aboutsummaryrefslogtreecommitdiffstats
path: root/net/ipv4/cipso_ipv4.c
blob: 70858dccaca200ac10a2614a49ccd0d3e3842eb6 (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
/*
 * 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, copies of both documents can be found in the Documentation
 * directory.  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.
 *
 * Author: Paul Moore <paul.moore@hp.com>
 *
 */

/*
 * (c) Copyright Hewlett-Packard Development Company, L.P., 2006
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 */

#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 <net/ip.h>
#include <net/icmp.h>
#include <net/tcp.h>
#include <net/netlabel.h>
#include <net/cipso_ipv4.h>
#include <asm/atomic.h>
#include <asm/bug.h>

struct cipso_v4_domhsh_entry {
	char *domain;
	u32 valid;
	struct list_head list;
	struct rcu_head rcu;
};

/* List of available DOI definitions */
/* XXX - Updates should be minimal so having a single lock for the
 * cipso_v4_doi_list and the cipso_v4_doi_list->dom_list should be
 * okay. */
/* 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 struct list_head cipso_v4_doi_list = LIST_HEAD_INIT(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 = NULL;

/* Restricted bitmap (tag #1) flags */
int cipso_v4_rbm_optfmt = 0;
int cipso_v4_rbm_strictvalid = 1;

/*
 * Helper Functions
 */

/**
 * cipso_v4_bitmap_walk - Walk a bitmap looking for a bit
 * @bitmap: the bitmap
 * @bitmap_len: length in bits
 * @offset: starting offset
 * @state: if non-zero, look for a set (1) bit else look for a cleared (0) bit
 *
 * Description:
 * Starting at @offset, walk the bitmap from left to right until either the
 * desired bit is found or we reach the end.  Return the bit offset, -1 if
 * not found, or -2 if error.
 */
static int cipso_v4_bitmap_walk(const unsigned char *bitmap,
				u32 bitmap_len,
				u32 offset,
				u8 state)
{
	u32 bit_spot;
	u32 byte_offset;
	unsigned char bitmask;
	unsigned char byte;

	/* gcc always rounds to zero when doing integer division */
	byte_offset = offset / 8;
	byte = bitmap[byte_offset];
	bit_spot = offset;
	bitmask = 0x80 >> (offset % 8);

	while (bit_spot < bitmap_len) {
		if ((state && (byte & bitmask) == bitmask) ||
		    (state == 0 && (byte & bitmask) == 0))
			return bit_spot;

		bit_spot++;
		bitmask >>= 1;
		if (bitmask == 0) {
			byte = bitmap[++byte_offset];
			bitmask = 0x80;
		}
	}

	return -1;
}

/**
 * cipso_v4_bitmap_setbit - Sets a single bit in a bitmap
 * @bitmap: the bitmap
 * @bit: the bit
 * @state: if non-zero, set the bit (1) else clear the bit (0)
 *
 * Description:
 * Set a single bit in the bitmask.  Returns zero on success, negative values
 * on error.
 */
static void cipso_v4_bitmap_setbit(unsigned char *bitmap,
				   u32 bit,
				   u8 state)
{
	u32 byte_spot;
	u8 bitmask;

	/* gcc always rounds to zero when doing integer division */
	byte_spot = bit / 8;
	bitmask = 0x80 >> (bit % 8);
	if (state)
		bitmap[byte_spot] |= bitmask;
	else
		bitmap[byte_spot] &= ~bitmask;
}

/**
 * cipso_v4_doi_domhsh_free - Frees a domain list entry
 * @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 a domain list entry can be released
 * safely.
 *
 */
static void cipso_v4_doi_domhsh_free(struct rcu_head *entry)
{
	struct cipso_v4_domhsh_entry *ptr;

	ptr = container_of(entry, struct cipso_v4_domhsh_entry, rcu);
	kfree(ptr->domain);
	kfree(ptr);
}

/**
 * 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 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 == NULL)
		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.  Returns zero on
 * success and negative values on failure.
 *
 */
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);
	}

	return;
}

/**
 * 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_BUCKETBITS - 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;
			atomic_inc(&entry->lsm_data->refcount);
			secattr->cache = entry->lsm_data;
			secattr->flags |= NETLBL_SECATTR_CACHE;
			if (prev_entry == NULL) {
				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
 * @skb: the packet
 * @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 struct sk_buff *skb,
		       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;
	unsigned char *cipso_ptr;
	u32 cipso_ptr_len;

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

	cipso_ptr = CIPSO_V4_OPTPTR(skb);
	cipso_ptr_len = cipso_ptr[1];

	entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
	if (entry == NULL)
		return -ENOMEM;
	entry->key = kmemdup(cipso_ptr, cipso_ptr_len, GFP_ATOMIC);
	if (entry->key == NULL) {
		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);
	atomic_inc(&secattr->cache->refcount);
	entry->lsm_data = secattr->cache;

	bkt = entry->hash & (CIPSO_V4_CACHE_BUCKETBITS - 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 responsibile 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 && iter->valid)
			return iter;
	return NULL;
}

/**
 * cipso_v4_doi_add - Add a new DOI to the CIPSO protocol engine
 * @doi_def: the DOI structure
 *
 * 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)
{
	u32 iter;

	if (doi_def == NULL || doi_def->doi == CIPSO_V4_DOI_UNKNOWN)
		return -EINVAL;
	for (iter = 0; iter < CIPSO_V4_TAG_MAXCNT; iter++) {
		switch (doi_def->tags[iter]) {
		case CIPSO_V4_TAG_RBITMAP:
			break;
		case CIPSO_V4_TAG_INVALID:
			if (iter == 0)
				return -EINVAL;
			break;
		case CIPSO_V4_TAG_ENUM:
			if (doi_def->type != CIPSO_V4_MAP_PASS)
				return -EINVAL;
			break;
		default:
			return -EINVAL;
		}
	}

	doi_def->valid = 1;
	INIT_RCU_HEAD(&doi_def->rcu);
	INIT_LIST_HEAD(&doi_def->dom_list);

	rcu_read_lock();
	if (cipso_v4_doi_search(doi_def->doi) != NULL)
		goto doi_add_failure_rlock;
	spin_lock(&cipso_v4_doi_list_lock);
	if (cipso_v4_doi_search(doi_def->doi) != NULL)
		goto doi_add_failure_slock;
	list_add_tail_rcu(&doi_def->list, &cipso_v4_doi_list);
	spin_unlock(&cipso_v4_doi_list_lock);
	rcu_read_unlock();

	return 0;

doi_add_failure_slock:
	spin_unlock(&cipso_v4_doi_list_lock);
doi_add_failure_rlock:
	rcu_read_unlock();
	return -EEXIST;
}

/**
 * cipso_v4_doi_remove - Remove an existing DOI from the CIPSO protocol engine
 * @doi: the DOI value
 * @audit_secid: the LSM secid to use in the audit message
 * @callback: the DOI cleanup/free callback
 *
 * Description:
 * Removes a DOI definition from the CIPSO engine, @callback is called to
 * free any memory.  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,
			void (*callback) (struct rcu_head * head))
{
	struct cipso_v4_doi *doi_def;
	struct cipso_v4_domhsh_entry *dom_iter;

	rcu_read_lock();
	if (cipso_v4_doi_search(doi) != NULL) {
		spin_lock(&cipso_v4_doi_list_lock);
		doi_def = cipso_v4_doi_search(doi);
		if (doi_def == NULL) {
			spin_unlock(&cipso_v4_doi_list_lock);
			rcu_read_unlock();
			return -ENOENT;
		}
		doi_def->valid = 0;
		list_del_rcu(&doi_def->list);
		spin_unlock(&cipso_v4_doi_list_lock);
		list_for_each_entry_rcu(dom_iter, &doi_def->dom_list, list)
			if (dom_iter->valid)
				netlbl_domhsh_remove(dom_iter->domain,
						     audit_info);
		cipso_v4_cache_invalidate();
		rcu_read_unlock();

		call_rcu(&doi_def->rcu, callback);
		return 0;
	}
	rcu_read_unlock();

	return -ENOENT;
}

/**
 * cipso_v4_doi_getdef - Returns a pointer 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.
 *
 */
struct cipso_v4_doi *cipso_v4_doi_getdef(u32 doi)
{
	return cipso_v4_doi_search(doi);
}

/**
 * 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 (iter_doi->valid) {
			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;
}

/**
 * cipso_v4_doi_domhsh_add - Adds a domain entry to a DOI definition
 * @doi_def: the DOI definition
 * @domain: the domain to add
 *
 * Description:
 * Adds the @domain to the the DOI specified by @doi_def, this function
 * should only be called by external functions (i.e. NetLabel).  This function
 * does allocate memory.  Returns zero on success, negative values on failure.
 *
 */
int cipso_v4_doi_domhsh_add(struct cipso_v4_doi *doi_def, const char *domain)
{
	struct cipso_v4_domhsh_entry *iter;
	struct cipso_v4_domhsh_entry *new_dom;

	new_dom = kzalloc(sizeof(*new_dom), GFP_KERNEL);
	if (new_dom == NULL)
		return -ENOMEM;
	if (domain) {
		new_dom->domain = kstrdup(domain, GFP_KERNEL);
		if (new_dom->domain == NULL) {
			kfree(new_dom);
			return -ENOMEM;
		}
	}
	new_dom->valid = 1;
	INIT_RCU_HEAD(&new_dom->rcu);

	rcu_read_lock();
	spin_lock(&cipso_v4_doi_list_lock);
	list_for_each_entry_rcu(iter, &doi_def->dom_list, list)
		if (iter->valid &&
		    ((domain != NULL && iter->domain != NULL &&
		      strcmp(iter->domain, domain) == 0) ||
		     (domain == NULL && iter->domain == NULL))) {
			spin_unlock(&cipso_v4_doi_list_lock);
			rcu_read_unlock();
			kfree(new_dom->domain);
			kfree(new_dom);
			return -EEXIST;
		}
	list_add_tail_rcu(&new_dom->list, &doi_def->dom_list);
	spin_unlock(&cipso_v4_doi_list_lock);
	rcu_read_unlock();

	return 0;
}

/**
 * cipso_v4_doi_domhsh_remove - Removes a domain entry from a DOI definition
 * @doi_def: the DOI definition
 * @domain: the domain to remove
 *
 * Description:
 * Removes the @domain from the DOI specified by @doi_def, this function
 * should only be called by external functions (i.e. NetLabel).   Returns zero
 * on success and negative values on error.
 *
 */
int cipso_v4_doi_domhsh_remove(struct cipso_v4_doi *doi_def,
			       const char *domain)
{
	struct cipso_v4_domhsh_entry *iter;

	rcu_read_lock();
	spin_lock(&cipso_v4_doi_list_lock);
	list_for_each_entry_rcu(iter, &doi_def->dom_list, list)
		if (iter->valid &&
		    ((domain != NULL && iter->domain != NULL &&
		      strcmp(iter->domain, domain) == 0) ||
		     (domain == NULL && iter->domain == NULL))) {
			iter->valid = 0;
			list_del_rcu(&iter->list);
			spin_unlock(&cipso_v4_doi_list_lock);
			rcu_read_unlock();
			call_rcu(&iter->rcu, cipso_v4_doi_domhsh_free);

			return 0;
		}
	spin_unlock(&cipso_v4_doi_list_lock);
	rcu_read_unlock();

	return -ENOENT;
}

/*
 * 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_STD:
		if (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_STD:
		if (host_lvl < doi_def->map.std->lvl.local_size) {
			*net_lvl = doi_def->map.std->lvl.local[host_lvl];
			return 0;
		}
		break;
	}

	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_STD:
		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;
		}
		break;
	}

	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_STD:
		cipso_cat_size = doi_def->map.std->cat.cipso_size;
		cipso_array = doi_def->map.std->cat.cipso;
		for (;;) {
			cat = cipso_v4_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_STD) {
		host_cat_size = doi_def->map.std->cat.local_size;
		host_cat_array = doi_def->map.std->cat.local;
	}

	for (;;) {
		host_spot = netlbl_secattr_catmap_walk(secattr->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_STD:
			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;
		cipso_v4_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_STD) {
		net_cat_size = doi_def->map.std->cat.cipso_size;
		net_cat_array = doi_def->map.std->cat.cipso;
	}

	for (;;) {
		net_spot = cipso_v4_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_STD:
			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_secattr_catmap_setbit(secattr->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 = ntohs(*((__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_secattr_catmap_walk(secattr->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_secattr_catmap_setbit(secattr->mls_cat,
					    ntohs(*((__be16 *)&net_cat[iter])),
					    GFP_ATOMIC);
		if (ret_val != 0)
			return ret_val;
	}

	return 0;
}

/*
 * Protocol Handling Functions
 */

#define CIPSO_V4_OPT_LEN_MAX          40
#define CIPSO_V4_HDR_LEN              6

/**
 * 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;
	*(__be32 *)&buf[2] = htonl(doi_def->doi);
}

/**
 * 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->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
		 * possibile 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] = 0x01;
	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->mls_lvl = level;
	secattr->flags |= NETLBL_SECATTR_MLS_LVL;

	if (tag_len > 4) {
		secattr->mls_cat = netlbl_secattr_catmap_alloc(GFP_ATOMIC);
		if (secattr->mls_cat == NULL)
			return -ENOMEM;

		ret_val = cipso_v4_map_cat_rbm_ntoh(doi_def,
						    &tag[4],
						    tag_len - 4,
						    secattr);
		if (ret_val != 0) {
			netlbl_secattr_catmap_free(secattr->mls_cat);
			return ret_val;
		}

		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->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] = 0x02;
	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->mls_lvl = level;
	secattr->flags |= NETLBL_SECATTR_MLS_LVL;

	if (tag_len > 4) {
		secattr->mls_cat = netlbl_secattr_catmap_alloc(GFP_ATOMIC);
		if (secattr->mls_cat == NULL)
			return -ENOMEM;

		ret_val = cipso_v4_map_cat_enum_ntoh(doi_def,
						     &tag[4],
						     tag_len - 4,
						     secattr);
		if (ret_val != 0) {
			netlbl_secattr_catmap_free(secattr->mls_cat);
			return ret_val;
		}

		secattr->flags |= NETLBL_SECATTR_MLS_CAT;
	}

	return 0;
}

/**
 * cipso_v4_validate - Validate a CIPSO option
 * @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(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(ntohl(*((__be32 *)&opt[2])));
	if (doi_def == NULL) {
		err_offset = 2;
		goto validate_return_locked;
	}

	opt_iter = 6;
	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;
			}

		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 < 4) {
				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 > 4 &&
				    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 < 4) {
				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 > 4 &&
			    cipso_v4_map_cat_enum_valid(doi_def,
							&tag[4],
							tag_len - 4) < 0) {
				err_offset = opt_iter + 4;
				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 reponse 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)
{
	if (skb->nh.iph->protocol == IPPROTO_ICMP || error != -EACCES)
		return;

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

/**
 * cipso_v4_socket_setattr - Add a CIPSO option to a socket
 * @sock: 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 @sock->sk, which means it either needs to be in the
 * process of being created or locked via lock_sock(sock->sk).  Returns zero on
 * success and negative values on failure.
 *
 */
int cipso_v4_socket_setattr(const struct socket *sock,
			    const struct cipso_v4_doi *doi_def,
			    const struct netlbl_lsm_secattr *secattr)
{
	int ret_val = -EPERM;
	u32 iter;
	unsigned char *buf;
	u32 buf_len = 0;
	u32 opt_len;
	struct ip_options *opt = NULL;
	struct sock *sk;
	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(). */
	sk = sock->sk;
	if (sk == NULL)
		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 == NULL) {
		ret_val = -ENOMEM;
		goto socket_setattr_failure;
	}

	/* 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;
		default:
			ret_val = -EPERM;
			goto socket_setattr_failure;
		}

		iter++;
	} while (ret_val < 0 &&
		 iter < CIPSO_V4_TAG_MAXCNT &&
		 doi_def->tags[iter] != CIPSO_V4_TAG_INVALID);
	if (ret_val < 0)
		goto socket_setattr_failure;
	cipso_v4_gentag_hdr(doi_def, buf, ret_val);
	buf_len = CIPSO_V4_HDR_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 == NULL) {
		ret_val = -ENOMEM;
		goto socket_setattr_failure;
	}
	memcpy(opt->__data, buf, buf_len);
	opt->optlen = opt_len;
	opt->is_data = 1;
	opt->cipso = sizeof(struct iphdr);
	kfree(buf);
	buf = NULL;

	sk_inet = inet_sk(sk);
	if (sk_inet->is_icsk) {
		sk_conn = inet_csk(sk);
		if (sk_inet->opt)
			sk_conn->icsk_ext_hdr_len -= sk_inet->opt->optlen;
		sk_conn->icsk_ext_hdr_len += opt->optlen;
		sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie);
	}
	opt = xchg(&sk_inet->opt, opt);
	kfree(opt);

	return 0;

socket_setattr_failure:
	kfree(buf);
	kfree(opt);
	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)
{
	int ret_val = -ENOMSG;
	struct inet_sock *sk_inet;
	unsigned char *cipso_ptr;
	u32 doi;
	struct cipso_v4_doi *doi_def;

	sk_inet = inet_sk(sk);
	if (sk_inet->opt == NULL || sk_inet->opt->cipso == 0)
		return -ENOMSG;
	cipso_ptr = sk_inet->opt->__data + sk_inet->opt->cipso -
		sizeof(struct iphdr);
	ret_val = cipso_v4_cache_check(cipso_ptr, cipso_ptr[1], secattr);
	if (ret_val == 0)
		return ret_val;

	doi = ntohl(*(__be32 *)&cipso_ptr[2]);
	rcu_read_lock();
	doi_def = cipso_v4_doi_search(doi);
	if (doi_def == NULL) {
		rcu_read_unlock();
		return -ENOMSG;
	}

	/* 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_ptr[6]) {
	case CIPSO_V4_TAG_RBITMAP:
		ret_val = cipso_v4_parsetag_rbm(doi_def,
						&cipso_ptr[6],
						secattr);
		break;
	case CIPSO_V4_TAG_ENUM:
		ret_val = cipso_v4_parsetag_enum(doi_def,
						 &cipso_ptr[6],
						 secattr);
		break;
	}
	rcu_read_unlock();

	return ret_val;
}

/**
 * cipso_v4_socket_getattr - Get the security attributes from a socket
 * @sock: the socket
 * @secattr: the security attributes
 *
 * Description:
 * Query @sock to see if there is a CIPSO option attached to the socket and if
 * there is return the CIPSO security attributes in @secattr.  Returns zero on
 * success and negative values on failure.
 *
 */
int cipso_v4_socket_getattr(const struct socket *sock,
			    struct netlbl_lsm_secattr *secattr)
{
	int ret_val;

	lock_sock(sock->sk);
	ret_val = cipso_v4_sock_getattr(sock->sk, secattr);
	release_sock(sock->sk);

	return ret_val;
}

/**
 * cipso_v4_skbuff_getattr - Get the security attributes from the CIPSO option
 * @skb: the packet
 * @secattr: the security attributes
 *
 * Description:
 * Parse the given packet's CIPSO option and return the security attributes.
 * Returns zero on success and negative values on failure.
 *
 */
int cipso_v4_skbuff_getattr(const struct sk_buff *skb,
			    struct netlbl_lsm_secattr *secattr)
{
	int ret_val = -ENOMSG;
	unsigned char *cipso_ptr;
	u32 doi;
	struct cipso_v4_doi *doi_def;

	cipso_ptr = CIPSO_V4_OPTPTR(skb);
	if (cipso_v4_cache_check(cipso_ptr, cipso_ptr[1], secattr) == 0)
		return 0;

	doi = ntohl(*(__be32 *)&cipso_ptr[2]);
	rcu_read_lock();
	doi_def = cipso_v4_doi_search(doi);
	if (doi_def == NULL)
		goto skbuff_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_ptr[6]) {
	case CIPSO_V4_TAG_RBITMAP:
		ret_val = cipso_v4_parsetag_rbm(doi_def,
						&cipso_ptr[6],
						secattr);
		break;
	case CIPSO_V4_TAG_ENUM:
		ret_val = cipso_v4_parsetag_enum(doi_def,
						 &cipso_ptr[6],
						 secattr);
		break;
	}

skbuff_getattr_return:
	rcu_read_unlock();
	return ret_val;
}

/*
 * 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);

Privacy Policy