summaryrefslogtreecommitdiffstats
path: root/security/integrity/ima/ima_init.c
blob: b26fa67476b411d35a576e9754a1f8d450e633b7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2005,2006,2007,2008 IBM Corporation
 *
 * Authors:
 * Reiner Sailer      <sailer@watson.ibm.com>
 * Leendert van Doorn <leendert@watson.ibm.com>
 * Mimi Zohar         <zohar@us.ibm.com>
 *
 * File: ima_init.c
 *             initialization and cleanup functions
 */

#include <linux/init.h>
#include <linux/scatterlist.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/ima.h>
#include <generated/utsrelease.h>

#include "ima.h"

/* name for boot aggregate entry */
const char boot_aggregate_name[] = "boot_aggregate";
struct tpm_chip *ima_tpm_chip;

/* Add the boot aggregate to the IMA measurement list and extend
 * the PCR register.
 *
 * Calculate the boot aggregate, a hash over tpm registers 0-7,
 * assuming a TPM chip exists, and zeroes if the TPM chip does not
 * exist.  Add the boot aggregate measurement to the measurement
 * list and extend the PCR register.
 *
 * If a tpm chip does not exist, indicate the core root of trust is
 * not hardware based by invalidating the aggregate PCR value.
 * (The aggregate PCR value is invalidated by adding one value to
 * the measurement list and extending the aggregate PCR value with
 * a different value.) Violations add a zero entry to the measurement
 * list and extend the aggregate PCR value with ff...ff's.
 */
static int __init ima_add_boot_aggregate(void)
{
	static const char op[] = "add_boot_aggregate";
	const char *audit_cause = "ENOMEM";
	struct ima_template_entry *entry;
	struct integrity_iint_cache tmp_iint, *iint = &tmp_iint;
	struct ima_event_data event_data = { .iint = iint,
					     .filename = boot_aggregate_name };
	int result = -ENOMEM;
	int violation = 0;
	struct {
		struct ima_digest_data hdr;
		char digest[TPM_MAX_DIGEST_SIZE];
	} hash;

	memset(iint, 0, sizeof(*iint));
	memset(&hash, 0, sizeof(hash));
	iint->ima_hash = &hash.hdr;
	iint->ima_hash->algo = ima_hash_algo;
	iint->ima_hash->length = hash_digest_size[ima_hash_algo];

	/*
	 * With TPM 2.0 hash agility, TPM chips could support multiple TPM
	 * PCR banks, allowing firmware to configure and enable different
	 * banks.  The SHA1 bank is not necessarily enabled.
	 *
	 * Use the same hash algorithm for reading the TPM PCRs as for
	 * calculating the boot aggregate digest.  Preference is given to
	 * the configured IMA default hash algorithm.  Otherwise, use the
	 * TCG required banks - SHA256 for TPM 2.0, SHA1 for TPM 1.2.
	 * Ultimately select SHA1 also for TPM 2.0 if the SHA256 PCR bank
	 * is not found.
	 */
	if (ima_tpm_chip) {
		result = ima_calc_boot_aggregate(&hash.hdr);
		if (result < 0) {
			audit_cause = "hashing_error";
			goto err_out;
		}
	}

	result = ima_alloc_init_template(&event_data, &entry, NULL);
	if (result < 0) {
		audit_cause = "alloc_entry";
		goto err_out;
	}

	result = ima_store_template(entry, violation, NULL,
				    boot_aggregate_name,
				    CONFIG_IMA_MEASURE_PCR_IDX);
	if (result < 0) {
		ima_free_template_entry(entry);
		audit_cause = "store_entry";
		goto err_out;
	}
	return 0;
err_out:
	integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, boot_aggregate_name, op,
			    audit_cause, result, 0);
	return result;
}

#ifdef CONFIG_IMA_LOAD_X509
void __init ima_load_x509(void)
{
	int unset_flags = ima_policy_flag & IMA_APPRAISE;

	ima_policy_flag &= ~unset_flags;
	integrity_load_x509(INTEGRITY_KEYRING_IMA, CONFIG_IMA_X509_PATH);

	/* load also EVM key to avoid appraisal */
	evm_load_x509();

	ima_policy_flag |= unset_flags;
}
#endif

int __init ima_init(void)
{
	int rc;

	ima_tpm_chip = tpm_default_chip();
	if (!ima_tpm_chip)
		pr_info("No TPM chip found, activating TPM-bypass!\n");

	rc = integrity_init_keyring(INTEGRITY_KEYRING_IMA);
	if (rc)
		return rc;

	rc = ima_init_crypto();
	if (rc)
		return rc;
	rc = ima_init_template();
	if (rc != 0)
		return rc;

	/* It can be called before ima_init_digests(), it does not use TPM. */
	ima_load_kexec_buffer();

	rc = ima_init_digests();
	if (rc != 0)
		return rc;
	rc = ima_add_boot_aggregate();	/* boot aggregate must be first entry */
	if (rc != 0)
		return rc;

	ima_init_policy();

	rc = ima_fs_init();
	if (rc != 0)
		return rc;

	ima_init_key_queue();

	ima_measure_critical_data("kernel_info", "kernel_version",
				  UTS_RELEASE, strlen(UTS_RELEASE), false,
				  NULL, 0);

	return rc;
}