xref: /openbmc/linux/crypto/chacha20poly1305.c (revision 4419617e)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * ChaCha20-Poly1305 AEAD, RFC7539
4  *
5  * Copyright (C) 2015 Martin Willi
6  */
7 
8 #include <crypto/internal/aead.h>
9 #include <crypto/internal/hash.h>
10 #include <crypto/internal/skcipher.h>
11 #include <crypto/scatterwalk.h>
12 #include <crypto/chacha.h>
13 #include <crypto/poly1305.h>
14 #include <linux/err.h>
15 #include <linux/init.h>
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 
19 #include "internal.h"
20 
21 struct chachapoly_instance_ctx {
22 	struct crypto_skcipher_spawn chacha;
23 	struct crypto_ahash_spawn poly;
24 	unsigned int saltlen;
25 };
26 
27 struct chachapoly_ctx {
28 	struct crypto_skcipher *chacha;
29 	struct crypto_ahash *poly;
30 	/* key bytes we use for the ChaCha20 IV */
31 	unsigned int saltlen;
32 	u8 salt[];
33 };
34 
35 struct poly_req {
36 	/* zero byte padding for AD/ciphertext, as needed */
37 	u8 pad[POLY1305_BLOCK_SIZE];
38 	/* tail data with AD/ciphertext lengths */
39 	struct {
40 		__le64 assoclen;
41 		__le64 cryptlen;
42 	} tail;
43 	struct scatterlist src[1];
44 	struct ahash_request req; /* must be last member */
45 };
46 
47 struct chacha_req {
48 	u8 iv[CHACHA_IV_SIZE];
49 	struct scatterlist src[1];
50 	struct skcipher_request req; /* must be last member */
51 };
52 
53 struct chachapoly_req_ctx {
54 	struct scatterlist src[2];
55 	struct scatterlist dst[2];
56 	/* the key we generate for Poly1305 using Chacha20 */
57 	u8 key[POLY1305_KEY_SIZE];
58 	/* calculated Poly1305 tag */
59 	u8 tag[POLY1305_DIGEST_SIZE];
60 	/* length of data to en/decrypt, without ICV */
61 	unsigned int cryptlen;
62 	/* Actual AD, excluding IV */
63 	unsigned int assoclen;
64 	union {
65 		struct poly_req poly;
66 		struct chacha_req chacha;
67 	} u;
68 };
69 
70 static inline void async_done_continue(struct aead_request *req, int err,
71 				       int (*cont)(struct aead_request *))
72 {
73 	if (!err)
74 		err = cont(req);
75 
76 	if (err != -EINPROGRESS && err != -EBUSY)
77 		aead_request_complete(req, err);
78 }
79 
80 static void chacha_iv(u8 *iv, struct aead_request *req, u32 icb)
81 {
82 	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
83 	__le32 leicb = cpu_to_le32(icb);
84 
85 	memcpy(iv, &leicb, sizeof(leicb));
86 	memcpy(iv + sizeof(leicb), ctx->salt, ctx->saltlen);
87 	memcpy(iv + sizeof(leicb) + ctx->saltlen, req->iv,
88 	       CHACHA_IV_SIZE - sizeof(leicb) - ctx->saltlen);
89 }
90 
91 static int poly_verify_tag(struct aead_request *req)
92 {
93 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
94 	u8 tag[sizeof(rctx->tag)];
95 
96 	scatterwalk_map_and_copy(tag, req->src,
97 				 req->assoclen + rctx->cryptlen,
98 				 sizeof(tag), 0);
99 	if (crypto_memneq(tag, rctx->tag, sizeof(tag)))
100 		return -EBADMSG;
101 	return 0;
102 }
103 
104 static int poly_copy_tag(struct aead_request *req)
105 {
106 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
107 
108 	scatterwalk_map_and_copy(rctx->tag, req->dst,
109 				 req->assoclen + rctx->cryptlen,
110 				 sizeof(rctx->tag), 1);
111 	return 0;
112 }
113 
114 static void chacha_decrypt_done(struct crypto_async_request *areq, int err)
115 {
116 	async_done_continue(areq->data, err, poly_verify_tag);
117 }
118 
119 static int chacha_decrypt(struct aead_request *req)
120 {
121 	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
122 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
123 	struct chacha_req *creq = &rctx->u.chacha;
124 	struct scatterlist *src, *dst;
125 	int err;
126 
127 	if (rctx->cryptlen == 0)
128 		goto skip;
129 
130 	chacha_iv(creq->iv, req, 1);
131 
132 	sg_init_table(rctx->src, 2);
133 	src = scatterwalk_ffwd(rctx->src, req->src, req->assoclen);
134 	dst = src;
135 
136 	if (req->src != req->dst) {
137 		sg_init_table(rctx->dst, 2);
138 		dst = scatterwalk_ffwd(rctx->dst, req->dst, req->assoclen);
139 	}
140 
141 	skcipher_request_set_callback(&creq->req, aead_request_flags(req),
142 				      chacha_decrypt_done, req);
143 	skcipher_request_set_tfm(&creq->req, ctx->chacha);
144 	skcipher_request_set_crypt(&creq->req, src, dst,
145 				   rctx->cryptlen, creq->iv);
146 	err = crypto_skcipher_decrypt(&creq->req);
147 	if (err)
148 		return err;
149 
150 skip:
151 	return poly_verify_tag(req);
152 }
153 
154 static int poly_tail_continue(struct aead_request *req)
155 {
156 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
157 
158 	if (rctx->cryptlen == req->cryptlen) /* encrypting */
159 		return poly_copy_tag(req);
160 
161 	return chacha_decrypt(req);
162 }
163 
164 static void poly_tail_done(struct crypto_async_request *areq, int err)
165 {
166 	async_done_continue(areq->data, err, poly_tail_continue);
167 }
168 
169 static int poly_tail(struct aead_request *req)
170 {
171 	struct crypto_aead *tfm = crypto_aead_reqtfm(req);
172 	struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
173 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
174 	struct poly_req *preq = &rctx->u.poly;
175 	__le64 len;
176 	int err;
177 
178 	sg_init_table(preq->src, 1);
179 	len = cpu_to_le64(rctx->assoclen);
180 	memcpy(&preq->tail.assoclen, &len, sizeof(len));
181 	len = cpu_to_le64(rctx->cryptlen);
182 	memcpy(&preq->tail.cryptlen, &len, sizeof(len));
183 	sg_set_buf(preq->src, &preq->tail, sizeof(preq->tail));
184 
185 	ahash_request_set_callback(&preq->req, aead_request_flags(req),
186 				   poly_tail_done, req);
187 	ahash_request_set_tfm(&preq->req, ctx->poly);
188 	ahash_request_set_crypt(&preq->req, preq->src,
189 				rctx->tag, sizeof(preq->tail));
190 
191 	err = crypto_ahash_finup(&preq->req);
192 	if (err)
193 		return err;
194 
195 	return poly_tail_continue(req);
196 }
197 
198 static void poly_cipherpad_done(struct crypto_async_request *areq, int err)
199 {
200 	async_done_continue(areq->data, err, poly_tail);
201 }
202 
203 static int poly_cipherpad(struct aead_request *req)
204 {
205 	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
206 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
207 	struct poly_req *preq = &rctx->u.poly;
208 	unsigned int padlen, bs = POLY1305_BLOCK_SIZE;
209 	int err;
210 
211 	padlen = (bs - (rctx->cryptlen % bs)) % bs;
212 	memset(preq->pad, 0, sizeof(preq->pad));
213 	sg_init_table(preq->src, 1);
214 	sg_set_buf(preq->src, &preq->pad, padlen);
215 
216 	ahash_request_set_callback(&preq->req, aead_request_flags(req),
217 				   poly_cipherpad_done, req);
218 	ahash_request_set_tfm(&preq->req, ctx->poly);
219 	ahash_request_set_crypt(&preq->req, preq->src, NULL, padlen);
220 
221 	err = crypto_ahash_update(&preq->req);
222 	if (err)
223 		return err;
224 
225 	return poly_tail(req);
226 }
227 
228 static void poly_cipher_done(struct crypto_async_request *areq, int err)
229 {
230 	async_done_continue(areq->data, err, poly_cipherpad);
231 }
232 
233 static int poly_cipher(struct aead_request *req)
234 {
235 	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
236 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
237 	struct poly_req *preq = &rctx->u.poly;
238 	struct scatterlist *crypt = req->src;
239 	int err;
240 
241 	if (rctx->cryptlen == req->cryptlen) /* encrypting */
242 		crypt = req->dst;
243 
244 	sg_init_table(rctx->src, 2);
245 	crypt = scatterwalk_ffwd(rctx->src, crypt, req->assoclen);
246 
247 	ahash_request_set_callback(&preq->req, aead_request_flags(req),
248 				   poly_cipher_done, req);
249 	ahash_request_set_tfm(&preq->req, ctx->poly);
250 	ahash_request_set_crypt(&preq->req, crypt, NULL, rctx->cryptlen);
251 
252 	err = crypto_ahash_update(&preq->req);
253 	if (err)
254 		return err;
255 
256 	return poly_cipherpad(req);
257 }
258 
259 static void poly_adpad_done(struct crypto_async_request *areq, int err)
260 {
261 	async_done_continue(areq->data, err, poly_cipher);
262 }
263 
264 static int poly_adpad(struct aead_request *req)
265 {
266 	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
267 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
268 	struct poly_req *preq = &rctx->u.poly;
269 	unsigned int padlen, bs = POLY1305_BLOCK_SIZE;
270 	int err;
271 
272 	padlen = (bs - (rctx->assoclen % bs)) % bs;
273 	memset(preq->pad, 0, sizeof(preq->pad));
274 	sg_init_table(preq->src, 1);
275 	sg_set_buf(preq->src, preq->pad, padlen);
276 
277 	ahash_request_set_callback(&preq->req, aead_request_flags(req),
278 				   poly_adpad_done, req);
279 	ahash_request_set_tfm(&preq->req, ctx->poly);
280 	ahash_request_set_crypt(&preq->req, preq->src, NULL, padlen);
281 
282 	err = crypto_ahash_update(&preq->req);
283 	if (err)
284 		return err;
285 
286 	return poly_cipher(req);
287 }
288 
289 static void poly_ad_done(struct crypto_async_request *areq, int err)
290 {
291 	async_done_continue(areq->data, err, poly_adpad);
292 }
293 
294 static int poly_ad(struct aead_request *req)
295 {
296 	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
297 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
298 	struct poly_req *preq = &rctx->u.poly;
299 	int err;
300 
301 	ahash_request_set_callback(&preq->req, aead_request_flags(req),
302 				   poly_ad_done, req);
303 	ahash_request_set_tfm(&preq->req, ctx->poly);
304 	ahash_request_set_crypt(&preq->req, req->src, NULL, rctx->assoclen);
305 
306 	err = crypto_ahash_update(&preq->req);
307 	if (err)
308 		return err;
309 
310 	return poly_adpad(req);
311 }
312 
313 static void poly_setkey_done(struct crypto_async_request *areq, int err)
314 {
315 	async_done_continue(areq->data, err, poly_ad);
316 }
317 
318 static int poly_setkey(struct aead_request *req)
319 {
320 	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
321 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
322 	struct poly_req *preq = &rctx->u.poly;
323 	int err;
324 
325 	sg_init_table(preq->src, 1);
326 	sg_set_buf(preq->src, rctx->key, sizeof(rctx->key));
327 
328 	ahash_request_set_callback(&preq->req, aead_request_flags(req),
329 				   poly_setkey_done, req);
330 	ahash_request_set_tfm(&preq->req, ctx->poly);
331 	ahash_request_set_crypt(&preq->req, preq->src, NULL, sizeof(rctx->key));
332 
333 	err = crypto_ahash_update(&preq->req);
334 	if (err)
335 		return err;
336 
337 	return poly_ad(req);
338 }
339 
340 static void poly_init_done(struct crypto_async_request *areq, int err)
341 {
342 	async_done_continue(areq->data, err, poly_setkey);
343 }
344 
345 static int poly_init(struct aead_request *req)
346 {
347 	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
348 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
349 	struct poly_req *preq = &rctx->u.poly;
350 	int err;
351 
352 	ahash_request_set_callback(&preq->req, aead_request_flags(req),
353 				   poly_init_done, req);
354 	ahash_request_set_tfm(&preq->req, ctx->poly);
355 
356 	err = crypto_ahash_init(&preq->req);
357 	if (err)
358 		return err;
359 
360 	return poly_setkey(req);
361 }
362 
363 static void poly_genkey_done(struct crypto_async_request *areq, int err)
364 {
365 	async_done_continue(areq->data, err, poly_init);
366 }
367 
368 static int poly_genkey(struct aead_request *req)
369 {
370 	struct crypto_aead *tfm = crypto_aead_reqtfm(req);
371 	struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
372 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
373 	struct chacha_req *creq = &rctx->u.chacha;
374 	int err;
375 
376 	rctx->assoclen = req->assoclen;
377 
378 	if (crypto_aead_ivsize(tfm) == 8) {
379 		if (rctx->assoclen < 8)
380 			return -EINVAL;
381 		rctx->assoclen -= 8;
382 	}
383 
384 	sg_init_table(creq->src, 1);
385 	memset(rctx->key, 0, sizeof(rctx->key));
386 	sg_set_buf(creq->src, rctx->key, sizeof(rctx->key));
387 
388 	chacha_iv(creq->iv, req, 0);
389 
390 	skcipher_request_set_callback(&creq->req, aead_request_flags(req),
391 				      poly_genkey_done, req);
392 	skcipher_request_set_tfm(&creq->req, ctx->chacha);
393 	skcipher_request_set_crypt(&creq->req, creq->src, creq->src,
394 				   POLY1305_KEY_SIZE, creq->iv);
395 
396 	err = crypto_skcipher_decrypt(&creq->req);
397 	if (err)
398 		return err;
399 
400 	return poly_init(req);
401 }
402 
403 static void chacha_encrypt_done(struct crypto_async_request *areq, int err)
404 {
405 	async_done_continue(areq->data, err, poly_genkey);
406 }
407 
408 static int chacha_encrypt(struct aead_request *req)
409 {
410 	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
411 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
412 	struct chacha_req *creq = &rctx->u.chacha;
413 	struct scatterlist *src, *dst;
414 	int err;
415 
416 	if (req->cryptlen == 0)
417 		goto skip;
418 
419 	chacha_iv(creq->iv, req, 1);
420 
421 	sg_init_table(rctx->src, 2);
422 	src = scatterwalk_ffwd(rctx->src, req->src, req->assoclen);
423 	dst = src;
424 
425 	if (req->src != req->dst) {
426 		sg_init_table(rctx->dst, 2);
427 		dst = scatterwalk_ffwd(rctx->dst, req->dst, req->assoclen);
428 	}
429 
430 	skcipher_request_set_callback(&creq->req, aead_request_flags(req),
431 				      chacha_encrypt_done, req);
432 	skcipher_request_set_tfm(&creq->req, ctx->chacha);
433 	skcipher_request_set_crypt(&creq->req, src, dst,
434 				   req->cryptlen, creq->iv);
435 	err = crypto_skcipher_encrypt(&creq->req);
436 	if (err)
437 		return err;
438 
439 skip:
440 	return poly_genkey(req);
441 }
442 
443 static int chachapoly_encrypt(struct aead_request *req)
444 {
445 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
446 
447 	rctx->cryptlen = req->cryptlen;
448 
449 	/* encrypt call chain:
450 	 * - chacha_encrypt/done()
451 	 * - poly_genkey/done()
452 	 * - poly_init/done()
453 	 * - poly_setkey/done()
454 	 * - poly_ad/done()
455 	 * - poly_adpad/done()
456 	 * - poly_cipher/done()
457 	 * - poly_cipherpad/done()
458 	 * - poly_tail/done/continue()
459 	 * - poly_copy_tag()
460 	 */
461 	return chacha_encrypt(req);
462 }
463 
464 static int chachapoly_decrypt(struct aead_request *req)
465 {
466 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
467 
468 	rctx->cryptlen = req->cryptlen - POLY1305_DIGEST_SIZE;
469 
470 	/* decrypt call chain:
471 	 * - poly_genkey/done()
472 	 * - poly_init/done()
473 	 * - poly_setkey/done()
474 	 * - poly_ad/done()
475 	 * - poly_adpad/done()
476 	 * - poly_cipher/done()
477 	 * - poly_cipherpad/done()
478 	 * - poly_tail/done/continue()
479 	 * - chacha_decrypt/done()
480 	 * - poly_verify_tag()
481 	 */
482 	return poly_genkey(req);
483 }
484 
485 static int chachapoly_setkey(struct crypto_aead *aead, const u8 *key,
486 			     unsigned int keylen)
487 {
488 	struct chachapoly_ctx *ctx = crypto_aead_ctx(aead);
489 	int err;
490 
491 	if (keylen != ctx->saltlen + CHACHA_KEY_SIZE)
492 		return -EINVAL;
493 
494 	keylen -= ctx->saltlen;
495 	memcpy(ctx->salt, key + keylen, ctx->saltlen);
496 
497 	crypto_skcipher_clear_flags(ctx->chacha, CRYPTO_TFM_REQ_MASK);
498 	crypto_skcipher_set_flags(ctx->chacha, crypto_aead_get_flags(aead) &
499 					       CRYPTO_TFM_REQ_MASK);
500 
501 	err = crypto_skcipher_setkey(ctx->chacha, key, keylen);
502 	crypto_aead_set_flags(aead, crypto_skcipher_get_flags(ctx->chacha) &
503 				    CRYPTO_TFM_RES_MASK);
504 	return err;
505 }
506 
507 static int chachapoly_setauthsize(struct crypto_aead *tfm,
508 				  unsigned int authsize)
509 {
510 	if (authsize != POLY1305_DIGEST_SIZE)
511 		return -EINVAL;
512 
513 	return 0;
514 }
515 
516 static int chachapoly_init(struct crypto_aead *tfm)
517 {
518 	struct aead_instance *inst = aead_alg_instance(tfm);
519 	struct chachapoly_instance_ctx *ictx = aead_instance_ctx(inst);
520 	struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
521 	struct crypto_skcipher *chacha;
522 	struct crypto_ahash *poly;
523 	unsigned long align;
524 
525 	poly = crypto_spawn_ahash(&ictx->poly);
526 	if (IS_ERR(poly))
527 		return PTR_ERR(poly);
528 
529 	chacha = crypto_spawn_skcipher(&ictx->chacha);
530 	if (IS_ERR(chacha)) {
531 		crypto_free_ahash(poly);
532 		return PTR_ERR(chacha);
533 	}
534 
535 	ctx->chacha = chacha;
536 	ctx->poly = poly;
537 	ctx->saltlen = ictx->saltlen;
538 
539 	align = crypto_aead_alignmask(tfm);
540 	align &= ~(crypto_tfm_ctx_alignment() - 1);
541 	crypto_aead_set_reqsize(
542 		tfm,
543 		align + offsetof(struct chachapoly_req_ctx, u) +
544 		max(offsetof(struct chacha_req, req) +
545 		    sizeof(struct skcipher_request) +
546 		    crypto_skcipher_reqsize(chacha),
547 		    offsetof(struct poly_req, req) +
548 		    sizeof(struct ahash_request) +
549 		    crypto_ahash_reqsize(poly)));
550 
551 	return 0;
552 }
553 
554 static void chachapoly_exit(struct crypto_aead *tfm)
555 {
556 	struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
557 
558 	crypto_free_ahash(ctx->poly);
559 	crypto_free_skcipher(ctx->chacha);
560 }
561 
562 static void chachapoly_free(struct aead_instance *inst)
563 {
564 	struct chachapoly_instance_ctx *ctx = aead_instance_ctx(inst);
565 
566 	crypto_drop_skcipher(&ctx->chacha);
567 	crypto_drop_ahash(&ctx->poly);
568 	kfree(inst);
569 }
570 
571 static int chachapoly_create(struct crypto_template *tmpl, struct rtattr **tb,
572 			     const char *name, unsigned int ivsize)
573 {
574 	struct crypto_attr_type *algt;
575 	struct aead_instance *inst;
576 	struct skcipher_alg *chacha;
577 	struct crypto_alg *poly;
578 	struct hash_alg_common *poly_hash;
579 	struct chachapoly_instance_ctx *ctx;
580 	const char *chacha_name, *poly_name;
581 	int err;
582 
583 	if (ivsize > CHACHAPOLY_IV_SIZE)
584 		return -EINVAL;
585 
586 	algt = crypto_get_attr_type(tb);
587 	if (IS_ERR(algt))
588 		return PTR_ERR(algt);
589 
590 	if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
591 		return -EINVAL;
592 
593 	chacha_name = crypto_attr_alg_name(tb[1]);
594 	if (IS_ERR(chacha_name))
595 		return PTR_ERR(chacha_name);
596 	poly_name = crypto_attr_alg_name(tb[2]);
597 	if (IS_ERR(poly_name))
598 		return PTR_ERR(poly_name);
599 
600 	poly = crypto_find_alg(poly_name, &crypto_ahash_type,
601 			       CRYPTO_ALG_TYPE_HASH,
602 			       CRYPTO_ALG_TYPE_AHASH_MASK |
603 			       crypto_requires_sync(algt->type,
604 						    algt->mask));
605 	if (IS_ERR(poly))
606 		return PTR_ERR(poly);
607 	poly_hash = __crypto_hash_alg_common(poly);
608 
609 	err = -EINVAL;
610 	if (poly_hash->digestsize != POLY1305_DIGEST_SIZE)
611 		goto out_put_poly;
612 
613 	err = -ENOMEM;
614 	inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
615 	if (!inst)
616 		goto out_put_poly;
617 
618 	ctx = aead_instance_ctx(inst);
619 	ctx->saltlen = CHACHAPOLY_IV_SIZE - ivsize;
620 	err = crypto_init_ahash_spawn(&ctx->poly, poly_hash,
621 				      aead_crypto_instance(inst));
622 	if (err)
623 		goto err_free_inst;
624 
625 	crypto_set_skcipher_spawn(&ctx->chacha, aead_crypto_instance(inst));
626 	err = crypto_grab_skcipher(&ctx->chacha, chacha_name, 0,
627 				   crypto_requires_sync(algt->type,
628 							algt->mask));
629 	if (err)
630 		goto err_drop_poly;
631 
632 	chacha = crypto_spawn_skcipher_alg(&ctx->chacha);
633 
634 	err = -EINVAL;
635 	/* Need 16-byte IV size, including Initial Block Counter value */
636 	if (crypto_skcipher_alg_ivsize(chacha) != CHACHA_IV_SIZE)
637 		goto out_drop_chacha;
638 	/* Not a stream cipher? */
639 	if (chacha->base.cra_blocksize != 1)
640 		goto out_drop_chacha;
641 
642 	err = -ENAMETOOLONG;
643 	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
644 		     "%s(%s,%s)", name, chacha->base.cra_name,
645 		     poly->cra_name) >= CRYPTO_MAX_ALG_NAME)
646 		goto out_drop_chacha;
647 	if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
648 		     "%s(%s,%s)", name, chacha->base.cra_driver_name,
649 		     poly->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
650 		goto out_drop_chacha;
651 
652 	inst->alg.base.cra_flags = (chacha->base.cra_flags | poly->cra_flags) &
653 				   CRYPTO_ALG_ASYNC;
654 	inst->alg.base.cra_priority = (chacha->base.cra_priority +
655 				       poly->cra_priority) / 2;
656 	inst->alg.base.cra_blocksize = 1;
657 	inst->alg.base.cra_alignmask = chacha->base.cra_alignmask |
658 				       poly->cra_alignmask;
659 	inst->alg.base.cra_ctxsize = sizeof(struct chachapoly_ctx) +
660 				     ctx->saltlen;
661 	inst->alg.ivsize = ivsize;
662 	inst->alg.chunksize = crypto_skcipher_alg_chunksize(chacha);
663 	inst->alg.maxauthsize = POLY1305_DIGEST_SIZE;
664 	inst->alg.init = chachapoly_init;
665 	inst->alg.exit = chachapoly_exit;
666 	inst->alg.encrypt = chachapoly_encrypt;
667 	inst->alg.decrypt = chachapoly_decrypt;
668 	inst->alg.setkey = chachapoly_setkey;
669 	inst->alg.setauthsize = chachapoly_setauthsize;
670 
671 	inst->free = chachapoly_free;
672 
673 	err = aead_register_instance(tmpl, inst);
674 	if (err)
675 		goto out_drop_chacha;
676 
677 out_put_poly:
678 	crypto_mod_put(poly);
679 	return err;
680 
681 out_drop_chacha:
682 	crypto_drop_skcipher(&ctx->chacha);
683 err_drop_poly:
684 	crypto_drop_ahash(&ctx->poly);
685 err_free_inst:
686 	kfree(inst);
687 	goto out_put_poly;
688 }
689 
690 static int rfc7539_create(struct crypto_template *tmpl, struct rtattr **tb)
691 {
692 	return chachapoly_create(tmpl, tb, "rfc7539", 12);
693 }
694 
695 static int rfc7539esp_create(struct crypto_template *tmpl, struct rtattr **tb)
696 {
697 	return chachapoly_create(tmpl, tb, "rfc7539esp", 8);
698 }
699 
700 static struct crypto_template rfc7539_tmpls[] = {
701 	{
702 		.name = "rfc7539",
703 		.create = rfc7539_create,
704 		.module = THIS_MODULE,
705 	}, {
706 		.name = "rfc7539esp",
707 		.create = rfc7539esp_create,
708 		.module = THIS_MODULE,
709 	},
710 };
711 
712 static int __init chacha20poly1305_module_init(void)
713 {
714 	return crypto_register_templates(rfc7539_tmpls,
715 					 ARRAY_SIZE(rfc7539_tmpls));
716 }
717 
718 static void __exit chacha20poly1305_module_exit(void)
719 {
720 	crypto_unregister_templates(rfc7539_tmpls,
721 				    ARRAY_SIZE(rfc7539_tmpls));
722 }
723 
724 subsys_initcall(chacha20poly1305_module_init);
725 module_exit(chacha20poly1305_module_exit);
726 
727 MODULE_LICENSE("GPL");
728 MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
729 MODULE_DESCRIPTION("ChaCha20-Poly1305 AEAD");
730 MODULE_ALIAS_CRYPTO("rfc7539");
731 MODULE_ALIAS_CRYPTO("rfc7539esp");
732