1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2005,2006,2007,2008 IBM Corporation
6 * Serge Hallyn <serue@us.ibm.com>
7 * Reiner Sailer <sailer@watson.ibm.com>
8 * Mimi Zohar <zohar@us.ibm.com>
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.
18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20 #include <linux/rculist.h>
21 #include <linux/slab.h>
24 #define AUDIT_CAUSE_LEN_MAX 32
26 /* pre-allocated array of tpm_digest structures to extend a PCR */
27 static struct tpm_digest *digests;
29 LIST_HEAD(ima_measurements); /* list of all measurements */
30 #ifdef CONFIG_IMA_KEXEC
31 static unsigned long binary_runtime_size;
33 static unsigned long binary_runtime_size = ULONG_MAX;
36 /* key: inode (before secure-hashing a file) */
37 struct 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
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.
47 static DEFINE_MUTEX(ima_extend_list_mutex);
49 /* lookup up the digest value in the hash table, and return the entry */
50 static struct ima_queue_entry *ima_lookup_digest_entry(u8 *digest_value,
53 struct ima_queue_entry *qe, *ret = NULL;
57 key = ima_hash_key(digest_value);
59 hlist_for_each_entry_rcu(qe, &ima_htable.queue[key], hnext) {
60 rc = memcmp(qe->entry->digest, digest_value, TPM_DIGEST_SIZE);
61 if ((rc == 0) && (qe->entry->pcr == pcr)) {
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).
75 static int get_binary_runtime_size(struct ima_template_entry *entry)
79 size += sizeof(u32); /* pcr */
80 size += sizeof(entry->digest);
81 size += sizeof(int); /* template name size field */
82 size += strlen(entry->template_desc->name);
83 size += sizeof(entry->template_data_len);
84 size += entry->template_data_len;
88 /* ima_add_template_entry helper function:
89 * - Add template entry to the measurement list and hash table, for
90 * all entries except those carried across kexec.
92 * (Called with ima_extend_list_mutex held.)
94 static int ima_add_digest_entry(struct ima_template_entry *entry,
97 struct ima_queue_entry *qe;
100 qe = kmalloc(sizeof(*qe), GFP_KERNEL);
102 pr_err("OUT OF MEMORY ERROR creating queue entry\n");
107 INIT_LIST_HEAD(&qe->later);
108 list_add_tail_rcu(&qe->later, &ima_measurements);
110 atomic_long_inc(&ima_htable.len);
112 key = ima_hash_key(entry->digest);
113 hlist_add_head_rcu(&qe->hnext, &ima_htable.queue[key]);
116 if (binary_runtime_size != ULONG_MAX) {
119 size = get_binary_runtime_size(entry);
120 binary_runtime_size = (binary_runtime_size < ULONG_MAX - size) ?
121 binary_runtime_size + size : ULONG_MAX;
127 * Return the amount of memory required for serializing the
128 * entire binary_runtime_measurement list, including the ima_kexec_hdr
131 unsigned long ima_get_binary_runtime_size(void)
133 if (binary_runtime_size >= (ULONG_MAX - sizeof(struct ima_kexec_hdr)))
136 return binary_runtime_size + sizeof(struct ima_kexec_hdr);
139 static int ima_pcr_extend(const u8 *hash, int pcr)
147 for (i = 0; i < ima_tpm_chip->nr_allocated_banks; i++)
148 memcpy(digests[i].digest, hash, TPM_DIGEST_SIZE);
150 result = tpm_pcr_extend(ima_tpm_chip, pcr, digests);
152 pr_err("Error Communicating to TPM chip, result: %d\n", result);
157 * Add template entry to the measurement list and hash table, and
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.
164 int ima_add_template_entry(struct ima_template_entry *entry, int violation,
165 const char *op, struct inode *inode,
166 const unsigned char *filename)
168 u8 digest[TPM_DIGEST_SIZE];
169 const char *audit_cause = "hash_added";
170 char tpm_audit_cause[AUDIT_CAUSE_LEN_MAX];
172 int result = 0, tpmresult = 0;
174 mutex_lock(&ima_extend_list_mutex);
176 memcpy(digest, entry->digest, sizeof(digest));
177 if (ima_lookup_digest_entry(digest, entry->pcr)) {
178 audit_cause = "hash_exists";
184 result = ima_add_digest_entry(entry, 1);
186 audit_cause = "ENOMEM";
191 if (violation) /* invalidate pcr */
192 memset(digest, 0xff, sizeof(digest));
194 tpmresult = ima_pcr_extend(digest, entry->pcr);
195 if (tpmresult != 0) {
196 snprintf(tpm_audit_cause, AUDIT_CAUSE_LEN_MAX, "TPM_error(%d)",
198 audit_cause = tpm_audit_cause;
202 mutex_unlock(&ima_extend_list_mutex);
203 integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, filename,
204 op, audit_cause, result, audit_info);
208 int ima_restore_measurement_entry(struct ima_template_entry *entry)
212 mutex_lock(&ima_extend_list_mutex);
213 result = ima_add_digest_entry(entry, 0);
214 mutex_unlock(&ima_extend_list_mutex);
218 int __init ima_init_digests(void)
225 digests = kcalloc(ima_tpm_chip->nr_allocated_banks, sizeof(*digests),
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;