summaryrefslogtreecommitdiff
path: root/crypto/chacha20poly1305.c
blob: b71445f282ad2ac62d23a0dee095d67572e12de3 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
/*
 * ChaCha20-Poly1305 AEAD, RFC7539
 *
 * Copyright (C) 2015 Martin Willi
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <crypto/internal/aead.h>
#include <crypto/internal/hash.h>
#include <crypto/internal/skcipher.h>
#include <crypto/scatterwalk.h>
#include <crypto/chacha20.h>
#include <crypto/poly1305.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>

#include "internal.h"

#define CHACHAPOLY_IV_SIZE	12

struct chachapoly_instance_ctx {
	struct crypto_skcipher_spawn chacha;
	struct crypto_ahash_spawn poly;
	unsigned int saltlen;
};

struct chachapoly_ctx {
	struct crypto_ablkcipher *chacha;
	struct crypto_ahash *poly;
	/* key bytes we use for the ChaCha20 IV */
	unsigned int saltlen;
	u8 salt[];
};

struct poly_req {
	/* zero byte padding for AD/ciphertext, as needed */
	u8 pad[POLY1305_BLOCK_SIZE];
	/* tail data with AD/ciphertext lengths */
	struct {
		__le64 assoclen;
		__le64 cryptlen;
	} tail;
	struct scatterlist src[1];
	struct ahash_request req; /* must be last member */
};

struct chacha_req {
	u8 iv[CHACHA20_IV_SIZE];
	struct scatterlist src[1];
	struct ablkcipher_request req; /* must be last member */
};

struct chachapoly_req_ctx {
	struct scatterlist src[2];
	struct scatterlist dst[2];
	/* the key we generate for Poly1305 using Chacha20 */
	u8 key[POLY1305_KEY_SIZE];
	/* calculated Poly1305 tag */
	u8 tag[POLY1305_DIGEST_SIZE];
	/* length of data to en/decrypt, without ICV */
	unsigned int cryptlen;
	/* Actual AD, excluding IV */
	unsigned int assoclen;
	union {
		struct poly_req poly;
		struct chacha_req chacha;
	} u;
};

static inline void async_done_continue(struct aead_request *req, int err,
				       int (*cont)(struct aead_request *))
{
	if (!err)
		err = cont(req);

	if (err != -EINPROGRESS && err != -EBUSY)
		aead_request_complete(req, err);
}

static void chacha_iv(u8 *iv, struct aead_request *req, u32 icb)
{
	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
	__le32 leicb = cpu_to_le32(icb);

	memcpy(iv, &leicb, sizeof(leicb));
	memcpy(iv + sizeof(leicb), ctx->salt, ctx->saltlen);
	memcpy(iv + sizeof(leicb) + ctx->saltlen, req->iv,
	       CHACHA20_IV_SIZE - sizeof(leicb) - ctx->saltlen);
}

static int poly_verify_tag(struct aead_request *req)
{
	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
	u8 tag[sizeof(rctx->tag)];

	scatterwalk_map_and_copy(tag, req->src,
				 req->assoclen + rctx->cryptlen,
				 sizeof(tag), 0);
	if (crypto_memneq(tag, rctx->tag, sizeof(tag)))
		return -EBADMSG;
	return 0;
}

static int poly_copy_tag(struct aead_request *req)
{
	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);

	scatterwalk_map_and_copy(rctx->tag, req->dst,
				 req->assoclen + rctx->cryptlen,
				 sizeof(rctx->tag), 1);
	return 0;
}

static void chacha_decrypt_done(struct crypto_async_request *areq, int err)
{
	async_done_continue(areq->data, err, poly_verify_tag);
}

static int chacha_decrypt(struct aead_request *req)
{
	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
	struct chacha_req *creq = &rctx->u.chacha;
	struct scatterlist *src, *dst;
	int err;

	chacha_iv(creq->iv, req, 1);

	sg_init_table(rctx->src, 2);
	src = scatterwalk_ffwd(rctx->src, req->src, req->assoclen);
	dst = src;

	if (req->src != req->dst) {
		sg_init_table(rctx->dst, 2);
		dst = scatterwalk_ffwd(rctx->dst, req->dst, req->assoclen);
	}

	ablkcipher_request_set_callback(&creq->req, aead_request_flags(req),
					chacha_decrypt_done, req);
	ablkcipher_request_set_tfm(&creq->req, ctx->chacha);
	ablkcipher_request_set_crypt(&creq->req, src, dst,
				     rctx->cryptlen, creq->iv);
	err = crypto_ablkcipher_decrypt(&creq->req);
	if (err)
		return err;

	return poly_verify_tag(req);
}

static int poly_tail_continue(struct aead_request *req)
{
	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);

	if (rctx->cryptlen == req->cryptlen) /* encrypting */
		return poly_copy_tag(req);

	return chacha_decrypt(req);
}

static void poly_tail_done(struct crypto_async_request *areq, int err)
{
	async_done_continue(areq->data, err, poly_tail_continue);
}

static int poly_tail(struct aead_request *req)
{
	struct crypto_aead *tfm = crypto_aead_reqtfm(req);
	struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
	struct poly_req *preq = &rctx->u.poly;
	__le64 len;
	int err;

	sg_init_table(preq->src, 1);
	len = cpu_to_le64(rctx->assoclen);
	memcpy(&preq->tail.assoclen, &len, sizeof(len));
	len = cpu_to_le64(rctx->cryptlen);
	memcpy(&preq->tail.cryptlen, &len, sizeof(len));
	sg_set_buf(preq->src, &preq->tail, sizeof(preq->tail));

	ahash_request_set_callback(&preq->req, aead_request_flags(req),
				   poly_tail_done, req);
	ahash_request_set_tfm(&preq->req, ctx->poly);
	ahash_request_set_crypt(&preq->req, preq->src,
				rctx->tag, sizeof(preq->tail));

	err = crypto_ahash_finup(&preq->req);
	if (err)
		return err;

	return poly_tail_continue(req);
}

static void poly_cipherpad_done(struct crypto_async_request *areq, int err)
{
	async_done_continue(areq->data, err, poly_tail);
}

static int poly_cipherpad(struct aead_request *req)
{
	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
	struct poly_req *preq = &rctx->u.poly;
	unsigned int padlen, bs = POLY1305_BLOCK_SIZE;
	int err;

	padlen = (bs - (rctx->cryptlen % bs)) % bs;
	memset(preq->pad, 0, sizeof(preq->pad));
	sg_init_table(preq->src, 1);
	sg_set_buf(preq->src, &preq->pad, padlen);

	ahash_request_set_callback(&preq->req, aead_request_flags(req),
				   poly_cipherpad_done, req);
	ahash_request_set_tfm(&preq->req, ctx->poly);
	ahash_request_set_crypt(&preq->req, preq->src, NULL, padlen);

	err = crypto_ahash_update(&preq->req);
	if (err)
		return err;

	return poly_tail(req);
}

static void poly_cipher_done(struct crypto_async_request *areq, int err)
{
	async_done_continue(areq->data, err, poly_cipherpad);
}

static int poly_cipher(struct aead_request *req)
{
	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
	struct poly_req *preq = &rctx->u.poly;
	struct scatterlist *crypt = req->src;
	int err;

	if (rctx->cryptlen == req->cryptlen) /* encrypting */
		crypt = req->dst;

	sg_init_table(rctx->src, 2);
	crypt = scatterwalk_ffwd(rctx->src, crypt, req->assoclen);

	ahash_request_set_callback(&preq->req, aead_request_flags(req),
				   poly_cipher_done, req);
	ahash_request_set_tfm(&preq->req, ctx->poly);
	ahash_request_set_crypt(&preq->req, crypt, NULL, rctx->cryptlen);

	err = crypto_ahash_update(&preq->req);
	if (err)
		return err;

	return poly_cipherpad(req);
}

static void poly_adpad_done(struct crypto_async_request *areq, int err)
{
	async_done_continue(areq->data, err, poly_cipher);
}

static int poly_adpad(struct aead_request *req)
{
	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
	struct poly_req *preq = &rctx->u.poly;
	unsigned int padlen, bs = POLY1305_BLOCK_SIZE;
	int err;

	padlen = (bs - (rctx->assoclen % bs)) % bs;
	memset(preq->pad, 0, sizeof(preq->pad));
	sg_init_table(preq->src, 1);
	sg_set_buf(preq->src, preq->pad, padlen);

	ahash_request_set_callback(&preq->req, aead_request_flags(req),
				   poly_adpad_done, req);
	ahash_request_set_tfm(&preq->req, ctx->poly);
	ahash_request_set_crypt(&preq->req, preq->src, NULL, padlen);

	err = crypto_ahash_update(&preq->req);
	if (err)
		return err;

	return poly_cipher(req);
}

static void poly_ad_done(struct crypto_async_request *areq, int err)
{
	async_done_continue(areq->data, err, poly_adpad);
}

static int poly_ad(struct aead_request *req)
{
	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
	struct poly_req *preq = &rctx->u.poly;
	int err;

	ahash_request_set_callback(&preq->req, aead_request_flags(req),
				   poly_ad_done, req);
	ahash_request_set_tfm(&preq->req, ctx->poly);
	ahash_request_set_crypt(&preq->req, req->src, NULL, rctx->assoclen);

	err = crypto_ahash_update(&preq->req);
	if (err)
		return err;

	return poly_adpad(req);
}

static void poly_setkey_done(struct crypto_async_request *areq, int err)
{
	async_done_continue(areq->data, err, poly_ad);
}

static int poly_setkey(struct aead_request *req)
{
	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
	struct poly_req *preq = &rctx->u.poly;
	int err;

	sg_init_table(preq->src, 1);
	sg_set_buf(preq->src, rctx->key, sizeof(rctx->key));

	ahash_request_set_callback(&preq->req, aead_request_flags(req),
				   poly_setkey_done, req);
	ahash_request_set_tfm(&preq->req, ctx->poly);
	ahash_request_set_crypt(&preq->req, preq->src, NULL, sizeof(rctx->key));

	err = crypto_ahash_update(&preq->req);
	if (err)
		return err;

	return poly_ad(req);
}

static void poly_init_done(struct crypto_async_request *areq, int err)
{
	async_done_continue(areq->data, err, poly_setkey);
}

static int poly_init(struct aead_request *req)
{
	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
	struct poly_req *preq = &rctx->u.poly;
	int err;

	ahash_request_set_callback(&preq->req, aead_request_flags(req),
				   poly_init_done, req);
	ahash_request_set_tfm(&preq->req, ctx->poly);

	err = crypto_ahash_init(&preq->req);
	if (err)
		return err;

	return poly_setkey(req);
}

static void poly_genkey_done(struct crypto_async_request *areq, int err)
{
	async_done_continue(areq->data, err, poly_init);
}

static int poly_genkey(struct aead_request *req)
{
	struct crypto_aead *tfm = crypto_aead_reqtfm(req);
	struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
	struct chacha_req *creq = &rctx->u.chacha;
	int err;

	rctx->assoclen = req->assoclen;

	if (crypto_aead_ivsize(tfm) == 8) {
		if (rctx->assoclen < 8)
			return -EINVAL;
		rctx->assoclen -= 8;
	}

	sg_init_table(creq->src, 1);
	memset(rctx->key, 0, sizeof(rctx->key));
	sg_set_buf(creq->src, rctx->key, sizeof(rctx->key));

	chacha_iv(creq->iv, req, 0);

	ablkcipher_request_set_callback(&creq->req, aead_request_flags(req),
					poly_genkey_done, req);
	ablkcipher_request_set_tfm(&creq->req, ctx->chacha);
	ablkcipher_request_set_crypt(&creq->req, creq->src, creq->src,
				     POLY1305_KEY_SIZE, creq->iv);

	err = crypto_ablkcipher_decrypt(&creq->req);
	if (err)
		return err;

	return poly_init(req);
}

static void chacha_encrypt_done(struct crypto_async_request *areq, int err)
{
	async_done_continue(areq->data, err, poly_genkey);
}

static int chacha_encrypt(struct aead_request *req)
{
	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
	struct chacha_req *creq = &rctx->u.chacha;
	struct scatterlist *src, *dst;
	int err;

	chacha_iv(creq->iv, req, 1);

	sg_init_table(rctx->src, 2);
	src = scatterwalk_ffwd(rctx->src, req->src, req->assoclen);
	dst = src;

	if (req->src != req->dst) {
		sg_init_table(rctx->dst, 2);
		dst = scatterwalk_ffwd(rctx->dst, req->dst, req->assoclen);
	}

	ablkcipher_request_set_callback(&creq->req, aead_request_flags(req),
					chacha_encrypt_done, req);
	ablkcipher_request_set_tfm(&creq->req, ctx->chacha);
	ablkcipher_request_set_crypt(&creq->req, src, dst,
				     req->cryptlen, creq->iv);
	err = crypto_ablkcipher_encrypt(&creq->req);
	if (err)
		return err;

	return poly_genkey(req);
}

static int chachapoly_encrypt(struct aead_request *req)
{
	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);

	rctx->cryptlen = req->cryptlen;

	/* encrypt call chain:
	 * - chacha_encrypt/done()
	 * - poly_genkey/done()
	 * - poly_init/done()
	 * - poly_setkey/done()
	 * - poly_ad/done()
	 * - poly_adpad/done()
	 * - poly_cipher/done()
	 * - poly_cipherpad/done()
	 * - poly_tail/done/continue()
	 * - poly_copy_tag()
	 */
	return chacha_encrypt(req);
}

static int chachapoly_decrypt(struct aead_request *req)
{
	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);

	rctx->cryptlen = req->cryptlen - POLY1305_DIGEST_SIZE;

	/* decrypt call chain:
	 * - poly_genkey/done()
	 * - poly_init/done()
	 * - poly_setkey/done()
	 * - poly_ad/done()
	 * - poly_adpad/done()
	 * - poly_cipher/done()
	 * - poly_cipherpad/done()
	 * - poly_tail/done/continue()
	 * - chacha_decrypt/done()
	 * - poly_verify_tag()
	 */
	return poly_genkey(req);
}

static int chachapoly_setkey(struct crypto_aead *aead, const u8 *key,
			     unsigned int keylen)
{
	struct chachapoly_ctx *ctx = crypto_aead_ctx(aead);
	int err;

	if (keylen != ctx->saltlen + CHACHA20_KEY_SIZE)
		return -EINVAL;

	keylen -= ctx->saltlen;
	memcpy(ctx->salt, key + keylen, ctx->saltlen);

	crypto_ablkcipher_clear_flags(ctx->chacha, CRYPTO_TFM_REQ_MASK);
	crypto_ablkcipher_set_flags(ctx->chacha, crypto_aead_get_flags(aead) &
				    CRYPTO_TFM_REQ_MASK);

	err = crypto_ablkcipher_setkey(ctx->chacha, key, keylen);
	crypto_aead_set_flags(aead, crypto_ablkcipher_get_flags(ctx->chacha) &
			      CRYPTO_TFM_RES_MASK);
	return err;
}

static int chachapoly_setauthsize(struct crypto_aead *tfm,
				  unsigned int authsize)
{
	if (authsize != POLY1305_DIGEST_SIZE)
		return -EINVAL;

	return 0;
}

static int chachapoly_init(struct crypto_aead *tfm)
{
	struct aead_instance *inst = aead_alg_instance(tfm);
	struct chachapoly_instance_ctx *ictx = aead_instance_ctx(inst);
	struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
	struct crypto_ablkcipher *chacha;
	struct crypto_ahash *poly;
	unsigned long align;

	poly = crypto_spawn_ahash(&ictx->poly);
	if (IS_ERR(poly))
		return PTR_ERR(poly);

	chacha = crypto_spawn_skcipher(&ictx->chacha);
	if (IS_ERR(chacha)) {
		crypto_free_ahash(poly);
		return PTR_ERR(chacha);
	}

	ctx->chacha = chacha;
	ctx->poly = poly;
	ctx->saltlen = ictx->saltlen;

	align = crypto_aead_alignmask(tfm);
	align &= ~(crypto_tfm_ctx_alignment() - 1);
	crypto_aead_set_reqsize(
		tfm,
		align + offsetof(struct chachapoly_req_ctx, u) +
		max(offsetof(struct chacha_req, req) +
		    sizeof(struct ablkcipher_request) +
		    crypto_ablkcipher_reqsize(chacha),
		    offsetof(struct poly_req, req) +
		    sizeof(struct ahash_request) +
		    crypto_ahash_reqsize(poly)));

	return 0;
}

static void chachapoly_exit(struct crypto_aead *tfm)
{
	struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);

	crypto_free_ahash(ctx->poly);
	crypto_free_ablkcipher(ctx->chacha);
}

static void chachapoly_free(struct aead_instance *inst)
{
	struct chachapoly_instance_ctx *ctx = aead_instance_ctx(inst);

	crypto_drop_skcipher(&ctx->chacha);
	crypto_drop_ahash(&ctx->poly);
	kfree(inst);
}

static int chachapoly_create(struct crypto_template *tmpl, struct rtattr **tb,
			     const char *name, unsigned int ivsize)
{
	struct crypto_attr_type *algt;
	struct aead_instance *inst;
	struct crypto_alg *chacha;
	struct crypto_alg *poly;
	struct hash_alg_common *poly_hash;
	struct chachapoly_instance_ctx *ctx;
	const char *chacha_name, *poly_name;
	int err;

	if (ivsize > CHACHAPOLY_IV_SIZE)
		return -EINVAL;

	algt = crypto_get_attr_type(tb);
	if (IS_ERR(algt))
		return PTR_ERR(algt);

	if ((algt->type ^ (CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_AEAD_NEW)) &
	    algt->mask)
		return -EINVAL;

	chacha_name = crypto_attr_alg_name(tb[1]);
	if (IS_ERR(chacha_name))
		return PTR_ERR(chacha_name);
	poly_name = crypto_attr_alg_name(tb[2]);
	if (IS_ERR(poly_name))
		return PTR_ERR(poly_name);

	poly = crypto_find_alg(poly_name, &crypto_ahash_type,
			       CRYPTO_ALG_TYPE_HASH,
			       CRYPTO_ALG_TYPE_AHASH_MASK);
	if (IS_ERR(poly))
		return PTR_ERR(poly);

	err = -ENOMEM;
	inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
	if (!inst)
		goto out_put_poly;

	ctx = aead_instance_ctx(inst);
	ctx->saltlen = CHACHAPOLY_IV_SIZE - ivsize;
	poly_hash = __crypto_hash_alg_common(poly);
	err = crypto_init_ahash_spawn(&ctx->poly, poly_hash,
				      aead_crypto_instance(inst));
	if (err)
		goto err_free_inst;

	crypto_set_skcipher_spawn(&ctx->chacha, aead_crypto_instance(inst));
	err = crypto_grab_skcipher(&ctx->chacha, chacha_name, 0,
				   crypto_requires_sync(algt->type,
							algt->mask));
	if (err)
		goto err_drop_poly;

	chacha = crypto_skcipher_spawn_alg(&ctx->chacha);

	err = -EINVAL;
	/* Need 16-byte IV size, including Initial Block Counter value */
	if (chacha->cra_ablkcipher.ivsize != CHACHA20_IV_SIZE)
		goto out_drop_chacha;
	/* Not a stream cipher? */
	if (chacha->cra_blocksize != 1)
		goto out_drop_chacha;

	err = -ENAMETOOLONG;
	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
		     "%s(%s,%s)", name, chacha_name,
		     poly_name) >= CRYPTO_MAX_ALG_NAME)
		goto out_drop_chacha;
	if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
		     "%s(%s,%s)", name, chacha->cra_driver_name,
		     poly->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
		goto out_drop_chacha;

	inst->alg.base.cra_flags = (chacha->cra_flags | poly->cra_flags) &
				   CRYPTO_ALG_ASYNC;
	inst->alg.base.cra_flags |= CRYPTO_ALG_AEAD_NEW;
	inst->alg.base.cra_priority = (chacha->cra_priority +
				       poly->cra_priority) / 2;
	inst->alg.base.cra_blocksize = 1;
	inst->alg.base.cra_alignmask = chacha->cra_alignmask |
				       poly->cra_alignmask;
	inst->alg.base.cra_ctxsize = sizeof(struct chachapoly_ctx) +
				     ctx->saltlen;
	inst->alg.ivsize = ivsize;
	inst->alg.maxauthsize = POLY1305_DIGEST_SIZE;
	inst->alg.init = chachapoly_init;
	inst->alg.exit = chachapoly_exit;
	inst->alg.encrypt = chachapoly_encrypt;
	inst->alg.decrypt = chachapoly_decrypt;
	inst->alg.setkey = chachapoly_setkey;
	inst->alg.setauthsize = chachapoly_setauthsize;

	inst->free = chachapoly_free;

	err = aead_register_instance(tmpl, inst);
	if (err)
		goto out_drop_chacha;

out_put_poly:
	crypto_mod_put(poly);
	return err;

out_drop_chacha:
	crypto_drop_skcipher(&ctx->chacha);
err_drop_poly:
	crypto_drop_ahash(&ctx->poly);
err_free_inst:
	kfree(inst);
	goto out_put_poly;
}

static int rfc7539_create(struct crypto_template *tmpl, struct rtattr **tb)
{
	return chachapoly_create(tmpl, tb, "rfc7539", 12);
}

static int rfc7539esp_create(struct crypto_template *tmpl, struct rtattr **tb)
{
	return chachapoly_create(tmpl, tb, "rfc7539esp", 8);
}

static struct crypto_template rfc7539_tmpl = {
	.name = "rfc7539",
	.create = rfc7539_create,
	.module = THIS_MODULE,
};

static struct crypto_template rfc7539esp_tmpl = {
	.name = "rfc7539esp",
	.create = rfc7539esp_create,
	.module = THIS_MODULE,
};

static int __init chacha20poly1305_module_init(void)
{
	int err;

	err = crypto_register_template(&rfc7539_tmpl);
	if (err)
		return err;

	err = crypto_register_template(&rfc7539esp_tmpl);
	if (err)
		crypto_unregister_template(&rfc7539_tmpl);

	return err;
}

static void __exit chacha20poly1305_module_exit(void)
{
	crypto_unregister_template(&rfc7539esp_tmpl);
	crypto_unregister_template(&rfc7539_tmpl);
}

module_init(chacha20poly1305_module_init);
module_exit(chacha20poly1305_module_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
MODULE_DESCRIPTION("ChaCha20-Poly1305 AEAD");
MODULE_ALIAS_CRYPTO("rfc7539");
MODULE_ALIAS_CRYPTO("rfc7539esp");