aboutsummaryrefslogtreecommitdiff
path: root/sys/rpc/rpcsec_gss/svc_rpcsec_gss.c
blob: ed67eb1e8ae86093c753e6cf6ef47b6fd6b0ba20 (plain) (blame)
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
/*-
 * SPDX-License-Identifier: BSD-3-Clause
 * Copyright (c) 1990 The Regents of the University of California.
 *
 * Copyright (c) 2008 Doug Rabson
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
/*
  svc_rpcsec_gss.c
  
  Copyright (c) 2000 The Regents of the University of Michigan.
  All rights reserved.

  Copyright (c) 2000 Dug Song <dugsong@UMICH.EDU>.
  All rights reserved, all wrongs reversed.

  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions
  are met:

  1. Redistributions of source code must retain the above copyright
     notice, this list of conditions and the following disclaimer.
  2. Redistributions in binary form must reproduce the above copyright
     notice, this list of conditions and the following disclaimer in the
     documentation and/or other materials provided with the distribution.
  3. Neither the name of the University nor the names of its
     contributors may be used to endorse or promote products derived
     from this software without specific prior written permission.

  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

  $Id: svc_auth_gss.c,v 1.27 2002/01/15 15:43:00 andros Exp $
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/jail.h>
#include <sys/kernel.h>
#include <sys/kobj.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/sx.h>
#include <sys/ucred.h>

#include <rpc/rpc.h>
#include <rpc/rpcsec_gss.h>

#include "rpcsec_gss_int.h"

static bool_t   svc_rpc_gss_wrap(SVCAUTH *, struct mbuf **);
static bool_t   svc_rpc_gss_unwrap(SVCAUTH *, struct mbuf **);
static void     svc_rpc_gss_release(SVCAUTH *);
static enum auth_stat svc_rpc_gss(struct svc_req *, struct rpc_msg *);
static int rpc_gss_svc_getcred(struct svc_req *, struct ucred **, int *);

static struct svc_auth_ops svc_auth_gss_ops = {
	svc_rpc_gss_wrap,
	svc_rpc_gss_unwrap,
	svc_rpc_gss_release,
};

struct sx svc_rpc_gss_lock;

struct svc_rpc_gss_callback {
	SLIST_ENTRY(svc_rpc_gss_callback) cb_link;
	rpc_gss_callback_t	cb_callback;
};
static SLIST_HEAD(svc_rpc_gss_callback_list, svc_rpc_gss_callback)
	svc_rpc_gss_callbacks = SLIST_HEAD_INITIALIZER(svc_rpc_gss_callbacks);

struct svc_rpc_gss_svc_name {
	SLIST_ENTRY(svc_rpc_gss_svc_name) sn_link;
	char			*sn_principal;
	gss_OID			sn_mech;
	u_int			sn_req_time;
	gss_cred_id_t		sn_cred;
	u_int			sn_program;
	u_int			sn_version;
};
static SLIST_HEAD(svc_rpc_gss_svc_name_list, svc_rpc_gss_svc_name)
	svc_rpc_gss_svc_names = SLIST_HEAD_INITIALIZER(svc_rpc_gss_svc_names);

enum svc_rpc_gss_client_state {
	CLIENT_NEW,				/* still authenticating */
	CLIENT_ESTABLISHED,			/* context established */
	CLIENT_STALE				/* garbage to collect */
};

#define SVC_RPC_GSS_SEQWINDOW	128

struct svc_rpc_gss_clientid {
	unsigned long		ci_hostid;
	uint32_t		ci_boottime;
	uint32_t		ci_id;
};

struct svc_rpc_gss_client {
	TAILQ_ENTRY(svc_rpc_gss_client) cl_link;
	TAILQ_ENTRY(svc_rpc_gss_client) cl_alllink;
	volatile u_int		cl_refs;
	struct sx		cl_lock;
	struct svc_rpc_gss_clientid cl_id;
	time_t			cl_expiration;	/* when to gc */
	enum svc_rpc_gss_client_state cl_state;	/* client state */
	bool_t			cl_locked;	/* fixed service+qop */
	gss_ctx_id_t		cl_ctx;		/* context id */
	gss_cred_id_t		cl_creds;	/* delegated creds */
	gss_name_t		cl_cname;	/* client name */
	struct svc_rpc_gss_svc_name *cl_sname;	/* server name used */
	rpc_gss_rawcred_t	cl_rawcred;	/* raw credentials */
	rpc_gss_ucred_t		cl_ucred;	/* unix-style credentials */
	struct ucred		*cl_cred;	/* kernel-style credentials */
	int			cl_rpcflavor;	/* RPC pseudo sec flavor */
	bool_t			cl_done_callback; /* TRUE after call */
	void			*cl_cookie;	/* user cookie from callback */
	gid_t			cl_gid_storage[NGROUPS];
	gss_OID			cl_mech;	/* mechanism */
	gss_qop_t		cl_qop;		/* quality of protection */
	uint32_t		cl_seqlast;	/* sequence window origin */
	uint32_t		cl_seqmask[SVC_RPC_GSS_SEQWINDOW/32]; /* bitmask of seqnums */
};
TAILQ_HEAD(svc_rpc_gss_client_list, svc_rpc_gss_client);

/*
 * This structure holds enough information to unwrap arguments or wrap
 * results for a given request. We use the rq_clntcred area for this
 * (which is a per-request buffer).
 */
struct svc_rpc_gss_cookedcred {
	struct svc_rpc_gss_client *cc_client;
	rpc_gss_service_t	cc_service;
	uint32_t		cc_seq;
};

#define CLIENT_HASH_SIZE	256
#define CLIENT_MAX		1024
u_int svc_rpc_gss_client_max = CLIENT_MAX;
u_int svc_rpc_gss_client_hash_size = CLIENT_HASH_SIZE;

SYSCTL_NODE(_kern, OID_AUTO, rpc, CTLFLAG_RW, 0, "RPC");
SYSCTL_NODE(_kern_rpc, OID_AUTO, gss, CTLFLAG_RW, 0, "GSS");

SYSCTL_UINT(_kern_rpc_gss, OID_AUTO, client_max, CTLFLAG_RW,
    &svc_rpc_gss_client_max, 0,
    "Max number of rpc-gss clients");

SYSCTL_UINT(_kern_rpc_gss, OID_AUTO, client_hash, CTLFLAG_RDTUN,
    &svc_rpc_gss_client_hash_size, 0,
    "Size of rpc-gss client hash table");

static u_int svc_rpc_gss_lifetime_max = 0;
SYSCTL_UINT(_kern_rpc_gss, OID_AUTO, lifetime_max, CTLFLAG_RW,
    &svc_rpc_gss_lifetime_max, 0,
    "Maximum lifetime (seconds) of rpc-gss clients");

static u_int svc_rpc_gss_client_count;
SYSCTL_UINT(_kern_rpc_gss, OID_AUTO, client_count, CTLFLAG_RD,
    &svc_rpc_gss_client_count, 0,
    "Number of rpc-gss clients");

struct svc_rpc_gss_client_list *svc_rpc_gss_client_hash;
struct svc_rpc_gss_client_list svc_rpc_gss_clients;
static uint32_t svc_rpc_gss_next_clientid = 1;

static void
svc_rpc_gss_init(void *arg)
{
	int i;

	svc_rpc_gss_client_hash = mem_alloc(sizeof(struct svc_rpc_gss_client_list) * svc_rpc_gss_client_hash_size);
	for (i = 0; i < svc_rpc_gss_client_hash_size; i++)
		TAILQ_INIT(&svc_rpc_gss_client_hash[i]);
	TAILQ_INIT(&svc_rpc_gss_clients);
	svc_auth_reg(RPCSEC_GSS, svc_rpc_gss, rpc_gss_svc_getcred);
	sx_init(&svc_rpc_gss_lock, "gsslock");
}
SYSINIT(svc_rpc_gss_init, SI_SUB_KMEM, SI_ORDER_ANY, svc_rpc_gss_init, NULL);

bool_t
rpc_gss_set_callback(rpc_gss_callback_t *cb)
{
	struct svc_rpc_gss_callback *scb;

	scb = mem_alloc(sizeof(struct svc_rpc_gss_callback));
	if (!scb) {
		_rpc_gss_set_error(RPC_GSS_ER_SYSTEMERROR, ENOMEM);
		return (FALSE);
	}
	scb->cb_callback = *cb;
	sx_xlock(&svc_rpc_gss_lock);
	SLIST_INSERT_HEAD(&svc_rpc_gss_callbacks, scb, cb_link);
	sx_xunlock(&svc_rpc_gss_lock);

	return (TRUE);
}

void
rpc_gss_clear_callback(rpc_gss_callback_t *cb)
{
	struct svc_rpc_gss_callback *scb;

	sx_xlock(&svc_rpc_gss_lock);
	SLIST_FOREACH(scb, &svc_rpc_gss_callbacks, cb_link) {
		if (scb->cb_callback.program == cb->program
		    && scb->cb_callback.version == cb->version
		    && scb->cb_callback.callback == cb->callback) {
			SLIST_REMOVE(&svc_rpc_gss_callbacks, scb,
			    svc_rpc_gss_callback, cb_link);
			sx_xunlock(&svc_rpc_gss_lock);
			mem_free(scb, sizeof(*scb));
			return;
		}
	}
	sx_xunlock(&svc_rpc_gss_lock);
}

static bool_t
rpc_gss_acquire_svc_cred(struct svc_rpc_gss_svc_name *sname)
{
	OM_uint32		maj_stat, min_stat;
	gss_buffer_desc		namebuf;
	gss_name_t		name;
	gss_OID_set_desc	oid_set;

	oid_set.count = 1;
	oid_set.elements = sname->sn_mech;

	namebuf.value = (void *) sname->sn_principal;
	namebuf.length = strlen(sname->sn_principal);

	maj_stat = gss_import_name(&min_stat, &namebuf,
				   GSS_C_NT_HOSTBASED_SERVICE, &name);
	if (maj_stat != GSS_S_COMPLETE)
		return (FALSE);

	if (sname->sn_cred != GSS_C_NO_CREDENTIAL)
		gss_release_cred(&min_stat, &sname->sn_cred);

	maj_stat = gss_acquire_cred(&min_stat, name,
	    sname->sn_req_time, &oid_set, GSS_C_ACCEPT, &sname->sn_cred,
	    NULL, NULL);
	if (maj_stat != GSS_S_COMPLETE) {
		gss_release_name(&min_stat, &name);
		return (FALSE);
	}
	gss_release_name(&min_stat, &name);

	return (TRUE);
}

bool_t
rpc_gss_set_svc_name(const char *principal, const char *mechanism,
    u_int req_time, u_int program, u_int version)
{
	struct svc_rpc_gss_svc_name *sname;
	gss_OID			mech_oid;

	if (!rpc_gss_mech_to_oid(mechanism, &mech_oid))
		return (FALSE);

	sname = mem_alloc(sizeof(*sname));
	if (!sname)
		return (FALSE);
	sname->sn_principal = strdup(principal, M_RPC);
	sname->sn_mech = mech_oid;
	sname->sn_req_time = req_time;
	sname->sn_cred = GSS_C_NO_CREDENTIAL;
	sname->sn_program = program;
	sname->sn_version = version;

	if (!rpc_gss_acquire_svc_cred(sname)) {
		free(sname->sn_principal, M_RPC);
		mem_free(sname, sizeof(*sname));
		return (FALSE);
	}

	sx_xlock(&svc_rpc_gss_lock);
	SLIST_INSERT_HEAD(&svc_rpc_gss_svc_names, sname, sn_link);
	sx_xunlock(&svc_rpc_gss_lock);

	return (TRUE);
}

void
rpc_gss_clear_svc_name(u_int program, u_int version)
{
	OM_uint32		min_stat;
	struct svc_rpc_gss_svc_name *sname;

	sx_xlock(&svc_rpc_gss_lock);
	SLIST_FOREACH(sname, &svc_rpc_gss_svc_names, sn_link) {
		if (sname->sn_program == program
		    && sname->sn_version == version) {
			SLIST_REMOVE(&svc_rpc_gss_svc_names, sname,
			    svc_rpc_gss_svc_name, sn_link);
			sx_xunlock(&svc_rpc_gss_lock);
			gss_release_cred(&min_stat, &sname->sn_cred);
			free(sname->sn_principal, M_RPC);
			mem_free(sname, sizeof(*sname));
			return;
		}
	}
	sx_xunlock(&svc_rpc_gss_lock);
}

bool_t
rpc_gss_get_principal_name(rpc_gss_principal_t *principal,
    const char *mech, const char *name, const char *node, const char *domain)
{
	OM_uint32		maj_stat, min_stat;
	gss_OID			mech_oid;
	size_t			namelen;
	gss_buffer_desc		buf;
	gss_name_t		gss_name, gss_mech_name;
	rpc_gss_principal_t	result;

	if (!rpc_gss_mech_to_oid(mech, &mech_oid))
		return (FALSE);

	/*
	 * Construct a gss_buffer containing the full name formatted
	 * as "name/node@domain" where node and domain are optional.
	 */
	namelen = strlen(name) + 1;
	if (node) {
		namelen += strlen(node) + 1;
	}
	if (domain) {
		namelen += strlen(domain) + 1;
	}

	buf.value = mem_alloc(namelen);
	buf.length = namelen;
	strcpy((char *) buf.value, name);
	if (node) {
		strcat((char *) buf.value, "/");
		strcat((char *) buf.value, node);
	}
	if (domain) {
		strcat((char *) buf.value, "@");
		strcat((char *) buf.value, domain);
	}

	/*
	 * Convert that to a gss_name_t and then convert that to a
	 * mechanism name in the selected mechanism.
	 */
	maj_stat = gss_import_name(&min_stat, &buf,
	    GSS_C_NT_USER_NAME, &gss_name);
	mem_free(buf.value, buf.length);
	if (maj_stat != GSS_S_COMPLETE) {
		rpc_gss_log_status("gss_import_name", mech_oid, maj_stat, min_stat);
		return (FALSE);
	}
	maj_stat = gss_canonicalize_name(&min_stat, gss_name, mech_oid,
	    &gss_mech_name);
	if (maj_stat != GSS_S_COMPLETE) {
		rpc_gss_log_status("gss_canonicalize_name", mech_oid, maj_stat,
		    min_stat);
		gss_release_name(&min_stat, &gss_name);
		return (FALSE);
	}
	gss_release_name(&min_stat, &gss_name);

	/*
	 * Export the mechanism name and use that to construct the
	 * rpc_gss_principal_t result.
	 */
	maj_stat = gss_export_name(&min_stat, gss_mech_name, &buf);
	if (maj_stat != GSS_S_COMPLETE) {
		rpc_gss_log_status("gss_export_name", mech_oid, maj_stat, min_stat);
		gss_release_name(&min_stat, &gss_mech_name);
		return (FALSE);
	}
	gss_release_name(&min_stat, &gss_mech_name);

	result = mem_alloc(sizeof(int) + buf.length);
	if (!result) {
		gss_release_buffer(&min_stat, &buf);
		return (FALSE);
	}
	result->len = buf.length;
	memcpy(result->name, buf.value, buf.length);
	gss_release_buffer(&min_stat, &buf);

	*principal = result;
	return (TRUE);
}

bool_t
rpc_gss_getcred(struct svc_req *req, rpc_gss_rawcred_t **rcred,
    rpc_gss_ucred_t **ucred, void **cookie)
{
	struct svc_rpc_gss_cookedcred *cc;
	struct svc_rpc_gss_client *client;

	if (req->rq_cred.oa_flavor != RPCSEC_GSS)
		return (FALSE);

	cc = req->rq_clntcred;
	client = cc->cc_client;
	if (rcred)
		*rcred = &client->cl_rawcred;
	if (ucred)
		*ucred = &client->cl_ucred;
	if (cookie)
		*cookie = client->cl_cookie;
	return (TRUE);
}

/*
 * This simpler interface is used by svc_getcred to copy the cred data
 * into a kernel cred structure.
 */
static int
rpc_gss_svc_getcred(struct svc_req *req, struct ucred **crp, int *flavorp)
{
	struct ucred *cr;
	struct svc_rpc_gss_cookedcred *cc;
	struct svc_rpc_gss_client *client;
	rpc_gss_ucred_t *uc;

	if (req->rq_cred.oa_flavor != RPCSEC_GSS)
		return (FALSE);

	cc = req->rq_clntcred;
	client = cc->cc_client;

	if (flavorp)
		*flavorp = client->cl_rpcflavor;

	if (client->cl_cred) {
		*crp = crhold(client->cl_cred);
		return (TRUE);
	}

	uc = &client->cl_ucred;
	cr = client->cl_cred = crget();
	cr->cr_uid = cr->cr_ruid = cr->cr_svuid = uc->uid;
	cr->cr_rgid = cr->cr_svgid = uc->gid;
	crsetgroups(cr, uc->gidlen, uc->gidlist);
	cr->cr_prison = &prison0;
	prison_hold(cr->cr_prison);
	*crp = crhold(cr);

	return (TRUE);
}

int
rpc_gss_svc_max_data_length(struct svc_req *req, int max_tp_unit_len)
{
	struct svc_rpc_gss_cookedcred *cc = req->rq_clntcred;
	struct svc_rpc_gss_client *client = cc->cc_client;
	int			want_conf;
	OM_uint32		max;
	OM_uint32		maj_stat, min_stat;
	int			result;

	switch (client->cl_rawcred.service) {
	case rpc_gss_svc_none:
		return (max_tp_unit_len);
		break;

	case rpc_gss_svc_default:
	case rpc_gss_svc_integrity:
		want_conf = FALSE;
		break;

	case rpc_gss_svc_privacy:
		want_conf = TRUE;
		break;

	default:
		return (0);
	}

	maj_stat = gss_wrap_size_limit(&min_stat, client->cl_ctx, want_conf,
	    client->cl_qop, max_tp_unit_len, &max);

	if (maj_stat == GSS_S_COMPLETE) {
		result = (int) max;
		if (result < 0)
			result = 0;
		return (result);
	} else {
		rpc_gss_log_status("gss_wrap_size_limit", client->cl_mech,
		    maj_stat, min_stat);
		return (0);
	}
}

static struct svc_rpc_gss_client *
svc_rpc_gss_find_client(struct svc_rpc_gss_clientid *id)
{
	struct svc_rpc_gss_client *client;
	struct svc_rpc_gss_client_list *list;
	struct timeval boottime;
	unsigned long hostid;

	rpc_gss_log_debug("in svc_rpc_gss_find_client(%d)", id->ci_id);

	getcredhostid(curthread->td_ucred, &hostid);
	getboottime(&boottime);
	if (id->ci_hostid != hostid || id->ci_boottime != boottime.tv_sec)
		return (NULL);

	list = &svc_rpc_gss_client_hash[id->ci_id % svc_rpc_gss_client_hash_size];
	sx_xlock(&svc_rpc_gss_lock);
	TAILQ_FOREACH(client, list, cl_link) {
		if (client->cl_id.ci_id == id->ci_id) {
			/*
			 * Move this client to the front of the LRU
			 * list.
			 */
			TAILQ_REMOVE(&svc_rpc_gss_clients, client, cl_alllink);
			TAILQ_INSERT_HEAD(&svc_rpc_gss_clients, client,
			    cl_alllink);
			refcount_acquire(&client->cl_refs);
			break;
		}
	}
	sx_xunlock(&svc_rpc_gss_lock);

	return (client);
}

static struct svc_rpc_gss_client *
svc_rpc_gss_create_client(void)
{
	struct svc_rpc_gss_client *client;
	struct svc_rpc_gss_client_list *list;
	struct timeval boottime;
	unsigned long hostid;

	rpc_gss_log_debug("in svc_rpc_gss_create_client()");

	client = mem_alloc(sizeof(struct svc_rpc_gss_client));
	memset(client, 0, sizeof(struct svc_rpc_gss_client));

	/*
	 * Set the initial value of cl_refs to two.  One for the caller
	 * and the other to hold onto the client structure until it expires.
	 */
	refcount_init(&client->cl_refs, 2);
	sx_init(&client->cl_lock, "GSS-client");
	getcredhostid(curthread->td_ucred, &hostid);
	client->cl_id.ci_hostid = hostid;
	getboottime(&boottime);
	client->cl_id.ci_boottime = boottime.tv_sec;
	client->cl_id.ci_id = svc_rpc_gss_next_clientid++;

	/*
	 * Start the client off with a short expiration time. We will
	 * try to get a saner value from the client creds later.
	 */
	client->cl_state = CLIENT_NEW;
	client->cl_locked = FALSE;
	client->cl_expiration = time_uptime + 5*60;

	list = &svc_rpc_gss_client_hash[client->cl_id.ci_id % svc_rpc_gss_client_hash_size];
	sx_xlock(&svc_rpc_gss_lock);
	TAILQ_INSERT_HEAD(list, client, cl_link);
	TAILQ_INSERT_HEAD(&svc_rpc_gss_clients, client, cl_alllink);
	svc_rpc_gss_client_count++;
	sx_xunlock(&svc_rpc_gss_lock);
	return (client);
}

static void
svc_rpc_gss_destroy_client(struct svc_rpc_gss_client *client)
{
	OM_uint32 min_stat;

	rpc_gss_log_debug("in svc_rpc_gss_destroy_client()");

	if (client->cl_ctx)
		gss_delete_sec_context(&min_stat,
		    &client->cl_ctx, GSS_C_NO_BUFFER);

	if (client->cl_cname)
		gss_release_name(&min_stat, &client->cl_cname);

	if (client->cl_rawcred.client_principal)
		mem_free(client->cl_rawcred.client_principal,
		    sizeof(*client->cl_rawcred.client_principal)
		    + client->cl_rawcred.client_principal->len);

	if (client->cl_cred)
		crfree(client->cl_cred);

	sx_destroy(&client->cl_lock);
	mem_free(client, sizeof(*client));
}

/*
 * Drop a reference to a client and free it if that was the last reference.
 */
static void
svc_rpc_gss_release_client(struct svc_rpc_gss_client *client)
{

	if (!refcount_release(&client->cl_refs))
		return;
	svc_rpc_gss_destroy_client(client);
}

/*
 * Remove a client from our global lists.
 * Must be called with svc_rpc_gss_lock held.
 */
static void
svc_rpc_gss_forget_client_locked(struct svc_rpc_gss_client *client)
{
	struct svc_rpc_gss_client_list *list;

	sx_assert(&svc_rpc_gss_lock, SX_XLOCKED);
	list = &svc_rpc_gss_client_hash[client->cl_id.ci_id % svc_rpc_gss_client_hash_size];
	TAILQ_REMOVE(list, client, cl_link);
	TAILQ_REMOVE(&svc_rpc_gss_clients, client, cl_alllink);
	svc_rpc_gss_client_count--;
}

/*
 * Remove a client from our global lists and free it if we can.
 */
static void
svc_rpc_gss_forget_client(struct svc_rpc_gss_client *client)
{
	struct svc_rpc_gss_client_list *list;
	struct svc_rpc_gss_client *tclient;

	list = &svc_rpc_gss_client_hash[client->cl_id.ci_id % svc_rpc_gss_client_hash_size];
	sx_xlock(&svc_rpc_gss_lock);
	TAILQ_FOREACH(tclient, list, cl_link) {
		/*
		 * Make sure this client has not already been removed
		 * from the lists by svc_rpc_gss_forget_client() or
		 * svc_rpc_gss_forget_client_locked().
		 */
		if (client == tclient) {
			svc_rpc_gss_forget_client_locked(client);
			sx_xunlock(&svc_rpc_gss_lock);
			svc_rpc_gss_release_client(client);
			return;
		}
	}
	sx_xunlock(&svc_rpc_gss_lock);
}

static void
svc_rpc_gss_timeout_clients(void)
{
	struct svc_rpc_gss_client *client;
	time_t now = time_uptime;

	rpc_gss_log_debug("in svc_rpc_gss_timeout_clients()");

	/*
	 * First enforce the max client limit. We keep
	 * svc_rpc_gss_clients in LRU order.
	 */
	sx_xlock(&svc_rpc_gss_lock);
	client = TAILQ_LAST(&svc_rpc_gss_clients, svc_rpc_gss_client_list);
	while (svc_rpc_gss_client_count > svc_rpc_gss_client_max && client != NULL) {
		svc_rpc_gss_forget_client_locked(client);
		sx_xunlock(&svc_rpc_gss_lock);
		svc_rpc_gss_release_client(client);
		sx_xlock(&svc_rpc_gss_lock);
		client = TAILQ_LAST(&svc_rpc_gss_clients,
		    svc_rpc_gss_client_list);
	}
again:
	TAILQ_FOREACH(client, &svc_rpc_gss_clients, cl_alllink) {
		if (client->cl_state == CLIENT_STALE
		    || now > client->cl_expiration) {
			svc_rpc_gss_forget_client_locked(client);
			sx_xunlock(&svc_rpc_gss_lock);
			rpc_gss_log_debug("expiring client %p", client);
			svc_rpc_gss_release_client(client);
			sx_xlock(&svc_rpc_gss_lock);
			goto again;
		}
	}
	sx_xunlock(&svc_rpc_gss_lock);
}

#ifdef DEBUG
/*
 * OID<->string routines.  These are uuuuugly.
 */
static OM_uint32
gss_oid_to_str(OM_uint32 *minor_status, gss_OID oid, gss_buffer_t oid_str)
{
	char		numstr[128];
	unsigned long	number;
	int		numshift;
	size_t		string_length;
	size_t		i;
	unsigned char	*cp;
	char		*bp;

	/* Decoded according to krb5/gssapi_krb5.c */

	/* First determine the size of the string */
	string_length = 0;
	number = 0;
	numshift = 0;
	cp = (unsigned char *) oid->elements;
	number = (unsigned long) cp[0];
	sprintf(numstr, "%ld ", number/40);
	string_length += strlen(numstr);
	sprintf(numstr, "%ld ", number%40);
	string_length += strlen(numstr);
	for (i=1; i<oid->length; i++) {
		if ( (size_t) (numshift+7) < (sizeof(unsigned long)*8)) {
			number = (number << 7) | (cp[i] & 0x7f);
			numshift += 7;
		}
		else {
			*minor_status = 0;
			return(GSS_S_FAILURE);
		}
		if ((cp[i] & 0x80) == 0) {
			sprintf(numstr, "%ld ", number);
			string_length += strlen(numstr);
			number = 0;
			numshift = 0;
		}
	}
	/*
	 * If we get here, we've calculated the length of "n n n ... n ".  Add 4
	 * here for "{ " and "}\0".
	 */
	string_length += 4;
	if ((bp = malloc(string_length, M_GSSAPI, M_WAITOK | M_ZERO))) {
		strcpy(bp, "{ ");
		number = (unsigned long) cp[0];
		sprintf(numstr, "%ld ", number/40);
		strcat(bp, numstr);
		sprintf(numstr, "%ld ", number%40);
		strcat(bp, numstr);
		number = 0;
		cp = (unsigned char *) oid->elements;
		for (i=1; i<oid->length; i++) {
			number = (number << 7) | (cp[i] & 0x7f);
			if ((cp[i] & 0x80) == 0) {
				sprintf(numstr, "%ld ", number);
				strcat(bp, numstr);
				number = 0;
			}
		}
		strcat(bp, "}");
		oid_str->length = strlen(bp)+1;
		oid_str->value = (void *) bp;
		*minor_status = 0;
		return(GSS_S_COMPLETE);
	}
	*minor_status = 0;
	return(GSS_S_FAILURE);
}
#endif

static void
svc_rpc_gss_build_ucred(struct svc_rpc_gss_client *client,
    const gss_name_t name)
{
	OM_uint32		maj_stat, min_stat;
	rpc_gss_ucred_t		*uc = &client->cl_ucred;
	int			numgroups;

	uc->uid = 65534;
	uc->gid = 65534;
	uc->gidlist = client->cl_gid_storage;

	numgroups = NGROUPS;
	maj_stat = gss_pname_to_unix_cred(&min_stat, name, client->cl_mech,
	    &uc->uid, &uc->gid, &numgroups, &uc->gidlist[0]);
	if (GSS_ERROR(maj_stat))
		uc->gidlen = 0;
	else
		uc->gidlen = numgroups;
}

static void
svc_rpc_gss_set_flavor(struct svc_rpc_gss_client *client)
{
	static gss_OID_desc krb5_mech_oid =
		{9, (void *) "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02" };

	/*
	 * Attempt to translate mech type and service into a
	 * 'pseudo flavor'. Hardwire in krb5 support for now.
	 */
	if (kgss_oid_equal(client->cl_mech, &krb5_mech_oid)) {
		switch (client->cl_rawcred.service) {
		case rpc_gss_svc_default:
		case rpc_gss_svc_none:
			client->cl_rpcflavor = RPCSEC_GSS_KRB5;
			break;
		case rpc_gss_svc_integrity:
			client->cl_rpcflavor = RPCSEC_GSS_KRB5I;
			break;
		case rpc_gss_svc_privacy:
			client->cl_rpcflavor = RPCSEC_GSS_KRB5P;
			break;
		}
	} else {
		client->cl_rpcflavor = RPCSEC_GSS;
	}
}

static bool_t
svc_rpc_gss_accept_sec_context(struct svc_rpc_gss_client *client,
			       struct svc_req *rqst,
			       struct rpc_gss_init_res *gr,
			       struct rpc_gss_cred *gc)
{
	gss_buffer_desc		recv_tok;
	gss_OID			mech;
	OM_uint32		maj_stat = 0, min_stat = 0, ret_flags;
	OM_uint32		cred_lifetime;
	struct svc_rpc_gss_svc_name *sname;

	rpc_gss_log_debug("in svc_rpc_gss_accept_context()");
	
	/* Deserialize arguments. */
	memset(&recv_tok, 0, sizeof(recv_tok));
	
	if (!svc_getargs(rqst,
		(xdrproc_t) xdr_gss_buffer_desc,
		(caddr_t) &recv_tok)) {
		client->cl_state = CLIENT_STALE;
		return (FALSE);
	}

	/*
	 * First time round, try all the server names we have until
	 * one matches. Afterwards, stick with that one.
	 */
	sx_xlock(&svc_rpc_gss_lock);
	if (!client->cl_sname) {
		SLIST_FOREACH(sname, &svc_rpc_gss_svc_names, sn_link) {
			if (sname->sn_program == rqst->rq_prog
			    && sname->sn_version == rqst->rq_vers) {
			retry:
				gr->gr_major = gss_accept_sec_context(
					&gr->gr_minor,
					&client->cl_ctx,
					sname->sn_cred,
					&recv_tok,
					GSS_C_NO_CHANNEL_BINDINGS,
					&client->cl_cname,
					&mech,
					&gr->gr_token,
					&ret_flags,
					&cred_lifetime,
					&client->cl_creds);
				if (gr->gr_major == 
				    GSS_S_CREDENTIALS_EXPIRED) {
					/*
					 * Either our creds really did
					 * expire or gssd was
					 * restarted.
					 */
					if (rpc_gss_acquire_svc_cred(sname))
						goto retry;
				}
				client->cl_sname = sname;
				break;
			}
		}
		if (!sname) {
			xdr_free((xdrproc_t) xdr_gss_buffer_desc,
			    (char *) &recv_tok);
			sx_xunlock(&svc_rpc_gss_lock);
			return (FALSE);
		}
	} else {
		gr->gr_major = gss_accept_sec_context(
			&gr->gr_minor,
			&client->cl_ctx,
			client->cl_sname->sn_cred,
			&recv_tok,
			GSS_C_NO_CHANNEL_BINDINGS,
			&client->cl_cname,
			&mech,
			&gr->gr_token,
			&ret_flags,
			&cred_lifetime,
			NULL);
	}
	sx_xunlock(&svc_rpc_gss_lock);
	
	xdr_free((xdrproc_t) xdr_gss_buffer_desc, (char *) &recv_tok);

	/*
	 * If we get an error from gss_accept_sec_context, send the
	 * reply anyway so that the client gets a chance to see what
	 * is wrong.
	 */
	if (gr->gr_major != GSS_S_COMPLETE &&
	    gr->gr_major != GSS_S_CONTINUE_NEEDED) {
		rpc_gss_log_status("accept_sec_context", client->cl_mech,
		    gr->gr_major, gr->gr_minor);
		client->cl_state = CLIENT_STALE;
		return (TRUE);
	}

	gr->gr_handle.value = &client->cl_id;
	gr->gr_handle.length = sizeof(client->cl_id);
	gr->gr_win = SVC_RPC_GSS_SEQWINDOW;
	
	/* Save client info. */
	client->cl_mech = mech;
	client->cl_qop = GSS_C_QOP_DEFAULT;
	client->cl_done_callback = FALSE;

	if (gr->gr_major == GSS_S_COMPLETE) {
		gss_buffer_desc	export_name;

		/*
		 * Change client expiration time to be near when the
		 * client creds expire (or 24 hours if we can't figure
		 * that out).
		 */
		if (cred_lifetime == GSS_C_INDEFINITE)
			cred_lifetime = 24*60*60;

		/*
		 * Cap cred_lifetime if sysctl kern.rpc.gss.lifetime_max is set.
		 */
		if (svc_rpc_gss_lifetime_max > 0 && cred_lifetime >
		    svc_rpc_gss_lifetime_max)
			cred_lifetime = svc_rpc_gss_lifetime_max;
		
		client->cl_expiration = time_uptime + cred_lifetime;

		/*
		 * Fill in cred details in the rawcred structure.
		 */
		client->cl_rawcred.version = RPCSEC_GSS_VERSION;
		rpc_gss_oid_to_mech(mech, &client->cl_rawcred.mechanism);
		maj_stat = gss_export_name(&min_stat, client->cl_cname,
		    &export_name);
		if (maj_stat != GSS_S_COMPLETE) {
			rpc_gss_log_status("gss_export_name", client->cl_mech,
			    maj_stat, min_stat);
			return (FALSE);
		}
		client->cl_rawcred.client_principal =
			mem_alloc(sizeof(*client->cl_rawcred.client_principal)
			    + export_name.length);
		client->cl_rawcred.client_principal->len = export_name.length;
		memcpy(client->cl_rawcred.client_principal->name,
		    export_name.value, export_name.length);
		gss_release_buffer(&min_stat, &export_name);
		client->cl_rawcred.svc_principal =
			client->cl_sname->sn_principal;
		client->cl_rawcred.service = gc->gc_svc;

		/*
		 * Use gss_pname_to_uid to map to unix creds. For
		 * kerberos5, this uses krb5_aname_to_localname.
		 */
		svc_rpc_gss_build_ucred(client, client->cl_cname);
		svc_rpc_gss_set_flavor(client);
		gss_release_name(&min_stat, &client->cl_cname);

#ifdef DEBUG
		{
			gss_buffer_desc mechname;

			gss_oid_to_str(&min_stat, mech, &mechname);
			
			rpc_gss_log_debug("accepted context for %s with "
			    "<mech %.*s, qop %d, svc %d>",
			    client->cl_rawcred.client_principal->name,
			    mechname.length, (char *)mechname.value,
			    client->cl_qop, client->cl_rawcred.service);

			gss_release_buffer(&min_stat, &mechname);
		}
#endif /* DEBUG */
	}
	return (TRUE);
}

static bool_t
svc_rpc_gss_validate(struct svc_rpc_gss_client *client, struct rpc_msg *msg,
    gss_qop_t *qop, rpc_gss_proc_t gcproc)
{
	struct opaque_auth	*oa;
	gss_buffer_desc		 rpcbuf, checksum;
	OM_uint32		 maj_stat, min_stat;
	gss_qop_t		 qop_state;
	int32_t			 rpchdr[128 / sizeof(int32_t)];
	int32_t			*buf;

	rpc_gss_log_debug("in svc_rpc_gss_validate()");
	
	memset(rpchdr, 0, sizeof(rpchdr));

	/* Reconstruct RPC header for signing (from xdr_callmsg). */
	buf = rpchdr;
	IXDR_PUT_LONG(buf, msg->rm_xid);
	IXDR_PUT_ENUM(buf, msg->rm_direction);
	IXDR_PUT_LONG(buf, msg->rm_call.cb_rpcvers);
	IXDR_PUT_LONG(buf, msg->rm_call.cb_prog);
	IXDR_PUT_LONG(buf, msg->rm_call.cb_vers);
	IXDR_PUT_LONG(buf, msg->rm_call.cb_proc);
	oa = &msg->rm_call.cb_cred;
	IXDR_PUT_ENUM(buf, oa->oa_flavor);
	IXDR_PUT_LONG(buf, oa->oa_length);
	if (oa->oa_length) {
		memcpy((caddr_t)buf, oa->oa_base, oa->oa_length);
		buf += RNDUP(oa->oa_length) / sizeof(int32_t);
	}
	rpcbuf.value = rpchdr;
	rpcbuf.length = (u_char *)buf - (u_char *)rpchdr;

	checksum.value = msg->rm_call.cb_verf.oa_base;
	checksum.length = msg->rm_call.cb_verf.oa_length;
	
	maj_stat = gss_verify_mic(&min_stat, client->cl_ctx, &rpcbuf, &checksum,
				  &qop_state);
	
	if (maj_stat != GSS_S_COMPLETE) {
		rpc_gss_log_status("gss_verify_mic", client->cl_mech,
		    maj_stat, min_stat);
		/*
		 * A bug in some versions of the Linux client generates a
		 * Destroy operation with a bogus encrypted checksum. Deleting
		 * the credential handle for that case causes the mount to fail.
		 * Since the checksum is bogus (gss_verify_mic() failed), it
		 * doesn't make sense to destroy the handle and not doing so
		 * fixes the Linux mount.
		 */
		if (gcproc != RPCSEC_GSS_DESTROY)
			client->cl_state = CLIENT_STALE;
		return (FALSE);
	}

	*qop = qop_state;
	return (TRUE);
}

static bool_t
svc_rpc_gss_nextverf(struct svc_rpc_gss_client *client,
    struct svc_req *rqst, u_int seq)
{
	gss_buffer_desc		signbuf;
	gss_buffer_desc		mic;
	OM_uint32		maj_stat, min_stat;
	uint32_t		nseq;       

	rpc_gss_log_debug("in svc_rpc_gss_nextverf()");

	nseq = htonl(seq);
	signbuf.value = &nseq;
	signbuf.length = sizeof(nseq);

	maj_stat = gss_get_mic(&min_stat, client->cl_ctx, client->cl_qop,
	    &signbuf, &mic);

	if (maj_stat != GSS_S_COMPLETE) {
		rpc_gss_log_status("gss_get_mic", client->cl_mech, maj_stat, min_stat);
		client->cl_state = CLIENT_STALE;
		return (FALSE);
	}

	KASSERT(mic.length <= MAX_AUTH_BYTES,
	    ("MIC too large for RPCSEC_GSS"));

	rqst->rq_verf.oa_flavor = RPCSEC_GSS;
	rqst->rq_verf.oa_length = mic.length;
	bcopy(mic.value, rqst->rq_verf.oa_base, mic.length);

	gss_release_buffer(&min_stat, &mic);
	
	return (TRUE);
}

static bool_t
svc_rpc_gss_callback(struct svc_rpc_gss_client *client, struct svc_req *rqst)
{
	struct svc_rpc_gss_callback *scb;
	rpc_gss_lock_t	lock;
	void		*cookie;
	bool_t		cb_res;
	bool_t		result;

	/*
	 * See if we have a callback for this guy.
	 */
	result = TRUE;
	SLIST_FOREACH(scb, &svc_rpc_gss_callbacks, cb_link) {
		if (scb->cb_callback.program == rqst->rq_prog
		    && scb->cb_callback.version == rqst->rq_vers) {
			/*
			 * This one matches. Call the callback and see
			 * if it wants to veto or something.
			 */
			lock.locked = FALSE;
			lock.raw_cred = &client->cl_rawcred;
			cb_res = scb->cb_callback.callback(rqst,
			    client->cl_creds,
			    client->cl_ctx,
			    &lock,
			    &cookie);

			if (!cb_res) {
				client->cl_state = CLIENT_STALE;
				result = FALSE;
				break;
			}

			/*
			 * The callback accepted the connection - it
			 * is responsible for freeing client->cl_creds
			 * now.
			 */
			client->cl_creds = GSS_C_NO_CREDENTIAL;
			client->cl_locked = lock.locked;
			client->cl_cookie = cookie;
			return (TRUE);
		}
	}

	/*
	 * Either no callback exists for this program/version or one
	 * of the callbacks rejected the connection. We just need to
	 * clean up the delegated client creds, if any.
	 */
	if (client->cl_creds) {
		OM_uint32 min_ver;
		gss_release_cred(&min_ver, &client->cl_creds);
	}
	return (result);
}

static bool_t
svc_rpc_gss_check_replay(struct svc_rpc_gss_client *client, uint32_t seq)
{
	u_int32_t offset;
	int word, bit;
	bool_t result;

	sx_xlock(&client->cl_lock);
	if (seq <= client->cl_seqlast) {
		/*
		 * The request sequence number is less than
		 * the largest we have seen so far. If it is
		 * outside the window or if we have seen a
		 * request with this sequence before, silently
		 * discard it.
		 */
		offset = client->cl_seqlast - seq;
		if (offset >= SVC_RPC_GSS_SEQWINDOW) {
			result = FALSE;
			goto out;
		}
		word = offset / 32;
		bit = offset % 32;
		if (client->cl_seqmask[word] & (1 << bit)) {
			result = FALSE;
			goto out;
		}
	}

	result = TRUE;
out:
	sx_xunlock(&client->cl_lock);
	return (result);
}

static void
svc_rpc_gss_update_seq(struct svc_rpc_gss_client *client, uint32_t seq)
{
	int offset, i, word, bit;
	uint32_t carry, newcarry;

	sx_xlock(&client->cl_lock);
	if (seq > client->cl_seqlast) {
		/*
		 * This request has a sequence number greater
		 * than any we have seen so far. Advance the
		 * seq window and set bit zero of the window
		 * (which corresponds to the new sequence
		 * number)
		 */
		offset = seq - client->cl_seqlast;
		while (offset > 32) {
			for (i = (SVC_RPC_GSS_SEQWINDOW / 32) - 1;
			     i > 0; i--) {
				client->cl_seqmask[i] = client->cl_seqmask[i-1];
			}
			client->cl_seqmask[0] = 0;
			offset -= 32;
		}
		carry = 0;
		for (i = 0; i < SVC_RPC_GSS_SEQWINDOW / 32; i++) {
			newcarry = client->cl_seqmask[i] >> (32 - offset);
			client->cl_seqmask[i] =
				(client->cl_seqmask[i] << offset) | carry;
			carry = newcarry;
		}
		client->cl_seqmask[0] |= 1;
		client->cl_seqlast = seq;
	} else {
		offset = client->cl_seqlast - seq;
		word = offset / 32;
		bit = offset % 32;
		client->cl_seqmask[word] |= (1 << bit);
	}
	sx_xunlock(&client->cl_lock);
}

enum auth_stat
svc_rpc_gss(struct svc_req *rqst, struct rpc_msg *msg)

{
	OM_uint32		 min_stat;
	XDR	 		 xdrs;
	struct svc_rpc_gss_cookedcred *cc;
	struct svc_rpc_gss_client *client;
	struct rpc_gss_cred	 gc;
	struct rpc_gss_init_res	 gr;
	gss_qop_t		 qop;
	int			 call_stat;
	enum auth_stat		 result;
	
	rpc_gss_log_debug("in svc_rpc_gss()");
	
	/* Garbage collect old clients. */
	svc_rpc_gss_timeout_clients();

	/* Initialize reply. */
	rqst->rq_verf = _null_auth;

	/* Deserialize client credentials. */
	if (rqst->rq_cred.oa_length <= 0)
		return (AUTH_BADCRED);
	
	memset(&gc, 0, sizeof(gc));
	
	xdrmem_create(&xdrs, rqst->rq_cred.oa_base,
	    rqst->rq_cred.oa_length, XDR_DECODE);
	
	if (!xdr_rpc_gss_cred(&xdrs, &gc)) {
		XDR_DESTROY(&xdrs);
		return (AUTH_BADCRED);
	}
	XDR_DESTROY(&xdrs);

	client = NULL;

	/* Check version. */
	if (gc.gc_version != RPCSEC_GSS_VERSION) {
		result = AUTH_BADCRED;
		goto out;
	}

	/* Check the proc and find the client (or create it) */
	if (gc.gc_proc == RPCSEC_GSS_INIT) {
		if (gc.gc_handle.length != 0) {
			result = AUTH_BADCRED;
			goto out;
		}
		client = svc_rpc_gss_create_client();
	} else {
		struct svc_rpc_gss_clientid *p;
		if (gc.gc_handle.length != sizeof(*p)) {
			result = AUTH_BADCRED;
			goto out;
		}
		p = gc.gc_handle.value;
		client = svc_rpc_gss_find_client(p);
		if (!client) {
			/*
			 * Can't find the client - we may have
			 * destroyed it - tell the other side to
			 * re-authenticate.
			 */
			result = RPCSEC_GSS_CREDPROBLEM;
			goto out;
		}
	}
	cc = rqst->rq_clntcred;
	cc->cc_client = client;
	cc->cc_service = gc.gc_svc;
	cc->cc_seq = gc.gc_seq;

	/*
	 * The service and sequence number must be ignored for
	 * RPCSEC_GSS_INIT and RPCSEC_GSS_CONTINUE_INIT.
	 */
	if (gc.gc_proc != RPCSEC_GSS_INIT
	    && gc.gc_proc != RPCSEC_GSS_CONTINUE_INIT) {
		/*
		 * Check for sequence number overflow.
		 */
		if (gc.gc_seq >= MAXSEQ) {
			result = RPCSEC_GSS_CTXPROBLEM;
			goto out;
		}

		/*
		 * Check for valid service.
		 */
		if (gc.gc_svc != rpc_gss_svc_none &&
		    gc.gc_svc != rpc_gss_svc_integrity &&
		    gc.gc_svc != rpc_gss_svc_privacy) {
			result = AUTH_BADCRED;
			goto out;
		}
	}

	/* Handle RPCSEC_GSS control procedure. */
	switch (gc.gc_proc) {

	case RPCSEC_GSS_INIT:
	case RPCSEC_GSS_CONTINUE_INIT:
		if (rqst->rq_proc != NULLPROC) {
			result = AUTH_REJECTEDCRED;
			break;
		}

		memset(&gr, 0, sizeof(gr));
		if (!svc_rpc_gss_accept_sec_context(client, rqst, &gr, &gc)) {
			result = AUTH_REJECTEDCRED;
			break;
		}

		if (gr.gr_major == GSS_S_COMPLETE) {
			/*
			 * We borrow the space for the call verf to
			 * pack our reply verf.
			 */
			rqst->rq_verf = msg->rm_call.cb_verf;
			if (!svc_rpc_gss_nextverf(client, rqst, gr.gr_win)) {
				result = AUTH_REJECTEDCRED;
				break;
			}
		} else {
			rqst->rq_verf = _null_auth;
		}
		
		call_stat = svc_sendreply(rqst,
		    (xdrproc_t) xdr_rpc_gss_init_res,
		    (caddr_t) &gr);

		gss_release_buffer(&min_stat, &gr.gr_token);

		if (!call_stat) {
			result = AUTH_FAILED;
			break;
		}

		if (gr.gr_major == GSS_S_COMPLETE)
			client->cl_state = CLIENT_ESTABLISHED;

		result = RPCSEC_GSS_NODISPATCH;
		break;
		
	case RPCSEC_GSS_DATA:
	case RPCSEC_GSS_DESTROY:
		if (!svc_rpc_gss_check_replay(client, gc.gc_seq)) {
			result = RPCSEC_GSS_NODISPATCH;
			break;
		}

		if (!svc_rpc_gss_validate(client, msg, &qop, gc.gc_proc)) {
			result = RPCSEC_GSS_CREDPROBLEM;
			break;
		}
		
		/*
		 * We borrow the space for the call verf to pack our
		 * reply verf.
		 */
		rqst->rq_verf = msg->rm_call.cb_verf;
		if (!svc_rpc_gss_nextverf(client, rqst, gc.gc_seq)) {
			result = RPCSEC_GSS_CTXPROBLEM;
			break;
		}

		svc_rpc_gss_update_seq(client, gc.gc_seq);

		/*
		 * Change the SVCAUTH ops on the request to point at
		 * our own code so that we can unwrap the arguments
		 * and wrap the result. The caller will re-set this on
		 * every request to point to a set of null wrap/unwrap
		 * methods. Acquire an extra reference to the client
		 * which will be released by svc_rpc_gss_release()
		 * after the request has finished processing.
		 */
		refcount_acquire(&client->cl_refs);
		rqst->rq_auth.svc_ah_ops = &svc_auth_gss_ops;
		rqst->rq_auth.svc_ah_private = cc;

		if (gc.gc_proc == RPCSEC_GSS_DATA) {
			/*
			 * We might be ready to do a callback to the server to
			 * see if it wants to accept/reject the connection.
			 */
			sx_xlock(&client->cl_lock);
			if (!client->cl_done_callback) {
				client->cl_done_callback = TRUE;
				client->cl_qop = qop;
				client->cl_rawcred.qop = _rpc_gss_num_to_qop(
					client->cl_rawcred.mechanism, qop);
				if (!svc_rpc_gss_callback(client, rqst)) {
					result = AUTH_REJECTEDCRED;
					sx_xunlock(&client->cl_lock);
					break;
				}
			}
			sx_xunlock(&client->cl_lock);

			/*
			 * If the server has locked this client to a
			 * particular service+qop pair, enforce that
			 * restriction now.
			 */
			if (client->cl_locked) {
				if (client->cl_rawcred.service != gc.gc_svc) {
					result = AUTH_FAILED;
					break;
				} else if (client->cl_qop != qop) {
					result = AUTH_BADVERF;
					break;
				}
			}

			/*
			 * If the qop changed, look up the new qop
			 * name for rawcred.
			 */
			if (client->cl_qop != qop) {
				client->cl_qop = qop;
				client->cl_rawcred.qop = _rpc_gss_num_to_qop(
					client->cl_rawcred.mechanism, qop);
			}

			/*
			 * Make sure we use the right service value
			 * for unwrap/wrap.
			 */
			if (client->cl_rawcred.service != gc.gc_svc) {
				client->cl_rawcred.service = gc.gc_svc;
				svc_rpc_gss_set_flavor(client);
			}

			result = AUTH_OK;
		} else {
			if (rqst->rq_proc != NULLPROC) {
				result = AUTH_REJECTEDCRED;
				break;
			}

			call_stat = svc_sendreply(rqst,
			    (xdrproc_t) xdr_void, (caddr_t) NULL);

			if (!call_stat) {
				result = AUTH_FAILED;
				break;
			}

			svc_rpc_gss_forget_client(client);

			result = RPCSEC_GSS_NODISPATCH;
			break;
		}
		break;

	default:
		result = AUTH_BADCRED;
		break;
	}
out:
	if (client)
		svc_rpc_gss_release_client(client);

	xdr_free((xdrproc_t) xdr_rpc_gss_cred, (char *) &gc);
	return (result);
}

static bool_t
svc_rpc_gss_wrap(SVCAUTH *auth, struct mbuf **mp)
{
	struct svc_rpc_gss_cookedcred *cc;
	struct svc_rpc_gss_client *client;
	
	rpc_gss_log_debug("in svc_rpc_gss_wrap()");

	cc = (struct svc_rpc_gss_cookedcred *) auth->svc_ah_private;
	client = cc->cc_client;
	if (client->cl_state != CLIENT_ESTABLISHED
	    || cc->cc_service == rpc_gss_svc_none || *mp == NULL) {
		return (TRUE);
	}
	
	return (xdr_rpc_gss_wrap_data(mp,
		client->cl_ctx, client->cl_qop,
		cc->cc_service, cc->cc_seq));
}

static bool_t
svc_rpc_gss_unwrap(SVCAUTH *auth, struct mbuf **mp)
{
	struct svc_rpc_gss_cookedcred *cc;
	struct svc_rpc_gss_client *client;

	rpc_gss_log_debug("in svc_rpc_gss_unwrap()");
	
	cc = (struct svc_rpc_gss_cookedcred *) auth->svc_ah_private;
	client = cc->cc_client;
	if (client->cl_state != CLIENT_ESTABLISHED
	    || cc->cc_service == rpc_gss_svc_none) {
		return (TRUE);
	}

	return (xdr_rpc_gss_unwrap_data(mp,
		client->cl_ctx, client->cl_qop,
		cc->cc_service, cc->cc_seq));
}

static void
svc_rpc_gss_release(SVCAUTH *auth)
{
	struct svc_rpc_gss_cookedcred *cc;
	struct svc_rpc_gss_client *client;

	rpc_gss_log_debug("in svc_rpc_gss_release()");

	cc = (struct svc_rpc_gss_cookedcred *) auth->svc_ah_private;
	client = cc->cc_client;
	svc_rpc_gss_release_client(client);
}