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#include <linux/module.h>
  18#include <linux/scatterlist.h>
  19#include <linux/slab.h>
  20#include <linux/err.h>
  21#include "ima.h"
  22
  23/* name for boot aggregate entry */
  24static const char *boot_aggregate_name = "boot_aggregate";
  25int ima_used_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 SHA1 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 */
  42static void __init ima_add_boot_aggregate(void)
  43{
  44        struct ima_template_entry *entry;
  45        const char *op = "add_boot_aggregate";
  46        const char *audit_cause = "ENOMEM";
  47        int result = -ENOMEM;
  48        int violation = 1;
  49
  50        entry = kmalloc(sizeof(*entry), GFP_KERNEL);
  51        if (!entry)
  52                goto err_out;
  53
  54        memset(&entry->template, 0, sizeof(entry->template));
  55        strncpy(entry->template.file_name, boot_aggregate_name,
  56                IMA_EVENT_NAME_LEN_MAX);
  57        if (ima_used_chip) {
  58                violation = 0;
  59                result = ima_calc_boot_aggregate(entry->template.digest);
  60                if (result < 0) {
  61                        audit_cause = "hashing_error";
  62                        kfree(entry);
  63                        goto err_out;
  64                }
  65        }
  66        result = ima_store_template(entry, violation, NULL);
  67        if (result < 0)
  68                kfree(entry);
  69        return;
  70err_out:
  71        integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, boot_aggregate_name, op,
  72                            audit_cause, result, 0);
  73}
  74
  75int __init ima_init(void)
  76{
  77        u8 pcr_i[IMA_DIGEST_SIZE];
  78        int rc;
  79
  80        ima_used_chip = 0;
  81        rc = tpm_pcr_read(NULL, 0, pcr_i);
  82        if (rc == 0)
  83                ima_used_chip = 1;
  84
  85        if (!ima_used_chip)
  86                pr_info("IMA: No TPM chip found, activating TPM-bypass! (rc=%d)\n",
  87                        rc);
  88
  89        rc = ima_init_crypto();
  90        if (rc)
  91                return rc;
  92        ima_add_boot_aggregate();       /* boot aggregate must be first entry */
  93        ima_init_policy();
  94
  95        return ima_fs_init();
  96}
  97