Commit | Line | Data |
---|---|---|
3323eec9 MZ |
1 | /* |
2 | * Copyright (C) 2005,2006,2007,2008 IBM Corporation | |
3 | * | |
4 | * Authors: | |
5 | * Serge Hallyn <serue@us.ibm.com> | |
6 | * Reiner Sailer <sailer@watson.ibm.com> | |
7 | * Mimi Zohar <zohar@us.ibm.com> | |
8 | * | |
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. | |
13 | * | |
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. | |
20 | */ | |
21 | #include <linux/module.h> | |
22 | #include <linux/rculist.h> | |
5a0e3ad6 | 23 | #include <linux/slab.h> |
3323eec9 MZ |
24 | #include "ima.h" |
25 | ||
7b7e5916 RS |
26 | #define AUDIT_CAUSE_LEN_MAX 32 |
27 | ||
3323eec9 MZ |
28 | LIST_HEAD(ima_measurements); /* list of all measurements */ |
29 | ||
30 | /* key: inode (before secure-hashing a file) */ | |
31 | struct ima_h_table ima_htable = { | |
32 | .len = ATOMIC_LONG_INIT(0), | |
33 | .violations = ATOMIC_LONG_INIT(0), | |
34 | .queue[0 ... IMA_MEASURE_HTABLE_SIZE - 1] = HLIST_HEAD_INIT | |
35 | }; | |
36 | ||
37 | /* mutex protects atomicity of extending measurement list | |
38 | * and extending the TPM PCR aggregate. Since tpm_extend can take | |
39 | * long (and the tpm driver uses a mutex), we can't use the spinlock. | |
40 | */ | |
41 | static DEFINE_MUTEX(ima_extend_list_mutex); | |
42 | ||
43 | /* lookup up the digest value in the hash table, and return the entry */ | |
44 | static struct ima_queue_entry *ima_lookup_digest_entry(u8 *digest_value) | |
45 | { | |
46 | struct ima_queue_entry *qe, *ret = NULL; | |
47 | unsigned int key; | |
3323eec9 MZ |
48 | int rc; |
49 | ||
50 | key = ima_hash_key(digest_value); | |
51 | rcu_read_lock(); | |
b67bfe0d | 52 | hlist_for_each_entry_rcu(qe, &ima_htable.queue[key], hnext) { |
3323eec9 MZ |
53 | rc = memcmp(qe->entry->digest, digest_value, IMA_DIGEST_SIZE); |
54 | if (rc == 0) { | |
55 | ret = qe; | |
56 | break; | |
57 | } | |
58 | } | |
59 | rcu_read_unlock(); | |
60 | return ret; | |
61 | } | |
62 | ||
63 | /* ima_add_template_entry helper function: | |
64 | * - Add template entry to measurement list and hash table. | |
65 | * | |
66 | * (Called with ima_extend_list_mutex held.) | |
67 | */ | |
68 | static int ima_add_digest_entry(struct ima_template_entry *entry) | |
69 | { | |
70 | struct ima_queue_entry *qe; | |
71 | unsigned int key; | |
72 | ||
73 | qe = kmalloc(sizeof(*qe), GFP_KERNEL); | |
74 | if (qe == NULL) { | |
eb8dae96 | 75 | pr_err("IMA: OUT OF MEMORY ERROR creating queue entry.\n"); |
3323eec9 MZ |
76 | return -ENOMEM; |
77 | } | |
78 | qe->entry = entry; | |
79 | ||
80 | INIT_LIST_HEAD(&qe->later); | |
81 | list_add_tail_rcu(&qe->later, &ima_measurements); | |
82 | ||
83 | atomic_long_inc(&ima_htable.len); | |
84 | key = ima_hash_key(entry->digest); | |
85 | hlist_add_head_rcu(&qe->hnext, &ima_htable.queue[key]); | |
86 | return 0; | |
87 | } | |
88 | ||
89 | static int ima_pcr_extend(const u8 *hash) | |
90 | { | |
91 | int result = 0; | |
92 | ||
93 | if (!ima_used_chip) | |
94 | return result; | |
95 | ||
96 | result = tpm_pcr_extend(TPM_ANY_NUM, CONFIG_IMA_MEASURE_PCR_IDX, hash); | |
97 | if (result != 0) | |
7b7e5916 RS |
98 | pr_err("IMA: Error Communicating to TPM chip, result: %d\n", |
99 | result); | |
3323eec9 MZ |
100 | return result; |
101 | } | |
102 | ||
103 | /* Add template entry to the measurement list and hash table, | |
104 | * and extend the pcr. | |
105 | */ | |
106 | int ima_add_template_entry(struct ima_template_entry *entry, int violation, | |
107 | const char *op, struct inode *inode) | |
108 | { | |
109 | u8 digest[IMA_DIGEST_SIZE]; | |
110 | const char *audit_cause = "hash_added"; | |
7b7e5916 | 111 | char tpm_audit_cause[AUDIT_CAUSE_LEN_MAX]; |
3323eec9 | 112 | int audit_info = 1; |
7b7e5916 | 113 | int result = 0, tpmresult = 0; |
3323eec9 MZ |
114 | |
115 | mutex_lock(&ima_extend_list_mutex); | |
116 | if (!violation) { | |
117 | memcpy(digest, entry->digest, sizeof digest); | |
118 | if (ima_lookup_digest_entry(digest)) { | |
119 | audit_cause = "hash_exists"; | |
45fae749 | 120 | result = -EEXIST; |
3323eec9 MZ |
121 | goto out; |
122 | } | |
123 | } | |
124 | ||
125 | result = ima_add_digest_entry(entry); | |
126 | if (result < 0) { | |
127 | audit_cause = "ENOMEM"; | |
128 | audit_info = 0; | |
129 | goto out; | |
130 | } | |
131 | ||
132 | if (violation) /* invalidate pcr */ | |
133 | memset(digest, 0xff, sizeof digest); | |
134 | ||
7b7e5916 RS |
135 | tpmresult = ima_pcr_extend(digest); |
136 | if (tpmresult != 0) { | |
137 | snprintf(tpm_audit_cause, AUDIT_CAUSE_LEN_MAX, "TPM_error(%d)", | |
138 | tpmresult); | |
139 | audit_cause = tpm_audit_cause; | |
3323eec9 MZ |
140 | audit_info = 0; |
141 | } | |
142 | out: | |
143 | mutex_unlock(&ima_extend_list_mutex); | |
79b854c5 MZ |
144 | integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, |
145 | entry->template.file_name, | |
3323eec9 MZ |
146 | op, audit_cause, result, audit_info); |
147 | return result; | |
148 | } |