1 /*
2  * Copyright (C) 2005,2006,2007,2008 IBM Corporation
3  *
4  * Authors:
5  * Reiner Sailer      <sailer@watson.ibm.com>
6  * Leendert van Doorn <leendert@watson.ibm.com>
7  * Mimi Zohar         <zohar@us.ibm.com>
8  *
9  * This program is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU General Public License as
11  * published by the Free Software Foundation, version 2 of the
12  * License.
13  *
14  * File: ima_init.c
15  *             initialization and cleanup functions
16  */
17 
18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
19 
20 #include <linux/module.h>
21 #include <linux/scatterlist.h>
22 #include <linux/slab.h>
23 #include <linux/err.h>
24 
25 #include "ima.h"
26 
27 /* name for boot aggregate entry */
28 static const char *boot_aggregate_name = "boot_aggregate";
29 int ima_used_chip;
30 
31 /* Add the boot aggregate to the IMA measurement list and extend
32  * the PCR register.
33  *
34  * Calculate the boot aggregate, a SHA1 over tpm registers 0-7,
35  * assuming a TPM chip exists, and zeroes if the TPM chip does not
36  * exist.  Add the boot aggregate measurement to the measurement
37  * list and extend the PCR register.
38  *
39  * If a tpm chip does not exist, indicate the core root of trust is
40  * not hardware based by invalidating the aggregate PCR value.
41  * (The aggregate PCR value is invalidated by adding one value to
42  * the measurement list and extending the aggregate PCR value with
43  * a different value.) Violations add a zero entry to the measurement
44  * list and extend the aggregate PCR value with ff...ff's.
45  */
46 static int __init ima_add_boot_aggregate(void)
47 {
48 	static const char op[] = "add_boot_aggregate";
49 	const char *audit_cause = "ENOMEM";
50 	struct ima_template_entry *entry;
51 	struct integrity_iint_cache tmp_iint, *iint = &tmp_iint;
52 	struct ima_event_data event_data = {iint, NULL, boot_aggregate_name,
53 					    NULL, 0, NULL};
54 	int result = -ENOMEM;
55 	int violation = 0;
56 	struct {
57 		struct ima_digest_data hdr;
58 		char digest[TPM_DIGEST_SIZE];
59 	} hash;
60 
61 	memset(iint, 0, sizeof(*iint));
62 	memset(&hash, 0, sizeof(hash));
63 	iint->ima_hash = &hash.hdr;
64 	iint->ima_hash->algo = HASH_ALGO_SHA1;
65 	iint->ima_hash->length = SHA1_DIGEST_SIZE;
66 
67 	if (ima_used_chip) {
68 		result = ima_calc_boot_aggregate(&hash.hdr);
69 		if (result < 0) {
70 			audit_cause = "hashing_error";
71 			goto err_out;
72 		}
73 	}
74 
75 	result = ima_alloc_init_template(&event_data, &entry);
76 	if (result < 0) {
77 		audit_cause = "alloc_entry";
78 		goto err_out;
79 	}
80 
81 	result = ima_store_template(entry, violation, NULL,
82 				    boot_aggregate_name,
83 				    CONFIG_IMA_MEASURE_PCR_IDX);
84 	if (result < 0) {
85 		ima_free_template_entry(entry);
86 		audit_cause = "store_entry";
87 		goto err_out;
88 	}
89 	return 0;
90 err_out:
91 	integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, boot_aggregate_name, op,
92 			    audit_cause, result, 0);
93 	return result;
94 }
95 
96 #ifdef CONFIG_IMA_LOAD_X509
97 void __init ima_load_x509(void)
98 {
99 	int unset_flags = ima_policy_flag & IMA_APPRAISE;
100 
101 	ima_policy_flag &= ~unset_flags;
102 	integrity_load_x509(INTEGRITY_KEYRING_IMA, CONFIG_IMA_X509_PATH);
103 	ima_policy_flag |= unset_flags;
104 }
105 #endif
106 
107 int __init ima_init(void)
108 {
109 	u8 pcr_i[TPM_DIGEST_SIZE];
110 	int rc;
111 
112 	ima_used_chip = 0;
113 	rc = tpm_pcr_read(TPM_ANY_NUM, 0, pcr_i);
114 	if (rc == 0)
115 		ima_used_chip = 1;
116 
117 	if (!ima_used_chip)
118 		pr_info("No TPM chip found, activating TPM-bypass!\n");
119 
120 	rc = integrity_init_keyring(INTEGRITY_KEYRING_IMA);
121 	if (rc)
122 		return rc;
123 
124 	rc = ima_init_crypto();
125 	if (rc)
126 		return rc;
127 	rc = ima_init_template();
128 	if (rc != 0)
129 		return rc;
130 
131 	rc = ima_add_boot_aggregate();	/* boot aggregate must be first entry */
132 	if (rc != 0)
133 		return rc;
134 
135 	ima_init_policy();
136 
137 	return ima_fs_init();
138 }
139