summaryrefslogtreecommitdiff
path: root/security/apparmor/policy.c
blob: 41b8f275c626ca00a48f534423497d91d79a026c (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
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
/*
 * AppArmor security module
 *
 * This file contains AppArmor policy manipulation functions
 *
 * Copyright (C) 1998-2008 Novell/SUSE
 * Copyright 2009-2010 Canonical Ltd.
 *
 * 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.
 *
 *
 * AppArmor policy is based around profiles, which contain the rules a
 * task is confined by.  Every task in the system has a profile attached
 * to it determined either by matching "unconfined" tasks against the
 * visible set of profiles or by following a profiles attachment rules.
 *
 * Each profile exists in a profile namespace which is a container of
 * visible profiles.  Each namespace contains a special "unconfined" profile,
 * which doesn't enforce any confinement on a task beyond DAC.
 *
 * Namespace and profile names can be written together in either
 * of two syntaxes.
 *	:namespace:profile - used by kernel interfaces for easy detection
 *	namespace://profile - used by policy
 *
 * Profile names can not start with : or @ or ^ and may not contain \0
 *
 * Reserved profile names
 *	unconfined - special automatically generated unconfined profile
 *	inherit - special name to indicate profile inheritance
 *	null-XXXX-YYYY - special automatically generated learning profiles
 *
 * Namespace names may not start with / or @ and may not contain \0 or :
 * Reserved namespace names
 *	user-XXXX - user defined profiles
 *
 * a // in a profile or namespace name indicates a hierarchical name with the
 * name before the // being the parent and the name after the child.
 *
 * Profile and namespace hierarchies serve two different but similar purposes.
 * The namespace contains the set of visible profiles that are considered
 * for attachment.  The hierarchy of namespaces allows for virtualizing
 * the namespace so that for example a chroot can have its own set of profiles
 * which may define some local user namespaces.
 * The profile hierarchy severs two distinct purposes,
 * -  it allows for sub profiles or hats, which allows an application to run
 *    subprograms under its own profile with different restriction than it
 *    self, and not have it use the system profile.
 *    eg. if a mail program starts an editor, the policy might make the
 *        restrictions tighter on the editor tighter than the mail program,
 *        and definitely different than general editor restrictions
 * - it allows for binary hierarchy of profiles, so that execution history
 *   is preserved.  This feature isn't exploited by AppArmor reference policy
 *   but is allowed.  NOTE: this is currently suboptimal because profile
 *   aliasing is not currently implemented so that a profile for each
 *   level must be defined.
 *   eg. /bin/bash///bin/ls as a name would indicate /bin/ls was started
 *       from /bin/bash
 *
 *   A profile or namespace name that can contain one or more // separators
 *   is referred to as an hname (hierarchical).
 *   eg.  /bin/bash//bin/ls
 *
 *   An fqname is a name that may contain both namespace and profile hnames.
 *   eg. :ns:/bin/bash//bin/ls
 *
 * NOTES:
 *   - locking of profile lists is currently fairly coarse.  All profile
 *     lists within a namespace use the namespace lock.
 * FIXME: move profile lists to using rcu_lists
 */

#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/string.h>

#include "include/apparmor.h"
#include "include/capability.h"
#include "include/context.h"
#include "include/file.h"
#include "include/ipc.h"
#include "include/match.h"
#include "include/path.h"
#include "include/policy.h"
#include "include/policy_unpack.h"
#include "include/resource.h"


/* root profile namespace */
struct aa_namespace *root_ns;

const char *const profile_mode_names[] = {
	"enforce",
	"complain",
	"kill",
};

/**
 * hname_tail - find the last component of an hname
 * @name: hname to find the base profile name component of  (NOT NULL)
 *
 * Returns: the tail (base profile name) name component of an hname
 */
static const char *hname_tail(const char *hname)
{
	char *split;
	hname = strim((char *)hname);
	for (split = strstr(hname, "//"); split; split = strstr(hname, "//"))
		hname = split + 2;

	return hname;
}

/**
 * policy_init - initialize a policy structure
 * @policy: policy to initialize  (NOT NULL)
 * @prefix: prefix name if any is required.  (MAYBE NULL)
 * @name: name of the policy, init will make a copy of it  (NOT NULL)
 *
 * Note: this fn creates a copy of strings passed in
 *
 * Returns: true if policy init successful
 */
static bool policy_init(struct aa_policy *policy, const char *prefix,
			const char *name)
{
	/* freed by policy_free */
	if (prefix) {
		policy->hname = kmalloc(strlen(prefix) + strlen(name) + 3,
					GFP_KERNEL);
		if (policy->hname)
			sprintf(policy->hname, "%s//%s", prefix, name);
	} else
		policy->hname = kstrdup(name, GFP_KERNEL);
	if (!policy->hname)
		return 0;
	/* base.name is a substring of fqname */
	policy->name = (char *)hname_tail(policy->hname);
	INIT_LIST_HEAD(&policy->list);
	INIT_LIST_HEAD(&policy->profiles);
	kref_init(&policy->count);

	return 1;
}

/**
 * policy_destroy - free the elements referenced by @policy
 * @policy: policy that is to have its elements freed  (NOT NULL)
 */
static void policy_destroy(struct aa_policy *policy)
{
	/* still contains profiles -- invalid */
	if (on_list_rcu(&policy->profiles)) {
		AA_ERROR("%s: internal error, "
			 "policy '%s' still contains profiles\n",
			 __func__, policy->name);
		BUG();
	}
	if (on_list_rcu(&policy->list)) {
		AA_ERROR("%s: internal error, policy '%s' still on list\n",
			 __func__, policy->name);
		BUG();
	}

	/* don't free name as its a subset of hname */
	kzfree(policy->hname);
}

/**
 * __policy_find - find a policy by @name on a policy list
 * @head: list to search  (NOT NULL)
 * @name: name to search for  (NOT NULL)
 *
 * Requires: rcu_read_lock be held
 *
 * Returns: unrefcounted policy that match @name or NULL if not found
 */
static struct aa_policy *__policy_find(struct list_head *head, const char *name)
{
	struct aa_policy *policy;

	list_for_each_entry_rcu(policy, head, list) {
		if (!strcmp(policy->name, name))
			return policy;
	}
	return NULL;
}

/**
 * __policy_strn_find - find a policy that's name matches @len chars of @str
 * @head: list to search  (NOT NULL)
 * @str: string to search for  (NOT NULL)
 * @len: length of match required
 *
 * Requires: rcu_read_lock be held
 *
 * Returns: unrefcounted policy that match @str or NULL if not found
 *
 * if @len == strlen(@strlen) then this is equiv to __policy_find
 * other wise it allows searching for policy by a partial match of name
 */
static struct aa_policy *__policy_strn_find(struct list_head *head,
					    const char *str, int len)
{
	struct aa_policy *policy;

	list_for_each_entry_rcu(policy, head, list) {
		if (aa_strneq(policy->name, str, len))
			return policy;
	}

	return NULL;
}

/*
 * Routines for AppArmor namespaces
 */

static const char *hidden_ns_name = "---";
/**
 * aa_ns_visible - test if @view is visible from @curr
 * @curr: namespace to treat as the parent (NOT NULL)
 * @view:  namespace to test if visible from @curr (NOT NULL)
 *
 * Returns: true if @view is visible from @curr else false
 */
bool aa_ns_visible(struct aa_namespace *curr, struct aa_namespace *view)
{
	if (curr == view)
		return true;

	for ( ; view; view = view->parent) {
		if (view->parent == curr)
			return true;
	}
	return false;
}

/**
 * aa_na_name - Find the ns name to display for @view from @curr
 * @curr - current namespace (NOT NULL)
 * @view - namespace attempting to view (NOT NULL)
 *
 * Returns: name of @view visible from @curr
 */
const char *aa_ns_name(struct aa_namespace *curr, struct aa_namespace *view)
{
	/* if view == curr then the namespace name isn't displayed */
	if (curr == view)
		return "";

	if (aa_ns_visible(curr, view)) {
		/* at this point if a ns is visible it is in a view ns
		 * thus the curr ns.hname is a prefix of its name.
		 * Only output the virtualized portion of the name
		 * Add + 2 to skip over // separating curr hname prefix
		 * from the visible tail of the views hname
		 */
		return view->base.hname + strlen(curr->base.hname) + 2;
	} else
		return hidden_ns_name;
}

/**
 * alloc_namespace - allocate, initialize and return a new namespace
 * @prefix: parent namespace name (MAYBE NULL)
 * @name: a preallocated name  (NOT NULL)
 *
 * Returns: refcounted namespace or NULL on failure.
 */
static struct aa_namespace *alloc_namespace(const char *prefix,
					    const char *name)
{
	struct aa_namespace *ns;

	ns = kzalloc(sizeof(*ns), GFP_KERNEL);
	AA_DEBUG("%s(%p)\n", __func__, ns);
	if (!ns)
		return NULL;
	if (!policy_init(&ns->base, prefix, name))
		goto fail_ns;

	INIT_LIST_HEAD(&ns->sub_ns);
	mutex_init(&ns->lock);

	/* released by free_namespace */
	ns->unconfined = aa_alloc_profile("unconfined");
	if (!ns->unconfined)
		goto fail_unconfined;

	ns->unconfined->flags = PFLAG_UNCONFINED | PFLAG_IX_ON_NAME_ERROR |
	    PFLAG_IMMUTABLE;

	/*
	 * released by free_namespace, however __remove_namespace breaks
	 * the cyclic references (ns->unconfined, and unconfined->ns) and
	 * replaces with refs to parent namespace unconfined
	 */
	ns->unconfined->ns = aa_get_namespace(ns);

	atomic_set(&ns->uniq_null, 0);

	return ns;

fail_unconfined:
	kzfree(ns->base.hname);
fail_ns:
	kzfree(ns);
	return NULL;
}

/**
 * free_namespace - free a profile namespace
 * @ns: the namespace to free  (MAYBE NULL)
 *
 * Requires: All references to the namespace must have been put, if the
 *           namespace was referenced by a profile confining a task,
 */
static void free_namespace(struct aa_namespace *ns)
{
	if (!ns)
		return;

	policy_destroy(&ns->base);
	aa_put_namespace(ns->parent);

	if (ns->unconfined && ns->unconfined->ns == ns)
		ns->unconfined->ns = NULL;

	aa_put_profile(ns->unconfined);
	kzfree(ns);
}

/**
 * aa_free_namespace_kref - free aa_namespace by kref (see aa_put_namespace)
 * @kr: kref callback for freeing of a namespace  (NOT NULL)
 */
void aa_free_namespace_kref(struct kref *kref)
{
	free_namespace(container_of(kref, struct aa_namespace, base.count));
}

/**
 * __aa_find_namespace - find a namespace on a list by @name
 * @head: list to search for namespace on  (NOT NULL)
 * @name: name of namespace to look for  (NOT NULL)
 *
 * Returns: unrefcounted namespace
 *
 * Requires: rcu_read_lock be held
 */
static struct aa_namespace *__aa_find_namespace(struct list_head *head,
						const char *name)
{
	return (struct aa_namespace *)__policy_find(head, name);
}

/**
 * aa_find_namespace  -  look up a profile namespace on the namespace list
 * @root: namespace to search in  (NOT NULL)
 * @name: name of namespace to find  (NOT NULL)
 *
 * Returns: a refcounted namespace on the list, or NULL if no namespace
 *          called @name exists.
 *
 * refcount released by caller
 */
struct aa_namespace *aa_find_namespace(struct aa_namespace *root,
				       const char *name)
{
	struct aa_namespace *ns = NULL;

	rcu_read_lock();
	ns = aa_get_namespace(__aa_find_namespace(&root->sub_ns, name));
	rcu_read_unlock();

	return ns;
}

/**
 * aa_prepare_namespace - find an existing or create a new namespace of @name
 * @name: the namespace to find or add  (MAYBE NULL)
 *
 * Returns: refcounted namespace or NULL if failed to create one
 */
static struct aa_namespace *aa_prepare_namespace(const char *name)
{
	struct aa_namespace *ns, *root;

	root = aa_current_profile()->ns;

	mutex_lock(&root->lock);

	/* if name isn't specified the profile is loaded to the current ns */
	if (!name) {
		/* released by caller */
		ns = aa_get_namespace(root);
		goto out;
	}

	/* try and find the specified ns and if it doesn't exist create it */
	/* released by caller */
	ns = aa_get_namespace(__aa_find_namespace(&root->sub_ns, name));
	if (!ns) {
		ns = alloc_namespace(root->base.hname, name);
		if (!ns)
			goto out;
		/* add parent ref */
		ns->parent = aa_get_namespace(root);
		list_add_rcu(&ns->base.list, &root->sub_ns);
		/* add list ref */
		aa_get_namespace(ns);
	}
out:
	mutex_unlock(&root->lock);

	/* return ref */
	return ns;
}

/**
 * __list_add_profile - add a profile to a list
 * @list: list to add it to  (NOT NULL)
 * @profile: the profile to add  (NOT NULL)
 *
 * refcount @profile, should be put by __list_remove_profile
 *
 * Requires: namespace lock be held, or list not be shared
 */
static void __list_add_profile(struct list_head *list,
			       struct aa_profile *profile)
{
	list_add_rcu(&profile->base.list, list);
	/* get list reference */
	aa_get_profile(profile);
}

/**
 * __list_remove_profile - remove a profile from the list it is on
 * @profile: the profile to remove  (NOT NULL)
 *
 * remove a profile from the list, warning generally removal should
 * be done with __replace_profile as most profile removals are
 * replacements to the unconfined profile.
 *
 * put @profile list refcount
 *
 * Requires: namespace lock be held, or list not have been live
 */
static void __list_remove_profile(struct aa_profile *profile)
{
	list_del_rcu(&profile->base.list);
	aa_put_profile(profile);
}

static void __profile_list_release(struct list_head *head);

/**
 * __remove_profile - remove old profile, and children
 * @profile: profile to be replaced  (NOT NULL)
 *
 * Requires: namespace list lock be held, or list not be shared
 */
static void __remove_profile(struct aa_profile *profile)
{
	/* release any children lists first */
	__profile_list_release(&profile->base.profiles);
	/* released by free_profile */
	__aa_update_replacedby(profile, profile->ns->unconfined);
	__list_remove_profile(profile);
}

/**
 * __profile_list_release - remove all profiles on the list and put refs
 * @head: list of profiles  (NOT NULL)
 *
 * Requires: namespace lock be held
 */
static void __profile_list_release(struct list_head *head)
{
	struct aa_profile *profile, *tmp;
	list_for_each_entry_safe(profile, tmp, head, base.list)
		__remove_profile(profile);
}

static void __ns_list_release(struct list_head *head);

/**
 * destroy_namespace - remove everything contained by @ns
 * @ns: namespace to have it contents removed  (NOT NULL)
 */
static void destroy_namespace(struct aa_namespace *ns)
{
	struct aa_profile *unconfined;

	if (!ns)
		return;

	mutex_lock(&ns->lock);
	/* release all profiles in this namespace */
	__profile_list_release(&ns->base.profiles);

	/* release all sub namespaces */
	__ns_list_release(&ns->sub_ns);

	unconfined = ns->unconfined;
	/*
	 * break the ns, unconfined profile cyclic reference and forward
	 * all new unconfined profiles requests to the parent namespace
	 * This will result in all confined tasks that have a profile
	 * being removed, inheriting the parent->unconfined profile.
	 */
	if (ns->parent)
		ns->unconfined = aa_get_profile(ns->parent->unconfined);

	/* release original ns->unconfined ref */
	aa_put_profile(unconfined);

	mutex_unlock(&ns->lock);
}

static void aa_put_ns_rcu(struct rcu_head *head)
{
	struct aa_namespace *ns = container_of(head, struct aa_namespace,
					       base.rcu);
	/* release ns->base.list ref */
	aa_put_namespace(ns);
}

/**
 * __remove_namespace - remove a namespace and all its children
 * @ns: namespace to be removed  (NOT NULL)
 *
 * Requires: ns->parent->lock be held and ns removed from parent.
 */
static void __remove_namespace(struct aa_namespace *ns)
{
	/* remove ns from namespace list */
	list_del_rcu(&ns->base.list);

	destroy_namespace(ns);

	call_rcu(&ns->base.rcu, aa_put_ns_rcu);
}

/**
 * __ns_list_release - remove all profile namespaces on the list put refs
 * @head: list of profile namespaces  (NOT NULL)
 *
 * Requires: namespace lock be held
 */
static void __ns_list_release(struct list_head *head)
{
	struct aa_namespace *ns, *tmp;
	list_for_each_entry_safe(ns, tmp, head, base.list)
		__remove_namespace(ns);

}

/**
 * aa_alloc_root_ns - allocate the root profile namespace
 *
 * Returns: %0 on success else error
 *
 */
int __init aa_alloc_root_ns(void)
{
	/* released by aa_free_root_ns - used as list ref*/
	root_ns = alloc_namespace(NULL, "root");
	if (!root_ns)
		return -ENOMEM;

	return 0;
}

 /**
  * aa_free_root_ns - free the root profile namespace
  */
void __init aa_free_root_ns(void)
 {
	 struct aa_namespace *ns = root_ns;
	 root_ns = NULL;

	 destroy_namespace(ns);
	 aa_put_namespace(ns);
}


static void free_replacedby(struct aa_replacedby *r)
{
	if (r) {
		aa_put_profile(rcu_dereference(r->profile));
		kzfree(r);
	}
}


void aa_free_replacedby_kref(struct kref *kref)
{
	struct aa_replacedby *r = container_of(kref, struct aa_replacedby,
					       count);
	free_replacedby(r);
}

/**
 * free_profile - free a profile
 * @profile: the profile to free  (MAYBE NULL)
 *
 * Free a profile, its hats and null_profile. All references to the profile,
 * its hats and null_profile must have been put.
 *
 * If the profile was referenced from a task context, free_profile() will
 * be called from an rcu callback routine, so we must not sleep here.
 */
static void free_profile(struct aa_profile *profile)
{
	AA_DEBUG("%s(%p)\n", __func__, profile);

	if (!profile)
		return;

	/* free children profiles */
	policy_destroy(&profile->base);
	aa_put_profile(rcu_access_pointer(profile->parent));

	aa_put_namespace(profile->ns);
	kzfree(profile->rename);

	aa_free_file_rules(&profile->file);
	aa_free_cap_rules(&profile->caps);
	aa_free_rlimit_rules(&profile->rlimits);

	aa_put_dfa(profile->xmatch);
	aa_put_dfa(profile->policy.dfa);
	aa_put_replacedby(profile->replacedby);

	kzfree(profile);
}

/**
 * aa_free_profile_rcu - free aa_profile by rcu (called by aa_free_profile_kref)
 * @head: rcu_head callback for freeing of a profile  (NOT NULL)
 */
static void aa_free_profile_rcu(struct rcu_head *head)
{
	struct aa_profile *p = container_of(head, struct aa_profile, base.rcu);
	free_profile(p);
}

/**
 * aa_free_profile_kref - free aa_profile by kref (called by aa_put_profile)
 * @kr: kref callback for freeing of a profile  (NOT NULL)
 */
void aa_free_profile_kref(struct kref *kref)
{
	struct aa_profile *p = container_of(kref, struct aa_profile,
					    base.count);
	call_rcu(&p->base.rcu, aa_free_profile_rcu);
}

/**
 * aa_alloc_profile - allocate, initialize and return a new profile
 * @hname: name of the profile  (NOT NULL)
 *
 * Returns: refcount profile or NULL on failure
 */
struct aa_profile *aa_alloc_profile(const char *hname)
{
	struct aa_profile *profile;

	/* freed by free_profile - usually through aa_put_profile */
	profile = kzalloc(sizeof(*profile), GFP_KERNEL);
	if (!profile)
		return NULL;

	profile->replacedby = kzalloc(sizeof(struct aa_replacedby), GFP_KERNEL);
	if (!profile->replacedby)
		goto fail;
	kref_init(&profile->replacedby->count);

	if (!policy_init(&profile->base, NULL, hname))
		goto fail;

	/* refcount released by caller */
	return profile;

fail:
	kzfree(profile->replacedby);
	kzfree(profile);

	return NULL;
}

/**
 * aa_new_null_profile - create a new null-X learning profile
 * @parent: profile that caused this profile to be created (NOT NULL)
 * @hat: true if the null- learning profile is a hat
 *
 * Create a null- complain mode profile used in learning mode.  The name of
 * the profile is unique and follows the format of parent//null-<uniq>.
 *
 * null profiles are added to the profile list but the list does not
 * hold a count on them so that they are automatically released when
 * not in use.
 *
 * Returns: new refcounted profile else NULL on failure
 */
struct aa_profile *aa_new_null_profile(struct aa_profile *parent, int hat)
{
	struct aa_profile *profile = NULL;
	char *name;
	int uniq = atomic_inc_return(&parent->ns->uniq_null);

	/* freed below */
	name = kmalloc(strlen(parent->base.hname) + 2 + 7 + 8, GFP_KERNEL);
	if (!name)
		goto fail;
	sprintf(name, "%s//null-%x", parent->base.hname, uniq);

	profile = aa_alloc_profile(name);
	kfree(name);
	if (!profile)
		goto fail;

	profile->mode = APPARMOR_COMPLAIN;
	profile->flags = PFLAG_NULL;
	if (hat)
		profile->flags |= PFLAG_HAT;

	/* released on free_profile */
	rcu_assign_pointer(profile->parent, aa_get_profile(parent));
	profile->ns = aa_get_namespace(parent->ns);

	mutex_lock(&profile->ns->lock);
	__list_add_profile(&parent->base.profiles, profile);
	mutex_unlock(&profile->ns->lock);

	/* refcount released by caller */
	return profile;

fail:
	return NULL;
}

/* TODO: profile accounting - setup in remove */

/**
 * __find_child - find a profile on @head list with a name matching @name
 * @head: list to search  (NOT NULL)
 * @name: name of profile (NOT NULL)
 *
 * Requires: rcu_read_lock be held
 *
 * Returns: unrefcounted profile ptr, or NULL if not found
 */
static struct aa_profile *__find_child(struct list_head *head, const char *name)
{
	return (struct aa_profile *)__policy_find(head, name);
}

/**
 * __strn_find_child - find a profile on @head list using substring of @name
 * @head: list to search  (NOT NULL)
 * @name: name of profile (NOT NULL)
 * @len: length of @name substring to match
 *
 * Requires: rcu_read_lock be held
 *
 * Returns: unrefcounted profile ptr, or NULL if not found
 */
static struct aa_profile *__strn_find_child(struct list_head *head,
					    const char *name, int len)
{
	return (struct aa_profile *)__policy_strn_find(head, name, len);
}

/**
 * aa_find_child - find a profile by @name in @parent
 * @parent: profile to search  (NOT NULL)
 * @name: profile name to search for  (NOT NULL)
 *
 * Returns: a refcounted profile or NULL if not found
 */
struct aa_profile *aa_find_child(struct aa_profile *parent, const char *name)
{
	struct aa_profile *profile;

	rcu_read_lock();
	profile = aa_get_profile(__find_child(&parent->base.profiles, name));
	rcu_read_unlock();

	/* refcount released by caller */
	return profile;
}

/**
 * __lookup_parent - lookup the parent of a profile of name @hname
 * @ns: namespace to lookup profile in  (NOT NULL)
 * @hname: hierarchical profile name to find parent of  (NOT NULL)
 *
 * Lookups up the parent of a fully qualified profile name, the profile
 * that matches hname does not need to exist, in general this
 * is used to load a new profile.
 *
 * Requires: rcu_read_lock be held
 *
 * Returns: unrefcounted policy or NULL if not found
 */
static struct aa_policy *__lookup_parent(struct aa_namespace *ns,
					 const char *hname)
{
	struct aa_policy *policy;
	struct aa_profile *profile = NULL;
	char *split;

	policy = &ns->base;

	for (split = strstr(hname, "//"); split;) {
		profile = __strn_find_child(&policy->profiles, hname,
					    split - hname);
		if (!profile)
			return NULL;
		policy = &profile->base;
		hname = split + 2;
		split = strstr(hname, "//");
	}
	if (!profile)
		return &ns->base;
	return &profile->base;
}

/**
 * __lookup_profile - lookup the profile matching @hname
 * @base: base list to start looking up profile name from  (NOT NULL)
 * @hname: hierarchical profile name  (NOT NULL)
 *
 * Requires: rcu_read_lock be held
 *
 * Returns: unrefcounted profile pointer or NULL if not found
 *
 * Do a relative name lookup, recursing through profile tree.
 */
static struct aa_profile *__lookup_profile(struct aa_policy *base,
					   const char *hname)
{
	struct aa_profile *profile = NULL;
	char *split;

	for (split = strstr(hname, "//"); split;) {
		profile = __strn_find_child(&base->profiles, hname,
					    split - hname);
		if (!profile)
			return NULL;

		base = &profile->base;
		hname = split + 2;
		split = strstr(hname, "//");
	}

	profile = __find_child(&base->profiles, hname);

	return profile;
}

/**
 * aa_lookup_profile - find a profile by its full or partial name
 * @ns: the namespace to start from (NOT NULL)
 * @hname: name to do lookup on.  Does not contain namespace prefix (NOT NULL)
 *
 * Returns: refcounted profile or NULL if not found
 */
struct aa_profile *aa_lookup_profile(struct aa_namespace *ns, const char *hname)
{
	struct aa_profile *profile;

	rcu_read_lock();
	do {
		profile = __lookup_profile(&ns->base, hname);
	} while (profile && !aa_get_profile_not0(profile));
	rcu_read_unlock();

	/* the unconfined profile is not in the regular profile list */
	if (!profile && strcmp(hname, "unconfined") == 0)
		profile = aa_get_profile(ns->unconfined);

	/* refcount released by caller */
	return profile;
}

/**
 * replacement_allowed - test to see if replacement is allowed
 * @profile: profile to test if it can be replaced  (MAYBE NULL)
 * @noreplace: true if replacement shouldn't be allowed but addition is okay
 * @info: Returns - info about why replacement failed (NOT NULL)
 *
 * Returns: %0 if replacement allowed else error code
 */
static int replacement_allowed(struct aa_profile *profile, int noreplace,
			       const char **info)
{
	if (profile) {
		if (profile->flags & PFLAG_IMMUTABLE) {
			*info = "cannot replace immutible profile";
			return -EPERM;
		} else if (noreplace) {
			*info = "profile already exists";
			return -EEXIST;
		}
	}
	return 0;
}

/**
 * aa_audit_policy - Do auditing of policy changes
 * @op: policy operation being performed
 * @gfp: memory allocation flags
 * @name: name of profile being manipulated (NOT NULL)
 * @info: any extra information to be audited (MAYBE NULL)
 * @error: error code
 *
 * Returns: the error to be returned after audit is done
 */
static int audit_policy(int op, gfp_t gfp, const char *name, const char *info,
			int error)
{
	struct common_audit_data sa;
	struct apparmor_audit_data aad = {0,};
	sa.type = LSM_AUDIT_DATA_NONE;
	sa.aad = &aad;
	aad.op = op;
	aad.name = name;
	aad.info = info;
	aad.error = error;

	return aa_audit(AUDIT_APPARMOR_STATUS, __aa_current_profile(), gfp,
			&sa, NULL);
}

/**
 * aa_may_manage_policy - can the current task manage policy
 * @op: the policy manipulation operation being done
 *
 * Returns: true if the task is allowed to manipulate policy
 */
bool aa_may_manage_policy(int op)
{
	/* check if loading policy is locked out */
	if (aa_g_lock_policy) {
		audit_policy(op, GFP_KERNEL, NULL, "policy_locked", -EACCES);
		return 0;
	}

	if (!capable(CAP_MAC_ADMIN)) {
		audit_policy(op, GFP_KERNEL, NULL, "not policy admin", -EACCES);
		return 0;
	}

	return 1;
}

static struct aa_profile *__list_lookup_parent(struct list_head *lh,
					       struct aa_profile *profile)
{
	const char *base = hname_tail(profile->base.hname);
	long len = base - profile->base.hname;
	struct aa_load_ent *ent;

	/* parent won't have trailing // so remove from len */
	if (len <= 2)
		return NULL;
	len -= 2;

	list_for_each_entry(ent, lh, list) {
		if (ent->new == profile)
			continue;
		if (strncmp(ent->new->base.hname, profile->base.hname, len) ==
		    0 && ent->new->base.hname[len] == 0)
			return ent->new;
	}

	return NULL;
}

/**
 * __replace_profile - replace @old with @new on a list
 * @old: profile to be replaced  (NOT NULL)
 * @new: profile to replace @old with  (NOT NULL)
 * @share_replacedby: transfer @old->replacedby to @new
 *
 * Will duplicate and refcount elements that @new inherits from @old
 * and will inherit @old children.
 *
 * refcount @new for list, put @old list refcount
 *
 * Requires: namespace list lock be held, or list not be shared
 */
static void __replace_profile(struct aa_profile *old, struct aa_profile *new,
			      bool share_replacedby)
{
	struct aa_profile *child, *tmp;

	if (!list_empty(&old->base.profiles)) {
		LIST_HEAD(lh);
		list_splice_init_rcu(&old->base.profiles, &lh, synchronize_rcu);

		list_for_each_entry_safe(child, tmp, &lh, base.list) {
			struct aa_profile *p;

			list_del_init(&child->base.list);
			p = __find_child(&new->base.profiles, child->base.name);
			if (p) {
				/* @p replaces @child  */
				__replace_profile(child, p, share_replacedby);
				continue;
			}

			/* inherit @child and its children */
			/* TODO: update hname of inherited children */
			/* list refcount transferred to @new */
			p = rcu_dereference_protected(child->parent,
					     mutex_is_locked(&child->ns->lock));
			rcu_assign_pointer(child->parent, aa_get_profile(new));
			list_add_rcu(&child->base.list, &new->base.profiles);
			aa_put_profile(p);
		}
	}

	if (!rcu_access_pointer(new->parent)) {
		struct aa_profile *parent = rcu_dereference(old->parent);
		rcu_assign_pointer(new->parent, aa_get_profile(parent));
	}
	__aa_update_replacedby(old, new);
	if (share_replacedby) {
		aa_put_replacedby(new->replacedby);
		new->replacedby = aa_get_replacedby(old->replacedby);
	}

	if (list_empty(&new->base.list)) {
		/* new is not on a list already */
		list_replace_rcu(&old->base.list, &new->base.list);
		aa_get_profile(new);
		aa_put_profile(old);
	} else
		__list_remove_profile(old);
}

/**
 * __lookup_replace - lookup replacement information for a profile
 * @ns - namespace the lookup occurs in
 * @hname - name of profile to lookup
 * @noreplace - true if not replacing an existing profile
 * @p - Returns: profile to be replaced
 * @info - Returns: info string on why lookup failed
 *
 * Returns: profile to replace (no ref) on success else ptr error
 */
static int __lookup_replace(struct aa_namespace *ns, const char *hname,
			    bool noreplace, struct aa_profile **p,
			    const char **info)
{
	*p = aa_get_profile(__lookup_profile(&ns->base, hname));
	if (*p) {
		int error = replacement_allowed(*p, noreplace, info);
		if (error) {
			*info = "profile can not be replaced";
			return error;
		}
	}

	return 0;
}

/**
 * aa_replace_profiles - replace profile(s) on the profile list
 * @udata: serialized data stream  (NOT NULL)
 * @size: size of the serialized data stream
 * @noreplace: true if only doing addition, no replacement allowed
 *
 * unpack and replace a profile on the profile list and uses of that profile
 * by any aa_task_cxt.  If the profile does not exist on the profile list
 * it is added.
 *
 * Returns: size of data consumed else error code on failure.
 */
ssize_t aa_replace_profiles(void *udata, size_t size, bool noreplace)
{
	const char *ns_name, *name = NULL, *info = NULL;
	struct aa_namespace *ns = NULL;
	struct aa_load_ent *ent, *tmp;
	int op = OP_PROF_REPL;
	ssize_t error;
	LIST_HEAD(lh);

	/* released below */
	error = aa_unpack(udata, size, &lh, &ns_name);
	if (error)
		goto out;

	/* released below */
	ns = aa_prepare_namespace(ns_name);
	if (!ns) {
		info = "failed to prepare namespace";
		error = -ENOMEM;
		name = ns_name;
		goto fail;
	}

	mutex_lock(&ns->lock);
	/* setup parent and ns info */
	list_for_each_entry(ent, &lh, list) {
		struct aa_policy *policy;

		name = ent->new->base.hname;
		error = __lookup_replace(ns, ent->new->base.hname, noreplace,
					 &ent->old, &info);
		if (error)
			goto fail_lock;

		if (ent->new->rename) {
			error = __lookup_replace(ns, ent->new->rename,
						 noreplace, &ent->rename,
						 &info);
			if (error)
				goto fail_lock;
		}

		/* released when @new is freed */
		ent->new->ns = aa_get_namespace(ns);

		if (ent->old || ent->rename)
			continue;

		/* no ref on policy only use inside lock */
		policy = __lookup_parent(ns, ent->new->base.hname);
		if (!policy) {
			struct aa_profile *p;
			p = __list_lookup_parent(&lh, ent->new);
			if (!p) {
				error = -ENOENT;
				info = "parent does not exist";
				name = ent->new->base.hname;
				goto fail_lock;
			}
			rcu_assign_pointer(ent->new->parent, aa_get_profile(p));
		} else if (policy != &ns->base) {
			/* released on profile replacement or free_profile */
			struct aa_profile *p = (struct aa_profile *) policy;
			rcu_assign_pointer(ent->new->parent, aa_get_profile(p));
		}
	}

	/* do actual replacement */
	list_for_each_entry_safe(ent, tmp, &lh, list) {
		list_del_init(&ent->list);
		op = (!ent->old && !ent->rename) ? OP_PROF_LOAD : OP_PROF_REPL;

		audit_policy(op, GFP_ATOMIC, ent->new->base.name, NULL, error);

		if (ent->old) {
			__replace_profile(ent->old, ent->new, 1);
			if (ent->rename)
				__replace_profile(ent->rename, ent->new, 0);
		} else if (ent->rename) {
			__replace_profile(ent->rename, ent->new, 0);
		} else if (ent->new->parent) {
			struct aa_profile *parent, *newest;
			parent = rcu_dereference_protected(ent->new->parent,
						    mutex_is_locked(&ns->lock));
			newest = aa_get_newest_profile(parent);

			/* parent replaced in this atomic set? */
			if (newest != parent) {
				aa_get_profile(newest);
				aa_put_profile(parent);
				rcu_assign_pointer(ent->new->parent, newest);
			} else
				aa_put_profile(newest);
			__list_add_profile(&parent->base.profiles, ent->new);
		} else
			__list_add_profile(&ns->base.profiles, ent->new);

		aa_load_ent_free(ent);
	}
	mutex_unlock(&ns->lock);

out:
	aa_put_namespace(ns);

	if (error)
		return error;
	return size;

fail_lock:
	mutex_unlock(&ns->lock);
fail:
	error = audit_policy(op, GFP_KERNEL, name, info, error);

	list_for_each_entry_safe(ent, tmp, &lh, list) {
		list_del_init(&ent->list);
		aa_load_ent_free(ent);
	}

	goto out;
}

/**
 * aa_remove_profiles - remove profile(s) from the system
 * @fqname: name of the profile or namespace to remove  (NOT NULL)
 * @size: size of the name
 *
 * Remove a profile or sub namespace from the current namespace, so that
 * they can not be found anymore and mark them as replaced by unconfined
 *
 * NOTE: removing confinement does not restore rlimits to preconfinemnet values
 *
 * Returns: size of data consume else error code if fails
 */
ssize_t aa_remove_profiles(char *fqname, size_t size)
{
	struct aa_namespace *root, *ns = NULL;
	struct aa_profile *profile = NULL;
	const char *name = fqname, *info = NULL;
	ssize_t error = 0;

	if (*fqname == 0) {
		info = "no profile specified";
		error = -ENOENT;
		goto fail;
	}

	root = aa_current_profile()->ns;

	if (fqname[0] == ':') {
		char *ns_name;
		name = aa_split_fqname(fqname, &ns_name);
		/* released below */
		ns = aa_find_namespace(root, ns_name);
		if (!ns) {
			info = "namespace does not exist";
			error = -ENOENT;
			goto fail;
		}
	} else
		/* released below */
		ns = aa_get_namespace(root);

	if (!name) {
		/* remove namespace - can only happen if fqname[0] == ':' */
		mutex_lock(&ns->parent->lock);
		__remove_namespace(ns);
		mutex_unlock(&ns->parent->lock);
	} else {
		/* remove profile */
		mutex_lock(&ns->lock);
		profile = aa_get_profile(__lookup_profile(&ns->base, name));
		if (!profile) {
			error = -ENOENT;
			info = "profile does not exist";
			goto fail_ns_lock;
		}
		name = profile->base.hname;
		__remove_profile(profile);
		mutex_unlock(&ns->lock);
	}

	/* don't fail removal if audit fails */
	(void) audit_policy(OP_PROF_RM, GFP_KERNEL, name, info, error);
	aa_put_namespace(ns);
	aa_put_profile(profile);
	return size;

fail_ns_lock:
	mutex_unlock(&ns->lock);
	aa_put_namespace(ns);

fail:
	(void) audit_policy(OP_PROF_RM, GFP_KERNEL, name, info, error);
	return error;
}