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         if (result < 0) {
  84                 ima_free_template_entry(entry);
  85                 audit_cause = "store_entry";
  86                 goto err_out;
  87         }
  88         return 0;
  89 err_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
  96 void __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
 106 int __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 }