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b886d83c | 1 | // SPDX-License-Identifier: GPL-2.0-only |
bab73937 MZ |
2 | /* |
3 | * Copyright (C) 2005,2006,2007,2008 IBM Corporation | |
4 | * | |
5 | * Authors: | |
6 | * Kylene Hall <kjhall@us.ibm.com> | |
7 | * Reiner Sailer <sailer@us.ibm.com> | |
8 | * Mimi Zohar <zohar@us.ibm.com> | |
9 | * | |
bab73937 MZ |
10 | * File: ima_fs.c |
11 | * implemenents security file system for reporting | |
12 | * current measurement list and IMA statistics | |
13 | */ | |
de636769 | 14 | |
f850a7c0 | 15 | #include <linux/fcntl.h> |
5a0e3ad6 | 16 | #include <linux/slab.h> |
876979c9 | 17 | #include <linux/init.h> |
bab73937 MZ |
18 | #include <linux/seq_file.h> |
19 | #include <linux/rculist.h> | |
20 | #include <linux/rcupdate.h> | |
4af4662f | 21 | #include <linux/parser.h> |
7429b092 | 22 | #include <linux/vmalloc.h> |
bab73937 MZ |
23 | |
24 | #include "ima.h" | |
25 | ||
38d859f9 PM |
26 | static DEFINE_MUTEX(ima_write_mutex); |
27 | ||
d68a6fe9 MZ |
28 | bool ima_canonical_fmt; |
29 | static int __init default_canonical_fmt_setup(char *str) | |
30 | { | |
31 | #ifdef __BIG_ENDIAN | |
39adb925 | 32 | ima_canonical_fmt = true; |
d68a6fe9 MZ |
33 | #endif |
34 | return 1; | |
35 | } | |
36 | __setup("ima_canonical_fmt", default_canonical_fmt_setup); | |
37 | ||
4af4662f | 38 | static int valid_policy = 1; |
1e4c8daf | 39 | |
bab73937 MZ |
40 | static ssize_t ima_show_htable_value(char __user *buf, size_t count, |
41 | loff_t *ppos, atomic_long_t *val) | |
42 | { | |
1e4c8daf | 43 | char tmpbuf[32]; /* greater than largest 'long' string value */ |
bab73937 MZ |
44 | ssize_t len; |
45 | ||
1e4c8daf | 46 | len = scnprintf(tmpbuf, sizeof(tmpbuf), "%li\n", atomic_long_read(val)); |
bab73937 MZ |
47 | return simple_read_from_buffer(buf, count, ppos, tmpbuf, len); |
48 | } | |
49 | ||
50 | static ssize_t ima_show_htable_violations(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.violations); | |
55 | } | |
56 | ||
828c0950 | 57 | static const struct file_operations ima_htable_violations_ops = { |
cdcd90f9 AB |
58 | .read = ima_show_htable_violations, |
59 | .llseek = generic_file_llseek, | |
bab73937 MZ |
60 | }; |
61 | ||
62 | static ssize_t ima_show_measurements_count(struct file *filp, | |
63 | char __user *buf, | |
64 | size_t count, loff_t *ppos) | |
65 | { | |
66 | return ima_show_htable_value(buf, count, ppos, &ima_htable.len); | |
67 | ||
68 | } | |
69 | ||
828c0950 | 70 | static const struct file_operations ima_measurements_count_ops = { |
cdcd90f9 AB |
71 | .read = ima_show_measurements_count, |
72 | .llseek = generic_file_llseek, | |
bab73937 MZ |
73 | }; |
74 | ||
75 | /* returns pointer to hlist_node */ | |
76 | static void *ima_measurements_start(struct seq_file *m, loff_t *pos) | |
77 | { | |
78 | loff_t l = *pos; | |
79 | struct ima_queue_entry *qe; | |
80 | ||
81 | /* we need a lock since pos could point beyond last element */ | |
82 | rcu_read_lock(); | |
83 | list_for_each_entry_rcu(qe, &ima_measurements, later) { | |
84 | if (!l--) { | |
85 | rcu_read_unlock(); | |
86 | return qe; | |
87 | } | |
88 | } | |
89 | rcu_read_unlock(); | |
90 | return NULL; | |
91 | } | |
92 | ||
93 | static void *ima_measurements_next(struct seq_file *m, void *v, loff_t *pos) | |
94 | { | |
95 | struct ima_queue_entry *qe = v; | |
96 | ||
97 | /* lock protects when reading beyond last element | |
98 | * against concurrent list-extension | |
99 | */ | |
100 | rcu_read_lock(); | |
089bc8e9 | 101 | qe = list_entry_rcu(qe->later.next, struct ima_queue_entry, later); |
bab73937 MZ |
102 | rcu_read_unlock(); |
103 | (*pos)++; | |
104 | ||
105 | return (&qe->later == &ima_measurements) ? NULL : qe; | |
106 | } | |
107 | ||
108 | static void ima_measurements_stop(struct seq_file *m, void *v) | |
109 | { | |
110 | } | |
111 | ||
3ce1217d | 112 | void ima_putc(struct seq_file *m, void *data, int datalen) |
bab73937 MZ |
113 | { |
114 | while (datalen--) | |
115 | seq_putc(m, *(char *)data++); | |
116 | } | |
117 | ||
118 | /* print format: | |
119 | * 32bit-le=pcr# | |
120 | * char[20]=template digest | |
121 | * 32bit-le=template name size | |
122 | * char[n]=template name | |
a71dc65d | 123 | * [eventdata length] |
bab73937 MZ |
124 | * eventdata[n]=template specific data |
125 | */ | |
7b8589cc | 126 | int ima_measurements_show(struct seq_file *m, void *v) |
bab73937 MZ |
127 | { |
128 | /* the list never shrinks, so we don't need a lock here */ | |
129 | struct ima_queue_entry *qe = v; | |
130 | struct ima_template_entry *e; | |
7dbdb420 | 131 | char *template_name; |
d68a6fe9 | 132 | u32 pcr, namelen, template_data_len; /* temporary fields */ |
3e8e5503 | 133 | bool is_ima_template = false; |
a71dc65d | 134 | int i; |
bab73937 MZ |
135 | |
136 | /* get entry */ | |
137 | e = qe->entry; | |
138 | if (e == NULL) | |
139 | return -1; | |
140 | ||
7dbdb420 RS |
141 | template_name = (e->template_desc->name[0] != '\0') ? |
142 | e->template_desc->name : e->template_desc->fmt; | |
143 | ||
bab73937 MZ |
144 | /* |
145 | * 1st: PCRIndex | |
5f6f027b ER |
146 | * PCR used defaults to the same (config option) in |
147 | * little-endian format, unless set in policy | |
bab73937 | 148 | */ |
d68a6fe9 MZ |
149 | pcr = !ima_canonical_fmt ? e->pcr : cpu_to_le32(e->pcr); |
150 | ima_putc(m, &pcr, sizeof(e->pcr)); | |
bab73937 MZ |
151 | |
152 | /* 2nd: template digest */ | |
140d8022 | 153 | ima_putc(m, e->digest, TPM_DIGEST_SIZE); |
bab73937 MZ |
154 | |
155 | /* 3rd: template name size */ | |
d68a6fe9 MZ |
156 | namelen = !ima_canonical_fmt ? strlen(template_name) : |
157 | cpu_to_le32(strlen(template_name)); | |
2bb930ab | 158 | ima_putc(m, &namelen, sizeof(namelen)); |
bab73937 MZ |
159 | |
160 | /* 4th: template name */ | |
d68a6fe9 | 161 | ima_putc(m, template_name, strlen(template_name)); |
a71dc65d RS |
162 | |
163 | /* 5th: template length (except for 'ima' template) */ | |
7dbdb420 | 164 | if (strcmp(template_name, IMA_TEMPLATE_IMA_NAME) == 0) |
3e8e5503 RS |
165 | is_ima_template = true; |
166 | ||
d68a6fe9 MZ |
167 | if (!is_ima_template) { |
168 | template_data_len = !ima_canonical_fmt ? e->template_data_len : | |
169 | cpu_to_le32(e->template_data_len); | |
170 | ima_putc(m, &template_data_len, sizeof(e->template_data_len)); | |
171 | } | |
bab73937 | 172 | |
a71dc65d RS |
173 | /* 6th: template specific data */ |
174 | for (i = 0; i < e->template_desc->num_fields; i++) { | |
3e8e5503 | 175 | enum ima_show_type show = IMA_SHOW_BINARY; |
b2724d58 EB |
176 | const struct ima_template_field *field = |
177 | e->template_desc->fields[i]; | |
3e8e5503 RS |
178 | |
179 | if (is_ima_template && strcmp(field->field_id, "d") == 0) | |
180 | show = IMA_SHOW_BINARY_NO_FIELD_LEN; | |
c019e307 RS |
181 | if (is_ima_template && strcmp(field->field_id, "n") == 0) |
182 | show = IMA_SHOW_BINARY_OLD_STRING_FMT; | |
3e8e5503 | 183 | field->field_show(m, show, &e->template_data[i]); |
a71dc65d | 184 | } |
bab73937 MZ |
185 | return 0; |
186 | } | |
187 | ||
88e9d34c | 188 | static const struct seq_operations ima_measurments_seqops = { |
bab73937 MZ |
189 | .start = ima_measurements_start, |
190 | .next = ima_measurements_next, | |
191 | .stop = ima_measurements_stop, | |
192 | .show = ima_measurements_show | |
193 | }; | |
194 | ||
195 | static int ima_measurements_open(struct inode *inode, struct file *file) | |
196 | { | |
197 | return seq_open(file, &ima_measurments_seqops); | |
198 | } | |
199 | ||
828c0950 | 200 | static const struct file_operations ima_measurements_ops = { |
bab73937 MZ |
201 | .open = ima_measurements_open, |
202 | .read = seq_read, | |
203 | .llseek = seq_lseek, | |
204 | .release = seq_release, | |
205 | }; | |
206 | ||
45b26133 | 207 | void ima_print_digest(struct seq_file *m, u8 *digest, u32 size) |
bab73937 | 208 | { |
45b26133 | 209 | u32 i; |
bab73937 | 210 | |
140d8022 | 211 | for (i = 0; i < size; i++) |
bab73937 MZ |
212 | seq_printf(m, "%02x", *(digest + i)); |
213 | } | |
214 | ||
bab73937 MZ |
215 | /* print in ascii */ |
216 | static int ima_ascii_measurements_show(struct seq_file *m, void *v) | |
217 | { | |
218 | /* the list never shrinks, so we don't need a lock here */ | |
219 | struct ima_queue_entry *qe = v; | |
220 | struct ima_template_entry *e; | |
7dbdb420 | 221 | char *template_name; |
a71dc65d | 222 | int i; |
bab73937 MZ |
223 | |
224 | /* get entry */ | |
225 | e = qe->entry; | |
226 | if (e == NULL) | |
227 | return -1; | |
228 | ||
7dbdb420 RS |
229 | template_name = (e->template_desc->name[0] != '\0') ? |
230 | e->template_desc->name : e->template_desc->fmt; | |
231 | ||
bab73937 | 232 | /* 1st: PCR used (config option) */ |
5f6f027b | 233 | seq_printf(m, "%2d ", e->pcr); |
bab73937 MZ |
234 | |
235 | /* 2nd: SHA1 template hash */ | |
140d8022 | 236 | ima_print_digest(m, e->digest, TPM_DIGEST_SIZE); |
bab73937 MZ |
237 | |
238 | /* 3th: template name */ | |
7dbdb420 | 239 | seq_printf(m, " %s", template_name); |
bab73937 MZ |
240 | |
241 | /* 4th: template specific data */ | |
a71dc65d RS |
242 | for (i = 0; i < e->template_desc->num_fields; i++) { |
243 | seq_puts(m, " "); | |
244 | if (e->template_data[i].len == 0) | |
245 | continue; | |
246 | ||
247 | e->template_desc->fields[i]->field_show(m, IMA_SHOW_ASCII, | |
248 | &e->template_data[i]); | |
249 | } | |
250 | seq_puts(m, "\n"); | |
bab73937 MZ |
251 | return 0; |
252 | } | |
253 | ||
88e9d34c | 254 | static const struct seq_operations ima_ascii_measurements_seqops = { |
bab73937 MZ |
255 | .start = ima_measurements_start, |
256 | .next = ima_measurements_next, | |
257 | .stop = ima_measurements_stop, | |
258 | .show = ima_ascii_measurements_show | |
259 | }; | |
260 | ||
261 | static int ima_ascii_measurements_open(struct inode *inode, struct file *file) | |
262 | { | |
263 | return seq_open(file, &ima_ascii_measurements_seqops); | |
264 | } | |
265 | ||
828c0950 | 266 | static const struct file_operations ima_ascii_measurements_ops = { |
bab73937 MZ |
267 | .open = ima_ascii_measurements_open, |
268 | .read = seq_read, | |
269 | .llseek = seq_lseek, | |
270 | .release = seq_release, | |
271 | }; | |
272 | ||
7429b092 DK |
273 | static ssize_t ima_read_policy(char *path) |
274 | { | |
275 | void *data; | |
276 | char *datap; | |
277 | loff_t size; | |
278 | int rc, pathlen = strlen(path); | |
279 | ||
280 | char *p; | |
281 | ||
282 | /* remove \n */ | |
283 | datap = path; | |
284 | strsep(&datap, "\n"); | |
285 | ||
286 | rc = kernel_read_file_from_path(path, &data, &size, 0, READING_POLICY); | |
287 | if (rc < 0) { | |
288 | pr_err("Unable to open file: %s (%d)", path, rc); | |
289 | return rc; | |
290 | } | |
291 | ||
292 | datap = data; | |
293 | while (size > 0 && (p = strsep(&datap, "\n"))) { | |
294 | pr_debug("rule: %s\n", p); | |
295 | rc = ima_parse_add_rule(p); | |
296 | if (rc < 0) | |
297 | break; | |
298 | size -= rc; | |
299 | } | |
300 | ||
301 | vfree(data); | |
302 | if (rc < 0) | |
303 | return rc; | |
304 | else if (size) | |
305 | return -EINVAL; | |
306 | else | |
307 | return pathlen; | |
308 | } | |
309 | ||
4af4662f MZ |
310 | static ssize_t ima_write_policy(struct file *file, const char __user *buf, |
311 | size_t datalen, loff_t *ppos) | |
312 | { | |
6427e6c7 | 313 | char *data; |
6ccd0456 | 314 | ssize_t result; |
4af4662f MZ |
315 | |
316 | if (datalen >= PAGE_SIZE) | |
6ccd0456 EP |
317 | datalen = PAGE_SIZE - 1; |
318 | ||
319 | /* No partial writes. */ | |
320 | result = -EINVAL; | |
321 | if (*ppos != 0) | |
322 | goto out; | |
323 | ||
b4e28030 GT |
324 | data = memdup_user_nul(buf, datalen); |
325 | if (IS_ERR(data)) { | |
326 | result = PTR_ERR(data); | |
6ccd0456 | 327 | goto out; |
b4e28030 | 328 | } |
6ccd0456 | 329 | |
6427e6c7 PM |
330 | result = mutex_lock_interruptible(&ima_write_mutex); |
331 | if (result < 0) | |
332 | goto out_free; | |
6427e6c7 | 333 | |
19f8a847 | 334 | if (data[0] == '/') { |
7429b092 | 335 | result = ima_read_policy(data); |
19f8a847 | 336 | } else if (ima_appraise & IMA_APPRAISE_POLICY) { |
de636769 | 337 | pr_err("signed policy file (specified as an absolute pathname) required\n"); |
19f8a847 MZ |
338 | integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, NULL, |
339 | "policy_update", "signed policy required", | |
340 | 1, 0); | |
2e3a34e9 | 341 | result = -EACCES; |
19f8a847 | 342 | } else { |
7429b092 | 343 | result = ima_parse_add_rule(data); |
19f8a847 | 344 | } |
7429b092 | 345 | mutex_unlock(&ima_write_mutex); |
6427e6c7 PM |
346 | out_free: |
347 | kfree(data); | |
6ccd0456 EP |
348 | out: |
349 | if (result < 0) | |
350 | valid_policy = 0; | |
38d859f9 | 351 | |
6ccd0456 | 352 | return result; |
4af4662f MZ |
353 | } |
354 | ||
bab73937 | 355 | static struct dentry *ima_dir; |
0c343af8 | 356 | static struct dentry *ima_symlink; |
bab73937 MZ |
357 | static struct dentry *binary_runtime_measurements; |
358 | static struct dentry *ascii_runtime_measurements; | |
359 | static struct dentry *runtime_measurements_count; | |
360 | static struct dentry *violations; | |
4af4662f MZ |
361 | static struct dentry *ima_policy; |
362 | ||
0716abbb DK |
363 | enum ima_fs_flags { |
364 | IMA_FS_BUSY, | |
365 | }; | |
366 | ||
367 | static unsigned long ima_fs_flags; | |
368 | ||
80eae209 PM |
369 | #ifdef CONFIG_IMA_READ_POLICY |
370 | static const struct seq_operations ima_policy_seqops = { | |
371 | .start = ima_policy_start, | |
372 | .next = ima_policy_next, | |
373 | .stop = ima_policy_stop, | |
374 | .show = ima_policy_show, | |
375 | }; | |
376 | #endif | |
377 | ||
f4bd857b MZ |
378 | /* |
379 | * ima_open_policy: sequentialize access to the policy file | |
380 | */ | |
2bb930ab | 381 | static int ima_open_policy(struct inode *inode, struct file *filp) |
f4bd857b | 382 | { |
80eae209 PM |
383 | if (!(filp->f_flags & O_WRONLY)) { |
384 | #ifndef CONFIG_IMA_READ_POLICY | |
f850a7c0 | 385 | return -EACCES; |
80eae209 PM |
386 | #else |
387 | if ((filp->f_flags & O_ACCMODE) != O_RDONLY) | |
388 | return -EACCES; | |
389 | if (!capable(CAP_SYS_ADMIN)) | |
390 | return -EPERM; | |
391 | return seq_open(filp, &ima_policy_seqops); | |
392 | #endif | |
393 | } | |
0716abbb DK |
394 | if (test_and_set_bit(IMA_FS_BUSY, &ima_fs_flags)) |
395 | return -EBUSY; | |
396 | return 0; | |
f4bd857b MZ |
397 | } |
398 | ||
4af4662f MZ |
399 | /* |
400 | * ima_release_policy - start using the new measure policy rules. | |
401 | * | |
402 | * Initially, ima_measure points to the default policy rules, now | |
f4bd857b MZ |
403 | * point to the new policy rules, and remove the securityfs policy file, |
404 | * assuming a valid policy. | |
4af4662f MZ |
405 | */ |
406 | static int ima_release_policy(struct inode *inode, struct file *file) | |
407 | { | |
0716abbb DK |
408 | const char *cause = valid_policy ? "completed" : "failed"; |
409 | ||
80eae209 | 410 | if ((file->f_flags & O_ACCMODE) == O_RDONLY) |
9a11a189 | 411 | return seq_release(inode, file); |
80eae209 | 412 | |
0112721d SL |
413 | if (valid_policy && ima_check_policy() < 0) { |
414 | cause = "failed"; | |
415 | valid_policy = 0; | |
416 | } | |
417 | ||
de636769 | 418 | pr_info("policy update %s\n", cause); |
0716abbb DK |
419 | integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, NULL, |
420 | "policy_update", cause, !valid_policy, 0); | |
421 | ||
4af4662f MZ |
422 | if (!valid_policy) { |
423 | ima_delete_rules(); | |
f4bd857b | 424 | valid_policy = 1; |
0716abbb | 425 | clear_bit(IMA_FS_BUSY, &ima_fs_flags); |
4af4662f MZ |
426 | return 0; |
427 | } | |
80eae209 | 428 | |
4af4662f | 429 | ima_update_policy(); |
2068626d | 430 | #if !defined(CONFIG_IMA_WRITE_POLICY) && !defined(CONFIG_IMA_READ_POLICY) |
4af4662f MZ |
431 | securityfs_remove(ima_policy); |
432 | ima_policy = NULL; | |
2068626d | 433 | #elif defined(CONFIG_IMA_WRITE_POLICY) |
38d859f9 | 434 | clear_bit(IMA_FS_BUSY, &ima_fs_flags); |
ffb122de PV |
435 | #elif defined(CONFIG_IMA_READ_POLICY) |
436 | inode->i_mode &= ~S_IWUSR; | |
38d859f9 | 437 | #endif |
4af4662f MZ |
438 | return 0; |
439 | } | |
440 | ||
828c0950 | 441 | static const struct file_operations ima_measure_policy_ops = { |
f4bd857b | 442 | .open = ima_open_policy, |
4af4662f | 443 | .write = ima_write_policy, |
80eae209 | 444 | .read = seq_read, |
cdcd90f9 AB |
445 | .release = ima_release_policy, |
446 | .llseek = generic_file_llseek, | |
4af4662f | 447 | }; |
bab73937 | 448 | |
932995f0 | 449 | int __init ima_fs_init(void) |
bab73937 | 450 | { |
0c343af8 | 451 | ima_dir = securityfs_create_dir("ima", integrity_dir); |
bab73937 MZ |
452 | if (IS_ERR(ima_dir)) |
453 | return -1; | |
454 | ||
0c343af8 MG |
455 | ima_symlink = securityfs_create_symlink("ima", NULL, "integrity/ima", |
456 | NULL); | |
457 | if (IS_ERR(ima_symlink)) | |
458 | goto out; | |
459 | ||
bab73937 MZ |
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); | |
0c343af8 | 499 | securityfs_remove(ima_symlink); |
bab73937 | 500 | securityfs_remove(ima_dir); |
4af4662f | 501 | securityfs_remove(ima_policy); |
bab73937 MZ |
502 | return -1; |
503 | } |