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 const 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 90 return ima_fs_init(); 91 } 92 93 void __exit ima_cleanup(void) 94 { 95 ima_fs_cleanup(); 96 } 97