summaryrefslogtreecommitdiff
path: root/net/sunrpc/auth_gss/svcauth_gss.c
blob: 73a90ad873fb9da659ba76184b2e2a0e5324ce0d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
// SPDX-License-Identifier: GPL-2.0
/*
 * Neil Brown <neilb@cse.unsw.edu.au>
 * J. Bruce Fields <bfields@umich.edu>
 * Andy Adamson <andros@umich.edu>
 * Dug Song <dugsong@monkey.org>
 *
 * RPCSEC_GSS server authentication.
 * This implements RPCSEC_GSS as defined in rfc2203 (rpcsec_gss) and rfc2078
 * (gssapi)
 *
 * The RPCSEC_GSS involves three stages:
 *  1/ context creation
 *  2/ data exchange
 *  3/ context destruction
 *
 * Context creation is handled largely by upcalls to user-space.
 *  In particular, GSS_Accept_sec_context is handled by an upcall
 * Data exchange is handled entirely within the kernel
 *  In particular, GSS_GetMIC, GSS_VerifyMIC, GSS_Seal, GSS_Unseal are in-kernel.
 * Context destruction is handled in-kernel
 *  GSS_Delete_sec_context is in-kernel
 *
 * Context creation is initiated by a RPCSEC_GSS_INIT request arriving.
 * The context handle and gss_token are used as a key into the rpcsec_init cache.
 * The content of this cache includes some of the outputs of GSS_Accept_sec_context,
 * being major_status, minor_status, context_handle, reply_token.
 * These are sent back to the client.
 * Sequence window management is handled by the kernel.  The window size if currently
 * a compile time constant.
 *
 * When user-space is happy that a context is established, it places an entry
 * in the rpcsec_context cache. The key for this cache is the context_handle.
 * The content includes:
 *   uid/gidlist - for determining access rights
 *   mechanism type
 *   mechanism specific information, such as a key
 *
 */

#include <linux/slab.h>
#include <linux/types.h>
#include <linux/module.h>
#include <linux/pagemap.h>
#include <linux/user_namespace.h>

#include <linux/sunrpc/auth_gss.h>
#include <linux/sunrpc/gss_err.h>
#include <linux/sunrpc/svcauth.h>
#include <linux/sunrpc/svcauth_gss.h>
#include <linux/sunrpc/cache.h>
#include <linux/sunrpc/gss_krb5.h>

#include <trace/events/rpcgss.h>

#include "gss_rpc_upcall.h"

/*
 * Unfortunately there isn't a maximum checksum size exported via the
 * GSS API. Manufacture one based on GSS mechanisms supported by this
 * implementation.
 */
#define GSS_MAX_CKSUMSIZE (GSS_KRB5_TOK_HDR_LEN + GSS_KRB5_MAX_CKSUM_LEN)

/*
 * This value may be increased in the future to accommodate other
 * usage of the scratch buffer.
 */
#define GSS_SCRATCH_SIZE GSS_MAX_CKSUMSIZE

struct gss_svc_data {
	/* decoded gss client cred: */
	struct rpc_gss_wire_cred	clcred;
	u32				gsd_databody_offset;
	struct rsc			*rsci;

	/* for temporary results */
	__be32				gsd_seq_num;
	u8				gsd_scratch[GSS_SCRATCH_SIZE];
};

/* The rpcsec_init cache is used for mapping RPCSEC_GSS_{,CONT_}INIT requests
 * into replies.
 *
 * Key is context handle (\x if empty) and gss_token.
 * Content is major_status minor_status (integers) context_handle, reply_token.
 *
 */

static int netobj_equal(struct xdr_netobj *a, struct xdr_netobj *b)
{
	return a->len == b->len && 0 == memcmp(a->data, b->data, a->len);
}

#define	RSI_HASHBITS	6
#define	RSI_HASHMAX	(1<<RSI_HASHBITS)

struct rsi {
	struct cache_head	h;
	struct xdr_netobj	in_handle, in_token;
	struct xdr_netobj	out_handle, out_token;
	int			major_status, minor_status;
	struct rcu_head		rcu_head;
};

static struct rsi *rsi_update(struct cache_detail *cd, struct rsi *new, struct rsi *old);
static struct rsi *rsi_lookup(struct cache_detail *cd, struct rsi *item);

static void rsi_free(struct rsi *rsii)
{
	kfree(rsii->in_handle.data);
	kfree(rsii->in_token.data);
	kfree(rsii->out_handle.data);
	kfree(rsii->out_token.data);
}

static void rsi_free_rcu(struct rcu_head *head)
{
	struct rsi *rsii = container_of(head, struct rsi, rcu_head);

	rsi_free(rsii);
	kfree(rsii);
}

static void rsi_put(struct kref *ref)
{
	struct rsi *rsii = container_of(ref, struct rsi, h.ref);

	call_rcu(&rsii->rcu_head, rsi_free_rcu);
}

static inline int rsi_hash(struct rsi *item)
{
	return hash_mem(item->in_handle.data, item->in_handle.len, RSI_HASHBITS)
	     ^ hash_mem(item->in_token.data, item->in_token.len, RSI_HASHBITS);
}

static int rsi_match(struct cache_head *a, struct cache_head *b)
{
	struct rsi *item = container_of(a, struct rsi, h);
	struct rsi *tmp = container_of(b, struct rsi, h);
	return netobj_equal(&item->in_handle, &tmp->in_handle) &&
	       netobj_equal(&item->in_token, &tmp->in_token);
}

static int dup_to_netobj(struct xdr_netobj *dst, char *src, int len)
{
	dst->len = len;
	dst->data = (len ? kmemdup(src, len, GFP_KERNEL) : NULL);
	if (len && !dst->data)
		return -ENOMEM;
	return 0;
}

static inline int dup_netobj(struct xdr_netobj *dst, struct xdr_netobj *src)
{
	return dup_to_netobj(dst, src->data, src->len);
}

static void rsi_init(struct cache_head *cnew, struct cache_head *citem)
{
	struct rsi *new = container_of(cnew, struct rsi, h);
	struct rsi *item = container_of(citem, struct rsi, h);

	new->out_handle.data = NULL;
	new->out_handle.len = 0;
	new->out_token.data = NULL;
	new->out_token.len = 0;
	new->in_handle.len = item->in_handle.len;
	item->in_handle.len = 0;
	new->in_token.len = item->in_token.len;
	item->in_token.len = 0;
	new->in_handle.data = item->in_handle.data;
	item->in_handle.data = NULL;
	new->in_token.data = item->in_token.data;
	item->in_token.data = NULL;
}

static void update_rsi(struct cache_head *cnew, struct cache_head *citem)
{
	struct rsi *new = container_of(cnew, struct rsi, h);
	struct rsi *item = container_of(citem, struct rsi, h);

	BUG_ON(new->out_handle.data || new->out_token.data);
	new->out_handle.len = item->out_handle.len;
	item->out_handle.len = 0;
	new->out_token.len = item->out_token.len;
	item->out_token.len = 0;
	new->out_handle.data = item->out_handle.data;
	item->out_handle.data = NULL;
	new->out_token.data = item->out_token.data;
	item->out_token.data = NULL;

	new->major_status = item->major_status;
	new->minor_status = item->minor_status;
}

static struct cache_head *rsi_alloc(void)
{
	struct rsi *rsii = kmalloc(sizeof(*rsii), GFP_KERNEL);
	if (rsii)
		return &rsii->h;
	else
		return NULL;
}

static int rsi_upcall(struct cache_detail *cd, struct cache_head *h)
{
	return sunrpc_cache_pipe_upcall_timeout(cd, h);
}

static void rsi_request(struct cache_detail *cd,
		       struct cache_head *h,
		       char **bpp, int *blen)
{
	struct rsi *rsii = container_of(h, struct rsi, h);

	qword_addhex(bpp, blen, rsii->in_handle.data, rsii->in_handle.len);
	qword_addhex(bpp, blen, rsii->in_token.data, rsii->in_token.len);
	(*bpp)[-1] = '\n';
	WARN_ONCE(*blen < 0,
		  "RPCSEC/GSS credential too large - please use gssproxy\n");
}

static int rsi_parse(struct cache_detail *cd,
		    char *mesg, int mlen)
{
	/* context token expiry major minor context token */
	char *buf = mesg;
	char *ep;
	int len;
	struct rsi rsii, *rsip = NULL;
	time64_t expiry;
	int status = -EINVAL;

	memset(&rsii, 0, sizeof(rsii));
	/* handle */
	len = qword_get(&mesg, buf, mlen);
	if (len < 0)
		goto out;
	status = -ENOMEM;
	if (dup_to_netobj(&rsii.in_handle, buf, len))
		goto out;

	/* token */
	len = qword_get(&mesg, buf, mlen);
	status = -EINVAL;
	if (len < 0)
		goto out;
	status = -ENOMEM;
	if (dup_to_netobj(&rsii.in_token, buf, len))
		goto out;

	rsip = rsi_lookup(cd, &rsii);
	if (!rsip)
		goto out;

	rsii.h.flags = 0;
	/* expiry */
	status = get_expiry(&mesg, &expiry);
	if (status)
		goto out;

	status = -EINVAL;
	/* major/minor */
	len = qword_get(&mesg, buf, mlen);
	if (len <= 0)
		goto out;
	rsii.major_status = simple_strtoul(buf, &ep, 10);
	if (*ep)
		goto out;
	len = qword_get(&mesg, buf, mlen);
	if (len <= 0)
		goto out;
	rsii.minor_status = simple_strtoul(buf, &ep, 10);
	if (*ep)
		goto out;

	/* out_handle */
	len = qword_get(&mesg, buf, mlen);
	if (len < 0)
		goto out;
	status = -ENOMEM;
	if (dup_to_netobj(&rsii.out_handle, buf, len))
		goto out;

	/* out_token */
	len = qword_get(&mesg, buf, mlen);
	status = -EINVAL;
	if (len < 0)
		goto out;
	status = -ENOMEM;
	if (dup_to_netobj(&rsii.out_token, buf, len))
		goto out;
	rsii.h.expiry_time = expiry;
	rsip = rsi_update(cd, &rsii, rsip);
	status = 0;
out:
	rsi_free(&rsii);
	if (rsip)
		cache_put(&rsip->h, cd);
	else
		status = -ENOMEM;
	return status;
}

static const struct cache_detail rsi_cache_template = {
	.owner		= THIS_MODULE,
	.hash_size	= RSI_HASHMAX,
	.name           = "auth.rpcsec.init",
	.cache_put      = rsi_put,
	.cache_upcall	= rsi_upcall,
	.cache_request  = rsi_request,
	.cache_parse    = rsi_parse,
	.match		= rsi_match,
	.init		= rsi_init,
	.update		= update_rsi,
	.alloc		= rsi_alloc,
};

static struct rsi *rsi_lookup(struct cache_detail *cd, struct rsi *item)
{
	struct cache_head *ch;
	int hash = rsi_hash(item);

	ch = sunrpc_cache_lookup_rcu(cd, &item->h, hash);
	if (ch)
		return container_of(ch, struct rsi, h);
	else
		return NULL;
}

static struct rsi *rsi_update(struct cache_detail *cd, struct rsi *new, struct rsi *old)
{
	struct cache_head *ch;
	int hash = rsi_hash(new);

	ch = sunrpc_cache_update(cd, &new->h,
				 &old->h, hash);
	if (ch)
		return container_of(ch, struct rsi, h);
	else
		return NULL;
}


/*
 * The rpcsec_context cache is used to store a context that is
 * used in data exchange.
 * The key is a context handle. The content is:
 *  uid, gidlist, mechanism, service-set, mech-specific-data
 */

#define	RSC_HASHBITS	10
#define	RSC_HASHMAX	(1<<RSC_HASHBITS)

#define GSS_SEQ_WIN	128

struct gss_svc_seq_data {
	/* highest seq number seen so far: */
	u32			sd_max;
	/* for i such that sd_max-GSS_SEQ_WIN < i <= sd_max, the i-th bit of
	 * sd_win is nonzero iff sequence number i has been seen already: */
	unsigned long		sd_win[GSS_SEQ_WIN/BITS_PER_LONG];
	spinlock_t		sd_lock;
};

struct rsc {
	struct cache_head	h;
	struct xdr_netobj	handle;
	struct svc_cred		cred;
	struct gss_svc_seq_data	seqdata;
	struct gss_ctx		*mechctx;
	struct rcu_head		rcu_head;
};

static struct rsc *rsc_update(struct cache_detail *cd, struct rsc *new, struct rsc *old);
static struct rsc *rsc_lookup(struct cache_detail *cd, struct rsc *item);

static void rsc_free(struct rsc *rsci)
{
	kfree(rsci->handle.data);
	if (rsci->mechctx)
		gss_delete_sec_context(&rsci->mechctx);
	free_svc_cred(&rsci->cred);
}

static void rsc_free_rcu(struct rcu_head *head)
{
	struct rsc *rsci = container_of(head, struct rsc, rcu_head);

	kfree(rsci->handle.data);
	kfree(rsci);
}

static void rsc_put(struct kref *ref)
{
	struct rsc *rsci = container_of(ref, struct rsc, h.ref);

	if (rsci->mechctx)
		gss_delete_sec_context(&rsci->mechctx);
	free_svc_cred(&rsci->cred);
	call_rcu(&rsci->rcu_head, rsc_free_rcu);
}

static inline int
rsc_hash(struct rsc *rsci)
{
	return hash_mem(rsci->handle.data, rsci->handle.len, RSC_HASHBITS);
}

static int
rsc_match(struct cache_head *a, struct cache_head *b)
{
	struct rsc *new = container_of(a, struct rsc, h);
	struct rsc *tmp = container_of(b, struct rsc, h);

	return netobj_equal(&new->handle, &tmp->handle);
}

static void
rsc_init(struct cache_head *cnew, struct cache_head *ctmp)
{
	struct rsc *new = container_of(cnew, struct rsc, h);
	struct rsc *tmp = container_of(ctmp, struct rsc, h);

	new->handle.len = tmp->handle.len;
	tmp->handle.len = 0;
	new->handle.data = tmp->handle.data;
	tmp->handle.data = NULL;
	new->mechctx = NULL;
	init_svc_cred(&new->cred);
}

static void
update_rsc(struct cache_head *cnew, struct cache_head *ctmp)
{
	struct rsc *new = container_of(cnew, struct rsc, h);
	struct rsc *tmp = container_of(ctmp, struct rsc, h);

	new->mechctx = tmp->mechctx;
	tmp->mechctx = NULL;
	memset(&new->seqdata, 0, sizeof(new->seqdata));
	spin_lock_init(&new->seqdata.sd_lock);
	new->cred = tmp->cred;
	init_svc_cred(&tmp->cred);
}

static struct cache_head *
rsc_alloc(void)
{
	struct rsc *rsci = kmalloc(sizeof(*rsci), GFP_KERNEL);
	if (rsci)
		return &rsci->h;
	else
		return NULL;
}

static int rsc_upcall(struct cache_detail *cd, struct cache_head *h)
{
	return -EINVAL;
}

static int rsc_parse(struct cache_detail *cd,
		     char *mesg, int mlen)
{
	/* contexthandle expiry [ uid gid N <n gids> mechname ...mechdata... ] */
	char *buf = mesg;
	int id;
	int len, rv;
	struct rsc rsci, *rscp = NULL;
	time64_t expiry;
	int status = -EINVAL;
	struct gss_api_mech *gm = NULL;

	memset(&rsci, 0, sizeof(rsci));
	/* context handle */
	len = qword_get(&mesg, buf, mlen);
	if (len < 0) goto out;
	status = -ENOMEM;
	if (dup_to_netobj(&rsci.handle, buf, len))
		goto out;

	rsci.h.flags = 0;
	/* expiry */
	status = get_expiry(&mesg, &expiry);
	if (status)
		goto out;

	status = -EINVAL;
	rscp = rsc_lookup(cd, &rsci);
	if (!rscp)
		goto out;

	/* uid, or NEGATIVE */
	rv = get_int(&mesg, &id);
	if (rv == -EINVAL)
		goto out;
	if (rv == -ENOENT)
		set_bit(CACHE_NEGATIVE, &rsci.h.flags);
	else {
		int N, i;

		/*
		 * NOTE: we skip uid_valid()/gid_valid() checks here:
		 * instead, * -1 id's are later mapped to the
		 * (export-specific) anonymous id by nfsd_setuser.
		 *
		 * (But supplementary gid's get no such special
		 * treatment so are checked for validity here.)
		 */
		/* uid */
		rsci.cred.cr_uid = make_kuid(current_user_ns(), id);

		/* gid */
		if (get_int(&mesg, &id))
			goto out;
		rsci.cred.cr_gid = make_kgid(current_user_ns(), id);

		/* number of additional gid's */
		if (get_int(&mesg, &N))
			goto out;
		if (N < 0 || N > NGROUPS_MAX)
			goto out;
		status = -ENOMEM;
		rsci.cred.cr_group_info = groups_alloc(N);
		if (rsci.cred.cr_group_info == NULL)
			goto out;

		/* gid's */
		status = -EINVAL;
		for (i=0; i<N; i++) {
			kgid_t kgid;
			if (get_int(&mesg, &id))
				goto out;
			kgid = make_kgid(current_user_ns(), id);
			if (!gid_valid(kgid))
				goto out;
			rsci.cred.cr_group_info->gid[i] = kgid;
		}
		groups_sort(rsci.cred.cr_group_info);

		/* mech name */
		len = qword_get(&mesg, buf, mlen);
		if (len < 0)
			goto out;
		gm = rsci.cred.cr_gss_mech = gss_mech_get_by_name(buf);
		status = -EOPNOTSUPP;
		if (!gm)
			goto out;

		status = -EINVAL;
		/* mech-specific data: */
		len = qword_get(&mesg, buf, mlen);
		if (len < 0)
			goto out;
		status = gss_import_sec_context(buf, len, gm, &rsci.mechctx,
						NULL, GFP_KERNEL);
		if (status)
			goto out;

		/* get client name */
		len = qword_get(&mesg, buf, mlen);
		if (len > 0) {
			rsci.cred.cr_principal = kstrdup(buf, GFP_KERNEL);
			if (!rsci.cred.cr_principal) {
				status = -ENOMEM;
				goto out;
			}
		}

	}
	rsci.h.expiry_time = expiry;
	rscp = rsc_update(cd, &rsci, rscp);
	status = 0;
out:
	rsc_free(&rsci);
	if (rscp)
		cache_put(&rscp->h, cd);
	else
		status = -ENOMEM;
	return status;
}

static const struct cache_detail rsc_cache_template = {
	.owner		= THIS_MODULE,
	.hash_size	= RSC_HASHMAX,
	.name		= "auth.rpcsec.context",
	.cache_put	= rsc_put,
	.cache_upcall	= rsc_upcall,
	.cache_parse	= rsc_parse,
	.match		= rsc_match,
	.init		= rsc_init,
	.update		= update_rsc,
	.alloc		= rsc_alloc,
};

static struct rsc *rsc_lookup(struct cache_detail *cd, struct rsc *item)
{
	struct cache_head *ch;
	int hash = rsc_hash(item);

	ch = sunrpc_cache_lookup_rcu(cd, &item->h, hash);
	if (ch)
		return container_of(ch, struct rsc, h);
	else
		return NULL;
}

static struct rsc *rsc_update(struct cache_detail *cd, struct rsc *new, struct rsc *old)
{
	struct cache_head *ch;
	int hash = rsc_hash(new);

	ch = sunrpc_cache_update(cd, &new->h,
				 &old->h, hash);
	if (ch)
		return container_of(ch, struct rsc, h);
	else
		return NULL;
}


static struct rsc *
gss_svc_searchbyctx(struct cache_detail *cd, struct xdr_netobj *handle)
{
	struct rsc rsci;
	struct rsc *found;

	memset(&rsci, 0, sizeof(rsci));
	if (dup_to_netobj(&rsci.handle, handle->data, handle->len))
		return NULL;
	found = rsc_lookup(cd, &rsci);
	rsc_free(&rsci);
	if (!found)
		return NULL;
	if (cache_check(cd, &found->h, NULL))
		return NULL;
	return found;
}

/**
 * gss_check_seq_num - GSS sequence number window check
 * @rqstp: RPC Call to use when reporting errors
 * @rsci: cached GSS context state (updated on return)
 * @seq_num: sequence number to check
 *
 * Implements sequence number algorithm as specified in
 * RFC 2203, Section 5.3.3.1. "Context Management".
 *
 * Return values:
 *   %true: @rqstp's GSS sequence number is inside the window
 *   %false: @rqstp's GSS sequence number is outside the window
 */
static bool gss_check_seq_num(const struct svc_rqst *rqstp, struct rsc *rsci,
			      u32 seq_num)
{
	struct gss_svc_seq_data *sd = &rsci->seqdata;
	bool result = false;

	spin_lock(&sd->sd_lock);
	if (seq_num > sd->sd_max) {
		if (seq_num >= sd->sd_max + GSS_SEQ_WIN) {
			memset(sd->sd_win, 0, sizeof(sd->sd_win));
			sd->sd_max = seq_num;
		} else while (sd->sd_max < seq_num) {
			sd->sd_max++;
			__clear_bit(sd->sd_max % GSS_SEQ_WIN, sd->sd_win);
		}
		__set_bit(seq_num % GSS_SEQ_WIN, sd->sd_win);
		goto ok;
	} else if (seq_num + GSS_SEQ_WIN <= sd->sd_max) {
		goto toolow;
	}
	if (__test_and_set_bit(seq_num % GSS_SEQ_WIN, sd->sd_win))
		goto alreadyseen;

ok:
	result = true;
out:
	spin_unlock(&sd->sd_lock);
	return result;

toolow:
	trace_rpcgss_svc_seqno_low(rqstp, seq_num,
				   sd->sd_max - GSS_SEQ_WIN,
				   sd->sd_max);
	goto out;
alreadyseen:
	trace_rpcgss_svc_seqno_seen(rqstp, seq_num);
	goto out;
}

/*
 * Decode and verify a Call's verifier field. For RPC_AUTH_GSS Calls,
 * the body of this field contains a variable length checksum.
 *
 * GSS-specific auth_stat values are mandated by RFC 2203 Section
 * 5.3.3.3.
 */
static int
svcauth_gss_verify_header(struct svc_rqst *rqstp, struct rsc *rsci,
			  __be32 *rpcstart, struct rpc_gss_wire_cred *gc)
{
	struct xdr_stream	*xdr = &rqstp->rq_arg_stream;
	struct gss_ctx		*ctx_id = rsci->mechctx;
	u32			flavor, maj_stat;
	struct xdr_buf		rpchdr;
	struct xdr_netobj	checksum;
	struct kvec		iov;

	/*
	 * Compute the checksum of the incoming Call from the
	 * XID field to credential field:
	 */
	iov.iov_base = rpcstart;
	iov.iov_len = (u8 *)xdr->p - (u8 *)rpcstart;
	xdr_buf_from_iov(&iov, &rpchdr);

	/* Call's verf field: */
	if (xdr_stream_decode_opaque_auth(xdr, &flavor,
					  (void **)&checksum.data,
					  &checksum.len) < 0) {
		rqstp->rq_auth_stat = rpc_autherr_badverf;
		return SVC_DENIED;
	}
	if (flavor != RPC_AUTH_GSS) {
		rqstp->rq_auth_stat = rpc_autherr_badverf;
		return SVC_DENIED;
	}

	if (rqstp->rq_deferred)
		return SVC_OK;
	maj_stat = gss_verify_mic(ctx_id, &rpchdr, &checksum);
	if (maj_stat != GSS_S_COMPLETE) {
		trace_rpcgss_svc_mic(rqstp, maj_stat);
		rqstp->rq_auth_stat = rpcsec_gsserr_credproblem;
		return SVC_DENIED;
	}

	if (gc->gc_seq > MAXSEQ) {
		trace_rpcgss_svc_seqno_large(rqstp, gc->gc_seq);
		rqstp->rq_auth_stat = rpcsec_gsserr_ctxproblem;
		return SVC_DENIED;
	}
	if (!gss_check_seq_num(rqstp, rsci, gc->gc_seq))
		return SVC_DROP;
	return SVC_OK;
}

/*
 * Construct and encode a Reply's verifier field. The verifier's body
 * field contains a variable-length checksum of the GSS sequence
 * number.
 */
static bool
svcauth_gss_encode_verf(struct svc_rqst *rqstp, struct gss_ctx *ctx_id, u32 seq)
{
	struct gss_svc_data	*gsd = rqstp->rq_auth_data;
	u32			maj_stat;
	struct xdr_buf		verf_data;
	struct xdr_netobj	checksum;
	struct kvec		iov;

	gsd->gsd_seq_num = cpu_to_be32(seq);
	iov.iov_base = &gsd->gsd_seq_num;
	iov.iov_len = XDR_UNIT;
	xdr_buf_from_iov(&iov, &verf_data);

	checksum.data = gsd->gsd_scratch;
	maj_stat = gss_get_mic(ctx_id, &verf_data, &checksum);
	if (maj_stat != GSS_S_COMPLETE)
		goto bad_mic;

	return xdr_stream_encode_opaque_auth(&rqstp->rq_res_stream, RPC_AUTH_GSS,
					     checksum.data, checksum.len) > 0;

bad_mic:
	trace_rpcgss_svc_get_mic(rqstp, maj_stat);
	return false;
}

struct gss_domain {
	struct auth_domain	h;
	u32			pseudoflavor;
};

static struct auth_domain *
find_gss_auth_domain(struct gss_ctx *ctx, u32 svc)
{
	char *name;

	name = gss_service_to_auth_domain_name(ctx->mech_type, svc);
	if (!name)
		return NULL;
	return auth_domain_find(name);
}

static struct auth_ops svcauthops_gss;

u32 svcauth_gss_flavor(struct auth_domain *dom)
{
	struct gss_domain *gd = container_of(dom, struct gss_domain, h);

	return gd->pseudoflavor;
}

EXPORT_SYMBOL_GPL(svcauth_gss_flavor);

struct auth_domain *
svcauth_gss_register_pseudoflavor(u32 pseudoflavor, char * name)
{
	struct gss_domain	*new;
	struct auth_domain	*test;
	int			stat = -ENOMEM;

	new = kmalloc(sizeof(*new), GFP_KERNEL);
	if (!new)
		goto out;
	kref_init(&new->h.ref);
	new->h.name = kstrdup(name, GFP_KERNEL);
	if (!new->h.name)
		goto out_free_dom;
	new->h.flavour = &svcauthops_gss;
	new->pseudoflavor = pseudoflavor;

	test = auth_domain_lookup(name, &new->h);
	if (test != &new->h) {
		pr_warn("svc: duplicate registration of gss pseudo flavour %s.\n",
			name);
		stat = -EADDRINUSE;
		auth_domain_put(test);
		goto out_free_name;
	}
	return test;

out_free_name:
	kfree(new->h.name);
out_free_dom:
	kfree(new);
out:
	return ERR_PTR(stat);
}
EXPORT_SYMBOL_GPL(svcauth_gss_register_pseudoflavor);

/*
 * RFC 2203, Section 5.3.2.2
 *
 *	struct rpc_gss_integ_data {
 *		opaque databody_integ<>;
 *		opaque checksum<>;
 *	};
 *
 *	struct rpc_gss_data_t {
 *		unsigned int seq_num;
 *		proc_req_arg_t arg;
 *	};
 */
static noinline_for_stack int
svcauth_gss_unwrap_integ(struct svc_rqst *rqstp, u32 seq, struct gss_ctx *ctx)
{
	struct gss_svc_data *gsd = rqstp->rq_auth_data;
	struct xdr_stream *xdr = &rqstp->rq_arg_stream;
	u32 len, offset, seq_num, maj_stat;
	struct xdr_buf *buf = xdr->buf;
	struct xdr_buf databody_integ;
	struct xdr_netobj checksum;

	/* Did we already verify the signature on the original pass through? */
	if (rqstp->rq_deferred)
		return 0;

	if (xdr_stream_decode_u32(xdr, &len) < 0)
		goto unwrap_failed;
	if (len & 3)
		goto unwrap_failed;
	offset = xdr_stream_pos(xdr);
	if (xdr_buf_subsegment(buf, &databody_integ, offset, len))
		goto unwrap_failed;

	/*
	 * The xdr_stream now points to the @seq_num field. The next
	 * XDR data item is the @arg field, which contains the clear
	 * text RPC program payload. The checksum, which follows the
	 * @arg field, is located and decoded without updating the
	 * xdr_stream.
	 */

	offset += len;
	if (xdr_decode_word(buf, offset, &checksum.len))
		goto unwrap_failed;
	if (checksum.len > sizeof(gsd->gsd_scratch))
		goto unwrap_failed;
	checksum.data = gsd->gsd_scratch;
	if (read_bytes_from_xdr_buf(buf, offset + XDR_UNIT, checksum.data,
				    checksum.len))
		goto unwrap_failed;

	maj_stat = gss_verify_mic(ctx, &databody_integ, &checksum);
	if (maj_stat != GSS_S_COMPLETE)
		goto bad_mic;

	/* The received seqno is protected by the checksum. */
	if (xdr_stream_decode_u32(xdr, &seq_num) < 0)
		goto unwrap_failed;
	if (seq_num != seq)
		goto bad_seqno;

	xdr_truncate_decode(xdr, XDR_UNIT + checksum.len);
	return 0;

unwrap_failed:
	trace_rpcgss_svc_unwrap_failed(rqstp);
	return -EINVAL;
bad_seqno:
	trace_rpcgss_svc_seqno_bad(rqstp, seq, seq_num);
	return -EINVAL;
bad_mic:
	trace_rpcgss_svc_mic(rqstp, maj_stat);
	return -EINVAL;
}

/*
 * RFC 2203, Section 5.3.2.3
 *
 *	struct rpc_gss_priv_data {
 *		opaque databody_priv<>
 *	};
 *
 *	struct rpc_gss_data_t {
 *		unsigned int seq_num;
 *		proc_req_arg_t arg;
 *	};
 */
static noinline_for_stack int
svcauth_gss_unwrap_priv(struct svc_rqst *rqstp, u32 seq, struct gss_ctx *ctx)
{
	struct xdr_stream *xdr = &rqstp->rq_arg_stream;
	u32 len, maj_stat, seq_num, offset;
	struct xdr_buf *buf = xdr->buf;
	unsigned int saved_len;

	if (xdr_stream_decode_u32(xdr, &len) < 0)
		goto unwrap_failed;
	if (rqstp->rq_deferred) {
		/* Already decrypted last time through! The sequence number
		 * check at out_seq is unnecessary but harmless: */
		goto out_seq;
	}
	if (len > xdr_stream_remaining(xdr))
		goto unwrap_failed;
	offset = xdr_stream_pos(xdr);

	saved_len = buf->len;
	maj_stat = gss_unwrap(ctx, offset, offset + len, buf);
	if (maj_stat != GSS_S_COMPLETE)
		goto bad_unwrap;
	xdr->nwords -= XDR_QUADLEN(saved_len - buf->len);

out_seq:
	/* gss_unwrap() decrypted the sequence number. */
	if (xdr_stream_decode_u32(xdr, &seq_num) < 0)
		goto unwrap_failed;
	if (seq_num != seq)
		goto bad_seqno;
	return 0;

unwrap_failed:
	trace_rpcgss_svc_unwrap_failed(rqstp);
	return -EINVAL;
bad_seqno:
	trace_rpcgss_svc_seqno_bad(rqstp, seq, seq_num);
	return -EINVAL;
bad_unwrap:
	trace_rpcgss_svc_unwrap(rqstp, maj_stat);
	return -EINVAL;
}

static enum svc_auth_status
svcauth_gss_set_client(struct svc_rqst *rqstp)
{
	struct gss_svc_data *svcdata = rqstp->rq_auth_data;
	struct rsc *rsci = svcdata->rsci;
	struct rpc_gss_wire_cred *gc = &svcdata->clcred;
	int stat;

	rqstp->rq_auth_stat = rpc_autherr_badcred;

	/*
	 * A gss export can be specified either by:
	 * 	export	*(sec=krb5,rw)
	 * or by
	 * 	export gss/krb5(rw)
	 * The latter is deprecated; but for backwards compatibility reasons
	 * the nfsd code will still fall back on trying it if the former
	 * doesn't work; so we try to make both available to nfsd, below.
	 */
	rqstp->rq_gssclient = find_gss_auth_domain(rsci->mechctx, gc->gc_svc);
	if (rqstp->rq_gssclient == NULL)
		return SVC_DENIED;
	stat = svcauth_unix_set_client(rqstp);
	if (stat == SVC_DROP || stat == SVC_CLOSE)
		return stat;

	rqstp->rq_auth_stat = rpc_auth_ok;
	return SVC_OK;
}

static bool
svcauth_gss_proc_init_verf(struct cache_detail *cd, struct svc_rqst *rqstp,
			   struct xdr_netobj *out_handle, int *major_status,
			   u32 seq_num)
{
	struct xdr_stream *xdr = &rqstp->rq_res_stream;
	struct rsc *rsci;
	bool rc;

	if (*major_status != GSS_S_COMPLETE)
		goto null_verifier;
	rsci = gss_svc_searchbyctx(cd, out_handle);
	if (rsci == NULL) {
		*major_status = GSS_S_NO_CONTEXT;
		goto null_verifier;
	}

	rc = svcauth_gss_encode_verf(rqstp, rsci->mechctx, seq_num);
	cache_put(&rsci->h, cd);
	return rc;

null_verifier:
	return xdr_stream_encode_opaque_auth(xdr, RPC_AUTH_NULL, NULL, 0) > 0;
}

static void gss_free_in_token_pages(struct gssp_in_token *in_token)
{
	int i;

	i = 0;
	while (in_token->pages[i])
		put_page(in_token->pages[i++]);
	kfree(in_token->pages);
	in_token->pages = NULL;
}

static int gss_read_proxy_verf(struct svc_rqst *rqstp,
			       struct rpc_gss_wire_cred *gc,
			       struct xdr_netobj *in_handle,
			       struct gssp_in_token *in_token)
{
	struct xdr_stream *xdr = &rqstp->rq_arg_stream;
	unsigned int length, pgto_offs, pgfrom_offs;
	int pages, i, pgto, pgfrom;
	size_t to_offs, from_offs;
	u32 inlen;

	if (dup_netobj(in_handle, &gc->gc_ctx))
		return SVC_CLOSE;

	/*
	 *  RFC 2203 Section 5.2.2
	 *
	 *	struct rpc_gss_init_arg {
	 *		opaque gss_token<>;
	 *	};
	 */
	if (xdr_stream_decode_u32(xdr, &inlen) < 0)
		goto out_denied_free;
	if (inlen > xdr_stream_remaining(xdr))
		goto out_denied_free;

	pages = DIV_ROUND_UP(inlen, PAGE_SIZE);
	in_token->pages = kcalloc(pages + 1, sizeof(struct page *), GFP_KERNEL);
	if (!in_token->pages)
		goto out_denied_free;
	in_token->page_base = 0;
	in_token->page_len = inlen;
	for (i = 0; i < pages; i++) {
		in_token->pages[i] = alloc_page(GFP_KERNEL);
		if (!in_token->pages[i]) {
			gss_free_in_token_pages(in_token);
			goto out_denied_free;
		}
	}

	length = min_t(unsigned int, inlen, (char *)xdr->end - (char *)xdr->p);
	memcpy(page_address(in_token->pages[0]), xdr->p, length);
	inlen -= length;

	to_offs = length;
	from_offs = rqstp->rq_arg.page_base;
	while (inlen) {
		pgto = to_offs >> PAGE_SHIFT;
		pgfrom = from_offs >> PAGE_SHIFT;
		pgto_offs = to_offs & ~PAGE_MASK;
		pgfrom_offs = from_offs & ~PAGE_MASK;

		length = min_t(unsigned int, inlen,
			 min_t(unsigned int, PAGE_SIZE - pgto_offs,
			       PAGE_SIZE - pgfrom_offs));
		memcpy(page_address(in_token->pages[pgto]) + pgto_offs,
		       page_address(rqstp->rq_arg.pages[pgfrom]) + pgfrom_offs,
		       length);

		to_offs += length;
		from_offs += length;
		inlen -= length;
	}
	return 0;

out_denied_free:
	kfree(in_handle->data);
	return SVC_DENIED;
}

/*
 * RFC 2203, Section 5.2.3.1.
 *
 *	struct rpc_gss_init_res {
 *		opaque handle<>;
 *		unsigned int gss_major;
 *		unsigned int gss_minor;
 *		unsigned int seq_window;
 *		opaque gss_token<>;
 *	};
 */
static bool
svcxdr_encode_gss_init_res(struct xdr_stream *xdr,
			   struct xdr_netobj *handle,
			   struct xdr_netobj *gss_token,
			   unsigned int major_status,
			   unsigned int minor_status, u32 seq_num)
{
	if (xdr_stream_encode_opaque(xdr, handle->data, handle->len) < 0)
		return false;
	if (xdr_stream_encode_u32(xdr, major_status) < 0)
		return false;
	if (xdr_stream_encode_u32(xdr, minor_status) < 0)
		return false;
	if (xdr_stream_encode_u32(xdr, seq_num) < 0)
		return false;
	if (xdr_stream_encode_opaque(xdr, gss_token->data, gss_token->len) < 0)
		return false;
	return true;
}

/*
 * Having read the cred already and found we're in the context
 * initiation case, read the verifier and initiate (or check the results
 * of) upcalls to userspace for help with context initiation.  If
 * the upcall results are available, write the verifier and result.
 * Otherwise, drop the request pending an answer to the upcall.
 */
static int
svcauth_gss_legacy_init(struct svc_rqst *rqstp,
			struct rpc_gss_wire_cred *gc)
{
	struct xdr_stream *xdr = &rqstp->rq_arg_stream;
	struct rsi *rsip, rsikey;
	__be32 *p;
	u32 len;
	int ret;
	struct sunrpc_net *sn = net_generic(SVC_NET(rqstp), sunrpc_net_id);

	memset(&rsikey, 0, sizeof(rsikey));
	if (dup_netobj(&rsikey.in_handle, &gc->gc_ctx))
		return SVC_CLOSE;

	/*
	 *  RFC 2203 Section 5.2.2
	 *
	 *	struct rpc_gss_init_arg {
	 *		opaque gss_token<>;
	 *	};
	 */
	if (xdr_stream_decode_u32(xdr, &len) < 0) {
		kfree(rsikey.in_handle.data);
		return SVC_DENIED;
	}
	p = xdr_inline_decode(xdr, len);
	if (!p) {
		kfree(rsikey.in_handle.data);
		return SVC_DENIED;
	}
	rsikey.in_token.data = kmalloc(len, GFP_KERNEL);
	if (ZERO_OR_NULL_PTR(rsikey.in_token.data)) {
		kfree(rsikey.in_handle.data);
		return SVC_CLOSE;
	}
	memcpy(rsikey.in_token.data, p, len);
	rsikey.in_token.len = len;

	/* Perform upcall, or find upcall result: */
	rsip = rsi_lookup(sn->rsi_cache, &rsikey);
	rsi_free(&rsikey);
	if (!rsip)
		return SVC_CLOSE;
	if (cache_check(sn->rsi_cache, &rsip->h, &rqstp->rq_chandle) < 0)
		/* No upcall result: */
		return SVC_CLOSE;

	ret = SVC_CLOSE;
	if (!svcauth_gss_proc_init_verf(sn->rsc_cache, rqstp, &rsip->out_handle,
					&rsip->major_status, GSS_SEQ_WIN))
		goto out;
	if (!svcxdr_set_accept_stat(rqstp))
		goto out;
	if (!svcxdr_encode_gss_init_res(&rqstp->rq_res_stream, &rsip->out_handle,
					&rsip->out_token, rsip->major_status,
					rsip->minor_status, GSS_SEQ_WIN))
		goto out;

	ret = SVC_COMPLETE;
out:
	cache_put(&rsip->h, sn->rsi_cache);
	return ret;
}

static int gss_proxy_save_rsc(struct cache_detail *cd,
				struct gssp_upcall_data *ud,
				uint64_t *handle)
{
	struct rsc rsci, *rscp = NULL;
	static atomic64_t ctxhctr;
	long long ctxh;
	struct gss_api_mech *gm = NULL;
	time64_t expiry;
	int status;

	memset(&rsci, 0, sizeof(rsci));
	/* context handle */
	status = -ENOMEM;
	/* the handle needs to be just a unique id,
	 * use a static counter */
	ctxh = atomic64_inc_return(&ctxhctr);

	/* make a copy for the caller */
	*handle = ctxh;

	/* make a copy for the rsc cache */
	if (dup_to_netobj(&rsci.handle, (char *)handle, sizeof(uint64_t)))
		goto out;
	rscp = rsc_lookup(cd, &rsci);
	if (!rscp)
		goto out;

	/* creds */
	if (!ud->found_creds) {
		/* userspace seem buggy, we should always get at least a
		 * mapping to nobody */
		goto out;
	} else {
		struct timespec64 boot;

		/* steal creds */
		rsci.cred = ud->creds;
		memset(&ud->creds, 0, sizeof(struct svc_cred));

		status = -EOPNOTSUPP;
		/* get mech handle from OID */
		gm = gss_mech_get_by_OID(&ud->mech_oid);
		if (!gm)
			goto out;
		rsci.cred.cr_gss_mech = gm;

		status = -EINVAL;
		/* mech-specific data: */
		status = gss_import_sec_context(ud->out_handle.data,
						ud->out_handle.len,
						gm, &rsci.mechctx,
						&expiry, GFP_KERNEL);
		if (status)
			goto out;

		getboottime64(&boot);
		expiry -= boot.tv_sec;
	}

	rsci.h.expiry_time = expiry;
	rscp = rsc_update(cd, &rsci, rscp);
	status = 0;
out:
	rsc_free(&rsci);
	if (rscp)
		cache_put(&rscp->h, cd);
	else
		status = -ENOMEM;
	return status;
}

static int svcauth_gss_proxy_init(struct svc_rqst *rqstp,
				  struct rpc_gss_wire_cred *gc)
{
	struct xdr_netobj cli_handle;
	struct gssp_upcall_data ud;
	uint64_t handle;
	int status;
	int ret;
	struct net *net = SVC_NET(rqstp);
	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);

	memset(&ud, 0, sizeof(ud));
	ret = gss_read_proxy_verf(rqstp, gc, &ud.in_handle, &ud.in_token);
	if (ret)
		return ret;

	ret = SVC_CLOSE;

	/* Perform synchronous upcall to gss-proxy */
	status = gssp_accept_sec_context_upcall(net, &ud);
	if (status)
		goto out;

	trace_rpcgss_svc_accept_upcall(rqstp, ud.major_status, ud.minor_status);

	switch (ud.major_status) {
	case GSS_S_CONTINUE_NEEDED:
		cli_handle = ud.out_handle;
		break;
	case GSS_S_COMPLETE:
		status = gss_proxy_save_rsc(sn->rsc_cache, &ud, &handle);
		if (status)
			goto out;
		cli_handle.data = (u8 *)&handle;
		cli_handle.len = sizeof(handle);
		break;
	default:
		goto out;
	}

	if (!svcauth_gss_proc_init_verf(sn->rsc_cache, rqstp, &cli_handle,
					&ud.major_status, GSS_SEQ_WIN))
		goto out;
	if (!svcxdr_set_accept_stat(rqstp))
		goto out;
	if (!svcxdr_encode_gss_init_res(&rqstp->rq_res_stream, &cli_handle,
					&ud.out_token, ud.major_status,
					ud.minor_status, GSS_SEQ_WIN))
		goto out;

	ret = SVC_COMPLETE;
out:
	gss_free_in_token_pages(&ud.in_token);
	gssp_free_upcall_data(&ud);
	return ret;
}

/*
 * Try to set the sn->use_gss_proxy variable to a new value. We only allow
 * it to be changed if it's currently undefined (-1). If it's any other value
 * then return -EBUSY unless the type wouldn't have changed anyway.
 */
static int set_gss_proxy(struct net *net, int type)
{
	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
	int ret;

	WARN_ON_ONCE(type != 0 && type != 1);
	ret = cmpxchg(&sn->use_gss_proxy, -1, type);
	if (ret != -1 && ret != type)
		return -EBUSY;
	return 0;
}

static bool use_gss_proxy(struct net *net)
{
	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);

	/* If use_gss_proxy is still undefined, then try to disable it */
	if (sn->use_gss_proxy == -1)
		set_gss_proxy(net, 0);
	return sn->use_gss_proxy;
}

static noinline_for_stack int
svcauth_gss_proc_init(struct svc_rqst *rqstp, struct rpc_gss_wire_cred *gc)
{
	struct xdr_stream *xdr = &rqstp->rq_arg_stream;
	u32 flavor, len;
	void *body;

	/* Call's verf field: */
	if (xdr_stream_decode_opaque_auth(xdr, &flavor, &body, &len) < 0)
		return SVC_GARBAGE;
	if (flavor != RPC_AUTH_NULL || len != 0) {
		rqstp->rq_auth_stat = rpc_autherr_badverf;
		return SVC_DENIED;
	}

	if (gc->gc_proc == RPC_GSS_PROC_INIT && gc->gc_ctx.len != 0) {
		rqstp->rq_auth_stat = rpc_autherr_badcred;
		return SVC_DENIED;
	}

	if (!use_gss_proxy(SVC_NET(rqstp)))
		return svcauth_gss_legacy_init(rqstp, gc);
	return svcauth_gss_proxy_init(rqstp, gc);
}

#ifdef CONFIG_PROC_FS

static ssize_t write_gssp(struct file *file, const char __user *buf,
			 size_t count, loff_t *ppos)
{
	struct net *net = pde_data(file_inode(file));
	char tbuf[20];
	unsigned long i;
	int res;

	if (*ppos || count > sizeof(tbuf)-1)
		return -EINVAL;
	if (copy_from_user(tbuf, buf, count))
		return -EFAULT;

	tbuf[count] = 0;
	res = kstrtoul(tbuf, 0, &i);
	if (res)
		return res;
	if (i != 1)
		return -EINVAL;
	res = set_gssp_clnt(net);
	if (res)
		return res;
	res = set_gss_proxy(net, 1);
	if (res)
		return res;
	return count;
}

static ssize_t read_gssp(struct file *file, char __user *buf,
			 size_t count, loff_t *ppos)
{
	struct net *net = pde_data(file_inode(file));
	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
	unsigned long p = *ppos;
	char tbuf[10];
	size_t len;

	snprintf(tbuf, sizeof(tbuf), "%d\n", sn->use_gss_proxy);
	len = strlen(tbuf);
	if (p >= len)
		return 0;
	len -= p;
	if (len > count)
		len = count;
	if (copy_to_user(buf, (void *)(tbuf+p), len))
		return -EFAULT;
	*ppos += len;
	return len;
}

static const struct proc_ops use_gss_proxy_proc_ops = {
	.proc_open	= nonseekable_open,
	.proc_write	= write_gssp,
	.proc_read	= read_gssp,
};

static int create_use_gss_proxy_proc_entry(struct net *net)
{
	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
	struct proc_dir_entry **p = &sn->use_gssp_proc;

	sn->use_gss_proxy = -1;
	*p = proc_create_data("use-gss-proxy", S_IFREG | 0600,
			      sn->proc_net_rpc,
			      &use_gss_proxy_proc_ops, net);
	if (!*p)
		return -ENOMEM;
	init_gssp_clnt(sn);
	return 0;
}

static void destroy_use_gss_proxy_proc_entry(struct net *net)
{
	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);

	if (sn->use_gssp_proc) {
		remove_proc_entry("use-gss-proxy", sn->proc_net_rpc);
		clear_gssp_clnt(sn);
	}
}

static ssize_t read_gss_krb5_enctypes(struct file *file, char __user *buf,
				      size_t count, loff_t *ppos)
{
	struct rpcsec_gss_oid oid = {
		.len	= 9,
		.data	= "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02",
	};
	struct gss_api_mech *mech;
	ssize_t ret;

	mech = gss_mech_get_by_OID(&oid);
	if (!mech)
		return 0;
	if (!mech->gm_upcall_enctypes) {
		gss_mech_put(mech);
		return 0;
	}

	ret = simple_read_from_buffer(buf, count, ppos,
				      mech->gm_upcall_enctypes,
				      strlen(mech->gm_upcall_enctypes));
	gss_mech_put(mech);
	return ret;
}

static const struct proc_ops gss_krb5_enctypes_proc_ops = {
	.proc_open	= nonseekable_open,
	.proc_read	= read_gss_krb5_enctypes,
};

static int create_krb5_enctypes_proc_entry(struct net *net)
{
	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);

	sn->gss_krb5_enctypes =
		proc_create_data("gss_krb5_enctypes", S_IFREG | 0444,
				 sn->proc_net_rpc, &gss_krb5_enctypes_proc_ops,
				 net);
	return sn->gss_krb5_enctypes ? 0 : -ENOMEM;
}

static void destroy_krb5_enctypes_proc_entry(struct net *net)
{
	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);

	if (sn->gss_krb5_enctypes)
		remove_proc_entry("gss_krb5_enctypes", sn->proc_net_rpc);
}

#else /* CONFIG_PROC_FS */

static int create_use_gss_proxy_proc_entry(struct net *net)
{
	return 0;
}

static void destroy_use_gss_proxy_proc_entry(struct net *net) {}

static int create_krb5_enctypes_proc_entry(struct net *net)
{
	return 0;
}

static void destroy_krb5_enctypes_proc_entry(struct net *net) {}

#endif /* CONFIG_PROC_FS */

/*
 * The Call's credential body should contain a struct rpc_gss_cred_t.
 *
 * RFC 2203 Section 5
 *
 *	struct rpc_gss_cred_t {
 *		union switch (unsigned int version) {
 *		case RPCSEC_GSS_VERS_1:
 *			struct {
 *				rpc_gss_proc_t gss_proc;
 *				unsigned int seq_num;
 *				rpc_gss_service_t service;
 *				opaque handle<>;
 *			} rpc_gss_cred_vers_1_t;
 *		}
 *	};
 */
static bool
svcauth_gss_decode_credbody(struct xdr_stream *xdr,
			    struct rpc_gss_wire_cred *gc,
			    __be32 **rpcstart)
{
	ssize_t handle_len;
	u32 body_len;
	__be32 *p;

	p = xdr_inline_decode(xdr, XDR_UNIT);
	if (!p)
		return false;
	/*
	 * start of rpc packet is 7 u32's back from here:
	 * xid direction rpcversion prog vers proc flavour
	 */
	*rpcstart = p - 7;
	body_len = be32_to_cpup(p);
	if (body_len > RPC_MAX_AUTH_SIZE)
		return false;

	/* struct rpc_gss_cred_t */
	if (xdr_stream_decode_u32(xdr, &gc->gc_v) < 0)
		return false;
	if (xdr_stream_decode_u32(xdr, &gc->gc_proc) < 0)
		return false;
	if (xdr_stream_decode_u32(xdr, &gc->gc_seq) < 0)
		return false;
	if (xdr_stream_decode_u32(xdr, &gc->gc_svc) < 0)
		return false;
	handle_len = xdr_stream_decode_opaque_inline(xdr,
						     (void **)&gc->gc_ctx.data,
						     body_len);
	if (handle_len < 0)
		return false;
	if (body_len != XDR_UNIT * 5 + xdr_align_size(handle_len))
		return false;

	gc->gc_ctx.len = handle_len;
	return true;
}

/**
 * svcauth_gss_accept - Decode and validate incoming RPC_AUTH_GSS credential
 * @rqstp: RPC transaction
 *
 * Return values:
 *   %SVC_OK: Success
 *   %SVC_COMPLETE: GSS context lifetime event
 *   %SVC_DENIED: Credential or verifier is not valid
 *   %SVC_GARBAGE: Failed to decode credential or verifier
 *   %SVC_CLOSE: Temporary failure
 *
 * The rqstp->rq_auth_stat field is also set (see RFCs 2203 and 5531).
 */
static enum svc_auth_status
svcauth_gss_accept(struct svc_rqst *rqstp)
{
	struct gss_svc_data *svcdata = rqstp->rq_auth_data;
	__be32		*rpcstart;
	struct rpc_gss_wire_cred *gc;
	struct rsc	*rsci = NULL;
	int		ret;
	struct sunrpc_net *sn = net_generic(SVC_NET(rqstp), sunrpc_net_id);

	rqstp->rq_auth_stat = rpc_autherr_badcred;
	if (!svcdata)
		svcdata = kmalloc(sizeof(*svcdata), GFP_KERNEL);
	if (!svcdata)
		goto auth_err;
	rqstp->rq_auth_data = svcdata;
	svcdata->gsd_databody_offset = 0;
	svcdata->rsci = NULL;
	gc = &svcdata->clcred;

	if (!svcauth_gss_decode_credbody(&rqstp->rq_arg_stream, gc, &rpcstart))
		goto auth_err;
	if (gc->gc_v != RPC_GSS_VERSION)
		goto auth_err;

	switch (gc->gc_proc) {
	case RPC_GSS_PROC_INIT:
	case RPC_GSS_PROC_CONTINUE_INIT:
		if (rqstp->rq_proc != 0)
			goto auth_err;
		return svcauth_gss_proc_init(rqstp, gc);
	case RPC_GSS_PROC_DESTROY:
		if (rqstp->rq_proc != 0)
			goto auth_err;
		fallthrough;
	case RPC_GSS_PROC_DATA:
		rqstp->rq_auth_stat = rpcsec_gsserr_credproblem;
		rsci = gss_svc_searchbyctx(sn->rsc_cache, &gc->gc_ctx);
		if (!rsci)
			goto auth_err;
		switch (svcauth_gss_verify_header(rqstp, rsci, rpcstart, gc)) {
		case SVC_OK:
			break;
		case SVC_DENIED:
			goto auth_err;
		case SVC_DROP:
			goto drop;
		}
		break;
	default:
		if (rqstp->rq_proc != 0)
			goto auth_err;
		rqstp->rq_auth_stat = rpc_autherr_rejectedcred;
		goto auth_err;
	}

	/* now act upon the command: */
	switch (gc->gc_proc) {
	case RPC_GSS_PROC_DESTROY:
		if (!svcauth_gss_encode_verf(rqstp, rsci->mechctx, gc->gc_seq))
			goto auth_err;
		if (!svcxdr_set_accept_stat(rqstp))
			goto auth_err;
		/* Delete the entry from the cache_list and call cache_put */
		sunrpc_cache_unhash(sn->rsc_cache, &rsci->h);
		goto complete;
	case RPC_GSS_PROC_DATA:
		rqstp->rq_auth_stat = rpcsec_gsserr_ctxproblem;
		if (!svcauth_gss_encode_verf(rqstp, rsci->mechctx, gc->gc_seq))
			goto auth_err;
		if (!svcxdr_set_accept_stat(rqstp))
			goto auth_err;
		svcdata->gsd_databody_offset = xdr_stream_pos(&rqstp->rq_res_stream);
		rqstp->rq_cred = rsci->cred;
		get_group_info(rsci->cred.cr_group_info);
		rqstp->rq_auth_stat = rpc_autherr_badcred;
		switch (gc->gc_svc) {
		case RPC_GSS_SVC_NONE:
			break;
		case RPC_GSS_SVC_INTEGRITY:
			/* placeholders for body length and seq. number: */
			xdr_reserve_space(&rqstp->rq_res_stream, XDR_UNIT * 2);
			if (svcauth_gss_unwrap_integ(rqstp, gc->gc_seq,
						     rsci->mechctx))
				goto garbage_args;
			svcxdr_set_auth_slack(rqstp, RPC_MAX_AUTH_SIZE);
			break;
		case RPC_GSS_SVC_PRIVACY:
			/* placeholders for body length and seq. number: */
			xdr_reserve_space(&rqstp->rq_res_stream, XDR_UNIT * 2);
			if (svcauth_gss_unwrap_priv(rqstp, gc->gc_seq,
						    rsci->mechctx))
				goto garbage_args;
			svcxdr_set_auth_slack(rqstp, RPC_MAX_AUTH_SIZE * 2);
			break;
		default:
			goto auth_err;
		}
		svcdata->rsci = rsci;
		cache_get(&rsci->h);
		rqstp->rq_cred.cr_flavor = gss_svc_to_pseudoflavor(
					rsci->mechctx->mech_type,
					GSS_C_QOP_DEFAULT,
					gc->gc_svc);
		ret = SVC_OK;
		trace_rpcgss_svc_authenticate(rqstp, gc);
		goto out;
	}
garbage_args:
	ret = SVC_GARBAGE;
	goto out;
auth_err:
	xdr_truncate_encode(&rqstp->rq_res_stream, XDR_UNIT * 2);
	ret = SVC_DENIED;
	goto out;
complete:
	ret = SVC_COMPLETE;
	goto out;
drop:
	ret = SVC_CLOSE;
out:
	if (rsci)
		cache_put(&rsci->h, sn->rsc_cache);
	return ret;
}

static u32
svcauth_gss_prepare_to_wrap(struct svc_rqst *rqstp, struct gss_svc_data *gsd)
{
	u32 offset;

	/* Release can be called twice, but we only wrap once. */
	offset = gsd->gsd_databody_offset;
	gsd->gsd_databody_offset = 0;

	/* AUTH_ERROR replies are not wrapped. */
	if (rqstp->rq_auth_stat != rpc_auth_ok)
		return 0;

	/* Also don't wrap if the accept_stat is nonzero: */
	if (*rqstp->rq_accept_statp != rpc_success)
		return 0;

	return offset;
}

/*
 * RFC 2203, Section 5.3.2.2
 *
 *	struct rpc_gss_integ_data {
 *		opaque databody_integ<>;
 *		opaque checksum<>;
 *	};
 *
 *	struct rpc_gss_data_t {
 *		unsigned int seq_num;
 *		proc_req_arg_t arg;
 *	};
 *
 * The RPC Reply message has already been XDR-encoded. rq_res_stream
 * is now positioned so that the checksum can be written just past
 * the RPC Reply message.
 */
static int svcauth_gss_wrap_integ(struct svc_rqst *rqstp)
{
	struct gss_svc_data *gsd = rqstp->rq_auth_data;
	struct xdr_stream *xdr = &rqstp->rq_res_stream;
	struct rpc_gss_wire_cred *gc = &gsd->clcred;
	struct xdr_buf *buf = xdr->buf;
	struct xdr_buf databody_integ;
	struct xdr_netobj checksum;
	u32 offset, maj_stat;

	offset = svcauth_gss_prepare_to_wrap(rqstp, gsd);
	if (!offset)
		goto out;

	if (xdr_buf_subsegment(buf, &databody_integ, offset + XDR_UNIT,
			       buf->len - offset - XDR_UNIT))
		goto wrap_failed;
	/* Buffer space for these has already been reserved in
	 * svcauth_gss_accept(). */
	if (xdr_encode_word(buf, offset, databody_integ.len))
		goto wrap_failed;
	if (xdr_encode_word(buf, offset + XDR_UNIT, gc->gc_seq))
		goto wrap_failed;

	checksum.data = gsd->gsd_scratch;
	maj_stat = gss_get_mic(gsd->rsci->mechctx, &databody_integ, &checksum);
	if (maj_stat != GSS_S_COMPLETE)
		goto bad_mic;

	if (xdr_stream_encode_opaque(xdr, checksum.data, checksum.len) < 0)
		goto wrap_failed;
	xdr_commit_encode(xdr);

out:
	return 0;

bad_mic:
	trace_rpcgss_svc_get_mic(rqstp, maj_stat);
	return -EINVAL;
wrap_failed:
	trace_rpcgss_svc_wrap_failed(rqstp);
	return -EINVAL;
}

/*
 * RFC 2203, Section 5.3.2.3
 *
 *	struct rpc_gss_priv_data {
 *		opaque databody_priv<>
 *	};
 *
 *	struct rpc_gss_data_t {
 *		unsigned int seq_num;
 *		proc_req_arg_t arg;
 *	};
 *
 * gss_wrap() expands the size of the RPC message payload in the
 * response buffer. The main purpose of svcauth_gss_wrap_priv()
 * is to ensure there is adequate space in the response buffer to
 * avoid overflow during the wrap.
 */
static int svcauth_gss_wrap_priv(struct svc_rqst *rqstp)
{
	struct gss_svc_data *gsd = rqstp->rq_auth_data;
	struct rpc_gss_wire_cred *gc = &gsd->clcred;
	struct xdr_buf *buf = &rqstp->rq_res;
	struct kvec *head = buf->head;
	struct kvec *tail = buf->tail;
	u32 offset, pad, maj_stat;
	__be32 *p;

	offset = svcauth_gss_prepare_to_wrap(rqstp, gsd);
	if (!offset)
		return 0;

	/*
	 * Buffer space for this field has already been reserved
	 * in svcauth_gss_accept(). Note that the GSS sequence
	 * number is encrypted along with the RPC reply payload.
	 */
	if (xdr_encode_word(buf, offset + XDR_UNIT, gc->gc_seq))
		goto wrap_failed;

	/*
	 * If there is currently tail data, make sure there is
	 * room for the head, tail, and 2 * RPC_MAX_AUTH_SIZE in
	 * the page, and move the current tail data such that
	 * there is RPC_MAX_AUTH_SIZE slack space available in
	 * both the head and tail.
	 */
	if (tail->iov_base) {
		if (tail->iov_base >= head->iov_base + PAGE_SIZE)
			goto wrap_failed;
		if (tail->iov_base < head->iov_base)
			goto wrap_failed;
		if (tail->iov_len + head->iov_len
				+ 2 * RPC_MAX_AUTH_SIZE > PAGE_SIZE)
			goto wrap_failed;
		memmove(tail->iov_base + RPC_MAX_AUTH_SIZE, tail->iov_base,
			tail->iov_len);
		tail->iov_base += RPC_MAX_AUTH_SIZE;
	}
	/*
	 * If there is no current tail data, make sure there is
	 * room for the head data, and 2 * RPC_MAX_AUTH_SIZE in the
	 * allotted page, and set up tail information such that there
	 * is RPC_MAX_AUTH_SIZE slack space available in both the
	 * head and tail.
	 */
	if (!tail->iov_base) {
		if (head->iov_len + 2 * RPC_MAX_AUTH_SIZE > PAGE_SIZE)
			goto wrap_failed;
		tail->iov_base = head->iov_base
			+ head->iov_len + RPC_MAX_AUTH_SIZE;
		tail->iov_len = 0;
	}

	maj_stat = gss_wrap(gsd->rsci->mechctx, offset + XDR_UNIT, buf,
			    buf->pages);
	if (maj_stat != GSS_S_COMPLETE)
		goto bad_wrap;

	/* Wrapping can change the size of databody_priv. */
	if (xdr_encode_word(buf, offset, buf->len - offset - XDR_UNIT))
		goto wrap_failed;
	pad = xdr_pad_size(buf->len - offset - XDR_UNIT);
	p = (__be32 *)(tail->iov_base + tail->iov_len);
	memset(p, 0, pad);
	tail->iov_len += pad;
	buf->len += pad;

	return 0;
wrap_failed:
	trace_rpcgss_svc_wrap_failed(rqstp);
	return -EINVAL;
bad_wrap:
	trace_rpcgss_svc_wrap(rqstp, maj_stat);
	return -ENOMEM;
}

/**
 * svcauth_gss_release - Wrap payload and release resources
 * @rqstp: RPC transaction context
 *
 * Return values:
 *    %0: the Reply is ready to be sent
 *    %-ENOMEM: failed to allocate memory
 *    %-EINVAL: encoding error
 */
static int
svcauth_gss_release(struct svc_rqst *rqstp)
{
	struct sunrpc_net *sn = net_generic(SVC_NET(rqstp), sunrpc_net_id);
	struct gss_svc_data *gsd = rqstp->rq_auth_data;
	struct rpc_gss_wire_cred *gc;
	int stat;

	if (!gsd)
		goto out;
	gc = &gsd->clcred;
	if (gc->gc_proc != RPC_GSS_PROC_DATA)
		goto out;

	switch (gc->gc_svc) {
	case RPC_GSS_SVC_NONE:
		break;
	case RPC_GSS_SVC_INTEGRITY:
		stat = svcauth_gss_wrap_integ(rqstp);
		if (stat)
			goto out_err;
		break;
	case RPC_GSS_SVC_PRIVACY:
		stat = svcauth_gss_wrap_priv(rqstp);
		if (stat)
			goto out_err;
		break;
	/*
	 * For any other gc_svc value, svcauth_gss_accept() already set
	 * the auth_error appropriately; just fall through:
	 */
	}

out:
	stat = 0;
out_err:
	if (rqstp->rq_client)
		auth_domain_put(rqstp->rq_client);
	rqstp->rq_client = NULL;
	if (rqstp->rq_gssclient)
		auth_domain_put(rqstp->rq_gssclient);
	rqstp->rq_gssclient = NULL;
	if (rqstp->rq_cred.cr_group_info)
		put_group_info(rqstp->rq_cred.cr_group_info);
	rqstp->rq_cred.cr_group_info = NULL;
	if (gsd && gsd->rsci) {
		cache_put(&gsd->rsci->h, sn->rsc_cache);
		gsd->rsci = NULL;
	}
	return stat;
}

static void
svcauth_gss_domain_release_rcu(struct rcu_head *head)
{
	struct auth_domain *dom = container_of(head, struct auth_domain, rcu_head);
	struct gss_domain *gd = container_of(dom, struct gss_domain, h);

	kfree(dom->name);
	kfree(gd);
}

static void
svcauth_gss_domain_release(struct auth_domain *dom)
{
	call_rcu(&dom->rcu_head, svcauth_gss_domain_release_rcu);
}

static rpc_authflavor_t svcauth_gss_pseudoflavor(struct svc_rqst *rqstp)
{
	return svcauth_gss_flavor(rqstp->rq_gssclient);
}

static struct auth_ops svcauthops_gss = {
	.name		= "rpcsec_gss",
	.owner		= THIS_MODULE,
	.flavour	= RPC_AUTH_GSS,
	.accept		= svcauth_gss_accept,
	.release	= svcauth_gss_release,
	.domain_release = svcauth_gss_domain_release,
	.set_client	= svcauth_gss_set_client,
	.pseudoflavor	= svcauth_gss_pseudoflavor,
};

static int rsi_cache_create_net(struct net *net)
{
	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
	struct cache_detail *cd;
	int err;

	cd = cache_create_net(&rsi_cache_template, net);
	if (IS_ERR(cd))
		return PTR_ERR(cd);
	err = cache_register_net(cd, net);
	if (err) {
		cache_destroy_net(cd, net);
		return err;
	}
	sn->rsi_cache = cd;
	return 0;
}

static void rsi_cache_destroy_net(struct net *net)
{
	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
	struct cache_detail *cd = sn->rsi_cache;

	sn->rsi_cache = NULL;
	cache_purge(cd);
	cache_unregister_net(cd, net);
	cache_destroy_net(cd, net);
}

static int rsc_cache_create_net(struct net *net)
{
	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
	struct cache_detail *cd;
	int err;

	cd = cache_create_net(&rsc_cache_template, net);
	if (IS_ERR(cd))
		return PTR_ERR(cd);
	err = cache_register_net(cd, net);
	if (err) {
		cache_destroy_net(cd, net);
		return err;
	}
	sn->rsc_cache = cd;
	return 0;
}

static void rsc_cache_destroy_net(struct net *net)
{
	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
	struct cache_detail *cd = sn->rsc_cache;

	sn->rsc_cache = NULL;
	cache_purge(cd);
	cache_unregister_net(cd, net);
	cache_destroy_net(cd, net);
}

int
gss_svc_init_net(struct net *net)
{
	int rv;

	rv = rsc_cache_create_net(net);
	if (rv)
		return rv;
	rv = rsi_cache_create_net(net);
	if (rv)
		goto out1;
	rv = create_use_gss_proxy_proc_entry(net);
	if (rv)
		goto out2;

	rv = create_krb5_enctypes_proc_entry(net);
	if (rv)
		goto out3;

	return 0;

out3:
	destroy_use_gss_proxy_proc_entry(net);
out2:
	rsi_cache_destroy_net(net);
out1:
	rsc_cache_destroy_net(net);
	return rv;
}

void
gss_svc_shutdown_net(struct net *net)
{
	destroy_krb5_enctypes_proc_entry(net);
	destroy_use_gss_proxy_proc_entry(net);
	rsi_cache_destroy_net(net);
	rsc_cache_destroy_net(net);
}

int
gss_svc_init(void)
{
	return svc_auth_register(RPC_AUTH_GSS, &svcauthops_gss);
}

void
gss_svc_shutdown(void)
{
	svc_auth_unregister(RPC_AUTH_GSS);
}