LXR linux/security/integrity/ima/ima

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Copyright (C) 2005,2006,2007,2008 IBM Corporation
   4 *
   5 * Authors:
   6 * Reiner Sailer      <sailer@watson.ibm.com>
   7 * Leendert van Doorn <leendert@watson.ibm.com>
   8 * Mimi Zohar         <zohar@us.ibm.com>
   9 *
  10 * File: ima_init.c
  11 *             initialization and cleanup functions
  12 */
  13
  14#include <linux/init.h>
  15#include <linux/scatterlist.h>
  16#include <linux/slab.h>
  17#include <linux/err.h>
  18
  19#include "ima.h"
  20
  21/* name for boot aggregate entry */
  22const char boot_aggregate_name[] = "boot_aggregate";
  23struct tpm_chip *ima_tpm_chip;
  24
  25/* Add the boot aggregate to the IMA measurement list and extend
  26 * the PCR register.
  27 *
  28 * Calculate the boot aggregate, a hash over tpm registers 0-7,
  29 * assuming a TPM chip exists, and zeroes if the TPM chip does not
  30 * exist.  Add the boot aggregate measurement to the measurement
  31 * list and extend the PCR register.
  32 *
  33 * If a tpm chip does not exist, indicate the core root of trust is
  34 * not hardware based by invalidating the aggregate PCR value.
  35 * (The aggregate PCR value is invalidated by adding one value to
  36 * the measurement list and extending the aggregate PCR value with
  37 * a different value.) Violations add a zero entry to the measurement
  38 * list and extend the aggregate PCR value with ff...ff's.
  39 */
  40static int __init ima_add_boot_aggregate(void)
  41{
  42        static const char op[] = "add_boot_aggregate";
  43        const char *audit_cause = "ENOMEM";
  44        struct ima_template_entry *entry;
  45        struct integrity_iint_cache tmp_iint, *iint = &tmp_iint;
  46        struct ima_event_data event_data = { .iint = iint,
  47                                             .filename = boot_aggregate_name };
  48        int result = -ENOMEM;
  49        int violation = 0;
  50        struct {
  51                struct ima_digest_data hdr;
  52                char digest[TPM_MAX_DIGEST_SIZE];
  53        } hash;
  54
  55        memset(iint, 0, sizeof(*iint));
  56        memset(&hash, 0, sizeof(hash));
  57        iint->ima_hash = &hash.hdr;
  58        iint->ima_hash->algo = ima_hash_algo;
  59        iint->ima_hash->length = hash_digest_size[ima_hash_algo];
  60
  61        /*
  62         * With TPM 2.0 hash agility, TPM chips could support multiple TPM
  63         * PCR banks, allowing firmware to configure and enable different
  64         * banks.  The SHA1 bank is not necessarily enabled.
  65         *
  66         * Use the same hash algorithm for reading the TPM PCRs as for
  67         * calculating the boot aggregate digest.  Preference is given to
  68         * the configured IMA default hash algorithm.  Otherwise, use the
  69         * TCG required banks - SHA256 for TPM 2.0, SHA1 for TPM 1.2.
  70         * Ultimately select SHA1 also for TPM 2.0 if the SHA256 PCR bank
  71         * is not found.
  72         */
  73        if (ima_tpm_chip) {
  74                result = ima_calc_boot_aggregate(&hash.hdr);
  75                if (result < 0) {
  76                        audit_cause = "hashing_error";
  77                        goto err_out;
  78                }
  79        }
  80
  81        result = ima_alloc_init_template(&event_data, &entry, NULL);
  82        if (result < 0) {
  83                audit_cause = "alloc_entry";
  84                goto err_out;
  85        }
  86
  87        result = ima_store_template(entry, violation, NULL,
  88                                    boot_aggregate_name,
  89                                    CONFIG_IMA_MEASURE_PCR_IDX);
  90        if (result < 0) {
  91                ima_free_template_entry(entry);
  92                audit_cause = "store_entry";
  93                goto err_out;
  94        }
  95        return 0;
  96err_out:
  97        integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, boot_aggregate_name, op,
  98                            audit_cause, result, 0);
  99        return result;
 100}
 101
 102#ifdef CONFIG_IMA_LOAD_X509
 103void __init ima_load_x509(void)
 104{
 105        int unset_flags = ima_policy_flag & IMA_APPRAISE;
 106
 107        ima_policy_flag &= ~unset_flags;
 108        integrity_load_x509(INTEGRITY_KEYRING_IMA, CONFIG_IMA_X509_PATH);
 109        ima_policy_flag |= unset_flags;
 110}
 111#endif
 112
 113int __init ima_init(void)
 114{
 115        int rc;
 116
 117        ima_tpm_chip = tpm_default_chip();
 118        if (!ima_tpm_chip)
 119                pr_info("No TPM chip found, activating TPM-bypass!\n");
 120
 121        rc = integrity_init_keyring(INTEGRITY_KEYRING_IMA);
 122        if (rc)
 123                return rc;
 124
 125        rc = ima_init_crypto();
 126        if (rc)
 127                return rc;
 128        rc = ima_init_template();
 129        if (rc != 0)
 130                return rc;
 131
 132        /* It can be called before ima_init_digests(), it does not use TPM. */
 133        ima_load_kexec_buffer();
 134
 135        rc = ima_init_digests();
 136        if (rc != 0)
 137                return rc;
 138        rc = ima_add_boot_aggregate();  /* boot aggregate must be first entry */
 139        if (rc != 0)
 140                return rc;
 141
 142        ima_init_policy();
 143
 144        rc = ima_fs_init();
 145        if (rc != 0)
 146                return rc;
 147
 148        ima_init_key_queue();
 149
 150        return rc;
 151}
 152