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/err.h>
20 #include "ima.h"
21 
22 /* name for boot aggregate entry */
23 static const char *boot_aggregate_name = "boot_aggregate";
24 int ima_used_chip;
25 
26 /* Add the boot aggregate to the IMA measurement list and extend
27  * the PCR register.
28  *
29  * Calculate the boot aggregate, a SHA1 over tpm registers 0-7,
30  * assuming a TPM chip exists, and zeroes if the TPM chip does not
31  * exist.  Add the boot aggregate measurement to the measurement
32  * list and extend the PCR register.
33  *
34  * If a tpm chip does not exist, indicate the core root of trust is
35  * not hardware based by invalidating the aggregate PCR value.
36  * (The aggregate PCR value is invalidated by adding one value to
37  * the measurement list and extending the aggregate PCR value with
38  * a different value.) Violations add a zero entry to the measurement
39  * list and extend the aggregate PCR value with ff...ff's.
40  */
41 static void __init ima_add_boot_aggregate(void)
42 {
43 	struct ima_template_entry *entry;
44 	const char *op = "add_boot_aggregate";
45 	const char *audit_cause = "ENOMEM";
46 	int result = -ENOMEM;
47 	int violation = 1;
48 
49 	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
50 	if (!entry)
51 		goto err_out;
52 
53 	memset(&entry->template, 0, sizeof(entry->template));
54 	strncpy(entry->template.file_name, boot_aggregate_name,
55 		IMA_EVENT_NAME_LEN_MAX);
56 	if (ima_used_chip) {
57 		violation = 0;
58 		result = ima_calc_boot_aggregate(entry->template.digest);
59 		if (result < 0) {
60 			audit_cause = "hashing_error";
61 			kfree(entry);
62 			goto err_out;
63 		}
64 	}
65 	result = ima_store_template(entry, violation, NULL);
66 	if (result < 0)
67 		kfree(entry);
68 	return;
69 err_out:
70 	integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, boot_aggregate_name, op,
71 			    audit_cause, result, 0);
72 }
73 
74 int __init ima_init(void)
75 {
76 	u8 pcr_i[IMA_DIGEST_SIZE];
77 	int rc;
78 
79 	ima_used_chip = 0;
80 	rc = tpm_pcr_read(TPM_ANY_NUM, 0, pcr_i);
81 	if (rc == 0)
82 		ima_used_chip = 1;
83 
84 	if (!ima_used_chip)
85 		pr_info("No TPM chip found, activating TPM-bypass!\n");
86 
87 	ima_add_boot_aggregate();	/* boot aggregate must be first entry */
88 	ima_init_policy();
89 
90 	return ima_fs_init();
91 }
92 
93 void __exit ima_cleanup(void)
94 {
95 	ima_fs_cleanup();
96 }
97