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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 */
Eric Parisf850a7c2009-05-12 15:13:55 -040018#include <linux/fcntl.h>
Mimi Zoharbab73932009-02-04 09:06:59 -050019#include <linux/module.h>
20#include <linux/seq_file.h>
21#include <linux/rculist.h>
22#include <linux/rcupdate.h>
Mimi Zohar4af46622009-02-04 09:07:00 -050023#include <linux/parser.h>
Mimi Zoharbab73932009-02-04 09:06:59 -050024
25#include "ima.h"
26
Mimi Zohar4af46622009-02-04 09:07:00 -050027static int valid_policy = 1;
Mimi Zoharbab73932009-02-04 09:06:59 -050028#define TMPBUFLEN 12
29static ssize_t ima_show_htable_value(char __user *buf, size_t count,
30 loff_t *ppos, atomic_long_t *val)
31{
32 char tmpbuf[TMPBUFLEN];
33 ssize_t len;
34
35 len = scnprintf(tmpbuf, TMPBUFLEN, "%li\n", atomic_long_read(val));
36 return simple_read_from_buffer(buf, count, ppos, tmpbuf, len);
37}
38
39static ssize_t ima_show_htable_violations(struct file *filp,
40 char __user *buf,
41 size_t count, loff_t *ppos)
42{
43 return ima_show_htable_value(buf, count, ppos, &ima_htable.violations);
44}
45
46static struct file_operations ima_htable_violations_ops = {
47 .read = ima_show_htable_violations
48};
49
50static ssize_t ima_show_measurements_count(struct file *filp,
51 char __user *buf,
52 size_t count, loff_t *ppos)
53{
54 return ima_show_htable_value(buf, count, ppos, &ima_htable.len);
55
56}
57
58static struct file_operations ima_measurements_count_ops = {
59 .read = ima_show_measurements_count
60};
61
62/* returns pointer to hlist_node */
63static void *ima_measurements_start(struct seq_file *m, loff_t *pos)
64{
65 loff_t l = *pos;
66 struct ima_queue_entry *qe;
67
68 /* we need a lock since pos could point beyond last element */
69 rcu_read_lock();
70 list_for_each_entry_rcu(qe, &ima_measurements, later) {
71 if (!l--) {
72 rcu_read_unlock();
73 return qe;
74 }
75 }
76 rcu_read_unlock();
77 return NULL;
78}
79
80static void *ima_measurements_next(struct seq_file *m, void *v, loff_t *pos)
81{
82 struct ima_queue_entry *qe = v;
83
84 /* lock protects when reading beyond last element
85 * against concurrent list-extension
86 */
87 rcu_read_lock();
Jiri Pirko05725f72009-04-14 20:17:16 +020088 qe = list_entry_rcu(qe->later.next,
89 struct ima_queue_entry, later);
Mimi Zoharbab73932009-02-04 09:06:59 -050090 rcu_read_unlock();
91 (*pos)++;
92
93 return (&qe->later == &ima_measurements) ? NULL : qe;
94}
95
96static void ima_measurements_stop(struct seq_file *m, void *v)
97{
98}
99
100static void ima_putc(struct seq_file *m, void *data, int datalen)
101{
102 while (datalen--)
103 seq_putc(m, *(char *)data++);
104}
105
106/* print format:
107 * 32bit-le=pcr#
108 * char[20]=template digest
109 * 32bit-le=template name size
110 * char[n]=template name
111 * eventdata[n]=template specific data
112 */
113static int ima_measurements_show(struct seq_file *m, void *v)
114{
115 /* the list never shrinks, so we don't need a lock here */
116 struct ima_queue_entry *qe = v;
117 struct ima_template_entry *e;
118 int namelen;
119 u32 pcr = CONFIG_IMA_MEASURE_PCR_IDX;
120
121 /* get entry */
122 e = qe->entry;
123 if (e == NULL)
124 return -1;
125
126 /*
127 * 1st: PCRIndex
128 * PCR used is always the same (config option) in
129 * little-endian format
130 */
131 ima_putc(m, &pcr, sizeof pcr);
132
133 /* 2nd: template digest */
134 ima_putc(m, e->digest, IMA_DIGEST_SIZE);
135
136 /* 3rd: template name size */
137 namelen = strlen(e->template_name);
138 ima_putc(m, &namelen, sizeof namelen);
139
140 /* 4th: template name */
Mimi Zohar523979a2009-02-11 11:12:28 -0500141 ima_putc(m, (void *)e->template_name, namelen);
Mimi Zoharbab73932009-02-04 09:06:59 -0500142
143 /* 5th: template specific data */
144 ima_template_show(m, (struct ima_template_data *)&e->template,
145 IMA_SHOW_BINARY);
146 return 0;
147}
148
149static struct seq_operations ima_measurments_seqops = {
150 .start = ima_measurements_start,
151 .next = ima_measurements_next,
152 .stop = ima_measurements_stop,
153 .show = ima_measurements_show
154};
155
156static int ima_measurements_open(struct inode *inode, struct file *file)
157{
158 return seq_open(file, &ima_measurments_seqops);
159}
160
161static struct file_operations ima_measurements_ops = {
162 .open = ima_measurements_open,
163 .read = seq_read,
164 .llseek = seq_lseek,
165 .release = seq_release,
166};
167
168static void ima_print_digest(struct seq_file *m, u8 *digest)
169{
170 int i;
171
172 for (i = 0; i < IMA_DIGEST_SIZE; i++)
173 seq_printf(m, "%02x", *(digest + i));
174}
175
176void ima_template_show(struct seq_file *m, void *e, enum ima_show_type show)
177{
178 struct ima_template_data *entry = e;
179 int namelen;
180
181 switch (show) {
182 case IMA_SHOW_ASCII:
183 ima_print_digest(m, entry->digest);
184 seq_printf(m, " %s\n", entry->file_name);
185 break;
186 case IMA_SHOW_BINARY:
187 ima_putc(m, entry->digest, IMA_DIGEST_SIZE);
188
189 namelen = strlen(entry->file_name);
190 ima_putc(m, &namelen, sizeof namelen);
191 ima_putc(m, entry->file_name, namelen);
192 default:
193 break;
194 }
195}
196
197/* print in ascii */
198static int ima_ascii_measurements_show(struct seq_file *m, void *v)
199{
200 /* the list never shrinks, so we don't need a lock here */
201 struct ima_queue_entry *qe = v;
202 struct ima_template_entry *e;
203
204 /* get entry */
205 e = qe->entry;
206 if (e == NULL)
207 return -1;
208
209 /* 1st: PCR used (config option) */
210 seq_printf(m, "%2d ", CONFIG_IMA_MEASURE_PCR_IDX);
211
212 /* 2nd: SHA1 template hash */
213 ima_print_digest(m, e->digest);
214
215 /* 3th: template name */
216 seq_printf(m, " %s ", e->template_name);
217
218 /* 4th: template specific data */
219 ima_template_show(m, (struct ima_template_data *)&e->template,
220 IMA_SHOW_ASCII);
221 return 0;
222}
223
224static struct seq_operations ima_ascii_measurements_seqops = {
225 .start = ima_measurements_start,
226 .next = ima_measurements_next,
227 .stop = ima_measurements_stop,
228 .show = ima_ascii_measurements_show
229};
230
231static int ima_ascii_measurements_open(struct inode *inode, struct file *file)
232{
233 return seq_open(file, &ima_ascii_measurements_seqops);
234}
235
236static struct file_operations ima_ascii_measurements_ops = {
237 .open = ima_ascii_measurements_open,
238 .read = seq_read,
239 .llseek = seq_lseek,
240 .release = seq_release,
241};
242
Mimi Zohar4af46622009-02-04 09:07:00 -0500243static ssize_t ima_write_policy(struct file *file, const char __user *buf,
244 size_t datalen, loff_t *ppos)
245{
246 char *data;
247 int rc;
248
249 if (datalen >= PAGE_SIZE)
250 return -ENOMEM;
251 if (*ppos != 0) {
252 /* No partial writes. */
253 return -EINVAL;
254 }
255 data = kmalloc(datalen + 1, GFP_KERNEL);
256 if (!data)
257 return -ENOMEM;
258
259 if (copy_from_user(data, buf, datalen)) {
260 kfree(data);
261 return -EFAULT;
262 }
263 *(data + datalen) = '\0';
264 rc = ima_parse_add_rule(data);
265 if (rc < 0) {
266 datalen = -EINVAL;
267 valid_policy = 0;
268 }
269
270 kfree(data);
271 return datalen;
272}
273
Mimi Zoharbab73932009-02-04 09:06:59 -0500274static struct dentry *ima_dir;
275static struct dentry *binary_runtime_measurements;
276static struct dentry *ascii_runtime_measurements;
277static struct dentry *runtime_measurements_count;
278static struct dentry *violations;
Mimi Zohar4af46622009-02-04 09:07:00 -0500279static struct dentry *ima_policy;
280
Mimi Zoharf4bd8572009-02-04 09:07:01 -0500281static atomic_t policy_opencount = ATOMIC_INIT(1);
282/*
283 * ima_open_policy: sequentialize access to the policy file
284 */
285int ima_open_policy(struct inode * inode, struct file * filp)
286{
Eric Parisf850a7c2009-05-12 15:13:55 -0400287 /* No point in being allowed to open it if you aren't going to write */
288 if (!(filp->f_flags & O_WRONLY))
289 return -EACCES;
Mimi Zoharf4bd8572009-02-04 09:07:01 -0500290 if (atomic_dec_and_test(&policy_opencount))
291 return 0;
292 return -EBUSY;
293}
294
Mimi Zohar4af46622009-02-04 09:07:00 -0500295/*
296 * ima_release_policy - start using the new measure policy rules.
297 *
298 * Initially, ima_measure points to the default policy rules, now
Mimi Zoharf4bd8572009-02-04 09:07:01 -0500299 * point to the new policy rules, and remove the securityfs policy file,
300 * assuming a valid policy.
Mimi Zohar4af46622009-02-04 09:07:00 -0500301 */
302static int ima_release_policy(struct inode *inode, struct file *file)
303{
304 if (!valid_policy) {
305 ima_delete_rules();
Mimi Zoharf4bd8572009-02-04 09:07:01 -0500306 valid_policy = 1;
307 atomic_set(&policy_opencount, 1);
Mimi Zohar4af46622009-02-04 09:07:00 -0500308 return 0;
309 }
310 ima_update_policy();
311 securityfs_remove(ima_policy);
312 ima_policy = NULL;
313 return 0;
314}
315
316static struct file_operations ima_measure_policy_ops = {
Mimi Zoharf4bd8572009-02-04 09:07:01 -0500317 .open = ima_open_policy,
Mimi Zohar4af46622009-02-04 09:07:00 -0500318 .write = ima_write_policy,
319 .release = ima_release_policy
320};
Mimi Zoharbab73932009-02-04 09:06:59 -0500321
Eric Paris932995f2009-05-21 15:43:32 -0400322int __init ima_fs_init(void)
Mimi Zoharbab73932009-02-04 09:06:59 -0500323{
324 ima_dir = securityfs_create_dir("ima", NULL);
325 if (IS_ERR(ima_dir))
326 return -1;
327
328 binary_runtime_measurements =
329 securityfs_create_file("binary_runtime_measurements",
330 S_IRUSR | S_IRGRP, ima_dir, NULL,
331 &ima_measurements_ops);
332 if (IS_ERR(binary_runtime_measurements))
333 goto out;
334
335 ascii_runtime_measurements =
336 securityfs_create_file("ascii_runtime_measurements",
337 S_IRUSR | S_IRGRP, ima_dir, NULL,
338 &ima_ascii_measurements_ops);
339 if (IS_ERR(ascii_runtime_measurements))
340 goto out;
341
342 runtime_measurements_count =
343 securityfs_create_file("runtime_measurements_count",
344 S_IRUSR | S_IRGRP, ima_dir, NULL,
345 &ima_measurements_count_ops);
346 if (IS_ERR(runtime_measurements_count))
347 goto out;
348
349 violations =
350 securityfs_create_file("violations", S_IRUSR | S_IRGRP,
351 ima_dir, NULL, &ima_htable_violations_ops);
352 if (IS_ERR(violations))
353 goto out;
354
Mimi Zohar4af46622009-02-04 09:07:00 -0500355 ima_policy = securityfs_create_file("policy",
Eric Parisf850a7c2009-05-12 15:13:55 -0400356 S_IWUSR,
Mimi Zohar4af46622009-02-04 09:07:00 -0500357 ima_dir, NULL,
358 &ima_measure_policy_ops);
359 if (IS_ERR(ima_policy))
360 goto out;
Mimi Zoharbab73932009-02-04 09:06:59 -0500361
Mimi Zohar4af46622009-02-04 09:07:00 -0500362 return 0;
Mimi Zoharbab73932009-02-04 09:06:59 -0500363out:
364 securityfs_remove(runtime_measurements_count);
365 securityfs_remove(ascii_runtime_measurements);
366 securityfs_remove(binary_runtime_measurements);
367 securityfs_remove(ima_dir);
Mimi Zohar4af46622009-02-04 09:07:00 -0500368 securityfs_remove(ima_policy);
Mimi Zoharbab73932009-02-04 09:06:59 -0500369 return -1;
370}
371
372void __exit ima_fs_cleanup(void)
373{
374 securityfs_remove(violations);
375 securityfs_remove(runtime_measurements_count);
376 securityfs_remove(ascii_runtime_measurements);
377 securityfs_remove(binary_runtime_measurements);
378 securityfs_remove(ima_dir);
Mimi Zohar4af46622009-02-04 09:07:00 -0500379 securityfs_remove(ima_policy);
Mimi Zoharbab73932009-02-04 09:06:59 -0500380}