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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  15
  16#include <linux/init.h>
  17#include <linux/scatterlist.h>
  18#include <linux/slab.h>
  19#include <linux/err.h>
  20
  21#include "ima.h"
  22
  23/* name for boot aggregate entry */
  24static const char boot_aggregate_name[] = "boot_aggregate";
  25struct tpm_chip *ima_tpm_chip;
  26
  27/* Add the boot aggregate to the IMA measurement list and extend
  28 * the PCR register.
  29 *
  30 * Calculate the boot aggregate, a SHA1 over tpm registers 0-7,
  31 * assuming a TPM chip exists, and zeroes if the TPM chip does not
  32 * exist.  Add the boot aggregate measurement to the measurement
  33 * list and extend the PCR register.
  34 *
  35 * If a tpm chip does not exist, indicate the core root of trust is
  36 * not hardware based by invalidating the aggregate PCR value.
  37 * (The aggregate PCR value is invalidated by adding one value to
  38 * the measurement list and extending the aggregate PCR value with
  39 * a different value.) Violations add a zero entry to the measurement
  40 * list and extend the aggregate PCR value with ff...ff's.
  41 */
  42static int __init ima_add_boot_aggregate(void)
  43{
  44        static const char op[] = "add_boot_aggregate";
  45        const char *audit_cause = "ENOMEM";
  46        struct ima_template_entry *entry;
  47        struct integrity_iint_cache tmp_iint, *iint = &tmp_iint;
  48        struct ima_event_data event_data = { .iint = iint,
  49                                             .filename = boot_aggregate_name };
  50        int result = -ENOMEM;
  51        int violation = 0;
  52        struct {
  53                struct ima_digest_data hdr;
  54                char digest[TPM_DIGEST_SIZE];
  55        } hash;
  56
  57        memset(iint, 0, sizeof(*iint));
  58        memset(&hash, 0, sizeof(hash));
  59        iint->ima_hash = &hash.hdr;
  60        iint->ima_hash->algo = HASH_ALGO_SHA1;
  61        iint->ima_hash->length = SHA1_DIGEST_SIZE;
  62
  63        if (ima_tpm_chip) {
  64                result = ima_calc_boot_aggregate(&hash.hdr);
  65                if (result < 0) {
  66                        audit_cause = "hashing_error";
  67                        goto err_out;
  68                }
  69        }
  70
  71        result = ima_alloc_init_template(&event_data, &entry, NULL);
  72        if (result < 0) {
  73                audit_cause = "alloc_entry";
  74                goto err_out;
  75        }
  76
  77        result = ima_store_template(entry, violation, NULL,
  78                                    boot_aggregate_name,
  79                                    CONFIG_IMA_MEASURE_PCR_IDX);
  80        if (result < 0) {
  81                ima_free_template_entry(entry);
  82                audit_cause = "store_entry";
  83                goto err_out;
  84        }
  85        return 0;
  86err_out:
  87        integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, boot_aggregate_name, op,
  88                            audit_cause, result, 0);
  89        return result;
  90}
  91
  92#ifdef CONFIG_IMA_LOAD_X509
  93void __init ima_load_x509(void)
  94{
  95        int unset_flags = ima_policy_flag & IMA_APPRAISE;
  96
  97        ima_policy_flag &= ~unset_flags;
  98        integrity_load_x509(INTEGRITY_KEYRING_IMA, CONFIG_IMA_X509_PATH);
  99        ima_policy_flag |= unset_flags;
 100}
 101#endif
 102
 103int __init ima_init(void)
 104{
 105        int rc;
 106
 107        ima_tpm_chip = tpm_default_chip();
 108        if (!ima_tpm_chip)
 109                pr_info("No TPM chip found, activating TPM-bypass!\n");
 110
 111        rc = integrity_init_keyring(INTEGRITY_KEYRING_IMA);
 112        if (rc)
 113                return rc;
 114
 115        rc = ima_init_crypto();
 116        if (rc)
 117                return rc;
 118        rc = ima_init_template();
 119        if (rc != 0)
 120                return rc;
 121
 122        /* It can be called before ima_init_digests(), it does not use TPM. */
 123        ima_load_kexec_buffer();
 124
 125        rc = ima_init_digests();
 126        if (rc != 0)
 127                return rc;
 128        rc = ima_add_boot_aggregate();  /* boot aggregate must be first entry */
 129        if (rc != 0)
 130                return rc;
 131
 132        ima_init_policy();
 133
 134        return ima_fs_init();
 135}
 136