summaryrefslogtreecommitdiffstats
path: root/security/integrity/ima/ima_policy.c
blob: 6f885fab9d84a1476eacaf5d1905b4546d964fd6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
/*
 * Copyright (C) 2008 IBM Corporation
 * Author: Mimi Zohar <zohar@us.ibm.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, version 2 of the License.
 *
 * ima_policy.c
 *	- initialize default measure policy rules
 *
 */
#include <linux/module.h>
#include <linux/list.h>
#include <linux/fs.h>
#include <linux/security.h>
#include <linux/magic.h>
#include <linux/parser.h>
#include <linux/slab.h>
#include <linux/rculist.h>
#include <linux/genhd.h>
#include <linux/seq_file.h>

#include "ima.h"

/* flags definitions */
#define IMA_FUNC	0x0001
#define IMA_MASK	0x0002
#define IMA_FSMAGIC	0x0004
#define IMA_UID		0x0008
#define IMA_FOWNER	0x0010
#define IMA_FSUUID	0x0020
#define IMA_INMASK	0x0040
#define IMA_EUID	0x0080
#define IMA_PCR		0x0100

#define UNKNOWN		0
#define MEASURE		0x0001	/* same as IMA_MEASURE */
#define DONT_MEASURE	0x0002
#define APPRAISE	0x0004	/* same as IMA_APPRAISE */
#define DONT_APPRAISE	0x0008
#define AUDIT		0x0040

#define INVALID_PCR(a) (((a) < 0) || \
	(a) >= (FIELD_SIZEOF(struct integrity_iint_cache, measured_pcrs) * 8))

int ima_policy_flag;
static int temp_ima_appraise;

#define MAX_LSM_RULES 6
enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE,
	LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE
};

enum policy_types { ORIGINAL_TCB = 1, DEFAULT_TCB };

struct ima_rule_entry {
	struct list_head list;
	int action;
	unsigned int flags;
	enum ima_hooks func;
	int mask;
	unsigned long fsmagic;
	uuid_t fsuuid;
	kuid_t uid;
	kuid_t fowner;
	bool (*uid_op)(kuid_t, kuid_t);    /* Handlers for operators       */
	bool (*fowner_op)(kuid_t, kuid_t); /* uid_eq(), uid_gt(), uid_lt() */
	int pcr;
	struct {
		void *rule;	/* LSM file metadata specific */
		void *args_p;	/* audit value */
		int type;	/* audit type */
	} lsm[MAX_LSM_RULES];
};

/*
 * Without LSM specific knowledge, the default policy can only be
 * written in terms of .action, .func, .mask, .fsmagic, .uid, and .fowner
 */

/*
 * The minimum rule set to allow for full TCB coverage.  Measures all files
 * opened or mmap for exec and everything read by root.  Dangerous because
 * normal users can easily run the machine out of memory simply building
 * and running executables.
 */
static struct ima_rule_entry dont_measure_rules[] __ro_after_init = {
	{.action = DONT_MEASURE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
	{.action = DONT_MEASURE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
	{.action = DONT_MEASURE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
	{.action = DONT_MEASURE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
	{.action = DONT_MEASURE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
	{.action = DONT_MEASURE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
	{.action = DONT_MEASURE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
	{.action = DONT_MEASURE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
	{.action = DONT_MEASURE, .fsmagic = CGROUP_SUPER_MAGIC,
	 .flags = IMA_FSMAGIC},
	{.action = DONT_MEASURE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC}
};

static struct ima_rule_entry original_measurement_rules[] __ro_after_init = {
	{.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
	 .flags = IMA_FUNC | IMA_MASK},
	{.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
	 .flags = IMA_FUNC | IMA_MASK},
	{.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
	 .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
	 .flags = IMA_FUNC | IMA_MASK | IMA_UID},
	{.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
	{.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
};

static struct ima_rule_entry default_measurement_rules[] __ro_after_init = {
	{.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
	 .flags = IMA_FUNC | IMA_MASK},
	{.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
	 .flags = IMA_FUNC | IMA_MASK},
	{.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
	 .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
	 .flags = IMA_FUNC | IMA_INMASK | IMA_EUID},
	{.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
	 .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
	 .flags = IMA_FUNC | IMA_INMASK | IMA_UID},
	{.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
	{.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
	{.action = MEASURE, .func = POLICY_CHECK, .flags = IMA_FUNC},
};

static struct ima_rule_entry default_appraise_rules[] __ro_after_init = {
	{.action = DONT_APPRAISE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
	{.action = DONT_APPRAISE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
	{.action = DONT_APPRAISE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
	{.action = DONT_APPRAISE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
	{.action = DONT_APPRAISE, .fsmagic = RAMFS_MAGIC, .flags = IMA_FSMAGIC},
	{.action = DONT_APPRAISE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
	{.action = DONT_APPRAISE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
	{.action = DONT_APPRAISE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
	{.action = DONT_APPRAISE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
	{.action = DONT_APPRAISE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
	{.action = DONT_APPRAISE, .fsmagic = CGROUP_SUPER_MAGIC, .flags = IMA_FSMAGIC},
#ifdef CONFIG_IMA_WRITE_POLICY
	{.action = APPRAISE, .func = POLICY_CHECK,
	.flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
#endif
#ifndef CONFIG_IMA_APPRAISE_SIGNED_INIT
	{.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &uid_eq,
	 .flags = IMA_FOWNER},
#else
	/* force signature */
	{.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &uid_eq,
	 .flags = IMA_FOWNER | IMA_DIGSIG_REQUIRED},
#endif
};

static LIST_HEAD(ima_default_rules);
static LIST_HEAD(ima_policy_rules);
static LIST_HEAD(ima_temp_rules);
static struct list_head *ima_rules;

static int ima_policy __initdata;

static int __init default_measure_policy_setup(char *str)
{
	if (ima_policy)
		return 1;

	ima_policy = ORIGINAL_TCB;
	return 1;
}
__setup("ima_tcb", default_measure_policy_setup);

static int __init policy_setup(char *str)
{
	if (ima_policy)
		return 1;

	if (strcmp(str, "tcb") == 0)
		ima_policy = DEFAULT_TCB;

	return 1;
}
__setup("ima_policy=", policy_setup);

static bool ima_use_appraise_tcb __initdata;
static int __init default_appraise_policy_setup(char *str)
{
	ima_use_appraise_tcb = 1;
	return 1;
}
__setup("ima_appraise_tcb", default_appraise_policy_setup);

/*
 * The LSM policy can be reloaded, leaving the IMA LSM based rules referring
 * to the old, stale LSM policy.  Update the IMA LSM based rules to reflect
 * the reloaded LSM policy.  We assume the rules still exist; and BUG_ON() if
 * they don't.
 */
static void ima_lsm_update_rules(void)
{
	struct ima_rule_entry *entry;
	int result;
	int i;

	list_for_each_entry(entry, &ima_policy_rules, list) {
		for (i = 0; i < MAX_LSM_RULES; i++) {
			if (!entry->lsm[i].rule)
				continue;
			result = security_filter_rule_init(entry->lsm[i].type,
							   Audit_equal,
							   entry->lsm[i].args_p,
							   &entry->lsm[i].rule);
			BUG_ON(!entry->lsm[i].rule);
		}
	}
}

/**
 * ima_match_rules - determine whether an inode matches the measure rule.
 * @rule: a pointer to a rule
 * @inode: a pointer to an inode
 * @func: LIM hook identifier
 * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
 *
 * Returns true on rule match, false on failure.
 */
static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
			    enum ima_hooks func, int mask)
{
	struct task_struct *tsk = current;
	const struct cred *cred = current_cred();
	int i;

	if ((rule->flags & IMA_FUNC) &&
	    (rule->func != func && func != POST_SETATTR))
		return false;
	if ((rule->flags & IMA_MASK) &&
	    (rule->mask != mask && func != POST_SETATTR))
		return false;
	if ((rule->flags & IMA_INMASK) &&
	    (!(rule->mask & mask) && func != POST_SETATTR))
		return false;
	if ((rule->flags & IMA_FSMAGIC)
	    && rule->fsmagic != inode->i_sb->s_magic)
		return false;
	if ((rule->flags & IMA_FSUUID) &&
	    !uuid_equal(&rule->fsuuid, &inode->i_sb->s_uuid))
		return false;
	if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
		return false;
	if (rule->flags & IMA_EUID) {
		if (has_capability_noaudit(current, CAP_SETUID)) {
			if (!rule->uid_op(cred->euid, rule->uid)
			    && !rule->uid_op(cred->suid, rule->uid)
			    && !rule->uid_op(cred->uid, rule->uid))
				return false;
		} else if (!rule->uid_op(cred->euid, rule->uid))
			return false;
	}

	if ((rule->flags & IMA_FOWNER) &&
	    !rule->fowner_op(inode->i_uid, rule->fowner))
		return false;
	for (i = 0; i < MAX_LSM_RULES; i++) {
		int rc = 0;
		u32 osid, sid;
		int retried = 0;

		if (!rule->lsm[i].rule)
			continue;
retry:
		switch (i) {
		case LSM_OBJ_USER:
		case LSM_OBJ_ROLE:
		case LSM_OBJ_TYPE:
			security_inode_getsecid(inode, &osid);
			rc = security_filter_rule_match(osid,
							rule->lsm[i].type,
							Audit_equal,
							rule->lsm[i].rule,
							NULL);
			break;
		case LSM_SUBJ_USER:
		case LSM_SUBJ_ROLE:
		case LSM_SUBJ_TYPE:
			security_task_getsecid(tsk, &sid);
			rc = security_filter_rule_match(sid,
							rule->lsm[i].type,
							Audit_equal,
							rule->lsm[i].rule,
							NULL);
		default:
			break;
		}
		if ((rc < 0) && (!retried)) {
			retried = 1;
			ima_lsm_update_rules();
			goto retry;
		}
		if (!rc)
			return false;
	}
	return true;
}

/*
 * In addition to knowing that we need to appraise the file in general,
 * we need to differentiate between calling hooks, for hook specific rules.
 */
static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func)
{
	if (!(rule->flags & IMA_FUNC))
		return IMA_FILE_APPRAISE;

	switch (func) {
	case MMAP_CHECK:
		return IMA_MMAP_APPRAISE;
	case BPRM_CHECK:
		return IMA_BPRM_APPRAISE;
	case FILE_CHECK:
	case POST_SETATTR:
		return IMA_FILE_APPRAISE;
	case MODULE_CHECK ... MAX_CHECK - 1:
	default:
		return IMA_READ_APPRAISE;
	}
}

/**
 * ima_match_policy - decision based on LSM and other conditions
 * @inode: pointer to an inode for which the policy decision is being made
 * @func: IMA hook identifier
 * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
 * @pcr: set the pcr to extend
 *
 * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type)
 * conditions.
 *
 * Since the IMA policy may be updated multiple times we need to lock the
 * list when walking it.  Reads are many orders of magnitude more numerous
 * than writes so ima_match_policy() is classical RCU candidate.
 */
int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask,
		     int flags, int *pcr)
{
	struct ima_rule_entry *entry;
	int action = 0, actmask = flags | (flags << 1);

	rcu_read_lock();
	list_for_each_entry_rcu(entry, ima_rules, list) {

		if (!(entry->action & actmask))
			continue;

		if (!ima_match_rules(entry, inode, func, mask))
			continue;

		action |= entry->flags & IMA_ACTION_FLAGS;

		action |= entry->action & IMA_DO_MASK;
		if (entry->action & IMA_APPRAISE)
			action |= get_subaction(entry, func);

		if (entry->action & IMA_DO_MASK)
			actmask &= ~(entry->action | entry->action << 1);
		else
			actmask &= ~(entry->action | entry->action >> 1);

		if ((pcr) && (entry->flags & IMA_PCR))
			*pcr = entry->pcr;

		if (!actmask)
			break;
	}
	rcu_read_unlock();

	return action;
}

/*
 * Initialize the ima_policy_flag variable based on the currently
 * loaded policy.  Based on this flag, the decision to short circuit
 * out of a function or not call the function in the first place
 * can be made earlier.
 */
void ima_update_policy_flag(void)
{
	struct ima_rule_entry *entry;

	list_for_each_entry(entry, ima_rules, list) {
		if (entry->action & IMA_DO_MASK)
			ima_policy_flag |= entry->action;
	}

	ima_appraise |= temp_ima_appraise;
	if (!ima_appraise)
		ima_policy_flag &= ~IMA_APPRAISE;
}

/**
 * ima_init_policy - initialize the default measure rules.
 *
 * ima_rules points to either the ima_default_rules or the
 * the new ima_policy_rules.
 */
void __init ima_init_policy(void)
{
	int i, measure_entries, appraise_entries;

	/* if !ima_policy set entries = 0 so we load NO default rules */
	measure_entries = ima_policy ? ARRAY_SIZE(dont_measure_rules) : 0;
	appraise_entries = ima_use_appraise_tcb ?
			 ARRAY_SIZE(default_appraise_rules) : 0;

	for (i = 0; i < measure_entries; i++)
		list_add_tail(&dont_measure_rules[i].list, &ima_default_rules);

	switch (ima_policy) {
	case ORIGINAL_TCB:
		for (i = 0; i < ARRAY_SIZE(original_measurement_rules); i++)
			list_add_tail(&original_measurement_rules[i].list,
				      &ima_default_rules);
		break;
	case DEFAULT_TCB:
		for (i = 0; i < ARRAY_SIZE(default_measurement_rules); i++)
			list_add_tail(&default_measurement_rules[i].list,
				      &ima_default_rules);
	default:
		break;
	}

	for (i = 0; i < appraise_entries; i++) {
		list_add_tail(&default_appraise_rules[i].list,
			      &ima_default_rules);
		if (default_appraise_rules[i].func == POLICY_CHECK)
			temp_ima_appraise |= IMA_APPRAISE_POLICY;
	}

	ima_rules = &ima_default_rules;
	ima_update_policy_flag();
}

/* Make sure we have a valid policy, at least containing some rules. */
int ima_check_policy(void)
{
	if (list_empty(&ima_temp_rules))
		return -EINVAL;
	return 0;
}

/**
 * ima_update_policy - update default_rules with new measure rules
 *
 * Called on file .release to update the default rules with a complete new
 * policy.  What we do here is to splice ima_policy_rules and ima_temp_rules so
 * they make a queue.  The policy may be updated multiple times and this is the
 * RCU updater.
 *
 * Policy rules are never deleted so ima_policy_flag gets zeroed only once when
 * we switch from the default policy to user defined.
 */
void ima_update_policy(void)
{
	struct list_head *first, *last, *policy;

	/* append current policy with the new rules */
	first = (&ima_temp_rules)->next;
	last = (&ima_temp_rules)->prev;
	policy = &ima_policy_rules;

	synchronize_rcu();

	last->next = policy;
	rcu_assign_pointer(list_next_rcu(policy->prev), first);
	first->prev = policy->prev;
	policy->prev = last;

	/* prepare for the next policy rules addition */
	INIT_LIST_HEAD(&ima_temp_rules);

	if (ima_rules != policy) {
		ima_policy_flag = 0;
		ima_rules = policy;
	}
	ima_update_policy_flag();
}

enum {
	Opt_err = -1,
	Opt_measure = 1, Opt_dont_measure,
	Opt_appraise, Opt_dont_appraise,
	Opt_audit,
	Opt_obj_user, Opt_obj_role, Opt_obj_type,
	Opt_subj_user, Opt_subj_role, Opt_subj_type,
	Opt_func, Opt_mask, Opt_fsmagic,
	Opt_fsuuid, Opt_uid_eq, Opt_euid_eq, Opt_fowner_eq,
	Opt_uid_gt, Opt_euid_gt, Opt_fowner_gt,
	Opt_uid_lt, Opt_euid_lt, Opt_fowner_lt,
	Opt_appraise_type, Opt_permit_directio,
	Opt_pcr
};

static match_table_t policy_tokens = {
	{Opt_measure, "measure"},
	{Opt_dont_measure, "dont_measure"},
	{Opt_appraise, "appraise"},
	{Opt_dont_appraise, "dont_appraise"},
	{Opt_audit, "audit"},
	{Opt_obj_user, "obj_user=%s"},
	{Opt_obj_role, "obj_role=%s"},
	{Opt_obj_type, "obj_type=%s"},
	{Opt_subj_user, "subj_user=%s"},
	{Opt_subj_role, "subj_role=%s"},
	{Opt_subj_type, "subj_type=%s"},
	{Opt_func, "func=%s"},
	{Opt_mask, "mask=%s"},
	{Opt_fsmagic, "fsmagic=%s"},
	{Opt_fsuuid, "fsuuid=%s"},
	{Opt_uid_eq, "uid=%s"},
	{Opt_euid_eq, "euid=%s"},
	{Opt_fowner_eq, "fowner=%s"},
	{Opt_uid_gt, "uid>%s"},
	{Opt_euid_gt, "euid>%s"},
	{Opt_fowner_gt, "fowner>%s"},
	{Opt_uid_lt, "uid<%s"},
	{Opt_euid_lt, "euid<%s"},
	{Opt_fowner_lt, "fowner<%s"},
	{Opt_appraise_type, "appraise_type=%s"},
	{Opt_permit_directio, "permit_directio"},
	{Opt_pcr, "pcr=%s"},
	{Opt_err, NULL}
};

static int ima_lsm_rule_init(struct ima_rule_entry *entry,
			     substring_t *args, int lsm_rule, int audit_type)
{
	int result;

	if (entry->lsm[lsm_rule].rule)
		return -EINVAL;

	entry->lsm[lsm_rule].args_p = match_strdup(args);
	if (!entry->lsm[lsm_rule].args_p)
		return -ENOMEM;

	entry->lsm[lsm_rule].type = audit_type;
	result = security_filter_rule_init(entry->lsm[lsm_rule].type,
					   Audit_equal,
					   entry->lsm[lsm_rule].args_p,
					   &entry->lsm[lsm_rule].rule);
	if (!entry->lsm[lsm_rule].rule) {
		kfree(entry->lsm[lsm_rule].args_p);
		return -EINVAL;
	}

	return result;
}

static void ima_log_string_op(struct audit_buffer *ab, char *key, char *value,
			      bool (*rule_operator)(kuid_t, kuid_t))
{
	if (rule_operator == &uid_gt)
		audit_log_format(ab, "%s>", key);
	else if (rule_operator == &uid_lt)
		audit_log_format(ab, "%s<", key);
	else
		audit_log_format(ab, "%s=", key);
	audit_log_untrustedstring(ab, value);
	audit_log_format(ab, " ");
}
static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
{
	ima_log_string_op(ab, key, value, NULL);
}

static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
{
	struct audit_buffer *ab;
	char *from;
	char *p;
	bool uid_token;
	int result = 0;

	ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_RULE);

	entry->uid = INVALID_UID;
	entry->fowner = INVALID_UID;
	entry->uid_op = &uid_eq;
	entry->fowner_op = &uid_eq;
	entry->action = UNKNOWN;
	while ((p = strsep(&rule, " \t")) != NULL) {
		substring_t args[MAX_OPT_ARGS];
		int token;
		unsigned long lnum;

		if (result < 0)
			break;
		if ((*p == '\0') || (*p == ' ') || (*p == '\t'))
			continue;
		token = match_token(p, policy_tokens, args);
		switch (token) {
		case Opt_measure:
			ima_log_string(ab, "action", "measure");

			if (entry->action != UNKNOWN)
				result = -EINVAL;

			entry->action = MEASURE;
			break;
		case Opt_dont_measure:
			ima_log_string(ab, "action", "dont_measure");

			if (entry->action != UNKNOWN)
				result = -EINVAL;

			entry->action = DONT_MEASURE;
			break;
		case Opt_appraise:
			ima_log_string(ab, "action", "appraise");

			if (entry->action != UNKNOWN)
				result = -EINVAL;

			entry->action = APPRAISE;
			break;
		case Opt_dont_appraise:
			ima_log_string(ab, "action", "dont_appraise");

			if (entry->action != UNKNOWN)
				result = -EINVAL;

			entry->action = DONT_APPRAISE;
			break;
		case Opt_audit:
			ima_log_string(ab, "action", "audit");

			if (entry->action != UNKNOWN)
				result = -EINVAL;

			entry->action = AUDIT;
			break;
		case Opt_func:
			ima_log_string(ab, "func", args[0].from);

			if (entry->func)
				result = -EINVAL;

			if (strcmp(args[0].from, "FILE_CHECK") == 0)
				entry->func = FILE_CHECK;
			/* PATH_CHECK is for backwards compat */
			else if (strcmp(args[0].from, "PATH_CHECK") == 0)
				entry->func = FILE_CHECK;
			else if (strcmp(args[0].from, "MODULE_CHECK") == 0)
				entry->func = MODULE_CHECK;
			else if (strcmp(args[0].from, "FIRMWARE_CHECK") == 0)
				entry->func = FIRMWARE_CHECK;
			else if ((strcmp(args[0].from, "FILE_MMAP") == 0)
				|| (strcmp(args[0].from, "MMAP_CHECK") == 0))
				entry->func = MMAP_CHECK;
			else if (strcmp(args[0].from, "BPRM_CHECK") == 0)
				entry->func = BPRM_CHECK;
			else if (strcmp(args[0].from, "KEXEC_KERNEL_CHECK") ==
				 0)
				entry->func = KEXEC_KERNEL_CHECK;
			else if (strcmp(args[0].from, "KEXEC_INITRAMFS_CHECK")
				 == 0)
				entry->func = KEXEC_INITRAMFS_CHECK;
			else if (strcmp(args[0].from, "POLICY_CHECK") == 0)
				entry->func = POLICY_CHECK;
			else
				result = -EINVAL;
			if (!result)
				entry->flags |= IMA_FUNC;
			break;
		case Opt_mask:
			ima_log_string(ab, "mask", args[0].from);

			if (entry->mask)
				result = -EINVAL;

			from = args[0].from;
			if (*from == '^')
				from++;

			if ((strcmp(from, "MAY_EXEC")) == 0)
				entry->mask = MAY_EXEC;
			else if (strcmp(from, "MAY_WRITE") == 0)
				entry->mask = MAY_WRITE;
			else if (strcmp(from, "MAY_READ") == 0)
				entry->mask = MAY_READ;
			else if (strcmp(from, "MAY_APPEND") == 0)
				entry->mask = MAY_APPEND;
			else
				result = -EINVAL;
			if (!result)
				entry->flags |= (*args[0].from == '^')
				     ? IMA_INMASK : IMA_MASK;
			break;
		case Opt_fsmagic:
			ima_log_string(ab, "fsmagic", args[0].from);

			if (entry->fsmagic) {
				result = -EINVAL;
				break;
			}

			result = kstrtoul(args[0].from, 16, &entry->fsmagic);
			if (!result)
				entry->flags |= IMA_FSMAGIC;
			break;
		case Opt_fsuuid:
			ima_log_string(ab, "fsuuid", args[0].from);

			if (uuid_is_null(&entry->fsuuid)) {
				result = -EINVAL;
				break;
			}

			result = uuid_parse(args[0].from, &entry->fsuuid);
			if (!result)
				entry->flags |= IMA_FSUUID;
			break;
		case Opt_uid_gt:
		case Opt_euid_gt:
			entry->uid_op = &uid_gt;
		case Opt_uid_lt:
		case Opt_euid_lt:
			if ((token == Opt_uid_lt) || (token == Opt_euid_lt))
				entry->uid_op = &uid_lt;
		case Opt_uid_eq:
		case Opt_euid_eq:
			uid_token = (token == Opt_uid_eq) ||
				    (token == Opt_uid_gt) ||
				    (token == Opt_uid_lt);

			ima_log_string_op(ab, uid_token ? "uid" : "euid",
					  args[0].from, entry->uid_op);

			if (uid_valid(entry->uid)) {
				result = -EINVAL;
				break;
			}

			result = kstrtoul(args[0].from, 10, &lnum);
			if (!result) {
				entry->uid = make_kuid(current_user_ns(),
						       (uid_t) lnum);
				if (!uid_valid(entry->uid) ||
				    (uid_t)lnum != lnum)
					result = -EINVAL;
				else
					entry->flags |= uid_token
					    ? IMA_UID : IMA_EUID;
			}
			break;
		case Opt_fowner_gt:
			entry->fowner_op = &uid_gt;
		case Opt_fowner_lt:
			if (token == Opt_fowner_lt)
				entry->fowner_op = &uid_lt;
		case Opt_fowner_eq:
			ima_log_string_op(ab, "fowner", args[0].from,
					  entry->fowner_op);

			if (uid_valid(entry->fowner)) {
				result = -EINVAL;
				break;
			}

			result = kstrtoul(args[0].from, 10, &lnum);
			if (!result) {
				entry->fowner = make_kuid(current_user_ns(), (uid_t)lnum);
				if (!uid_valid(entry->fowner) || (((uid_t)lnum) != lnum))
					result = -EINVAL;
				else
					entry->flags |= IMA_FOWNER;
			}
			break;
		case Opt_obj_user:
			ima_log_string(ab, "obj_user", args[0].from);
			result = ima_lsm_rule_init(entry, args,
						   LSM_OBJ_USER,
						   AUDIT_OBJ_USER);
			break;
		case Opt_obj_role:
			ima_log_string(ab, "obj_role", args[0].from);
			result = ima_lsm_rule_init(entry, args,
						   LSM_OBJ_ROLE,
						   AUDIT_OBJ_ROLE);
			break;
		case Opt_obj_type:
			ima_log_string(ab, "obj_type", args[0].from);
			result = ima_lsm_rule_init(entry, args,
						   LSM_OBJ_TYPE,
						   AUDIT_OBJ_TYPE);
			break;
		case Opt_subj_user:
			ima_log_string(ab, "subj_user", args[0].from);
			result = ima_lsm_rule_init(entry, args,
						   LSM_SUBJ_USER,
						   AUDIT_SUBJ_USER);
			break;
		case Opt_subj_role:
			ima_log_string(ab, "subj_role", args[0].from);
			result = ima_lsm_rule_init(entry, args,
						   LSM_SUBJ_ROLE,
						   AUDIT_SUBJ_ROLE);
			break;
		case Opt_subj_type:
			ima_log_string(ab, "subj_type", args[0].from);
			result = ima_lsm_rule_init(entry, args,
						   LSM_SUBJ_TYPE,
						   AUDIT_SUBJ_TYPE);
			break;
		case Opt_appraise_type:
			if (entry->action != APPRAISE) {
				result = -EINVAL;
				break;
			}

			ima_log_string(ab, "appraise_type", args[0].from);
			if ((strcmp(args[0].from, "imasig")) == 0)
				entry->flags |= IMA_DIGSIG_REQUIRED;
			else
				result = -EINVAL;
			break;
		case Opt_permit_directio:
			entry->flags |= IMA_PERMIT_DIRECTIO;
			break;
		case Opt_pcr:
			if (entry->action != MEASURE) {
				result = -EINVAL;
				break;
			}
			ima_log_string(ab, "pcr", args[0].from);

			result = kstrtoint(args[0].from, 10, &entry->pcr);
			if (result || INVALID_PCR(entry->pcr))
				result = -EINVAL;
			else
				entry->flags |= IMA_PCR;

			break;
		case Opt_err:
			ima_log_string(ab, "UNKNOWN", p);
			result = -EINVAL;
			break;
		}
	}
	if (!result && (entry->action == UNKNOWN))
		result = -EINVAL;
	else if (entry->func == MODULE_CHECK)
		temp_ima_appraise |= IMA_APPRAISE_MODULES;
	else if (entry->func == FIRMWARE_CHECK)
		temp_ima_appraise |= IMA_APPRAISE_FIRMWARE;
	else if (entry->func == POLICY_CHECK)
		temp_ima_appraise |= IMA_APPRAISE_POLICY;
	audit_log_format(ab, "res=%d", !result);
	audit_log_end(ab);
	return result;
}

/**
 * ima_parse_add_rule - add a rule to ima_policy_rules
 * @rule - ima measurement policy rule
 *
 * Avoid locking by allowing just one writer at a time in ima_write_policy()
 * Returns the length of the rule parsed, an error code on failure
 */
ssize_t ima_parse_add_rule(char *rule)
{
	static const char op[] = "update_policy";
	char *p;
	struct ima_rule_entry *entry;
	ssize_t result, len;
	int audit_info = 0;

	p = strsep(&rule, "\n");
	len = strlen(p) + 1;
	p += strspn(p, " \t");

	if (*p == '#' || *p == '\0')
		return len;

	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
	if (!entry) {
		integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
				    NULL, op, "-ENOMEM", -ENOMEM, audit_info);
		return -ENOMEM;
	}

	INIT_LIST_HEAD(&entry->list);

	result = ima_parse_rule(p, entry);
	if (result) {
		kfree(entry);
		integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
				    NULL, op, "invalid-policy", result,
				    audit_info);
		return result;
	}

	list_add_tail(&entry->list, &ima_temp_rules);

	return len;
}

/**
 * ima_delete_rules() called to cleanup invalid in-flight policy.
 * We don't need locking as we operate on the temp list, which is
 * different from the active one.  There is also only one user of
 * ima_delete_rules() at a time.
 */
void ima_delete_rules(void)
{
	struct ima_rule_entry *entry, *tmp;
	int i;

	temp_ima_appraise = 0;
	list_for_each_entry_safe(entry, tmp, &ima_temp_rules, list) {
		for (i = 0; i < MAX_LSM_RULES; i++)
			kfree(entry->lsm[i].args_p);

		list_del(&entry->list);
		kfree(entry);
	}
}

#ifdef	CONFIG_IMA_READ_POLICY
enum {
	mask_exec = 0, mask_write, mask_read, mask_append
};

static char *mask_tokens[] = {
	"MAY_EXEC",
	"MAY_WRITE",
	"MAY_READ",
	"MAY_APPEND"
};

enum {
	func_file = 0, func_mmap, func_bprm,
	func_module, func_firmware, func_post,
	func_kexec_kernel, func_kexec_initramfs,
	func_policy
};

static char *func_tokens[] = {
	"FILE_CHECK",
	"MMAP_CHECK",
	"BPRM_CHECK",
	"MODULE_CHECK",
	"FIRMWARE_CHECK",
	"POST_SETATTR",
	"KEXEC_KERNEL_CHECK",
	"KEXEC_INITRAMFS_CHECK",
	"POLICY_CHECK"
};

void *ima_policy_start(struct seq_file *m, loff_t *pos)
{
	loff_t l = *pos;
	struct ima_rule_entry *entry;

	rcu_read_lock();
	list_for_each_entry_rcu(entry, ima_rules, list) {
		if (!l--) {
			rcu_read_unlock();
			return entry;
		}
	}
	rcu_read_unlock();
	return NULL;
}

void *ima_policy_next(struct seq_file *m, void *v, loff_t *pos)
{
	struct ima_rule_entry *entry = v;

	rcu_read_lock();
	entry = list_entry_rcu(entry->list.next, struct ima_rule_entry, list);
	rcu_read_unlock();
	(*pos)++;

	return (&entry->list == ima_rules) ? NULL : entry;
}

void ima_policy_stop(struct seq_file *m, void *v)
{
}

#define pt(token)	policy_tokens[token + Opt_err].pattern
#define mt(token)	mask_tokens[token]
#define ft(token)	func_tokens[token]

/*
 * policy_func_show - display the ima_hooks policy rule
 */
static void policy_func_show(struct seq_file *m, enum ima_hooks func)
{
	char tbuf[64] = {0,};

	switch (func) {
	case FILE_CHECK:
		seq_printf(m, pt(Opt_func), ft(func_file));
		break;
	case MMAP_CHECK:
		seq_printf(m, pt(Opt_func), ft(func_mmap));
		break;
	case BPRM_CHECK:
		seq_printf(m, pt(Opt_func), ft(func_bprm));
		break;
	case MODULE_CHECK:
		seq_printf(m, pt(Opt_func), ft(func_module));
		break;
	case FIRMWARE_CHECK:
		seq_printf(m, pt(Opt_func), ft(func_firmware));
		break;
	case POST_SETATTR:
		seq_printf(m, pt(Opt_func), ft(func_post));
		break;
	case KEXEC_KERNEL_CHECK:
		seq_printf(m, pt(Opt_func), ft(func_kexec_kernel));
		break;
	case KEXEC_INITRAMFS_CHECK:
		seq_printf(m, pt(Opt_func), ft(func_kexec_initramfs));
		break;
	case POLICY_CHECK:
		seq_printf(m, pt(Opt_func), ft(func_policy));
		break;
	default:
		snprintf(tbuf, sizeof(tbuf), "%d", func);
		seq_printf(m, pt(Opt_func), tbuf);
		break;
	}
	seq_puts(m, " ");
}

int ima_policy_show(struct seq_file *m, void *v)
{
	struct ima_rule_entry *entry = v;
	int i;
	char tbuf[64] = {0,};

	rcu_read_lock();

	if (entry->action & MEASURE)
		seq_puts(m, pt(Opt_measure));
	if (entry->action & DONT_MEASURE)
		seq_puts(m, pt(Opt_dont_measure));
	if (entry->action & APPRAISE)
		seq_puts(m, pt(Opt_appraise));
	if (entry->action & DONT_APPRAISE)
		seq_puts(m, pt(Opt_dont_appraise));
	if (entry->action & AUDIT)
		seq_puts(m, pt(Opt_audit));

	seq_puts(m, " ");

	if (entry->flags & IMA_FUNC)
		policy_func_show(m, entry->func);

	if (entry->flags & IMA_MASK) {
		if (entry->mask & MAY_EXEC)
			seq_printf(m, pt(Opt_mask), mt(mask_exec));
		if (entry->mask & MAY_WRITE)
			seq_printf(m, pt(Opt_mask), mt(mask_write));
		if (entry->mask & MAY_READ)
			seq_printf(m, pt(Opt_mask), mt(mask_read));
		if (entry->mask & MAY_APPEND)
			seq_printf(m, pt(Opt_mask), mt(mask_append));
		seq_puts(m, " ");
	}

	if (entry->flags & IMA_FSMAGIC) {
		snprintf(tbuf, sizeof(tbuf), "0x%lx", entry->fsmagic);
		seq_printf(m, pt(Opt_fsmagic), tbuf);
		seq_puts(m, " ");
	}

	if (entry->flags & IMA_PCR) {
		snprintf(tbuf, sizeof(tbuf), "%d", entry->pcr);
		seq_printf(m, pt(Opt_pcr), tbuf);
		seq_puts(m, " ");
	}

	if (entry->flags & IMA_FSUUID) {
		seq_printf(m, "fsuuid=%pU", &entry->fsuuid);
		seq_puts(m, " ");
	}

	if (entry->flags & IMA_UID) {
		snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
		if (entry->uid_op == &uid_gt)
			seq_printf(m, pt(Opt_uid_gt), tbuf);
		else if (entry->uid_op == &uid_lt)
			seq_printf(m, pt(Opt_uid_lt), tbuf);
		else
			seq_printf(m, pt(Opt_uid_eq), tbuf);
		seq_puts(m, " ");
	}

	if (entry->flags & IMA_EUID) {
		snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
		if (entry->uid_op == &uid_gt)
			seq_printf(m, pt(Opt_euid_gt), tbuf);
		else if (entry->uid_op == &uid_lt)
			seq_printf(m, pt(Opt_euid_lt), tbuf);
		else
			seq_printf(m, pt(Opt_euid_eq), tbuf);
		seq_puts(m, " ");
	}

	if (entry->flags & IMA_FOWNER) {
		snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->fowner));
		if (entry->fowner_op == &uid_gt)
			seq_printf(m, pt(Opt_fowner_gt), tbuf);
		else if (entry->fowner_op == &uid_lt)
			seq_printf(m, pt(Opt_fowner_lt), tbuf);
		else
			seq_printf(m, pt(Opt_fowner_eq), tbuf);
		seq_puts(m, " ");
	}

	for (i = 0; i < MAX_LSM_RULES; i++) {
		if (entry->lsm[i].rule) {
			switch (i) {
			case LSM_OBJ_USER:
				seq_printf(m, pt(Opt_obj_user),
					   (char *)entry->lsm[i].args_p);
				break;
			case LSM_OBJ_ROLE:
				seq_printf(m, pt(Opt_obj_role),
					   (char *)entry->lsm[i].args_p);
				break;
			case LSM_OBJ_TYPE:
				seq_printf(m, pt(Opt_obj_type),
					   (char *)entry->lsm[i].args_p);
				break;
			case LSM_SUBJ_USER:
				seq_printf(m, pt(Opt_subj_user),
					   (char *)entry->lsm[i].args_p);
				break;
			case LSM_SUBJ_ROLE:
				seq_printf(m, pt(Opt_subj_role),
					   (char *)entry->lsm[i].args_p);
				break;
			case LSM_SUBJ_TYPE:
				seq_printf(m, pt(Opt_subj_type),
					   (char *)entry->lsm[i].args_p);
				break;
			}
		}
	}
	if (entry->flags & IMA_DIGSIG_REQUIRED)
		seq_puts(m, "appraise_type=imasig ");
	if (entry->flags & IMA_PERMIT_DIRECTIO)
		seq_puts(m, "permit_directio ");
	rcu_read_unlock();
	seq_puts(m, "\n");
	return 0;
}
#endif	/* CONFIG_IMA_READ_POLICY */