security/integrity/ima/ima_init.c

   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 #include <linux/init.h>
  15 #include <linux/scatterlist.h>
  16 #include <linux/slab.h>
  17 #include <linux/err.h>
  18 #include <linux/ima.h>
  19 #include <generated/utsrelease.h>
  20
  21 #include "ima.h"
  22
  23 /* name for boot aggregate entry */
  24 const char boot_aggregate_name[] = "boot_aggregate";
  25 struct 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 hash 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  */
  42 static 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 ima_iint_cache tmp_iint, *iint = &tmp_iint;
  48         struct ima_event_data event_data = { .iint = iint,
  49                                              .filename = boot_aggregate_name };
  50         struct ima_max_digest_data hash;
  51         struct ima_digest_data *hash_hdr = container_of(&hash.hdr,
  52                                                 struct ima_digest_data, hdr);
  53         int result = -ENOMEM;
  54         int violation = 0;
  55
  56         memset(iint, 0, sizeof(*iint));
  57         memset(&hash, 0, sizeof(hash));
  58         iint->ima_hash = hash_hdr;
  59         iint->ima_hash->algo = ima_hash_algo;
  60         iint->ima_hash->length = hash_digest_size[ima_hash_algo];
  61
  62         /*
  63          * With TPM 2.0 hash agility, TPM chips could support multiple TPM
  64          * PCR banks, allowing firmware to configure and enable different
  65          * banks.  The SHA1 bank is not necessarily enabled.
  66          *
  67          * Use the same hash algorithm for reading the TPM PCRs as for
  68          * calculating the boot aggregate digest.  Preference is given to
  69          * the configured IMA default hash algorithm.  Otherwise, use the
  70          * TCG required banks - SHA256 for TPM 2.0, SHA1 for TPM 1.2.
  71          * Ultimately select SHA1 also for TPM 2.0 if the SHA256 PCR bank
  72          * is not found.
  73          */
  74         if (ima_tpm_chip) {
  75                 result = ima_calc_boot_aggregate(hash_hdr);
  76                 if (result < 0) {
  77                         audit_cause = "hashing_error";
  78                         goto err_out;
  79                 }
  80         }
  81
  82         result = ima_alloc_init_template(&event_data, &entry, NULL);
  83         if (result < 0) {
  84                 audit_cause = "alloc_entry";
  85                 goto err_out;
  86         }
  87
  88         result = ima_store_template(entry, violation, NULL,
  89                                     boot_aggregate_name,
  90                                     CONFIG_IMA_MEASURE_PCR_IDX);
  91         if (result < 0) {
  92                 ima_free_template_entry(entry);
  93                 audit_cause = "store_entry";
  94                 goto err_out;
  95         }
  96         return 0;
  97 err_out:
  98         integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, boot_aggregate_name, op,
  99                             audit_cause, result, 0);
 100         return result;
 101 }
 102
 103 #ifdef CONFIG_IMA_LOAD_X509
 104 void __init ima_load_x509(void)
 105 {
 106         int unset_flags = ima_policy_flag & IMA_APPRAISE;
 107
 108         ima_policy_flag &= ~unset_flags;
 109         integrity_load_x509(INTEGRITY_KEYRING_IMA, CONFIG_IMA_X509_PATH);
 110
 111         /* load also EVM key to avoid appraisal */
 112         evm_load_x509();
 113
 114         ima_policy_flag |= unset_flags;
 115 }
 116 #endif
 117
 118 int __init ima_init(void)
 119 {
 120         int rc;
 121
 122         ima_tpm_chip = tpm_default_chip();
 123         if (!ima_tpm_chip)
 124                 pr_info("No TPM chip found, activating TPM-bypass!\n");
 125
 126         rc = integrity_init_keyring(INTEGRITY_KEYRING_IMA);
 127         if (rc)
 128                 return rc;
 129
 130         rc = ima_init_crypto();
 131         if (rc)
 132                 return rc;
 133         rc = ima_init_template();
 134         if (rc != 0)
 135                 return rc;
 136
 137         /* It can be called before ima_init_digests(), it does not use TPM. */
 138         ima_load_kexec_buffer();
 139
 140         rc = ima_init_digests();
 141         if (rc != 0)
 142                 return rc;
 143         rc = ima_add_boot_aggregate();  /* boot aggregate must be first entry */
 144         if (rc != 0)
 145                 return rc;
 146
 147         ima_init_policy();
 148
 149         rc = ima_fs_init();
 150         if (rc != 0)
 151                 return rc;
 152
 153         ima_init_key_queue();
 154
 155         ima_measure_critical_data("kernel_info", "kernel_version",
 156                                   UTS_RELEASE, strlen(UTS_RELEASE), false,
 157                                   NULL, 0);
 158
 159         return rc;
 160 }