */
40static 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;
96err_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
103void __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
113int __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