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13#include <linux/module.h>
14#include <linux/list.h>
15#include <linux/security.h>
16#include <linux/magic.h>
17#include <linux/parser.h>
18#include <linux/slab.h>
19#include <linux/genhd.h>
20
21#include "ima.h"
22
23
24#define IMA_FUNC 0x0001
25#define IMA_MASK 0x0002
26#define IMA_FSMAGIC 0x0004
27#define IMA_UID 0x0008
28#define IMA_FOWNER 0x0010
29#define IMA_FSUUID 0x0020
30
31#define UNKNOWN 0
32#define MEASURE 0x0001
33#define DONT_MEASURE 0x0002
34#define APPRAISE 0x0004
35#define DONT_APPRAISE 0x0008
36#define AUDIT 0x0040
37
38#define MAX_LSM_RULES 6
39enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE,
40 LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE
41};
42
43struct ima_rule_entry {
44 struct list_head list;
45 int action;
46 unsigned int flags;
47 enum ima_hooks func;
48 int mask;
49 unsigned long fsmagic;
50 u8 fsuuid[16];
51 kuid_t uid;
52 kuid_t fowner;
53 struct {
54 void *rule;
55 void *args_p;
56 int type;
57 } lsm[MAX_LSM_RULES];
58};
59
60
61
62
63
64
65
66
67
68
69
70
71static struct ima_rule_entry default_rules[] = {
72 {.action = DONT_MEASURE,.fsmagic = PROC_SUPER_MAGIC,.flags = IMA_FSMAGIC},
73 {.action = DONT_MEASURE,.fsmagic = SYSFS_MAGIC,.flags = IMA_FSMAGIC},
74 {.action = DONT_MEASURE,.fsmagic = DEBUGFS_MAGIC,.flags = IMA_FSMAGIC},
75 {.action = DONT_MEASURE,.fsmagic = TMPFS_MAGIC,.flags = IMA_FSMAGIC},
76 {.action = DONT_MEASURE,.fsmagic = RAMFS_MAGIC,.flags = IMA_FSMAGIC},
77 {.action = DONT_MEASURE,.fsmagic = DEVPTS_SUPER_MAGIC,.flags = IMA_FSMAGIC},
78 {.action = DONT_MEASURE,.fsmagic = BINFMTFS_MAGIC,.flags = IMA_FSMAGIC},
79 {.action = DONT_MEASURE,.fsmagic = SECURITYFS_MAGIC,.flags = IMA_FSMAGIC},
80 {.action = DONT_MEASURE,.fsmagic = SELINUX_MAGIC,.flags = IMA_FSMAGIC},
81 {.action = MEASURE,.func = MMAP_CHECK,.mask = MAY_EXEC,
82 .flags = IMA_FUNC | IMA_MASK},
83 {.action = MEASURE,.func = BPRM_CHECK,.mask = MAY_EXEC,
84 .flags = IMA_FUNC | IMA_MASK},
85 {.action = MEASURE,.func = FILE_CHECK,.mask = MAY_READ,.uid = GLOBAL_ROOT_UID,
86 .flags = IMA_FUNC | IMA_MASK | IMA_UID},
87 {.action = MEASURE,.func = MODULE_CHECK, .flags = IMA_FUNC},
88};
89
90static struct ima_rule_entry default_appraise_rules[] = {
91 {.action = DONT_APPRAISE,.fsmagic = PROC_SUPER_MAGIC,.flags = IMA_FSMAGIC},
92 {.action = DONT_APPRAISE,.fsmagic = SYSFS_MAGIC,.flags = IMA_FSMAGIC},
93 {.action = DONT_APPRAISE,.fsmagic = DEBUGFS_MAGIC,.flags = IMA_FSMAGIC},
94 {.action = DONT_APPRAISE,.fsmagic = TMPFS_MAGIC,.flags = IMA_FSMAGIC},
95 {.action = DONT_APPRAISE,.fsmagic = RAMFS_MAGIC,.flags = IMA_FSMAGIC},
96 {.action = DONT_APPRAISE,.fsmagic = DEVPTS_SUPER_MAGIC,.flags = IMA_FSMAGIC},
97 {.action = DONT_APPRAISE,.fsmagic = BINFMTFS_MAGIC,.flags = IMA_FSMAGIC},
98 {.action = DONT_APPRAISE,.fsmagic = SECURITYFS_MAGIC,.flags = IMA_FSMAGIC},
99 {.action = DONT_APPRAISE,.fsmagic = SELINUX_MAGIC,.flags = IMA_FSMAGIC},
100 {.action = DONT_APPRAISE,.fsmagic = CGROUP_SUPER_MAGIC,.flags = IMA_FSMAGIC},
101 {.action = APPRAISE,.fowner = GLOBAL_ROOT_UID,.flags = IMA_FOWNER},
102};
103
104static LIST_HEAD(ima_default_rules);
105static LIST_HEAD(ima_policy_rules);
106static struct list_head *ima_rules;
107
108static DEFINE_MUTEX(ima_rules_mutex);
109
110static bool ima_use_tcb __initdata;
111static int __init default_measure_policy_setup(char *str)
112{
113 ima_use_tcb = 1;
114 return 1;
115}
116__setup("ima_tcb", default_measure_policy_setup);
117
118static bool ima_use_appraise_tcb __initdata;
119static int __init default_appraise_policy_setup(char *str)
120{
121 ima_use_appraise_tcb = 1;
122 return 1;
123}
124__setup("ima_appraise_tcb", default_appraise_policy_setup);
125
126
127
128
129
130
131
132
133
134static void ima_lsm_update_rules(void)
135{
136 struct ima_rule_entry *entry, *tmp;
137 int result;
138 int i;
139
140 mutex_lock(&ima_rules_mutex);
141 list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) {
142 for (i = 0; i < MAX_LSM_RULES; i++) {
143 if (!entry->lsm[i].rule)
144 continue;
145 result = security_filter_rule_init(entry->lsm[i].type,
146 Audit_equal,
147 entry->lsm[i].args_p,
148 &entry->lsm[i].rule);
149 BUG_ON(!entry->lsm[i].rule);
150 }
151 }
152 mutex_unlock(&ima_rules_mutex);
153}
154
155
156
157
158
159
160
161
162
163
164static bool ima_match_rules(struct ima_rule_entry *rule,
165 struct inode *inode, enum ima_hooks func, int mask)
166{
167 struct task_struct *tsk = current;
168 const struct cred *cred = current_cred();
169 int i;
170
171 if ((rule->flags & IMA_FUNC) && rule->func != func)
172 return false;
173 if ((rule->flags & IMA_MASK) && rule->mask != mask)
174 return false;
175 if ((rule->flags & IMA_FSMAGIC)
176 && rule->fsmagic != inode->i_sb->s_magic)
177 return false;
178 if ((rule->flags & IMA_FSUUID) &&
179 memcmp(rule->fsuuid, inode->i_sb->s_uuid, sizeof(rule->fsuuid)))
180 return false;
181 if ((rule->flags & IMA_UID) && !uid_eq(rule->uid, cred->uid))
182 return false;
183 if ((rule->flags & IMA_FOWNER) && !uid_eq(rule->fowner, inode->i_uid))
184 return false;
185 for (i = 0; i < MAX_LSM_RULES; i++) {
186 int rc = 0;
187 u32 osid, sid;
188 int retried = 0;
189
190 if (!rule->lsm[i].rule)
191 continue;
192retry:
193 switch (i) {
194 case LSM_OBJ_USER:
195 case LSM_OBJ_ROLE:
196 case LSM_OBJ_TYPE:
197 security_inode_getsecid(inode, &osid);
198 rc = security_filter_rule_match(osid,
199 rule->lsm[i].type,
200 Audit_equal,
201 rule->lsm[i].rule,
202 NULL);
203 break;
204 case LSM_SUBJ_USER:
205 case LSM_SUBJ_ROLE:
206 case LSM_SUBJ_TYPE:
207 security_task_getsecid(tsk, &sid);
208 rc = security_filter_rule_match(sid,
209 rule->lsm[i].type,
210 Audit_equal,
211 rule->lsm[i].rule,
212 NULL);
213 default:
214 break;
215 }
216 if ((rc < 0) && (!retried)) {
217 retried = 1;
218 ima_lsm_update_rules();
219 goto retry;
220 }
221 if (!rc)
222 return false;
223 }
224 return true;
225}
226
227
228
229
230
231static int get_subaction(struct ima_rule_entry *rule, int func)
232{
233 if (!(rule->flags & IMA_FUNC))
234 return IMA_FILE_APPRAISE;
235
236 switch(func) {
237 case MMAP_CHECK:
238 return IMA_MMAP_APPRAISE;
239 case BPRM_CHECK:
240 return IMA_BPRM_APPRAISE;
241 case MODULE_CHECK:
242 return IMA_MODULE_APPRAISE;
243 case FILE_CHECK:
244 default:
245 return IMA_FILE_APPRAISE;
246 }
247}
248
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259
260
261
262int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask,
263 int flags)
264{
265 struct ima_rule_entry *entry;
266 int action = 0, actmask = flags | (flags << 1);
267
268 list_for_each_entry(entry, ima_rules, list) {
269
270 if (!(entry->action & actmask))
271 continue;
272
273 if (!ima_match_rules(entry, inode, func, mask))
274 continue;
275
276 action |= entry->flags & IMA_ACTION_FLAGS;
277
278 action |= entry->action & IMA_DO_MASK;
279 if (entry->action & IMA_APPRAISE)
280 action |= get_subaction(entry, func);
281
282 if (entry->action & IMA_DO_MASK)
283 actmask &= ~(entry->action | entry->action << 1);
284 else
285 actmask &= ~(entry->action | entry->action >> 1);
286
287 if (!actmask)
288 break;
289 }
290
291 return action;
292}
293
294
295
296
297
298
299
300void __init ima_init_policy(void)
301{
302 int i, measure_entries, appraise_entries;
303
304
305 measure_entries = ima_use_tcb ? ARRAY_SIZE(default_rules) : 0;
306 appraise_entries = ima_use_appraise_tcb ?
307 ARRAY_SIZE(default_appraise_rules) : 0;
308
309 for (i = 0; i < measure_entries + appraise_entries; i++) {
310 if (i < measure_entries)
311 list_add_tail(&default_rules[i].list,
312 &ima_default_rules);
313 else {
314 int j = i - measure_entries;
315
316 list_add_tail(&default_appraise_rules[j].list,
317 &ima_default_rules);
318 }
319 }
320
321 ima_rules = &ima_default_rules;
322}
323
324
325
326
327
328
329
330
331void ima_update_policy(void)
332{
333 const char *op = "policy_update";
334 const char *cause = "already exists";
335 int result = 1;
336 int audit_info = 0;
337
338 if (ima_rules == &ima_default_rules) {
339 ima_rules = &ima_policy_rules;
340 cause = "complete";
341 result = 0;
342 }
343 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
344 NULL, op, cause, result, audit_info);
345}
346
347enum {
348 Opt_err = -1,
349 Opt_measure = 1, Opt_dont_measure,
350 Opt_appraise, Opt_dont_appraise,
351 Opt_audit,
352 Opt_obj_user, Opt_obj_role, Opt_obj_type,
353 Opt_subj_user, Opt_subj_role, Opt_subj_type,
354 Opt_func, Opt_mask, Opt_fsmagic, Opt_uid, Opt_fowner,
355 Opt_appraise_type, Opt_fsuuid
356};
357
358static match_table_t policy_tokens = {
359 {Opt_measure, "measure"},
360 {Opt_dont_measure, "dont_measure"},
361 {Opt_appraise, "appraise"},
362 {Opt_dont_appraise, "dont_appraise"},
363 {Opt_audit, "audit"},
364 {Opt_obj_user, "obj_user=%s"},
365 {Opt_obj_role, "obj_role=%s"},
366 {Opt_obj_type, "obj_type=%s"},
367 {Opt_subj_user, "subj_user=%s"},
368 {Opt_subj_role, "subj_role=%s"},
369 {Opt_subj_type, "subj_type=%s"},
370 {Opt_func, "func=%s"},
371 {Opt_mask, "mask=%s"},
372 {Opt_fsmagic, "fsmagic=%s"},
373 {Opt_fsuuid, "fsuuid=%s"},
374 {Opt_uid, "uid=%s"},
375 {Opt_fowner, "fowner=%s"},
376 {Opt_appraise_type, "appraise_type=%s"},
377 {Opt_err, NULL}
378};
379
380static int ima_lsm_rule_init(struct ima_rule_entry *entry,
381 substring_t *args, int lsm_rule, int audit_type)
382{
383 int result;
384
385 if (entry->lsm[lsm_rule].rule)
386 return -EINVAL;
387
388 entry->lsm[lsm_rule].args_p = match_strdup(args);
389 if (!entry->lsm[lsm_rule].args_p)
390 return -ENOMEM;
391
392 entry->lsm[lsm_rule].type = audit_type;
393 result = security_filter_rule_init(entry->lsm[lsm_rule].type,
394 Audit_equal,
395 entry->lsm[lsm_rule].args_p,
396 &entry->lsm[lsm_rule].rule);
397 if (!entry->lsm[lsm_rule].rule) {
398 kfree(entry->lsm[lsm_rule].args_p);
399 return -EINVAL;
400 }
401
402 return result;
403}
404
405static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
406{
407 audit_log_format(ab, "%s=", key);
408 audit_log_untrustedstring(ab, value);
409 audit_log_format(ab, " ");
410}
411
412static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
413{
414 struct audit_buffer *ab;
415 char *p;
416 int result = 0;
417
418 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_RULE);
419
420 entry->uid = INVALID_UID;
421 entry->fowner = INVALID_UID;
422 entry->action = UNKNOWN;
423 while ((p = strsep(&rule, " \t")) != NULL) {
424 substring_t args[MAX_OPT_ARGS];
425 int token;
426 unsigned long lnum;
427
428 if (result < 0)
429 break;
430 if ((*p == '\0') || (*p == ' ') || (*p == '\t'))
431 continue;
432 token = match_token(p, policy_tokens, args);
433 switch (token) {
434 case Opt_measure:
435 ima_log_string(ab, "action", "measure");
436
437 if (entry->action != UNKNOWN)
438 result = -EINVAL;
439
440 entry->action = MEASURE;
441 break;
442 case Opt_dont_measure:
443 ima_log_string(ab, "action", "dont_measure");
444
445 if (entry->action != UNKNOWN)
446 result = -EINVAL;
447
448 entry->action = DONT_MEASURE;
449 break;
450 case Opt_appraise:
451 ima_log_string(ab, "action", "appraise");
452
453 if (entry->action != UNKNOWN)
454 result = -EINVAL;
455
456 entry->action = APPRAISE;
457 break;
458 case Opt_dont_appraise:
459 ima_log_string(ab, "action", "dont_appraise");
460
461 if (entry->action != UNKNOWN)
462 result = -EINVAL;
463
464 entry->action = DONT_APPRAISE;
465 break;
466 case Opt_audit:
467 ima_log_string(ab, "action", "audit");
468
469 if (entry->action != UNKNOWN)
470 result = -EINVAL;
471
472 entry->action = AUDIT;
473 break;
474 case Opt_func:
475 ima_log_string(ab, "func", args[0].from);
476
477 if (entry->func)
478 result = -EINVAL;
479
480 if (strcmp(args[0].from, "FILE_CHECK") == 0)
481 entry->func = FILE_CHECK;
482
483 else if (strcmp(args[0].from, "PATH_CHECK") == 0)
484 entry->func = FILE_CHECK;
485 else if (strcmp(args[0].from, "MODULE_CHECK") == 0)
486 entry->func = MODULE_CHECK;
487 else if ((strcmp(args[0].from, "FILE_MMAP") == 0)
488 || (strcmp(args[0].from, "MMAP_CHECK") == 0))
489 entry->func = MMAP_CHECK;
490 else if (strcmp(args[0].from, "BPRM_CHECK") == 0)
491 entry->func = BPRM_CHECK;
492 else
493 result = -EINVAL;
494 if (!result)
495 entry->flags |= IMA_FUNC;
496 break;
497 case Opt_mask:
498 ima_log_string(ab, "mask", args[0].from);
499
500 if (entry->mask)
501 result = -EINVAL;
502
503 if ((strcmp(args[0].from, "MAY_EXEC")) == 0)
504 entry->mask = MAY_EXEC;
505 else if (strcmp(args[0].from, "MAY_WRITE") == 0)
506 entry->mask = MAY_WRITE;
507 else if (strcmp(args[0].from, "MAY_READ") == 0)
508 entry->mask = MAY_READ;
509 else if (strcmp(args[0].from, "MAY_APPEND") == 0)
510 entry->mask = MAY_APPEND;
511 else
512 result = -EINVAL;
513 if (!result)
514 entry->flags |= IMA_MASK;
515 break;
516 case Opt_fsmagic:
517 ima_log_string(ab, "fsmagic", args[0].from);
518
519 if (entry->fsmagic) {
520 result = -EINVAL;
521 break;
522 }
523
524 result = strict_strtoul(args[0].from, 16,
525 &entry->fsmagic);
526 if (!result)
527 entry->flags |= IMA_FSMAGIC;
528 break;
529 case Opt_fsuuid:
530 ima_log_string(ab, "fsuuid", args[0].from);
531
532 if (memchr_inv(entry->fsuuid, 0x00,
533 sizeof(entry->fsuuid))) {
534 result = -EINVAL;
535 break;
536 }
537
538 result = blk_part_pack_uuid(args[0].from,
539 entry->fsuuid);
540 if (!result)
541 entry->flags |= IMA_FSUUID;
542 break;
543 case Opt_uid:
544 ima_log_string(ab, "uid", args[0].from);
545
546 if (uid_valid(entry->uid)) {
547 result = -EINVAL;
548 break;
549 }
550
551 result = strict_strtoul(args[0].from, 10, &lnum);
552 if (!result) {
553 entry->uid = make_kuid(current_user_ns(), (uid_t)lnum);
554 if (!uid_valid(entry->uid) || (((uid_t)lnum) != lnum))
555 result = -EINVAL;
556 else
557 entry->flags |= IMA_UID;
558 }
559 break;
560 case Opt_fowner:
561 ima_log_string(ab, "fowner", args[0].from);
562
563 if (uid_valid(entry->fowner)) {
564 result = -EINVAL;
565 break;
566 }
567
568 result = strict_strtoul(args[0].from, 10, &lnum);
569 if (!result) {
570 entry->fowner = make_kuid(current_user_ns(), (uid_t)lnum);
571 if (!uid_valid(entry->fowner) || (((uid_t)lnum) != lnum))
572 result = -EINVAL;
573 else
574 entry->flags |= IMA_FOWNER;
575 }
576 break;
577 case Opt_obj_user:
578 ima_log_string(ab, "obj_user", args[0].from);
579 result = ima_lsm_rule_init(entry, args,
580 LSM_OBJ_USER,
581 AUDIT_OBJ_USER);
582 break;
583 case Opt_obj_role:
584 ima_log_string(ab, "obj_role", args[0].from);
585 result = ima_lsm_rule_init(entry, args,
586 LSM_OBJ_ROLE,
587 AUDIT_OBJ_ROLE);
588 break;
589 case Opt_obj_type:
590 ima_log_string(ab, "obj_type", args[0].from);
591 result = ima_lsm_rule_init(entry, args,
592 LSM_OBJ_TYPE,
593 AUDIT_OBJ_TYPE);
594 break;
595 case Opt_subj_user:
596 ima_log_string(ab, "subj_user", args[0].from);
597 result = ima_lsm_rule_init(entry, args,
598 LSM_SUBJ_USER,
599 AUDIT_SUBJ_USER);
600 break;
601 case Opt_subj_role:
602 ima_log_string(ab, "subj_role", args[0].from);
603 result = ima_lsm_rule_init(entry, args,
604 LSM_SUBJ_ROLE,
605 AUDIT_SUBJ_ROLE);
606 break;
607 case Opt_subj_type:
608 ima_log_string(ab, "subj_type", args[0].from);
609 result = ima_lsm_rule_init(entry, args,
610 LSM_SUBJ_TYPE,
611 AUDIT_SUBJ_TYPE);
612 break;
613 case Opt_appraise_type:
614 if (entry->action != APPRAISE) {
615 result = -EINVAL;
616 break;
617 }
618
619 ima_log_string(ab, "appraise_type", args[0].from);
620 if ((strcmp(args[0].from, "imasig")) == 0)
621 entry->flags |= IMA_DIGSIG_REQUIRED;
622 else
623 result = -EINVAL;
624 break;
625 case Opt_err:
626 ima_log_string(ab, "UNKNOWN", p);
627 result = -EINVAL;
628 break;
629 }
630 }
631 if (!result && (entry->action == UNKNOWN))
632 result = -EINVAL;
633 else if (entry->func == MODULE_CHECK)
634 ima_appraise |= IMA_APPRAISE_MODULES;
635 audit_log_format(ab, "res=%d", !result);
636 audit_log_end(ab);
637 return result;
638}
639
640
641
642
643
644
645
646
647ssize_t ima_parse_add_rule(char *rule)
648{
649 const char *op = "update_policy";
650 char *p;
651 struct ima_rule_entry *entry;
652 ssize_t result, len;
653 int audit_info = 0;
654
655
656 if (ima_rules != &ima_default_rules) {
657 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
658 NULL, op, "already exists",
659 -EACCES, audit_info);
660 return -EACCES;
661 }
662
663 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
664 if (!entry) {
665 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
666 NULL, op, "-ENOMEM", -ENOMEM, audit_info);
667 return -ENOMEM;
668 }
669
670 INIT_LIST_HEAD(&entry->list);
671
672 p = strsep(&rule, "\n");
673 len = strlen(p) + 1;
674
675 if (*p == '#') {
676 kfree(entry);
677 return len;
678 }
679
680 result = ima_parse_rule(p, entry);
681 if (result) {
682 kfree(entry);
683 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
684 NULL, op, "invalid policy", result,
685 audit_info);
686 return result;
687 }
688
689 mutex_lock(&ima_rules_mutex);
690 list_add_tail(&entry->list, &ima_policy_rules);
691 mutex_unlock(&ima_rules_mutex);
692
693 return len;
694}
695
696
697void ima_delete_rules(void)
698{
699 struct ima_rule_entry *entry, *tmp;
700 int i;
701
702 mutex_lock(&ima_rules_mutex);
703 list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) {
704 for (i = 0; i < MAX_LSM_RULES; i++)
705 kfree(entry->lsm[i].args_p);
706
707 list_del(&entry->list);
708 kfree(entry);
709 }
710 mutex_unlock(&ima_rules_mutex);
711}
712
