blob: ffbe259700b10b54852cc5d4b29ae91a754230e4 [file] [log] [blame]
Mimi Zoharbab73932009-02-04 09:06:59 -05001/*
2 * Copyright (C) 2005,2006,2007,2008 IBM Corporation
3 *
4 * Authors:
5 * Kylene Hall <kjhall@us.ibm.com>
6 * Reiner Sailer <sailer@us.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_fs.c
15 * implemenents security file system for reporting
16 * current measurement list and IMA statistics
17 */
18#include <linux/module.h>
19#include <linux/seq_file.h>
20#include <linux/rculist.h>
21#include <linux/rcupdate.h>
Mimi Zohar4af46622009-02-04 09:07:00 -050022#include <linux/parser.h>
Mimi Zoharbab73932009-02-04 09:06:59 -050023
24#include "ima.h"
25
Mimi Zohar4af46622009-02-04 09:07:00 -050026static int valid_policy = 1;
Mimi Zoharbab73932009-02-04 09:06:59 -050027#define TMPBUFLEN 12
28static ssize_t ima_show_htable_value(char __user *buf, size_t count,
29 loff_t *ppos, atomic_long_t *val)
30{
31 char tmpbuf[TMPBUFLEN];
32 ssize_t len;
33
34 len = scnprintf(tmpbuf, TMPBUFLEN, "%li\n", atomic_long_read(val));
35 return simple_read_from_buffer(buf, count, ppos, tmpbuf, len);
36}
37
38static ssize_t ima_show_htable_violations(struct file *filp,
39 char __user *buf,
40 size_t count, loff_t *ppos)
41{
42 return ima_show_htable_value(buf, count, ppos, &ima_htable.violations);
43}
44
45static struct file_operations ima_htable_violations_ops = {
46 .read = ima_show_htable_violations
47};
48
49static ssize_t ima_show_measurements_count(struct file *filp,
50 char __user *buf,
51 size_t count, loff_t *ppos)
52{
53 return ima_show_htable_value(buf, count, ppos, &ima_htable.len);
54
55}
56
57static struct file_operations ima_measurements_count_ops = {
58 .read = ima_show_measurements_count
59};
60
61/* returns pointer to hlist_node */
62static void *ima_measurements_start(struct seq_file *m, loff_t *pos)
63{
64 loff_t l = *pos;
65 struct ima_queue_entry *qe;
66
67 /* we need a lock since pos could point beyond last element */
68 rcu_read_lock();
69 list_for_each_entry_rcu(qe, &ima_measurements, later) {
70 if (!l--) {
71 rcu_read_unlock();
72 return qe;
73 }
74 }
75 rcu_read_unlock();
76 return NULL;
77}
78
79static void *ima_measurements_next(struct seq_file *m, void *v, loff_t *pos)
80{
81 struct ima_queue_entry *qe = v;
82
83 /* lock protects when reading beyond last element
84 * against concurrent list-extension
85 */
86 rcu_read_lock();
87 qe = list_entry(rcu_dereference(qe->later.next),
88 struct ima_queue_entry, later);
89 rcu_read_unlock();
90 (*pos)++;
91
92 return (&qe->later == &ima_measurements) ? NULL : qe;
93}
94
95static void ima_measurements_stop(struct seq_file *m, void *v)
96{
97}
98
99static void ima_putc(struct seq_file *m, void *data, int datalen)
100{
101 while (datalen--)
102 seq_putc(m, *(char *)data++);
103}
104
105/* print format:
106 * 32bit-le=pcr#
107 * char[20]=template digest
108 * 32bit-le=template name size
109 * char[n]=template name
110 * eventdata[n]=template specific data
111 */
112static int ima_measurements_show(struct seq_file *m, void *v)
113{
114 /* the list never shrinks, so we don't need a lock here */
115 struct ima_queue_entry *qe = v;
116 struct ima_template_entry *e;
117 int namelen;
118 u32 pcr = CONFIG_IMA_MEASURE_PCR_IDX;
119
120 /* get entry */
121 e = qe->entry;
122 if (e == NULL)
123 return -1;
124
125 /*
126 * 1st: PCRIndex
127 * PCR used is always the same (config option) in
128 * little-endian format
129 */
130 ima_putc(m, &pcr, sizeof pcr);
131
132 /* 2nd: template digest */
133 ima_putc(m, e->digest, IMA_DIGEST_SIZE);
134
135 /* 3rd: template name size */
136 namelen = strlen(e->template_name);
137 ima_putc(m, &namelen, sizeof namelen);
138
139 /* 4th: template name */
Mimi Zohar523979a2009-02-11 11:12:28 -0500140 ima_putc(m, (void *)e->template_name, namelen);
Mimi Zoharbab73932009-02-04 09:06:59 -0500141
142 /* 5th: template specific data */
143 ima_template_show(m, (struct ima_template_data *)&e->template,
144 IMA_SHOW_BINARY);
145 return 0;
146}
147
148static struct seq_operations ima_measurments_seqops = {
149 .start = ima_measurements_start,
150 .next = ima_measurements_next,
151 .stop = ima_measurements_stop,
152 .show = ima_measurements_show
153};
154
155static int ima_measurements_open(struct inode *inode, struct file *file)
156{
157 return seq_open(file, &ima_measurments_seqops);
158}
159
160static struct file_operations ima_measurements_ops = {
161 .open = ima_measurements_open,
162 .read = seq_read,
163 .llseek = seq_lseek,
164 .release = seq_release,
165};
166
167static void ima_print_digest(struct seq_file *m, u8 *digest)
168{
169 int i;
170
171 for (i = 0; i < IMA_DIGEST_SIZE; i++)
172 seq_printf(m, "%02x", *(digest + i));
173}
174
175void ima_template_show(struct seq_file *m, void *e, enum ima_show_type show)
176{
177 struct ima_template_data *entry = e;
178 int namelen;
179
180 switch (show) {
181 case IMA_SHOW_ASCII:
182 ima_print_digest(m, entry->digest);
183 seq_printf(m, " %s\n", entry->file_name);
184 break;
185 case IMA_SHOW_BINARY:
186 ima_putc(m, entry->digest, IMA_DIGEST_SIZE);
187
188 namelen = strlen(entry->file_name);
189 ima_putc(m, &namelen, sizeof namelen);
190 ima_putc(m, entry->file_name, namelen);
191 default:
192 break;
193 }
194}
195
196/* print in ascii */
197static int ima_ascii_measurements_show(struct seq_file *m, void *v)
198{
199 /* the list never shrinks, so we don't need a lock here */
200 struct ima_queue_entry *qe = v;
201 struct ima_template_entry *e;
202
203 /* get entry */
204 e = qe->entry;
205 if (e == NULL)
206 return -1;
207
208 /* 1st: PCR used (config option) */
209 seq_printf(m, "%2d ", CONFIG_IMA_MEASURE_PCR_IDX);
210
211 /* 2nd: SHA1 template hash */
212 ima_print_digest(m, e->digest);
213
214 /* 3th: template name */
215 seq_printf(m, " %s ", e->template_name);
216
217 /* 4th: template specific data */
218 ima_template_show(m, (struct ima_template_data *)&e->template,
219 IMA_SHOW_ASCII);
220 return 0;
221}
222
223static struct seq_operations ima_ascii_measurements_seqops = {
224 .start = ima_measurements_start,
225 .next = ima_measurements_next,
226 .stop = ima_measurements_stop,
227 .show = ima_ascii_measurements_show
228};
229
230static int ima_ascii_measurements_open(struct inode *inode, struct file *file)
231{
232 return seq_open(file, &ima_ascii_measurements_seqops);
233}
234
235static struct file_operations ima_ascii_measurements_ops = {
236 .open = ima_ascii_measurements_open,
237 .read = seq_read,
238 .llseek = seq_lseek,
239 .release = seq_release,
240};
241
Mimi Zohar4af46622009-02-04 09:07:00 -0500242static ssize_t ima_write_policy(struct file *file, const char __user *buf,
243 size_t datalen, loff_t *ppos)
244{
245 char *data;
246 int rc;
247
248 if (datalen >= PAGE_SIZE)
249 return -ENOMEM;
250 if (*ppos != 0) {
251 /* No partial writes. */
252 return -EINVAL;
253 }
254 data = kmalloc(datalen + 1, GFP_KERNEL);
255 if (!data)
256 return -ENOMEM;
257
258 if (copy_from_user(data, buf, datalen)) {
259 kfree(data);
260 return -EFAULT;
261 }
262 *(data + datalen) = '\0';
263 rc = ima_parse_add_rule(data);
264 if (rc < 0) {
265 datalen = -EINVAL;
266 valid_policy = 0;
267 }
268
269 kfree(data);
270 return datalen;
271}
272
Mimi Zoharbab73932009-02-04 09:06:59 -0500273static struct dentry *ima_dir;
274static struct dentry *binary_runtime_measurements;
275static struct dentry *ascii_runtime_measurements;
276static struct dentry *runtime_measurements_count;
277static struct dentry *violations;
Mimi Zohar4af46622009-02-04 09:07:00 -0500278static struct dentry *ima_policy;
279
Mimi Zoharf4bd8572009-02-04 09:07:01 -0500280static atomic_t policy_opencount = ATOMIC_INIT(1);
281/*
282 * ima_open_policy: sequentialize access to the policy file
283 */
284int ima_open_policy(struct inode * inode, struct file * filp)
285{
286 if (atomic_dec_and_test(&policy_opencount))
287 return 0;
288 return -EBUSY;
289}
290
Mimi Zohar4af46622009-02-04 09:07:00 -0500291/*
292 * ima_release_policy - start using the new measure policy rules.
293 *
294 * Initially, ima_measure points to the default policy rules, now
Mimi Zoharf4bd8572009-02-04 09:07:01 -0500295 * point to the new policy rules, and remove the securityfs policy file,
296 * assuming a valid policy.
Mimi Zohar4af46622009-02-04 09:07:00 -0500297 */
298static int ima_release_policy(struct inode *inode, struct file *file)
299{
300 if (!valid_policy) {
301 ima_delete_rules();
Mimi Zoharf4bd8572009-02-04 09:07:01 -0500302 valid_policy = 1;
303 atomic_set(&policy_opencount, 1);
Mimi Zohar4af46622009-02-04 09:07:00 -0500304 return 0;
305 }
306 ima_update_policy();
307 securityfs_remove(ima_policy);
308 ima_policy = NULL;
309 return 0;
310}
311
312static struct file_operations ima_measure_policy_ops = {
Mimi Zoharf4bd8572009-02-04 09:07:01 -0500313 .open = ima_open_policy,
Mimi Zohar4af46622009-02-04 09:07:00 -0500314 .write = ima_write_policy,
315 .release = ima_release_policy
316};
Mimi Zoharbab73932009-02-04 09:06:59 -0500317
318int ima_fs_init(void)
319{
320 ima_dir = securityfs_create_dir("ima", NULL);
321 if (IS_ERR(ima_dir))
322 return -1;
323
324 binary_runtime_measurements =
325 securityfs_create_file("binary_runtime_measurements",
326 S_IRUSR | S_IRGRP, ima_dir, NULL,
327 &ima_measurements_ops);
328 if (IS_ERR(binary_runtime_measurements))
329 goto out;
330
331 ascii_runtime_measurements =
332 securityfs_create_file("ascii_runtime_measurements",
333 S_IRUSR | S_IRGRP, ima_dir, NULL,
334 &ima_ascii_measurements_ops);
335 if (IS_ERR(ascii_runtime_measurements))
336 goto out;
337
338 runtime_measurements_count =
339 securityfs_create_file("runtime_measurements_count",
340 S_IRUSR | S_IRGRP, ima_dir, NULL,
341 &ima_measurements_count_ops);
342 if (IS_ERR(runtime_measurements_count))
343 goto out;
344
345 violations =
346 securityfs_create_file("violations", S_IRUSR | S_IRGRP,
347 ima_dir, NULL, &ima_htable_violations_ops);
348 if (IS_ERR(violations))
349 goto out;
350
Mimi Zohar4af46622009-02-04 09:07:00 -0500351 ima_policy = securityfs_create_file("policy",
352 S_IRUSR | S_IRGRP | S_IWUSR,
353 ima_dir, NULL,
354 &ima_measure_policy_ops);
355 if (IS_ERR(ima_policy))
356 goto out;
Mimi Zoharbab73932009-02-04 09:06:59 -0500357
Mimi Zohar4af46622009-02-04 09:07:00 -0500358 return 0;
Mimi Zoharbab73932009-02-04 09:06:59 -0500359out:
360 securityfs_remove(runtime_measurements_count);
361 securityfs_remove(ascii_runtime_measurements);
362 securityfs_remove(binary_runtime_measurements);
363 securityfs_remove(ima_dir);
Mimi Zohar4af46622009-02-04 09:07:00 -0500364 securityfs_remove(ima_policy);
Mimi Zoharbab73932009-02-04 09:06:59 -0500365 return -1;
366}
367
368void __exit ima_fs_cleanup(void)
369{
370 securityfs_remove(violations);
371 securityfs_remove(runtime_measurements_count);
372 securityfs_remove(ascii_runtime_measurements);
373 securityfs_remove(binary_runtime_measurements);
374 securityfs_remove(ima_dir);
Mimi Zohar4af46622009-02-04 09:07:00 -0500375 securityfs_remove(ima_policy);
Mimi Zoharbab73932009-02-04 09:06:59 -0500376}