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 <crypto/hash_info.h> 22 #include "ima.h" 23 24 /* name for boot aggregate entry */ 25 static const char *boot_aggregate_name = "boot_aggregate"; 26 int ima_used_chip; 27 28 /* Add the boot aggregate to the IMA measurement list and extend 29 * the PCR register. 30 * 31 * Calculate the boot aggregate, a SHA1 over tpm registers 0-7, 32 * assuming a TPM chip exists, and zeroes if the TPM chip does not 33 * exist. Add the boot aggregate measurement to the measurement 34 * list and extend the PCR register. 35 * 36 * If a tpm chip does not exist, indicate the core root of trust is 37 * not hardware based by invalidating the aggregate PCR value. 38 * (The aggregate PCR value is invalidated by adding one value to 39 * the measurement list and extending the aggregate PCR value with 40 * a different value.) Violations add a zero entry to the measurement 41 * list and extend the aggregate PCR value with ff...ff's. 42 */ 43 static void __init ima_add_boot_aggregate(void) 44 { 45 struct ima_template_entry *entry; 46 struct integrity_iint_cache tmp_iint, *iint = &tmp_iint; 47 const char *op = "add_boot_aggregate"; 48 const char *audit_cause = "ENOMEM"; 49 int result = -ENOMEM; 50 int violation = 0; 51 struct { 52 struct ima_digest_data hdr; 53 char digest[TPM_DIGEST_SIZE]; 54 } hash; 55 56 memset(iint, 0, sizeof(*iint)); 57 memset(&hash, 0, sizeof(hash)); 58 iint->ima_hash = &hash.hdr; 59 iint->ima_hash->algo = HASH_ALGO_SHA1; 60 iint->ima_hash->length = SHA1_DIGEST_SIZE; 61 62 if (ima_used_chip) { 63 result = ima_calc_boot_aggregate(&hash.hdr); 64 if (result < 0) { 65 audit_cause = "hashing_error"; 66 kfree(entry); 67 goto err_out; 68 } 69 } 70 71 result = ima_alloc_init_template(iint, NULL, boot_aggregate_name, 72 &entry); 73 if (result < 0) 74 return; 75 76 result = ima_store_template(entry, violation, NULL, 77 boot_aggregate_name); 78 if (result < 0) 79 kfree(entry); 80 return; 81 err_out: 82 integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, boot_aggregate_name, op, 83 audit_cause, result, 0); 84 } 85 86 int __init ima_init(void) 87 { 88 u8 pcr_i[TPM_DIGEST_SIZE]; 89 int rc; 90 91 ima_used_chip = 0; 92 rc = tpm_pcr_read(TPM_ANY_NUM, 0, pcr_i); 93 if (rc == 0) 94 ima_used_chip = 1; 95 96 if (!ima_used_chip) 97 pr_info("IMA: No TPM chip found, activating TPM-bypass!\n"); 98 99 rc = ima_init_crypto(); 100 if (rc) 101 return rc; 102 rc = ima_init_template(); 103 if (rc != 0) 104 return rc; 105 106 ima_add_boot_aggregate(); /* boot aggregate must be first entry */ 107 ima_init_policy(); 108 109 return ima_fs_init(); 110 } 111