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authorMimi Zohar <zohar@linux.vnet.ibm.com>2009-02-04 09:06:58 -0500
committerJames Morris <jmorris@namei.org>2009-02-05 17:05:30 -0500
commit3323eec921efd815178a23107ab63588c605c0b2 (patch)
treebc9e9714ac4881ebc515c1bd155674c52c356d6a /security/integrity/ima/ima_init.c
parent6146f0d5e47ca4047ffded0fb79b6c25359b386c (diff)
integrity: IMA as an integrity service provider
IMA provides hardware (TPM) based measurement and attestation for file measurements. As the Trusted Computing (TPM) model requires, IMA measures all files before they are accessed in any way (on the integrity_bprm_check, integrity_path_check and integrity_file_mmap hooks), and commits the measurements to the TPM. Once added to the TPM, measurements can not be removed. In addition, IMA maintains a list of these file measurements, which can be used to validate the aggregate value stored in the TPM. The TPM can sign these measurements, and thus the system can prove, to itself and to a third party, the system's integrity in a way that cannot be circumvented by malicious or compromised software. - alloc ima_template_entry before calling ima_store_template() - log ima_add_boot_aggregate() failure - removed unused IMA_TEMPLATE_NAME_LEN - replaced hard coded string length with #define name Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'security/integrity/ima/ima_init.c')
-rw-r--r--security/integrity/ima/ima_init.c90
1 files changed, 90 insertions, 0 deletions
diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c
new file mode 100644
index 00000000000..e0f02e328d7
--- /dev/null
+++ b/security/integrity/ima/ima_init.c
@@ -0,0 +1,90 @@
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 */
23static char *boot_aggregate_name = "boot_aggregate";
24int 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 */
41static void 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;
69err_out:
70 integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, boot_aggregate_name, op,
71 audit_cause, result, 0);
72}
73
74int 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 return 0;
90}