summaryrefslogtreecommitdiffstats
path: root/net/ipv4/cipso_ipv4.c
blob: 62d5f99760aacd03b006d6256151ed530896e11b (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
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * CIPSO - Commercial IP Security Option
 *
 * This is an implementation of the CIPSO 2.2 protocol as specified in
 * draft-ietf-cipso-ipsecurity-01.txt with additional tag types as found in
 * FIPS-188.  While CIPSO never became a full IETF RFC standard many vendors
 * have chosen to adopt the protocol and over the years it has become a
 * de-facto standard for labeled networking.
 *
 * The CIPSO draft specification can be found in the kernel's Documentation
 * directory as well as the following URL:
 *   https://tools.ietf.org/id/draft-ietf-cipso-ipsecurity-01.txt
 * The FIPS-188 specification can be found at the following URL:
 *   https://www.itl.nist.gov/fipspubs/fip188.htm
 *
 * Author: Paul Moore <paul.moore@hp.com>
 */

/*
 * (c) Copyright Hewlett-Packard Development Company, L.P., 2006, 2008
 */

#include <linux/init.h>
#include <linux/types.h>
#include <linux/rcupdate.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/jhash.h>
#include <linux/audit.h>
#include <linux/slab.h>
#include <net/ip.h>
#include <net/icmp.h>
#include <net/tcp.h>
#include <net/netlabel.h>
#include <net/cipso_ipv4.h>
#include <linux/atomic.h>
#include <linux/bug.h>
#include <asm/unaligned.h>

/* List of available DOI definitions */
/* XXX - This currently assumes a minimal number of different DOIs in use,
 * if in practice there are a lot of different DOIs this list should
 * probably be turned into a hash table or something similar so we
 * can do quick lookups. */
static DEFINE_SPINLOCK(cipso_v4_doi_list_lock);
static LIST_HEAD(cipso_v4_doi_list);

/* Label mapping cache */
int cipso_v4_cache_enabled = 1;
int cipso_v4_cache_bucketsize = 10;
#define CIPSO_V4_CACHE_BUCKETBITS     7
#define CIPSO_V4_CACHE_BUCKETS        (1 << CIPSO_V4_CACHE_BUCKETBITS)
#define CIPSO_V4_CACHE_REORDERLIMIT   10
struct cipso_v4_map_cache_bkt {
	spinlock_t lock;
	u32 size;
	struct list_head list;
};

struct cipso_v4_map_cache_entry {
	u32 hash;
	unsigned char *key;
	size_t key_len;

	struct netlbl_lsm_cache *lsm_data;

	u32 activity;
	struct list_head list;
};

static struct cipso_v4_map_cache_bkt *cipso_v4_cache;

/* Restricted bitmap (tag #1) flags */
int cipso_v4_rbm_optfmt;
int cipso_v4_rbm_strictvalid = 1;

/*
 * Protocol Constants
 */

/* Maximum size of the CIPSO IP option, derived from the fact that the maximum
 * IPv4 header size is 60 bytes and the base IPv4 header is 20 bytes long. */
#define CIPSO_V4_OPT_LEN_MAX          40

/* Length of the base CIPSO option, this includes the option type (1 byte), the
 * option length (1 byte), and the DOI (4 bytes). */
#define CIPSO_V4_HDR_LEN              6

/* Base length of the restrictive category bitmap tag (tag #1). */
#define CIPSO_V4_TAG_RBM_BLEN         4

/* Base length of the enumerated category tag (tag #2). */
#define CIPSO_V4_TAG_ENUM_BLEN        4

/* Base length of the ranged categories bitmap tag (tag #5). */
#define CIPSO_V4_TAG_RNG_BLEN         4
/* The maximum number of category ranges permitted in the ranged category tag
 * (tag #5).  You may note that the IETF draft states that the maximum number
 * of category ranges is 7, but if the low end of the last category range is
 * zero then it is possible to fit 8 category ranges because the zero should
 * be omitted. */
#define CIPSO_V4_TAG_RNG_CAT_MAX      8

/* Base length of the local tag (non-standard tag).
 *  Tag definition (may change between kernel versions)
 *
 * 0          8          16         24         32
 * +----------+----------+----------+----------+
 * | 10000000 | 00000110 | 32-bit secid value  |
 * +----------+----------+----------+----------+
 * | in (host byte order)|
 * +----------+----------+
 *
 */
#define CIPSO_V4_TAG_LOC_BLEN         6

/*
 * Helper Functions
 */

/**
 * cipso_v4_cache_entry_free - Frees a cache entry
 * @entry: the entry to free
 *
 * Description:
 * This function frees the memory associated with a cache entry including the
 * LSM cache data if there are no longer any users, i.e. reference count == 0.
 *
 */
static void cipso_v4_cache_entry_free(struct cipso_v4_map_cache_entry *entry)
{
	if (entry->lsm_data)
		netlbl_secattr_cache_free(entry->lsm_data);
	kfree(entry->key);
	kfree(entry);
}

/**
 * cipso_v4_map_cache_hash - Hashing function for the CIPSO cache
 * @key: the hash key
 * @key_len: the length of the key in bytes
 *
 * Description:
 * The CIPSO tag hashing function.  Returns a 32-bit hash value.
 *
 */
static u32 cipso_v4_map_cache_hash(const unsigned char *key, u32 key_len)
{
	return jhash(key, key_len, 0);
}

/*
 * Label Mapping Cache Functions
 */

/**
 * cipso_v4_cache_init - Initialize the CIPSO cache
 *
 * Description:
 * Initializes the CIPSO label mapping cache, this function should be called
 * before any of the other functions defined in this file.  Returns zero on
 * success, negative values on error.
 *
 */
static int __init cipso_v4_cache_init(void)
{
	u32 iter;

	cipso_v4_cache = kcalloc(CIPSO_V4_CACHE_BUCKETS,
				 sizeof(struct cipso_v4_map_cache_bkt),
				 GFP_KERNEL);
	if (!cipso_v4_cache)
		return -ENOMEM;

	for (iter = 0; iter < CIPSO_V4_CACHE_BUCKETS; iter++) {
		spin_lock_init(&cipso_v4_cache[iter].lock);
		cipso_v4_cache[iter].size = 0;
		INIT_LIST_HEAD(&cipso_v4_cache[iter].list);
	}

	return 0;
}

/**
 * cipso_v4_cache_invalidate - Invalidates the current CIPSO cache
 *
 * Description:
 * Invalidates and frees any entries in the CIPSO cache.
 *
 */
void cipso_v4_cache_invalidate(void)
{
	struct cipso_v4_map_cache_entry *entry, *tmp_entry;
	u32 iter;

	for (iter = 0; iter < CIPSO_V4_CACHE_BUCKETS; iter++) {
		spin_lock_bh(&cipso_v4_cache[iter].lock);
		list_for_each_entry_safe(entry,
					 tmp_entry,
					 &cipso_v4_cache[iter].list, list) {
			list_del(&entry->list);
			cipso_v4_cache_entry_free(entry);
		}
		cipso_v4_cache[iter].size = 0;
		spin_unlock_bh(&cipso_v4_cache[iter].lock);
	}
}

/**
 * cipso_v4_cache_check - Check the CIPSO cache for a label mapping
 * @key: the buffer to check
 * @key_len: buffer length in bytes
 * @secattr: the security attribute struct to use
 *
 * Description:
 * This function checks the cache to see if a label mapping already exists for
 * the given key.  If there is a match then the cache is adjusted and the
 * @secattr struct is populated with the correct LSM security attributes.  The
 * cache is adjusted in the following manner if the entry is not already the
 * first in the cache bucket:
 *
 *  1. The cache entry's activity counter is incremented
 *  2. The previous (higher ranking) entry's activity counter is decremented
 *  3. If the difference between the two activity counters is geater than
 *     CIPSO_V4_CACHE_REORDERLIMIT the two entries are swapped
 *
 * Returns zero on success, -ENOENT for a cache miss, and other negative values
 * on error.
 *
 */
static int cipso_v4_cache_check(const unsigned char *key,
				u32 key_len,
				struct netlbl_lsm_secattr *secattr)
{
	u32 bkt;
	struct cipso_v4_map_cache_entry *entry;
	struct cipso_v4_map_cache_entry *prev_entry = NULL;
	u32 hash;

	if (!cipso_v4_cache_enabled)
		return -ENOENT;

	hash = cipso_v4_map_cache_hash(key, key_len);
	bkt = hash & (CIPSO_V4_CACHE_BUCKETS - 1);
	spin_lock_bh(&cipso_v4_cache[bkt].lock);
	list_for_each_entry(entry, &cipso_v4_cache[bkt].list, list) {
		if (entry->hash == hash &&
		    entry->key_len == key_len &&
		    memcmp(entry->key, key, key_len) == 0) {
			entry->activity += 1;
			refcount_inc(&entry->lsm_data->refcount);
			secattr->cache = entry->lsm_data;
			secattr->flags |= NETLBL_SECATTR_CACHE;
			secattr->type = NETLBL_NLTYPE_CIPSOV4;
			if (!prev_entry) {
				spin_unlock_bh(&cipso_v4_cache[bkt].lock);
				return 0;
			}

			if (prev_entry->activity > 0)
				prev_entry->activity -= 1;
			if (entry->activity > prev_entry->activity &&
			    entry->activity - prev_entry->activity >
			    CIPSO_V4_CACHE_REORDERLIMIT) {
				__list_del(entry->list.prev, entry->list.next);
				__list_add(&entry->list,
					   prev_entry->list.prev,
					   &prev_entry->list);
			}

			spin_unlock_bh(&cipso_v4_cache[bkt].lock);
			return 0;
		}
		prev_entry = entry;
	}
	spin_unlock_bh(&cipso_v4_cache[bkt].lock);

	return -ENOENT;
}

/**
 * cipso_v4_cache_add - Add an entry to the CIPSO cache
 * @cipso_ptr: pointer to CIPSO IP option
 * @secattr: the packet's security attributes
 *
 * Description:
 * Add a new entry into the CIPSO label mapping cache.  Add the new entry to
 * head of the cache bucket's list, if the cache bucket is out of room remove
 * the last entry in the list first.  It is important to note that there is
 * currently no checking for duplicate keys.  Returns zero on success,
 * negative values on failure.
 *
 */
int cipso_v4_cache_add(const unsigned char *cipso_ptr,
		       const struct netlbl_lsm_secattr *secattr)
{
	int ret_val = -EPERM;
	u32 bkt;
	struct cipso_v4_map_cache_entry *entry = NULL;
	struct cipso_v4_map_cache_entry *old_entry = NULL;
	u32 cipso_ptr_len;

	if (!cipso_v4_cache_enabled || cipso_v4_cache_bucketsize <= 0)
		return 0;

	cipso_ptr_len = cipso_ptr[1];

	entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
	if (!entry)
		return -ENOMEM;
	entry->key = kmemdup(cipso_ptr, cipso_ptr_len, GFP_ATOMIC);
	if (!entry->key) {
		ret_val = -ENOMEM;
		goto cache_add_failure;
	}
	entry->key_len = cipso_ptr_len;
	entry->hash = cipso_v4_map_cache_hash(cipso_ptr, cipso_ptr_len);
	refcount_inc(&secattr->cache->refcount);
	entry->lsm_data = secattr->cache;

	bkt = entry->hash & (CIPSO_V4_CACHE_BUCKETS - 1);
	spin_lock_bh(&cipso_v4_cache[bkt].lock);
	if (cipso_v4_cache[bkt].size < cipso_v4_cache_bucketsize) {
		list_add(&entry->list, &cipso_v4_cache[bkt].list);
		cipso_v4_cache[bkt].size += 1;
	} else {
		old_entry = list_entry(cipso_v4_cache[bkt].list.prev,
				       struct cipso_v4_map_cache_entry, list);
		list_del(&old_entry->list);
		list_add(&entry->list, &cipso_v4_cache[bkt].list);
		cipso_v4_cache_entry_free(old_entry);
	}
	spin_unlock_bh(&cipso_v4_cache[bkt].lock);

	return 0;

cache_add_failure:
	if (entry)
		cipso_v4_cache_entry_free(entry);
	return ret_val;
}

/*
 * DOI List Functions
 */

/**
 * cipso_v4_doi_search - Searches for a DOI definition
 * @doi: the DOI to search for
 *
 * Description:
 * Search the DOI definition list for a DOI definition with a DOI value that
 * matches @doi.  The caller is responsible for calling rcu_read_[un]lock().
 * Returns a pointer to the DOI definition on success and NULL on failure.
 */
static struct cipso_v4_doi *cipso_v4_doi_search(u32 doi)
{
	struct cipso_v4_doi *iter;

	list_for_each_entry_rcu(iter, &cipso_v4_doi_list, list)
		if (iter->doi == doi && refcount_read(&iter->refcount))
			return iter;
	return NULL;
}

/**
 * cipso_v4_doi_add - Add a new DOI to the CIPSO protocol engine
 * @doi_def: the DOI structure
 * @audit_info: NetLabel audit information
 *
 * Description:
 * The caller defines a new DOI for use by the CIPSO engine and calls this
 * function to add it to the list of acceptable domains.  The caller must
 * ensure that the mapping table specified in @doi_def->map meets all of the
 * requirements of the mapping type (see cipso_ipv4.h for details).  Returns
 * zero on success and non-zero on failure.
 *
 */
int cipso_v4_doi_add(struct cipso_v4_doi *doi_def,
		     struct netlbl_audit *audit_info)
{
	int ret_val = -EINVAL;
	u32 iter;
	u32 doi;
	u32 doi_type;
	struct audit_buffer *audit_buf;

	doi = doi_def->doi;
	doi_type = doi_def->type;

	if (doi_def->doi == CIPSO_V4_DOI_UNKNOWN)
		goto doi_add_return;
	for (iter = 0; iter < CIPSO_V4_TAG_MAXCNT; iter++) {
		switch (doi_def->tags[iter]) {
		case CIPSO_V4_TAG_RBITMAP:
			break;
		case CIPSO_V4_TAG_RANGE:
		case CIPSO_V4_TAG_ENUM:
			if (doi_def->type != CIPSO_V4_MAP_PASS)
				goto doi_add_return;
			break;
		case CIPSO_V4_TAG_LOCAL:
			if (doi_def->type != CIPSO_V4_MAP_LOCAL)
				goto doi_add_return;
			break;
		case CIPSO_V4_TAG_INVALID:
			if (iter == 0)
				goto doi_add_return;
			break;
		default:
			goto doi_add_return;
		}
	}

	refcount_set(&doi_def->refcount, 1);

	spin_lock(&cipso_v4_doi_list_lock);
	if (cipso_v4_doi_search(doi_def->doi)) {
		spin_unlock(&cipso_v4_doi_list_lock);
		ret_val = -EEXIST;
		goto doi_add_return;
	}
	list_add_tail_rcu(&doi_def->list, &cipso_v4_doi_list);
	spin_unlock(&cipso_v4_doi_list_lock);
	ret_val = 0;

doi_add_return:
	audit_buf = netlbl_audit_start(AUDIT_MAC_CIPSOV4_ADD, audit_info);
	if (audit_buf) {
		const char *type_str;
		switch (doi_type) {
		case CIPSO_V4_MAP_TRANS:
			type_str = "trans";
			break;
		case CIPSO_V4_MAP_PASS:
			type_str = "pass";
			break;
		case CIPSO_V4_MAP_LOCAL:
			type_str = "local";
			break;
		default:
			type_str = "(unknown)";
		}
		audit_log_format(audit_buf,
				 " cipso_doi=%u cipso_type=%s res=%u",
				 doi, type_str, ret_val == 0 ? 1 : 0);
		audit_log_end(audit_buf);
	}

	return ret_val;
}

/**
 * cipso_v4_doi_free - Frees a DOI definition
 * @doi_def: the DOI definition
 *
 * Description:
 * This function frees all of the memory associated with a DOI definition.
 *
 */
void cipso_v4_doi_free(struct cipso_v4_doi *doi_def)
{
	if (!doi_def)
		return;

	switch (doi_def->type) {
	case CIPSO_V4_MAP_TRANS:
		kfree(doi_def->map.std->lvl.cipso);
		kfree(doi_def->map.std->lvl.local);
		kfree(doi_def->map.std->cat.cipso);
		kfree(doi_def->map.std->cat.local);
		kfree(doi_def->map.std);
		break;
	}
	kfree(doi_def);
}

/**
 * cipso_v4_doi_free_rcu - Frees a DOI definition via the RCU pointer
 * @entry: the entry's RCU field
 *
 * Description:
 * This function is designed to be used as a callback to the call_rcu()
 * function so that the memory allocated to the DOI definition can be released
 * safely.
 *
 */
static void cipso_v4_doi_free_rcu(struct rcu_head *entry)
{
	struct cipso_v4_doi *doi_def;

	doi_def = container_of(entry, struct cipso_v4_doi, rcu);
	cipso_v4_doi_free(doi_def);
}

/**
 * cipso_v4_doi_remove - Remove an existing DOI from the CIPSO protocol engine
 * @doi: the DOI value
 * @audit_info: NetLabel audit information
 *
 * Description:
 * Removes a DOI definition from the CIPSO engine.  The NetLabel routines will
 * be called to release their own LSM domain mappings as well as our own
 * domain list.  Returns zero on success and negative values on failure.
 *
 */
int cipso_v4_doi_remove(u32 doi, struct netlbl_audit *audit_info)
{
	int ret_val;
	struct cipso_v4_doi *doi_def;
	struct audit_buffer *audit_buf;

	spin_lock(&cipso_v4_doi_list_lock);
	doi_def = cipso_v4_doi_search(doi);
	if (!doi_def) {
		spin_unlock(&cipso_v4_doi_list_lock);
		ret_val = -ENOENT;
		goto doi_remove_return;
	}
	list_del_rcu(&doi_def->list);
	spin_unlock(&cipso_v4_doi_list_lock);

	cipso_v4_doi_putdef(doi_def);
	ret_val = 0;

doi_remove_return:
	audit_buf = netlbl_audit_start(AUDIT_MAC_CIPSOV4_DEL, audit_info);
	if (audit_buf) {
		audit_log_format(audit_buf,
				 " cipso_doi=%u res=%u",
				 doi, ret_val == 0 ? 1 : 0);
		audit_log_end(audit_buf);
	}

	return ret_val;
}

/**
 * cipso_v4_doi_getdef - Returns a reference to a valid DOI definition
 * @doi: the DOI value
 *
 * Description:
 * Searches for a valid DOI definition and if one is found it is returned to
 * the caller.  Otherwise NULL is returned.  The caller must ensure that
 * rcu_read_lock() is held while accessing the returned definition and the DOI
 * definition reference count is decremented when the caller is done.
 *
 */
struct cipso_v4_doi *cipso_v4_doi_getdef(u32 doi)
{
	struct cipso_v4_doi *doi_def;

	rcu_read_lock();
	doi_def = cipso_v4_doi_search(doi);
	if (!doi_def)
		goto doi_getdef_return;
	if (!refcount_inc_not_zero(&doi_def->refcount))
		doi_def = NULL;

doi_getdef_return:
	rcu_read_unlock();
	return doi_def;
}

/**
 * cipso_v4_doi_putdef - Releases a reference for the given DOI definition
 * @doi_def: the DOI definition
 *
 * Description:
 * Releases a DOI definition reference obtained from cipso_v4_doi_getdef().
 *
 */
void cipso_v4_doi_putdef(struct cipso_v4_doi *doi_def)
{
	if (!doi_def)
		return;

	if (!refcount_dec_and_test(&doi_def->refcount))
		return;

	cipso_v4_cache_invalidate();
	call_rcu(&doi_def->rcu, cipso_v4_doi_free_rcu);
}

/**
 * cipso_v4_doi_walk - Iterate through the DOI definitions
 * @skip_cnt: skip past this number of DOI definitions, updated
 * @callback: callback for each DOI definition
 * @cb_arg: argument for the callback function
 *
 * Description:
 * Iterate over the DOI definition list, skipping the first @skip_cnt entries.
 * For each entry call @callback, if @callback returns a negative value stop
 * 'walking' through the list and return.  Updates the value in @skip_cnt upon
 * return.  Returns zero on success, negative values on failure.
 *
 */
int cipso_v4_doi_walk(u32 *skip_cnt,
		     int (*callback) (struct cipso_v4_doi *doi_def, void *arg),
		     void *cb_arg)
{
	int ret_val = -ENOENT;
	u32 doi_cnt = 0;
	struct cipso_v4_doi *iter_doi;

	rcu_read_lock();
	list_for_each_entry_rcu(iter_doi, &cipso_v4_doi_list, list)
		if (refcount_read(&iter_doi->refcount) > 0) {
			if (doi_cnt++ < *skip_cnt)
				continue;
			ret_val = callback(iter_doi, cb_arg);
			if (ret_val < 0) {
				doi_cnt--;
				goto doi_walk_return;
			}
		}

doi_walk_return:
	rcu_read_unlock();
	*skip_cnt = doi_cnt;
	return ret_val;
}

/*
 * Label Mapping Functions
 */

/**
 * cipso_v4_map_lvl_valid - Checks to see if the given level is understood
 * @doi_def: the DOI definition
 * @level: the level to check
 *
 * Description:
 * Checks the given level against the given DOI definition and returns a
 * negative value if the level does not have a valid mapping and a zero value
 * if the level is defined by the DOI.
 *
 */
static int cipso_v4_map_lvl_valid(const struct cipso_v4_doi *doi_def, u8 level)
{
	switch (doi_def->type) {
	case CIPSO_V4_MAP_PASS:
		return 0;
	case CIPSO_V4_MAP_TRANS:
		if ((level < doi_def->map.std->lvl.cipso_size) &&
		    (doi_def->map.std->lvl.cipso[level] < CIPSO_V4_INV_LVL))
			return 0;
		break;
	}

	return -EFAULT;
}

/**
 * cipso_v4_map_lvl_hton - Perform a level mapping from the host to the network
 * @doi_def: the DOI definition
 * @host_lvl: the host MLS level
 * @net_lvl: the network/CIPSO MLS level
 *
 * Description:
 * Perform a label mapping to translate a local MLS level to the correct
 * CIPSO level using the given DOI definition.  Returns zero on success,
 * negative values otherwise.
 *
 */
static int cipso_v4_map_lvl_hton(const struct cipso_v4_doi *doi_def,
				 u32 host_lvl,
				 u32 *net_lvl)
{
	switch (doi_def->type) {
	case CIPSO_V4_MAP_PASS:
		*net_lvl = host_lvl;
		return 0;
	case CIPSO_V4_MAP_TRANS:
		if (host_lvl < doi_def->map.std->lvl.local_size &&
		    doi_def->map.std->lvl.local[host_lvl] < CIPSO_V4_INV_LVL) {
			*net_lvl = doi_def->map.std->lvl.local[host_lvl];
			return 0;
		}
		return -EPERM;
	}

	return -EINVAL;
}

/**
 * cipso_v4_map_lvl_ntoh - Perform a level mapping from the network to the host
 * @doi_def: the DOI definition
 * @net_lvl: the network/CIPSO MLS level
 * @host_lvl: the host MLS level
 *
 * Description:
 * Perform a label mapping to translate a CIPSO level to the correct local MLS
 * level using the given DOI definition.  Returns zero on success, negative
 * values otherwise.
 *
 */
static int cipso_v4_map_lvl_ntoh(const struct cipso_v4_doi *doi_def,
				 u32 net_lvl,
				 u32 *host_lvl)
{
	struct cipso_v4_std_map_tbl *map_tbl;

	switch (doi_def->type) {
	case CIPSO_V4_MAP_PASS:
		*host_lvl = net_lvl;
		return 0;
	case CIPSO_V4_MAP_TRANS:
		map_tbl = doi_def->map.std;
		if (net_lvl < map_tbl->lvl.cipso_size &&
		    map_tbl->lvl.cipso[net_lvl] < CIPSO_V4_INV_LVL) {
			*host_lvl = doi_def->map.std->lvl.cipso[net_lvl];
			return 0;
		}
		return -EPERM;
	}

	return -EINVAL;
}

/**
 * cipso_v4_map_cat_rbm_valid - Checks to see if the category bitmap is valid
 * @doi_def: the DOI definition
 * @bitmap: category bitmap
 * @bitmap_len: bitmap length in bytes
 *
 * Description:
 * Checks the given category bitmap against the given DOI definition and
 * returns a negative value if any of the categories in the bitmap do not have
 * a valid mapping and a zero value if all of the categories are valid.
 *
 */
static int cipso_v4_map_cat_rbm_valid(const struct cipso_v4_doi *doi_def,
				      const unsigned char *bitmap,
				      u32 bitmap_len)
{
	int cat = -1;
	u32 bitmap_len_bits = bitmap_len * 8;
	u32 cipso_cat_size;
	u32 *cipso_array;

	switch (doi_def->type) {
	case CIPSO_V4_MAP_PASS:
		return 0;
	case CIPSO_V4_MAP_TRANS:
		cipso_cat_size = doi_def->map.std->cat.cipso_size;
		cipso_array = doi_def->map.std->cat.cipso;
		for (;;) {
			cat = netlbl_bitmap_walk(bitmap,
						 bitmap_len_bits,
						 cat + 1,
						 1);
			if (cat < 0)
				break;
			if (cat >= cipso_cat_size ||
			    cipso_array[cat] >= CIPSO_V4_INV_CAT)
				return -EFAULT;
		}

		if (cat == -1)
			return 0;
		break;
	}

	return -EFAULT;
}

/**
 * cipso_v4_map_cat_rbm_hton - Perform a category mapping from host to network
 * @doi_def: the DOI definition
 * @secattr: the security attributes
 * @net_cat: the zero'd out category bitmap in network/CIPSO format
 * @net_cat_len: the length of the CIPSO bitmap in bytes
 *
 * Description:
 * Perform a label mapping to translate a local MLS category bitmap to the
 * correct CIPSO bitmap using the given DOI definition.  Returns the minimum
 * size in bytes of the network bitmap on success, negative values otherwise.
 *
 */
static int cipso_v4_map_cat_rbm_hton(const struct cipso_v4_doi *doi_def,
				     const struct netlbl_lsm_secattr *secattr,
				     unsigned char *net_cat,
				     u32 net_cat_len)
{
	int host_spot = -1;
	u32 net_spot = CIPSO_V4_INV_CAT;
	u32 net_spot_max = 0;
	u32 net_clen_bits = net_cat_len * 8;
	u32 host_cat_size = 0;
	u32 *host_cat_array = NULL;

	if (doi_def->type == CIPSO_V4_MAP_TRANS) {
		host_cat_size = doi_def->map.std->cat.local_size;
		host_cat_array = doi_def->map.std->cat.local;
	}

	for (;;) {
		host_spot = netlbl_catmap_walk(secattr->attr.mls.cat,
					       host_spot + 1);
		if (host_spot < 0)
			break;

		switch (doi_def->type) {
		case CIPSO_V4_MAP_PASS:
			net_spot = host_spot;
			break;
		case CIPSO_V4_MAP_TRANS:
			if (host_spot >= host_cat_size)
				return -EPERM;
			net_spot = host_cat_array[host_spot];
			if (net_spot >= CIPSO_V4_INV_CAT)
				return -EPERM;
			break;
		}
		if (net_spot >= net_clen_bits)
			return -ENOSPC;
		netlbl_bitmap_setbit(net_cat, net_spot, 1);

		if (net_spot > net_spot_max)
			net_spot_max = net_spot;
	}

	if (++net_spot_max % 8)
		return net_spot_max / 8 + 1;
	return net_spot_max / 8;
}

/**
 * cipso_v4_map_cat_rbm_ntoh - Perform a category mapping from network to host
 * @doi_def: the DOI definition
 * @net_cat: the category bitmap in network/CIPSO format
 * @net_cat_len: the length of the CIPSO bitmap in bytes
 * @secattr: the security attributes
 *
 * Description:
 * Perform a label mapping to translate a CIPSO bitmap to the correct local
 * MLS category bitmap using the given DOI definition.  Returns zero on
 * success, negative values on failure.
 *
 */
static int cipso_v4_map_cat_rbm_ntoh(const struct cipso_v4_doi *doi_def,
				     const unsigned char *net_cat,
				     u32 net_cat_len,
				     struct netlbl_lsm_secattr *secattr)
{
	int ret_val;
	int net_spot = -1;
	u32 host_spot = CIPSO_V4_INV_CAT;
	u32 net_clen_bits = net_cat_len * 8;
	u32 net_cat_size = 0;
	u32 *net_cat_array = NULL;

	if (doi_def->type == CIPSO_V4_MAP_TRANS) {
		net_cat_size = doi_def->map.std->cat.cipso_size;
		net_cat_array = doi_def->map.std->cat.cipso;
	}

	for (;;) {
		net_spot = netlbl_bitmap_walk(net_cat,
					      net_clen_bits,
					      net_spot + 1,
					      1);
		if (net_spot < 0) {
			if (net_spot == -2)
				return -EFAULT;
			return 0;
		}

		switch (doi_def->type) {
		case CIPSO_V4_MAP_PASS:
			host_spot = net_spot;
			break;
		case CIPSO_V4_MAP_TRANS:
			if (net_spot >= net_cat_size)
				return -EPERM;
			host_spot = net_cat_array[net_spot];
			if (host_spot >= CIPSO_V4_INV_CAT)
				return -EPERM;
			break;
		}
		ret_val = netlbl_catmap_setbit(&secattr->attr.mls.cat,
						       host_spot,
						       GFP_ATOMIC);
		if (ret_val != 0)
			return ret_val;
	}

	return -EINVAL;
}

/**
 * cipso_v4_map_cat_enum_valid - Checks to see if the categories are valid
 * @doi_def: the DOI definition
 * @enumcat: category list
 * @enumcat_len: length of the category list in bytes
 *
 * Description:
 * Checks the given categories against the given DOI definition and returns a
 * negative value if any of the categories do not have a valid mapping and a
 * zero value if all of the categories are valid.
 *
 */
static int cipso_v4_map_cat_enum_valid(const struct cipso_v4_doi *doi_def,
				       const unsigned char *enumcat,
				       u32 enumcat_len)
{
	u16 cat;
	int cat_prev = -1;
	u32 iter;

	if (doi_def->type != CIPSO_V4_MAP_PASS || enumcat_len & 0x01)
		return -EFAULT;

	for (iter = 0; iter < enumcat_len; iter += 2) {
		cat = get_unaligned_be16(&enumcat[iter]);
		if (cat <= cat_prev)
			return -EFAULT;
		cat_prev = cat;
	}

	return 0;
}

/**
 * cipso_v4_map_cat_enum_hton - Perform a category mapping from host to network
 * @doi_def: the DOI definition
 * @secattr: the security attributes
 * @net_cat: the zero'd out category list in network/CIPSO format
 * @net_cat_len: the length of the CIPSO category list in bytes
 *
 * Description:
 * Perform a label mapping to translate a local MLS category bitmap to the
 * correct CIPSO category list using the given DOI definition.   Returns the
 * size in bytes of the network category bitmap on success, negative values
 * otherwise.
 *
 */
static int cipso_v4_map_cat_enum_hton(const struct cipso_v4_doi *doi_def,
				      const struct netlbl_lsm_secattr *secattr,
				      unsigned char *net_cat,
				      u32 net_cat_len)
{
	int cat = -1;
	u32 cat_iter = 0;

	for (;;) {
		cat = netlbl_catmap_walk(secattr->attr.mls.cat, cat + 1);
		if (cat < 0)
			break;
		if ((cat_iter + 2) > net_cat_len)
			return -ENOSPC;

		*((__be16 *)&net_cat[cat_iter]) = htons(cat);
		cat_iter += 2;
	}

	return cat_iter;
}

/**
 * cipso_v4_map_cat_enum_ntoh - Perform a category mapping from network to host
 * @doi_def: the DOI definition
 * @net_cat: the category list in network/CIPSO format
 * @net_cat_len: the length of the CIPSO bitmap in bytes
 * @secattr: the security attributes
 *
 * Description:
 * Perform a label mapping to translate a CIPSO category list to the correct
 * local MLS category bitmap using the given DOI definition.  Returns zero on
 * success, negative values on failure.
 *
 */
static int cipso_v4_map_cat_enum_ntoh(const struct cipso_v4_doi *doi_def,
				      const unsigned char *net_cat,
				      u32 net_cat_len,
				      struct netlbl_lsm_secattr *secattr)
{
	int ret_val;
	u32 iter;

	for (iter = 0; iter < net_cat_len; iter += 2) {
		ret_val = netlbl_catmap_setbit(&secattr->attr.mls.cat,
					     get_unaligned_be16(&net_cat[iter]),
					     GFP_ATOMIC);
		if (ret_val != 0)
			return ret_val;
	}

	return 0;
}

/**
 * cipso_v4_map_cat_rng_valid - Checks to see if the categories are valid
 * @doi_def: the DOI definition
 * @rngcat: category list
 * @rngcat_len: length of the category list in bytes
 *
 * Description:
 * Checks the given categories against the given DOI definition and returns a
 * negative value if any of the categories do not have a valid mapping and a
 * zero value if all of the categories are valid.
 *
 */
static int cipso_v4_map_cat_rng_valid(const struct cipso_v4_doi *doi_def,
				      const unsigned char *rngcat,
				      u32 rngcat_len)
{
	u16 cat_high;
	u16 cat_low;
	u32 cat_prev = CIPSO_V4_MAX_REM_CATS + 1;
	u32 iter;

	if (doi_def->type != CIPSO_V4_MAP_PASS || rngcat_len & 0x01)
		return -EFAULT;

	for (iter = 0; iter < rngcat_len; iter += 4) {
		cat_high = get_unaligned_be16(&rngcat[iter]);
		if ((iter + 4) <= rngcat_len)
			cat_low = get_unaligned_be16(&rngcat[iter + 2]);
		else
			cat_low = 0;

		if (cat_high > cat_prev)
			return -EFAULT;

		cat_prev = cat_low;
	}

	return 0;
}

/**
 * cipso_v4_map_cat_rng_hton - Perform a category mapping from host to network
 * @doi_def: the DOI definition
 * @secattr: the security attributes
 * @net_cat: the zero'd out category list in network/CIPSO format
 * @net_cat_len: the length of the CIPSO category list in bytes
 *
 * Description:
 * Perform a label mapping to translate a local MLS category bitmap to the
 * correct CIPSO category list using the given DOI definition.   Returns the
 * size in bytes of the network category bitmap on success, negative values
 * otherwise.
 *
 */
static int cipso_v4_map_cat_rng_hton(const struct cipso_v4_doi *doi_def,
				     const struct netlbl_lsm_secattr *secattr,
				     unsigned char *net_cat,
				     u32 net_cat_len)
{
	int iter = -1;
	u16 array[CIPSO_V4_TAG_RNG_CAT_MAX * 2];
	u32 array_cnt = 0;
	u32 cat_size = 0;

	/* make sure we don't overflow the 'array[]' variable */
	if (net_cat_len >
	    (CIPSO_V4_OPT_LEN_MAX - CIPSO_V4_HDR_LEN - CIPSO_V4_TAG_RNG_BLEN))
		return -ENOSPC;

	for (;;) {
		iter = netlbl_catmap_walk(secattr->attr.mls.cat, iter + 1);
		if (iter < 0)
			break;
		cat_size += (iter == 0 ? 0 : sizeof(u16));
		if (cat_size > net_cat_len)
			return -ENOSPC;
		array[array_cnt++] = iter;

		iter = netlbl_catmap_walkrng(secattr->attr.mls.cat, iter);
		if (iter < 0)
			return -EFAULT;
		cat_size += sizeof(u16);
		if (cat_size > net_cat_len)
			return -ENOSPC;
		array[array_cnt++] = iter;
	}

	for (iter = 0; array_cnt > 0;) {
		*((__be16 *)&net_cat[iter]) = htons(array[--array_cnt]);
		iter += 2;
		array_cnt--;
		if (array[array_cnt] != 0) {
			*((__be16 *)&net_cat[iter]) = htons(array[array_cnt]);
			iter += 2;
		}
	}

	return cat_size;
}

/**
 * cipso_v4_map_cat_rng_ntoh - Perform a category mapping from network to host
 * @doi_def: the DOI definition
 * @net_cat: the category list in network/CIPSO format
 * @net_cat_len: the length of the CIPSO bitmap in bytes
 * @secattr: the security attributes
 *
 * Description:
 * Perform a label mapping to translate a CIPSO category list to the correct
 * local MLS category bitmap using the given DOI definition.  Returns zero on
 * success, negative values on failure.
 *
 */
static int cipso_v4_map_cat_rng_ntoh(const struct cipso_v4_doi *doi_def,
				     const unsigned char *net_cat,
				     u32 net_cat_len,
				     struct netlbl_lsm_secattr *secattr)
{
	int ret_val;
	u32 net_iter;
	u16 cat_low;
	u16 cat_high;

	for (net_iter = 0; net_iter < net_cat_len; net_iter += 4) {
		cat_high = get_unaligned_be16(&net_cat[net_iter]);
		if ((net_iter + 4) <= net_cat_len)
			cat_low = get_unaligned_be16(&net_cat[net_iter + 2]);
		else
			cat_low = 0;

		ret_val = netlbl_catmap_setrng(&secattr->attr.mls.cat,
					       cat_low,
					       cat_high,
					       GFP_ATOMIC);
		if (ret_val != 0)
			return ret_val;
	}

	return 0;
}

/*
 * Protocol Handling Functions
 */

/**
 * cipso_v4_gentag_hdr - Generate a CIPSO option header
 * @doi_def: the DOI definition
 * @len: the total tag length in bytes, not including this header
 * @buf: the CIPSO option buffer
 *
 * Description:
 * Write a CIPSO header into the beginning of @buffer.
 *
 */
static void cipso_v4_gentag_hdr(const struct cipso_v4_doi *doi_def,
				unsigned char *buf,
				u32 len)
{
	buf[0] = IPOPT_CIPSO;
	buf[1] = CIPSO_V4_HDR_LEN + len;
	put_unaligned_be32(doi_def->doi, &buf[2]);
}

/**
 * cipso_v4_gentag_rbm - Generate a CIPSO restricted bitmap tag (type #1)
 * @doi_def: the DOI definition
 * @secattr: the security attributes
 * @buffer: the option buffer
 * @buffer_len: length of buffer in bytes
 *
 * Description:
 * Generate a CIPSO option using the restricted bitmap tag, tag type #1.  The
 * actual buffer length may be larger than the indicated size due to
 * translation between host and network category bitmaps.  Returns the size of
 * the tag on success, negative values on failure.
 *
 */
static int cipso_v4_gentag_rbm(const struct cipso_v4_doi *doi_def,
			       const struct netlbl_lsm_secattr *secattr,
			       unsigned char *buffer,
			       u32 buffer_len)
{
	int ret_val;
	u32 tag_len;
	u32 level;

	if ((secattr->flags & NETLBL_SECATTR_MLS_LVL) == 0)
		return -EPERM;

	ret_val = cipso_v4_map_lvl_hton(doi_def,
					secattr->attr.mls.lvl,
					&level);
	if (ret_val != 0)
		return ret_val;

	if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
		ret_val = cipso_v4_map_cat_rbm_hton(doi_def,
						    secattr,
						    &buffer[4],
						    buffer_len - 4);
		if (ret_val < 0)
			return ret_val;

		/* This will send packets using the "optimized" format when
		 * possible as specified in  section 3.4.2.6 of the
		 * CIPSO draft. */
		if (cipso_v4_rbm_optfmt && ret_val > 0 && ret_val <= 10)
			tag_len = 14;
		else
			tag_len = 4 + ret_val;
	} else
		tag_len = 4;

	buffer[0] = CIPSO_V4_TAG_RBITMAP;
	buffer[1] = tag_len;
	buffer[3] = level;

	return tag_len;
}

/**
 * cipso_v4_parsetag_rbm - Parse a CIPSO restricted bitmap tag
 * @doi_def: the DOI definition
 * @tag: the CIPSO tag
 * @secattr: the security attributes
 *
 * Description:
 * Parse a CIPSO restricted bitmap tag (tag type #1) and return the security
 * attributes in @secattr.  Return zero on success, negatives values on
 * failure.
 *
 */
static int cipso_v4_parsetag_rbm(const struct cipso_v4_doi *doi_def,
				 const unsigned char *tag,
				 struct netlbl_lsm_secattr *secattr)
{
	int ret_val;
	u8 tag_len = tag[1];
	u32 level;

	ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level);
	if (ret_val != 0)
		return ret_val;
	secattr->attr.mls.lvl = level;
	secattr->flags |= NETLBL_SECATTR_MLS_LVL;

	if (tag_len > 4) {
		ret_val = cipso_v4_map_cat_rbm_ntoh(doi_def,
						    &tag[4],
						    tag_len - 4,
						    secattr);
		if (ret_val != 0) {
			netlbl_catmap_free(secattr->attr.mls.cat);
			return ret_val;
		}

		if (secattr->attr.mls.cat)
			secattr->flags |= NETLBL_SECATTR_MLS_CAT;
	}

	return 0;
}

/**
 * cipso_v4_gentag_enum - Generate a CIPSO enumerated tag (type #2)
 * @doi_def: the DOI definition
 * @secattr: the security attributes
 * @buffer: the option buffer
 * @buffer_len: length of buffer in bytes
 *
 * Description:
 * Generate a CIPSO option using the enumerated tag, tag type #2.  Returns the
 * size of the tag on success, negative values on failure.
 *
 */
static int cipso_v4_gentag_enum(const struct cipso_v4_doi *doi_def,
				const struct netlbl_lsm_secattr *secattr,
				unsigned char *buffer,
				u32 buffer_len)
{
	int ret_val;
	u32 tag_len;
	u32 level;

	if (!(secattr->flags & NETLBL_SECATTR_MLS_LVL))
		return -EPERM;

	ret_val = cipso_v4_map_lvl_hton(doi_def,
					secattr->attr.mls.lvl,
					&level);
	if (ret_val != 0)
		return ret_val;

	if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
		ret_val = cipso_v4_map_cat_enum_hton(doi_def,
						     secattr,
						     &buffer[4],
						     buffer_len - 4);
		if (ret_val < 0)
			return ret_val;

		tag_len = 4 + ret_val;
	} else
		tag_len = 4;

	buffer[0] = CIPSO_V4_TAG_ENUM;
	buffer[1] = tag_len;
	buffer[3] = level;

	return tag_len;
}

/**
 * cipso_v4_parsetag_enum - Parse a CIPSO enumerated tag
 * @doi_def: the DOI definition
 * @tag: the CIPSO tag
 * @secattr: the security attributes
 *
 * Description:
 * Parse a CIPSO enumerated tag (tag type #2) and return the security
 * attributes in @secattr.  Return zero on success, negatives values on
 * failure.
 *
 */
static int cipso_v4_parsetag_enum(const struct cipso_v4_doi *doi_def,
				  const unsigned char *tag,
				  struct netlbl_lsm_secattr *secattr)
{
	int ret_val;
	u8 tag_len = tag[1];
	u32 level;

	ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level);
	if (ret_val != 0)
		return ret_val;
	secattr->attr.mls.lvl = level;
	secattr->flags |= NETLBL_SECATTR_MLS_LVL;

	if (tag_len > 4) {
		ret_val = cipso_v4_map_cat_enum_ntoh(doi_def,
						     &tag[4],
						     tag_len - 4,
						     secattr);
		if (ret_val != 0) {
			netlbl_catmap_free(secattr->attr.mls.cat);
			return ret_val;
		}

		secattr->flags |= NETLBL_SECATTR_MLS_CAT;
	}

	return 0;
}

/**
 * cipso_v4_gentag_rng - Generate a CIPSO ranged tag (type #5)
 * @doi_def: the DOI definition
 * @secattr: the security attributes
 * @buffer: the option buffer
 * @buffer_len: length of buffer in bytes
 *
 * Description:
 * Generate a CIPSO option using the ranged tag, tag type #5.  Returns the
 * size of the tag on success, negative values on failure.
 *
 */
static int cipso_v4_gentag_rng(const struct cipso_v4_doi *doi_def,
			       const struct netlbl_lsm_secattr *secattr,
			       unsigned char *buffer,
			       u32 buffer_len)
{
	int ret_val;
	u32 tag_len;
	u32 level;

	if (!(secattr->flags & NETLBL_SECATTR_MLS_LVL))
		return -EPERM;

	ret_val = cipso_v4_map_lvl_hton(doi_def,
					secattr->attr.mls.lvl,
					&level);
	if (ret_val != 0)
		return ret_val;

	if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
		ret_val = cipso_v4_map_cat_rng_hton(doi_def,
						    secattr,
						    &buffer[4],
						    buffer_len - 4);
		if (ret_val < 0)
			return ret_val;

		tag_len = 4 + ret_val;
	} else
		tag_len = 4;

	buffer[0] = CIPSO_V4_TAG_RANGE;
	buffer[1] = tag_len;
	buffer[3] = level;

	return tag_len;
}

/**
 * cipso_v4_parsetag_rng - Parse a CIPSO ranged tag
 * @doi_def: the DOI definition
 * @tag: the CIPSO tag
 * @secattr: the security attributes
 *
 * Description:
 * Parse a CIPSO ranged tag (tag type #5) and return the security attributes
 * in @secattr.  Return zero on success, negatives values on failure.
 *
 */
static int cipso_v4_parsetag_rng(const struct cipso_v4_doi *doi_def,
				 const unsigned char *tag,
				 struct netlbl_lsm_secattr *secattr)
{
	int ret_val;
	u8 tag_len = tag[1];
	u32 level;

	ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level);
	if (ret_val != 0)
		return ret_val;
	secattr->attr.mls.lvl = level;
	secattr->flags |= NETLBL_SECATTR_MLS_LVL;

	if (tag_len > 4) {
		ret_val = cipso_v4_map_cat_rng_ntoh(doi_def,
						    &tag[4],
						    tag_len - 4,
						    secattr);
		if (ret_val != 0) {
			netlbl_catmap_free(secattr->attr.mls.cat);
			return ret_val;
		}

		if (secattr->attr.mls.cat)
			secattr->flags |= NETLBL_SECATTR_MLS_CAT;
	}

	return 0;
}

/**
 * cipso_v4_gentag_loc - Generate a CIPSO local tag (non-standard)
 * @doi_def: the DOI definition
 * @secattr: the security attributes
 * @buffer: the option buffer
 * @buffer_len: length of buffer in bytes
 *
 * Description:
 * Generate a CIPSO option using the local tag.  Returns the size of the tag
 * on success, negative values on failure.
 *
 */
static int cipso_v4_gentag_loc(const struct cipso_v4_doi *doi_def,
			       const struct netlbl_lsm_secattr *secattr,
			       unsigned char *buffer,
			       u32 buffer_len)
{
	if (!(secattr->flags & NETLBL_SECATTR_SECID))
		return -EPERM;

	buffer[0] = CIPSO_V4_TAG_LOCAL;
	buffer[1] = CIPSO_V4_TAG_LOC_BLEN;
	*(u32 *)&buffer[2] = secattr->attr.secid;

	return CIPSO_V4_TAG_LOC_BLEN;
}

/**
 * cipso_v4_parsetag_loc - Parse a CIPSO local tag
 * @doi_def: the DOI definition
 * @tag: the CIPSO tag
 * @secattr: the security attributes
 *
 * Description:
 * Parse a CIPSO local tag and return the security attributes in @secattr.
 * Return zero on success, negatives values on failure.
 *
 */
static int cipso_v4_parsetag_loc(const struct cipso_v4_doi *doi_def,
				 const unsigned char *tag,
				 struct netlbl_lsm_secattr *secattr)
{
	secattr->attr.secid = *(u32 *)&tag[2];
	secattr->flags |= NETLBL_SECATTR_SECID;

	return 0;
}

/**
 * cipso_v4_optptr - Find the CIPSO option in the packet
 * @skb: the packet
 *
 * Description:
 * Parse the packet's IP header looking for a CIPSO option.  Returns a pointer
 * to the start of the CIPSO option on success, NULL if one is not found.
 *
 */
unsigned char *cipso_v4_optptr(const struct sk_buff *skb)
{
	const struct iphdr *iph = ip_hdr(skb);
	unsigned char *optptr = (unsigned char *)&(ip_hdr(skb)[1]);
	int optlen;
	int taglen;

	for (optlen = iph->ihl*4 - sizeof(struct iphdr); optlen > 1; ) {
		switch (optptr[0]) {
		case IPOPT_END:
			return NULL;
		case IPOPT_NOOP:
			taglen = 1;
			break;
		default:
			taglen = optptr[1];
		}
		if (!taglen || taglen > optlen)
			return NULL;
		if (optptr[0] == IPOPT_CIPSO)
			return optptr;

		optlen -= taglen;
		optptr += taglen;
	}

	return NULL;
}

/**
 * cipso_v4_validate - Validate a CIPSO option
 * @skb: the packet
 * @option: the start of the option, on error it is set to point to the error
 *
 * Description:
 * This routine is called to validate a CIPSO option, it checks all of the
 * fields to ensure that they are at least valid, see the draft snippet below
 * for details.  If the option is valid then a zero value is returned and
 * the value of @option is unchanged.  If the option is invalid then a
 * non-zero value is returned and @option is adjusted to point to the
 * offending portion of the option.  From the IETF draft ...
 *
 *  "If any field within the CIPSO options, such as the DOI identifier, is not
 *   recognized the IP datagram is discarded and an ICMP 'parameter problem'
 *   (type 12) is generated and returned.  The ICMP code field is set to 'bad
 *   parameter' (code 0) and the pointer is set to the start of the CIPSO field
 *   that is unrecognized."
 *
 */
int cipso_v4_validate(const struct sk_buff *skb, unsigned char **option)
{
	unsigned char *opt = *option;
	unsigned char *tag;
	unsigned char opt_iter;
	unsigned char err_offset = 0;
	u8 opt_len;
	u8 tag_len;
	struct cipso_v4_doi *doi_def = NULL;
	u32 tag_iter;

	/* caller already checks for length values that are too large */
	opt_len = opt[1];
	if (opt_len < 8) {
		err_offset = 1;
		goto validate_return;
	}

	rcu_read_lock();
	doi_def = cipso_v4_doi_search(get_unaligned_be32(&opt[2]));
	if (!doi_def) {
		err_offset = 2;
		goto validate_return_locked;
	}

	opt_iter = CIPSO_V4_HDR_LEN;
	tag = opt + opt_iter;
	while (opt_iter < opt_len) {
		for (tag_iter = 0; doi_def->tags[tag_iter] != tag[0];)
			if (doi_def->tags[tag_iter] == CIPSO_V4_TAG_INVALID ||
			    ++tag_iter == CIPSO_V4_TAG_MAXCNT) {
				err_offset = opt_iter;
				goto validate_return_locked;
			}

		if (opt_iter + 1 == opt_len) {
			err_offset = opt_iter;
			goto validate_return_locked;
		}
		tag_len = tag[1];
		if (tag_len > (opt_len - opt_iter)) {
			err_offset = opt_iter + 1;
			goto validate_return_locked;
		}

		switch (tag[0]) {
		case CIPSO_V4_TAG_RBITMAP:
			if (tag_len < CIPSO_V4_TAG_RBM_BLEN) {
				err_offset = opt_iter + 1;
				goto validate_return_locked;
			}

			/* We are already going to do all the verification
			 * necessary at the socket layer so from our point of
			 * view it is safe to turn these checks off (and less
			 * work), however, the CIPSO draft says we should do
			 * all the CIPSO validations here but it doesn't
			 * really specify _exactly_ what we need to validate
			 * ... so, just make it a sysctl tunable. */
			if (cipso_v4_rbm_strictvalid) {
				if (cipso_v4_map_lvl_valid(doi_def,
							   tag[3]) < 0) {
					err_offset = opt_iter + 3;
					goto validate_return_locked;
				}
				if (tag_len > CIPSO_V4_TAG_RBM_BLEN &&
				    cipso_v4_map_cat_rbm_valid(doi_def,
							    &tag[4],
							    tag_len - 4) < 0) {
					err_offset = opt_iter + 4;
					goto validate_return_locked;
				}
			}
			break;
		case CIPSO_V4_TAG_ENUM:
			if (tag_len < CIPSO_V4_TAG_ENUM_BLEN) {
				err_offset = opt_iter + 1;
				goto validate_return_locked;
			}

			if (cipso_v4_map_lvl_valid(doi_def,
						   tag[3]) < 0) {
				err_offset = opt_iter + 3;
				goto validate_return_locked;
			}
			if (tag_len > CIPSO_V4_TAG_ENUM_BLEN &&
			    cipso_v4_map_cat_enum_valid(doi_def,
							&tag[4],
							tag_len - 4) < 0) {
				err_offset = opt_iter + 4;
				goto validate_return_locked;
			}
			break;
		case CIPSO_V4_TAG_RANGE:
			if (tag_len < CIPSO_V4_TAG_RNG_BLEN) {
				err_offset = opt_iter + 1;
				goto validate_return_locked;
			}

			if (cipso_v4_map_lvl_valid(doi_def,
						   tag[3]) < 0) {
				err_offset = opt_iter + 3;
				goto validate_return_locked;
			}
			if (tag_len > CIPSO_V4_TAG_RNG_BLEN &&
			    cipso_v4_map_cat_rng_valid(doi_def,
						       &tag[4],
						       tag_len - 4) < 0) {
				err_offset = opt_iter + 4;
				goto validate_return_locked;
			}
			break;
		case CIPSO_V4_TAG_LOCAL:
			/* This is a non-standard tag that we only allow for
			 * local connections, so if the incoming interface is
			 * not the loopback device drop the packet. Further,
			 * there is no legitimate reason for setting this from
			 * userspace so reject it if skb is NULL. */
			if (!skb || !(skb->dev->flags & IFF_LOOPBACK)) {
				err_offset = opt_iter;
				goto validate_return_locked;
			}
			if (tag_len != CIPSO_V4_TAG_LOC_BLEN) {
				err_offset = opt_iter + 1;
				goto validate_return_locked;
			}
			break;
		default:
			err_offset = opt_iter;
			goto validate_return_locked;
		}

		tag += tag_len;
		opt_iter += tag_len;
	}

validate_return_locked:
	rcu_read_unlock();
validate_return:
	*option = opt + err_offset;
	return err_offset;
}

/**
 * cipso_v4_error - Send the correct response for a bad packet
 * @skb: the packet
 * @error: the error code
 * @gateway: CIPSO gateway flag
 *
 * Description:
 * Based on the error code given in @error, send an ICMP error message back to
 * the originating host.  From the IETF draft ...
 *
 *  "If the contents of the CIPSO [option] are valid but the security label is
 *   outside of the configured host or port label range, the datagram is
 *   discarded and an ICMP 'destination unreachable' (type 3) is generated and
 *   returned.  The code field of the ICMP is set to 'communication with
 *   destination network administratively prohibited' (code 9) or to
 *   'communication with destination host administratively prohibited'
 *   (code 10).  The value of the code is dependent on whether the originator
 *   of the ICMP message is acting as a CIPSO host or a CIPSO gateway.  The
 *   recipient of the ICMP message MUST be able to handle either value.  The
 *   same procedure is performed if a CIPSO [option] can not be added to an
 *   IP packet because it is too large to fit in the IP options area."
 *
 *  "If the error is triggered by receipt of an ICMP message, the message is
 *   discarded and no response is permitted (consistent with general ICMP
 *   processing rules)."
 *
 */
void cipso_v4_error(struct sk_buff *skb, int error, u32 gateway)
{
	unsigned char optbuf[sizeof(struct ip_options) + 40];
	struct ip_options *opt = (struct ip_options *)optbuf;
	int res;

	if (ip_hdr(skb)->protocol == IPPROTO_ICMP || error != -EACCES)
		return;

	/*
	 * We might be called above the IP layer,
	 * so we can not use icmp_send and IPCB here.
	 */

	memset(opt, 0, sizeof(struct ip_options));
	opt->optlen = ip_hdr(skb)->ihl*4 - sizeof(struct iphdr);
	rcu_read_lock();
	res = __ip_options_compile(dev_net(skb->dev), opt, skb, NULL);
	rcu_read_unlock();

	if (res)
		return;

	if (gateway)
		__icmp_send(skb, ICMP_DEST_UNREACH, ICMP_NET_ANO, 0, opt);
	else
		__icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_ANO, 0, opt);
}

/**
 * cipso_v4_genopt - Generate a CIPSO option
 * @buf: the option buffer
 * @buf_len: the size of opt_buf
 * @doi_def: the CIPSO DOI to use
 * @secattr: the security attributes
 *
 * Description:
 * Generate a CIPSO option using the DOI definition and security attributes
 * passed to the function.  Returns the length of the option on success and
 * negative values on failure.
 *
 */
static int cipso_v4_genopt(unsigned char *buf, u32 buf_len,
			   const struct cipso_v4_doi *doi_def,
			   const struct netlbl_lsm_secattr *secattr)
{
	int ret_val;
	u32 iter;

	if (buf_len <= CIPSO_V4_HDR_LEN)
		return -ENOSPC;

	/* XXX - This code assumes only one tag per CIPSO option which isn't
	 * really a good assumption to make but since we only support the MAC
	 * tags right now it is a safe assumption. */
	iter = 0;
	do {
		memset(buf, 0, buf_len);
		switch (doi_def->tags[iter]) {
		case CIPSO_V4_TAG_RBITMAP:
			ret_val = cipso_v4_gentag_rbm(doi_def,
						   secattr,
						   &buf[CIPSO_V4_HDR_LEN],
						   buf_len - CIPSO_V4_HDR_LEN);
			break;
		case CIPSO_V4_TAG_ENUM:
			ret_val = cipso_v4_gentag_enum(doi_def,
						   secattr,
						   &buf[CIPSO_V4_HDR_LEN],
						   buf_len - CIPSO_V4_HDR_LEN);
			break;
		case CIPSO_V4_TAG_RANGE:
			ret_val = cipso_v4_gentag_rng(doi_def,
						   secattr,
						   &buf[CIPSO_V4_HDR_LEN],
						   buf_len - CIPSO_V4_HDR_LEN);
			break;
		case CIPSO_V4_TAG_LOCAL:
			ret_val = cipso_v4_gentag_loc(doi_def,
						   secattr,
						   &buf[CIPSO_V4_HDR_LEN],
						   buf_len - CIPSO_V4_HDR_LEN);
			break;
		default:
			return -EPERM;
		}

		iter++;
	} while (ret_val < 0 &&
		 iter < CIPSO_V4_TAG_MAXCNT &&
		 doi_def->tags[iter] != CIPSO_V4_TAG_INVALID);
	if (ret_val < 0)
		return ret_val;
	cipso_v4_gentag_hdr(doi_def, buf, ret_val);
	return CIPSO_V4_HDR_LEN + ret_val;
}

/**
 * cipso_v4_sock_setattr - Add a CIPSO option to a socket
 * @sk: the socket
 * @doi_def: the CIPSO DOI to use
 * @secattr: the specific security attributes of the socket
 *
 * Description:
 * Set the CIPSO option on the given socket using the DOI definition and
 * security attributes passed to the function.  This function requires
 * exclusive access to @sk, which means it either needs to be in the
 * process of being created or locked.  Returns zero on success and negative
 * values on failure.
 *
 */
int cipso_v4_sock_setattr(struct sock *sk,
			  const struct cipso_v4_doi *doi_def,
			  const struct netlbl_lsm_secattr *secattr)
{
	int ret_val = -EPERM;
	unsigned char *buf = NULL;
	u32 buf_len;
	u32 opt_len;
	struct ip_options_rcu *old, *opt = NULL;
	struct inet_sock *sk_inet;
	struct inet_connection_sock *sk_conn;

	/* In the case of sock_create_lite(), the sock->sk field is not
	 * defined yet but it is not a problem as the only users of these
	 * "lite" PF_INET sockets are functions which do an accept() call
	 * afterwards so we will label the socket as part of the accept(). */
	if (!sk)
		return 0;

	/* We allocate the maximum CIPSO option size here so we are probably
	 * being a little wasteful, but it makes our life _much_ easier later
	 * on and after all we are only talking about 40 bytes. */
	buf_len = CIPSO_V4_OPT_LEN_MAX;
	buf = kmalloc(buf_len, GFP_ATOMIC);
	if (!buf) {
		ret_val = -ENOMEM;
		goto socket_setattr_failure;
	}

	ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr);
	if (ret_val < 0)
		goto socket_setattr_failure;
	buf_len = ret_val;

	/* We can't use ip_options_get() directly because it makes a call to
	 * ip_options_get_alloc() which allocates memory with GFP_KERNEL and
	 * we won't always have CAP_NET_RAW even though we _always_ want to
	 * set the IPOPT_CIPSO option. */
	opt_len = (buf_len + 3) & ~3;
	opt = kzalloc(sizeof(*opt) + opt_len, GFP_ATOMIC);
	if (!opt) {
		ret_val = -ENOMEM;
		goto socket_setattr_failure;
	}
	memcpy(opt->opt.__data, buf, buf_len);
	opt->opt.optlen = opt_len;
	opt->opt.cipso = sizeof(struct iphdr);
	kfree(buf);
	buf = NULL;

	sk_inet = inet_sk(sk);

	old = rcu_dereference_protected(sk_inet->inet_opt,
					lockdep_sock_is_held(sk));
	if (sk_inet->is_icsk) {
		sk_conn = inet_csk(sk);
		if (old)
			sk_conn->icsk_ext_hdr_len -= old->opt.optlen;
		sk_conn->icsk_ext_hdr_len += opt->opt.optlen;
		sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie);
	}
	rcu_assign_pointer(sk_inet->inet_opt, opt);
	if (old)
		kfree_rcu(old, rcu);

	return 0;

socket_setattr_failure:
	kfree(buf);
	kfree(opt);
	return ret_val;
}

/**
 * cipso_v4_req_setattr - Add a CIPSO option to a connection request socket
 * @req: the connection request socket
 * @doi_def: the CIPSO DOI to use
 * @secattr: the specific security attributes of the socket
 *
 * Description:
 * Set the CIPSO option on the given socket using the DOI definition and
 * security attributes passed to the function.  Returns zero on success and
 * negative values on failure.
 *
 */
int cipso_v4_req_setattr(struct request_sock *req,
			 const struct cipso_v4_doi *doi_def,
			 const struct netlbl_lsm_secattr *secattr)
{
	int ret_val = -EPERM;
	unsigned char *buf = NULL;
	u32 buf_len;
	u32 opt_len;
	struct ip_options_rcu *opt = NULL;
	struct inet_request_sock *req_inet;

	/* We allocate the maximum CIPSO option size here so we are probably
	 * being a little wasteful, but it makes our life _much_ easier later
	 * on and after all we are only talking about 40 bytes. */
	buf_len = CIPSO_V4_OPT_LEN_MAX;
	buf = kmalloc(buf_len, GFP_ATOMIC);
	if (!buf) {
		ret_val = -ENOMEM;
		goto req_setattr_failure;
	}

	ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr);
	if (ret_val < 0)
		goto req_setattr_failure;
	buf_len = ret_val;

	/* We can't use ip_options_get() directly because it makes a call to
	 * ip_options_get_alloc() which allocates memory with GFP_KERNEL and
	 * we won't always have CAP_NET_RAW even though we _always_ want to
	 * set the IPOPT_CIPSO option. */
	opt_len = (buf_len + 3) & ~3;
	opt = kzalloc(sizeof(*opt) + opt_len, GFP_ATOMIC);
	if (!opt) {
		ret_val = -ENOMEM;
		goto req_setattr_failure;
	}
	memcpy(opt->opt.__data, buf, buf_len);
	opt->opt.optlen = opt_len;
	opt->opt.cipso = sizeof(struct iphdr);
	kfree(buf);
	buf = NULL;

	req_inet = inet_rsk(req);
	opt = xchg((__force struct ip_options_rcu **)&req_inet->ireq_opt, opt);
	if (opt)
		kfree_rcu(opt, rcu);

	return 0;

req_setattr_failure:
	kfree(buf);
	kfree(opt);
	return ret_val;
}

/**
 * cipso_v4_delopt - Delete the CIPSO option from a set of IP options
 * @opt_ptr: IP option pointer
 *
 * Description:
 * Deletes the CIPSO IP option from a set of IP options and makes the necessary
 * adjustments to the IP option structure.  Returns zero on success, negative
 * values on failure.
 *
 */
static int cipso_v4_delopt(struct ip_options_rcu __rcu **opt_ptr)
{
	struct ip_options_rcu *opt = rcu_dereference_protected(*opt_ptr, 1);
	int hdr_delta = 0;

	if (!opt || opt->opt.cipso == 0)
		return 0;
	if (opt->opt.srr || opt->opt.rr || opt->opt.ts || opt->opt.router_alert) {
		u8 cipso_len;
		u8 cipso_off;
		unsigned char *cipso_ptr;
		int iter;
		int optlen_new;

		cipso_off = opt->opt.cipso - sizeof(struct iphdr);
		cipso_ptr = &opt->opt.__data[cipso_off];
		cipso_len = cipso_ptr[1];

		if (opt->opt.srr > opt->opt.cipso)
			opt->opt.srr -= cipso_len;
		if (opt->opt.rr > opt->opt.cipso)
			opt->opt.rr -= cipso_len;
		if (opt->opt.ts > opt->opt.cipso)
			opt->opt.ts -= cipso_len;
		if (opt->opt.router_alert > opt->opt.cipso)
			opt->opt.router_alert -= cipso_len;
		opt->opt.cipso = 0;

		memmove(cipso_ptr, cipso_ptr + cipso_len,
			opt->opt.optlen - cipso_off - cipso_len);

		/* determining the new total option length is tricky because of
		 * the padding necessary, the only thing i can think to do at
		 * this point is walk the options one-by-one, skipping the
		 * padding at the end to determine the actual option size and
		 * from there we can determine the new total option length */
		iter = 0;
		optlen_new = 0;
		while (iter < opt->opt.optlen)
			if (opt->opt.__data[iter] != IPOPT_NOP) {
				iter += opt->opt.__data[iter + 1];
				optlen_new = iter;
			} else
				iter++;
		hdr_delta = opt->opt.optlen;
		opt->opt.optlen = (optlen_new + 3) & ~3;
		hdr_delta -= opt->opt.optlen;
	} else {
		/* only the cipso option was present on the socket so we can
		 * remove the entire option struct */
		*opt_ptr = NULL;
		hdr_delta = opt->opt.optlen;
		kfree_rcu(opt, rcu);
	}

	return hdr_delta;
}

/**
 * cipso_v4_sock_delattr - Delete the CIPSO option from a socket
 * @sk: the socket
 *
 * Description:
 * Removes the CIPSO option from a socket, if present.
 *
 */
void cipso_v4_sock_delattr(struct sock *sk)
{
	struct inet_sock *sk_inet;
	int hdr_delta;

	sk_inet = inet_sk(sk);

	hdr_delta = cipso_v4_delopt(&sk_inet->inet_opt);
	if (sk_inet->is_icsk && hdr_delta > 0) {
		struct inet_connection_sock *sk_conn = inet_csk(sk);
		sk_conn->icsk_ext_hdr_len -= hdr_delta;
		sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie);
	}
}

/**
 * cipso_v4_req_delattr - Delete the CIPSO option from a request socket
 * @req: the request socket
 *
 * Description:
 * Removes the CIPSO option from a request socket, if present.
 *
 */
void cipso_v4_req_delattr(struct request_sock *req)
{
	cipso_v4_delopt(&inet_rsk(req)->ireq_opt);
}

/**
 * cipso_v4_getattr - Helper function for the cipso_v4_*_getattr functions
 * @cipso: the CIPSO v4 option
 * @secattr: the security attributes
 *
 * Description:
 * Inspect @cipso and return the security attributes in @secattr.  Returns zero
 * on success and negative values on failure.
 *
 */
int cipso_v4_getattr(const unsigned char *cipso,
		     struct netlbl_lsm_secattr *secattr)
{
	int ret_val = -ENOMSG;
	u32 doi;
	struct cipso_v4_doi *doi_def;

	if (cipso_v4_cache_check(cipso, cipso[1], secattr) == 0)
		return 0;

	doi = get_unaligned_be32(&cipso[2]);
	rcu_read_lock();
	doi_def = cipso_v4_doi_search(doi);
	if (!doi_def)
		goto getattr_return;
	/* XXX - This code assumes only one tag per CIPSO option which isn't
	 * really a good assumption to make but since we only support the MAC
	 * tags right now it is a safe assumption. */
	switch (cipso[6]) {
	case CIPSO_V4_TAG_RBITMAP:
		ret_val = cipso_v4_parsetag_rbm(doi_def, &cipso[6], secattr);
		break;
	case CIPSO_V4_TAG_ENUM:
		ret_val = cipso_v4_parsetag_enum(doi_def, &cipso[6], secattr);
		break;
	case CIPSO_V4_TAG_RANGE:
		ret_val = cipso_v4_parsetag_rng(doi_def, &cipso[6], secattr);
		break;
	case CIPSO_V4_TAG_LOCAL:
		ret_val = cipso_v4_parsetag_loc(doi_def, &cipso[6], secattr);
		break;
	}
	if (ret_val == 0)
		secattr->type = NETLBL_NLTYPE_CIPSOV4;

getattr_return:
	rcu_read_unlock();
	return ret_val;
}

/**
 * cipso_v4_sock_getattr - Get the security attributes from a sock
 * @sk: the sock
 * @secattr: the security attributes
 *
 * Description:
 * Query @sk to see if there is a CIPSO option attached to the sock and if
 * there is return the CIPSO security attributes in @secattr.  This function
 * requires that @sk be locked, or privately held, but it does not do any
 * locking itself.  Returns zero on success and negative values on failure.
 *
 */
int cipso_v4_sock_getattr(struct sock *sk, struct netlbl_lsm_secattr *secattr)
{
	struct ip_options_rcu *opt;
	int res = -ENOMSG;

	rcu_read_lock();
	opt = rcu_dereference(inet_sk(sk)->inet_opt);
	if (opt && opt->opt.cipso)
		res = cipso_v4_getattr(opt->opt.__data +
						opt->opt.cipso -
						sizeof(struct iphdr),
				       secattr);
	rcu_read_unlock();
	return res;
}

/**
 * cipso_v4_skbuff_setattr - Set the CIPSO option on a packet
 * @skb: the packet
 * @doi_def: the DOI structure
 * @secattr: the security attributes
 *
 * Description:
 * Set the CIPSO option on the given packet based on the security attributes.
 * Returns a pointer to the IP header on success and NULL on failure.
 *
 */
int cipso_v4_skbuff_setattr(struct sk_buff *skb,
			    const struct cipso_v4_doi *doi_def,
			    const struct netlbl_lsm_secattr *secattr)
{
	int ret_val;
	struct iphdr *iph;
	struct ip_options *opt = &IPCB(skb)->opt;
	unsigned char buf[CIPSO_V4_OPT_LEN_MAX];
	u32 buf_len = CIPSO_V4_OPT_LEN_MAX;
	u32 opt_len;
	int len_delta;

	ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr);
	if (ret_val < 0)
		return ret_val;
	buf_len = ret_val;
	opt_len = (buf_len + 3) & ~3;

	/* we overwrite any existing options to ensure that we have enough
	 * room for the CIPSO option, the reason is that we _need_ to guarantee
	 * that the security label is applied to the packet - we do the same
	 * thing when using the socket options and it hasn't caused a problem,
	 * if we need to we can always revisit this choice later */

	len_delta = opt_len - opt->optlen;
	/* if we don't ensure enough headroom we could panic on the skb_push()
	 * call below so make sure we have enough, we are also "mangling" the
	 * packet so we should probably do a copy-on-write call anyway */
	ret_val = skb_cow(skb, skb_headroom(skb) + len_delta);
	if (ret_val < 0)
		return ret_val;

	if (len_delta > 0) {
		/* we assume that the header + opt->optlen have already been
		 * "pushed" in ip_options_build() or similar */
		iph = ip_hdr(skb);
		skb_push(skb, len_delta);
		memmove((char *)iph - len_delta, iph, iph->ihl << 2);
		skb_reset_network_header(skb);
		iph = ip_hdr(skb);
	} else if (len_delta < 0) {
		iph = ip_hdr(skb);
		memset(iph + 1, IPOPT_NOP, opt->optlen);
	} else
		iph = ip_hdr(skb);

	if (opt->optlen > 0)
		memset(opt, 0, sizeof(*opt));
	opt->optlen = opt_len;
	opt->cipso = sizeof(struct iphdr);
	opt->is_changed = 1;

	/* we have to do the following because we are being called from a
	 * netfilter hook which means the packet already has had the header
	 * fields populated and the checksum calculated - yes this means we
	 * are doing more work than needed but we do it to keep the core
	 * stack clean and tidy */
	memcpy(iph + 1, buf, buf_len);
	if (opt_len > buf_len)
		memset((char *)(iph + 1) + buf_len, 0, opt_len - buf_len);
	if (len_delta != 0) {
		iph->ihl = 5 + (opt_len >> 2);
		iph->tot_len = htons(skb->len);
	}
	ip_send_check(iph);

	return 0;
}

/**
 * cipso_v4_skbuff_delattr - Delete any CIPSO options from a packet
 * @skb: the packet
 *
 * Description:
 * Removes any and all CIPSO options from the given packet.  Returns zero on
 * success, negative values on failure.
 *
 */
int cipso_v4_skbuff_delattr(struct sk_buff *skb)
{
	int ret_val;
	struct iphdr *iph;
	struct ip_options *opt = &IPCB(skb)->opt;
	unsigned char *cipso_ptr;

	if (opt->cipso == 0)
		return 0;

	/* since we are changing the packet we should make a copy */
	ret_val = skb_cow(skb, skb_headroom(skb));
	if (ret_val < 0)
		return ret_val;

	/* the easiest thing to do is just replace the cipso option with noop
	 * options since we don't change the size of the packet, although we
	 * still need to recalculate the checksum */

	iph = ip_hdr(skb);
	cipso_ptr = (unsigned char *)iph + opt->cipso;
	memset(cipso_ptr, IPOPT_NOOP, cipso_ptr[1]);
	opt->cipso = 0;
	opt->is_changed = 1;

	ip_send_check(iph);

	return 0;
}

/*
 * Setup Functions
 */

/**
 * cipso_v4_init - Initialize the CIPSO module
 *
 * Description:
 * Initialize the CIPSO module and prepare it for use.  Returns zero on success
 * and negative values on failure.
 *
 */
static int __init cipso_v4_init(void)
{
	int ret_val;

	ret_val = cipso_v4_cache_init();
	if (ret_val != 0)
		panic("Failed to initialize the CIPSO/IPv4 cache (%d)\n",
		      ret_val);

	return 0;
}

subsys_initcall(cipso_v4_init);