aboutsummaryrefslogtreecommitdiff
path: root/crypto/vmac.c
blob: f50a85060b39f4359be9c05445bfd90735403a6f (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
/*
 * VMAC: Message Authentication Code using Universal Hashing
 *
 * Reference: https://tools.ietf.org/html/draft-krovetz-vmac-01
 *
 * Copyright (c) 2009, Intel Corporation.
 * Copyright (c) 2018, Google Inc.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
 * Place - Suite 330, Boston, MA 02111-1307 USA.
 */

/*
 * Derived from:
 *	VMAC and VHASH Implementation by Ted Krovetz (tdk@acm.org) and Wei Dai.
 *	This implementation is herby placed in the public domain.
 *	The authors offers no warranty. Use at your own risk.
 *	Last modified: 17 APR 08, 1700 PDT
 */

#include <asm/unaligned.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/crypto.h>
#include <linux/module.h>
#include <linux/scatterlist.h>
#include <asm/byteorder.h>
#include <crypto/scatterwalk.h>
#include <crypto/internal/hash.h>

/*
 * User definable settings.
 */
#define VMAC_TAG_LEN	64
#define VMAC_KEY_SIZE	128/* Must be 128, 192 or 256			*/
#define VMAC_KEY_LEN	(VMAC_KEY_SIZE/8)
#define VMAC_NHBYTES	128/* Must 2^i for any 3 < i < 13 Standard = 128*/
#define VMAC_NONCEBYTES	16

/* per-transform (per-key) context */
struct vmac_tfm_ctx {
	struct crypto_cipher *cipher;
	u64 nhkey[(VMAC_NHBYTES/8)+2*(VMAC_TAG_LEN/64-1)];
	u64 polykey[2*VMAC_TAG_LEN/64];
	u64 l3key[2*VMAC_TAG_LEN/64];
};

/* per-request context */
struct vmac_desc_ctx {
	union {
		u8 partial[VMAC_NHBYTES];	/* partial block */
		__le64 partial_words[VMAC_NHBYTES / 8];
	};
	unsigned int partial_size;	/* size of the partial block */
	bool first_block_processed;
	u64 polytmp[2*VMAC_TAG_LEN/64];	/* running total of L2-hash */
	union {
		u8 bytes[VMAC_NONCEBYTES];
		__be64 pads[VMAC_NONCEBYTES / 8];
	} nonce;
	unsigned int nonce_size; /* nonce bytes filled so far */
};

/*
 * Constants and masks
 */
#define UINT64_C(x) x##ULL
static const u64 p64   = UINT64_C(0xfffffffffffffeff);	/* 2^64 - 257 prime  */
static const u64 m62   = UINT64_C(0x3fffffffffffffff);	/* 62-bit mask       */
static const u64 m63   = UINT64_C(0x7fffffffffffffff);	/* 63-bit mask       */
static const u64 m64   = UINT64_C(0xffffffffffffffff);	/* 64-bit mask       */
static const u64 mpoly = UINT64_C(0x1fffffff1fffffff);	/* Poly key mask     */

#define pe64_to_cpup le64_to_cpup		/* Prefer little endian */

#ifdef __LITTLE_ENDIAN
#define INDEX_HIGH 1
#define INDEX_LOW 0
#else
#define INDEX_HIGH 0
#define INDEX_LOW 1
#endif

/*
 * The following routines are used in this implementation. They are
 * written via macros to simulate zero-overhead call-by-reference.
 *
 * MUL64: 64x64->128-bit multiplication
 * PMUL64: assumes top bits cleared on inputs
 * ADD128: 128x128->128-bit addition
 */

#define ADD128(rh, rl, ih, il)						\
	do {								\
		u64 _il = (il);						\
		(rl) += (_il);						\
		if ((rl) < (_il))					\
			(rh)++;						\
		(rh) += (ih);						\
	} while (0)

#define MUL32(i1, i2)	((u64)(u32)(i1)*(u32)(i2))

#define PMUL64(rh, rl, i1, i2)	/* Assumes m doesn't overflow */	\
	do {								\
		u64 _i1 = (i1), _i2 = (i2);				\
		u64 m = MUL32(_i1, _i2>>32) + MUL32(_i1>>32, _i2);	\
		rh = MUL32(_i1>>32, _i2>>32);				\
		rl = MUL32(_i1, _i2);					\
		ADD128(rh, rl, (m >> 32), (m << 32));			\
	} while (0)

#define MUL64(rh, rl, i1, i2)						\
	do {								\
		u64 _i1 = (i1), _i2 = (i2);				\
		u64 m1 = MUL32(_i1, _i2>>32);				\
		u64 m2 = MUL32(_i1>>32, _i2);				\
		rh = MUL32(_i1>>32, _i2>>32);				\
		rl = MUL32(_i1, _i2);					\
		ADD128(rh, rl, (m1 >> 32), (m1 << 32));			\
		ADD128(rh, rl, (m2 >> 32), (m2 << 32));			\
	} while (0)

/*
 * For highest performance the L1 NH and L2 polynomial hashes should be
 * carefully implemented to take advantage of one's target architecture.
 * Here these two hash functions are defined multiple time; once for
 * 64-bit architectures, once for 32-bit SSE2 architectures, and once
 * for the rest (32-bit) architectures.
 * For each, nh_16 *must* be defined (works on multiples of 16 bytes).
 * Optionally, nh_vmac_nhbytes can be defined (for multiples of
 * VMAC_NHBYTES), and nh_16_2 and nh_vmac_nhbytes_2 (versions that do two
 * NH computations at once).
 */

#ifdef CONFIG_64BIT

#define nh_16(mp, kp, nw, rh, rl)					\
	do {								\
		int i; u64 th, tl;					\
		rh = rl = 0;						\
		for (i = 0; i < nw; i += 2) {				\
			MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i],	\
				pe64_to_cpup((mp)+i+1)+(kp)[i+1]);	\
			ADD128(rh, rl, th, tl);				\
		}							\
	} while (0)

#define nh_16_2(mp, kp, nw, rh, rl, rh1, rl1)				\
	do {								\
		int i; u64 th, tl;					\
		rh1 = rl1 = rh = rl = 0;				\
		for (i = 0; i < nw; i += 2) {				\
			MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i],	\
				pe64_to_cpup((mp)+i+1)+(kp)[i+1]);	\
			ADD128(rh, rl, th, tl);				\
			MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i+2],	\
				pe64_to_cpup((mp)+i+1)+(kp)[i+3]);	\
			ADD128(rh1, rl1, th, tl);			\
		}							\
	} while (0)

#if (VMAC_NHBYTES >= 64) /* These versions do 64-bytes of message at a time */
#define nh_vmac_nhbytes(mp, kp, nw, rh, rl)				\
	do {								\
		int i; u64 th, tl;					\
		rh = rl = 0;						\
		for (i = 0; i < nw; i += 8) {				\
			MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i],	\
				pe64_to_cpup((mp)+i+1)+(kp)[i+1]);	\
			ADD128(rh, rl, th, tl);				\
			MUL64(th, tl, pe64_to_cpup((mp)+i+2)+(kp)[i+2],	\
				pe64_to_cpup((mp)+i+3)+(kp)[i+3]);	\
			ADD128(rh, rl, th, tl);				\
			MUL64(th, tl, pe64_to_cpup((mp)+i+4)+(kp)[i+4],	\
				pe64_to_cpup((mp)+i+5)+(kp)[i+5]);	\
			ADD128(rh, rl, th, tl);				\
			MUL64(th, tl, pe64_to_cpup((mp)+i+6)+(kp)[i+6],	\
				pe64_to_cpup((mp)+i+7)+(kp)[i+7]);	\
			ADD128(rh, rl, th, tl);				\
		}							\
	} while (0)

#define nh_vmac_nhbytes_2(mp, kp, nw, rh, rl, rh1, rl1)			\
	do {								\
		int i; u64 th, tl;					\
		rh1 = rl1 = rh = rl = 0;				\
		for (i = 0; i < nw; i += 8) {				\
			MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i],	\
				pe64_to_cpup((mp)+i+1)+(kp)[i+1]);	\
			ADD128(rh, rl, th, tl);				\
			MUL64(th, tl, pe64_to_cpup((mp)+i)+(kp)[i+2],	\
				pe64_to_cpup((mp)+i+1)+(kp)[i+3]);	\
			ADD128(rh1, rl1, th, tl);			\
			MUL64(th, tl, pe64_to_cpup((mp)+i+2)+(kp)[i+2],	\
				pe64_to_cpup((mp)+i+3)+(kp)[i+3]);	\
			ADD128(rh, rl, th, tl);				\
			MUL64(th, tl, pe64_to_cpup((mp)+i+2)+(kp)[i+4],	\
				pe64_to_cpup((mp)+i+3)+(kp)[i+5]);	\
			ADD128(rh1, rl1, th, tl);			\
			MUL64(th, tl, pe64_to_cpup((mp)+i+4)+(kp)[i+4],	\
				pe64_to_cpup((mp)+i+5)+(kp)[i+5]);	\
			ADD128(rh, rl, th, tl);				\
			MUL64(th, tl, pe64_to_cpup((mp)+i+4)+(kp)[i+6],	\
				pe64_to_cpup((mp)+i+5)+(kp)[i+7]);	\
			ADD128(rh1, rl1, th, tl);			\
			MUL64(th, tl, pe64_to_cpup((mp)+i+6)+(kp)[i+6],	\
				pe64_to_cpup((mp)+i+7)+(kp)[i+7]);	\
			ADD128(rh, rl, th, tl);				\
			MUL64(th, tl, pe64_to_cpup((mp)+i+6)+(kp)[i+8],	\
				pe64_to_cpup((mp)+i+7)+(kp)[i+9]);	\
			ADD128(rh1, rl1, th, tl);			\
		}							\
	} while (0)
#endif

#define poly_step(ah, al, kh, kl, mh, ml)				\
	do {								\
		u64 t1h, t1l, t2h, t2l, t3h, t3l, z = 0;		\
		/* compute ab*cd, put bd into result registers */	\
		PMUL64(t3h, t3l, al, kh);				\
		PMUL64(t2h, t2l, ah, kl);				\
		PMUL64(t1h, t1l, ah, 2*kh);				\
		PMUL64(ah, al, al, kl);					\
		/* add 2 * ac to result */				\
		ADD128(ah, al, t1h, t1l);				\
		/* add together ad + bc */				\
		ADD128(t2h, t2l, t3h, t3l);				\
		/* now (ah,al), (t2l,2*t2h) need summing */		\
		/* first add the high registers, carrying into t2h */	\
		ADD128(t2h, ah, z, t2l);				\
		/* double t2h and add top bit of ah */			\
		t2h = 2 * t2h + (ah >> 63);				\
		ah &= m63;						\
		/* now add the low registers */				\
		ADD128(ah, al, mh, ml);					\
		ADD128(ah, al, z, t2h);					\
	} while (0)

#else /* ! CONFIG_64BIT */

#ifndef nh_16
#define nh_16(mp, kp, nw, rh, rl)					\
	do {								\
		u64 t1, t2, m1, m2, t;					\
		int i;							\
		rh = rl = t = 0;					\
		for (i = 0; i < nw; i += 2)  {				\
			t1 = pe64_to_cpup(mp+i) + kp[i];		\
			t2 = pe64_to_cpup(mp+i+1) + kp[i+1];		\
			m2 = MUL32(t1 >> 32, t2);			\
			m1 = MUL32(t1, t2 >> 32);			\
			ADD128(rh, rl, MUL32(t1 >> 32, t2 >> 32),	\
				MUL32(t1, t2));				\
			rh += (u64)(u32)(m1 >> 32)			\
				+ (u32)(m2 >> 32);			\
			t += (u64)(u32)m1 + (u32)m2;			\
		}							\
		ADD128(rh, rl, (t >> 32), (t << 32));			\
	} while (0)
#endif

static void poly_step_func(u64 *ahi, u64 *alo,
			const u64 *kh, const u64 *kl,
			const u64 *mh, const u64 *ml)
{
#define a0 (*(((u32 *)alo)+INDEX_LOW))
#define a1 (*(((u32 *)alo)+INDEX_HIGH))
#define a2 (*(((u32 *)ahi)+INDEX_LOW))
#define a3 (*(((u32 *)ahi)+INDEX_HIGH))
#define k0 (*(((u32 *)kl)+INDEX_LOW))
#define k1 (*(((u32 *)kl)+INDEX_HIGH))
#define k2 (*(((u32 *)kh)+INDEX_LOW))
#define k3 (*(((u32 *)kh)+INDEX_HIGH))

	u64 p, q, t;
	u32 t2;

	p = MUL32(a3, k3);
	p += p;
	p += *(u64 *)mh;
	p += MUL32(a0, k2);
	p += MUL32(a1, k1);
	p += MUL32(a2, k0);
	t = (u32)(p);
	p >>= 32;
	p += MUL32(a0, k3);
	p += MUL32(a1, k2);
	p += MUL32(a2, k1);
	p += MUL32(a3, k0);
	t |= ((u64)((u32)p & 0x7fffffff)) << 32;
	p >>= 31;
	p += (u64)(((u32 *)ml)[INDEX_LOW]);
	p += MUL32(a0, k0);
	q =  MUL32(a1, k3);
	q += MUL32(a2, k2);
	q += MUL32(a3, k1);
	q += q;
	p += q;
	t2 = (u32)(p);
	p >>= 32;
	p += (u64)(((u32 *)ml)[INDEX_HIGH]);
	p += MUL32(a0, k1);
	p += MUL32(a1, k0);
	q =  MUL32(a2, k3);
	q += MUL32(a3, k2);
	q += q;
	p += q;
	*(u64 *)(alo) = (p << 32) | t2;
	p >>= 32;
	*(u64 *)(ahi) = p + t;

#undef a0
#undef a1
#undef a2
#undef a3
#undef k0
#undef k1
#undef k2
#undef k3
}

#define poly_step(ah, al, kh, kl, mh, ml)				\
	poly_step_func(&(ah), &(al), &(kh), &(kl), &(mh), &(ml))

#endif  /* end of specialized NH and poly definitions */

/* At least nh_16 is defined. Defined others as needed here */
#ifndef nh_16_2
#define nh_16_2(mp, kp, nw, rh, rl, rh2, rl2)				\
	do { 								\
		nh_16(mp, kp, nw, rh, rl);				\
		nh_16(mp, ((kp)+2), nw, rh2, rl2);			\
	} while (0)
#endif
#ifndef nh_vmac_nhbytes
#define nh_vmac_nhbytes(mp, kp, nw, rh, rl)				\
	nh_16(mp, kp, nw, rh, rl)
#endif
#ifndef nh_vmac_nhbytes_2
#define nh_vmac_nhbytes_2(mp, kp, nw, rh, rl, rh2, rl2)			\
	do {								\
		nh_vmac_nhbytes(mp, kp, nw, rh, rl);			\
		nh_vmac_nhbytes(mp, ((kp)+2), nw, rh2, rl2);		\
	} while (0)
#endif

static u64 l3hash(u64 p1, u64 p2, u64 k1, u64 k2, u64 len)
{
	u64 rh, rl, t, z = 0;

	/* fully reduce (p1,p2)+(len,0) mod p127 */
	t = p1 >> 63;
	p1 &= m63;
	ADD128(p1, p2, len, t);
	/* At this point, (p1,p2) is at most 2^127+(len<<64) */
	t = (p1 > m63) + ((p1 == m63) && (p2 == m64));
	ADD128(p1, p2, z, t);
	p1 &= m63;

	/* compute (p1,p2)/(2^64-2^32) and (p1,p2)%(2^64-2^32) */
	t = p1 + (p2 >> 32);
	t += (t >> 32);
	t += (u32)t > 0xfffffffeu;
	p1 += (t >> 32);
	p2 += (p1 << 32);

	/* compute (p1+k1)%p64 and (p2+k2)%p64 */
	p1 += k1;
	p1 += (0 - (p1 < k1)) & 257;
	p2 += k2;
	p2 += (0 - (p2 < k2)) & 257;

	/* compute (p1+k1)*(p2+k2)%p64 */
	MUL64(rh, rl, p1, p2);
	t = rh >> 56;
	ADD128(t, rl, z, rh);
	rh <<= 8;
	ADD128(t, rl, z, rh);
	t += t << 8;
	rl += t;
	rl += (0 - (rl < t)) & 257;
	rl += (0 - (rl > p64-1)) & 257;
	return rl;
}

/* L1 and L2-hash one or more VMAC_NHBYTES-byte blocks */
static void vhash_blocks(const struct vmac_tfm_ctx *tctx,
			 struct vmac_desc_ctx *dctx,
			 const __le64 *mptr, unsigned int blocks)
{
	const u64 *kptr = tctx->nhkey;
	const u64 pkh = tctx->polykey[0];
	const u64 pkl = tctx->polykey[1];
	u64 ch = dctx->polytmp[0];
	u64 cl = dctx->polytmp[1];
	u64 rh, rl;

	if (!dctx->first_block_processed) {
		dctx->first_block_processed = true;
		nh_vmac_nhbytes(mptr, kptr, VMAC_NHBYTES/8, rh, rl);
		rh &= m62;
		ADD128(ch, cl, rh, rl);
		mptr += (VMAC_NHBYTES/sizeof(u64));
		blocks--;
	}

	while (blocks--) {
		nh_vmac_nhbytes(mptr, kptr, VMAC_NHBYTES/8, rh, rl);
		rh &= m62;
		poly_step(ch, cl, pkh, pkl, rh, rl);
		mptr += (VMAC_NHBYTES/sizeof(u64));
	}

	dctx->polytmp[0] = ch;
	dctx->polytmp[1] = cl;
}

static int vmac_setkey(struct crypto_shash *tfm,
		       const u8 *key, unsigned int keylen)
{
	struct vmac_tfm_ctx *tctx = crypto_shash_ctx(tfm);
	__be64 out[2];
	u8 in[16] = { 0 };
	unsigned int i;
	int err;

	if (keylen != VMAC_KEY_LEN) {
		crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
		return -EINVAL;
	}

	err = crypto_cipher_setkey(tctx->cipher, key, keylen);
	if (err)
		return err;

	/* Fill nh key */
	in[0] = 0x80;
	for (i = 0; i < ARRAY_SIZE(tctx->nhkey); i += 2) {
		crypto_cipher_encrypt_one(tctx->cipher, (u8 *)out, in);
		tctx->nhkey[i] = be64_to_cpu(out[0]);
		tctx->nhkey[i+1] = be64_to_cpu(out[1]);
		in[15]++;
	}

	/* Fill poly key */
	in[0] = 0xC0;
	in[15] = 0;
	for (i = 0; i < ARRAY_SIZE(tctx->polykey); i += 2) {
		crypto_cipher_encrypt_one(tctx->cipher, (u8 *)out, in);
		tctx->polykey[i] = be64_to_cpu(out[0]) & mpoly;
		tctx->polykey[i+1] = be64_to_cpu(out[1]) & mpoly;
		in[15]++;
	}

	/* Fill ip key */
	in[0] = 0xE0;
	in[15] = 0;
	for (i = 0; i < ARRAY_SIZE(tctx->l3key); i += 2) {
		do {
			crypto_cipher_encrypt_one(tctx->cipher, (u8 *)out, in);
			tctx->l3key[i] = be64_to_cpu(out[0]);
			tctx->l3key[i+1] = be64_to_cpu(out[1]);
			in[15]++;
		} while (tctx->l3key[i] >= p64 || tctx->l3key[i+1] >= p64);
	}

	return 0;
}

static int vmac_init(struct shash_desc *desc)
{
	const struct vmac_tfm_ctx *tctx = crypto_shash_ctx(desc->tfm);
	struct vmac_desc_ctx *dctx = shash_desc_ctx(desc);

	dctx->partial_size = 0;
	dctx->first_block_processed = false;
	memcpy(dctx->polytmp, tctx->polykey, sizeof(dctx->polytmp));
	dctx->nonce_size = 0;
	return 0;
}

static int vmac_update(struct shash_desc *desc, const u8 *p, unsigned int len)
{
	const struct vmac_tfm_ctx *tctx = crypto_shash_ctx(desc->tfm);
	struct vmac_desc_ctx *dctx = shash_desc_ctx(desc);
	unsigned int n;

	/* Nonce is passed as first VMAC_NONCEBYTES bytes of data */
	if (dctx->nonce_size < VMAC_NONCEBYTES) {
		n = min(len, VMAC_NONCEBYTES - dctx->nonce_size);
		memcpy(&dctx->nonce.bytes[dctx->nonce_size], p, n);
		dctx->nonce_size += n;
		p += n;
		len -= n;
	}

	if (dctx->partial_size) {
		n = min(len, VMAC_NHBYTES - dctx->partial_size);
		memcpy(&dctx->partial[dctx->partial_size], p, n);
		dctx->partial_size += n;
		p += n;
		len -= n;
		if (dctx->partial_size == VMAC_NHBYTES) {
			vhash_blocks(tctx, dctx, dctx->partial_words, 1);
			dctx->partial_size = 0;
		}
	}

	if (len >= VMAC_NHBYTES) {
		n = round_down(len, VMAC_NHBYTES);
		/* TODO: 'p' may be misaligned here */
		vhash_blocks(tctx, dctx, (const __le64 *)p, n / VMAC_NHBYTES);
		p += n;
		len -= n;
	}

	if (len) {
		memcpy(dctx->partial, p, len);
		dctx->partial_size = len;
	}

	return 0;
}

static u64 vhash_final(const struct vmac_tfm_ctx *tctx,
		       struct vmac_desc_ctx *dctx)
{
	unsigned int partial = dctx->partial_size;
	u64 ch = dctx->polytmp[0];
	u64 cl = dctx->polytmp[1];

	/* L1 and L2-hash the final block if needed */
	if (partial) {
		/* Zero-pad to next 128-bit boundary */
		unsigned int n = round_up(partial, 16);
		u64 rh, rl;

		memset(&dctx->partial[partial], 0, n - partial);
		nh_16(dctx->partial_words, tctx->nhkey, n / 8, rh, rl);
		rh &= m62;
		if (dctx->first_block_processed)
			poly_step(ch, cl, tctx->polykey[0], tctx->polykey[1],
				  rh, rl);
		else
			ADD128(ch, cl, rh, rl);
	}

	/* L3-hash the 128-bit output of L2-hash */
	return l3hash(ch, cl, tctx->l3key[0], tctx->l3key[1], partial * 8);
}

static int vmac_final(struct shash_desc *desc, u8 *out)
{
	const struct vmac_tfm_ctx *tctx = crypto_shash_ctx(desc->tfm);
	struct vmac_desc_ctx *dctx = shash_desc_ctx(desc);
	int index;
	u64 hash, pad;

	if (dctx->nonce_size != VMAC_NONCEBYTES)
		return -EINVAL;

	/*
	 * The VMAC specification requires a nonce at least 1 bit shorter than
	 * the block cipher's block length, so we actually only accept a 127-bit
	 * nonce.  We define the unused bit to be the first one and require that
	 * it be 0, so the needed prepending of a 0 bit is implicit.
	 */
	if (dctx->nonce.bytes[0] & 0x80)
		return -EINVAL;

	/* Finish calculating the VHASH of the message */
	hash = vhash_final(tctx, dctx);

	/* Generate pseudorandom pad by encrypting the nonce */
	BUILD_BUG_ON(VMAC_NONCEBYTES != 2 * (VMAC_TAG_LEN / 8));
	index = dctx->nonce.bytes[VMAC_NONCEBYTES - 1] & 1;
	dctx->nonce.bytes[VMAC_NONCEBYTES - 1] &= ~1;
	crypto_cipher_encrypt_one(tctx->cipher, dctx->nonce.bytes,
				  dctx->nonce.bytes);
	pad = be64_to_cpu(dctx->nonce.pads[index]);

	/* The VMAC is the sum of VHASH and the pseudorandom pad */
	put_unaligned_be64(hash + pad, out);
	return 0;
}

static int vmac_init_tfm(struct crypto_tfm *tfm)
{
	struct crypto_instance *inst = crypto_tfm_alg_instance(tfm);
	struct crypto_spawn *spawn = crypto_instance_ctx(inst);
	struct vmac_tfm_ctx *tctx = crypto_tfm_ctx(tfm);
	struct crypto_cipher *cipher;

	cipher = crypto_spawn_cipher(spawn);
	if (IS_ERR(cipher))
		return PTR_ERR(cipher);

	tctx->cipher = cipher;
	return 0;
}

static void vmac_exit_tfm(struct crypto_tfm *tfm)
{
	struct vmac_tfm_ctx *tctx = crypto_tfm_ctx(tfm);

	crypto_free_cipher(tctx->cipher);
}

static int vmac_create(struct crypto_template *tmpl, struct rtattr **tb)
{
	struct shash_instance *inst;
	struct crypto_alg *alg;
	int err;

	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH);
	if (err)
		return err;

	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
			CRYPTO_ALG_TYPE_MASK);
	if (IS_ERR(alg))
		return PTR_ERR(alg);

	err = -EINVAL;
	if (alg->cra_blocksize != VMAC_NONCEBYTES)
		goto out_put_alg;

	inst = shash_alloc_instance(tmpl->name, alg);
	err = PTR_ERR(inst);
	if (IS_ERR(inst))
		goto out_put_alg;

	err = crypto_init_spawn(shash_instance_ctx(inst), alg,
			shash_crypto_instance(inst),
			CRYPTO_ALG_TYPE_MASK);
	if (err)
		goto out_free_inst;

	inst->alg.base.cra_priority = alg->cra_priority;
	inst->alg.base.cra_blocksize = alg->cra_blocksize;
	inst->alg.base.cra_alignmask = alg->cra_alignmask;

	inst->alg.base.cra_ctxsize = sizeof(struct vmac_tfm_ctx);
	inst->alg.base.cra_init = vmac_init_tfm;
	inst->alg.base.cra_exit = vmac_exit_tfm;

	inst->alg.descsize = sizeof(struct vmac_desc_ctx);
	inst->alg.digestsize = VMAC_TAG_LEN / 8;
	inst->alg.init = vmac_init;
	inst->alg.update = vmac_update;
	inst->alg.final = vmac_final;
	inst->alg.setkey = vmac_setkey;

	err = shash_register_instance(tmpl, inst);
	if (err) {
out_free_inst:
		shash_free_instance(shash_crypto_instance(inst));
	}

out_put_alg:
	crypto_mod_put(alg);
	return err;
}

static struct crypto_template vmac64_tmpl = {
	.name = "vmac64",
	.create = vmac_create,
	.free = shash_free_instance,
	.module = THIS_MODULE,
};

static int __init vmac_module_init(void)
{
	return crypto_register_template(&vmac64_tmpl);
}

static void __exit vmac_module_exit(void)
{
	crypto_unregister_template(&vmac64_tmpl);
}

subsys_initcall(vmac_module_init);
module_exit(vmac_module_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("VMAC hash algorithm");
MODULE_ALIAS_CRYPTO("vmac64");