summaryrefslogtreecommitdiff
path: root/security/apparmor/label.c
blob: e68bcedca976b9340919216cfd7bdfa55deb268b (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
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
// SPDX-License-Identifier: GPL-2.0-only
/*
 * AppArmor security module
 *
 * This file contains AppArmor label definitions
 *
 * Copyright 2017 Canonical Ltd.
 */

#include <linux/audit.h>
#include <linux/seq_file.h>
#include <linux/sort.h>

#include "include/apparmor.h"
#include "include/cred.h"
#include "include/label.h"
#include "include/policy.h"
#include "include/secid.h"


/*
 * the aa_label represents the set of profiles confining an object
 *
 * Labels maintain a reference count to the set of pointers they reference
 * Labels are ref counted by
 *   tasks and object via the security field/security context off the field
 *   code - will take a ref count on a label if it needs the label
 *          beyond what is possible with an rcu_read_lock.
 *   profiles - each profile is a label
 *   secids - a pinned secid will keep a refcount of the label it is
 *          referencing
 *   objects - inode, files, sockets, ...
 *
 * Labels are not ref counted by the label set, so they maybe removed and
 * freed when no longer in use.
 *
 */

#define PROXY_POISON 97
#define LABEL_POISON 100

static void free_proxy(struct aa_proxy *proxy)
{
	if (proxy) {
		/* p->label will not updated any more as p is dead */
		aa_put_label(rcu_dereference_protected(proxy->label, true));
		memset(proxy, 0, sizeof(*proxy));
		RCU_INIT_POINTER(proxy->label, (struct aa_label *)PROXY_POISON);
		kfree(proxy);
	}
}

void aa_proxy_kref(struct kref *kref)
{
	struct aa_proxy *proxy = container_of(kref, struct aa_proxy, count);

	free_proxy(proxy);
}

struct aa_proxy *aa_alloc_proxy(struct aa_label *label, gfp_t gfp)
{
	struct aa_proxy *new;

	new = kzalloc(sizeof(struct aa_proxy), gfp);
	if (new) {
		kref_init(&new->count);
		rcu_assign_pointer(new->label, aa_get_label(label));
	}
	return new;
}

/* requires profile list write lock held */
void __aa_proxy_redirect(struct aa_label *orig, struct aa_label *new)
{
	struct aa_label *tmp;

	AA_BUG(!orig);
	AA_BUG(!new);
	lockdep_assert_held_write(&labels_set(orig)->lock);

	tmp = rcu_dereference_protected(orig->proxy->label,
					&labels_ns(orig)->lock);
	rcu_assign_pointer(orig->proxy->label, aa_get_label(new));
	orig->flags |= FLAG_STALE;
	aa_put_label(tmp);
}

static void __proxy_share(struct aa_label *old, struct aa_label *new)
{
	struct aa_proxy *proxy = new->proxy;

	new->proxy = aa_get_proxy(old->proxy);
	__aa_proxy_redirect(old, new);
	aa_put_proxy(proxy);
}


/**
 * ns_cmp - compare ns for label set ordering
 * @a: ns to compare (NOT NULL)
 * @b: ns to compare (NOT NULL)
 *
 * Returns: <0 if a < b
 *          ==0 if a == b
 *          >0  if a > b
 */
static int ns_cmp(struct aa_ns *a, struct aa_ns *b)
{
	int res;

	AA_BUG(!a);
	AA_BUG(!b);
	AA_BUG(!a->base.hname);
	AA_BUG(!b->base.hname);

	if (a == b)
		return 0;

	res = a->level - b->level;
	if (res)
		return res;

	return strcmp(a->base.hname, b->base.hname);
}

/**
 * profile_cmp - profile comparison for set ordering
 * @a: profile to compare (NOT NULL)
 * @b: profile to compare (NOT NULL)
 *
 * Returns: <0  if a < b
 *          ==0 if a == b
 *          >0  if a > b
 */
static int profile_cmp(struct aa_profile *a, struct aa_profile *b)
{
	int res;

	AA_BUG(!a);
	AA_BUG(!b);
	AA_BUG(!a->ns);
	AA_BUG(!b->ns);
	AA_BUG(!a->base.hname);
	AA_BUG(!b->base.hname);

	if (a == b || a->base.hname == b->base.hname)
		return 0;
	res = ns_cmp(a->ns, b->ns);
	if (res)
		return res;

	return strcmp(a->base.hname, b->base.hname);
}

/**
 * vec_cmp - label comparison for set ordering
 * @a: label to compare (NOT NULL)
 * @vec: vector of profiles to compare (NOT NULL)
 * @n: length of @vec
 *
 * Returns: <0  if a < vec
 *          ==0 if a == vec
 *          >0  if a > vec
 */
static int vec_cmp(struct aa_profile **a, int an, struct aa_profile **b, int bn)
{
	int i;

	AA_BUG(!a);
	AA_BUG(!*a);
	AA_BUG(!b);
	AA_BUG(!*b);
	AA_BUG(an <= 0);
	AA_BUG(bn <= 0);

	for (i = 0; i < an && i < bn; i++) {
		int res = profile_cmp(a[i], b[i]);

		if (res != 0)
			return res;
	}

	return an - bn;
}

static bool vec_is_stale(struct aa_profile **vec, int n)
{
	int i;

	AA_BUG(!vec);

	for (i = 0; i < n; i++) {
		if (profile_is_stale(vec[i]))
			return true;
	}

	return false;
}

static bool vec_unconfined(struct aa_profile **vec, int n)
{
	int i;

	AA_BUG(!vec);

	for (i = 0; i < n; i++) {
		if (!profile_unconfined(vec[i]))
			return false;
	}

	return true;
}

static int sort_cmp(const void *a, const void *b)
{
	return profile_cmp(*(struct aa_profile **)a, *(struct aa_profile **)b);
}

/*
 * assumes vec is sorted
 * Assumes @vec has null terminator at vec[n], and will null terminate
 * vec[n - dups]
 */
static inline int unique(struct aa_profile **vec, int n)
{
	int i, pos, dups = 0;

	AA_BUG(n < 1);
	AA_BUG(!vec);

	pos = 0;
	for (i = 1; i < n; i++) {
		int res = profile_cmp(vec[pos], vec[i]);

		AA_BUG(res > 0, "vec not sorted");
		if (res == 0) {
			/* drop duplicate */
			aa_put_profile(vec[i]);
			dups++;
			continue;
		}
		pos++;
		if (dups)
			vec[pos] = vec[i];
	}

	AA_BUG(dups < 0);

	return dups;
}

/**
 * aa_vec_unique - canonical sort and unique a list of profiles
 * @n: number of refcounted profiles in the list (@n > 0)
 * @vec: list of profiles to sort and merge
 *
 * Returns: the number of duplicates eliminated == references put
 *
 * If @flags & VEC_FLAG_TERMINATE @vec has null terminator at vec[n], and will
 * null terminate vec[n - dups]
 */
int aa_vec_unique(struct aa_profile **vec, int n, int flags)
{
	int i, dups = 0;

	AA_BUG(n < 1);
	AA_BUG(!vec);

	/* vecs are usually small and inorder, have a fallback for larger */
	if (n > 8) {
		sort(vec, n, sizeof(struct aa_profile *), sort_cmp, NULL);
		dups = unique(vec, n);
		goto out;
	}

	/* insertion sort + unique in one */
	for (i = 1; i < n; i++) {
		struct aa_profile *tmp = vec[i];
		int pos, j;

		for (pos = i - 1 - dups; pos >= 0; pos--) {
			int res = profile_cmp(vec[pos], tmp);

			if (res == 0) {
				/* drop duplicate entry */
				aa_put_profile(tmp);
				dups++;
				goto continue_outer;
			} else if (res < 0)
				break;
		}
		/* pos is at entry < tmp, or index -1. Set to insert pos */
		pos++;

		for (j = i - dups; j > pos; j--)
			vec[j] = vec[j - 1];
		vec[pos] = tmp;
continue_outer:
		;
	}

	AA_BUG(dups < 0);

out:
	if (flags & VEC_FLAG_TERMINATE)
		vec[n - dups] = NULL;

	return dups;
}


void aa_label_destroy(struct aa_label *label)
{
	AA_BUG(!label);

	if (!label_isprofile(label)) {
		struct aa_profile *profile;
		struct label_it i;

		aa_put_str(label->hname);

		label_for_each(i, label, profile) {
			aa_put_profile(profile);
			label->vec[i.i] = (struct aa_profile *)
					   (LABEL_POISON + (long) i.i);
		}
	}

	if (label->proxy) {
		if (rcu_dereference_protected(label->proxy->label, true) == label)
			rcu_assign_pointer(label->proxy->label, NULL);
		aa_put_proxy(label->proxy);
	}
	aa_free_secid(label->secid);

	label->proxy = (struct aa_proxy *) PROXY_POISON + 1;
}

void aa_label_free(struct aa_label *label)
{
	if (!label)
		return;

	aa_label_destroy(label);
	kfree(label);
}

static void label_free_switch(struct aa_label *label)
{
	if (label->flags & FLAG_NS_COUNT)
		aa_free_ns(labels_ns(label));
	else if (label_isprofile(label))
		aa_free_profile(labels_profile(label));
	else
		aa_label_free(label);
}

static void label_free_rcu(struct rcu_head *head)
{
	struct aa_label *label = container_of(head, struct aa_label, rcu);

	if (label->flags & FLAG_IN_TREE)
		(void) aa_label_remove(label);
	label_free_switch(label);
}

void aa_label_kref(struct kref *kref)
{
	struct aa_label *label = container_of(kref, struct aa_label, count);
	struct aa_ns *ns = labels_ns(label);

	if (!ns) {
		/* never live, no rcu callback needed, just using the fn */
		label_free_switch(label);
		return;
	}
	/* TODO: update labels_profile macro so it works here */
	AA_BUG(label_isprofile(label) &&
	       on_list_rcu(&label->vec[0]->base.profiles));
	AA_BUG(label_isprofile(label) &&
	       on_list_rcu(&label->vec[0]->base.list));

	/* TODO: if compound label and not stale add to reclaim cache */
	call_rcu(&label->rcu, label_free_rcu);
}

static void label_free_or_put_new(struct aa_label *label, struct aa_label *new)
{
	if (label != new)
		/* need to free directly to break circular ref with proxy */
		aa_label_free(new);
	else
		aa_put_label(new);
}

bool aa_label_init(struct aa_label *label, int size, gfp_t gfp)
{
	AA_BUG(!label);
	AA_BUG(size < 1);

	if (aa_alloc_secid(label, gfp) < 0)
		return false;

	label->size = size;			/* doesn't include null */
	label->vec[size] = NULL;		/* null terminate */
	kref_init(&label->count);
	RB_CLEAR_NODE(&label->node);

	return true;
}

/**
 * aa_label_alloc - allocate a label with a profile vector of @size length
 * @size: size of profile vector in the label
 * @proxy: proxy to use OR null if to allocate a new one
 * @gfp: memory allocation type
 *
 * Returns: new label
 *     else NULL if failed
 */
struct aa_label *aa_label_alloc(int size, struct aa_proxy *proxy, gfp_t gfp)
{
	struct aa_label *new;

	AA_BUG(size < 1);

	/*  + 1 for null terminator entry on vec */
	new = kzalloc(sizeof(*new) + sizeof(struct aa_profile *) * (size + 1),
			gfp);
	AA_DEBUG("%s (%p)\n", __func__, new);
	if (!new)
		goto fail;

	if (!aa_label_init(new, size, gfp))
		goto fail;

	if (!proxy) {
		proxy = aa_alloc_proxy(new, gfp);
		if (!proxy)
			goto fail;
	} else
		aa_get_proxy(proxy);
	/* just set new's proxy, don't redirect proxy here if it was passed in*/
	new->proxy = proxy;

	return new;

fail:
	kfree(new);

	return NULL;
}


/**
 * label_cmp - label comparison for set ordering
 * @a: label to compare (NOT NULL)
 * @b: label to compare (NOT NULL)
 *
 * Returns: <0  if a < b
 *          ==0 if a == b
 *          >0  if a > b
 */
static int label_cmp(struct aa_label *a, struct aa_label *b)
{
	AA_BUG(!b);

	if (a == b)
		return 0;

	return vec_cmp(a->vec, a->size, b->vec, b->size);
}

/* helper fn for label_for_each_confined */
int aa_label_next_confined(struct aa_label *label, int i)
{
	AA_BUG(!label);
	AA_BUG(i < 0);

	for (; i < label->size; i++) {
		if (!profile_unconfined(label->vec[i]))
			return i;
	}

	return i;
}

/**
 * aa_label_next_not_in_set - return the next profile of @sub not in @set
 * @I: label iterator
 * @set: label to test against
 * @sub: label to if is subset of @set
 *
 * Returns: profile in @sub that is not in @set, with iterator set pos after
 *     else NULL if @sub is a subset of @set
 */
struct aa_profile *__aa_label_next_not_in_set(struct label_it *I,
					      struct aa_label *set,
					      struct aa_label *sub)
{
	AA_BUG(!set);
	AA_BUG(!I);
	AA_BUG(I->i < 0);
	AA_BUG(I->i > set->size);
	AA_BUG(!sub);
	AA_BUG(I->j < 0);
	AA_BUG(I->j > sub->size);

	while (I->j < sub->size && I->i < set->size) {
		int res = profile_cmp(sub->vec[I->j], set->vec[I->i]);

		if (res == 0) {
			(I->j)++;
			(I->i)++;
		} else if (res > 0)
			(I->i)++;
		else
			return sub->vec[(I->j)++];
	}

	if (I->j < sub->size)
		return sub->vec[(I->j)++];

	return NULL;
}

/**
 * aa_label_is_subset - test if @sub is a subset of @set
 * @set: label to test against
 * @sub: label to test if is subset of @set
 *
 * Returns: true if @sub is subset of @set
 *     else false
 */
bool aa_label_is_subset(struct aa_label *set, struct aa_label *sub)
{
	struct label_it i = { };

	AA_BUG(!set);
	AA_BUG(!sub);

	if (sub == set)
		return true;

	return __aa_label_next_not_in_set(&i, set, sub) == NULL;
}

/**
 * aa_label_is_unconfined_subset - test if @sub is a subset of @set
 * @set: label to test against
 * @sub: label to test if is subset of @set
 *
 * This checks for subset but taking into account unconfined. IF
 * @sub contains an unconfined profile that does not have a matching
 * unconfined in @set then this will not cause the test to fail.
 * Conversely we don't care about an unconfined in @set that is not in
 * @sub
 *
 * Returns: true if @sub is special_subset of @set
 *     else false
 */
bool aa_label_is_unconfined_subset(struct aa_label *set, struct aa_label *sub)
{
	struct label_it i = { };
	struct aa_profile *p;

	AA_BUG(!set);
	AA_BUG(!sub);

	if (sub == set)
		return true;

	do {
		p = __aa_label_next_not_in_set(&i, set, sub);
		if (p && !profile_unconfined(p))
			break;
	} while (p);

	return p == NULL;
}


/**
 * __label_remove - remove @label from the label set
 * @l: label to remove
 * @new: label to redirect to
 *
 * Requires: labels_set(@label)->lock write_lock
 * Returns:  true if the label was in the tree and removed
 */
static bool __label_remove(struct aa_label *label, struct aa_label *new)
{
	struct aa_labelset *ls = labels_set(label);

	AA_BUG(!ls);
	AA_BUG(!label);
	lockdep_assert_held_write(&ls->lock);

	if (new)
		__aa_proxy_redirect(label, new);

	if (!label_is_stale(label))
		__label_make_stale(label);

	if (label->flags & FLAG_IN_TREE) {
		rb_erase(&label->node, &ls->root);
		label->flags &= ~FLAG_IN_TREE;
		return true;
	}

	return false;
}

/**
 * __label_replace - replace @old with @new in label set
 * @old: label to remove from label set
 * @new: label to replace @old with
 *
 * Requires: labels_set(@old)->lock write_lock
 *           valid ref count be held on @new
 * Returns: true if @old was in set and replaced by @new
 *
 * Note: current implementation requires label set be order in such a way
 *       that @new directly replaces @old position in the set (ie.
 *       using pointer comparison of the label address would not work)
 */
static bool __label_replace(struct aa_label *old, struct aa_label *new)
{
	struct aa_labelset *ls = labels_set(old);

	AA_BUG(!ls);
	AA_BUG(!old);
	AA_BUG(!new);
	lockdep_assert_held_write(&ls->lock);
	AA_BUG(new->flags & FLAG_IN_TREE);

	if (!label_is_stale(old))
		__label_make_stale(old);

	if (old->flags & FLAG_IN_TREE) {
		rb_replace_node(&old->node, &new->node, &ls->root);
		old->flags &= ~FLAG_IN_TREE;
		new->flags |= FLAG_IN_TREE;
		return true;
	}

	return false;
}

/**
 * __label_insert - attempt to insert @l into a label set
 * @ls: set of labels to insert @l into (NOT NULL)
 * @label: new label to insert (NOT NULL)
 * @replace: whether insertion should replace existing entry that is not stale
 *
 * Requires: @ls->lock
 *           caller to hold a valid ref on l
 *           if @replace is true l has a preallocated proxy associated
 * Returns: @l if successful in inserting @l - with additional refcount
 *          else ref counted equivalent label that is already in the set,
 *          the else condition only happens if @replace is false
 */
static struct aa_label *__label_insert(struct aa_labelset *ls,
				       struct aa_label *label, bool replace)
{
	struct rb_node **new, *parent = NULL;

	AA_BUG(!ls);
	AA_BUG(!label);
	AA_BUG(labels_set(label) != ls);
	lockdep_assert_held_write(&ls->lock);
	AA_BUG(label->flags & FLAG_IN_TREE);

	/* Figure out where to put new node */
	new = &ls->root.rb_node;
	while (*new) {
		struct aa_label *this = rb_entry(*new, struct aa_label, node);
		int result = label_cmp(label, this);

		parent = *new;
		if (result == 0) {
			/* !__aa_get_label means queued for destruction,
			 * so replace in place, however the label has
			 * died before the replacement so do not share
			 * the proxy
			 */
			if (!replace && !label_is_stale(this)) {
				if (__aa_get_label(this))
					return this;
			} else
				__proxy_share(this, label);
			AA_BUG(!__label_replace(this, label));
			return aa_get_label(label);
		} else if (result < 0)
			new = &((*new)->rb_left);
		else /* (result > 0) */
			new = &((*new)->rb_right);
	}

	/* Add new node and rebalance tree. */
	rb_link_node(&label->node, parent, new);
	rb_insert_color(&label->node, &ls->root);
	label->flags |= FLAG_IN_TREE;

	return aa_get_label(label);
}

/**
 * __vec_find - find label that matches @vec in label set
 * @vec: vec of profiles to find matching label for (NOT NULL)
 * @n: length of @vec
 *
 * Requires: @vec_labelset(vec) lock held
 *           caller to hold a valid ref on l
 *
 * Returns: ref counted @label if matching label is in tree
 *          ref counted label that is equiv to @l in tree
 *     else NULL if @vec equiv is not in tree
 */
static struct aa_label *__vec_find(struct aa_profile **vec, int n)
{
	struct rb_node *node;

	AA_BUG(!vec);
	AA_BUG(!*vec);
	AA_BUG(n <= 0);

	node = vec_labelset(vec, n)->root.rb_node;
	while (node) {
		struct aa_label *this = rb_entry(node, struct aa_label, node);
		int result = vec_cmp(this->vec, this->size, vec, n);

		if (result > 0)
			node = node->rb_left;
		else if (result < 0)
			node = node->rb_right;
		else
			return __aa_get_label(this);
	}

	return NULL;
}

/**
 * __label_find - find label @label in label set
 * @label: label to find (NOT NULL)
 *
 * Requires: labels_set(@label)->lock held
 *           caller to hold a valid ref on l
 *
 * Returns: ref counted @label if @label is in tree OR
 *          ref counted label that is equiv to @label in tree
 *     else NULL if @label or equiv is not in tree
 */
static struct aa_label *__label_find(struct aa_label *label)
{
	AA_BUG(!label);

	return __vec_find(label->vec, label->size);
}


/**
 * aa_label_remove - remove a label from the labelset
 * @label: label to remove
 *
 * Returns: true if @label was removed from the tree
 *     else @label was not in tree so it could not be removed
 */
bool aa_label_remove(struct aa_label *label)
{
	struct aa_labelset *ls = labels_set(label);
	unsigned long flags;
	bool res;

	AA_BUG(!ls);

	write_lock_irqsave(&ls->lock, flags);
	res = __label_remove(label, ns_unconfined(labels_ns(label)));
	write_unlock_irqrestore(&ls->lock, flags);

	return res;
}

/**
 * aa_label_replace - replace a label @old with a new version @new
 * @old: label to replace
 * @new: label replacing @old
 *
 * Returns: true if @old was in tree and replaced
 *     else @old was not in tree, and @new was not inserted
 */
bool aa_label_replace(struct aa_label *old, struct aa_label *new)
{
	unsigned long flags;
	bool res;

	if (name_is_shared(old, new) && labels_ns(old) == labels_ns(new)) {
		write_lock_irqsave(&labels_set(old)->lock, flags);
		if (old->proxy != new->proxy)
			__proxy_share(old, new);
		else
			__aa_proxy_redirect(old, new);
		res = __label_replace(old, new);
		write_unlock_irqrestore(&labels_set(old)->lock, flags);
	} else {
		struct aa_label *l;
		struct aa_labelset *ls = labels_set(old);

		write_lock_irqsave(&ls->lock, flags);
		res = __label_remove(old, new);
		if (labels_ns(old) != labels_ns(new)) {
			write_unlock_irqrestore(&ls->lock, flags);
			ls = labels_set(new);
			write_lock_irqsave(&ls->lock, flags);
		}
		l = __label_insert(ls, new, true);
		res = (l == new);
		write_unlock_irqrestore(&ls->lock, flags);
		aa_put_label(l);
	}

	return res;
}

/**
 * vec_find - find label @l in label set
 * @vec: array of profiles to find equiv label for (NOT NULL)
 * @n: length of @vec
 *
 * Returns: refcounted label if @vec equiv is in tree
 *     else NULL if @vec equiv is not in tree
 */
static struct aa_label *vec_find(struct aa_profile **vec, int n)
{
	struct aa_labelset *ls;
	struct aa_label *label;
	unsigned long flags;

	AA_BUG(!vec);
	AA_BUG(!*vec);
	AA_BUG(n <= 0);

	ls = vec_labelset(vec, n);
	read_lock_irqsave(&ls->lock, flags);
	label = __vec_find(vec, n);
	read_unlock_irqrestore(&ls->lock, flags);

	return label;
}

/* requires sort and merge done first */
static struct aa_label *vec_create_and_insert_label(struct aa_profile **vec,
						    int len, gfp_t gfp)
{
	struct aa_label *label = NULL;
	struct aa_labelset *ls;
	unsigned long flags;
	struct aa_label *new;
	int i;

	AA_BUG(!vec);

	if (len == 1)
		return aa_get_label(&vec[0]->label);

	ls = labels_set(&vec[len - 1]->label);

	/* TODO: enable when read side is lockless
	 * check if label exists before taking locks
	 */
	new = aa_label_alloc(len, NULL, gfp);
	if (!new)
		return NULL;

	for (i = 0; i < len; i++)
		new->vec[i] = aa_get_profile(vec[i]);

	write_lock_irqsave(&ls->lock, flags);
	label = __label_insert(ls, new, false);
	write_unlock_irqrestore(&ls->lock, flags);
	label_free_or_put_new(label, new);

	return label;
}

struct aa_label *aa_vec_find_or_create_label(struct aa_profile **vec, int len,
					     gfp_t gfp)
{
	struct aa_label *label = vec_find(vec, len);

	if (label)
		return label;

	return vec_create_and_insert_label(vec, len, gfp);
}

/**
 * aa_label_find - find label @label in label set
 * @label: label to find (NOT NULL)
 *
 * Requires: caller to hold a valid ref on l
 *
 * Returns: refcounted @label if @label is in tree
 *          refcounted label that is equiv to @label in tree
 *     else NULL if @label or equiv is not in tree
 */
struct aa_label *aa_label_find(struct aa_label *label)
{
	AA_BUG(!label);

	return vec_find(label->vec, label->size);
}


/**
 * aa_label_insert - insert label @label into @ls or return existing label
 * @ls - labelset to insert @label into
 * @label - label to insert
 *
 * Requires: caller to hold a valid ref on @label
 *
 * Returns: ref counted @label if successful in inserting @label
 *     else ref counted equivalent label that is already in the set
 */
struct aa_label *aa_label_insert(struct aa_labelset *ls, struct aa_label *label)
{
	struct aa_label *l;
	unsigned long flags;

	AA_BUG(!ls);
	AA_BUG(!label);

	/* check if label exists before taking lock */
	if (!label_is_stale(label)) {
		read_lock_irqsave(&ls->lock, flags);
		l = __label_find(label);
		read_unlock_irqrestore(&ls->lock, flags);
		if (l)
			return l;
	}

	write_lock_irqsave(&ls->lock, flags);
	l = __label_insert(ls, label, false);
	write_unlock_irqrestore(&ls->lock, flags);

	return l;
}


/**
 * aa_label_next_in_merge - find the next profile when merging @a and @b
 * @I: label iterator
 * @a: label to merge
 * @b: label to merge
 *
 * Returns: next profile
 *     else null if no more profiles
 */
struct aa_profile *aa_label_next_in_merge(struct label_it *I,
					  struct aa_label *a,
					  struct aa_label *b)
{
	AA_BUG(!a);
	AA_BUG(!b);
	AA_BUG(!I);
	AA_BUG(I->i < 0);
	AA_BUG(I->i > a->size);
	AA_BUG(I->j < 0);
	AA_BUG(I->j > b->size);

	if (I->i < a->size) {
		if (I->j < b->size) {
			int res = profile_cmp(a->vec[I->i], b->vec[I->j]);

			if (res > 0)
				return b->vec[(I->j)++];
			if (res == 0)
				(I->j)++;
		}

		return a->vec[(I->i)++];
	}

	if (I->j < b->size)
		return b->vec[(I->j)++];

	return NULL;
}

/**
 * label_merge_cmp - cmp of @a merging with @b against @z for set ordering
 * @a: label to merge then compare (NOT NULL)
 * @b: label to merge then compare (NOT NULL)
 * @z: label to compare merge against (NOT NULL)
 *
 * Assumes: using the most recent versions of @a, @b, and @z
 *
 * Returns: <0  if a < b
 *          ==0 if a == b
 *          >0  if a > b
 */
static int label_merge_cmp(struct aa_label *a, struct aa_label *b,
			   struct aa_label *z)
{
	struct aa_profile *p = NULL;
	struct label_it i = { };
	int k;

	AA_BUG(!a);
	AA_BUG(!b);
	AA_BUG(!z);

	for (k = 0;
	     k < z->size && (p = aa_label_next_in_merge(&i, a, b));
	     k++) {
		int res = profile_cmp(p, z->vec[k]);

		if (res != 0)
			return res;
	}

	if (p)
		return 1;
	else if (k < z->size)
		return -1;
	return 0;
}

/**
 * label_merge_insert - create a new label by merging @a and @b
 * @new: preallocated label to merge into (NOT NULL)
 * @a: label to merge with @b  (NOT NULL)
 * @b: label to merge with @a  (NOT NULL)
 *
 * Requires: preallocated proxy
 *
 * Returns: ref counted label either @new if merge is unique
 *          @a if @b is a subset of @a
 *          @b if @a is a subset of @b
 *
 * NOTE: will not use @new if the merge results in @new == @a or @b
 *
 *       Must be used within labelset write lock to avoid racing with
 *       setting labels stale.
 */
static struct aa_label *label_merge_insert(struct aa_label *new,
					   struct aa_label *a,
					   struct aa_label *b)
{
	struct aa_label *label;
	struct aa_labelset *ls;
	struct aa_profile *next;
	struct label_it i;
	unsigned long flags;
	int k = 0, invcount = 0;
	bool stale = false;

	AA_BUG(!a);
	AA_BUG(a->size < 0);
	AA_BUG(!b);
	AA_BUG(b->size < 0);
	AA_BUG(!new);
	AA_BUG(new->size < a->size + b->size);

	label_for_each_in_merge(i, a, b, next) {
		AA_BUG(!next);
		if (profile_is_stale(next)) {
			new->vec[k] = aa_get_newest_profile(next);
			AA_BUG(!new->vec[k]->label.proxy);
			AA_BUG(!new->vec[k]->label.proxy->label);
			if (next->label.proxy != new->vec[k]->label.proxy)
				invcount++;
			k++;
			stale = true;
		} else
			new->vec[k++] = aa_get_profile(next);
	}
	/* set to actual size which is <= allocated len */
	new->size = k;
	new->vec[k] = NULL;

	if (invcount) {
		new->size -= aa_vec_unique(&new->vec[0], new->size,
					   VEC_FLAG_TERMINATE);
		/* TODO: deal with reference labels */
		if (new->size == 1) {
			label = aa_get_label(&new->vec[0]->label);
			return label;
		}
	} else if (!stale) {
		/*
		 * merge could be same as a || b, note: it is not possible
		 * for new->size == a->size == b->size unless a == b
		 */
		if (k == a->size)
			return aa_get_label(a);
		else if (k == b->size)
			return aa_get_label(b);
	}
	if (vec_unconfined(new->vec, new->size))
		new->flags |= FLAG_UNCONFINED;
	ls = labels_set(new);
	write_lock_irqsave(&ls->lock, flags);
	label = __label_insert(labels_set(new), new, false);
	write_unlock_irqrestore(&ls->lock, flags);

	return label;
}

/**
 * labelset_of_merge - find which labelset a merged label should be inserted
 * @a: label to merge and insert
 * @b: label to merge and insert
 *
 * Returns: labelset that the merged label should be inserted into
 */
static struct aa_labelset *labelset_of_merge(struct aa_label *a,
					     struct aa_label *b)
{
	struct aa_ns *nsa = labels_ns(a);
	struct aa_ns *nsb = labels_ns(b);

	if (ns_cmp(nsa, nsb) <= 0)
		return &nsa->labels;
	return &nsb->labels;
}

/**
 * __label_find_merge - find label that is equiv to merge of @a and @b
 * @ls: set of labels to search (NOT NULL)
 * @a: label to merge with @b  (NOT NULL)
 * @b: label to merge with @a  (NOT NULL)
 *
 * Requires: ls->lock read_lock held
 *
 * Returns: ref counted label that is equiv to merge of @a and @b
 *     else NULL if merge of @a and @b is not in set
 */
static struct aa_label *__label_find_merge(struct aa_labelset *ls,
					   struct aa_label *a,
					   struct aa_label *b)
{
	struct rb_node *node;

	AA_BUG(!ls);
	AA_BUG(!a);
	AA_BUG(!b);

	if (a == b)
		return __label_find(a);

	node  = ls->root.rb_node;
	while (node) {
		struct aa_label *this = container_of(node, struct aa_label,
						     node);
		int result = label_merge_cmp(a, b, this);

		if (result < 0)
			node = node->rb_left;
		else if (result > 0)
			node = node->rb_right;
		else
			return __aa_get_label(this);
	}

	return NULL;
}


/**
 * aa_label_find_merge - find label that is equiv to merge of @a and @b
 * @a: label to merge with @b  (NOT NULL)
 * @b: label to merge with @a  (NOT NULL)
 *
 * Requires: labels be fully constructed with a valid ns
 *
 * Returns: ref counted label that is equiv to merge of @a and @b
 *     else NULL if merge of @a and @b is not in set
 */
struct aa_label *aa_label_find_merge(struct aa_label *a, struct aa_label *b)
{
	struct aa_labelset *ls;
	struct aa_label *label, *ar = NULL, *br = NULL;
	unsigned long flags;

	AA_BUG(!a);
	AA_BUG(!b);

	if (label_is_stale(a))
		a = ar = aa_get_newest_label(a);
	if (label_is_stale(b))
		b = br = aa_get_newest_label(b);
	ls = labelset_of_merge(a, b);
	read_lock_irqsave(&ls->lock, flags);
	label = __label_find_merge(ls, a, b);
	read_unlock_irqrestore(&ls->lock, flags);
	aa_put_label(ar);
	aa_put_label(br);

	return label;
}

/**
 * aa_label_merge - attempt to insert new merged label of @a and @b
 * @ls: set of labels to insert label into (NOT NULL)
 * @a: label to merge with @b  (NOT NULL)
 * @b: label to merge with @a  (NOT NULL)
 * @gfp: memory allocation type
 *
 * Requires: caller to hold valid refs on @a and @b
 *           labels be fully constructed with a valid ns
 *
 * Returns: ref counted new label if successful in inserting merge of a & b
 *     else ref counted equivalent label that is already in the set.
 *     else NULL if could not create label (-ENOMEM)
 */
struct aa_label *aa_label_merge(struct aa_label *a, struct aa_label *b,
				gfp_t gfp)
{
	struct aa_label *label = NULL;

	AA_BUG(!a);
	AA_BUG(!b);

	if (a == b)
		return aa_get_newest_label(a);

	/* TODO: enable when read side is lockless
	 * check if label exists before taking locks
	if (!label_is_stale(a) && !label_is_stale(b))
		label = aa_label_find_merge(a, b);
	*/

	if (!label) {
		struct aa_label *new;

		a = aa_get_newest_label(a);
		b = aa_get_newest_label(b);

		/* could use label_merge_len(a, b), but requires double
		 * comparison for small savings
		 */
		new = aa_label_alloc(a->size + b->size, NULL, gfp);
		if (!new)
			goto out;

		label = label_merge_insert(new, a, b);
		label_free_or_put_new(label, new);
out:
		aa_put_label(a);
		aa_put_label(b);
	}

	return label;
}

static inline bool label_is_visible(struct aa_profile *profile,
				    struct aa_label *label)
{
	return aa_ns_visible(profile->ns, labels_ns(label), true);
}

/* match a profile and its associated ns component if needed
 * Assumes visibility test has already been done.
 * If a subns profile is not to be matched should be prescreened with
 * visibility test.
 */
static inline unsigned int match_component(struct aa_profile *profile,
					   struct aa_profile *tp,
					   unsigned int state)
{
	const char *ns_name;

	if (profile->ns == tp->ns)
		return aa_dfa_match(profile->policy.dfa, state, tp->base.hname);

	/* try matching with namespace name and then profile */
	ns_name = aa_ns_name(profile->ns, tp->ns, true);
	state = aa_dfa_match_len(profile->policy.dfa, state, ":", 1);
	state = aa_dfa_match(profile->policy.dfa, state, ns_name);
	state = aa_dfa_match_len(profile->policy.dfa, state, ":", 1);
	return aa_dfa_match(profile->policy.dfa, state, tp->base.hname);
}

/**
 * label_compound_match - find perms for full compound label
 * @profile: profile to find perms for
 * @label: label to check access permissions for
 * @start: state to start match in
 * @subns: whether to do permission checks on components in a subns
 * @request: permissions to request
 * @perms: perms struct to set
 *
 * Returns: 0 on success else ERROR
 *
 * For the label A//&B//&C this does the perm match for A//&B//&C
 * @perms should be preinitialized with allperms OR a previous permission
 *        check to be stacked.
 */
static int label_compound_match(struct aa_profile *profile,
				struct aa_label *label,
				unsigned int state, bool subns, u32 request,
				struct aa_perms *perms)
{
	struct aa_profile *tp;
	struct label_it i;

	/* find first subcomponent that is visible */
	label_for_each(i, label, tp) {
		if (!aa_ns_visible(profile->ns, tp->ns, subns))
			continue;
		state = match_component(profile, tp, state);
		if (!state)
			goto fail;
		goto next;
	}

	/* no component visible */
	*perms = allperms;
	return 0;

next:
	label_for_each_cont(i, label, tp) {
		if (!aa_ns_visible(profile->ns, tp->ns, subns))
			continue;
		state = aa_dfa_match(profile->policy.dfa, state, "//&");
		state = match_component(profile, tp, state);
		if (!state)
			goto fail;
	}
	aa_compute_perms(profile->policy.dfa, state, perms);
	aa_apply_modes_to_perms(profile, perms);
	if ((perms->allow & request) != request)
		return -EACCES;

	return 0;

fail:
	*perms = nullperms;
	return state;
}

/**
 * label_components_match - find perms for all subcomponents of a label
 * @profile: profile to find perms for
 * @label: label to check access permissions for
 * @start: state to start match in
 * @subns: whether to do permission checks on components in a subns
 * @request: permissions to request
 * @perms: an initialized perms struct to add accumulation to
 *
 * Returns: 0 on success else ERROR
 *
 * For the label A//&B//&C this does the perm match for each of A and B and C
 * @perms should be preinitialized with allperms OR a previous permission
 *        check to be stacked.
 */
static int label_components_match(struct aa_profile *profile,
				  struct aa_label *label, unsigned int start,
				  bool subns, u32 request,
				  struct aa_perms *perms)
{
	struct aa_profile *tp;
	struct label_it i;
	struct aa_perms tmp;
	unsigned int state = 0;

	/* find first subcomponent to test */
	label_for_each(i, label, tp) {
		if (!aa_ns_visible(profile->ns, tp->ns, subns))
			continue;
		state = match_component(profile, tp, start);
		if (!state)
			goto fail;
		goto next;
	}

	/* no subcomponents visible - no change in perms */
	return 0;

next:
	aa_compute_perms(profile->policy.dfa, state, &tmp);
	aa_apply_modes_to_perms(profile, &tmp);
	aa_perms_accum(perms, &tmp);
	label_for_each_cont(i, label, tp) {
		if (!aa_ns_visible(profile->ns, tp->ns, subns))
			continue;
		state = match_component(profile, tp, start);
		if (!state)
			goto fail;
		aa_compute_perms(profile->policy.dfa, state, &tmp);
		aa_apply_modes_to_perms(profile, &tmp);
		aa_perms_accum(perms, &tmp);
	}

	if ((perms->allow & request) != request)
		return -EACCES;

	return 0;

fail:
	*perms = nullperms;
	return -EACCES;
}

/**
 * aa_label_match - do a multi-component label match
 * @profile: profile to match against (NOT NULL)
 * @label: label to match (NOT NULL)
 * @state: state to start in
 * @subns: whether to match subns components
 * @request: permission request
 * @perms: Returns computed perms (NOT NULL)
 *
 * Returns: the state the match finished in, may be the none matching state
 */
int aa_label_match(struct aa_profile *profile, struct aa_label *label,
		   unsigned int state, bool subns, u32 request,
		   struct aa_perms *perms)
{
	int error = label_compound_match(profile, label, state, subns, request,
					 perms);
	if (!error)
		return error;

	*perms = allperms;
	return label_components_match(profile, label, state, subns, request,
				      perms);
}


/**
 * aa_update_label_name - update a label to have a stored name
 * @ns: ns being viewed from (NOT NULL)
 * @label: label to update (NOT NULL)
 * @gfp: type of memory allocation
 *
 * Requires: labels_set(label) not locked in caller
 *
 * note: only updates the label name if it does not have a name already
 *       and if it is in the labelset
 */
bool aa_update_label_name(struct aa_ns *ns, struct aa_label *label, gfp_t gfp)
{
	struct aa_labelset *ls;
	unsigned long flags;
	char __counted *name;
	bool res = false;

	AA_BUG(!ns);
	AA_BUG(!label);

	if (label->hname || labels_ns(label) != ns)
		return res;

	if (aa_label_acntsxprint(&name, ns, label, FLAGS_NONE, gfp) == -1)
		return res;

	ls = labels_set(label);
	write_lock_irqsave(&ls->lock, flags);
	if (!label->hname && label->flags & FLAG_IN_TREE) {
		label->hname = name;
		res = true;
	} else
		aa_put_str(name);
	write_unlock_irqrestore(&ls->lock, flags);

	return res;
}

/*
 * cached label name is present and visible
 * @label->hname only exists if label is namespace hierachical
 */
static inline bool use_label_hname(struct aa_ns *ns, struct aa_label *label,
				   int flags)
{
	if (label->hname && (!ns || labels_ns(label) == ns) &&
	    !(flags & ~FLAG_SHOW_MODE))
		return true;

	return false;
}

/* helper macro for snprint routines */
#define update_for_len(total, len, size, str)	\
do {					\
	size_t ulen = len;		\
					\
	AA_BUG(len < 0);		\
	total += ulen;			\
	ulen = min(ulen, size);		\
	size -= ulen;			\
	str += ulen;			\
} while (0)

/**
 * aa_profile_snxprint - print a profile name to a buffer
 * @str: buffer to write to. (MAY BE NULL if @size == 0)
 * @size: size of buffer
 * @view: namespace profile is being viewed from
 * @profile: profile to view (NOT NULL)
 * @flags: whether to include the mode string
 * @prev_ns: last ns printed when used in compound print
 *
 * Returns: size of name written or would be written if larger than
 *          available buffer
 *
 * Note: will not print anything if the profile is not visible
 */
static int aa_profile_snxprint(char *str, size_t size, struct aa_ns *view,
			       struct aa_profile *profile, int flags,
			       struct aa_ns **prev_ns)
{
	const char *ns_name = NULL;

	AA_BUG(!str && size != 0);
	AA_BUG(!profile);

	if (!view)
		view = profiles_ns(profile);

	if (view != profile->ns &&
	    (!prev_ns || (*prev_ns != profile->ns))) {
		if (prev_ns)
			*prev_ns = profile->ns;
		ns_name = aa_ns_name(view, profile->ns,
				     flags & FLAG_VIEW_SUBNS);
		if (ns_name == aa_hidden_ns_name) {
			if (flags & FLAG_HIDDEN_UNCONFINED)
				return snprintf(str, size, "%s", "unconfined");
			return snprintf(str, size, "%s", ns_name);
		}
	}

	if ((flags & FLAG_SHOW_MODE) && profile != profile->ns->unconfined) {
		const char *modestr = aa_profile_mode_names[profile->mode];

		if (ns_name)
			return snprintf(str, size, ":%s:%s (%s)", ns_name,
					profile->base.hname, modestr);
		return snprintf(str, size, "%s (%s)", profile->base.hname,
				modestr);
	}

	if (ns_name)
		return snprintf(str, size, ":%s:%s", ns_name,
				profile->base.hname);
	return snprintf(str, size, "%s", profile->base.hname);
}

static const char *label_modename(struct aa_ns *ns, struct aa_label *label,
				  int flags)
{
	struct aa_profile *profile;
	struct label_it i;
	int mode = -1, count = 0;

	label_for_each(i, label, profile) {
		if (aa_ns_visible(ns, profile->ns, flags & FLAG_VIEW_SUBNS)) {
			count++;
			if (profile == profile->ns->unconfined)
				/* special case unconfined so stacks with
				 * unconfined don't report as mixed. ie.
				 * profile_foo//&:ns1:unconfined (mixed)
				 */
				continue;
			if (mode == -1)
				mode = profile->mode;
			else if (mode != profile->mode)
				return "mixed";
		}
	}

	if (count == 0)
		return "-";
	if (mode == -1)
		/* everything was unconfined */
		mode = APPARMOR_UNCONFINED;

	return aa_profile_mode_names[mode];
}

/* if any visible label is not unconfined the display_mode returns true */
static inline bool display_mode(struct aa_ns *ns, struct aa_label *label,
				int flags)
{
	if ((flags & FLAG_SHOW_MODE)) {
		struct aa_profile *profile;
		struct label_it i;

		label_for_each(i, label, profile) {
			if (aa_ns_visible(ns, profile->ns,
					  flags & FLAG_VIEW_SUBNS) &&
			    profile != profile->ns->unconfined)
				return true;
		}
		/* only ns->unconfined in set of profiles in ns */
		return false;
	}

	return false;
}

/**
 * aa_label_snxprint - print a label name to a string buffer
 * @str: buffer to write to. (MAY BE NULL if @size == 0)
 * @size: size of buffer
 * @ns: namespace profile is being viewed from
 * @label: label to view (NOT NULL)
 * @flags: whether to include the mode string
 *
 * Returns: size of name written or would be written if larger than
 *          available buffer
 *
 * Note: labels do not have to be strictly hierarchical to the ns as
 *       objects may be shared across different namespaces and thus
 *       pickup labeling from each ns.  If a particular part of the
 *       label is not visible it will just be excluded.  And if none
 *       of the label is visible "---" will be used.
 */
int aa_label_snxprint(char *str, size_t size, struct aa_ns *ns,
		      struct aa_label *label, int flags)
{
	struct aa_profile *profile;
	struct aa_ns *prev_ns = NULL;
	struct label_it i;
	int count = 0, total = 0;
	ssize_t len;

	AA_BUG(!str && size != 0);
	AA_BUG(!label);

	if (flags & FLAG_ABS_ROOT) {
		ns = root_ns;
		len = snprintf(str, size, "=");
		update_for_len(total, len, size, str);
	} else if (!ns) {
		ns = labels_ns(label);
	}

	label_for_each(i, label, profile) {
		if (aa_ns_visible(ns, profile->ns, flags & FLAG_VIEW_SUBNS)) {
			if (count > 0) {
				len = snprintf(str, size, "//&");
				update_for_len(total, len, size, str);
			}
			len = aa_profile_snxprint(str, size, ns, profile,
						  flags & FLAG_VIEW_SUBNS,
						  &prev_ns);
			update_for_len(total, len, size, str);
			count++;
		}
	}

	if (count == 0) {
		if (flags & FLAG_HIDDEN_UNCONFINED)
			return snprintf(str, size, "%s", "unconfined");
		return snprintf(str, size, "%s", aa_hidden_ns_name);
	}

	/* count == 1 && ... is for backwards compat where the mode
	 * is not displayed for 'unconfined' in the current ns
	 */
	if (display_mode(ns, label, flags)) {
		len = snprintf(str, size, " (%s)",
			       label_modename(ns, label, flags));
		update_for_len(total, len, size, str);
	}

	return total;
}
#undef update_for_len

/**
 * aa_label_asxprint - allocate a string buffer and print label into it
 * @strp: Returns - the allocated buffer with the label name. (NOT NULL)
 * @ns: namespace profile is being viewed from
 * @label: label to view (NOT NULL)
 * @flags: flags controlling what label info is printed
 * @gfp: kernel memory allocation type
 *
 * Returns: size of name written or would be written if larger than
 *          available buffer
 */
int aa_label_asxprint(char **strp, struct aa_ns *ns, struct aa_label *label,
		      int flags, gfp_t gfp)
{
	int size;

	AA_BUG(!strp);
	AA_BUG(!label);

	size = aa_label_snxprint(NULL, 0, ns, label, flags);
	if (size < 0)
		return size;

	*strp = kmalloc(size + 1, gfp);
	if (!*strp)
		return -ENOMEM;
	return aa_label_snxprint(*strp, size + 1, ns, label, flags);
}

/**
 * aa_label_acntsxprint - allocate a __counted string buffer and print label
 * @strp: buffer to write to. (MAY BE NULL if @size == 0)
 * @ns: namespace profile is being viewed from
 * @label: label to view (NOT NULL)
 * @flags: flags controlling what label info is printed
 * @gfp: kernel memory allocation type
 *
 * Returns: size of name written or would be written if larger than
 *          available buffer
 */
int aa_label_acntsxprint(char __counted **strp, struct aa_ns *ns,
			 struct aa_label *label, int flags, gfp_t gfp)
{
	int size;

	AA_BUG(!strp);
	AA_BUG(!label);

	size = aa_label_snxprint(NULL, 0, ns, label, flags);
	if (size < 0)
		return size;

	*strp = aa_str_alloc(size + 1, gfp);
	if (!*strp)
		return -ENOMEM;
	return aa_label_snxprint(*strp, size + 1, ns, label, flags);
}


void aa_label_xaudit(struct audit_buffer *ab, struct aa_ns *ns,
		     struct aa_label *label, int flags, gfp_t gfp)
{
	const char *str;
	char *name = NULL;
	int len;

	AA_BUG(!ab);
	AA_BUG(!label);

	if (!use_label_hname(ns, label, flags) ||
	    display_mode(ns, label, flags)) {
		len  = aa_label_asxprint(&name, ns, label, flags, gfp);
		if (len == -1) {
			AA_DEBUG("label print error");
			return;
		}
		str = name;
	} else {
		str = (char *) label->hname;
		len = strlen(str);
	}
	if (audit_string_contains_control(str, len))
		audit_log_n_hex(ab, str, len);
	else
		audit_log_n_string(ab, str, len);

	kfree(name);
}

void aa_label_seq_xprint(struct seq_file *f, struct aa_ns *ns,
			 struct aa_label *label, int flags, gfp_t gfp)
{
	AA_BUG(!f);
	AA_BUG(!label);

	if (!use_label_hname(ns, label, flags)) {
		char *str;
		int len;

		len = aa_label_asxprint(&str, ns, label, flags, gfp);
		if (len == -1) {
			AA_DEBUG("label print error");
			return;
		}
		seq_puts(f, str);
		kfree(str);
	} else if (display_mode(ns, label, flags))
		seq_printf(f, "%s (%s)", label->hname,
			   label_modename(ns, label, flags));
	else
		seq_puts(f, label->hname);
}

void aa_label_xprintk(struct aa_ns *ns, struct aa_label *label, int flags,
		      gfp_t gfp)
{
	AA_BUG(!label);

	if (!use_label_hname(ns, label, flags)) {
		char *str;
		int len;

		len = aa_label_asxprint(&str, ns, label, flags, gfp);
		if (len == -1) {
			AA_DEBUG("label print error");
			return;
		}
		pr_info("%s", str);
		kfree(str);
	} else if (display_mode(ns, label, flags))
		pr_info("%s (%s)", label->hname,
		       label_modename(ns, label, flags));
	else
		pr_info("%s", label->hname);
}

void aa_label_audit(struct audit_buffer *ab, struct aa_label *label, gfp_t gfp)
{
	struct aa_ns *ns = aa_get_current_ns();

	aa_label_xaudit(ab, ns, label, FLAG_VIEW_SUBNS, gfp);
	aa_put_ns(ns);
}

void aa_label_seq_print(struct seq_file *f, struct aa_label *label, gfp_t gfp)
{
	struct aa_ns *ns = aa_get_current_ns();

	aa_label_seq_xprint(f, ns, label, FLAG_VIEW_SUBNS, gfp);
	aa_put_ns(ns);
}

void aa_label_printk(struct aa_label *label, gfp_t gfp)
{
	struct aa_ns *ns = aa_get_current_ns();

	aa_label_xprintk(ns, label, FLAG_VIEW_SUBNS, gfp);
	aa_put_ns(ns);
}

static int label_count_strn_entries(const char *str, size_t n)
{
	const char *end = str + n;
	const char *split;
	int count = 1;

	AA_BUG(!str);

	for (split = aa_label_strn_split(str, end - str);
	     split;
	     split = aa_label_strn_split(str, end - str)) {
		count++;
		str = split + 3;
	}

	return count;
}

/*
 * ensure stacks with components like
 *   :ns:A//&B
 * have :ns: applied to both 'A' and 'B' by making the lookup relative
 * to the base if the lookup specifies an ns, else making the stacked lookup
 * relative to the last embedded ns in the string.
 */
static struct aa_profile *fqlookupn_profile(struct aa_label *base,
					    struct aa_label *currentbase,
					    const char *str, size_t n)
{
	const char *first = skipn_spaces(str, n);

	if (first && *first == ':')
		return aa_fqlookupn_profile(base, str, n);

	return aa_fqlookupn_profile(currentbase, str, n);
}

/**
 * aa_label_strn_parse - parse, validate and convert a text string to a label
 * @base: base label to use for lookups (NOT NULL)
 * @str: null terminated text string (NOT NULL)
 * @n: length of str to parse, will stop at \0 if encountered before n
 * @gfp: allocation type
 * @create: true if should create compound labels if they don't exist
 * @force_stack: true if should stack even if no leading &
 *
 * Returns: the matching refcounted label if present
 *     else ERRPTR
 */
struct aa_label *aa_label_strn_parse(struct aa_label *base, const char *str,
				     size_t n, gfp_t gfp, bool create,
				     bool force_stack)
{
	DEFINE_VEC(profile, vec);
	struct aa_label *label, *currbase = base;
	int i, len, stack = 0, error;
	const char *end = str + n;
	const char *split;

	AA_BUG(!base);
	AA_BUG(!str);

	str = skipn_spaces(str, n);
	if (str == NULL || (*str == '=' && base != &root_ns->unconfined->label))
		return ERR_PTR(-EINVAL);

	len = label_count_strn_entries(str, end - str);
	if (*str == '&' || force_stack) {
		/* stack on top of base */
		stack = base->size;
		len += stack;
		if (*str == '&')
			str++;
	}

	error = vec_setup(profile, vec, len, gfp);
	if (error)
		return ERR_PTR(error);

	for (i = 0; i < stack; i++)
		vec[i] = aa_get_profile(base->vec[i]);

	for (split = aa_label_strn_split(str, end - str), i = stack;
	     split && i < len; i++) {
		vec[i] = fqlookupn_profile(base, currbase, str, split - str);
		if (!vec[i])
			goto fail;
		/*
		 * if component specified a new ns it becomes the new base
		 * so that subsequent lookups are relative to it
		 */
		if (vec[i]->ns != labels_ns(currbase))
			currbase = &vec[i]->label;
		str = split + 3;
		split = aa_label_strn_split(str, end - str);
	}
	/* last element doesn't have a split */
	if (i < len) {
		vec[i] = fqlookupn_profile(base, currbase, str, end - str);
		if (!vec[i])
			goto fail;
	}
	if (len == 1)
		/* no need to free vec as len < LOCAL_VEC_ENTRIES */
		return &vec[0]->label;

	len -= aa_vec_unique(vec, len, VEC_FLAG_TERMINATE);
	/* TODO: deal with reference labels */
	if (len == 1) {
		label = aa_get_label(&vec[0]->label);
		goto out;
	}

	if (create)
		label = aa_vec_find_or_create_label(vec, len, gfp);
	else
		label = vec_find(vec, len);
	if (!label)
		goto fail;

out:
	/* use adjusted len from after vec_unique, not original */
	vec_cleanup(profile, vec, len);
	return label;

fail:
	label = ERR_PTR(-ENOENT);
	goto out;
}

struct aa_label *aa_label_parse(struct aa_label *base, const char *str,
				gfp_t gfp, bool create, bool force_stack)
{
	return aa_label_strn_parse(base, str, strlen(str), gfp, create,
				   force_stack);
}

/**
 * aa_labelset_destroy - remove all labels from the label set
 * @ls: label set to cleanup (NOT NULL)
 *
 * Labels that are removed from the set may still exist beyond the set
 * being destroyed depending on their reference counting
 */
void aa_labelset_destroy(struct aa_labelset *ls)
{
	struct rb_node *node;
	unsigned long flags;

	AA_BUG(!ls);

	write_lock_irqsave(&ls->lock, flags);
	for (node = rb_first(&ls->root); node; node = rb_first(&ls->root)) {
		struct aa_label *this = rb_entry(node, struct aa_label, node);

		if (labels_ns(this) != root_ns)
			__label_remove(this,
				       ns_unconfined(labels_ns(this)->parent));
		else
			__label_remove(this, NULL);
	}
	write_unlock_irqrestore(&ls->lock, flags);
}

/*
 * @ls: labelset to init (NOT NULL)
 */
void aa_labelset_init(struct aa_labelset *ls)
{
	AA_BUG(!ls);

	rwlock_init(&ls->lock);
	ls->root = RB_ROOT;
}

static struct aa_label *labelset_next_stale(struct aa_labelset *ls)
{
	struct aa_label *label;
	struct rb_node *node;
	unsigned long flags;

	AA_BUG(!ls);

	read_lock_irqsave(&ls->lock, flags);

	__labelset_for_each(ls, node) {
		label = rb_entry(node, struct aa_label, node);
		if ((label_is_stale(label) ||
		     vec_is_stale(label->vec, label->size)) &&
		    __aa_get_label(label))
			goto out;

	}
	label = NULL;

out:
	read_unlock_irqrestore(&ls->lock, flags);

	return label;
}

/**
 * __label_update - insert updated version of @label into labelset
 * @label - the label to update/replace
 *
 * Returns: new label that is up to date
 *     else NULL on failure
 *
 * Requires: @ns lock be held
 *
 * Note: worst case is the stale @label does not get updated and has
 *       to be updated at a later time.
 */
static struct aa_label *__label_update(struct aa_label *label)
{
	struct aa_label *new, *tmp;
	struct aa_labelset *ls;
	unsigned long flags;
	int i, invcount = 0;

	AA_BUG(!label);
	AA_BUG(!mutex_is_locked(&labels_ns(label)->lock));

	new = aa_label_alloc(label->size, label->proxy, GFP_KERNEL);
	if (!new)
		return NULL;

	/*
	 * while holding the ns_lock will stop profile replacement, removal,
	 * and label updates, label merging and removal can be occurring
	 */
	ls = labels_set(label);
	write_lock_irqsave(&ls->lock, flags);
	for (i = 0; i < label->size; i++) {
		AA_BUG(!label->vec[i]);
		new->vec[i] = aa_get_newest_profile(label->vec[i]);
		AA_BUG(!new->vec[i]);
		AA_BUG(!new->vec[i]->label.proxy);
		AA_BUG(!new->vec[i]->label.proxy->label);
		if (new->vec[i]->label.proxy != label->vec[i]->label.proxy)
			invcount++;
	}

	/* updated stale label by being removed/renamed from labelset */
	if (invcount) {
		new->size -= aa_vec_unique(&new->vec[0], new->size,
					   VEC_FLAG_TERMINATE);
		/* TODO: deal with reference labels */
		if (new->size == 1) {
			tmp = aa_get_label(&new->vec[0]->label);
			AA_BUG(tmp == label);
			goto remove;
		}
		if (labels_set(label) != labels_set(new)) {
			write_unlock_irqrestore(&ls->lock, flags);
			tmp = aa_label_insert(labels_set(new), new);
			write_lock_irqsave(&ls->lock, flags);
			goto remove;
		}
	} else
		AA_BUG(labels_ns(label) != labels_ns(new));

	tmp = __label_insert(labels_set(label), new, true);
remove:
	/* ensure label is removed, and redirected correctly */
	__label_remove(label, tmp);
	write_unlock_irqrestore(&ls->lock, flags);
	label_free_or_put_new(tmp, new);

	return tmp;
}

/**
 * __labelset_update - update labels in @ns
 * @ns: namespace to update labels in  (NOT NULL)
 *
 * Requires: @ns lock be held
 *
 * Walk the labelset ensuring that all labels are up to date and valid
 * Any label that has a stale component is marked stale and replaced and
 * by an updated version.
 *
 * If failures happen due to memory pressures then stale labels will
 * be left in place until the next pass.
 */
static void __labelset_update(struct aa_ns *ns)
{
	struct aa_label *label;

	AA_BUG(!ns);
	AA_BUG(!mutex_is_locked(&ns->lock));

	do {
		label = labelset_next_stale(&ns->labels);
		if (label) {
			struct aa_label *l = __label_update(label);

			aa_put_label(l);
			aa_put_label(label);
		}
	} while (label);
}

/**
 * __aa_labelset_udate_subtree - update all labels with a stale component
 * @ns: ns to start update at (NOT NULL)
 *
 * Requires: @ns lock be held
 *
 * Invalidates labels based on @p in @ns and any children namespaces.
 */
void __aa_labelset_update_subtree(struct aa_ns *ns)
{
	struct aa_ns *child;

	AA_BUG(!ns);
	AA_BUG(!mutex_is_locked(&ns->lock));

	__labelset_update(ns);

	list_for_each_entry(child, &ns->sub_ns, base.list) {
		mutex_lock_nested(&child->lock, child->level);
		__aa_labelset_update_subtree(child);
		mutex_unlock(&child->lock);
	}
}