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 #include <crypto/hash_info.h>
  25 #include "ima.h"
  26
  27 #ifdef CONFIG_IMA_X509_PATH
  28 #define IMA_X509_PATH   CONFIG_IMA_X509_PATH
  29 #else
  30 #define IMA_X509_PATH   "/etc/keys/x509_ima.der"
  31 #endif
  32
  33 /* name for boot aggregate entry */
  34 static const char *boot_aggregate_name = "boot_aggregate";
  35 int ima_used_chip;
  36
  37 /* Add the boot aggregate to the IMA measurement list and extend
  38  * the PCR register.
  39  *
  40  * Calculate the boot aggregate, a SHA1 over tpm registers 0-7,
  41  * assuming a TPM chip exists, and zeroes if the TPM chip does not
  42  * exist.  Add the boot aggregate measurement to the measurement
  43  * list and extend the PCR register.
  44  *
  45  * If a tpm chip does not exist, indicate the core root of trust is
  46  * not hardware based by invalidating the aggregate PCR value.
  47  * (The aggregate PCR value is invalidated by adding one value to
  48  * the measurement list and extending the aggregate PCR value with
  49  * a different value.) Violations add a zero entry to the measurement
  50  * list and extend the aggregate PCR value with ff...ff's.
  51  */
  52 static int __init ima_add_boot_aggregate(void)
  53 {
  54         static const char op[] = "add_boot_aggregate";
  55         const char *audit_cause = "ENOMEM";
  56         struct ima_template_entry *entry;
  57         struct integrity_iint_cache tmp_iint, *iint = &tmp_iint;
  58         int result = -ENOMEM;
  59         int violation = 0;
  60         struct {
  61                 struct ima_digest_data hdr;
  62                 char digest[TPM_DIGEST_SIZE];
  63         } hash;
  64
  65         memset(iint, 0, sizeof(*iint));
  66         memset(&hash, 0, sizeof(hash));
  67         iint->ima_hash = &hash.hdr;
  68         iint->ima_hash->algo = HASH_ALGO_SHA1;
  69         iint->ima_hash->length = SHA1_DIGEST_SIZE;
  70
  71         if (ima_used_chip) {
  72                 result = ima_calc_boot_aggregate(&hash.hdr);
  73                 if (result < 0) {
  74                         audit_cause = "hashing_error";
  75                         goto err_out;
  76                 }
  77         }
  78
  79         result = ima_alloc_init_template(iint, NULL, boot_aggregate_name,
  80                                          NULL, 0, &entry);
  81         if (result < 0) {
  82                 audit_cause = "alloc_entry";
  83                 goto err_out;
  84         }
  85
  86         result = ima_store_template(entry, violation, NULL,
  87                                     boot_aggregate_name);
  88         if (result < 0) {
  89                 ima_free_template_entry(entry);
  90                 audit_cause = "store_entry";
  91                 goto err_out;
  92         }
  93         return 0;
  94 err_out:
  95         integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, boot_aggregate_name, op,
  96                             audit_cause, result, 0);
  97         return result;
  98 }
  99
 100 #ifdef CONFIG_IMA_LOAD_X509
 101 void __init ima_load_x509(void)
 102 {
 103         int unset_flags = ima_policy_flag & IMA_APPRAISE;
 104
 105         ima_policy_flag &= ~unset_flags;
 106         integrity_load_x509(INTEGRITY_KEYRING_IMA, IMA_X509_PATH);
 107         ima_policy_flag |= unset_flags;
 108 }
 109 #endif
 110
 111 int __init ima_init(void)
 112 {
 113         u8 pcr_i[TPM_DIGEST_SIZE];
 114         int rc;
 115
 116         ima_used_chip = 0;
 117         rc = tpm_pcr_read(TPM_ANY_NUM, 0, pcr_i);
 118         if (rc == 0)
 119                 ima_used_chip = 1;
 120
 121         if (!ima_used_chip)
 122                 pr_info("No TPM chip found, activating TPM-bypass!\n");
 123
 124         rc = ima_init_keyring(INTEGRITY_KEYRING_IMA);
 125         if (rc)
 126                 return rc;
 127
 128         rc = ima_init_crypto();
 129         if (rc)
 130                 return rc;
 131         rc = ima_init_template();
 132         if (rc != 0)
 133                 return rc;
 134
 135         rc = ima_add_boot_aggregate();  /* boot aggregate must be first entry */
 136         if (rc != 0)
 137                 return rc;
 138
 139         ima_init_policy();
 140
 141         return ima_fs_init();
 142 }