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Commit | Line | Data |
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bab73937 MZ |
1 | /* |
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 | */ | |
f850a7c0 | 18 | #include <linux/fcntl.h> |
5a0e3ad6 | 19 | #include <linux/slab.h> |
bab73937 MZ |
20 | #include <linux/module.h> |
21 | #include <linux/seq_file.h> | |
22 | #include <linux/rculist.h> | |
23 | #include <linux/rcupdate.h> | |
4af4662f | 24 | #include <linux/parser.h> |
7429b092 | 25 | #include <linux/vmalloc.h> |
bab73937 MZ |
26 | |
27 | #include "ima.h" | |
28 | ||
38d859f9 PM |
29 | static DEFINE_MUTEX(ima_write_mutex); |
30 | ||
d68a6fe9 MZ |
31 | bool ima_canonical_fmt; |
32 | static int __init default_canonical_fmt_setup(char *str) | |
33 | { | |
34 | #ifdef __BIG_ENDIAN | |
35 | ima_canonical_fmt = 1; | |
36 | #endif | |
37 | return 1; | |
38 | } | |
39 | __setup("ima_canonical_fmt", default_canonical_fmt_setup); | |
40 | ||
4af4662f | 41 | static int valid_policy = 1; |
bab73937 MZ |
42 | #define TMPBUFLEN 12 |
43 | static ssize_t ima_show_htable_value(char __user *buf, size_t count, | |
44 | loff_t *ppos, atomic_long_t *val) | |
45 | { | |
46 | char tmpbuf[TMPBUFLEN]; | |
47 | ssize_t len; | |
48 | ||
49 | len = scnprintf(tmpbuf, TMPBUFLEN, "%li\n", atomic_long_read(val)); | |
50 | return simple_read_from_buffer(buf, count, ppos, tmpbuf, len); | |
51 | } | |
52 | ||
53 | static ssize_t ima_show_htable_violations(struct file *filp, | |
54 | char __user *buf, | |
55 | size_t count, loff_t *ppos) | |
56 | { | |
57 | return ima_show_htable_value(buf, count, ppos, &ima_htable.violations); | |
58 | } | |
59 | ||
828c0950 | 60 | static const struct file_operations ima_htable_violations_ops = { |
cdcd90f9 AB |
61 | .read = ima_show_htable_violations, |
62 | .llseek = generic_file_llseek, | |
bab73937 MZ |
63 | }; |
64 | ||
65 | static ssize_t ima_show_measurements_count(struct file *filp, | |
66 | char __user *buf, | |
67 | size_t count, loff_t *ppos) | |
68 | { | |
69 | return ima_show_htable_value(buf, count, ppos, &ima_htable.len); | |
70 | ||
71 | } | |
72 | ||
828c0950 | 73 | static const struct file_operations ima_measurements_count_ops = { |
cdcd90f9 AB |
74 | .read = ima_show_measurements_count, |
75 | .llseek = generic_file_llseek, | |
bab73937 MZ |
76 | }; |
77 | ||
78 | /* returns pointer to hlist_node */ | |
79 | static void *ima_measurements_start(struct seq_file *m, loff_t *pos) | |
80 | { | |
81 | loff_t l = *pos; | |
82 | struct ima_queue_entry *qe; | |
83 | ||
84 | /* we need a lock since pos could point beyond last element */ | |
85 | rcu_read_lock(); | |
86 | list_for_each_entry_rcu(qe, &ima_measurements, later) { | |
87 | if (!l--) { | |
88 | rcu_read_unlock(); | |
89 | return qe; | |
90 | } | |
91 | } | |
92 | rcu_read_unlock(); | |
93 | return NULL; | |
94 | } | |
95 | ||
96 | static void *ima_measurements_next(struct seq_file *m, void *v, loff_t *pos) | |
97 | { | |
98 | struct ima_queue_entry *qe = v; | |
99 | ||
100 | /* lock protects when reading beyond last element | |
101 | * against concurrent list-extension | |
102 | */ | |
103 | rcu_read_lock(); | |
089bc8e9 | 104 | qe = list_entry_rcu(qe->later.next, struct ima_queue_entry, later); |
bab73937 MZ |
105 | rcu_read_unlock(); |
106 | (*pos)++; | |
107 | ||
108 | return (&qe->later == &ima_measurements) ? NULL : qe; | |
109 | } | |
110 | ||
111 | static void ima_measurements_stop(struct seq_file *m, void *v) | |
112 | { | |
113 | } | |
114 | ||
3ce1217d | 115 | void ima_putc(struct seq_file *m, void *data, int datalen) |
bab73937 MZ |
116 | { |
117 | while (datalen--) | |
118 | seq_putc(m, *(char *)data++); | |
119 | } | |
120 | ||
121 | /* print format: | |
122 | * 32bit-le=pcr# | |
123 | * char[20]=template digest | |
124 | * 32bit-le=template name size | |
125 | * char[n]=template name | |
a71dc65d | 126 | * [eventdata length] |
bab73937 MZ |
127 | * eventdata[n]=template specific data |
128 | */ | |
7b8589cc | 129 | int ima_measurements_show(struct seq_file *m, void *v) |
bab73937 MZ |
130 | { |
131 | /* the list never shrinks, so we don't need a lock here */ | |
132 | struct ima_queue_entry *qe = v; | |
133 | struct ima_template_entry *e; | |
7dbdb420 | 134 | char *template_name; |
d68a6fe9 | 135 | u32 pcr, namelen, template_data_len; /* temporary fields */ |
3e8e5503 | 136 | bool is_ima_template = false; |
a71dc65d | 137 | int i; |
bab73937 MZ |
138 | |
139 | /* get entry */ | |
140 | e = qe->entry; | |
141 | if (e == NULL) | |
142 | return -1; | |
143 | ||
7dbdb420 RS |
144 | template_name = (e->template_desc->name[0] != '\0') ? |
145 | e->template_desc->name : e->template_desc->fmt; | |
146 | ||
bab73937 MZ |
147 | /* |
148 | * 1st: PCRIndex | |
5f6f027b ER |
149 | * PCR used defaults to the same (config option) in |
150 | * little-endian format, unless set in policy | |
bab73937 | 151 | */ |
d68a6fe9 MZ |
152 | pcr = !ima_canonical_fmt ? e->pcr : cpu_to_le32(e->pcr); |
153 | ima_putc(m, &pcr, sizeof(e->pcr)); | |
bab73937 MZ |
154 | |
155 | /* 2nd: template digest */ | |
140d8022 | 156 | ima_putc(m, e->digest, TPM_DIGEST_SIZE); |
bab73937 MZ |
157 | |
158 | /* 3rd: template name size */ | |
d68a6fe9 MZ |
159 | namelen = !ima_canonical_fmt ? strlen(template_name) : |
160 | cpu_to_le32(strlen(template_name)); | |
2bb930ab | 161 | ima_putc(m, &namelen, sizeof(namelen)); |
bab73937 MZ |
162 | |
163 | /* 4th: template name */ | |
d68a6fe9 | 164 | ima_putc(m, template_name, strlen(template_name)); |
a71dc65d RS |
165 | |
166 | /* 5th: template length (except for 'ima' template) */ | |
7dbdb420 | 167 | if (strcmp(template_name, IMA_TEMPLATE_IMA_NAME) == 0) |
3e8e5503 RS |
168 | is_ima_template = true; |
169 | ||
d68a6fe9 MZ |
170 | if (!is_ima_template) { |
171 | template_data_len = !ima_canonical_fmt ? e->template_data_len : | |
172 | cpu_to_le32(e->template_data_len); | |
173 | ima_putc(m, &template_data_len, sizeof(e->template_data_len)); | |
174 | } | |
bab73937 | 175 | |
a71dc65d RS |
176 | /* 6th: template specific data */ |
177 | for (i = 0; i < e->template_desc->num_fields; i++) { | |
3e8e5503 RS |
178 | enum ima_show_type show = IMA_SHOW_BINARY; |
179 | struct ima_template_field *field = e->template_desc->fields[i]; | |
180 | ||
181 | if (is_ima_template && strcmp(field->field_id, "d") == 0) | |
182 | show = IMA_SHOW_BINARY_NO_FIELD_LEN; | |
c019e307 RS |
183 | if (is_ima_template && strcmp(field->field_id, "n") == 0) |
184 | show = IMA_SHOW_BINARY_OLD_STRING_FMT; | |
3e8e5503 | 185 | field->field_show(m, show, &e->template_data[i]); |
a71dc65d | 186 | } |
bab73937 MZ |
187 | return 0; |
188 | } | |
189 | ||
88e9d34c | 190 | static const struct seq_operations ima_measurments_seqops = { |
bab73937 MZ |
191 | .start = ima_measurements_start, |
192 | .next = ima_measurements_next, | |
193 | .stop = ima_measurements_stop, | |
194 | .show = ima_measurements_show | |
195 | }; | |
196 | ||
197 | static int ima_measurements_open(struct inode *inode, struct file *file) | |
198 | { | |
199 | return seq_open(file, &ima_measurments_seqops); | |
200 | } | |
201 | ||
828c0950 | 202 | static const struct file_operations ima_measurements_ops = { |
bab73937 MZ |
203 | .open = ima_measurements_open, |
204 | .read = seq_read, | |
205 | .llseek = seq_lseek, | |
206 | .release = seq_release, | |
207 | }; | |
208 | ||
45b26133 | 209 | void ima_print_digest(struct seq_file *m, u8 *digest, u32 size) |
bab73937 | 210 | { |
45b26133 | 211 | u32 i; |
bab73937 | 212 | |
140d8022 | 213 | for (i = 0; i < size; i++) |
bab73937 MZ |
214 | seq_printf(m, "%02x", *(digest + i)); |
215 | } | |
216 | ||
bab73937 MZ |
217 | /* print in ascii */ |
218 | static int ima_ascii_measurements_show(struct seq_file *m, void *v) | |
219 | { | |
220 | /* the list never shrinks, so we don't need a lock here */ | |
221 | struct ima_queue_entry *qe = v; | |
222 | struct ima_template_entry *e; | |
7dbdb420 | 223 | char *template_name; |
a71dc65d | 224 | int i; |
bab73937 MZ |
225 | |
226 | /* get entry */ | |
227 | e = qe->entry; | |
228 | if (e == NULL) | |
229 | return -1; | |
230 | ||
7dbdb420 RS |
231 | template_name = (e->template_desc->name[0] != '\0') ? |
232 | e->template_desc->name : e->template_desc->fmt; | |
233 | ||
bab73937 | 234 | /* 1st: PCR used (config option) */ |
5f6f027b | 235 | seq_printf(m, "%2d ", e->pcr); |
bab73937 MZ |
236 | |
237 | /* 2nd: SHA1 template hash */ | |
140d8022 | 238 | ima_print_digest(m, e->digest, TPM_DIGEST_SIZE); |
bab73937 MZ |
239 | |
240 | /* 3th: template name */ | |
7dbdb420 | 241 | seq_printf(m, " %s", template_name); |
bab73937 MZ |
242 | |
243 | /* 4th: template specific data */ | |
a71dc65d RS |
244 | for (i = 0; i < e->template_desc->num_fields; i++) { |
245 | seq_puts(m, " "); | |
246 | if (e->template_data[i].len == 0) | |
247 | continue; | |
248 | ||
249 | e->template_desc->fields[i]->field_show(m, IMA_SHOW_ASCII, | |
250 | &e->template_data[i]); | |
251 | } | |
252 | seq_puts(m, "\n"); | |
bab73937 MZ |
253 | return 0; |
254 | } | |
255 | ||
88e9d34c | 256 | static const struct seq_operations ima_ascii_measurements_seqops = { |
bab73937 MZ |
257 | .start = ima_measurements_start, |
258 | .next = ima_measurements_next, | |
259 | .stop = ima_measurements_stop, | |
260 | .show = ima_ascii_measurements_show | |
261 | }; | |
262 | ||
263 | static int ima_ascii_measurements_open(struct inode *inode, struct file *file) | |
264 | { | |
265 | return seq_open(file, &ima_ascii_measurements_seqops); | |
266 | } | |
267 | ||
828c0950 | 268 | static const struct file_operations ima_ascii_measurements_ops = { |
bab73937 MZ |
269 | .open = ima_ascii_measurements_open, |
270 | .read = seq_read, | |
271 | .llseek = seq_lseek, | |
272 | .release = seq_release, | |
273 | }; | |
274 | ||
7429b092 DK |
275 | static ssize_t ima_read_policy(char *path) |
276 | { | |
277 | void *data; | |
278 | char *datap; | |
279 | loff_t size; | |
280 | int rc, pathlen = strlen(path); | |
281 | ||
282 | char *p; | |
283 | ||
284 | /* remove \n */ | |
285 | datap = path; | |
286 | strsep(&datap, "\n"); | |
287 | ||
288 | rc = kernel_read_file_from_path(path, &data, &size, 0, READING_POLICY); | |
289 | if (rc < 0) { | |
365d51f2 | 290 | pr_warn("Unable to open file: %s (%d)", path, rc); |
7429b092 DK |
291 | return rc; |
292 | } | |
293 | ||
294 | datap = data; | |
295 | while (size > 0 && (p = strsep(&datap, "\n"))) { | |
296 | pr_debug("rule: %s\n", p); | |
297 | rc = ima_parse_add_rule(p); | |
298 | if (rc < 0) | |
299 | break; | |
300 | size -= rc; | |
301 | } | |
302 | ||
303 | vfree(data); | |
304 | if (rc < 0) | |
305 | return rc; | |
306 | else if (size) | |
307 | return -EINVAL; | |
308 | else | |
309 | return pathlen; | |
310 | } | |
311 | ||
4af4662f MZ |
312 | static ssize_t ima_write_policy(struct file *file, const char __user *buf, |
313 | size_t datalen, loff_t *ppos) | |
314 | { | |
6427e6c7 | 315 | char *data; |
6ccd0456 | 316 | ssize_t result; |
4af4662f MZ |
317 | |
318 | if (datalen >= PAGE_SIZE) | |
6ccd0456 EP |
319 | datalen = PAGE_SIZE - 1; |
320 | ||
321 | /* No partial writes. */ | |
322 | result = -EINVAL; | |
323 | if (*ppos != 0) | |
324 | goto out; | |
325 | ||
326 | result = -ENOMEM; | |
4af4662f MZ |
327 | data = kmalloc(datalen + 1, GFP_KERNEL); |
328 | if (!data) | |
6ccd0456 | 329 | goto out; |
4af4662f | 330 | |
4af4662f | 331 | *(data + datalen) = '\0'; |
4af4662f | 332 | |
6ccd0456 EP |
333 | result = -EFAULT; |
334 | if (copy_from_user(data, buf, datalen)) | |
6427e6c7 | 335 | goto out_free; |
6ccd0456 | 336 | |
6427e6c7 PM |
337 | result = mutex_lock_interruptible(&ima_write_mutex); |
338 | if (result < 0) | |
339 | goto out_free; | |
6427e6c7 | 340 | |
19f8a847 | 341 | if (data[0] == '/') { |
7429b092 | 342 | result = ima_read_policy(data); |
19f8a847 MZ |
343 | } else if (ima_appraise & IMA_APPRAISE_POLICY) { |
344 | pr_err("IMA: signed policy file (specified as an absolute pathname) required\n"); | |
345 | integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, NULL, | |
346 | "policy_update", "signed policy required", | |
347 | 1, 0); | |
348 | if (ima_appraise & IMA_APPRAISE_ENFORCE) | |
349 | result = -EACCES; | |
350 | } else { | |
7429b092 | 351 | result = ima_parse_add_rule(data); |
19f8a847 | 352 | } |
7429b092 | 353 | mutex_unlock(&ima_write_mutex); |
6427e6c7 PM |
354 | out_free: |
355 | kfree(data); | |
6ccd0456 EP |
356 | out: |
357 | if (result < 0) | |
358 | valid_policy = 0; | |
38d859f9 | 359 | |
6ccd0456 | 360 | return result; |
4af4662f MZ |
361 | } |
362 | ||
bab73937 MZ |
363 | static struct dentry *ima_dir; |
364 | static struct dentry *binary_runtime_measurements; | |
365 | static struct dentry *ascii_runtime_measurements; | |
366 | static struct dentry *runtime_measurements_count; | |
367 | static struct dentry *violations; | |
4af4662f MZ |
368 | static struct dentry *ima_policy; |
369 | ||
0716abbb DK |
370 | enum ima_fs_flags { |
371 | IMA_FS_BUSY, | |
372 | }; | |
373 | ||
374 | static unsigned long ima_fs_flags; | |
375 | ||
80eae209 PM |
376 | #ifdef CONFIG_IMA_READ_POLICY |
377 | static const struct seq_operations ima_policy_seqops = { | |
378 | .start = ima_policy_start, | |
379 | .next = ima_policy_next, | |
380 | .stop = ima_policy_stop, | |
381 | .show = ima_policy_show, | |
382 | }; | |
383 | #endif | |
384 | ||
f4bd857b MZ |
385 | /* |
386 | * ima_open_policy: sequentialize access to the policy file | |
387 | */ | |
2bb930ab | 388 | static int ima_open_policy(struct inode *inode, struct file *filp) |
f4bd857b | 389 | { |
80eae209 PM |
390 | if (!(filp->f_flags & O_WRONLY)) { |
391 | #ifndef CONFIG_IMA_READ_POLICY | |
f850a7c0 | 392 | return -EACCES; |
80eae209 PM |
393 | #else |
394 | if ((filp->f_flags & O_ACCMODE) != O_RDONLY) | |
395 | return -EACCES; | |
396 | if (!capable(CAP_SYS_ADMIN)) | |
397 | return -EPERM; | |
398 | return seq_open(filp, &ima_policy_seqops); | |
399 | #endif | |
400 | } | |
0716abbb DK |
401 | if (test_and_set_bit(IMA_FS_BUSY, &ima_fs_flags)) |
402 | return -EBUSY; | |
403 | return 0; | |
f4bd857b MZ |
404 | } |
405 | ||
4af4662f MZ |
406 | /* |
407 | * ima_release_policy - start using the new measure policy rules. | |
408 | * | |
409 | * Initially, ima_measure points to the default policy rules, now | |
f4bd857b MZ |
410 | * point to the new policy rules, and remove the securityfs policy file, |
411 | * assuming a valid policy. | |
4af4662f MZ |
412 | */ |
413 | static int ima_release_policy(struct inode *inode, struct file *file) | |
414 | { | |
0716abbb DK |
415 | const char *cause = valid_policy ? "completed" : "failed"; |
416 | ||
80eae209 | 417 | if ((file->f_flags & O_ACCMODE) == O_RDONLY) |
9a11a189 | 418 | return seq_release(inode, file); |
80eae209 | 419 | |
0112721d SL |
420 | if (valid_policy && ima_check_policy() < 0) { |
421 | cause = "failed"; | |
422 | valid_policy = 0; | |
423 | } | |
424 | ||
0716abbb DK |
425 | pr_info("IMA: policy update %s\n", cause); |
426 | integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, NULL, | |
427 | "policy_update", cause, !valid_policy, 0); | |
428 | ||
4af4662f MZ |
429 | if (!valid_policy) { |
430 | ima_delete_rules(); | |
f4bd857b | 431 | valid_policy = 1; |
0716abbb | 432 | clear_bit(IMA_FS_BUSY, &ima_fs_flags); |
4af4662f MZ |
433 | return 0; |
434 | } | |
80eae209 | 435 | |
4af4662f | 436 | ima_update_policy(); |
38d859f9 | 437 | #ifndef CONFIG_IMA_WRITE_POLICY |
4af4662f MZ |
438 | securityfs_remove(ima_policy); |
439 | ima_policy = NULL; | |
38d859f9 PM |
440 | #else |
441 | clear_bit(IMA_FS_BUSY, &ima_fs_flags); | |
442 | #endif | |
4af4662f MZ |
443 | return 0; |
444 | } | |
445 | ||
828c0950 | 446 | static const struct file_operations ima_measure_policy_ops = { |
f4bd857b | 447 | .open = ima_open_policy, |
4af4662f | 448 | .write = ima_write_policy, |
80eae209 | 449 | .read = seq_read, |
cdcd90f9 AB |
450 | .release = ima_release_policy, |
451 | .llseek = generic_file_llseek, | |
4af4662f | 452 | }; |
bab73937 | 453 | |
932995f0 | 454 | int __init ima_fs_init(void) |
bab73937 MZ |
455 | { |
456 | ima_dir = securityfs_create_dir("ima", NULL); | |
457 | if (IS_ERR(ima_dir)) | |
458 | return -1; | |
459 | ||
460 | binary_runtime_measurements = | |
461 | securityfs_create_file("binary_runtime_measurements", | |
462 | S_IRUSR | S_IRGRP, ima_dir, NULL, | |
463 | &ima_measurements_ops); | |
464 | if (IS_ERR(binary_runtime_measurements)) | |
465 | goto out; | |
466 | ||
467 | ascii_runtime_measurements = | |
468 | securityfs_create_file("ascii_runtime_measurements", | |
469 | S_IRUSR | S_IRGRP, ima_dir, NULL, | |
470 | &ima_ascii_measurements_ops); | |
471 | if (IS_ERR(ascii_runtime_measurements)) | |
472 | goto out; | |
473 | ||
474 | runtime_measurements_count = | |
475 | securityfs_create_file("runtime_measurements_count", | |
476 | S_IRUSR | S_IRGRP, ima_dir, NULL, | |
477 | &ima_measurements_count_ops); | |
478 | if (IS_ERR(runtime_measurements_count)) | |
479 | goto out; | |
480 | ||
481 | violations = | |
482 | securityfs_create_file("violations", S_IRUSR | S_IRGRP, | |
483 | ima_dir, NULL, &ima_htable_violations_ops); | |
484 | if (IS_ERR(violations)) | |
485 | goto out; | |
486 | ||
80eae209 | 487 | ima_policy = securityfs_create_file("policy", POLICY_FILE_FLAGS, |
4af4662f MZ |
488 | ima_dir, NULL, |
489 | &ima_measure_policy_ops); | |
490 | if (IS_ERR(ima_policy)) | |
491 | goto out; | |
bab73937 | 492 | |
4af4662f | 493 | return 0; |
bab73937 | 494 | out: |
0ea4f8ae | 495 | securityfs_remove(violations); |
bab73937 MZ |
496 | securityfs_remove(runtime_measurements_count); |
497 | securityfs_remove(ascii_runtime_measurements); | |
498 | securityfs_remove(binary_runtime_measurements); | |
499 | securityfs_remove(ima_dir); | |
4af4662f | 500 | securityfs_remove(ima_policy); |
bab73937 MZ |
501 | return -1; |
502 | } |