summaryrefslogtreecommitdiffstats
path: root/source/smbd/posix_acls.c
blob: 765bd0f3b26efa9f04c8c427229f1c430509e9f7 (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
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
/*
   Unix SMB/Netbios implementation.
   Version 1.9.
   SMB NT Security Descriptor / Unix permission conversion.
   Copyright (C) Jeremy Allison 1994-2000

   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; either version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "includes.h"

/****************************************************************************
 Data structures representing the internal ACE format.
****************************************************************************/

enum ace_owner {UID_ACE, GID_ACE, WORLD_ACE};
enum ace_attribute {ALLOW_ACE, DENY_ACE}; /* Used for incoming NT ACLS. */

typedef union posix_id {
		uid_t uid;
		gid_t gid;
		int world;
} posix_id;

typedef struct canon_ace {
	struct canon_ace *next, *prev;
	SMB_ACL_TAG_T type;
	mode_t perms; /* Only use S_I(R|W|X)USR mode bits here. */
	DOM_SID trustee;
	enum ace_owner owner_type;
	enum ace_attribute attr;
	posix_id unix_ug; 
} canon_ace;

#define ALL_ACE_PERMS (S_IRUSR|S_IWUSR|S_IXUSR)

/****************************************************************************
 Functions to manipulate the internal ACE format.
****************************************************************************/

/****************************************************************************
 Count a linked list of canonical ACE entries.
****************************************************************************/

static size_t count_canon_ace_list( canon_ace *list_head )
{
	size_t count = 0;
	canon_ace *ace;

	for (ace = list_head; ace; ace = ace->next)
		count++;

	return count;
}

/****************************************************************************
 Free a linked list of canonical ACE entries.
****************************************************************************/

static void free_canon_ace_list( canon_ace *list_head )
{
	while (list_head) {
		canon_ace *old_head = list_head;
		DLIST_REMOVE(list_head, list_head);
		SAFE_FREE(old_head);
	}
}

/****************************************************************************
 Function to duplicate a canon_ace entry.
****************************************************************************/

static canon_ace *dup_canon_ace( canon_ace *src_ace)
{
	canon_ace *dst_ace = (canon_ace *)malloc(sizeof(canon_ace));

	if (dst_ace == NULL)
		return NULL;

	*dst_ace = *src_ace;
	dst_ace->prev = dst_ace->next = NULL;
	return dst_ace;
}

/****************************************************************************
 Print out a canon ace.
****************************************************************************/

static void print_canon_ace(canon_ace *pace, int num)
{
	fstring str;

	dbgtext( "canon_ace index %d. Type = %s ", num, pace->attr == ALLOW_ACE ? "allow" : "deny" );
	dbgtext( "SID = %s ", sid_to_string( str, &pace->trustee));
	if (pace->owner_type == UID_ACE) {
		char *u_name = uidtoname(pace->unix_ug.uid);
		dbgtext( "uid %u (%s) ", (unsigned int)pace->unix_ug.uid, u_name);
	} else if (pace->owner_type == GID_ACE) {
		char *g_name = gidtoname(pace->unix_ug.gid);
		dbgtext( "gid %u (%s) ", (unsigned int)pace->unix_ug.gid, g_name);
	} else
		dbgtext( "other ");
	switch (pace->type) {
		case SMB_ACL_USER:
			dbgtext( "SMB_ACL_USER ");
			break;
		case SMB_ACL_USER_OBJ:
			dbgtext( "SMB_ACL_USER_OBJ ");
			break;
		case SMB_ACL_GROUP:
			dbgtext( "SMB_ACL_GROUP ");
			break;
		case SMB_ACL_GROUP_OBJ:
			dbgtext( "SMB_ACL_GROUP_OBJ ");
			break;
		case SMB_ACL_OTHER:
			dbgtext( "SMB_ACL_OTHER ");
			break;
	}
	dbgtext( "perms ");
	dbgtext( "%c", pace->perms & S_IRUSR ? 'r' : '-');
	dbgtext( "%c", pace->perms & S_IWUSR ? 'w' : '-');
	dbgtext( "%c\n", pace->perms & S_IXUSR ? 'x' : '-');
}

/****************************************************************************
 Print out a canon ace list.
****************************************************************************/

static void print_canon_ace_list(const char *name, canon_ace *ace_list)
{
	int count = 0;

	if( DEBUGLVL( 10 )) {
		dbgtext( "print_canon_ace_list: %s\n", name );
		for (;ace_list; ace_list = ace_list->next, count++)
			print_canon_ace(ace_list, count );
	}
}

/****************************************************************************
 Map POSIX ACL perms to canon_ace permissions (a mode_t containing only S_(R|W|X)USR bits).
****************************************************************************/

static mode_t convert_permset_to_mode_t(SMB_ACL_PERMSET_T permset)
{
	mode_t ret = 0;

	ret |= (sys_acl_get_perm(permset, SMB_ACL_READ) ? S_IRUSR : 0);
	ret |= (sys_acl_get_perm(permset, SMB_ACL_WRITE) ? S_IWUSR : 0);
	ret |= (sys_acl_get_perm(permset, SMB_ACL_EXECUTE) ? S_IXUSR : 0);

	return ret;
}

/****************************************************************************
 Map generic UNIX permissions to canon_ace permissions (a mode_t containing only S_(R|W|X)USR bits).
****************************************************************************/

static mode_t unix_perms_to_acl_perms(mode_t mode, int r_mask, int w_mask, int x_mask)
{
	mode_t ret = 0;

	if (mode & r_mask)
		ret |= S_IRUSR;
	if (mode & w_mask)
		ret |= S_IWUSR;
	if (mode & x_mask)
		ret |= S_IXUSR;

	return ret;
}

/****************************************************************************
 Map canon_ace permissions (a mode_t containing only S_(R|W|X)USR bits) to
 an SMB_ACL_PERMSET_T.
****************************************************************************/

static int map_acl_perms_to_permset(mode_t mode, SMB_ACL_PERMSET_T *p_permset)
{
	if (sys_acl_clear_perms(*p_permset) ==  -1)
		return -1;
	if (mode & S_IRUSR) {
		if (sys_acl_add_perm(*p_permset, SMB_ACL_READ) == -1)
			return -1;
	}
	if (mode & S_IWUSR) {
		if (sys_acl_add_perm(*p_permset, SMB_ACL_WRITE) == -1)
			return -1;
	}
	if (mode & S_IXUSR) {
		if (sys_acl_add_perm(*p_permset, SMB_ACL_EXECUTE) == -1)
			return -1;
	}
	return 0;
}
/****************************************************************************
 Function to create owner and group SIDs from a SMB_STRUCT_STAT.
****************************************************************************/

static void create_file_sids(SMB_STRUCT_STAT *psbuf, DOM_SID *powner_sid, DOM_SID *pgroup_sid)
{
	uid_to_sid( powner_sid, psbuf->st_uid );
	gid_to_sid( pgroup_sid, psbuf->st_gid );
}

/****************************************************************************
 Merge aces with a common sid - if both are allow or deny, OR the permissions together and
 delete the second one. If the first is deny, mask the permissions off and delete the allow
 if the permissions become zero, delete the deny if the permissions are non zero.
****************************************************************************/

static void merge_aces( canon_ace **pp_list_head )
{
	canon_ace *list_head = *pp_list_head;
	canon_ace *curr_ace_outer;
	canon_ace *curr_ace_outer_next;

	/*
	 * First, merge allow entries with identical SIDs, and deny entries
	 * with identical SIDs.
	 */

	for (curr_ace_outer = list_head; curr_ace_outer; curr_ace_outer = curr_ace_outer_next) {
		canon_ace *curr_ace;
		canon_ace *curr_ace_next;

		curr_ace_outer_next = curr_ace_outer->next; /* Save the link in case we delete. */

		for (curr_ace = curr_ace_outer->next; curr_ace; curr_ace = curr_ace_next) {

			curr_ace_next = curr_ace->next; /* Save the link in case of delete. */

			if (sid_equal(&curr_ace->trustee, &curr_ace_outer->trustee) &&
				(curr_ace->attr == curr_ace_outer->attr)) {

				if( DEBUGLVL( 10 )) {
					dbgtext("merge_aces: Merging ACE's\n");
					print_canon_ace( curr_ace_outer, 0);
					print_canon_ace( curr_ace, 0);
				}

				/* Merge two allow or two deny ACE's. */

				curr_ace_outer->perms |= curr_ace->perms;
				DLIST_REMOVE(list_head, curr_ace);
				SAFE_FREE(curr_ace);
				curr_ace_outer_next = curr_ace_outer->next; /* We may have deleted the link. */
			}
		}
	}

	/*
	 * Now go through and mask off allow permissions with deny permissions.
	 * We can delete either the allow or deny here as we know that each SID
	 * appears only once in the list.
	 */

	for (curr_ace_outer = list_head; curr_ace_outer; curr_ace_outer = curr_ace_outer_next) {
		canon_ace *curr_ace;
		canon_ace *curr_ace_next;

		curr_ace_outer_next = curr_ace_outer->next; /* Save the link in case we delete. */

		for (curr_ace = curr_ace_outer->next; curr_ace; curr_ace = curr_ace_next) {

			curr_ace_next = curr_ace->next; /* Save the link in case of delete. */

			/*
			 * Subtract ACE's with different entries. Due to the ordering constraints
			 * we've put on the ACL, we know the deny must be the first one.
			 */

			if (sid_equal(&curr_ace->trustee, &curr_ace_outer->trustee) &&
				(curr_ace_outer->attr == DENY_ACE) && (curr_ace->attr == ALLOW_ACE)) {

				if( DEBUGLVL( 10 )) {
					dbgtext("merge_aces: Masking ACE's\n");
					print_canon_ace( curr_ace_outer, 0);
					print_canon_ace( curr_ace, 0);
				}

				curr_ace->perms &= ~curr_ace_outer->perms;

				if (curr_ace->perms == 0) {

					/*
					 * The deny overrides the allow. Remove the allow.
					 */

					DLIST_REMOVE(list_head, curr_ace);
					SAFE_FREE(curr_ace);
					curr_ace_outer_next = curr_ace_outer->next; /* We may have deleted the link. */

				} else {

					/*
					 * Even after removing permissions, there
					 * are still allow permissions - delete the deny.
					 * It is safe to delete the deny here,
					 * as we are guarenteed by the deny first
					 * ordering that all the deny entries for
					 * this SID have already been merged into one
					 * before we can get to an allow ace.
					 */

					DLIST_REMOVE(list_head, curr_ace_outer);
					SAFE_FREE(curr_ace_outer);
				}
			}

		} /* end for curr_ace */
	} /* end for curr_ace_outer */

	/* We may have modified the list. */

	*pp_list_head = list_head;
}

/****************************************************************************
 Map canon_ace perms to permission bits NT.
 The attr element is not used here - we only process deny entries on set,
 not get. Deny entries are implicit on get with ace->perms = 0.
****************************************************************************/

static SEC_ACCESS map_canon_ace_perms(int *pacl_type, DOM_SID *powner_sid, canon_ace *ace)
{
	SEC_ACCESS sa;
	uint32 nt_mask = 0;

	*pacl_type = SEC_ACE_TYPE_ACCESS_ALLOWED;

	if ((ace->perms & ALL_ACE_PERMS) == ALL_ACE_PERMS) {
			nt_mask = UNIX_ACCESS_RWX;
	} else if ((ace->perms & ALL_ACE_PERMS) == (mode_t)0) {
		nt_mask = UNIX_ACCESS_NONE;
	} else {
		nt_mask |= ((ace->perms & S_IRUSR) ? UNIX_ACCESS_R : 0 );
		nt_mask |= ((ace->perms & S_IWUSR) ? UNIX_ACCESS_W : 0 );
		nt_mask |= ((ace->perms & S_IXUSR) ? UNIX_ACCESS_X : 0 );
	}

	DEBUG(10,("map_canon_ace_perms: Mapped (UNIX) %x to (NT) %x\n",
			(unsigned int)ace->perms, (unsigned int)nt_mask ));

	init_sec_access(&sa,nt_mask);
	return sa;
}

/****************************************************************************
 Map NT perms to a UNIX mode_t.
****************************************************************************/

#define FILE_SPECIFIC_READ_BITS (FILE_READ_DATA|FILE_READ_EA|FILE_READ_ATTRIBUTES)
#define FILE_SPECIFIC_WRITE_BITS (FILE_WRITE_DATA|FILE_APPEND_DATA|FILE_WRITE_EA|FILE_WRITE_ATTRIBUTES)
#define FILE_SPECIFIC_EXECUTE_BITS (FILE_EXECUTE)

static mode_t map_nt_perms( SEC_ACCESS sec_access, int type)
{
	mode_t mode = 0;

	switch(type) {
	case S_IRUSR:
		if(sec_access.mask & GENERIC_ALL_ACCESS)
			mode = S_IRUSR|S_IWUSR|S_IXUSR;
		else {
			mode |= (sec_access.mask & (GENERIC_READ_ACCESS|FILE_SPECIFIC_READ_BITS)) ? S_IRUSR : 0;
			mode |= (sec_access.mask & (GENERIC_WRITE_ACCESS|FILE_SPECIFIC_WRITE_BITS)) ? S_IWUSR : 0;
			mode |= (sec_access.mask & (GENERIC_EXECUTE_ACCESS|FILE_SPECIFIC_EXECUTE_BITS)) ? S_IXUSR : 0;
		}
		break;
	case S_IRGRP:
		if(sec_access.mask & GENERIC_ALL_ACCESS)
			mode = S_IRGRP|S_IWGRP|S_IXGRP;
		else {
			mode |= (sec_access.mask & (GENERIC_READ_ACCESS|FILE_SPECIFIC_READ_BITS)) ? S_IRGRP : 0;
			mode |= (sec_access.mask & (GENERIC_WRITE_ACCESS|FILE_SPECIFIC_WRITE_BITS)) ? S_IWGRP : 0;
			mode |= (sec_access.mask & (GENERIC_EXECUTE_ACCESS|FILE_SPECIFIC_EXECUTE_BITS)) ? S_IXGRP : 0;
		}
		break;
	case S_IROTH:
		if(sec_access.mask & GENERIC_ALL_ACCESS)
			mode = S_IROTH|S_IWOTH|S_IXOTH;
		else {
			mode |= (sec_access.mask & (GENERIC_READ_ACCESS|FILE_SPECIFIC_READ_BITS)) ? S_IROTH : 0;
			mode |= (sec_access.mask & (GENERIC_WRITE_ACCESS|FILE_SPECIFIC_WRITE_BITS)) ? S_IWOTH : 0;
			mode |= (sec_access.mask & (GENERIC_EXECUTE_ACCESS|FILE_SPECIFIC_EXECUTE_BITS)) ? S_IXOTH : 0;
		}
		break;
	}

	return mode;
}

/****************************************************************************
 Unpack a SEC_DESC into a UNIX owner and group.
****************************************************************************/

static BOOL unpack_nt_owners(SMB_STRUCT_STAT *psbuf, uid_t *puser, gid_t *pgrp, uint32 security_info_sent, SEC_DESC *psd)
{
	DOM_SID owner_sid;
	DOM_SID grp_sid;
	enum SID_NAME_USE sid_type;

	*puser = (uid_t)-1;
	*pgrp = (gid_t)-1;

	if(security_info_sent == 0) {
		DEBUG(0,("unpack_nt_owners: no security info sent !\n"));
		return True;
	}

	/*
	 * Validate the owner and group SID's.
	 */

	memset(&owner_sid, '\0', sizeof(owner_sid));
	memset(&grp_sid, '\0', sizeof(grp_sid));

	DEBUG(5,("unpack_nt_owners: validating owner_sids.\n"));

	/*
	 * Don't immediately fail if the owner sid cannot be validated.
	 * This may be a group chown only set.
	 */

	if (security_info_sent & OWNER_SECURITY_INFORMATION) {
		sid_copy(&owner_sid, psd->owner_sid);
		if (!sid_to_uid( &owner_sid, puser, &sid_type)) {
			DEBUG(3,("unpack_nt_owners: unable to validate owner sid.\n"));
			return False;
		}
 	}

	/*
	 * Don't immediately fail if the group sid cannot be validated.
	 * This may be an owner chown only set.
	 */

	if (security_info_sent & GROUP_SECURITY_INFORMATION) {
		sid_copy(&grp_sid, psd->grp_sid);
		if (!sid_to_gid( &grp_sid, pgrp, &sid_type)) {
			DEBUG(3,("unpack_nt_owners: unable to validate group sid.\n"));
			return False;
		}
	}

	DEBUG(5,("unpack_nt_owners: owner_sids validated.\n"));

	return True;
}

/****************************************************************************
 Ensure the enforced permissions for this share apply.
****************************************************************************/

static mode_t apply_default_perms(files_struct *fsp, mode_t perms, mode_t type)
{
	int snum = SNUM(fsp->conn);
	mode_t and_bits = (mode_t)0;
	mode_t or_bits = (mode_t)0;

	/* Get the initial bits to apply. */

	if (fsp->is_directory) {
		and_bits = lp_dir_security_mask(snum);
		or_bits = lp_force_dir_security_mode(snum);
	} else {
		and_bits = lp_security_mask(snum);
		or_bits = lp_force_security_mode(snum);
	}

	/* Now bounce them into the S_USR space. */	
	switch(type) {
	case S_IRUSR:
		and_bits = unix_perms_to_acl_perms(and_bits, S_IRUSR, S_IWUSR, S_IXUSR);
		or_bits = unix_perms_to_acl_perms(or_bits, S_IRUSR, S_IWUSR, S_IXUSR);
		break;
	case S_IRGRP:
		and_bits = unix_perms_to_acl_perms(and_bits, S_IRGRP, S_IWGRP, S_IXGRP);
		or_bits = unix_perms_to_acl_perms(or_bits, S_IRGRP, S_IWGRP, S_IXGRP);
		break;
	case S_IROTH:
		and_bits = unix_perms_to_acl_perms(and_bits, S_IROTH, S_IWOTH, S_IXOTH);
		or_bits = unix_perms_to_acl_perms(or_bits, S_IROTH, S_IWOTH, S_IXOTH);
		break;
	}

	return ((perms & and_bits)|or_bits);
}

/****************************************************************************
 A well formed POSIX file or default ACL has at least 3 entries, a 
 SMB_ACL_USER_OBJ, SMB_ACL_GROUP_OBJ, SMB_ACL_OTHER_OBJ.
 In addition, the owner must always have at least read access.
 When using this call on get_acl, the pst struct is valid and contains
 the mode of the file. When using this call on set_acl, the pst struct has
 been modified to have a mode containing the default for this file or directory
 type.
****************************************************************************/

static BOOL ensure_canon_entry_valid(canon_ace **pp_ace,
							files_struct *fsp,
							DOM_SID *pfile_owner_sid,
							DOM_SID *pfile_grp_sid,
							SMB_STRUCT_STAT *pst,
							BOOL setting_acl)
{
	extern DOM_SID global_sid_World;
	canon_ace *pace;
	BOOL got_user = False;
	BOOL got_grp = False;
	BOOL got_other = False;

	for (pace = *pp_ace; pace; pace = pace->next) {
		if (pace->type == SMB_ACL_USER_OBJ) {

			if (setting_acl) {
				/* Ensure owner has read access. */
				pace->perms |= S_IRUSR;
				if (fsp->is_directory)
					pace->perms |= (S_IWUSR|S_IXUSR);

				/*
				 * Ensure create mask/force create mode is respected on set.
				 */

				pace->perms = apply_default_perms(fsp, pace->perms, S_IRUSR);
			}

			got_user = True;
		} else if (pace->type == SMB_ACL_GROUP_OBJ) {

			/*
			 * Ensure create mask/force create mode is respected on set.
			 */

			if (setting_acl)
				pace->perms = apply_default_perms(fsp, pace->perms, S_IRGRP);
			got_grp = True;
		} else if (pace->type == SMB_ACL_OTHER) {

			/*
			 * Ensure create mask/force create mode is respected on set.
			 */

			if (setting_acl)
				pace->perms = apply_default_perms(fsp, pace->perms, S_IROTH);
			got_other = True;
		}
	}

	if (!got_user) {
		if ((pace = (canon_ace *)malloc(sizeof(canon_ace))) == NULL) {
			DEBUG(0,("ensure_canon_entry_valid: malloc fail.\n"));
			return False;
		}

		ZERO_STRUCTP(pace);
		pace->type = SMB_ACL_USER_OBJ;
		pace->owner_type = UID_ACE;
		pace->unix_ug.uid = pst->st_uid;
		pace->trustee = *pfile_owner_sid;
		pace->perms = unix_perms_to_acl_perms(pst->st_mode, S_IRUSR, S_IWUSR, S_IXUSR);
		pace->attr = ALLOW_ACE;

		DLIST_ADD(*pp_ace, pace);
	}

	if (!got_grp) {
		if ((pace = (canon_ace *)malloc(sizeof(canon_ace))) == NULL) {
			DEBUG(0,("ensure_canon_entry_valid: malloc fail.\n"));
			return False;
		}

		ZERO_STRUCTP(pace);
		pace->type = SMB_ACL_GROUP_OBJ;
		pace->owner_type = GID_ACE;
		pace->unix_ug.uid = pst->st_gid;
		pace->trustee = *pfile_grp_sid;
		pace->perms = unix_perms_to_acl_perms(pst->st_mode, S_IRGRP, S_IWGRP, S_IXGRP);
		pace->attr = ALLOW_ACE;

		DLIST_ADD(*pp_ace, pace);
	}

	if (!got_other) {
		if ((pace = (canon_ace *)malloc(sizeof(canon_ace))) == NULL) {
			DEBUG(0,("ensure_canon_entry_valid: malloc fail.\n"));
			return False;
		}

		ZERO_STRUCTP(pace);
		pace->type = SMB_ACL_OTHER;
		pace->owner_type = WORLD_ACE;
		pace->unix_ug.world = -1;
		pace->trustee = global_sid_World;
		pace->perms = unix_perms_to_acl_perms(pst->st_mode, S_IROTH, S_IWOTH, S_IXOTH);
		pace->attr = ALLOW_ACE;

		DLIST_ADD(*pp_ace, pace);
	}

	return True;
}

/****************************************************************************
 Unpack a SEC_DESC into two canonical ace lists.
****************************************************************************/

static BOOL create_canon_ace_lists(files_struct *fsp, 
							DOM_SID *pfile_owner_sid,
							DOM_SID *pfile_grp_sid,
							canon_ace **ppfile_ace, canon_ace **ppdir_ace,
							SEC_ACL *dacl)
{
	extern DOM_SID global_sid_World;
	extern struct generic_mapping file_generic_mapping;
	BOOL all_aces_are_inherit_only = (fsp->is_directory ? True : False);
	canon_ace *file_ace = NULL;
	canon_ace *dir_ace = NULL;
	canon_ace *tmp_ace = NULL;
	canon_ace *current_ace = NULL;
	BOOL got_dir_allow = False;
	BOOL got_file_allow = False;
	int i, j;

	*ppfile_ace = NULL;
	*ppdir_ace = NULL;

	/*
	 * Convert the incoming ACL into a more regular form.
	 */

	for(i = 0; i < dacl->num_aces; i++) {
		SEC_ACE *psa = &dacl->ace[i];

		if((psa->type != SEC_ACE_TYPE_ACCESS_ALLOWED) && (psa->type != SEC_ACE_TYPE_ACCESS_DENIED)) {
			DEBUG(3,("create_canon_ace_lists: unable to set anything but an ALLOW or DENY ACE.\n"));
			return False;
		}

		/*
		 * The security mask may be UNIX_ACCESS_NONE which should map into
		 * no permissions (we overload the WRITE_OWNER bit for this) or it
		 * should be one of the ALL/EXECUTE/READ/WRITE bits. Arrange for this
		 * to be so. Any other bits override the UNIX_ACCESS_NONE bit.
		 */

		/*
		 * Convert GENERIC bits to specific bits.
		 */
 
		se_map_generic(&psa->info.mask, &file_generic_mapping);

		psa->info.mask &= (UNIX_ACCESS_NONE|FILE_ALL_ACCESS);

		if(psa->info.mask != UNIX_ACCESS_NONE)
			psa->info.mask &= ~UNIX_ACCESS_NONE;
	}

	/*
	 * Deal with the fact that NT 4.x re-writes the canonical format
	 * that we return for default ACLs. If a directory ACE is identical
	 * to a inherited directory ACE then NT changes the bits so that the
	 * first ACE is set to OI|IO and the second ACE for this SID is set
	 * to CI. We need to repair this. JRA.
	 */

	for(i = 0; i < dacl->num_aces; i++) {
		SEC_ACE *psa1 = &dacl->ace[i];

		for (j = i + 1; j < dacl->num_aces; j++) {
			SEC_ACE *psa2 = &dacl->ace[j];

			if (psa1->info.mask != psa2->info.mask)
				continue;

			if (!sid_equal(&psa1->trustee, &psa2->trustee))
				continue;

			/*
			 * Ok - permission bits and SIDs are equal.
			 * Check if flags were re-written.
			 */

			if (psa1->flags & SEC_ACE_FLAG_INHERIT_ONLY) {

				psa1->flags |= (psa2->flags & (SEC_ACE_FLAG_CONTAINER_INHERIT|SEC_ACE_FLAG_OBJECT_INHERIT));
				psa2->flags &= ~(SEC_ACE_FLAG_CONTAINER_INHERIT|SEC_ACE_FLAG_OBJECT_INHERIT);
				
			} else if (psa2->flags & SEC_ACE_FLAG_INHERIT_ONLY) {

				psa2->flags |= (psa1->flags & (SEC_ACE_FLAG_CONTAINER_INHERIT|SEC_ACE_FLAG_OBJECT_INHERIT));
				psa1->flags &= ~(SEC_ACE_FLAG_CONTAINER_INHERIT|SEC_ACE_FLAG_OBJECT_INHERIT);
				
			}
		}
	}

	for(i = 0; i < dacl->num_aces; i++) {
		enum SID_NAME_USE sid_type;
		SEC_ACE *psa = &dacl->ace[i];

		/*
		 * Ignore non-mappable SIDs (NT Authority, BUILTIN etc).
		 */

		if (non_mappable_sid(&psa->trustee)) {
			fstring str;
			DEBUG(10,("create_canon_ace_lists: ignoring non-mappable SID %s\n",
				sid_to_string(str, &psa->trustee) ));
			continue;
		}

		/*
		 * Create a cannon_ace entry representing this NT DACL ACE.
		 */

		if ((current_ace = (canon_ace *)malloc(sizeof(canon_ace))) == NULL) {
			free_canon_ace_list(file_ace);
			free_canon_ace_list(dir_ace);
			DEBUG(0,("create_canon_ace_lists: malloc fail.\n"));
			return False;
		}

		ZERO_STRUCTP(current_ace);

		sid_copy(&current_ace->trustee, &psa->trustee);

		/*
		 * Try and work out if the SID is a user or group
		 * as we need to flag these differently for POSIX.
		 */

		if( sid_equal(&current_ace->trustee, &global_sid_World)) {
			current_ace->owner_type = WORLD_ACE;
			current_ace->unix_ug.world = -1;
		} else if (sid_to_uid( &current_ace->trustee, &current_ace->unix_ug.uid, &sid_type)) {
			current_ace->owner_type = UID_ACE;
		} else if (sid_to_gid( &current_ace->trustee, &current_ace->unix_ug.gid, &sid_type)) {
			current_ace->owner_type = GID_ACE;
		} else {
			fstring str;

			free_canon_ace_list(file_ace);
			free_canon_ace_list(dir_ace);
			SAFE_FREE(current_ace);
			DEBUG(0,("create_canon_ace_lists: unable to map SID %s to uid or gid.\n",
				sid_to_string(str, &current_ace->trustee) ));
			return False;
		}

		/*
		 * Map the given NT permissions into a UNIX mode_t containing only
		 * S_I(R|W|X)USR bits.
		 */

		current_ace->perms |= map_nt_perms( psa->info, S_IRUSR);
		current_ace->attr = (psa->type == SEC_ACE_TYPE_ACCESS_ALLOWED) ? ALLOW_ACE : DENY_ACE;

		/*
		 * Now note what kind of a POSIX ACL this should map to.
		 */

		if(sid_equal(&current_ace->trustee, pfile_owner_sid)) {

			current_ace->type = SMB_ACL_USER_OBJ;

		} else if( sid_equal(&current_ace->trustee, pfile_grp_sid)) {

			current_ace->type = SMB_ACL_GROUP_OBJ;

		} else if( sid_equal(&current_ace->trustee, &global_sid_World)) {

			current_ace->type = SMB_ACL_OTHER;

		} else {
			/*
			 * Could be a SMB_ACL_USER or SMB_ACL_GROUP. Check by
			 * looking at owner_type.
			 */

			current_ace->type = (current_ace->owner_type == UID_ACE) ? SMB_ACL_USER : SMB_ACL_GROUP;
		}

		/*
		 * Now add the created ace to either the file list, the directory
		 * list, or both. We *MUST* preserve the order here (hence we use
		 * DLIST_ADD_END) as NT ACLs are order dependent.
		 */

		if (fsp->is_directory) {

			/*
			 * We can only add to the default POSIX ACE list if the ACE is
			 * designed to be inherited by both files and directories.
			 */

			if ((psa->flags & (SEC_ACE_FLAG_OBJECT_INHERIT|SEC_ACE_FLAG_CONTAINER_INHERIT)) ==
				(SEC_ACE_FLAG_OBJECT_INHERIT|SEC_ACE_FLAG_CONTAINER_INHERIT)) {

				DLIST_ADD_END(dir_ace, current_ace, tmp_ace);

				/*
				 * Note if this was an allow ace. We can't process
				 * any further deny ace's after this.
				 */

				if (current_ace->attr == ALLOW_ACE)
					got_dir_allow = True;

				if ((current_ace->attr == DENY_ACE) && got_dir_allow) {
					DEBUG(0,("create_canon_ace_lists: malformed ACL in inheritable ACL ! \
Deny entry after Allow entry. Failing to set on file %s.\n", fsp->fsp_name ));
					free_canon_ace_list(file_ace);
					free_canon_ace_list(dir_ace);
					SAFE_FREE(current_ace);
					return False;
				}	

				if( DEBUGLVL( 10 )) {
					dbgtext("create_canon_ace_lists: adding dir ACL:\n");
					print_canon_ace( current_ace, 0);
				}

				/*
				 * If this is not an inherit only ACE we need to add a duplicate
				 * to the file acl.
				 */

				if (!(psa->flags & SEC_ACE_FLAG_INHERIT_ONLY)) {
					canon_ace *dup_ace = dup_canon_ace(current_ace);

					if (!dup_ace) {
						DEBUG(0,("create_canon_ace_lists: malloc fail !\n"));
						free_canon_ace_list(file_ace);
						free_canon_ace_list(dir_ace);
						return False;
					}

					current_ace = dup_ace;
				} else {
					current_ace = NULL;
				}
			}
		}

		/*
		 * Only add to the file ACL if not inherit only.
		 */

		if (!(psa->flags & SEC_ACE_FLAG_INHERIT_ONLY)) {
			DLIST_ADD_END(file_ace, current_ace, tmp_ace);

			/*
			 * Note if this was an allow ace. We can't process
			 * any further deny ace's after this.
			 */

			if (current_ace->attr == ALLOW_ACE)
				got_file_allow = True;

			if ((current_ace->attr == DENY_ACE) && got_file_allow) {
				DEBUG(0,("create_canon_ace_lists: malformed ACL in file ACL ! \
Deny entry after Allow entry. Failing to set on file %s.\n", fsp->fsp_name ));
				free_canon_ace_list(file_ace);
				free_canon_ace_list(dir_ace);
				SAFE_FREE(current_ace);
				return False;
			}	

			if( DEBUGLVL( 10 )) {
				dbgtext("create_canon_ace_lists: adding file ACL:\n");
				print_canon_ace( current_ace, 0);
			}
			all_aces_are_inherit_only = False;
			current_ace = NULL;
		}

		/*
		 * Free if ACE was not added.
		 */

		SAFE_FREE(current_ace);
	}

	if (fsp->is_directory && all_aces_are_inherit_only) {
		/*
		 * Windows 2000 is doing one of these weird 'inherit acl'
		 * traverses to conserve NTFS ACL resources. Just pretend
		 * there was no DACL sent. JRA.
		 */

		DEBUG(10,("create_canon_ace_lists: Win2k inherit acl traverse. Ignoring DACL.\n"));
		free_canon_ace_list(file_ace);
		free_canon_ace_list(dir_ace);
		file_ace = NULL;
		dir_ace = NULL;
	}

	*ppfile_ace = file_ace;
	*ppdir_ace = dir_ace;

	return True;
}

/****************************************************************************
 Check if a given uid/SID is in a group gid/SID. This is probably very
 expensive and will need optimisation. A *lot* of optimisation :-). JRA.
****************************************************************************/

static BOOL uid_entry_in_group( canon_ace *uid_ace, canon_ace *group_ace )
{
	extern DOM_SID global_sid_World;
	fstring u_name;
	fstring g_name;

	/* "Everyone" always matches every uid. */

	if (sid_equal(&group_ace->trustee, &global_sid_World))
		return True;

	fstrcpy(u_name, uidtoname(uid_ace->unix_ug.uid));
	fstrcpy(g_name, gidtoname(group_ace->unix_ug.gid));

	/*
	 * Due to the winbind interfaces we need to do this via names,
	 * not uids/gids.
	 */

	return user_in_group_list(u_name, g_name );
}

/****************************************************************************
 ASCII art time again... JRA :-).

 We have 3 cases to process when moving from an NT ACL to a POSIX ACL. Firstly,
 we insist the ACL is in canonical form (ie. all DENY entries preceede ALLOW
 entries). Secondly, the merge code has ensured that all duplicate SID entries for
 allow or deny have been merged, so the same SID can only appear once in the deny
 list or once in the allow list.

 We then process as follows :

 ---------------------------------------------------------------------------
 First pass - look for a Everyone DENY entry.

 If it is deny all (rwx) trunate the list at this point.
 Else, walk the list from this point and use the deny permissions of this
 entry as a mask on all following allow entries. Finally, delete
 the Everyone DENY entry (we have applied it to everything possible).

 In addition, in this pass we remove any DENY entries that have 
 no permissions (ie. they are a DENY nothing).
 ---------------------------------------------------------------------------
 Second pass - only deal with deny user entries.

 DENY user1 (perms XXX)

 new_perms = 0
 for all following allow group entries where user1 is in group
	new_perms |= group_perms;

 user1 entry perms = new_perms & ~ XXX;

 Convert the deny entry to an allow entry with the new perms and
 push to the end of the list. Note if the user was in no groups
 this maps to a specific allow nothing entry for this user.

 The common case from the NT ACL choser (userX deny all) is
 optimised so we don't do the group lookup - we just map to
 an allow nothing entry.

 What we're doing here is inferring the allow permissions the
 person setting the ACE on user1 wanted by looking at the allow
 permissions on the groups the user is currently in. This will
 be a snapshot, depending on group membership but is the best
 we can do and has the advantage of failing closed rather than
 open.
 ---------------------------------------------------------------------------
 Third pass - only deal with deny group entries.

 DENY group1 (perms XXX)

 for all following allow user entries where user is in group1
   user entry perms = user entry perms & ~ XXX;

 If there is a group Everyone allow entry with permissions YYY,
 convert the group1 entry to an allow entry and modify its
 permissions to be :

 new_perms = YYY & ~ XXX

 and push to the end of the list.

 If there is no group Everyone allow entry then convert the
 group1 entry to a allow nothing entry and push to the end of the list.

 Note that the common case from the NT ACL choser (groupX deny all)
 cannot be optimised here as we need to modify user entries who are
 in the group to change them to a deny all also.

 What we're doing here is modifying the allow permissions of
 user entries (which are more specific in POSIX ACLs) to mask
 out the explicit deny set on the group they are in. This will
 be a snapshot depending on current group membership but is the
 best we can do and has the advantage of failing closed rather
 than open.
 ---------------------------------------------------------------------------

 Note we *MUST* do the deny user pass first as this will convert deny user
 entries into allow user entries which can then be processed by the deny
 group pass.

 The above algorithm took a *lot* of thinking about - hence this
 explaination :-). JRA.
****************************************************************************/

/****************************************************************************
 Process a canon_ace list entries. This is very complex code. We need
 to go through and remove the "deny" permissions from any allow entry that matches
 the id of this entry. We have already refused any NT ACL that wasn't in correct
 order (DENY followed by ALLOW). If any allow entry ends up with zero permissions,
 we just remove it (to fail safe). We have already removed any duplicate ace
 entries. Treat an "Everyone" DENY_ACE as a special case - use it to mask all
 allow entries.
****************************************************************************/

static void process_deny_list( canon_ace **pp_ace_list )
{
	extern DOM_SID global_sid_World;
	canon_ace *ace_list = *pp_ace_list;
	canon_ace *curr_ace = NULL;
	canon_ace *curr_ace_next = NULL;

	/* Pass 1 above - look for an Everyone, deny entry. */

	for (curr_ace = ace_list; curr_ace; curr_ace = curr_ace_next) {
		canon_ace *allow_ace_p;

		curr_ace_next = curr_ace->next; /* So we can't lose the link. */

		if (curr_ace->attr != DENY_ACE)
			continue;

		if (curr_ace->perms == (mode_t)0) {

			/* Deny nothing entry - delete. */

			DLIST_REMOVE(ace_list, curr_ace);
			continue;
		}

		if (!sid_equal(&curr_ace->trustee, &global_sid_World))
			continue;

		/* JRATEST - assert. */
		SMB_ASSERT(curr_ace->owner_type == WORLD_ACE);

		if (curr_ace->perms == ALL_ACE_PERMS) {

			/*
			 * Optimisation. This is a DENY_ALL to Everyone. Truncate the
			 * list at this point including this entry.
			 */

			canon_ace *prev_entry = curr_ace->prev;

			free_canon_ace_list( curr_ace );
			if (prev_entry)
				prev_entry->next = NULL;
			else {
				/* We deleted the entire list. */
				ace_list = NULL;
			}
			break;
		}

		for (allow_ace_p = curr_ace->next; allow_ace_p; allow_ace_p = allow_ace_p->next) {

			/* 
			 * Only mask off allow entries.
			 */

			if (allow_ace_p->attr != ALLOW_ACE)
				continue;

			allow_ace_p->perms &= ~curr_ace->perms;
		}

		/*
		 * Now it's been applied, remove it.
		 */

		DLIST_REMOVE(ace_list, curr_ace);
	}

	/* Pass 2 above - deal with deny user entries. */

	for (curr_ace = ace_list; curr_ace; curr_ace = curr_ace_next) {
		mode_t new_perms = (mode_t)0;
		canon_ace *allow_ace_p;
		canon_ace *tmp_ace;

		curr_ace_next = curr_ace->next; /* So we can't lose the link. */

		if (curr_ace->attr != DENY_ACE)
			continue;

		if (curr_ace->owner_type != UID_ACE)
			continue;

		if (curr_ace->perms == ALL_ACE_PERMS) {

			/*
			 * Optimisation - this is a deny everything to this user.
			 * Convert to an allow nothing and push to the end of the list.
			 */

			curr_ace->attr = ALLOW_ACE;
			curr_ace->perms = (mode_t)0;
			DLIST_DEMOTE(ace_list, curr_ace, tmp_ace);
			continue;
		}

		for (allow_ace_p = curr_ace->next; allow_ace_p; allow_ace_p = allow_ace_p->next) {

			if (allow_ace_p->attr != ALLOW_ACE)
				continue;

			/* We process GID_ACE and WORLD_ACE entries only. */

			if (allow_ace_p->owner_type == UID_ACE)
				continue;

			if (uid_entry_in_group( curr_ace, allow_ace_p))
				new_perms |= allow_ace_p->perms;
		}

		/*
		 * Convert to a allow entry, modify the perms and push to the end
		 * of the list.
		 */

		curr_ace->attr = ALLOW_ACE;
		curr_ace->perms = (new_perms & ~curr_ace->perms);
		DLIST_DEMOTE(ace_list, curr_ace, tmp_ace);
	}

	/* Pass 3 above - deal with deny group entries. */

	for (curr_ace = ace_list; curr_ace; curr_ace = curr_ace_next) {
		canon_ace *tmp_ace;
		canon_ace *allow_ace_p;
		canon_ace *allow_everyone_p = NULL;

		curr_ace_next = curr_ace->next; /* So we can't lose the link. */

		if (curr_ace->attr != DENY_ACE)
			continue;

		if (curr_ace->owner_type != GID_ACE)
			continue;

		for (allow_ace_p = curr_ace->next; allow_ace_p; allow_ace_p = allow_ace_p->next) {

			if (allow_ace_p->attr != ALLOW_ACE)
				continue;

			/* Store a pointer to the Everyone allow, if it exists. */
			if (allow_ace_p->owner_type == WORLD_ACE)
				allow_everyone_p = allow_ace_p;

			/* We process UID_ACE entries only. */

			if (allow_ace_p->owner_type != UID_ACE)
				continue;

			/* Mask off the deny group perms. */

			if (uid_entry_in_group( allow_ace_p, curr_ace))
				allow_ace_p->perms &= ~curr_ace->perms;
		}

		/*
		 * Convert the deny to an allow with the correct perms and
		 * push to the end of the list.
		 */

		curr_ace->attr = ALLOW_ACE;
		if (allow_everyone_p)
			curr_ace->perms = allow_everyone_p->perms & ~curr_ace->perms;
		else
			curr_ace->perms = (mode_t)0;
		DLIST_DEMOTE(ace_list, curr_ace, tmp_ace);

	}

	*pp_ace_list = ace_list;
}

/****************************************************************************
 Create a default mode that will be used if a security descriptor entry has
 no user/group/world entries.
****************************************************************************/

static mode_t create_default_mode(files_struct *fsp, BOOL interitable_mode)
{
	int snum = SNUM(fsp->conn);
	mode_t and_bits = (mode_t)0;
	mode_t or_bits = (mode_t)0;
	mode_t mode = interitable_mode ? unix_mode( fsp->conn, FILE_ATTRIBUTE_ARCHIVE, fsp->fsp_name) : S_IRUSR;

	if (fsp->is_directory)
		mode |= (S_IWUSR|S_IXUSR);

	/*
	 * Now AND with the create mode/directory mode bits then OR with the
	 * force create mode/force directory mode bits.
	 */

	if (fsp->is_directory) {
		and_bits = lp_dir_security_mask(snum);
		or_bits = lp_force_dir_security_mode(snum);
	} else {
		and_bits = lp_security_mask(snum);
		or_bits = lp_force_security_mode(snum);
	}

	return ((mode & and_bits)|or_bits);
}

/****************************************************************************
 Unpack a SEC_DESC into two canonical ace lists. We don't depend on this
 succeeding.
****************************************************************************/

static BOOL unpack_canon_ace(files_struct *fsp, 
							SMB_STRUCT_STAT *pst,
							DOM_SID *pfile_owner_sid,
							DOM_SID *pfile_grp_sid,
							canon_ace **ppfile_ace, canon_ace **ppdir_ace,
							uint32 security_info_sent, SEC_DESC *psd)
{
	canon_ace *file_ace = NULL;
	canon_ace *dir_ace = NULL;

	*ppfile_ace = NULL;
	*ppdir_ace = NULL;

	if(security_info_sent == 0) {
		DEBUG(0,("unpack_canon_ace: no security info sent !\n"));
		return False;
	}

	/*
	 * If no DACL then this is a chown only security descriptor.
	 */

	if(!(security_info_sent & DACL_SECURITY_INFORMATION) || !psd->dacl)
		return True;

	/*
	 * Now go through the DACL and create the canon_ace lists.
	 */

	if (!create_canon_ace_lists( fsp, pfile_owner_sid, pfile_grp_sid,
								&file_ace, &dir_ace, psd->dacl))
		return False;

	if ((file_ace == NULL) && (dir_ace == NULL)) {
		/* W2K traverse DACL set - ignore. */
		return True;
	}

	/*
	 * Go through the canon_ace list and merge entries
	 * belonging to identical users of identical allow or deny type.
	 * We can do this as all deny entries come first, followed by
	 * all allow entries (we have mandated this before accepting this acl).
	 */

	print_canon_ace_list( "file ace - before merge", file_ace);
	merge_aces( &file_ace );

	print_canon_ace_list( "dir ace - before merge", dir_ace);
	merge_aces( &dir_ace );

	/*
	 * NT ACLs are order dependent. Go through the acl lists and
	 * process DENY entries by masking the allow entries.
	 */

	print_canon_ace_list( "file ace - before deny", file_ace);
	process_deny_list( &file_ace);

	print_canon_ace_list( "dir ace - before deny", dir_ace);
	process_deny_list( &dir_ace);

	/*
	 * A well formed POSIX file or default ACL has at least 3 entries, a 
	 * SMB_ACL_USER_OBJ, SMB_ACL_GROUP_OBJ, SMB_ACL_OTHER_OBJ
	 * and optionally a mask entry. Ensure this is the case.
	 */

	print_canon_ace_list( "file ace - before valid", file_ace);

	/*
	 * A default 3 element mode entry for a file should be r-- --- ---.
	 * A default 3 element mode entry for a directory should be rwx --- ---.
	 */

	pst->st_mode = create_default_mode(fsp, False);

	if (!ensure_canon_entry_valid(&file_ace, fsp, pfile_owner_sid, pfile_grp_sid, pst, True)) {
		free_canon_ace_list(file_ace);
		free_canon_ace_list(dir_ace);
		return False;
	}

	print_canon_ace_list( "dir ace - before valid", dir_ace);

	/*
	 * A default inheritable 3 element mode entry for a directory should be the
	 * mode Samba will use to create a file within. Ensure user rwx bits are set if
	 * it's a directory.
	 */

	pst->st_mode = create_default_mode(fsp, True);

	if (!ensure_canon_entry_valid(&dir_ace, fsp, pfile_owner_sid, pfile_grp_sid, pst, True)) {
		free_canon_ace_list(file_ace);
		free_canon_ace_list(dir_ace);
		return False;
	}

	print_canon_ace_list( "file ace - return", file_ace);
	print_canon_ace_list( "dir ace - return", dir_ace);

	*ppfile_ace = file_ace;
	*ppdir_ace = dir_ace;
	return True;

}

/******************************************************************************
 When returning permissions, try and fit NT display
 semantics if possible. Note the the canon_entries here must have been malloced.
 The list format should be - first entry = owner, followed by group and other user
 entries, last entry = other.

 Note that this doesn't exactly match the NT semantics for an ACL. As POSIX entries
 are not ordered, and match on the most specific entry rather than walking a list,
 then a simple POSIX permission of rw-r--r-- should really map to 6 entries,

 Entry 0: owner : deny all except read and write.
 Entry 1: group : deny all except read.
 Entry 2: Everyone : deny all except read.
 Entry 3: owner : allow read and write.
 Entry 4: group : allow read.
 Entry 5: Everyone : allow read.

 But NT cannot display this in their ACL editor !
********************************************************************************/

static void arrange_posix_perms( char *filename, canon_ace **pp_list_head)
{
	canon_ace *list_head = *pp_list_head;
	canon_ace *owner_ace = NULL;
	canon_ace *other_ace = NULL;
	canon_ace *ace = NULL;

	for (ace = list_head; ace; ace = ace->next) {
		if (ace->type == SMB_ACL_USER_OBJ)
			owner_ace = ace;
		else if (ace->type == SMB_ACL_OTHER) {
			/* Last ace - this is "other" */
			other_ace = ace;
		}
	}
		
	if (!owner_ace || !other_ace) {
		DEBUG(0,("arrange_posix_perms: Invalid POSIX permissions for file %s, missing owner or other.\n",
			filename ));
		return;
	}

	/*
	 * The POSIX algorithm applies to owner first, and other last,
	 * so ensure they are arranged in this order.
	 */

	if (owner_ace) {
		DLIST_PROMOTE(list_head, owner_ace);
	}

	if (other_ace) {
		DLIST_DEMOTE(list_head, other_ace, ace);
	}

	/* We have probably changed the head of the list. */

	*pp_list_head = list_head;
}
		
/****************************************************************************
 Create a linked list of canonical ACE entries.
****************************************************************************/

static canon_ace *canonicalise_acl( files_struct *fsp, SMB_ACL_T posix_acl, SMB_STRUCT_STAT *psbuf,
									DOM_SID *powner, DOM_SID *pgroup)
{
	extern DOM_SID global_sid_World;
	mode_t acl_mask = (S_IRUSR|S_IWUSR|S_IXUSR);
	canon_ace *list_head = NULL;
	canon_ace *ace = NULL;
	canon_ace *next_ace = NULL;
	int entry_id = SMB_ACL_FIRST_ENTRY;
	SMB_ACL_ENTRY_T entry;
	size_t ace_count;

	while ( posix_acl && (sys_acl_get_entry(posix_acl, entry_id, &entry) == 1)) {
		SMB_ACL_TAG_T tagtype;
		SMB_ACL_PERMSET_T permset;
		DOM_SID sid;
		posix_id unix_ug;
		enum ace_owner owner_type;

		/* get_next... */
		if (entry_id == SMB_ACL_FIRST_ENTRY)
			entry_id = SMB_ACL_NEXT_ENTRY;

		/* Is this a MASK entry ? */
		if (sys_acl_get_tag_type(entry, &tagtype) == -1)
			continue;

		if (sys_acl_get_permset(entry, &permset) == -1)
			continue;

		/* Decide which SID to use based on the ACL type. */
		switch(tagtype) {
			case SMB_ACL_USER_OBJ:
				/* Get the SID from the owner. */
				uid_to_sid( &sid, psbuf->st_uid );
				unix_ug.uid = psbuf->st_uid;
				owner_type = UID_ACE;
				break;
			case SMB_ACL_USER:
				{
					uid_t *puid = (uid_t *)sys_acl_get_qualifier(entry);
					if (puid == NULL) {
						DEBUG(0,("canonicalise_acl: Failed to get uid.\n"));
						continue;
					}
					uid_to_sid( &sid, *puid);
					unix_ug.uid = *puid;
					owner_type = UID_ACE;
					sys_acl_free_qualifier((void *)puid,tagtype);
					break;
				}
			case SMB_ACL_GROUP_OBJ:
				/* Get the SID from the owning group. */
				gid_to_sid( &sid, psbuf->st_gid );
				unix_ug.gid = psbuf->st_gid;
				owner_type = GID_ACE;
				break;
			case SMB_ACL_GROUP:
				{
					gid_t *pgid = (gid_t *)sys_acl_get_qualifier(entry);
					if (pgid == NULL) {
						DEBUG(0,("canonicalise_acl: Failed to get gid.\n"));
						continue;
					}
					gid_to_sid( &sid, *pgid);
					unix_ug.gid = *pgid;
					owner_type = GID_ACE;
					sys_acl_free_qualifier((void *)pgid,tagtype);
					break;
				}
			case SMB_ACL_MASK:
				acl_mask = convert_permset_to_mode_t(permset);
				continue; /* Don't count the mask as an entry. */
			case SMB_ACL_OTHER:
				/* Use the Everyone SID */
				sid = global_sid_World;
				unix_ug.world = -1;
				owner_type = WORLD_ACE;
				break;
			default:
				DEBUG(0,("canonicalise_acl: Unknown tagtype %u\n", (unsigned int)tagtype));
				continue;
		}

		/*
		 * Add this entry to the list.
		 */

		if ((ace = (canon_ace *)malloc(sizeof(canon_ace))) == NULL)
			goto fail;

		ZERO_STRUCTP(ace);
		ace->type = tagtype;
		ace->perms = convert_permset_to_mode_t(permset);
		ace->attr = ALLOW_ACE;
		ace->trustee = sid;
		ace->unix_ug = unix_ug;
		ace->owner_type = owner_type;

		DLIST_ADD(list_head, ace);
	}

	/*
	 * This next call will ensure we have at least a user/group/world set.
	 */

	if (!ensure_canon_entry_valid(&list_head, fsp, powner, pgroup, psbuf, False))
		goto fail;

	arrange_posix_perms(fsp->fsp_name,&list_head );

	/*
	 * Now go through the list, masking the permissions with the
	 * acl_mask. Ensure all DENY Entries are at the start of the list.
	 */

	DEBUG(10,("canonicalise_acl: ace entries before arrange :\n"));

	for ( ace_count = 0, ace = list_head; ace; ace = next_ace, ace_count++) {
		next_ace = ace->next;

		/* Masks are only applied to entries other than USER_OBJ and OTHER. */
		if (ace->type != SMB_ACL_OTHER && ace->type != SMB_ACL_USER_OBJ)
			ace->perms &= acl_mask;

		if (ace->perms == 0) {
			DLIST_PROMOTE(list_head, ace);
		}

		if( DEBUGLVL( 10 ) ) {
			print_canon_ace(ace, ace_count);
		}
	}

	print_canon_ace_list( "canonicalise_acl: ace entries after arrange", list_head );

	return list_head;

  fail:

	free_canon_ace_list(list_head);
	return NULL;
}

/****************************************************************************
 Attempt to apply an ACL to a file or directory.
****************************************************************************/

static BOOL set_canon_ace_list(files_struct *fsp, canon_ace *the_ace, BOOL default_ace, BOOL *pacl_set_support)
{
	BOOL ret = False;
	SMB_ACL_T the_acl = sys_acl_init((int)count_canon_ace_list(the_ace) + 1);
	canon_ace *p_ace;
	int i;
	SMB_ACL_ENTRY_T mask_entry;
	SMB_ACL_PERMSET_T mask_permset;
	SMB_ACL_TYPE_T the_acl_type = (default_ace ? SMB_ACL_TYPE_DEFAULT : SMB_ACL_TYPE_ACCESS);

	if (the_acl == NULL) {

		if (errno != ENOSYS) {
			/*
			 * Only print this error message if we have some kind of ACL
			 * support that's not working. Otherwise we would always get this.
			 */
			DEBUG(0,("set_canon_ace_list: Unable to init %s ACL. (%s)\n",
				default_ace ? "default" : "file", strerror(errno) ));
		}
		*pacl_set_support = False;
		return False;
	}

	for (i = 0, p_ace = the_ace; p_ace; p_ace = p_ace->next, i++ ) {
		SMB_ACL_ENTRY_T the_entry;
		SMB_ACL_PERMSET_T the_permset;

		/*
		 * Get the entry for this ACE.
		 */

		if (sys_acl_create_entry( &the_acl, &the_entry) == -1) {
			DEBUG(0,("set_canon_ace_list: Failed to create entry %d. (%s)\n",
				i, strerror(errno) ));
			goto done;
		}

		/*
		 * Ok - we now know the ACL calls should be working, don't
		 * allow fallback to chmod.
		 */

		*pacl_set_support = True;

		/*
		 * Initialise the entry from the canon_ace.
		 */

		/*
		 * First tell the entry what type of ACE this is.
		 */

		if (sys_acl_set_tag_type(the_entry, p_ace->type) == -1) {
			DEBUG(0,("set_canon_ace_list: Failed to set tag type on entry %d. (%s)\n",
				i, strerror(errno) ));
			goto done;
		}

		/*
		 * Only set the qualifier (user or group id) if the entry is a user
		 * or group id ACE.
		 */

		if ((p_ace->type == SMB_ACL_USER) || (p_ace->type == SMB_ACL_GROUP)) {
			if (sys_acl_set_qualifier(the_entry,(void *)&p_ace->unix_ug.uid) == -1) {
				DEBUG(0,("set_canon_ace_list: Failed to set qualifier on entry %d. (%s)\n",
					i, strerror(errno) ));
				goto done;
			}
		}

		/*
		 * Convert the mode_t perms in the canon_ace to a POSIX permset.
		 */

		if (sys_acl_get_permset(the_entry, &the_permset) == -1) {
			DEBUG(0,("set_canon_ace_list: Failed to get permset on entry %d. (%s)\n",
				i, strerror(errno) ));
			goto done;
		}

		if (map_acl_perms_to_permset(p_ace->perms, &the_permset) == -1) {
			DEBUG(0,("set_canon_ace_list: Failed to create permset for mode (%u) on entry %d. (%s)\n",
				(unsigned int)p_ace->perms, i, strerror(errno) ));
			goto done;
		}

		/*
		 * ..and apply them to the entry.
		 */

		if (sys_acl_set_permset(the_entry, the_permset) == -1) {
			DEBUG(0,("set_canon_ace_list: Failed to add permset on entry %d. (%s)\n",
				i, strerror(errno) ));
			goto done;
		}

		if( DEBUGLVL( 10 ))
			print_canon_ace( p_ace, i);
	}

	/*
	 * Add in a mask of rwx.
	 */

	if (sys_acl_create_entry( &the_acl, &mask_entry) == -1) {
		DEBUG(0,("set_canon_ace_list: Failed to create mask entry. (%s)\n", strerror(errno) ));
		goto done;
	}

	if (sys_acl_set_tag_type(mask_entry, SMB_ACL_MASK) == -1) {
		DEBUG(0,("set_canon_ace_list: Failed to set tag type on mask entry. (%s)\n",strerror(errno) ));
		goto done;
	}

	if (sys_acl_get_permset(mask_entry, &mask_permset) == -1) {
		DEBUG(0,("set_canon_ace_list: Failed to get mask permset. (%s)\n", strerror(errno) ));
		goto done;
	}

	if (map_acl_perms_to_permset(S_IRUSR|S_IWUSR|S_IXUSR, &mask_permset) == -1) {
		DEBUG(0,("set_canon_ace_list: Failed to create mask permset. (%s)\n", strerror(errno) ));
		goto done;
	}

	if (sys_acl_set_permset(mask_entry, mask_permset) == -1) {
		DEBUG(0,("set_canon_ace_list: Failed to add mask permset. (%s)\n", strerror(errno) ));
		goto done;
	}

	/*
	 * Check if the ACL is valid.
	 */

	if (sys_acl_valid(the_acl) == -1) {
		DEBUG(0,("set_canon_ace_list: ACL type (%s) is invalid for set (%s).\n",
				the_acl_type == SMB_ACL_TYPE_DEFAULT ? "directory default" : "file",
				strerror(errno) ));
		goto done;
	}

	/*
	 * Finally apply it to the file or directory.
	 */

	if(default_ace || fsp->is_directory || fsp->fd == -1) {
		if (sys_acl_set_file(fsp->fsp_name, the_acl_type, the_acl) == -1) {
			/*
			 * Some systems allow all the above calls and only fail with no ACL support
			 * when attempting to apply the acl. HPUX with HFS is an example of this. JRA.
			 */
			if (errno == ENOSYS)
				*pacl_set_support = False;
			DEBUG(2,("set_canon_ace_list: sys_acl_set_file type %s failed for file %s (%s).\n",
					the_acl_type == SMB_ACL_TYPE_DEFAULT ? "directory default" : "file",
					fsp->fsp_name, strerror(errno) ));
			goto done;
		}
	} else {
		if (sys_acl_set_fd(fsp->fd, the_acl) == -1) {
			/*
			 * Some systems allow all the above calls and only fail with no ACL support
			 * when attempting to apply the acl. HPUX with HFS is an example of this. JRA.
			 */
			if (errno == ENOSYS)
				*pacl_set_support = False;
			DEBUG(2,("set_canon_ace_list: sys_acl_set_file failed for file %s (%s).\n",
					fsp->fsp_name, strerror(errno) ));
			goto done;
		}
	}

	ret = True;

  done:

	if (the_acl != NULL)
	    sys_acl_free_acl(the_acl);

	return ret;
}

/****************************************************************************
 Convert a canon_ace to a generic 3 element permission - if possible.
****************************************************************************/

#define MAP_PERM(p,mask,result) (((p) & (mask)) ? (result) : 0 )

static BOOL convert_canon_ace_to_posix_perms( files_struct *fsp, canon_ace *file_ace_list, mode_t *posix_perms)
{
	int snum = SNUM(fsp->conn);
	size_t ace_count = count_canon_ace_list(file_ace_list);
	canon_ace *ace_p;
	canon_ace *owner_ace = NULL;
	canon_ace *group_ace = NULL;
	canon_ace *other_ace = NULL;
	mode_t and_bits;
	mode_t or_bits;

	if (ace_count != 3) {
		DEBUG(3,("convert_canon_ace_to_posix_perms: Too many ACE entries for file %s to convert to \
posix perms.\n", fsp->fsp_name ));
		return False;
	}

	for (ace_p = file_ace_list; ace_p; ace_p = ace_p->next) {
		if (ace_p->owner_type == UID_ACE)
			owner_ace = ace_p;
		else if (ace_p->owner_type == GID_ACE)
			group_ace = ace_p;
		else if (ace_p->owner_type == WORLD_ACE)
			other_ace = ace_p;
	}

	if (!owner_ace || !group_ace || !other_ace) {
		DEBUG(3,("convert_canon_ace_to_posix_perms: Can't get standard entries for file %s.\n",
				fsp->fsp_name ));
		return False;
	}

	*posix_perms = (mode_t)0;

	*posix_perms |= owner_ace->perms;
	*posix_perms |= MAP_PERM(group_ace->perms, S_IRUSR, S_IRGRP);
	*posix_perms |= MAP_PERM(group_ace->perms, S_IWUSR, S_IWGRP);
	*posix_perms |= MAP_PERM(group_ace->perms, S_IXUSR, S_IXGRP);
	*posix_perms |= MAP_PERM(other_ace->perms, S_IRUSR, S_IROTH);
	*posix_perms |= MAP_PERM(other_ace->perms, S_IWUSR, S_IWOTH);
	*posix_perms |= MAP_PERM(other_ace->perms, S_IXUSR, S_IXOTH);

	/* The owner must have at least read access. */

	*posix_perms |= S_IRUSR;
	if (fsp->is_directory)
		*posix_perms |= (S_IWUSR|S_IXUSR);

	/* If requested apply the masks. */

	/* Get the initial bits to apply. */

	if (fsp->is_directory) {
		and_bits = lp_dir_security_mask(snum);
		or_bits = lp_force_dir_security_mode(snum);
	} else {
		and_bits = lp_security_mask(snum);
		or_bits = lp_force_security_mode(snum);
	}

	*posix_perms = (((*posix_perms) & and_bits)|or_bits);

	DEBUG(10,("convert_canon_ace_to_posix_perms: converted u=%o,g=%o,w=%o to perm=0%o for file %s.\n",
		(int)owner_ace->perms, (int)group_ace->perms, (int)other_ace->perms, (int)*posix_perms,
		fsp->fsp_name ));

	return True;
}

static int nt_ace_comp( SEC_ACE *a1, SEC_ACE *a2)
{
	if (a1->type == a2->type)
		return 0;

	if (a1->type == SEC_ACE_TYPE_ACCESS_DENIED && a2->type == SEC_ACE_TYPE_ACCESS_ALLOWED)
		return -1;
	return 1;
}

/****************************************************************************
 Reply to query a security descriptor from an fsp. If it succeeds it allocates
 the space for the return elements and returns the size needed to return the
 security descriptor. This should be the only external function needed for
 the UNIX style get ACL.
****************************************************************************/

size_t get_nt_acl(files_struct *fsp, SEC_DESC **ppdesc)
{
	SMB_STRUCT_STAT sbuf;
	SEC_ACE *nt_ace_list = NULL;
	DOM_SID owner_sid;
	DOM_SID group_sid;
	size_t sd_size = 0;
	SEC_ACL *psa = NULL;
	size_t num_acls = 0;
	size_t num_dir_acls = 0;
	size_t num_aces = 0;
	SMB_ACL_T posix_acl = NULL;
	SMB_ACL_T dir_acl = NULL;
	canon_ace *file_ace = NULL;
	canon_ace *dir_ace = NULL;
 
	*ppdesc = NULL;

	DEBUG(10,("get_nt_acl: called for file %s\n", fsp->fsp_name ));

	if(fsp->is_directory || fsp->fd == -1) {

		/* Get the stat struct for the owner info. */
		if(vfs_stat(fsp->conn,fsp->fsp_name, &sbuf) != 0) {
			return 0;
		}
		/*
		 * Get the ACL from the path.
		 */

		posix_acl = sys_acl_get_file(fsp->fsp_name, SMB_ACL_TYPE_ACCESS);

		/*
		 * If it's a directory get the default POSIX ACL.
		 */

		if(fsp->is_directory)
			dir_acl = sys_acl_get_file(fsp->fsp_name, SMB_ACL_TYPE_DEFAULT);

	} else {

		/* Get the stat struct for the owner info. */
		if(vfs_fstat(fsp,fsp->fd,&sbuf) != 0) {
			return 0;
		}
		/*
		 * Get the ACL from the fd.
		 */
		posix_acl = sys_acl_get_fd(fsp->fd);
	}

	DEBUG(5,("get_nt_acl : file ACL %s, directory ACL %s\n",
			posix_acl ? "present" :  "absent",
			dir_acl ? "present" :  "absent" ));

	/*
	 * Get the owner, group and world SIDs.
	 */

	create_file_sids(&sbuf, &owner_sid, &group_sid);

	/* Create the canon_ace lists. */
	file_ace = canonicalise_acl( fsp, posix_acl, &sbuf,  &owner_sid, &group_sid);
	num_acls = count_canon_ace_list(file_ace);

	/* We must have *some* ACLS. */

	if (num_acls == 0) {
		DEBUG(0,("get_nt_acl : No ACLs on file (%s) !\n", fsp->fsp_name ));
		return 0;
	}

	if (fsp->is_directory) { 
		/*
		 * If we have to fake a default ACL then this is the mode to use.
		 */
		sbuf.st_mode = unix_mode( fsp->conn, FILE_ATTRIBUTE_ARCHIVE, fsp->fsp_name);

		dir_ace = canonicalise_acl(fsp, dir_acl, &sbuf, &owner_sid, &group_sid);
		num_dir_acls = count_canon_ace_list(dir_ace);
	}

	/* Allocate the ace list. */
	if ((nt_ace_list = (SEC_ACE *)malloc((num_acls + num_dir_acls)* sizeof(SEC_ACE))) == NULL) {
		DEBUG(0,("get_nt_acl: Unable to malloc space for nt_ace_list.\n"));
		goto done;
	}

	memset(nt_ace_list, '\0', (num_acls + num_dir_acls) * sizeof(SEC_ACE) );

	/*
	 * Create the NT ACE list from the canonical ace lists.
	 */

	{
		canon_ace *ace;
		int nt_acl_type;
		int i;

		ace = file_ace;

		for (i = 0; i < num_acls; i++, ace = ace->next) {
			SEC_ACCESS acc = map_canon_ace_perms(&nt_acl_type, &owner_sid, ace );
			init_sec_ace(&nt_ace_list[num_aces++], &ace->trustee, nt_acl_type, acc, 0);
		}

		ace = dir_ace;

		for (i = 0; i < num_dir_acls; i++, ace = ace->next) {
			SEC_ACCESS acc = map_canon_ace_perms(&nt_acl_type, &owner_sid, ace );
			init_sec_ace(&nt_ace_list[num_aces++], &ace->trustee, nt_acl_type, acc, 
					SEC_ACE_FLAG_OBJECT_INHERIT|SEC_ACE_FLAG_CONTAINER_INHERIT|SEC_ACE_FLAG_INHERIT_ONLY);
		}

		/*
		 * Sort to force deny entries to the front.
		 */

		if (num_acls + num_dir_acls)
			qsort( nt_ace_list, num_acls + num_dir_acls, sizeof(nt_ace_list[0]), QSORT_CAST nt_ace_comp);
	}

	if (num_acls) {
		if((psa = make_sec_acl( main_loop_talloc_get(), ACL_REVISION, num_aces, nt_ace_list)) == NULL) {
			DEBUG(0,("get_nt_acl: Unable to malloc space for acl.\n"));
			goto done;
		}
	}

	*ppdesc = make_standard_sec_desc( main_loop_talloc_get(), &owner_sid, &group_sid, psa, &sd_size);

	if(!*ppdesc) {
		DEBUG(0,("get_nt_acl: Unable to malloc space for security descriptor.\n"));
		sd_size = 0;
	}

  done:

	if (posix_acl)	
		sys_acl_free_acl(posix_acl);
	if (dir_acl)
		sys_acl_free_acl(dir_acl);
	free_canon_ace_list(file_ace);
	free_canon_ace_list(dir_ace);
	SAFE_FREE(nt_ace_list);

	return sd_size;
}

/****************************************************************************
 Reply to set a security descriptor on an fsp. security_info_sent is the
 description of the following NT ACL.
 This should be the only external function needed for the UNIX style set ACL.
****************************************************************************/

BOOL set_nt_acl(files_struct *fsp, uint32 security_info_sent, SEC_DESC *psd)
{
	connection_struct *conn = fsp->conn;
	uid_t user = (uid_t)-1;
	gid_t grp = (gid_t)-1;
	SMB_STRUCT_STAT sbuf;  
	DOM_SID file_owner_sid;
	DOM_SID file_grp_sid;
	canon_ace *file_ace_list = NULL;
	canon_ace *dir_ace_list = NULL;
	BOOL acl_perms = False;
	mode_t orig_mode = (mode_t)0;
	uid_t orig_uid;
	gid_t orig_gid;

	DEBUG(10,("set_nt_acl: called for file %s\n", fsp->fsp_name ));

	/*
	 * Get the current state of the file.
	 */

	if(fsp->is_directory || fsp->fd == -1) {
		if(vfs_stat(fsp->conn,fsp->fsp_name, &sbuf) != 0)
			return False;
	} else {
		if(vfs_fstat(fsp,fsp->fd,&sbuf) != 0)
			return False;
	}

	/* Save the original elements we check against. */
	orig_mode = sbuf.st_mode;
	orig_uid = sbuf.st_uid;
	orig_gid = sbuf.st_gid;

	/*
	 * Unpack the user/group/world id's.
	 */

	if (!unpack_nt_owners( &sbuf, &user, &grp, security_info_sent, psd))
		return False;

	/*
	 * Do we need to chown ?
	 */

	if((user != (uid_t)-1 || grp != (uid_t)-1) && (orig_uid != user || orig_gid != grp)) {

		DEBUG(3,("set_nt_acl: chown %s. uid = %u, gid = %u.\n",
				fsp->fsp_name, (unsigned int)user, (unsigned int)grp ));

		if(vfs_chown( fsp->conn, fsp->fsp_name, user, grp) == -1) {
			DEBUG(3,("set_nt_acl: chown %s, %u, %u failed. Error = %s.\n",
				fsp->fsp_name, (unsigned int)user, (unsigned int)grp, strerror(errno) ));
			return False;
		}

		/*
		 * Recheck the current state of the file, which may have changed.
		 * (suid/sgid bits, for instance)
		 */

		if(fsp->is_directory) {
			if(vfs_stat(fsp->conn, fsp->fsp_name, &sbuf) != 0) {
				return False;
			}
		} else {

			int ret;
    
			if(fsp->fd == -1)
				ret = vfs_stat(fsp->conn, fsp->fsp_name, &sbuf);
			else
				ret = vfs_fstat(fsp,fsp->fd,&sbuf);
  
			if(ret != 0)
				return False;
		}

		/* Save the original elements we check against. */
		orig_mode = sbuf.st_mode;
		orig_uid = sbuf.st_uid;
		orig_gid = sbuf.st_gid;
	}

	create_file_sids(&sbuf, &file_owner_sid, &file_grp_sid);

	acl_perms = unpack_canon_ace( fsp, &sbuf, &file_owner_sid, &file_grp_sid,
									&file_ace_list, &dir_ace_list, security_info_sent, psd);

	if ((file_ace_list == NULL) && (dir_ace_list == NULL)) {
		/* W2K traverse DACL set - ignore. */
		return True;
    }

	if (!acl_perms) {
		DEBUG(3,("set_nt_acl: cannot set permissions\n"));
		free_canon_ace_list(file_ace_list);
		free_canon_ace_list(dir_ace_list); 
		return False;
	}

	/*
	 * Only change security if we got a DACL.
	 */

	if((security_info_sent & DACL_SECURITY_INFORMATION) && (psd->dacl != NULL)) {

		BOOL acl_set_support = False;
		BOOL ret = False;

		/*
		 * Try using the POSIX ACL set first. Fall back to chmod if
		 * we have no ACL support on this filesystem.
		 */

		if (acl_perms && file_ace_list) {
			ret = set_canon_ace_list(fsp, file_ace_list, False, &acl_set_support);
			if (acl_set_support && ret == False) {
				DEBUG(3,("set_nt_acl: failed to set file acl on file %s (%s).\n", fsp->fsp_name, strerror(errno) ));
				free_canon_ace_list(file_ace_list);
				free_canon_ace_list(dir_ace_list); 
				return False;
			}
		}

		if (acl_perms && acl_set_support && fsp->is_directory) {
			if (dir_ace_list) {
				if (!set_canon_ace_list(fsp, dir_ace_list, True, &acl_set_support)) {
					DEBUG(3,("set_nt_acl: failed to set default acl on directory %s (%s).\n", fsp->fsp_name, strerror(errno) ));
					free_canon_ace_list(file_ace_list);
					free_canon_ace_list(dir_ace_list); 
					return False;
				}
			} else {

				/*
				 * No default ACL - delete one if it exists.
				 */

				if (sys_acl_delete_def_file(fsp->fsp_name) == -1) {
					DEBUG(3,("set_nt_acl: sys_acl_delete_def_file failed (%s)\n", strerror(errno)));
					free_canon_ace_list(file_ace_list);
					return False;
				}
			}
		}

		/*
		 * If we cannot set using POSIX ACLs we fall back to checking if we need to chmod.
		 */

		if(!acl_set_support && acl_perms) {
			mode_t posix_perms;

			if (!convert_canon_ace_to_posix_perms( fsp, file_ace_list, &posix_perms)) {
				free_canon_ace_list(file_ace_list);
				free_canon_ace_list(dir_ace_list);
				DEBUG(3,("set_nt_acl: failed to convert file acl to posix permissions for file %s.\n",
					fsp->fsp_name ));
				return False;
			}

			if (orig_mode != posix_perms) {

				DEBUG(3,("set_nt_acl: chmod %s. perms = 0%o.\n",
					fsp->fsp_name, (unsigned int)posix_perms ));

				if(conn->vfs_ops.chmod(conn,fsp->fsp_name, posix_perms) == -1) {
					DEBUG(3,("set_nt_acl: chmod %s, 0%o failed. Error = %s.\n",
							fsp->fsp_name, (unsigned int)posix_perms, strerror(errno) ));
					free_canon_ace_list(file_ace_list);
					free_canon_ace_list(dir_ace_list);
					return False;
				}
			}
		}
	}

	free_canon_ace_list(file_ace_list);
	free_canon_ace_list(dir_ace_list); 

	return True;
}

/****************************************************************************
 Do a chmod by setting the ACL USER_OBJ, GROUP_OBJ and OTHER bits in an ACL
 and set the mask to rwx. Needed to preserve complex ACLs set by NT.
****************************************************************************/

static int chmod_acl_internals( SMB_ACL_T posix_acl, mode_t mode)
{
	int entry_id = SMB_ACL_FIRST_ENTRY;
	SMB_ACL_ENTRY_T entry;
	int num_entries = 0;

	while ( sys_acl_get_entry(posix_acl, entry_id, &entry) == 1) {
		SMB_ACL_TAG_T tagtype;
		SMB_ACL_PERMSET_T permset;
		mode_t perms;

		/* get_next... */
		if (entry_id == SMB_ACL_FIRST_ENTRY)
			entry_id = SMB_ACL_NEXT_ENTRY;

		if (sys_acl_get_tag_type(entry, &tagtype) == -1)
			return -1;

		if (sys_acl_get_permset(entry, &permset) == -1)
			return -1;

		num_entries++;

		switch(tagtype) {
			case SMB_ACL_USER_OBJ:
				perms = unix_perms_to_acl_perms(mode, S_IRUSR, S_IWUSR, S_IXUSR);
                break;
			case SMB_ACL_GROUP_OBJ:
				perms = unix_perms_to_acl_perms(mode, S_IRGRP, S_IWGRP, S_IXGRP);
				break;
			case SMB_ACL_MASK:
				perms = S_IRUSR|S_IWUSR|S_IXUSR;
				break;
			case SMB_ACL_OTHER:
				perms = unix_perms_to_acl_perms(mode, S_IROTH, S_IWOTH, S_IXOTH);
				break;
			default:
				continue;
		}

		if (map_acl_perms_to_permset(perms, &permset) == -1)
			return -1;

		if (sys_acl_set_permset(entry, permset) == -1)
			return -1;
	}

	/*
	 * If this is a simple 3 element ACL or no elements then it's a standard
	 * UNIX permission set. Just use chmod...	
	 */

	if ((num_entries == 3) || (num_entries == 0))
		return -1;

	return 0;
}

/****************************************************************************
 Do a chmod by setting the ACL USER_OBJ, GROUP_OBJ and OTHER bits in an ACL
 and set the mask to rwx. Needed to preserve complex ACLs set by NT.
 Note that name is in UNIX character set.
****************************************************************************/

int chmod_acl(const char *name, mode_t mode)
{
	SMB_ACL_T posix_acl = NULL;
	int ret = -1;

	if ((posix_acl = sys_acl_get_file(name, SMB_ACL_TYPE_ACCESS)) == NULL)
		return -1;

	if ((ret = chmod_acl_internals(posix_acl, mode)) == -1)
		goto done;

	ret = sys_acl_set_file(name, SMB_ACL_TYPE_ACCESS, posix_acl);

  done:

	sys_acl_free_acl(posix_acl);
	return ret;
}

/****************************************************************************
 Do an fchmod by setting the ACL USER_OBJ, GROUP_OBJ and OTHER bits in an ACL
 and set the mask to rwx. Needed to preserve complex ACLs set by NT.
****************************************************************************/

int fchmod_acl(int fd, mode_t mode)
{
	SMB_ACL_T posix_acl = NULL;
	int ret = -1;

	if ((posix_acl = sys_acl_get_fd(fd)) == NULL)
		return -1;

	if ((ret = chmod_acl_internals(posix_acl, mode)) == -1)
		goto done;

	ret = sys_acl_set_fd(fd, posix_acl);

  done:

	sys_acl_free_acl(posix_acl);
	return ret;
}