summaryrefslogtreecommitdiffstats
path: root/net/sunrpc/auth_gss/gss_krb5_mech.c
blob: 75b3c2e9e8f8626857e8f97a32190090f25a4bcf (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
// SPDX-License-Identifier: BSD-3-Clause
/*
 *  linux/net/sunrpc/gss_krb5_mech.c
 *
 *  Copyright (c) 2001-2008 The Regents of the University of Michigan.
 *  All rights reserved.
 *
 *  Andy Adamson <andros@umich.edu>
 *  J. Bruce Fields <bfields@umich.edu>
 */

#include <crypto/hash.h>
#include <crypto/skcipher.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/sunrpc/auth.h>
#include <linux/sunrpc/gss_krb5.h>
#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/gss_krb5_enctypes.h>

#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
# define RPCDBG_FACILITY	RPCDBG_AUTH
#endif

static struct gss_api_mech gss_kerberos_mech;	/* forward declaration */

static const struct gss_krb5_enctype supported_gss_krb5_enctypes[] = {
#ifndef CONFIG_SUNRPC_DISABLE_INSECURE_ENCTYPES
	/*
	 * DES (All DES enctypes are mapped to the same gss functionality)
	 */
	{
	  .etype = ENCTYPE_DES_CBC_RAW,
	  .ctype = CKSUMTYPE_RSA_MD5,
	  .name = "des-cbc-crc",
	  .encrypt_name = "cbc(des)",
	  .cksum_name = "md5",
	  .encrypt = krb5_encrypt,
	  .decrypt = krb5_decrypt,
	  .mk_key = NULL,
	  .signalg = SGN_ALG_DES_MAC_MD5,
	  .sealalg = SEAL_ALG_DES,
	  .keybytes = 7,
	  .keylength = 8,
	  .blocksize = 8,
	  .conflen = 8,
	  .cksumlength = 8,
	  .keyed_cksum = 0,
	},
#endif	/* CONFIG_SUNRPC_DISABLE_INSECURE_ENCTYPES */
	/*
	 * RC4-HMAC
	 */
	{
	  .etype = ENCTYPE_ARCFOUR_HMAC,
	  .ctype = CKSUMTYPE_HMAC_MD5_ARCFOUR,
	  .name = "rc4-hmac",
	  .encrypt_name = "ecb(arc4)",
	  .cksum_name = "hmac(md5)",
	  .encrypt = krb5_encrypt,
	  .decrypt = krb5_decrypt,
	  .mk_key = NULL,
	  .signalg = SGN_ALG_HMAC_MD5,
	  .sealalg = SEAL_ALG_MICROSOFT_RC4,
	  .keybytes = 16,
	  .keylength = 16,
	  .blocksize = 1,
	  .conflen = 8,
	  .cksumlength = 8,
	  .keyed_cksum = 1,
	},
	/*
	 * 3DES
	 */
	{
	  .etype = ENCTYPE_DES3_CBC_RAW,
	  .ctype = CKSUMTYPE_HMAC_SHA1_DES3,
	  .name = "des3-hmac-sha1",
	  .encrypt_name = "cbc(des3_ede)",
	  .cksum_name = "hmac(sha1)",
	  .encrypt = krb5_encrypt,
	  .decrypt = krb5_decrypt,
	  .mk_key = gss_krb5_des3_make_key,
	  .signalg = SGN_ALG_HMAC_SHA1_DES3_KD,
	  .sealalg = SEAL_ALG_DES3KD,
	  .keybytes = 21,
	  .keylength = 24,
	  .blocksize = 8,
	  .conflen = 8,
	  .cksumlength = 20,
	  .keyed_cksum = 1,
	},
	/*
	 * AES128
	 */
	{
	  .etype = ENCTYPE_AES128_CTS_HMAC_SHA1_96,
	  .ctype = CKSUMTYPE_HMAC_SHA1_96_AES128,
	  .name = "aes128-cts",
	  .encrypt_name = "cts(cbc(aes))",
	  .cksum_name = "hmac(sha1)",
	  .encrypt = krb5_encrypt,
	  .decrypt = krb5_decrypt,
	  .mk_key = gss_krb5_aes_make_key,
	  .encrypt_v2 = gss_krb5_aes_encrypt,
	  .decrypt_v2 = gss_krb5_aes_decrypt,
	  .signalg = -1,
	  .sealalg = -1,
	  .keybytes = 16,
	  .keylength = 16,
	  .blocksize = 16,
	  .conflen = 16,
	  .cksumlength = 12,
	  .keyed_cksum = 1,
	},
	/*
	 * AES256
	 */
	{
	  .etype = ENCTYPE_AES256_CTS_HMAC_SHA1_96,
	  .ctype = CKSUMTYPE_HMAC_SHA1_96_AES256,
	  .name = "aes256-cts",
	  .encrypt_name = "cts(cbc(aes))",
	  .cksum_name = "hmac(sha1)",
	  .encrypt = krb5_encrypt,
	  .decrypt = krb5_decrypt,
	  .mk_key = gss_krb5_aes_make_key,
	  .encrypt_v2 = gss_krb5_aes_encrypt,
	  .decrypt_v2 = gss_krb5_aes_decrypt,
	  .signalg = -1,
	  .sealalg = -1,
	  .keybytes = 32,
	  .keylength = 32,
	  .blocksize = 16,
	  .conflen = 16,
	  .cksumlength = 12,
	  .keyed_cksum = 1,
	},
};

static const int num_supported_enctypes =
	ARRAY_SIZE(supported_gss_krb5_enctypes);

static int
supported_gss_krb5_enctype(int etype)
{
	int i;
	for (i = 0; i < num_supported_enctypes; i++)
		if (supported_gss_krb5_enctypes[i].etype == etype)
			return 1;
	return 0;
}

static const struct gss_krb5_enctype *
get_gss_krb5_enctype(int etype)
{
	int i;
	for (i = 0; i < num_supported_enctypes; i++)
		if (supported_gss_krb5_enctypes[i].etype == etype)
			return &supported_gss_krb5_enctypes[i];
	return NULL;
}

static const void *
simple_get_bytes(const void *p, const void *end, void *res, int len)
{
	const void *q = (const void *)((const char *)p + len);
	if (unlikely(q > end || q < p))
		return ERR_PTR(-EFAULT);
	memcpy(res, p, len);
	return q;
}

static const void *
simple_get_netobj(const void *p, const void *end, struct xdr_netobj *res)
{
	const void *q;
	unsigned int len;

	p = simple_get_bytes(p, end, &len, sizeof(len));
	if (IS_ERR(p))
		return p;
	q = (const void *)((const char *)p + len);
	if (unlikely(q > end || q < p))
		return ERR_PTR(-EFAULT);
	res->data = kmemdup(p, len, GFP_NOFS);
	if (unlikely(res->data == NULL))
		return ERR_PTR(-ENOMEM);
	res->len = len;
	return q;
}

static inline const void *
get_key(const void *p, const void *end,
	struct krb5_ctx *ctx, struct crypto_sync_skcipher **res)
{
	struct xdr_netobj	key;
	int			alg;

	p = simple_get_bytes(p, end, &alg, sizeof(alg));
	if (IS_ERR(p))
		goto out_err;

	switch (alg) {
	case ENCTYPE_DES_CBC_CRC:
	case ENCTYPE_DES_CBC_MD4:
	case ENCTYPE_DES_CBC_MD5:
		/* Map all these key types to ENCTYPE_DES_CBC_RAW */
		alg = ENCTYPE_DES_CBC_RAW;
		break;
	}

	if (!supported_gss_krb5_enctype(alg)) {
		printk(KERN_WARNING "gss_kerberos_mech: unsupported "
			"encryption key algorithm %d\n", alg);
		p = ERR_PTR(-EINVAL);
		goto out_err;
	}
	p = simple_get_netobj(p, end, &key);
	if (IS_ERR(p))
		goto out_err;

	*res = crypto_alloc_sync_skcipher(ctx->gk5e->encrypt_name, 0, 0);
	if (IS_ERR(*res)) {
		printk(KERN_WARNING "gss_kerberos_mech: unable to initialize "
			"crypto algorithm %s\n", ctx->gk5e->encrypt_name);
		*res = NULL;
		goto out_err_free_key;
	}
	if (crypto_sync_skcipher_setkey(*res, key.data, key.len)) {
		printk(KERN_WARNING "gss_kerberos_mech: error setting key for "
			"crypto algorithm %s\n", ctx->gk5e->encrypt_name);
		goto out_err_free_tfm;
	}

	kfree(key.data);
	return p;

out_err_free_tfm:
	crypto_free_sync_skcipher(*res);
out_err_free_key:
	kfree(key.data);
	p = ERR_PTR(-EINVAL);
out_err:
	return p;
}

static int
gss_import_v1_context(const void *p, const void *end, struct krb5_ctx *ctx)
{
	u32 seq_send;
	int tmp;
	u32 time32;

	p = simple_get_bytes(p, end, &ctx->initiate, sizeof(ctx->initiate));
	if (IS_ERR(p))
		goto out_err;

	/* Old format supports only DES!  Any other enctype uses new format */
	ctx->enctype = ENCTYPE_DES_CBC_RAW;

	ctx->gk5e = get_gss_krb5_enctype(ctx->enctype);
	if (ctx->gk5e == NULL) {
		p = ERR_PTR(-EINVAL);
		goto out_err;
	}

	/* The downcall format was designed before we completely understood
	 * the uses of the context fields; so it includes some stuff we
	 * just give some minimal sanity-checking, and some we ignore
	 * completely (like the next twenty bytes): */
	if (unlikely(p + 20 > end || p + 20 < p)) {
		p = ERR_PTR(-EFAULT);
		goto out_err;
	}
	p += 20;
	p = simple_get_bytes(p, end, &tmp, sizeof(tmp));
	if (IS_ERR(p))
		goto out_err;
	if (tmp != SGN_ALG_DES_MAC_MD5) {
		p = ERR_PTR(-ENOSYS);
		goto out_err;
	}
	p = simple_get_bytes(p, end, &tmp, sizeof(tmp));
	if (IS_ERR(p))
		goto out_err;
	if (tmp != SEAL_ALG_DES) {
		p = ERR_PTR(-ENOSYS);
		goto out_err;
	}
	p = simple_get_bytes(p, end, &time32, sizeof(time32));
	if (IS_ERR(p))
		goto out_err;
	/* unsigned 32-bit time overflows in year 2106 */
	ctx->endtime = (time64_t)time32;
	p = simple_get_bytes(p, end, &seq_send, sizeof(seq_send));
	if (IS_ERR(p))
		goto out_err;
	atomic_set(&ctx->seq_send, seq_send);
	p = simple_get_netobj(p, end, &ctx->mech_used);
	if (IS_ERR(p))
		goto out_err;
	p = get_key(p, end, ctx, &ctx->enc);
	if (IS_ERR(p))
		goto out_err_free_mech;
	p = get_key(p, end, ctx, &ctx->seq);
	if (IS_ERR(p))
		goto out_err_free_key1;
	if (p != end) {
		p = ERR_PTR(-EFAULT);
		goto out_err_free_key2;
	}

	return 0;

out_err_free_key2:
	crypto_free_sync_skcipher(ctx->seq);
out_err_free_key1:
	crypto_free_sync_skcipher(ctx->enc);
out_err_free_mech:
	kfree(ctx->mech_used.data);
out_err:
	return PTR_ERR(p);
}

static struct crypto_sync_skcipher *
context_v2_alloc_cipher(struct krb5_ctx *ctx, const char *cname, u8 *key)
{
	struct crypto_sync_skcipher *cp;

	cp = crypto_alloc_sync_skcipher(cname, 0, 0);
	if (IS_ERR(cp)) {
		dprintk("gss_kerberos_mech: unable to initialize "
			"crypto algorithm %s\n", cname);
		return NULL;
	}
	if (crypto_sync_skcipher_setkey(cp, key, ctx->gk5e->keylength)) {
		dprintk("gss_kerberos_mech: error setting key for "
			"crypto algorithm %s\n", cname);
		crypto_free_sync_skcipher(cp);
		return NULL;
	}
	return cp;
}

static inline void
set_cdata(u8 cdata[GSS_KRB5_K5CLENGTH], u32 usage, u8 seed)
{
	cdata[0] = (usage>>24)&0xff;
	cdata[1] = (usage>>16)&0xff;
	cdata[2] = (usage>>8)&0xff;
	cdata[3] = usage&0xff;
	cdata[4] = seed;
}

static int
context_derive_keys_des3(struct krb5_ctx *ctx, gfp_t gfp_mask)
{
	struct xdr_netobj c, keyin, keyout;
	u8 cdata[GSS_KRB5_K5CLENGTH];
	u32 err;

	c.len = GSS_KRB5_K5CLENGTH;
	c.data = cdata;

	keyin.data = ctx->Ksess;
	keyin.len = ctx->gk5e->keylength;
	keyout.len = ctx->gk5e->keylength;

	/* seq uses the raw key */
	ctx->seq = context_v2_alloc_cipher(ctx, ctx->gk5e->encrypt_name,
					   ctx->Ksess);
	if (ctx->seq == NULL)
		goto out_err;

	ctx->enc = context_v2_alloc_cipher(ctx, ctx->gk5e->encrypt_name,
					   ctx->Ksess);
	if (ctx->enc == NULL)
		goto out_free_seq;

	/* derive cksum */
	set_cdata(cdata, KG_USAGE_SIGN, KEY_USAGE_SEED_CHECKSUM);
	keyout.data = ctx->cksum;
	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
	if (err) {
		dprintk("%s: Error %d deriving cksum key\n",
			__func__, err);
		goto out_free_enc;
	}

	return 0;

out_free_enc:
	crypto_free_sync_skcipher(ctx->enc);
out_free_seq:
	crypto_free_sync_skcipher(ctx->seq);
out_err:
	return -EINVAL;
}

/*
 * Note that RC4 depends on deriving keys using the sequence
 * number or the checksum of a token.  Therefore, the final keys
 * cannot be calculated until the token is being constructed!
 */
static int
context_derive_keys_rc4(struct krb5_ctx *ctx)
{
	struct crypto_shash *hmac;
	char sigkeyconstant[] = "signaturekey";
	int slen = strlen(sigkeyconstant) + 1;	/* include null terminator */
	struct shash_desc *desc;
	int err;

	dprintk("RPC:       %s: entered\n", __func__);
	/*
	 * derive cksum (aka Ksign) key
	 */
	hmac = crypto_alloc_shash(ctx->gk5e->cksum_name, 0, 0);
	if (IS_ERR(hmac)) {
		dprintk("%s: error %ld allocating hash '%s'\n",
			__func__, PTR_ERR(hmac), ctx->gk5e->cksum_name);
		err = PTR_ERR(hmac);
		goto out_err;
	}

	err = crypto_shash_setkey(hmac, ctx->Ksess, ctx->gk5e->keylength);
	if (err)
		goto out_err_free_hmac;


	desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(hmac), GFP_NOFS);
	if (!desc) {
		dprintk("%s: failed to allocate hash descriptor for '%s'\n",
			__func__, ctx->gk5e->cksum_name);
		err = -ENOMEM;
		goto out_err_free_hmac;
	}

	desc->tfm = hmac;

	err = crypto_shash_digest(desc, sigkeyconstant, slen, ctx->cksum);
	kzfree(desc);
	if (err)
		goto out_err_free_hmac;
	/*
	 * allocate hash, and skciphers for data and seqnum encryption
	 */
	ctx->enc = crypto_alloc_sync_skcipher(ctx->gk5e->encrypt_name, 0, 0);
	if (IS_ERR(ctx->enc)) {
		err = PTR_ERR(ctx->enc);
		goto out_err_free_hmac;
	}

	ctx->seq = crypto_alloc_sync_skcipher(ctx->gk5e->encrypt_name, 0, 0);
	if (IS_ERR(ctx->seq)) {
		crypto_free_sync_skcipher(ctx->enc);
		err = PTR_ERR(ctx->seq);
		goto out_err_free_hmac;
	}

	dprintk("RPC:       %s: returning success\n", __func__);

	err = 0;

out_err_free_hmac:
	crypto_free_shash(hmac);
out_err:
	dprintk("RPC:       %s: returning %d\n", __func__, err);
	return err;
}

static int
context_derive_keys_new(struct krb5_ctx *ctx, gfp_t gfp_mask)
{
	struct xdr_netobj c, keyin, keyout;
	u8 cdata[GSS_KRB5_K5CLENGTH];
	u32 err;

	c.len = GSS_KRB5_K5CLENGTH;
	c.data = cdata;

	keyin.data = ctx->Ksess;
	keyin.len = ctx->gk5e->keylength;
	keyout.len = ctx->gk5e->keylength;

	/* initiator seal encryption */
	set_cdata(cdata, KG_USAGE_INITIATOR_SEAL, KEY_USAGE_SEED_ENCRYPTION);
	keyout.data = ctx->initiator_seal;
	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
	if (err) {
		dprintk("%s: Error %d deriving initiator_seal key\n",
			__func__, err);
		goto out_err;
	}
	ctx->initiator_enc = context_v2_alloc_cipher(ctx,
						     ctx->gk5e->encrypt_name,
						     ctx->initiator_seal);
	if (ctx->initiator_enc == NULL)
		goto out_err;

	/* acceptor seal encryption */
	set_cdata(cdata, KG_USAGE_ACCEPTOR_SEAL, KEY_USAGE_SEED_ENCRYPTION);
	keyout.data = ctx->acceptor_seal;
	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
	if (err) {
		dprintk("%s: Error %d deriving acceptor_seal key\n",
			__func__, err);
		goto out_free_initiator_enc;
	}
	ctx->acceptor_enc = context_v2_alloc_cipher(ctx,
						    ctx->gk5e->encrypt_name,
						    ctx->acceptor_seal);
	if (ctx->acceptor_enc == NULL)
		goto out_free_initiator_enc;

	/* initiator sign checksum */
	set_cdata(cdata, KG_USAGE_INITIATOR_SIGN, KEY_USAGE_SEED_CHECKSUM);
	keyout.data = ctx->initiator_sign;
	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
	if (err) {
		dprintk("%s: Error %d deriving initiator_sign key\n",
			__func__, err);
		goto out_free_acceptor_enc;
	}

	/* acceptor sign checksum */
	set_cdata(cdata, KG_USAGE_ACCEPTOR_SIGN, KEY_USAGE_SEED_CHECKSUM);
	keyout.data = ctx->acceptor_sign;
	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
	if (err) {
		dprintk("%s: Error %d deriving acceptor_sign key\n",
			__func__, err);
		goto out_free_acceptor_enc;
	}

	/* initiator seal integrity */
	set_cdata(cdata, KG_USAGE_INITIATOR_SEAL, KEY_USAGE_SEED_INTEGRITY);
	keyout.data = ctx->initiator_integ;
	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
	if (err) {
		dprintk("%s: Error %d deriving initiator_integ key\n",
			__func__, err);
		goto out_free_acceptor_enc;
	}

	/* acceptor seal integrity */
	set_cdata(cdata, KG_USAGE_ACCEPTOR_SEAL, KEY_USAGE_SEED_INTEGRITY);
	keyout.data = ctx->acceptor_integ;
	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
	if (err) {
		dprintk("%s: Error %d deriving acceptor_integ key\n",
			__func__, err);
		goto out_free_acceptor_enc;
	}

	switch (ctx->enctype) {
	case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
	case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
		ctx->initiator_enc_aux =
			context_v2_alloc_cipher(ctx, "cbc(aes)",
						ctx->initiator_seal);
		if (ctx->initiator_enc_aux == NULL)
			goto out_free_acceptor_enc;
		ctx->acceptor_enc_aux =
			context_v2_alloc_cipher(ctx, "cbc(aes)",
						ctx->acceptor_seal);
		if (ctx->acceptor_enc_aux == NULL) {
			crypto_free_sync_skcipher(ctx->initiator_enc_aux);
			goto out_free_acceptor_enc;
		}
	}

	return 0;

out_free_acceptor_enc:
	crypto_free_sync_skcipher(ctx->acceptor_enc);
out_free_initiator_enc:
	crypto_free_sync_skcipher(ctx->initiator_enc);
out_err:
	return -EINVAL;
}

static int
gss_import_v2_context(const void *p, const void *end, struct krb5_ctx *ctx,
		gfp_t gfp_mask)
{
	u64 seq_send64;
	int keylen;
	u32 time32;

	p = simple_get_bytes(p, end, &ctx->flags, sizeof(ctx->flags));
	if (IS_ERR(p))
		goto out_err;
	ctx->initiate = ctx->flags & KRB5_CTX_FLAG_INITIATOR;

	p = simple_get_bytes(p, end, &time32, sizeof(time32));
	if (IS_ERR(p))
		goto out_err;
	/* unsigned 32-bit time overflows in year 2106 */
	ctx->endtime = (time64_t)time32;
	p = simple_get_bytes(p, end, &seq_send64, sizeof(seq_send64));
	if (IS_ERR(p))
		goto out_err;
	atomic64_set(&ctx->seq_send64, seq_send64);
	/* set seq_send for use by "older" enctypes */
	atomic_set(&ctx->seq_send, seq_send64);
	if (seq_send64 != atomic_read(&ctx->seq_send)) {
		dprintk("%s: seq_send64 %llx, seq_send %x overflow?\n", __func__,
			seq_send64, atomic_read(&ctx->seq_send));
		p = ERR_PTR(-EINVAL);
		goto out_err;
	}
	p = simple_get_bytes(p, end, &ctx->enctype, sizeof(ctx->enctype));
	if (IS_ERR(p))
		goto out_err;
	/* Map ENCTYPE_DES3_CBC_SHA1 to ENCTYPE_DES3_CBC_RAW */
	if (ctx->enctype == ENCTYPE_DES3_CBC_SHA1)
		ctx->enctype = ENCTYPE_DES3_CBC_RAW;
	ctx->gk5e = get_gss_krb5_enctype(ctx->enctype);
	if (ctx->gk5e == NULL) {
		dprintk("gss_kerberos_mech: unsupported krb5 enctype %u\n",
			ctx->enctype);
		p = ERR_PTR(-EINVAL);
		goto out_err;
	}
	keylen = ctx->gk5e->keylength;

	p = simple_get_bytes(p, end, ctx->Ksess, keylen);
	if (IS_ERR(p))
		goto out_err;

	if (p != end) {
		p = ERR_PTR(-EINVAL);
		goto out_err;
	}

	ctx->mech_used.data = kmemdup(gss_kerberos_mech.gm_oid.data,
				      gss_kerberos_mech.gm_oid.len, gfp_mask);
	if (unlikely(ctx->mech_used.data == NULL)) {
		p = ERR_PTR(-ENOMEM);
		goto out_err;
	}
	ctx->mech_used.len = gss_kerberos_mech.gm_oid.len;

	switch (ctx->enctype) {
	case ENCTYPE_DES3_CBC_RAW:
		return context_derive_keys_des3(ctx, gfp_mask);
	case ENCTYPE_ARCFOUR_HMAC:
		return context_derive_keys_rc4(ctx);
	case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
	case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
		return context_derive_keys_new(ctx, gfp_mask);
	default:
		return -EINVAL;
	}

out_err:
	return PTR_ERR(p);
}

static int
gss_import_sec_context_kerberos(const void *p, size_t len,
				struct gss_ctx *ctx_id,
				time64_t *endtime,
				gfp_t gfp_mask)
{
	const void *end = (const void *)((const char *)p + len);
	struct  krb5_ctx *ctx;
	int ret;

	ctx = kzalloc(sizeof(*ctx), gfp_mask);
	if (ctx == NULL)
		return -ENOMEM;

	if (len == 85)
		ret = gss_import_v1_context(p, end, ctx);
	else
		ret = gss_import_v2_context(p, end, ctx, gfp_mask);

	if (ret == 0) {
		ctx_id->internal_ctx_id = ctx;
		if (endtime)
			*endtime = ctx->endtime;
	} else
		kfree(ctx);

	dprintk("RPC:       %s: returning %d\n", __func__, ret);
	return ret;
}

static void
gss_delete_sec_context_kerberos(void *internal_ctx) {
	struct krb5_ctx *kctx = internal_ctx;

	crypto_free_sync_skcipher(kctx->seq);
	crypto_free_sync_skcipher(kctx->enc);
	crypto_free_sync_skcipher(kctx->acceptor_enc);
	crypto_free_sync_skcipher(kctx->initiator_enc);
	crypto_free_sync_skcipher(kctx->acceptor_enc_aux);
	crypto_free_sync_skcipher(kctx->initiator_enc_aux);
	kfree(kctx->mech_used.data);
	kfree(kctx);
}

static const struct gss_api_ops gss_kerberos_ops = {
	.gss_import_sec_context	= gss_import_sec_context_kerberos,
	.gss_get_mic		= gss_get_mic_kerberos,
	.gss_verify_mic		= gss_verify_mic_kerberos,
	.gss_wrap		= gss_wrap_kerberos,
	.gss_unwrap		= gss_unwrap_kerberos,
	.gss_delete_sec_context	= gss_delete_sec_context_kerberos,
};

static struct pf_desc gss_kerberos_pfs[] = {
	[0] = {
		.pseudoflavor = RPC_AUTH_GSS_KRB5,
		.qop = GSS_C_QOP_DEFAULT,
		.service = RPC_GSS_SVC_NONE,
		.name = "krb5",
	},
	[1] = {
		.pseudoflavor = RPC_AUTH_GSS_KRB5I,
		.qop = GSS_C_QOP_DEFAULT,
		.service = RPC_GSS_SVC_INTEGRITY,
		.name = "krb5i",
		.datatouch = true,
	},
	[2] = {
		.pseudoflavor = RPC_AUTH_GSS_KRB5P,
		.qop = GSS_C_QOP_DEFAULT,
		.service = RPC_GSS_SVC_PRIVACY,
		.name = "krb5p",
		.datatouch = true,
	},
};

MODULE_ALIAS("rpc-auth-gss-krb5");
MODULE_ALIAS("rpc-auth-gss-krb5i");
MODULE_ALIAS("rpc-auth-gss-krb5p");
MODULE_ALIAS("rpc-auth-gss-390003");
MODULE_ALIAS("rpc-auth-gss-390004");
MODULE_ALIAS("rpc-auth-gss-390005");
MODULE_ALIAS("rpc-auth-gss-1.2.840.113554.1.2.2");

static struct gss_api_mech gss_kerberos_mech = {
	.gm_name	= "krb5",
	.gm_owner	= THIS_MODULE,
	.gm_oid		= { 9, "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02" },
	.gm_ops		= &gss_kerberos_ops,
	.gm_pf_num	= ARRAY_SIZE(gss_kerberos_pfs),
	.gm_pfs		= gss_kerberos_pfs,
	.gm_upcall_enctypes = KRB5_SUPPORTED_ENCTYPES,
};

static int __init init_kerberos_module(void)
{
	int status;

	status = gss_mech_register(&gss_kerberos_mech);
	if (status)
		printk("Failed to register kerberos gss mechanism!\n");
	return status;
}

static void __exit cleanup_kerberos_module(void)
{
	gss_mech_unregister(&gss_kerberos_mech);
}

MODULE_LICENSE("GPL");
module_init(init_kerberos_module);
module_exit(cleanup_kerberos_module);