Mimi Zohar | 3323eec | 2009-02-04 09:06:58 -0500 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2005,2006,2007,2008 IBM Corporation |
| 3 | * |
| 4 | * Authors: |
| 5 | * Serge Hallyn <serue@us.ibm.com> |
| 6 | * Reiner Sailer <sailer@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_queue.c |
| 15 | * Implements queues that store template measurements and |
| 16 | * maintains aggregate over the stored measurements |
| 17 | * in the pre-configured TPM PCR (if available). |
| 18 | * The measurement list is append-only. No entry is |
| 19 | * ever removed or changed during the boot-cycle. |
| 20 | */ |
Joe Perches | 20ee451 | 2014-02-24 13:59:56 -0800 | [diff] [blame] | 21 | |
| 22 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 23 | |
Mimi Zohar | 3323eec | 2009-02-04 09:06:58 -0500 | [diff] [blame] | 24 | #include <linux/module.h> |
| 25 | #include <linux/rculist.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 26 | #include <linux/slab.h> |
Mimi Zohar | 3323eec | 2009-02-04 09:06:58 -0500 | [diff] [blame] | 27 | #include "ima.h" |
| 28 | |
Roberto Sassu | 7b7e591 | 2011-12-19 15:57:28 +0100 | [diff] [blame] | 29 | #define AUDIT_CAUSE_LEN_MAX 32 |
| 30 | |
Mimi Zohar | 3323eec | 2009-02-04 09:06:58 -0500 | [diff] [blame] | 31 | LIST_HEAD(ima_measurements); /* list of all measurements */ |
Mimi Zohar | d158847 | 2016-12-19 16:22:42 -0800 | [diff] [blame] | 32 | #ifdef CONFIG_IMA_KEXEC |
| 33 | static unsigned long binary_runtime_size; |
| 34 | #else |
| 35 | static unsigned long binary_runtime_size = ULONG_MAX; |
| 36 | #endif |
Mimi Zohar | 3323eec | 2009-02-04 09:06:58 -0500 | [diff] [blame] | 37 | |
| 38 | /* key: inode (before secure-hashing a file) */ |
| 39 | struct ima_h_table ima_htable = { |
| 40 | .len = ATOMIC_LONG_INIT(0), |
| 41 | .violations = ATOMIC_LONG_INIT(0), |
| 42 | .queue[0 ... IMA_MEASURE_HTABLE_SIZE - 1] = HLIST_HEAD_INIT |
| 43 | }; |
| 44 | |
| 45 | /* mutex protects atomicity of extending measurement list |
| 46 | * and extending the TPM PCR aggregate. Since tpm_extend can take |
| 47 | * long (and the tpm driver uses a mutex), we can't use the spinlock. |
| 48 | */ |
| 49 | static DEFINE_MUTEX(ima_extend_list_mutex); |
| 50 | |
| 51 | /* lookup up the digest value in the hash table, and return the entry */ |
Eric Richter | 67696f6 | 2016-06-01 13:14:05 -0500 | [diff] [blame] | 52 | static struct ima_queue_entry *ima_lookup_digest_entry(u8 *digest_value, |
| 53 | int pcr) |
Mimi Zohar | 3323eec | 2009-02-04 09:06:58 -0500 | [diff] [blame] | 54 | { |
| 55 | struct ima_queue_entry *qe, *ret = NULL; |
| 56 | unsigned int key; |
Mimi Zohar | 3323eec | 2009-02-04 09:06:58 -0500 | [diff] [blame] | 57 | int rc; |
| 58 | |
| 59 | key = ima_hash_key(digest_value); |
| 60 | rcu_read_lock(); |
Sasha Levin | b67bfe0 | 2013-02-27 17:06:00 -0800 | [diff] [blame] | 61 | hlist_for_each_entry_rcu(qe, &ima_htable.queue[key], hnext) { |
Mimi Zohar | 140d802 | 2013-03-11 20:29:47 -0400 | [diff] [blame] | 62 | rc = memcmp(qe->entry->digest, digest_value, TPM_DIGEST_SIZE); |
Eric Richter | 67696f6 | 2016-06-01 13:14:05 -0500 | [diff] [blame] | 63 | if ((rc == 0) && (qe->entry->pcr == pcr)) { |
Mimi Zohar | 3323eec | 2009-02-04 09:06:58 -0500 | [diff] [blame] | 64 | ret = qe; |
| 65 | break; |
| 66 | } |
| 67 | } |
| 68 | rcu_read_unlock(); |
| 69 | return ret; |
| 70 | } |
| 71 | |
Mimi Zohar | d158847 | 2016-12-19 16:22:42 -0800 | [diff] [blame] | 72 | /* |
| 73 | * Calculate the memory required for serializing a single |
| 74 | * binary_runtime_measurement list entry, which contains a |
| 75 | * couple of variable length fields (e.g template name and data). |
| 76 | */ |
| 77 | static int get_binary_runtime_size(struct ima_template_entry *entry) |
| 78 | { |
| 79 | int size = 0; |
| 80 | |
| 81 | size += sizeof(u32); /* pcr */ |
| 82 | size += sizeof(entry->digest); |
| 83 | size += sizeof(int); /* template name size field */ |
Roberto Sassu | e4586c79 | 2017-05-16 14:53:47 +0200 | [diff] [blame] | 84 | size += strlen(entry->template_desc->name); |
Mimi Zohar | d158847 | 2016-12-19 16:22:42 -0800 | [diff] [blame] | 85 | size += sizeof(entry->template_data_len); |
| 86 | size += entry->template_data_len; |
| 87 | return size; |
| 88 | } |
| 89 | |
Mimi Zohar | 3323eec | 2009-02-04 09:06:58 -0500 | [diff] [blame] | 90 | /* ima_add_template_entry helper function: |
Mimi Zohar | dcfc569 | 2016-12-19 16:22:38 -0800 | [diff] [blame] | 91 | * - Add template entry to the measurement list and hash table, for |
| 92 | * all entries except those carried across kexec. |
Mimi Zohar | 3323eec | 2009-02-04 09:06:58 -0500 | [diff] [blame] | 93 | * |
| 94 | * (Called with ima_extend_list_mutex held.) |
| 95 | */ |
Mimi Zohar | dcfc569 | 2016-12-19 16:22:38 -0800 | [diff] [blame] | 96 | static int ima_add_digest_entry(struct ima_template_entry *entry, |
| 97 | bool update_htable) |
Mimi Zohar | 3323eec | 2009-02-04 09:06:58 -0500 | [diff] [blame] | 98 | { |
| 99 | struct ima_queue_entry *qe; |
| 100 | unsigned int key; |
| 101 | |
| 102 | qe = kmalloc(sizeof(*qe), GFP_KERNEL); |
| 103 | if (qe == NULL) { |
Joe Perches | 20ee451 | 2014-02-24 13:59:56 -0800 | [diff] [blame] | 104 | pr_err("OUT OF MEMORY ERROR creating queue entry\n"); |
Mimi Zohar | 3323eec | 2009-02-04 09:06:58 -0500 | [diff] [blame] | 105 | return -ENOMEM; |
| 106 | } |
| 107 | qe->entry = entry; |
| 108 | |
| 109 | INIT_LIST_HEAD(&qe->later); |
| 110 | list_add_tail_rcu(&qe->later, &ima_measurements); |
| 111 | |
| 112 | atomic_long_inc(&ima_htable.len); |
Mimi Zohar | dcfc569 | 2016-12-19 16:22:38 -0800 | [diff] [blame] | 113 | if (update_htable) { |
| 114 | key = ima_hash_key(entry->digest); |
| 115 | hlist_add_head_rcu(&qe->hnext, &ima_htable.queue[key]); |
| 116 | } |
Mimi Zohar | d158847 | 2016-12-19 16:22:42 -0800 | [diff] [blame] | 117 | |
| 118 | if (binary_runtime_size != ULONG_MAX) { |
| 119 | int size; |
| 120 | |
| 121 | size = get_binary_runtime_size(entry); |
| 122 | binary_runtime_size = (binary_runtime_size < ULONG_MAX - size) ? |
| 123 | binary_runtime_size + size : ULONG_MAX; |
| 124 | } |
Mimi Zohar | 3323eec | 2009-02-04 09:06:58 -0500 | [diff] [blame] | 125 | return 0; |
| 126 | } |
| 127 | |
Mimi Zohar | d158847 | 2016-12-19 16:22:42 -0800 | [diff] [blame] | 128 | /* |
| 129 | * Return the amount of memory required for serializing the |
| 130 | * entire binary_runtime_measurement list, including the ima_kexec_hdr |
| 131 | * structure. |
| 132 | */ |
| 133 | unsigned long ima_get_binary_runtime_size(void) |
| 134 | { |
| 135 | if (binary_runtime_size >= (ULONG_MAX - sizeof(struct ima_kexec_hdr))) |
| 136 | return ULONG_MAX; |
| 137 | else |
| 138 | return binary_runtime_size + sizeof(struct ima_kexec_hdr); |
| 139 | }; |
| 140 | |
Eric Richter | 544e1ce | 2016-06-01 13:14:07 -0500 | [diff] [blame] | 141 | static int ima_pcr_extend(const u8 *hash, int pcr) |
Mimi Zohar | 3323eec | 2009-02-04 09:06:58 -0500 | [diff] [blame] | 142 | { |
| 143 | int result = 0; |
| 144 | |
| 145 | if (!ima_used_chip) |
| 146 | return result; |
| 147 | |
Jarkko Sakkinen | aad887f | 2017-11-05 13:16:26 +0200 | [diff] [blame] | 148 | result = tpm_pcr_extend(NULL, pcr, hash); |
Mimi Zohar | 3323eec | 2009-02-04 09:06:58 -0500 | [diff] [blame] | 149 | if (result != 0) |
Joe Perches | 20ee451 | 2014-02-24 13:59:56 -0800 | [diff] [blame] | 150 | pr_err("Error Communicating to TPM chip, result: %d\n", result); |
Mimi Zohar | 3323eec | 2009-02-04 09:06:58 -0500 | [diff] [blame] | 151 | return result; |
| 152 | } |
| 153 | |
Mimi Zohar | d158847 | 2016-12-19 16:22:42 -0800 | [diff] [blame] | 154 | /* |
| 155 | * Add template entry to the measurement list and hash table, and |
| 156 | * extend the pcr. |
| 157 | * |
| 158 | * On systems which support carrying the IMA measurement list across |
| 159 | * kexec, maintain the total memory size required for serializing the |
| 160 | * binary_runtime_measurements. |
Mimi Zohar | 3323eec | 2009-02-04 09:06:58 -0500 | [diff] [blame] | 161 | */ |
| 162 | int ima_add_template_entry(struct ima_template_entry *entry, int violation, |
Roberto Sassu | 9803d41 | 2013-06-07 12:16:27 +0200 | [diff] [blame] | 163 | const char *op, struct inode *inode, |
| 164 | const unsigned char *filename) |
Mimi Zohar | 3323eec | 2009-02-04 09:06:58 -0500 | [diff] [blame] | 165 | { |
Mimi Zohar | 140d802 | 2013-03-11 20:29:47 -0400 | [diff] [blame] | 166 | u8 digest[TPM_DIGEST_SIZE]; |
Mimi Zohar | 3323eec | 2009-02-04 09:06:58 -0500 | [diff] [blame] | 167 | const char *audit_cause = "hash_added"; |
Roberto Sassu | 7b7e591 | 2011-12-19 15:57:28 +0100 | [diff] [blame] | 168 | char tpm_audit_cause[AUDIT_CAUSE_LEN_MAX]; |
Mimi Zohar | 3323eec | 2009-02-04 09:06:58 -0500 | [diff] [blame] | 169 | int audit_info = 1; |
Roberto Sassu | 7b7e591 | 2011-12-19 15:57:28 +0100 | [diff] [blame] | 170 | int result = 0, tpmresult = 0; |
Mimi Zohar | 3323eec | 2009-02-04 09:06:58 -0500 | [diff] [blame] | 171 | |
| 172 | mutex_lock(&ima_extend_list_mutex); |
| 173 | if (!violation) { |
Dmitry Kasatkin | 2bb930a | 2014-03-04 18:04:20 +0200 | [diff] [blame] | 174 | memcpy(digest, entry->digest, sizeof(digest)); |
Eric Richter | 67696f6 | 2016-06-01 13:14:05 -0500 | [diff] [blame] | 175 | if (ima_lookup_digest_entry(digest, entry->pcr)) { |
Mimi Zohar | 3323eec | 2009-02-04 09:06:58 -0500 | [diff] [blame] | 176 | audit_cause = "hash_exists"; |
Roberto Sassu | 45fae74 | 2011-12-19 15:57:27 +0100 | [diff] [blame] | 177 | result = -EEXIST; |
Mimi Zohar | 3323eec | 2009-02-04 09:06:58 -0500 | [diff] [blame] | 178 | goto out; |
| 179 | } |
| 180 | } |
| 181 | |
Mimi Zohar | dcfc569 | 2016-12-19 16:22:38 -0800 | [diff] [blame] | 182 | result = ima_add_digest_entry(entry, 1); |
Mimi Zohar | 3323eec | 2009-02-04 09:06:58 -0500 | [diff] [blame] | 183 | if (result < 0) { |
| 184 | audit_cause = "ENOMEM"; |
| 185 | audit_info = 0; |
| 186 | goto out; |
| 187 | } |
| 188 | |
| 189 | if (violation) /* invalidate pcr */ |
Dmitry Kasatkin | 2bb930a | 2014-03-04 18:04:20 +0200 | [diff] [blame] | 190 | memset(digest, 0xff, sizeof(digest)); |
Mimi Zohar | 3323eec | 2009-02-04 09:06:58 -0500 | [diff] [blame] | 191 | |
Eric Richter | 544e1ce | 2016-06-01 13:14:07 -0500 | [diff] [blame] | 192 | tpmresult = ima_pcr_extend(digest, entry->pcr); |
Roberto Sassu | 7b7e591 | 2011-12-19 15:57:28 +0100 | [diff] [blame] | 193 | if (tpmresult != 0) { |
| 194 | snprintf(tpm_audit_cause, AUDIT_CAUSE_LEN_MAX, "TPM_error(%d)", |
| 195 | tpmresult); |
| 196 | audit_cause = tpm_audit_cause; |
Mimi Zohar | 3323eec | 2009-02-04 09:06:58 -0500 | [diff] [blame] | 197 | audit_info = 0; |
| 198 | } |
| 199 | out: |
| 200 | mutex_unlock(&ima_extend_list_mutex); |
Roberto Sassu | 9803d41 | 2013-06-07 12:16:27 +0200 | [diff] [blame] | 201 | integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, filename, |
Mimi Zohar | 3323eec | 2009-02-04 09:06:58 -0500 | [diff] [blame] | 202 | op, audit_cause, result, audit_info); |
| 203 | return result; |
| 204 | } |
Mimi Zohar | 94c3aac | 2016-12-19 16:22:35 -0800 | [diff] [blame] | 205 | |
| 206 | int ima_restore_measurement_entry(struct ima_template_entry *entry) |
| 207 | { |
| 208 | int result = 0; |
| 209 | |
| 210 | mutex_lock(&ima_extend_list_mutex); |
Mimi Zohar | dcfc569 | 2016-12-19 16:22:38 -0800 | [diff] [blame] | 211 | result = ima_add_digest_entry(entry, 0); |
Mimi Zohar | 94c3aac | 2016-12-19 16:22:35 -0800 | [diff] [blame] | 212 | mutex_unlock(&ima_extend_list_mutex); |
| 213 | return result; |
| 214 | } |