ima_init.c

  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	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;
 97err_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
104void __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
118int __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_init_reboot_notifier();
156
157	ima_measure_critical_data("kernel_info", "kernel_version",
158				  UTS_RELEASE, strlen(UTS_RELEASE), false,
159				  NULL, 0);
160
161	return rc;
162}