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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15 
16 #include <linux/init.h>
17 #include <linux/scatterlist.h>
18 #include <linux/slab.h>
19 #include <linux/err.h>
20 
21 #include "ima.h"
22 
23 /* name for boot aggregate entry */
24 static const char boot_aggregate_name[] = "boot_aggregate";
25 struct 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 SHA1 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  */
42 static 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 integrity_iint_cache tmp_iint, *iint = &tmp_iint;
48 	struct ima_event_data event_data = { .iint = iint,
49 					     .filename = boot_aggregate_name };
50 	int result = -ENOMEM;
51 	int violation = 0;
52 	struct {
53 		struct ima_digest_data hdr;
54 		char digest[TPM_DIGEST_SIZE];
55 	} hash;
56 
57 	memset(iint, 0, sizeof(*iint));
58 	memset(&hash, 0, sizeof(hash));
59 	iint->ima_hash = &hash.hdr;
60 	iint->ima_hash->algo = HASH_ALGO_SHA1;
61 	iint->ima_hash->length = SHA1_DIGEST_SIZE;
62 
63 	if (ima_tpm_chip) {
64 		result = ima_calc_boot_aggregate(&hash.hdr);
65 		if (result < 0) {
66 			audit_cause = "hashing_error";
67 			goto err_out;
68 		}
69 	}
70 
71 	result = ima_alloc_init_template(&event_data, &entry, NULL);
72 	if (result < 0) {
73 		audit_cause = "alloc_entry";
74 		goto err_out;
75 	}
76 
77 	result = ima_store_template(entry, violation, NULL,
78 				    boot_aggregate_name,
79 				    CONFIG_IMA_MEASURE_PCR_IDX);
80 	if (result < 0) {
81 		ima_free_template_entry(entry);
82 		audit_cause = "store_entry";
83 		goto err_out;
84 	}
85 	return 0;
86 err_out:
87 	integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, boot_aggregate_name, op,
88 			    audit_cause, result, 0);
89 	return result;
90 }
91 
92 #ifdef CONFIG_IMA_LOAD_X509
93 void __init ima_load_x509(void)
94 {
95 	int unset_flags = ima_policy_flag & IMA_APPRAISE;
96 
97 	ima_policy_flag &= ~unset_flags;
98 	integrity_load_x509(INTEGRITY_KEYRING_IMA, CONFIG_IMA_X509_PATH);
99 	ima_policy_flag |= unset_flags;
100 }
101 #endif
102 
103 int __init ima_init(void)
104 {
105 	int rc;
106 
107 	ima_tpm_chip = tpm_default_chip();
108 	if (!ima_tpm_chip)
109 		pr_info("No TPM chip found, activating TPM-bypass!\n");
110 
111 	rc = integrity_init_keyring(INTEGRITY_KEYRING_IMA);
112 	if (rc)
113 		return rc;
114 
115 	rc = ima_init_crypto();
116 	if (rc)
117 		return rc;
118 	rc = ima_init_template();
119 	if (rc != 0)
120 		return rc;
121 
122 	/* It can be called before ima_init_digests(), it does not use TPM. */
123 	ima_load_kexec_buffer();
124 
125 	rc = ima_init_digests();
126 	if (rc != 0)
127 		return rc;
128 	rc = ima_add_boot_aggregate();	/* boot aggregate must be first entry */
129 	if (rc != 0)
130 		return rc;
131 
132 	ima_init_policy();
133 
134 	return ima_fs_init();
135 }
136