// 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
 */

#include <linux/init.h>
#include <linux/scatterlist.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/ima.h>
#include <generated/utsrelease.h>

#include "ima.h"

/* name for boot aggregate entry */
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 ima_iint_cache tmp_iint, *iint = &tmp_iint;
        struct ima_event_data event_data = { .iint = iint,
                                             .filename = boot_aggregate_name };
        struct ima_max_digest_data hash;
        struct ima_digest_data *hash_hdr = container_of(&hash.hdr,
                                                struct ima_digest_data, hdr);
        int result = -ENOMEM;
        int violation = 0;

        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);

        /* load also EVM key to avoid appraisal */
        evm_load_x509();

        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();

        rc = ima_fs_init();
        if (rc != 0)
                return rc;

        ima_init_key_queue();

        ima_init_reboot_notifier();

        ima_measure_critical_data("kernel_info", "kernel_version",
                                  UTS_RELEASE, strlen(UTS_RELEASE), false,
                                  NULL, 0);

        return rc;
}