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// SPDX-License-Identifier: GPL-2.0-only
/*
* 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>
*
* File: ima_init.c
* initialization and cleanup functions
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/init.h>
#include <linux/scatterlist.h>
#include <linux/slab.h>
#include <linux/err.h>
#include "ima.h"
/* name for boot aggregate entry */
static const char boot_aggregate_name[] = "boot_aggregate";
struct tpm_chip *ima_tpm_chip;
/* Add the boot aggregate to the IMA measurement list and extend
* the PCR register.
*
* Calculate the boot aggregate, a hash 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 int __init ima_add_boot_aggregate(void)
{
static const char op[] = "add_boot_aggregate";
const char *audit_cause = "ENOMEM";
struct ima_template_entry *entry;
struct integrity_iint_cache tmp_iint, *iint = &tmp_iint;
struct ima_event_data event_data = { .iint = iint,
.filename = boot_aggregate_name };
int result = -ENOMEM;
int violation = 0;
struct {
struct ima_digest_data hdr;
char digest[TPM_MAX_DIGEST_SIZE];
} hash;
memset(iint, 0, sizeof(*iint));
memset(&hash, 0, sizeof(hash));
iint->ima_hash = &hash.hdr;
iint->ima_hash->algo = ima_hash_algo;
iint->ima_hash->length = hash_digest_size[ima_hash_algo];
/*
* With TPM 2.0 hash agility, TPM chips could support multiple TPM
* PCR banks, allowing firmware to configure and enable different
* banks. The SHA1 bank is not necessarily enabled.
*
* Use the same hash algorithm for reading the TPM PCRs as for
* calculating the boot aggregate digest. Preference is given to
* the configured IMA default hash algorithm. Otherwise, use the
* TCG required banks - SHA256 for TPM 2.0, SHA1 for TPM 1.2.
* Ultimately select SHA1 also for TPM 2.0 if the SHA256 PCR bank
* is not found.
*/
if (ima_tpm_chip) {
result = ima_calc_boot_aggregate(&hash.hdr);
if (result < 0) {
audit_cause = "hashing_error";
goto err_out;
}
}
result = ima_alloc_init_template(&event_data, &entry, NULL);
if (result < 0) {
audit_cause = "alloc_entry";
goto err_out;
}
result = ima_store_template(entry, violation, NULL,
boot_aggregate_name,
CONFIG_IMA_MEASURE_PCR_IDX);
if (result < 0) {
ima_free_template_entry(entry);
audit_cause = "store_entry";
goto err_out;
}
return 0;
err_out:
integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, boot_aggregate_name, op,
audit_cause, result, 0);
return result;
}
#ifdef CONFIG_IMA_LOAD_X509
void __init ima_load_x509(void)
{
int unset_flags = ima_policy_flag & IMA_APPRAISE;
ima_policy_flag &= ~unset_flags;
integrity_load_x509(INTEGRITY_KEYRING_IMA, CONFIG_IMA_X509_PATH);
ima_policy_flag |= unset_flags;
}
#endif
int __init ima_init(void)
{
int rc;
ima_tpm_chip = tpm_default_chip();
if (!ima_tpm_chip)
pr_info("No TPM chip found, activating TPM-bypass!\n");
rc = integrity_init_keyring(INTEGRITY_KEYRING_IMA);
if (rc)
return rc;
rc = ima_init_crypto();
if (rc)
return rc;
rc = ima_init_template();
if (rc != 0)
return rc;
/* It can be called before ima_init_digests(), it does not use TPM. */
ima_load_kexec_buffer();
rc = ima_init_digests();
if (rc != 0)
return rc;
rc = ima_add_boot_aggregate(); /* boot aggregate must be first entry */
if (rc != 0)
return rc;
ima_init_policy();
return ima_fs_init();
}
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