Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
[cris-mirror.git] / security / integrity / ima / ima_queue.c
blob418f35e38015a7cc337dbb6a7c9423c4b7ebaf8b
1 /*
2 * Copyright (C) 2005,2006,2007,2008 IBM Corporation
4 * Authors:
5 * Serge Hallyn <serue@us.ibm.com>
6 * Reiner Sailer <sailer@watson.ibm.com>
7 * Mimi Zohar <zohar@us.ibm.com>
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.
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.
22 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
24 #include <linux/module.h>
25 #include <linux/rculist.h>
26 #include <linux/slab.h>
27 #include "ima.h"
29 #define AUDIT_CAUSE_LEN_MAX 32
31 LIST_HEAD(ima_measurements); /* list of all measurements */
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
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
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.
49 static DEFINE_MUTEX(ima_extend_list_mutex);
51 /* lookup up the digest value in the hash table, and return the entry */
52 static struct ima_queue_entry *ima_lookup_digest_entry(u8 *digest_value,
53 int pcr)
55 struct ima_queue_entry *qe, *ret = NULL;
56 unsigned int key;
57 int rc;
59 key = ima_hash_key(digest_value);
60 rcu_read_lock();
61 hlist_for_each_entry_rcu(qe, &ima_htable.queue[key], hnext) {
62 rc = memcmp(qe->entry->digest, digest_value, TPM_DIGEST_SIZE);
63 if ((rc == 0) && (qe->entry->pcr == pcr)) {
64 ret = qe;
65 break;
68 rcu_read_unlock();
69 return ret;
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).
77 static int get_binary_runtime_size(struct ima_template_entry *entry)
79 int size = 0;
81 size += sizeof(u32); /* pcr */
82 size += sizeof(entry->digest);
83 size += sizeof(int); /* template name size field */
84 size += strlen(entry->template_desc->name);
85 size += sizeof(entry->template_data_len);
86 size += entry->template_data_len;
87 return size;
90 /* ima_add_template_entry helper function:
91 * - Add template entry to the measurement list and hash table, for
92 * all entries except those carried across kexec.
94 * (Called with ima_extend_list_mutex held.)
96 static int ima_add_digest_entry(struct ima_template_entry *entry,
97 bool update_htable)
99 struct ima_queue_entry *qe;
100 unsigned int key;
102 qe = kmalloc(sizeof(*qe), GFP_KERNEL);
103 if (qe == NULL) {
104 pr_err("OUT OF MEMORY ERROR creating queue entry\n");
105 return -ENOMEM;
107 qe->entry = entry;
109 INIT_LIST_HEAD(&qe->later);
110 list_add_tail_rcu(&qe->later, &ima_measurements);
112 atomic_long_inc(&ima_htable.len);
113 if (update_htable) {
114 key = ima_hash_key(entry->digest);
115 hlist_add_head_rcu(&qe->hnext, &ima_htable.queue[key]);
118 if (binary_runtime_size != ULONG_MAX) {
119 int size;
121 size = get_binary_runtime_size(entry);
122 binary_runtime_size = (binary_runtime_size < ULONG_MAX - size) ?
123 binary_runtime_size + size : ULONG_MAX;
125 return 0;
129 * Return the amount of memory required for serializing the
130 * entire binary_runtime_measurement list, including the ima_kexec_hdr
131 * structure.
133 unsigned long ima_get_binary_runtime_size(void)
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);
141 static int ima_pcr_extend(const u8 *hash, int pcr)
143 int result = 0;
145 if (!ima_used_chip)
146 return result;
148 result = tpm_pcr_extend(NULL, pcr, hash);
149 if (result != 0)
150 pr_err("Error Communicating to TPM chip, result: %d\n", result);
151 return result;
155 * Add template entry to the measurement list and hash table, and
156 * extend the pcr.
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.
162 int ima_add_template_entry(struct ima_template_entry *entry, int violation,
163 const char *op, struct inode *inode,
164 const unsigned char *filename)
166 u8 digest[TPM_DIGEST_SIZE];
167 const char *audit_cause = "hash_added";
168 char tpm_audit_cause[AUDIT_CAUSE_LEN_MAX];
169 int audit_info = 1;
170 int result = 0, tpmresult = 0;
172 mutex_lock(&ima_extend_list_mutex);
173 if (!violation) {
174 memcpy(digest, entry->digest, sizeof(digest));
175 if (ima_lookup_digest_entry(digest, entry->pcr)) {
176 audit_cause = "hash_exists";
177 result = -EEXIST;
178 goto out;
182 result = ima_add_digest_entry(entry, 1);
183 if (result < 0) {
184 audit_cause = "ENOMEM";
185 audit_info = 0;
186 goto out;
189 if (violation) /* invalidate pcr */
190 memset(digest, 0xff, sizeof(digest));
192 tpmresult = ima_pcr_extend(digest, entry->pcr);
193 if (tpmresult != 0) {
194 snprintf(tpm_audit_cause, AUDIT_CAUSE_LEN_MAX, "TPM_error(%d)",
195 tpmresult);
196 audit_cause = tpm_audit_cause;
197 audit_info = 0;
199 out:
200 mutex_unlock(&ima_extend_list_mutex);
201 integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, filename,
202 op, audit_cause, result, audit_info);
203 return result;
206 int ima_restore_measurement_entry(struct ima_template_entry *entry)
208 int result = 0;
210 mutex_lock(&ima_extend_list_mutex);
211 result = ima_add_digest_entry(entry, 0);
212 mutex_unlock(&ima_extend_list_mutex);
213 return result;