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/*
* Copyright (C) 2005,2006,2007,2008 IBM Corporation
*
* Authors:
* Reiner Sailer <sailer@watson.ibm.com>
* Leendert van Doorn <leendert@watson.ibm.com>
* Mimi Zohar <zohar@us.ibm.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation, version 2 of the
* License.
*
* File: ima_init.c
* initialization and cleanup functions
*/
#include <linux/module.h>
#include <linux/scatterlist.h>
#include <linux/err.h>
#include "ima.h"
/* name for boot aggregate entry */
static char *boot_aggregate_name = "boot_aggregate";
int ima_used_chip;
/* Add the boot aggregate to the IMA measurement list and extend
* the PCR register.
*
* Calculate the boot aggregate, a SHA1 over tpm registers 0-7,
* assuming a TPM chip exists, and zeroes if the TPM chip does not
* exist. Add the boot aggregate measurement to the measurement
* list and extend the PCR register.
*
* If a tpm chip does not exist, indicate the core root of trust is
* not hardware based by invalidating the aggregate PCR value.
* (The aggregate PCR value is invalidated by adding one value to
* the measurement list and extending the aggregate PCR value with
* a different value.) Violations add a zero entry to the measurement
* list and extend the aggregate PCR value with ff...ff's.
*/
static void ima_add_boot_aggregate(void)
{
struct ima_template_entry *entry;
const char *op = "add_boot_aggregate";
const char *audit_cause = "ENOMEM";
int result = -ENOMEM;
int violation = 1;
entry = kmalloc(sizeof(*entry), GFP_KERNEL);
if (!entry)
goto err_out;
memset(&entry->template, 0, sizeof(entry->template));
strncpy(entry->template.file_name, boot_aggregate_name,
IMA_EVENT_NAME_LEN_MAX);
if (ima_used_chip) {
violation = 0;
result = ima_calc_boot_aggregate(entry->template.digest);
if (result < 0) {
audit_cause = "hashing_error";
kfree(entry);
goto err_out;
}
}
result = ima_store_template(entry, violation, NULL);
if (result < 0)
kfree(entry);
return;
err_out:
integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, boot_aggregate_name, op,
audit_cause, result, 0);
}
int ima_init(void)
{
u8 pcr_i[IMA_DIGEST_SIZE];
int rc;
ima_used_chip = 0;
rc = tpm_pcr_read(TPM_ANY_NUM, 0, pcr_i);
if (rc == 0)
ima_used_chip = 1;
if (!ima_used_chip)
pr_info("No TPM chip found, activating TPM-bypass!\n");
ima_add_boot_aggregate(); /* boot aggregate must be first entry */
ima_init_policy();
return 0;
}
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