2 * Copyright (C) 2005,2006,2007,2008 IBM Corporation
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
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>
29 #define AUDIT_CAUSE_LEN_MAX 32
31 LIST_HEAD(ima_measurements); /* list of all measurements */
33 /* key: inode (before secure-hashing a file) */
34 struct ima_h_table ima_htable = {
35 .len = ATOMIC_LONG_INIT(0),
36 .violations = ATOMIC_LONG_INIT(0),
37 .queue[0 ... IMA_MEASURE_HTABLE_SIZE - 1] = HLIST_HEAD_INIT
40 /* mutex protects atomicity of extending measurement list
41 * and extending the TPM PCR aggregate. Since tpm_extend can take
42 * long (and the tpm driver uses a mutex), we can't use the spinlock.
44 static DEFINE_MUTEX(ima_extend_list_mutex);
46 /* lookup up the digest value in the hash table, and return the entry */
47 static struct ima_queue_entry *ima_lookup_digest_entry(u8 *digest_value,
50 struct ima_queue_entry *qe, *ret = NULL;
54 key = ima_hash_key(digest_value);
56 hlist_for_each_entry_rcu(qe, &ima_htable.queue[key], hnext) {
57 rc = memcmp(qe->entry->digest, digest_value, TPM_DIGEST_SIZE);
58 if ((rc == 0) && (qe->entry->pcr == pcr)) {
67 /* ima_add_template_entry helper function:
68 * - Add template entry to measurement list and hash table.
70 * (Called with ima_extend_list_mutex held.)
72 static int ima_add_digest_entry(struct ima_template_entry *entry)
74 struct ima_queue_entry *qe;
77 qe = kmalloc(sizeof(*qe), GFP_KERNEL);
79 pr_err("OUT OF MEMORY ERROR creating queue entry\n");
84 INIT_LIST_HEAD(&qe->later);
85 list_add_tail_rcu(&qe->later, &ima_measurements);
87 atomic_long_inc(&ima_htable.len);
88 key = ima_hash_key(entry->digest);
89 hlist_add_head_rcu(&qe->hnext, &ima_htable.queue[key]);
93 static int ima_pcr_extend(const u8 *hash, int pcr)
100 result = tpm_pcr_extend(TPM_ANY_NUM, pcr, hash);
102 pr_err("Error Communicating to TPM chip, result: %d\n", result);
106 /* Add template entry to the measurement list and hash table,
107 * and extend the pcr.
109 int ima_add_template_entry(struct ima_template_entry *entry, int violation,
110 const char *op, struct inode *inode,
111 const unsigned char *filename)
113 u8 digest[TPM_DIGEST_SIZE];
114 const char *audit_cause = "hash_added";
115 char tpm_audit_cause[AUDIT_CAUSE_LEN_MAX];
117 int result = 0, tpmresult = 0;
119 mutex_lock(&ima_extend_list_mutex);
121 memcpy(digest, entry->digest, sizeof(digest));
122 if (ima_lookup_digest_entry(digest, entry->pcr)) {
123 audit_cause = "hash_exists";
129 result = ima_add_digest_entry(entry);
131 audit_cause = "ENOMEM";
136 if (violation) /* invalidate pcr */
137 memset(digest, 0xff, sizeof(digest));
139 tpmresult = ima_pcr_extend(digest, entry->pcr);
140 if (tpmresult != 0) {
141 snprintf(tpm_audit_cause, AUDIT_CAUSE_LEN_MAX, "TPM_error(%d)",
143 audit_cause = tpm_audit_cause;
147 mutex_unlock(&ima_extend_list_mutex);
148 integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, filename,
149 op, audit_cause, result, audit_info);