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 /* 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 int result = -ENOMEM; 53 int violation = 0; 54 struct { 55 struct ima_digest_data hdr; 56 char digest[TPM_DIGEST_SIZE]; 57 } hash; 58 59 memset(iint, 0, sizeof(*iint)); 60 memset(&hash, 0, sizeof(hash)); 61 iint->ima_hash = &hash.hdr; 62 iint->ima_hash->algo = HASH_ALGO_SHA1; 63 iint->ima_hash->length = SHA1_DIGEST_SIZE; 64 65 if (ima_used_chip) { 66 result = ima_calc_boot_aggregate(&hash.hdr); 67 if (result < 0) { 68 audit_cause = "hashing_error"; 69 goto err_out; 70 } 71 } 72 73 result = ima_alloc_init_template(iint, NULL, boot_aggregate_name, 74 NULL, 0, &entry); 75 if (result < 0) { 76 audit_cause = "alloc_entry"; 77 goto err_out; 78 } 79 80 result = ima_store_template(entry, violation, NULL, 81 boot_aggregate_name); 82 if (result < 0) { 83 ima_free_template_entry(entry); 84 audit_cause = "store_entry"; 85 goto err_out; 86 } 87 return 0; 88 err_out: 89 integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, boot_aggregate_name, op, 90 audit_cause, result, 0); 91 return result; 92 } 93 94 int __init ima_init(void) 95 { 96 u8 pcr_i[TPM_DIGEST_SIZE]; 97 int rc; 98 99 ima_used_chip = 0; 100 rc = tpm_pcr_read(TPM_ANY_NUM, 0, pcr_i); 101 if (rc == 0) 102 ima_used_chip = 1; 103 104 if (!ima_used_chip) 105 pr_info("No TPM chip found, activating TPM-bypass!\n"); 106 107 rc = ima_init_keyring(INTEGRITY_KEYRING_IMA); 108 if (rc) 109 return rc; 110 111 rc = ima_init_crypto(); 112 if (rc) 113 return rc; 114 rc = ima_init_template(); 115 if (rc != 0) 116 return rc; 117 118 rc = ima_add_boot_aggregate(); /* boot aggregate must be first entry */ 119 if (rc != 0) 120 return rc; 121 122 ima_init_policy(); 123 124 return ima_fs_init(); 125 } 126