148 lines
4.0 KiB
C
148 lines
4.0 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2005,2006,2007,2008 IBM Corporation
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*
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* Authors:
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* Reiner Sailer <sailer@watson.ibm.com>
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* Leendert van Doorn <leendert@watson.ibm.com>
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* Mimi Zohar <zohar@us.ibm.com>
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*
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* File: ima_init.c
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* initialization and cleanup functions
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/init.h>
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#include <linux/scatterlist.h>
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#include <linux/slab.h>
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#include <linux/err.h>
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#include "ima.h"
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/* name for boot aggregate entry */
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const char boot_aggregate_name[] = "boot_aggregate";
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struct tpm_chip *ima_tpm_chip;
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/* Add the boot aggregate to the IMA measurement list and extend
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* the PCR register.
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*
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* Calculate the boot aggregate, a hash over tpm registers 0-7,
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* assuming a TPM chip exists, and zeroes if the TPM chip does not
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* exist. Add the boot aggregate measurement to the measurement
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* list and extend the PCR register.
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*
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* If a tpm chip does not exist, indicate the core root of trust is
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* not hardware based by invalidating the aggregate PCR value.
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* (The aggregate PCR value is invalidated by adding one value to
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* the measurement list and extending the aggregate PCR value with
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* a different value.) Violations add a zero entry to the measurement
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* list and extend the aggregate PCR value with ff...ff's.
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*/
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static int __init ima_add_boot_aggregate(void)
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{
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static const char op[] = "add_boot_aggregate";
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const char *audit_cause = "ENOMEM";
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struct ima_template_entry *entry;
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struct integrity_iint_cache tmp_iint, *iint = &tmp_iint;
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struct ima_event_data event_data = { .iint = iint,
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.filename = boot_aggregate_name };
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int result = -ENOMEM;
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int violation = 0;
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struct {
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struct ima_digest_data hdr;
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char digest[TPM_MAX_DIGEST_SIZE];
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} hash;
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memset(iint, 0, sizeof(*iint));
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memset(&hash, 0, sizeof(hash));
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iint->ima_hash = &hash.hdr;
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iint->ima_hash->algo = ima_hash_algo;
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iint->ima_hash->length = hash_digest_size[ima_hash_algo];
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/*
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* With TPM 2.0 hash agility, TPM chips could support multiple TPM
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* PCR banks, allowing firmware to configure and enable different
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* banks. The SHA1 bank is not necessarily enabled.
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*
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* Use the same hash algorithm for reading the TPM PCRs as for
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* calculating the boot aggregate digest. Preference is given to
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* the configured IMA default hash algorithm. Otherwise, use the
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* TCG required banks - SHA256 for TPM 2.0, SHA1 for TPM 1.2.
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* Ultimately select SHA1 also for TPM 2.0 if the SHA256 PCR bank
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* is not found.
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*/
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if (ima_tpm_chip) {
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result = ima_calc_boot_aggregate(&hash.hdr);
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if (result < 0) {
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audit_cause = "hashing_error";
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goto err_out;
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}
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}
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result = ima_alloc_init_template(&event_data, &entry, NULL);
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if (result < 0) {
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audit_cause = "alloc_entry";
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goto err_out;
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}
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result = ima_store_template(entry, violation, NULL,
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boot_aggregate_name,
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CONFIG_IMA_MEASURE_PCR_IDX);
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if (result < 0) {
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ima_free_template_entry(entry);
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audit_cause = "store_entry";
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goto err_out;
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}
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return 0;
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err_out:
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integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, boot_aggregate_name, op,
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audit_cause, result, 0);
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return result;
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}
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#ifdef CONFIG_IMA_LOAD_X509
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void __init ima_load_x509(void)
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{
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int unset_flags = ima_policy_flag & IMA_APPRAISE;
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ima_policy_flag &= ~unset_flags;
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integrity_load_x509(INTEGRITY_KEYRING_IMA, CONFIG_IMA_X509_PATH);
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ima_policy_flag |= unset_flags;
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}
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#endif
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int __init ima_init(void)
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{
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int rc;
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ima_tpm_chip = tpm_default_chip();
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if (!ima_tpm_chip)
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pr_info("No TPM chip found, activating TPM-bypass!\n");
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rc = integrity_init_keyring(INTEGRITY_KEYRING_IMA);
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if (rc)
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return rc;
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rc = ima_init_crypto();
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if (rc)
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return rc;
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rc = ima_init_template();
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if (rc != 0)
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return rc;
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/* It can be called before ima_init_digests(), it does not use TPM. */
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ima_load_kexec_buffer();
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rc = ima_init_digests();
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if (rc != 0)
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return rc;
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rc = ima_add_boot_aggregate(); /* boot aggregate must be first entry */
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if (rc != 0)
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return rc;
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ima_init_policy();
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return ima_fs_init();
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}
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