LXR linux/security/integrity/ima/ima

   1/*
   2 * Copyright (C) 2005,2006,2007,2008 IBM Corporation
   3 *
   4 * Authors:
   5 * Reiner Sailer      <sailer@watson.ibm.com>
   6 * Leendert van Doorn <leendert@watson.ibm.com>
   7 * Mimi Zohar         <zohar@us.ibm.com>
   8 *
   9 * This program is free software; you can redistribute it and/or
  10 * modify it under the terms of the GNU General Public License as
  11 * published by the Free Software Foundation, version 2 of the
  12 * License.
  13 *
  14 * File: ima_init.c
  15 *             initialization and cleanup functions
  16 */
  17
  18#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  19
  20#include <linux/module.h>
  21#include <linux/scatterlist.h>
  22#include <linux/slab.h>
  23#include <linux/err.h>
  24
  25#include "ima.h"
  26
  27/* name for boot aggregate entry */
  28static const char *boot_aggregate_name = "boot_aggregate";
  29int ima_used_chip;
  30
  31/* Add the boot aggregate to the IMA measurement list and extend
  32 * the PCR register.
  33 *
  34 * Calculate the boot aggregate, a SHA1 over tpm registers 0-7,
  35 * assuming a TPM chip exists, and zeroes if the TPM chip does not
  36 * exist.  Add the boot aggregate measurement to the measurement
  37 * list and extend the PCR register.
  38 *
  39 * If a tpm chip does not exist, indicate the core root of trust is
  40 * not hardware based by invalidating the aggregate PCR value.
  41 * (The aggregate PCR value is invalidated by adding one value to
  42 * the measurement list and extending the aggregate PCR value with
  43 * a different value.) Violations add a zero entry to the measurement
  44 * list and extend the aggregate PCR value with ff...ff's.
  45 */
  46static int __init ima_add_boot_aggregate(void)
  47{
  48        static const char op[] = "add_boot_aggregate";
  49        const char *audit_cause = "ENOMEM";
  50        struct ima_template_entry *entry;
  51        struct integrity_iint_cache tmp_iint, *iint = &tmp_iint;
  52        struct ima_event_data event_data = {iint, NULL, boot_aggregate_name,
  53                                            NULL, 0, NULL};
  54        int result = -ENOMEM;
  55        int violation = 0;
  56        struct {
  57                struct ima_digest_data hdr;
  58                char digest[TPM_DIGEST_SIZE];
  59        } hash;
  60
  61        memset(iint, 0, sizeof(*iint));
  62        memset(&hash, 0, sizeof(hash));
  63        iint->ima_hash = &hash.hdr;
  64        iint->ima_hash->algo = HASH_ALGO_SHA1;
  65        iint->ima_hash->length = SHA1_DIGEST_SIZE;
  66
  67        if (ima_used_chip) {
  68                result = ima_calc_boot_aggregate(&hash.hdr);
  69                if (result < 0) {
  70                        audit_cause = "hashing_error";
  71                        goto err_out;
  72                }
  73        }
  74
  75        result = ima_alloc_init_template(&event_data, &entry);
  76        if (result < 0) {
  77                audit_cause = "alloc_entry";
  78                goto err_out;
  79        }
  80
  81        result = ima_store_template(entry, violation, NULL,
  82                                    boot_aggregate_name);
  83        if (result < 0) {
  84                ima_free_template_entry(entry);
  85                audit_cause = "store_entry";
  86                goto err_out;
  87        }
  88        return 0;
  89err_out:
  90        integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, boot_aggregate_name, op,
  91                            audit_cause, result, 0);
  92        return result;
  93}
  94
  95#ifdef CONFIG_IMA_LOAD_X509
  96void __init ima_load_x509(void)
  97{
  98        int unset_flags = ima_policy_flag & IMA_APPRAISE;
  99
 100        ima_policy_flag &= ~unset_flags;
 101        integrity_load_x509(INTEGRITY_KEYRING_IMA, CONFIG_IMA_X509_PATH);
 102        ima_policy_flag |= unset_flags;
 103}
 104#endif
 105
 106int __init ima_init(void)
 107{
 108        u8 pcr_i[TPM_DIGEST_SIZE];
 109        int rc;
 110
 111        ima_used_chip = 0;
 112        rc = tpm_pcr_read(TPM_ANY_NUM, 0, pcr_i);
 113        if (rc == 0)
 114                ima_used_chip = 1;
 115
 116        if (!ima_used_chip)
 117                pr_info("No TPM chip found, activating TPM-bypass!\n");
 118
 119        rc = integrity_init_keyring(INTEGRITY_KEYRING_IMA);
 120        if (rc)
 121                return rc;
 122
 123        rc = ima_init_crypto();
 124        if (rc)
 125                return rc;
 126        rc = ima_init_template();
 127        if (rc != 0)
 128                return rc;
 129
 130        rc = ima_add_boot_aggregate();  /* boot aggregate must be first entry */
 131        if (rc != 0)
 132                return rc;
 133
 134        ima_init_policy();
 135
 136        return ima_fs_init();
 137}
 138