security/integrity/ima/ima_init.c

   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 */
  28 static const char *boot_aggregate_name = "boot_aggregate";
  29 int 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  */
  46 static 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                                     CONFIG_IMA_MEASURE_PCR_IDX);
  84         if (result < 0) {
  85                 ima_free_template_entry(entry);
  86                 audit_cause = "store_entry";
  87                 goto err_out;
  88         }
  89         return 0;
  90 err_out:
  91         integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, boot_aggregate_name, op,
  92                             audit_cause, result, 0);
  93         return result;
  94 }
  95
  96 #ifdef CONFIG_IMA_LOAD_X509
  97 void __init ima_load_x509(void)
  98 {
  99         int unset_flags = ima_policy_flag & IMA_APPRAISE;
 100
 101         ima_policy_flag &= ~unset_flags;
 102         integrity_load_x509(INTEGRITY_KEYRING_IMA, CONFIG_IMA_X509_PATH);
 103         ima_policy_flag |= unset_flags;
 104 }
 105 #endif
 106
 107 int __init ima_init(void)
 108 {
 109         u8 pcr_i[TPM_DIGEST_SIZE];
 110         int rc;
 111
 112         ima_used_chip = 0;
 113         rc = tpm_pcr_read(NULL, 0, pcr_i);
 114         if (rc == 0)
 115                 ima_used_chip = 1;
 116
 117         if (!ima_used_chip)
 118                 pr_info("No TPM chip found, activating TPM-bypass! (rc=%d)\n",
 119                         rc);
 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         ima_load_kexec_buffer();
 133
 134         rc = ima_add_boot_aggregate();  /* boot aggregate must be first entry */
 135         if (rc != 0)
 136                 return rc;
 137
 138         ima_init_policy();
 139
 140         return ima_fs_init();
 141 }