Mimi Zohar | 3323eec9 | 2009-02-04 09:06:58 -0500 | [diff] [blame^] | 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/err.h> |
| 20 | #include "ima.h" |
| 21 | |
| 22 | /* name for boot aggregate entry */ |
| 23 | static char *boot_aggregate_name = "boot_aggregate"; |
| 24 | int ima_used_chip; |
| 25 | |
| 26 | /* Add the boot aggregate to the IMA measurement list and extend |
| 27 | * the PCR register. |
| 28 | * |
| 29 | * Calculate the boot aggregate, a SHA1 over tpm registers 0-7, |
| 30 | * assuming a TPM chip exists, and zeroes if the TPM chip does not |
| 31 | * exist. Add the boot aggregate measurement to the measurement |
| 32 | * list and extend the PCR register. |
| 33 | * |
| 34 | * If a tpm chip does not exist, indicate the core root of trust is |
| 35 | * not hardware based by invalidating the aggregate PCR value. |
| 36 | * (The aggregate PCR value is invalidated by adding one value to |
| 37 | * the measurement list and extending the aggregate PCR value with |
| 38 | * a different value.) Violations add a zero entry to the measurement |
| 39 | * list and extend the aggregate PCR value with ff...ff's. |
| 40 | */ |
| 41 | static void ima_add_boot_aggregate(void) |
| 42 | { |
| 43 | struct ima_template_entry *entry; |
| 44 | const char *op = "add_boot_aggregate"; |
| 45 | const char *audit_cause = "ENOMEM"; |
| 46 | int result = -ENOMEM; |
| 47 | int violation = 1; |
| 48 | |
| 49 | entry = kmalloc(sizeof(*entry), GFP_KERNEL); |
| 50 | if (!entry) |
| 51 | goto err_out; |
| 52 | |
| 53 | memset(&entry->template, 0, sizeof(entry->template)); |
| 54 | strncpy(entry->template.file_name, boot_aggregate_name, |
| 55 | IMA_EVENT_NAME_LEN_MAX); |
| 56 | if (ima_used_chip) { |
| 57 | violation = 0; |
| 58 | result = ima_calc_boot_aggregate(entry->template.digest); |
| 59 | if (result < 0) { |
| 60 | audit_cause = "hashing_error"; |
| 61 | kfree(entry); |
| 62 | goto err_out; |
| 63 | } |
| 64 | } |
| 65 | result = ima_store_template(entry, violation, NULL); |
| 66 | if (result < 0) |
| 67 | kfree(entry); |
| 68 | return; |
| 69 | err_out: |
| 70 | integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, boot_aggregate_name, op, |
| 71 | audit_cause, result, 0); |
| 72 | } |
| 73 | |
| 74 | int ima_init(void) |
| 75 | { |
| 76 | u8 pcr_i[IMA_DIGEST_SIZE]; |
| 77 | int rc; |
| 78 | |
| 79 | ima_used_chip = 0; |
| 80 | rc = tpm_pcr_read(TPM_ANY_NUM, 0, pcr_i); |
| 81 | if (rc == 0) |
| 82 | ima_used_chip = 1; |
| 83 | |
| 84 | if (!ima_used_chip) |
| 85 | pr_info("No TPM chip found, activating TPM-bypass!\n"); |
| 86 | |
| 87 | ima_add_boot_aggregate(); /* boot aggregate must be first entry */ |
| 88 | ima_init_policy(); |
| 89 | return 0; |
| 90 | } |