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 #include <linux/module.h>
18 #include <linux/scatterlist.h>
19 #include <linux/slab.h>
20 #include <linux/err.h>
21 #include "ima.h"
22 
23 /* name for boot aggregate entry */
24 static const char *boot_aggregate_name = "boot_aggregate";
25 int ima_used_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 void __init ima_add_boot_aggregate(void)
43 {
44 	struct ima_template_entry *entry;
45 	const char *op = "add_boot_aggregate";
46 	const char *audit_cause = "ENOMEM";
47 	int result = -ENOMEM;
48 	int violation = 1;
49 
50 	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
51 	if (!entry)
52 		goto err_out;
53 
54 	memset(&entry->template, 0, sizeof(entry->template));
55 	strncpy(entry->template.file_name, boot_aggregate_name,
56 		IMA_EVENT_NAME_LEN_MAX);
57 	if (ima_used_chip) {
58 		violation = 0;
59 		result = ima_calc_boot_aggregate(entry->template.digest);
60 		if (result < 0) {
61 			audit_cause = "hashing_error";
62 			kfree(entry);
63 			goto err_out;
64 		}
65 	}
66 	result = ima_store_template(entry, violation, NULL);
67 	if (result < 0)
68 		kfree(entry);
69 	return;
70 err_out:
71 	integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, boot_aggregate_name, op,
72 			    audit_cause, result, 0);
73 }
74 
75 int __init ima_init(void)
76 {
77 	u8 pcr_i[IMA_DIGEST_SIZE];
78 	int rc;
79 
80 	ima_used_chip = 0;
81 	rc = tpm_pcr_read(TPM_ANY_NUM, 0, pcr_i);
82 	if (rc == 0)
83 		ima_used_chip = 1;
84 
85 	if (!ima_used_chip)
86 		pr_info("IMA: No TPM chip found, activating TPM-bypass!\n");
87 
88 	ima_add_boot_aggregate();	/* boot aggregate must be first entry */
89 	ima_init_policy();
90 
91 	return ima_fs_init();
92 }
93 
94 void __exit ima_cleanup(void)
95 {
96 	ima_fs_cleanup();
97 }
98