xref: /openbmc/linux/crypto/chacha20poly1305.c (revision 293d5b43)
1 /*
2  * ChaCha20-Poly1305 AEAD, RFC7539
3  *
4  * Copyright (C) 2015 Martin Willi
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  */
11 
12 #include <crypto/internal/aead.h>
13 #include <crypto/internal/hash.h>
14 #include <crypto/internal/skcipher.h>
15 #include <crypto/scatterwalk.h>
16 #include <crypto/chacha20.h>
17 #include <crypto/poly1305.h>
18 #include <linux/err.h>
19 #include <linux/init.h>
20 #include <linux/kernel.h>
21 #include <linux/module.h>
22 
23 #include "internal.h"
24 
25 #define CHACHAPOLY_IV_SIZE	12
26 
27 struct chachapoly_instance_ctx {
28 	struct crypto_skcipher_spawn chacha;
29 	struct crypto_ahash_spawn poly;
30 	unsigned int saltlen;
31 };
32 
33 struct chachapoly_ctx {
34 	struct crypto_skcipher *chacha;
35 	struct crypto_ahash *poly;
36 	/* key bytes we use for the ChaCha20 IV */
37 	unsigned int saltlen;
38 	u8 salt[];
39 };
40 
41 struct poly_req {
42 	/* zero byte padding for AD/ciphertext, as needed */
43 	u8 pad[POLY1305_BLOCK_SIZE];
44 	/* tail data with AD/ciphertext lengths */
45 	struct {
46 		__le64 assoclen;
47 		__le64 cryptlen;
48 	} tail;
49 	struct scatterlist src[1];
50 	struct ahash_request req; /* must be last member */
51 };
52 
53 struct chacha_req {
54 	u8 iv[CHACHA20_IV_SIZE];
55 	struct scatterlist src[1];
56 	struct skcipher_request req; /* must be last member */
57 };
58 
59 struct chachapoly_req_ctx {
60 	struct scatterlist src[2];
61 	struct scatterlist dst[2];
62 	/* the key we generate for Poly1305 using Chacha20 */
63 	u8 key[POLY1305_KEY_SIZE];
64 	/* calculated Poly1305 tag */
65 	u8 tag[POLY1305_DIGEST_SIZE];
66 	/* length of data to en/decrypt, without ICV */
67 	unsigned int cryptlen;
68 	/* Actual AD, excluding IV */
69 	unsigned int assoclen;
70 	union {
71 		struct poly_req poly;
72 		struct chacha_req chacha;
73 	} u;
74 };
75 
76 static inline void async_done_continue(struct aead_request *req, int err,
77 				       int (*cont)(struct aead_request *))
78 {
79 	if (!err)
80 		err = cont(req);
81 
82 	if (err != -EINPROGRESS && err != -EBUSY)
83 		aead_request_complete(req, err);
84 }
85 
86 static void chacha_iv(u8 *iv, struct aead_request *req, u32 icb)
87 {
88 	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
89 	__le32 leicb = cpu_to_le32(icb);
90 
91 	memcpy(iv, &leicb, sizeof(leicb));
92 	memcpy(iv + sizeof(leicb), ctx->salt, ctx->saltlen);
93 	memcpy(iv + sizeof(leicb) + ctx->saltlen, req->iv,
94 	       CHACHA20_IV_SIZE - sizeof(leicb) - ctx->saltlen);
95 }
96 
97 static int poly_verify_tag(struct aead_request *req)
98 {
99 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
100 	u8 tag[sizeof(rctx->tag)];
101 
102 	scatterwalk_map_and_copy(tag, req->src,
103 				 req->assoclen + rctx->cryptlen,
104 				 sizeof(tag), 0);
105 	if (crypto_memneq(tag, rctx->tag, sizeof(tag)))
106 		return -EBADMSG;
107 	return 0;
108 }
109 
110 static int poly_copy_tag(struct aead_request *req)
111 {
112 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
113 
114 	scatterwalk_map_and_copy(rctx->tag, req->dst,
115 				 req->assoclen + rctx->cryptlen,
116 				 sizeof(rctx->tag), 1);
117 	return 0;
118 }
119 
120 static void chacha_decrypt_done(struct crypto_async_request *areq, int err)
121 {
122 	async_done_continue(areq->data, err, poly_verify_tag);
123 }
124 
125 static int chacha_decrypt(struct aead_request *req)
126 {
127 	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
128 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
129 	struct chacha_req *creq = &rctx->u.chacha;
130 	struct scatterlist *src, *dst;
131 	int err;
132 
133 	if (rctx->cryptlen == 0)
134 		goto skip;
135 
136 	chacha_iv(creq->iv, req, 1);
137 
138 	sg_init_table(rctx->src, 2);
139 	src = scatterwalk_ffwd(rctx->src, req->src, req->assoclen);
140 	dst = src;
141 
142 	if (req->src != req->dst) {
143 		sg_init_table(rctx->dst, 2);
144 		dst = scatterwalk_ffwd(rctx->dst, req->dst, req->assoclen);
145 	}
146 
147 	skcipher_request_set_callback(&creq->req, aead_request_flags(req),
148 				      chacha_decrypt_done, req);
149 	skcipher_request_set_tfm(&creq->req, ctx->chacha);
150 	skcipher_request_set_crypt(&creq->req, src, dst,
151 				   rctx->cryptlen, creq->iv);
152 	err = crypto_skcipher_decrypt(&creq->req);
153 	if (err)
154 		return err;
155 
156 skip:
157 	return poly_verify_tag(req);
158 }
159 
160 static int poly_tail_continue(struct aead_request *req)
161 {
162 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
163 
164 	if (rctx->cryptlen == req->cryptlen) /* encrypting */
165 		return poly_copy_tag(req);
166 
167 	return chacha_decrypt(req);
168 }
169 
170 static void poly_tail_done(struct crypto_async_request *areq, int err)
171 {
172 	async_done_continue(areq->data, err, poly_tail_continue);
173 }
174 
175 static int poly_tail(struct aead_request *req)
176 {
177 	struct crypto_aead *tfm = crypto_aead_reqtfm(req);
178 	struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
179 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
180 	struct poly_req *preq = &rctx->u.poly;
181 	__le64 len;
182 	int err;
183 
184 	sg_init_table(preq->src, 1);
185 	len = cpu_to_le64(rctx->assoclen);
186 	memcpy(&preq->tail.assoclen, &len, sizeof(len));
187 	len = cpu_to_le64(rctx->cryptlen);
188 	memcpy(&preq->tail.cryptlen, &len, sizeof(len));
189 	sg_set_buf(preq->src, &preq->tail, sizeof(preq->tail));
190 
191 	ahash_request_set_callback(&preq->req, aead_request_flags(req),
192 				   poly_tail_done, req);
193 	ahash_request_set_tfm(&preq->req, ctx->poly);
194 	ahash_request_set_crypt(&preq->req, preq->src,
195 				rctx->tag, sizeof(preq->tail));
196 
197 	err = crypto_ahash_finup(&preq->req);
198 	if (err)
199 		return err;
200 
201 	return poly_tail_continue(req);
202 }
203 
204 static void poly_cipherpad_done(struct crypto_async_request *areq, int err)
205 {
206 	async_done_continue(areq->data, err, poly_tail);
207 }
208 
209 static int poly_cipherpad(struct aead_request *req)
210 {
211 	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
212 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
213 	struct poly_req *preq = &rctx->u.poly;
214 	unsigned int padlen, bs = POLY1305_BLOCK_SIZE;
215 	int err;
216 
217 	padlen = (bs - (rctx->cryptlen % bs)) % bs;
218 	memset(preq->pad, 0, sizeof(preq->pad));
219 	sg_init_table(preq->src, 1);
220 	sg_set_buf(preq->src, &preq->pad, padlen);
221 
222 	ahash_request_set_callback(&preq->req, aead_request_flags(req),
223 				   poly_cipherpad_done, req);
224 	ahash_request_set_tfm(&preq->req, ctx->poly);
225 	ahash_request_set_crypt(&preq->req, preq->src, NULL, padlen);
226 
227 	err = crypto_ahash_update(&preq->req);
228 	if (err)
229 		return err;
230 
231 	return poly_tail(req);
232 }
233 
234 static void poly_cipher_done(struct crypto_async_request *areq, int err)
235 {
236 	async_done_continue(areq->data, err, poly_cipherpad);
237 }
238 
239 static int poly_cipher(struct aead_request *req)
240 {
241 	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
242 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
243 	struct poly_req *preq = &rctx->u.poly;
244 	struct scatterlist *crypt = req->src;
245 	int err;
246 
247 	if (rctx->cryptlen == req->cryptlen) /* encrypting */
248 		crypt = req->dst;
249 
250 	sg_init_table(rctx->src, 2);
251 	crypt = scatterwalk_ffwd(rctx->src, crypt, req->assoclen);
252 
253 	ahash_request_set_callback(&preq->req, aead_request_flags(req),
254 				   poly_cipher_done, req);
255 	ahash_request_set_tfm(&preq->req, ctx->poly);
256 	ahash_request_set_crypt(&preq->req, crypt, NULL, rctx->cryptlen);
257 
258 	err = crypto_ahash_update(&preq->req);
259 	if (err)
260 		return err;
261 
262 	return poly_cipherpad(req);
263 }
264 
265 static void poly_adpad_done(struct crypto_async_request *areq, int err)
266 {
267 	async_done_continue(areq->data, err, poly_cipher);
268 }
269 
270 static int poly_adpad(struct aead_request *req)
271 {
272 	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
273 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
274 	struct poly_req *preq = &rctx->u.poly;
275 	unsigned int padlen, bs = POLY1305_BLOCK_SIZE;
276 	int err;
277 
278 	padlen = (bs - (rctx->assoclen % bs)) % bs;
279 	memset(preq->pad, 0, sizeof(preq->pad));
280 	sg_init_table(preq->src, 1);
281 	sg_set_buf(preq->src, preq->pad, padlen);
282 
283 	ahash_request_set_callback(&preq->req, aead_request_flags(req),
284 				   poly_adpad_done, req);
285 	ahash_request_set_tfm(&preq->req, ctx->poly);
286 	ahash_request_set_crypt(&preq->req, preq->src, NULL, padlen);
287 
288 	err = crypto_ahash_update(&preq->req);
289 	if (err)
290 		return err;
291 
292 	return poly_cipher(req);
293 }
294 
295 static void poly_ad_done(struct crypto_async_request *areq, int err)
296 {
297 	async_done_continue(areq->data, err, poly_adpad);
298 }
299 
300 static int poly_ad(struct aead_request *req)
301 {
302 	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
303 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
304 	struct poly_req *preq = &rctx->u.poly;
305 	int err;
306 
307 	ahash_request_set_callback(&preq->req, aead_request_flags(req),
308 				   poly_ad_done, req);
309 	ahash_request_set_tfm(&preq->req, ctx->poly);
310 	ahash_request_set_crypt(&preq->req, req->src, NULL, rctx->assoclen);
311 
312 	err = crypto_ahash_update(&preq->req);
313 	if (err)
314 		return err;
315 
316 	return poly_adpad(req);
317 }
318 
319 static void poly_setkey_done(struct crypto_async_request *areq, int err)
320 {
321 	async_done_continue(areq->data, err, poly_ad);
322 }
323 
324 static int poly_setkey(struct aead_request *req)
325 {
326 	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
327 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
328 	struct poly_req *preq = &rctx->u.poly;
329 	int err;
330 
331 	sg_init_table(preq->src, 1);
332 	sg_set_buf(preq->src, rctx->key, sizeof(rctx->key));
333 
334 	ahash_request_set_callback(&preq->req, aead_request_flags(req),
335 				   poly_setkey_done, req);
336 	ahash_request_set_tfm(&preq->req, ctx->poly);
337 	ahash_request_set_crypt(&preq->req, preq->src, NULL, sizeof(rctx->key));
338 
339 	err = crypto_ahash_update(&preq->req);
340 	if (err)
341 		return err;
342 
343 	return poly_ad(req);
344 }
345 
346 static void poly_init_done(struct crypto_async_request *areq, int err)
347 {
348 	async_done_continue(areq->data, err, poly_setkey);
349 }
350 
351 static int poly_init(struct aead_request *req)
352 {
353 	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
354 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
355 	struct poly_req *preq = &rctx->u.poly;
356 	int err;
357 
358 	ahash_request_set_callback(&preq->req, aead_request_flags(req),
359 				   poly_init_done, req);
360 	ahash_request_set_tfm(&preq->req, ctx->poly);
361 
362 	err = crypto_ahash_init(&preq->req);
363 	if (err)
364 		return err;
365 
366 	return poly_setkey(req);
367 }
368 
369 static void poly_genkey_done(struct crypto_async_request *areq, int err)
370 {
371 	async_done_continue(areq->data, err, poly_init);
372 }
373 
374 static int poly_genkey(struct aead_request *req)
375 {
376 	struct crypto_aead *tfm = crypto_aead_reqtfm(req);
377 	struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
378 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
379 	struct chacha_req *creq = &rctx->u.chacha;
380 	int err;
381 
382 	rctx->assoclen = req->assoclen;
383 
384 	if (crypto_aead_ivsize(tfm) == 8) {
385 		if (rctx->assoclen < 8)
386 			return -EINVAL;
387 		rctx->assoclen -= 8;
388 	}
389 
390 	sg_init_table(creq->src, 1);
391 	memset(rctx->key, 0, sizeof(rctx->key));
392 	sg_set_buf(creq->src, rctx->key, sizeof(rctx->key));
393 
394 	chacha_iv(creq->iv, req, 0);
395 
396 	skcipher_request_set_callback(&creq->req, aead_request_flags(req),
397 				      poly_genkey_done, req);
398 	skcipher_request_set_tfm(&creq->req, ctx->chacha);
399 	skcipher_request_set_crypt(&creq->req, creq->src, creq->src,
400 				   POLY1305_KEY_SIZE, creq->iv);
401 
402 	err = crypto_skcipher_decrypt(&creq->req);
403 	if (err)
404 		return err;
405 
406 	return poly_init(req);
407 }
408 
409 static void chacha_encrypt_done(struct crypto_async_request *areq, int err)
410 {
411 	async_done_continue(areq->data, err, poly_genkey);
412 }
413 
414 static int chacha_encrypt(struct aead_request *req)
415 {
416 	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
417 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
418 	struct chacha_req *creq = &rctx->u.chacha;
419 	struct scatterlist *src, *dst;
420 	int err;
421 
422 	if (req->cryptlen == 0)
423 		goto skip;
424 
425 	chacha_iv(creq->iv, req, 1);
426 
427 	sg_init_table(rctx->src, 2);
428 	src = scatterwalk_ffwd(rctx->src, req->src, req->assoclen);
429 	dst = src;
430 
431 	if (req->src != req->dst) {
432 		sg_init_table(rctx->dst, 2);
433 		dst = scatterwalk_ffwd(rctx->dst, req->dst, req->assoclen);
434 	}
435 
436 	skcipher_request_set_callback(&creq->req, aead_request_flags(req),
437 				      chacha_encrypt_done, req);
438 	skcipher_request_set_tfm(&creq->req, ctx->chacha);
439 	skcipher_request_set_crypt(&creq->req, src, dst,
440 				   req->cryptlen, creq->iv);
441 	err = crypto_skcipher_encrypt(&creq->req);
442 	if (err)
443 		return err;
444 
445 skip:
446 	return poly_genkey(req);
447 }
448 
449 static int chachapoly_encrypt(struct aead_request *req)
450 {
451 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
452 
453 	rctx->cryptlen = req->cryptlen;
454 
455 	/* encrypt call chain:
456 	 * - chacha_encrypt/done()
457 	 * - poly_genkey/done()
458 	 * - poly_init/done()
459 	 * - poly_setkey/done()
460 	 * - poly_ad/done()
461 	 * - poly_adpad/done()
462 	 * - poly_cipher/done()
463 	 * - poly_cipherpad/done()
464 	 * - poly_tail/done/continue()
465 	 * - poly_copy_tag()
466 	 */
467 	return chacha_encrypt(req);
468 }
469 
470 static int chachapoly_decrypt(struct aead_request *req)
471 {
472 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
473 
474 	rctx->cryptlen = req->cryptlen - POLY1305_DIGEST_SIZE;
475 
476 	/* decrypt call chain:
477 	 * - poly_genkey/done()
478 	 * - poly_init/done()
479 	 * - poly_setkey/done()
480 	 * - poly_ad/done()
481 	 * - poly_adpad/done()
482 	 * - poly_cipher/done()
483 	 * - poly_cipherpad/done()
484 	 * - poly_tail/done/continue()
485 	 * - chacha_decrypt/done()
486 	 * - poly_verify_tag()
487 	 */
488 	return poly_genkey(req);
489 }
490 
491 static int chachapoly_setkey(struct crypto_aead *aead, const u8 *key,
492 			     unsigned int keylen)
493 {
494 	struct chachapoly_ctx *ctx = crypto_aead_ctx(aead);
495 	int err;
496 
497 	if (keylen != ctx->saltlen + CHACHA20_KEY_SIZE)
498 		return -EINVAL;
499 
500 	keylen -= ctx->saltlen;
501 	memcpy(ctx->salt, key + keylen, ctx->saltlen);
502 
503 	crypto_skcipher_clear_flags(ctx->chacha, CRYPTO_TFM_REQ_MASK);
504 	crypto_skcipher_set_flags(ctx->chacha, crypto_aead_get_flags(aead) &
505 					       CRYPTO_TFM_REQ_MASK);
506 
507 	err = crypto_skcipher_setkey(ctx->chacha, key, keylen);
508 	crypto_aead_set_flags(aead, crypto_skcipher_get_flags(ctx->chacha) &
509 				    CRYPTO_TFM_RES_MASK);
510 	return err;
511 }
512 
513 static int chachapoly_setauthsize(struct crypto_aead *tfm,
514 				  unsigned int authsize)
515 {
516 	if (authsize != POLY1305_DIGEST_SIZE)
517 		return -EINVAL;
518 
519 	return 0;
520 }
521 
522 static int chachapoly_init(struct crypto_aead *tfm)
523 {
524 	struct aead_instance *inst = aead_alg_instance(tfm);
525 	struct chachapoly_instance_ctx *ictx = aead_instance_ctx(inst);
526 	struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
527 	struct crypto_skcipher *chacha;
528 	struct crypto_ahash *poly;
529 	unsigned long align;
530 
531 	poly = crypto_spawn_ahash(&ictx->poly);
532 	if (IS_ERR(poly))
533 		return PTR_ERR(poly);
534 
535 	chacha = crypto_spawn_skcipher2(&ictx->chacha);
536 	if (IS_ERR(chacha)) {
537 		crypto_free_ahash(poly);
538 		return PTR_ERR(chacha);
539 	}
540 
541 	ctx->chacha = chacha;
542 	ctx->poly = poly;
543 	ctx->saltlen = ictx->saltlen;
544 
545 	align = crypto_aead_alignmask(tfm);
546 	align &= ~(crypto_tfm_ctx_alignment() - 1);
547 	crypto_aead_set_reqsize(
548 		tfm,
549 		align + offsetof(struct chachapoly_req_ctx, u) +
550 		max(offsetof(struct chacha_req, req) +
551 		    sizeof(struct skcipher_request) +
552 		    crypto_skcipher_reqsize(chacha),
553 		    offsetof(struct poly_req, req) +
554 		    sizeof(struct ahash_request) +
555 		    crypto_ahash_reqsize(poly)));
556 
557 	return 0;
558 }
559 
560 static void chachapoly_exit(struct crypto_aead *tfm)
561 {
562 	struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
563 
564 	crypto_free_ahash(ctx->poly);
565 	crypto_free_skcipher(ctx->chacha);
566 }
567 
568 static void chachapoly_free(struct aead_instance *inst)
569 {
570 	struct chachapoly_instance_ctx *ctx = aead_instance_ctx(inst);
571 
572 	crypto_drop_skcipher(&ctx->chacha);
573 	crypto_drop_ahash(&ctx->poly);
574 	kfree(inst);
575 }
576 
577 static int chachapoly_create(struct crypto_template *tmpl, struct rtattr **tb,
578 			     const char *name, unsigned int ivsize)
579 {
580 	struct crypto_attr_type *algt;
581 	struct aead_instance *inst;
582 	struct skcipher_alg *chacha;
583 	struct crypto_alg *poly;
584 	struct hash_alg_common *poly_hash;
585 	struct chachapoly_instance_ctx *ctx;
586 	const char *chacha_name, *poly_name;
587 	int err;
588 
589 	if (ivsize > CHACHAPOLY_IV_SIZE)
590 		return -EINVAL;
591 
592 	algt = crypto_get_attr_type(tb);
593 	if (IS_ERR(algt))
594 		return PTR_ERR(algt);
595 
596 	if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
597 		return -EINVAL;
598 
599 	chacha_name = crypto_attr_alg_name(tb[1]);
600 	if (IS_ERR(chacha_name))
601 		return PTR_ERR(chacha_name);
602 	poly_name = crypto_attr_alg_name(tb[2]);
603 	if (IS_ERR(poly_name))
604 		return PTR_ERR(poly_name);
605 
606 	poly = crypto_find_alg(poly_name, &crypto_ahash_type,
607 			       CRYPTO_ALG_TYPE_HASH,
608 			       CRYPTO_ALG_TYPE_AHASH_MASK |
609 			       crypto_requires_sync(algt->type,
610 						    algt->mask));
611 	if (IS_ERR(poly))
612 		return PTR_ERR(poly);
613 
614 	err = -ENOMEM;
615 	inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
616 	if (!inst)
617 		goto out_put_poly;
618 
619 	ctx = aead_instance_ctx(inst);
620 	ctx->saltlen = CHACHAPOLY_IV_SIZE - ivsize;
621 	poly_hash = __crypto_hash_alg_common(poly);
622 	err = crypto_init_ahash_spawn(&ctx->poly, poly_hash,
623 				      aead_crypto_instance(inst));
624 	if (err)
625 		goto err_free_inst;
626 
627 	crypto_set_skcipher_spawn(&ctx->chacha, aead_crypto_instance(inst));
628 	err = crypto_grab_skcipher2(&ctx->chacha, chacha_name, 0,
629 				    crypto_requires_sync(algt->type,
630 							 algt->mask));
631 	if (err)
632 		goto err_drop_poly;
633 
634 	chacha = crypto_spawn_skcipher_alg(&ctx->chacha);
635 
636 	err = -EINVAL;
637 	/* Need 16-byte IV size, including Initial Block Counter value */
638 	if (crypto_skcipher_alg_ivsize(chacha) != CHACHA20_IV_SIZE)
639 		goto out_drop_chacha;
640 	/* Not a stream cipher? */
641 	if (chacha->base.cra_blocksize != 1)
642 		goto out_drop_chacha;
643 
644 	err = -ENAMETOOLONG;
645 	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
646 		     "%s(%s,%s)", name, chacha_name,
647 		     poly_name) >= CRYPTO_MAX_ALG_NAME)
648 		goto out_drop_chacha;
649 	if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
650 		     "%s(%s,%s)", name, chacha->base.cra_driver_name,
651 		     poly->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
652 		goto out_drop_chacha;
653 
654 	inst->alg.base.cra_flags = (chacha->base.cra_flags | poly->cra_flags) &
655 				   CRYPTO_ALG_ASYNC;
656 	inst->alg.base.cra_priority = (chacha->base.cra_priority +
657 				       poly->cra_priority) / 2;
658 	inst->alg.base.cra_blocksize = 1;
659 	inst->alg.base.cra_alignmask = chacha->base.cra_alignmask |
660 				       poly->cra_alignmask;
661 	inst->alg.base.cra_ctxsize = sizeof(struct chachapoly_ctx) +
662 				     ctx->saltlen;
663 	inst->alg.ivsize = ivsize;
664 	inst->alg.chunksize = crypto_skcipher_alg_chunksize(chacha);
665 	inst->alg.maxauthsize = POLY1305_DIGEST_SIZE;
666 	inst->alg.init = chachapoly_init;
667 	inst->alg.exit = chachapoly_exit;
668 	inst->alg.encrypt = chachapoly_encrypt;
669 	inst->alg.decrypt = chachapoly_decrypt;
670 	inst->alg.setkey = chachapoly_setkey;
671 	inst->alg.setauthsize = chachapoly_setauthsize;
672 
673 	inst->free = chachapoly_free;
674 
675 	err = aead_register_instance(tmpl, inst);
676 	if (err)
677 		goto out_drop_chacha;
678 
679 out_put_poly:
680 	crypto_mod_put(poly);
681 	return err;
682 
683 out_drop_chacha:
684 	crypto_drop_skcipher(&ctx->chacha);
685 err_drop_poly:
686 	crypto_drop_ahash(&ctx->poly);
687 err_free_inst:
688 	kfree(inst);
689 	goto out_put_poly;
690 }
691 
692 static int rfc7539_create(struct crypto_template *tmpl, struct rtattr **tb)
693 {
694 	return chachapoly_create(tmpl, tb, "rfc7539", 12);
695 }
696 
697 static int rfc7539esp_create(struct crypto_template *tmpl, struct rtattr **tb)
698 {
699 	return chachapoly_create(tmpl, tb, "rfc7539esp", 8);
700 }
701 
702 static struct crypto_template rfc7539_tmpl = {
703 	.name = "rfc7539",
704 	.create = rfc7539_create,
705 	.module = THIS_MODULE,
706 };
707 
708 static struct crypto_template rfc7539esp_tmpl = {
709 	.name = "rfc7539esp",
710 	.create = rfc7539esp_create,
711 	.module = THIS_MODULE,
712 };
713 
714 static int __init chacha20poly1305_module_init(void)
715 {
716 	int err;
717 
718 	err = crypto_register_template(&rfc7539_tmpl);
719 	if (err)
720 		return err;
721 
722 	err = crypto_register_template(&rfc7539esp_tmpl);
723 	if (err)
724 		crypto_unregister_template(&rfc7539_tmpl);
725 
726 	return err;
727 }
728 
729 static void __exit chacha20poly1305_module_exit(void)
730 {
731 	crypto_unregister_template(&rfc7539esp_tmpl);
732 	crypto_unregister_template(&rfc7539_tmpl);
733 }
734 
735 module_init(chacha20poly1305_module_init);
736 module_exit(chacha20poly1305_module_exit);
737 
738 MODULE_LICENSE("GPL");
739 MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
740 MODULE_DESCRIPTION("ChaCha20-Poly1305 AEAD");
741 MODULE_ALIAS_CRYPTO("rfc7539");
742 MODULE_ALIAS_CRYPTO("rfc7539esp");
743