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Thomas Gleixnerb886d83c2019-06-01 10:08:55 +02001// SPDX-License-Identifier: GPL-2.0-only
Mimi Zohar3323eec2009-02-04 09:06:58 -05002/*
3 * Copyright (C) 2005,2006,2007,2008 IBM Corporation
4 *
5 * Authors:
6 * Serge Hallyn <serue@us.ibm.com>
7 * Reiner Sailer <sailer@watson.ibm.com>
8 * Mimi Zohar <zohar@us.ibm.com>
9 *
Mimi Zohar3323eec2009-02-04 09:06:58 -050010 * File: ima_queue.c
11 * Implements queues that store template measurements and
12 * maintains aggregate over the stored measurements
13 * in the pre-configured TPM PCR (if available).
14 * The measurement list is append-only. No entry is
15 * ever removed or changed during the boot-cycle.
16 */
Joe Perches20ee4512014-02-24 13:59:56 -080017
18#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
19
Mimi Zohar3323eec2009-02-04 09:06:58 -050020#include <linux/rculist.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090021#include <linux/slab.h>
Mimi Zohar3323eec2009-02-04 09:06:58 -050022#include "ima.h"
23
Roberto Sassu7b7e5912011-12-19 15:57:28 +010024#define AUDIT_CAUSE_LEN_MAX 32
25
Roberto Sassu0b6cf6b2019-02-06 17:24:52 +010026/* pre-allocated array of tpm_digest structures to extend a PCR */
27static struct tpm_digest *digests;
28
Mimi Zohar3323eec2009-02-04 09:06:58 -050029LIST_HEAD(ima_measurements); /* list of all measurements */
Mimi Zohard1588472016-12-19 16:22:42 -080030#ifdef CONFIG_IMA_KEXEC
31static unsigned long binary_runtime_size;
32#else
33static unsigned long binary_runtime_size = ULONG_MAX;
34#endif
Mimi Zohar3323eec2009-02-04 09:06:58 -050035
36/* key: inode (before secure-hashing a file) */
37struct ima_h_table ima_htable = {
38 .len = ATOMIC_LONG_INIT(0),
39 .violations = ATOMIC_LONG_INIT(0),
40 .queue[0 ... IMA_MEASURE_HTABLE_SIZE - 1] = HLIST_HEAD_INIT
41};
42
43/* mutex protects atomicity of extending measurement list
44 * and extending the TPM PCR aggregate. Since tpm_extend can take
45 * long (and the tpm driver uses a mutex), we can't use the spinlock.
46 */
47static DEFINE_MUTEX(ima_extend_list_mutex);
48
49/* lookup up the digest value in the hash table, and return the entry */
Eric Richter67696f62016-06-01 13:14:05 -050050static struct ima_queue_entry *ima_lookup_digest_entry(u8 *digest_value,
51 int pcr)
Mimi Zohar3323eec2009-02-04 09:06:58 -050052{
53 struct ima_queue_entry *qe, *ret = NULL;
54 unsigned int key;
Mimi Zohar3323eec2009-02-04 09:06:58 -050055 int rc;
56
57 key = ima_hash_key(digest_value);
58 rcu_read_lock();
Sasha Levinb67bfe02013-02-27 17:06:00 -080059 hlist_for_each_entry_rcu(qe, &ima_htable.queue[key], hnext) {
Mimi Zohar140d8022013-03-11 20:29:47 -040060 rc = memcmp(qe->entry->digest, digest_value, TPM_DIGEST_SIZE);
Eric Richter67696f62016-06-01 13:14:05 -050061 if ((rc == 0) && (qe->entry->pcr == pcr)) {
Mimi Zohar3323eec2009-02-04 09:06:58 -050062 ret = qe;
63 break;
64 }
65 }
66 rcu_read_unlock();
67 return ret;
68}
69
Mimi Zohard1588472016-12-19 16:22:42 -080070/*
71 * Calculate the memory required for serializing a single
72 * binary_runtime_measurement list entry, which contains a
73 * couple of variable length fields (e.g template name and data).
74 */
75static int get_binary_runtime_size(struct ima_template_entry *entry)
76{
77 int size = 0;
78
79 size += sizeof(u32); /* pcr */
80 size += sizeof(entry->digest);
81 size += sizeof(int); /* template name size field */
Roberto Sassue4586c792017-05-16 14:53:47 +020082 size += strlen(entry->template_desc->name);
Mimi Zohard1588472016-12-19 16:22:42 -080083 size += sizeof(entry->template_data_len);
84 size += entry->template_data_len;
85 return size;
86}
87
Mimi Zohar3323eec2009-02-04 09:06:58 -050088/* ima_add_template_entry helper function:
Mimi Zohardcfc5692016-12-19 16:22:38 -080089 * - Add template entry to the measurement list and hash table, for
90 * all entries except those carried across kexec.
Mimi Zohar3323eec2009-02-04 09:06:58 -050091 *
92 * (Called with ima_extend_list_mutex held.)
93 */
Mimi Zohardcfc5692016-12-19 16:22:38 -080094static int ima_add_digest_entry(struct ima_template_entry *entry,
95 bool update_htable)
Mimi Zohar3323eec2009-02-04 09:06:58 -050096{
97 struct ima_queue_entry *qe;
98 unsigned int key;
99
100 qe = kmalloc(sizeof(*qe), GFP_KERNEL);
101 if (qe == NULL) {
Joe Perches20ee4512014-02-24 13:59:56 -0800102 pr_err("OUT OF MEMORY ERROR creating queue entry\n");
Mimi Zohar3323eec2009-02-04 09:06:58 -0500103 return -ENOMEM;
104 }
105 qe->entry = entry;
106
107 INIT_LIST_HEAD(&qe->later);
108 list_add_tail_rcu(&qe->later, &ima_measurements);
109
110 atomic_long_inc(&ima_htable.len);
Mimi Zohardcfc5692016-12-19 16:22:38 -0800111 if (update_htable) {
112 key = ima_hash_key(entry->digest);
113 hlist_add_head_rcu(&qe->hnext, &ima_htable.queue[key]);
114 }
Mimi Zohard1588472016-12-19 16:22:42 -0800115
116 if (binary_runtime_size != ULONG_MAX) {
117 int size;
118
119 size = get_binary_runtime_size(entry);
120 binary_runtime_size = (binary_runtime_size < ULONG_MAX - size) ?
121 binary_runtime_size + size : ULONG_MAX;
122 }
Mimi Zohar3323eec2009-02-04 09:06:58 -0500123 return 0;
124}
125
Mimi Zohard1588472016-12-19 16:22:42 -0800126/*
127 * Return the amount of memory required for serializing the
128 * entire binary_runtime_measurement list, including the ima_kexec_hdr
129 * structure.
130 */
131unsigned long ima_get_binary_runtime_size(void)
132{
133 if (binary_runtime_size >= (ULONG_MAX - sizeof(struct ima_kexec_hdr)))
134 return ULONG_MAX;
135 else
136 return binary_runtime_size + sizeof(struct ima_kexec_hdr);
137};
138
Eric Richter544e1ce2016-06-01 13:14:07 -0500139static int ima_pcr_extend(const u8 *hash, int pcr)
Mimi Zohar3323eec2009-02-04 09:06:58 -0500140{
141 int result = 0;
Roberto Sassu0b6cf6b2019-02-06 17:24:52 +0100142 int i;
Mimi Zohar3323eec2009-02-04 09:06:58 -0500143
Stefan Bergerec403d8e2018-06-26 15:09:33 -0400144 if (!ima_tpm_chip)
Mimi Zohar3323eec2009-02-04 09:06:58 -0500145 return result;
146
Roberto Sassu0b6cf6b2019-02-06 17:24:52 +0100147 for (i = 0; i < ima_tpm_chip->nr_allocated_banks; i++)
148 memcpy(digests[i].digest, hash, TPM_DIGEST_SIZE);
149
150 result = tpm_pcr_extend(ima_tpm_chip, pcr, digests);
Mimi Zohar3323eec2009-02-04 09:06:58 -0500151 if (result != 0)
Joe Perches20ee4512014-02-24 13:59:56 -0800152 pr_err("Error Communicating to TPM chip, result: %d\n", result);
Mimi Zohar3323eec2009-02-04 09:06:58 -0500153 return result;
154}
155
Mimi Zohard1588472016-12-19 16:22:42 -0800156/*
157 * Add template entry to the measurement list and hash table, and
158 * extend the pcr.
159 *
160 * On systems which support carrying the IMA measurement list across
161 * kexec, maintain the total memory size required for serializing the
162 * binary_runtime_measurements.
Mimi Zohar3323eec2009-02-04 09:06:58 -0500163 */
164int ima_add_template_entry(struct ima_template_entry *entry, int violation,
Roberto Sassu9803d412013-06-07 12:16:27 +0200165 const char *op, struct inode *inode,
166 const unsigned char *filename)
Mimi Zohar3323eec2009-02-04 09:06:58 -0500167{
Mimi Zohar140d8022013-03-11 20:29:47 -0400168 u8 digest[TPM_DIGEST_SIZE];
Mimi Zohar3323eec2009-02-04 09:06:58 -0500169 const char *audit_cause = "hash_added";
Roberto Sassu7b7e5912011-12-19 15:57:28 +0100170 char tpm_audit_cause[AUDIT_CAUSE_LEN_MAX];
Mimi Zohar3323eec2009-02-04 09:06:58 -0500171 int audit_info = 1;
Roberto Sassu7b7e5912011-12-19 15:57:28 +0100172 int result = 0, tpmresult = 0;
Mimi Zohar3323eec2009-02-04 09:06:58 -0500173
174 mutex_lock(&ima_extend_list_mutex);
175 if (!violation) {
Dmitry Kasatkin2bb930a2014-03-04 18:04:20 +0200176 memcpy(digest, entry->digest, sizeof(digest));
Eric Richter67696f62016-06-01 13:14:05 -0500177 if (ima_lookup_digest_entry(digest, entry->pcr)) {
Mimi Zohar3323eec2009-02-04 09:06:58 -0500178 audit_cause = "hash_exists";
Roberto Sassu45fae742011-12-19 15:57:27 +0100179 result = -EEXIST;
Mimi Zohar3323eec2009-02-04 09:06:58 -0500180 goto out;
181 }
182 }
183
Mimi Zohardcfc5692016-12-19 16:22:38 -0800184 result = ima_add_digest_entry(entry, 1);
Mimi Zohar3323eec2009-02-04 09:06:58 -0500185 if (result < 0) {
186 audit_cause = "ENOMEM";
187 audit_info = 0;
188 goto out;
189 }
190
191 if (violation) /* invalidate pcr */
Dmitry Kasatkin2bb930a2014-03-04 18:04:20 +0200192 memset(digest, 0xff, sizeof(digest));
Mimi Zohar3323eec2009-02-04 09:06:58 -0500193
Eric Richter544e1ce2016-06-01 13:14:07 -0500194 tpmresult = ima_pcr_extend(digest, entry->pcr);
Roberto Sassu7b7e5912011-12-19 15:57:28 +0100195 if (tpmresult != 0) {
196 snprintf(tpm_audit_cause, AUDIT_CAUSE_LEN_MAX, "TPM_error(%d)",
197 tpmresult);
198 audit_cause = tpm_audit_cause;
Mimi Zohar3323eec2009-02-04 09:06:58 -0500199 audit_info = 0;
200 }
201out:
202 mutex_unlock(&ima_extend_list_mutex);
Roberto Sassu9803d412013-06-07 12:16:27 +0200203 integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, filename,
Mimi Zohar3323eec2009-02-04 09:06:58 -0500204 op, audit_cause, result, audit_info);
205 return result;
206}
Mimi Zohar94c3aac2016-12-19 16:22:35 -0800207
208int ima_restore_measurement_entry(struct ima_template_entry *entry)
209{
210 int result = 0;
211
212 mutex_lock(&ima_extend_list_mutex);
Mimi Zohardcfc5692016-12-19 16:22:38 -0800213 result = ima_add_digest_entry(entry, 0);
Mimi Zohar94c3aac2016-12-19 16:22:35 -0800214 mutex_unlock(&ima_extend_list_mutex);
215 return result;
216}
Roberto Sassu0b6cf6b2019-02-06 17:24:52 +0100217
218int __init ima_init_digests(void)
219{
220 int i;
221
222 if (!ima_tpm_chip)
223 return 0;
224
225 digests = kcalloc(ima_tpm_chip->nr_allocated_banks, sizeof(*digests),
226 GFP_NOFS);
227 if (!digests)
228 return -ENOMEM;
229
230 for (i = 0; i < ima_tpm_chip->nr_allocated_banks; i++)
231 digests[i].alg_id = ima_tpm_chip->allocated_banks[i].alg_id;
232
233 return 0;
234}