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 #include <crypto/hash_info.h>
25 #include "ima.h"
26 
27 #ifdef CONFIG_IMA_X509_PATH
28 #define IMA_X509_PATH	CONFIG_IMA_X509_PATH
29 #else
30 #define IMA_X509_PATH	"/etc/keys/x509_ima.der"
31 #endif
32 
33 /* name for boot aggregate entry */
34 static const char *boot_aggregate_name = "boot_aggregate";
35 int ima_used_chip;
36 
37 /* Add the boot aggregate to the IMA measurement list and extend
38  * the PCR register.
39  *
40  * Calculate the boot aggregate, a SHA1 over tpm registers 0-7,
41  * assuming a TPM chip exists, and zeroes if the TPM chip does not
42  * exist.  Add the boot aggregate measurement to the measurement
43  * list and extend the PCR register.
44  *
45  * If a tpm chip does not exist, indicate the core root of trust is
46  * not hardware based by invalidating the aggregate PCR value.
47  * (The aggregate PCR value is invalidated by adding one value to
48  * the measurement list and extending the aggregate PCR value with
49  * a different value.) Violations add a zero entry to the measurement
50  * list and extend the aggregate PCR value with ff...ff's.
51  */
52 static int __init ima_add_boot_aggregate(void)
53 {
54 	static const char op[] = "add_boot_aggregate";
55 	const char *audit_cause = "ENOMEM";
56 	struct ima_template_entry *entry;
57 	struct integrity_iint_cache tmp_iint, *iint = &tmp_iint;
58 	int result = -ENOMEM;
59 	int violation = 0;
60 	struct {
61 		struct ima_digest_data hdr;
62 		char digest[TPM_DIGEST_SIZE];
63 	} hash;
64 
65 	memset(iint, 0, sizeof(*iint));
66 	memset(&hash, 0, sizeof(hash));
67 	iint->ima_hash = &hash.hdr;
68 	iint->ima_hash->algo = HASH_ALGO_SHA1;
69 	iint->ima_hash->length = SHA1_DIGEST_SIZE;
70 
71 	if (ima_used_chip) {
72 		result = ima_calc_boot_aggregate(&hash.hdr);
73 		if (result < 0) {
74 			audit_cause = "hashing_error";
75 			goto err_out;
76 		}
77 	}
78 
79 	result = ima_alloc_init_template(iint, NULL, boot_aggregate_name,
80 					 NULL, 0, &entry);
81 	if (result < 0) {
82 		audit_cause = "alloc_entry";
83 		goto err_out;
84 	}
85 
86 	result = ima_store_template(entry, violation, NULL,
87 				    boot_aggregate_name);
88 	if (result < 0) {
89 		ima_free_template_entry(entry);
90 		audit_cause = "store_entry";
91 		goto err_out;
92 	}
93 	return 0;
94 err_out:
95 	integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, boot_aggregate_name, op,
96 			    audit_cause, result, 0);
97 	return result;
98 }
99 
100 #ifdef CONFIG_IMA_LOAD_X509
101 void __init ima_load_x509(void)
102 {
103 	int unset_flags = ima_policy_flag & IMA_APPRAISE;
104 
105 	ima_policy_flag &= ~unset_flags;
106 	integrity_load_x509(INTEGRITY_KEYRING_IMA, IMA_X509_PATH);
107 	ima_policy_flag |= unset_flags;
108 }
109 #endif
110 
111 int __init ima_init(void)
112 {
113 	u8 pcr_i[TPM_DIGEST_SIZE];
114 	int rc;
115 
116 	ima_used_chip = 0;
117 	rc = tpm_pcr_read(TPM_ANY_NUM, 0, pcr_i);
118 	if (rc == 0)
119 		ima_used_chip = 1;
120 
121 	if (!ima_used_chip)
122 		pr_info("No TPM chip found, activating TPM-bypass!\n");
123 
124 	rc = ima_init_keyring(INTEGRITY_KEYRING_IMA);
125 	if (rc)
126 		return rc;
127 
128 	rc = ima_init_crypto();
129 	if (rc)
130 		return rc;
131 	rc = ima_init_template();
132 	if (rc != 0)
133 		return rc;
134 
135 	rc = ima_add_boot_aggregate();	/* boot aggregate must be first entry */
136 	if (rc != 0)
137 		return rc;
138 
139 	ima_init_policy();
140 
141 	return ima_fs_init();
142 }
143