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)
49 struct ima_queue_entry *qe, *ret = NULL;
53 key = ima_hash_key(digest_value);
55 hlist_for_each_entry_rcu(qe, &ima_htable.queue[key], hnext) {
56 rc = memcmp(qe->entry->digest, digest_value, TPM_DIGEST_SIZE);
66 /* ima_add_template_entry helper function:
67 * - Add template entry to measurement list and hash table.
69 * (Called with ima_extend_list_mutex held.)
71 static int ima_add_digest_entry(struct ima_template_entry *entry)
73 struct ima_queue_entry *qe;
76 qe = kmalloc(sizeof(*qe), GFP_KERNEL);
78 pr_err("OUT OF MEMORY ERROR creating queue entry\n");
83 INIT_LIST_HEAD(&qe->later);
84 list_add_tail_rcu(&qe->later, &ima_measurements);
86 atomic_long_inc(&ima_htable.len);
87 key = ima_hash_key(entry->digest);
88 hlist_add_head_rcu(&qe->hnext, &ima_htable.queue[key]);
92 static int ima_pcr_extend(const u8 *hash)
99 result = tpm_pcr_extend(TPM_ANY_NUM, CONFIG_IMA_MEASURE_PCR_IDX, hash);
101 pr_err("Error Communicating to TPM chip, result: %d\n", result);
105 /* Add template entry to the measurement list and hash table,
106 * and extend the pcr.
108 int ima_add_template_entry(struct ima_template_entry *entry, int violation,
109 const char *op, struct inode *inode,
110 const unsigned char *filename)
112 u8 digest[TPM_DIGEST_SIZE];
113 const char *audit_cause = "hash_added";
114 char tpm_audit_cause[AUDIT_CAUSE_LEN_MAX];
116 int result = 0, tpmresult = 0;
118 mutex_lock(&ima_extend_list_mutex);
120 memcpy(digest, entry->digest, sizeof(digest));
121 if (ima_lookup_digest_entry(digest)) {
122 audit_cause = "hash_exists";
128 result = ima_add_digest_entry(entry);
130 audit_cause = "ENOMEM";
135 if (violation) /* invalidate pcr */
136 memset(digest, 0xff, sizeof(digest));
138 tpmresult = ima_pcr_extend(digest);
139 if (tpmresult != 0) {
140 snprintf(tpm_audit_cause, AUDIT_CAUSE_LEN_MAX, "TPM_error(%d)",
142 audit_cause = tpm_audit_cause;
146 mutex_unlock(&ima_extend_list_mutex);
147 integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, filename,
148 op, audit_cause, result, audit_info);