xref: /linux/crypto/chacha20poly1305.c (revision b85d45947951d23cb22d90caecf4c1eb81342c96)
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_ablkcipher *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 ablkcipher_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 	chacha_iv(creq->iv, req, 1);
134 
135 	sg_init_table(rctx->src, 2);
136 	src = scatterwalk_ffwd(rctx->src, req->src, req->assoclen);
137 	dst = src;
138 
139 	if (req->src != req->dst) {
140 		sg_init_table(rctx->dst, 2);
141 		dst = scatterwalk_ffwd(rctx->dst, req->dst, req->assoclen);
142 	}
143 
144 	ablkcipher_request_set_callback(&creq->req, aead_request_flags(req),
145 					chacha_decrypt_done, req);
146 	ablkcipher_request_set_tfm(&creq->req, ctx->chacha);
147 	ablkcipher_request_set_crypt(&creq->req, src, dst,
148 				     rctx->cryptlen, creq->iv);
149 	err = crypto_ablkcipher_decrypt(&creq->req);
150 	if (err)
151 		return err;
152 
153 	return poly_verify_tag(req);
154 }
155 
156 static int poly_tail_continue(struct aead_request *req)
157 {
158 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
159 
160 	if (rctx->cryptlen == req->cryptlen) /* encrypting */
161 		return poly_copy_tag(req);
162 
163 	return chacha_decrypt(req);
164 }
165 
166 static void poly_tail_done(struct crypto_async_request *areq, int err)
167 {
168 	async_done_continue(areq->data, err, poly_tail_continue);
169 }
170 
171 static int poly_tail(struct aead_request *req)
172 {
173 	struct crypto_aead *tfm = crypto_aead_reqtfm(req);
174 	struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
175 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
176 	struct poly_req *preq = &rctx->u.poly;
177 	__le64 len;
178 	int err;
179 
180 	sg_init_table(preq->src, 1);
181 	len = cpu_to_le64(rctx->assoclen);
182 	memcpy(&preq->tail.assoclen, &len, sizeof(len));
183 	len = cpu_to_le64(rctx->cryptlen);
184 	memcpy(&preq->tail.cryptlen, &len, sizeof(len));
185 	sg_set_buf(preq->src, &preq->tail, sizeof(preq->tail));
186 
187 	ahash_request_set_callback(&preq->req, aead_request_flags(req),
188 				   poly_tail_done, req);
189 	ahash_request_set_tfm(&preq->req, ctx->poly);
190 	ahash_request_set_crypt(&preq->req, preq->src,
191 				rctx->tag, sizeof(preq->tail));
192 
193 	err = crypto_ahash_finup(&preq->req);
194 	if (err)
195 		return err;
196 
197 	return poly_tail_continue(req);
198 }
199 
200 static void poly_cipherpad_done(struct crypto_async_request *areq, int err)
201 {
202 	async_done_continue(areq->data, err, poly_tail);
203 }
204 
205 static int poly_cipherpad(struct aead_request *req)
206 {
207 	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
208 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
209 	struct poly_req *preq = &rctx->u.poly;
210 	unsigned int padlen, bs = POLY1305_BLOCK_SIZE;
211 	int err;
212 
213 	padlen = (bs - (rctx->cryptlen % bs)) % bs;
214 	memset(preq->pad, 0, sizeof(preq->pad));
215 	sg_init_table(preq->src, 1);
216 	sg_set_buf(preq->src, &preq->pad, padlen);
217 
218 	ahash_request_set_callback(&preq->req, aead_request_flags(req),
219 				   poly_cipherpad_done, req);
220 	ahash_request_set_tfm(&preq->req, ctx->poly);
221 	ahash_request_set_crypt(&preq->req, preq->src, NULL, padlen);
222 
223 	err = crypto_ahash_update(&preq->req);
224 	if (err)
225 		return err;
226 
227 	return poly_tail(req);
228 }
229 
230 static void poly_cipher_done(struct crypto_async_request *areq, int err)
231 {
232 	async_done_continue(areq->data, err, poly_cipherpad);
233 }
234 
235 static int poly_cipher(struct aead_request *req)
236 {
237 	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
238 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
239 	struct poly_req *preq = &rctx->u.poly;
240 	struct scatterlist *crypt = req->src;
241 	int err;
242 
243 	if (rctx->cryptlen == req->cryptlen) /* encrypting */
244 		crypt = req->dst;
245 
246 	sg_init_table(rctx->src, 2);
247 	crypt = scatterwalk_ffwd(rctx->src, crypt, req->assoclen);
248 
249 	ahash_request_set_callback(&preq->req, aead_request_flags(req),
250 				   poly_cipher_done, req);
251 	ahash_request_set_tfm(&preq->req, ctx->poly);
252 	ahash_request_set_crypt(&preq->req, crypt, NULL, rctx->cryptlen);
253 
254 	err = crypto_ahash_update(&preq->req);
255 	if (err)
256 		return err;
257 
258 	return poly_cipherpad(req);
259 }
260 
261 static void poly_adpad_done(struct crypto_async_request *areq, int err)
262 {
263 	async_done_continue(areq->data, err, poly_cipher);
264 }
265 
266 static int poly_adpad(struct aead_request *req)
267 {
268 	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
269 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
270 	struct poly_req *preq = &rctx->u.poly;
271 	unsigned int padlen, bs = POLY1305_BLOCK_SIZE;
272 	int err;
273 
274 	padlen = (bs - (rctx->assoclen % bs)) % bs;
275 	memset(preq->pad, 0, sizeof(preq->pad));
276 	sg_init_table(preq->src, 1);
277 	sg_set_buf(preq->src, preq->pad, padlen);
278 
279 	ahash_request_set_callback(&preq->req, aead_request_flags(req),
280 				   poly_adpad_done, req);
281 	ahash_request_set_tfm(&preq->req, ctx->poly);
282 	ahash_request_set_crypt(&preq->req, preq->src, NULL, padlen);
283 
284 	err = crypto_ahash_update(&preq->req);
285 	if (err)
286 		return err;
287 
288 	return poly_cipher(req);
289 }
290 
291 static void poly_ad_done(struct crypto_async_request *areq, int err)
292 {
293 	async_done_continue(areq->data, err, poly_adpad);
294 }
295 
296 static int poly_ad(struct aead_request *req)
297 {
298 	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
299 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
300 	struct poly_req *preq = &rctx->u.poly;
301 	int err;
302 
303 	ahash_request_set_callback(&preq->req, aead_request_flags(req),
304 				   poly_ad_done, req);
305 	ahash_request_set_tfm(&preq->req, ctx->poly);
306 	ahash_request_set_crypt(&preq->req, req->src, NULL, rctx->assoclen);
307 
308 	err = crypto_ahash_update(&preq->req);
309 	if (err)
310 		return err;
311 
312 	return poly_adpad(req);
313 }
314 
315 static void poly_setkey_done(struct crypto_async_request *areq, int err)
316 {
317 	async_done_continue(areq->data, err, poly_ad);
318 }
319 
320 static int poly_setkey(struct aead_request *req)
321 {
322 	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
323 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
324 	struct poly_req *preq = &rctx->u.poly;
325 	int err;
326 
327 	sg_init_table(preq->src, 1);
328 	sg_set_buf(preq->src, rctx->key, sizeof(rctx->key));
329 
330 	ahash_request_set_callback(&preq->req, aead_request_flags(req),
331 				   poly_setkey_done, req);
332 	ahash_request_set_tfm(&preq->req, ctx->poly);
333 	ahash_request_set_crypt(&preq->req, preq->src, NULL, sizeof(rctx->key));
334 
335 	err = crypto_ahash_update(&preq->req);
336 	if (err)
337 		return err;
338 
339 	return poly_ad(req);
340 }
341 
342 static void poly_init_done(struct crypto_async_request *areq, int err)
343 {
344 	async_done_continue(areq->data, err, poly_setkey);
345 }
346 
347 static int poly_init(struct aead_request *req)
348 {
349 	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
350 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
351 	struct poly_req *preq = &rctx->u.poly;
352 	int err;
353 
354 	ahash_request_set_callback(&preq->req, aead_request_flags(req),
355 				   poly_init_done, req);
356 	ahash_request_set_tfm(&preq->req, ctx->poly);
357 
358 	err = crypto_ahash_init(&preq->req);
359 	if (err)
360 		return err;
361 
362 	return poly_setkey(req);
363 }
364 
365 static void poly_genkey_done(struct crypto_async_request *areq, int err)
366 {
367 	async_done_continue(areq->data, err, poly_init);
368 }
369 
370 static int poly_genkey(struct aead_request *req)
371 {
372 	struct crypto_aead *tfm = crypto_aead_reqtfm(req);
373 	struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
374 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
375 	struct chacha_req *creq = &rctx->u.chacha;
376 	int err;
377 
378 	rctx->assoclen = req->assoclen;
379 
380 	if (crypto_aead_ivsize(tfm) == 8) {
381 		if (rctx->assoclen < 8)
382 			return -EINVAL;
383 		rctx->assoclen -= 8;
384 	}
385 
386 	sg_init_table(creq->src, 1);
387 	memset(rctx->key, 0, sizeof(rctx->key));
388 	sg_set_buf(creq->src, rctx->key, sizeof(rctx->key));
389 
390 	chacha_iv(creq->iv, req, 0);
391 
392 	ablkcipher_request_set_callback(&creq->req, aead_request_flags(req),
393 					poly_genkey_done, req);
394 	ablkcipher_request_set_tfm(&creq->req, ctx->chacha);
395 	ablkcipher_request_set_crypt(&creq->req, creq->src, creq->src,
396 				     POLY1305_KEY_SIZE, creq->iv);
397 
398 	err = crypto_ablkcipher_decrypt(&creq->req);
399 	if (err)
400 		return err;
401 
402 	return poly_init(req);
403 }
404 
405 static void chacha_encrypt_done(struct crypto_async_request *areq, int err)
406 {
407 	async_done_continue(areq->data, err, poly_genkey);
408 }
409 
410 static int chacha_encrypt(struct aead_request *req)
411 {
412 	struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
413 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
414 	struct chacha_req *creq = &rctx->u.chacha;
415 	struct scatterlist *src, *dst;
416 	int err;
417 
418 	chacha_iv(creq->iv, req, 1);
419 
420 	sg_init_table(rctx->src, 2);
421 	src = scatterwalk_ffwd(rctx->src, req->src, req->assoclen);
422 	dst = src;
423 
424 	if (req->src != req->dst) {
425 		sg_init_table(rctx->dst, 2);
426 		dst = scatterwalk_ffwd(rctx->dst, req->dst, req->assoclen);
427 	}
428 
429 	ablkcipher_request_set_callback(&creq->req, aead_request_flags(req),
430 					chacha_encrypt_done, req);
431 	ablkcipher_request_set_tfm(&creq->req, ctx->chacha);
432 	ablkcipher_request_set_crypt(&creq->req, src, dst,
433 				     req->cryptlen, creq->iv);
434 	err = crypto_ablkcipher_encrypt(&creq->req);
435 	if (err)
436 		return err;
437 
438 	return poly_genkey(req);
439 }
440 
441 static int chachapoly_encrypt(struct aead_request *req)
442 {
443 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
444 
445 	rctx->cryptlen = req->cryptlen;
446 
447 	/* encrypt call chain:
448 	 * - chacha_encrypt/done()
449 	 * - poly_genkey/done()
450 	 * - poly_init/done()
451 	 * - poly_setkey/done()
452 	 * - poly_ad/done()
453 	 * - poly_adpad/done()
454 	 * - poly_cipher/done()
455 	 * - poly_cipherpad/done()
456 	 * - poly_tail/done/continue()
457 	 * - poly_copy_tag()
458 	 */
459 	return chacha_encrypt(req);
460 }
461 
462 static int chachapoly_decrypt(struct aead_request *req)
463 {
464 	struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
465 
466 	rctx->cryptlen = req->cryptlen - POLY1305_DIGEST_SIZE;
467 
468 	/* decrypt call chain:
469 	 * - poly_genkey/done()
470 	 * - poly_init/done()
471 	 * - poly_setkey/done()
472 	 * - poly_ad/done()
473 	 * - poly_adpad/done()
474 	 * - poly_cipher/done()
475 	 * - poly_cipherpad/done()
476 	 * - poly_tail/done/continue()
477 	 * - chacha_decrypt/done()
478 	 * - poly_verify_tag()
479 	 */
480 	return poly_genkey(req);
481 }
482 
483 static int chachapoly_setkey(struct crypto_aead *aead, const u8 *key,
484 			     unsigned int keylen)
485 {
486 	struct chachapoly_ctx *ctx = crypto_aead_ctx(aead);
487 	int err;
488 
489 	if (keylen != ctx->saltlen + CHACHA20_KEY_SIZE)
490 		return -EINVAL;
491 
492 	keylen -= ctx->saltlen;
493 	memcpy(ctx->salt, key + keylen, ctx->saltlen);
494 
495 	crypto_ablkcipher_clear_flags(ctx->chacha, CRYPTO_TFM_REQ_MASK);
496 	crypto_ablkcipher_set_flags(ctx->chacha, crypto_aead_get_flags(aead) &
497 				    CRYPTO_TFM_REQ_MASK);
498 
499 	err = crypto_ablkcipher_setkey(ctx->chacha, key, keylen);
500 	crypto_aead_set_flags(aead, crypto_ablkcipher_get_flags(ctx->chacha) &
501 			      CRYPTO_TFM_RES_MASK);
502 	return err;
503 }
504 
505 static int chachapoly_setauthsize(struct crypto_aead *tfm,
506 				  unsigned int authsize)
507 {
508 	if (authsize != POLY1305_DIGEST_SIZE)
509 		return -EINVAL;
510 
511 	return 0;
512 }
513 
514 static int chachapoly_init(struct crypto_aead *tfm)
515 {
516 	struct aead_instance *inst = aead_alg_instance(tfm);
517 	struct chachapoly_instance_ctx *ictx = aead_instance_ctx(inst);
518 	struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
519 	struct crypto_ablkcipher *chacha;
520 	struct crypto_ahash *poly;
521 	unsigned long align;
522 
523 	poly = crypto_spawn_ahash(&ictx->poly);
524 	if (IS_ERR(poly))
525 		return PTR_ERR(poly);
526 
527 	chacha = crypto_spawn_skcipher(&ictx->chacha);
528 	if (IS_ERR(chacha)) {
529 		crypto_free_ahash(poly);
530 		return PTR_ERR(chacha);
531 	}
532 
533 	ctx->chacha = chacha;
534 	ctx->poly = poly;
535 	ctx->saltlen = ictx->saltlen;
536 
537 	align = crypto_aead_alignmask(tfm);
538 	align &= ~(crypto_tfm_ctx_alignment() - 1);
539 	crypto_aead_set_reqsize(
540 		tfm,
541 		align + offsetof(struct chachapoly_req_ctx, u) +
542 		max(offsetof(struct chacha_req, req) +
543 		    sizeof(struct ablkcipher_request) +
544 		    crypto_ablkcipher_reqsize(chacha),
545 		    offsetof(struct poly_req, req) +
546 		    sizeof(struct ahash_request) +
547 		    crypto_ahash_reqsize(poly)));
548 
549 	return 0;
550 }
551 
552 static void chachapoly_exit(struct crypto_aead *tfm)
553 {
554 	struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
555 
556 	crypto_free_ahash(ctx->poly);
557 	crypto_free_ablkcipher(ctx->chacha);
558 }
559 
560 static void chachapoly_free(struct aead_instance *inst)
561 {
562 	struct chachapoly_instance_ctx *ctx = aead_instance_ctx(inst);
563 
564 	crypto_drop_skcipher(&ctx->chacha);
565 	crypto_drop_ahash(&ctx->poly);
566 	kfree(inst);
567 }
568 
569 static int chachapoly_create(struct crypto_template *tmpl, struct rtattr **tb,
570 			     const char *name, unsigned int ivsize)
571 {
572 	struct crypto_attr_type *algt;
573 	struct aead_instance *inst;
574 	struct crypto_alg *chacha;
575 	struct crypto_alg *poly;
576 	struct hash_alg_common *poly_hash;
577 	struct chachapoly_instance_ctx *ctx;
578 	const char *chacha_name, *poly_name;
579 	int err;
580 
581 	if (ivsize > CHACHAPOLY_IV_SIZE)
582 		return -EINVAL;
583 
584 	algt = crypto_get_attr_type(tb);
585 	if (IS_ERR(algt))
586 		return PTR_ERR(algt);
587 
588 	if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
589 		return -EINVAL;
590 
591 	chacha_name = crypto_attr_alg_name(tb[1]);
592 	if (IS_ERR(chacha_name))
593 		return PTR_ERR(chacha_name);
594 	poly_name = crypto_attr_alg_name(tb[2]);
595 	if (IS_ERR(poly_name))
596 		return PTR_ERR(poly_name);
597 
598 	poly = crypto_find_alg(poly_name, &crypto_ahash_type,
599 			       CRYPTO_ALG_TYPE_HASH,
600 			       CRYPTO_ALG_TYPE_AHASH_MASK);
601 	if (IS_ERR(poly))
602 		return PTR_ERR(poly);
603 
604 	err = -ENOMEM;
605 	inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
606 	if (!inst)
607 		goto out_put_poly;
608 
609 	ctx = aead_instance_ctx(inst);
610 	ctx->saltlen = CHACHAPOLY_IV_SIZE - ivsize;
611 	poly_hash = __crypto_hash_alg_common(poly);
612 	err = crypto_init_ahash_spawn(&ctx->poly, poly_hash,
613 				      aead_crypto_instance(inst));
614 	if (err)
615 		goto err_free_inst;
616 
617 	crypto_set_skcipher_spawn(&ctx->chacha, aead_crypto_instance(inst));
618 	err = crypto_grab_skcipher(&ctx->chacha, chacha_name, 0,
619 				   crypto_requires_sync(algt->type,
620 							algt->mask));
621 	if (err)
622 		goto err_drop_poly;
623 
624 	chacha = crypto_skcipher_spawn_alg(&ctx->chacha);
625 
626 	err = -EINVAL;
627 	/* Need 16-byte IV size, including Initial Block Counter value */
628 	if (chacha->cra_ablkcipher.ivsize != CHACHA20_IV_SIZE)
629 		goto out_drop_chacha;
630 	/* Not a stream cipher? */
631 	if (chacha->cra_blocksize != 1)
632 		goto out_drop_chacha;
633 
634 	err = -ENAMETOOLONG;
635 	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
636 		     "%s(%s,%s)", name, chacha_name,
637 		     poly_name) >= CRYPTO_MAX_ALG_NAME)
638 		goto out_drop_chacha;
639 	if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
640 		     "%s(%s,%s)", name, chacha->cra_driver_name,
641 		     poly->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
642 		goto out_drop_chacha;
643 
644 	inst->alg.base.cra_flags = (chacha->cra_flags | poly->cra_flags) &
645 				   CRYPTO_ALG_ASYNC;
646 	inst->alg.base.cra_priority = (chacha->cra_priority +
647 				       poly->cra_priority) / 2;
648 	inst->alg.base.cra_blocksize = 1;
649 	inst->alg.base.cra_alignmask = chacha->cra_alignmask |
650 				       poly->cra_alignmask;
651 	inst->alg.base.cra_ctxsize = sizeof(struct chachapoly_ctx) +
652 				     ctx->saltlen;
653 	inst->alg.ivsize = ivsize;
654 	inst->alg.maxauthsize = POLY1305_DIGEST_SIZE;
655 	inst->alg.init = chachapoly_init;
656 	inst->alg.exit = chachapoly_exit;
657 	inst->alg.encrypt = chachapoly_encrypt;
658 	inst->alg.decrypt = chachapoly_decrypt;
659 	inst->alg.setkey = chachapoly_setkey;
660 	inst->alg.setauthsize = chachapoly_setauthsize;
661 
662 	inst->free = chachapoly_free;
663 
664 	err = aead_register_instance(tmpl, inst);
665 	if (err)
666 		goto out_drop_chacha;
667 
668 out_put_poly:
669 	crypto_mod_put(poly);
670 	return err;
671 
672 out_drop_chacha:
673 	crypto_drop_skcipher(&ctx->chacha);
674 err_drop_poly:
675 	crypto_drop_ahash(&ctx->poly);
676 err_free_inst:
677 	kfree(inst);
678 	goto out_put_poly;
679 }
680 
681 static int rfc7539_create(struct crypto_template *tmpl, struct rtattr **tb)
682 {
683 	return chachapoly_create(tmpl, tb, "rfc7539", 12);
684 }
685 
686 static int rfc7539esp_create(struct crypto_template *tmpl, struct rtattr **tb)
687 {
688 	return chachapoly_create(tmpl, tb, "rfc7539esp", 8);
689 }
690 
691 static struct crypto_template rfc7539_tmpl = {
692 	.name = "rfc7539",
693 	.create = rfc7539_create,
694 	.module = THIS_MODULE,
695 };
696 
697 static struct crypto_template rfc7539esp_tmpl = {
698 	.name = "rfc7539esp",
699 	.create = rfc7539esp_create,
700 	.module = THIS_MODULE,
701 };
702 
703 static int __init chacha20poly1305_module_init(void)
704 {
705 	int err;
706 
707 	err = crypto_register_template(&rfc7539_tmpl);
708 	if (err)
709 		return err;
710 
711 	err = crypto_register_template(&rfc7539esp_tmpl);
712 	if (err)
713 		crypto_unregister_template(&rfc7539_tmpl);
714 
715 	return err;
716 }
717 
718 static void __exit chacha20poly1305_module_exit(void)
719 {
720 	crypto_unregister_template(&rfc7539esp_tmpl);
721 	crypto_unregister_template(&rfc7539_tmpl);
722 }
723 
724 module_init(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