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