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Martin Willi71ebc4d2015-06-01 13:44:00 +02001/*
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>
Martin Willi31d72472015-07-16 19:14:00 +020016#include <crypto/chacha20.h>
Martin Willi2546f812015-07-16 19:14:05 +020017#include <crypto/poly1305.h>
Martin Willi71ebc4d2015-06-01 13:44:00 +020018#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
Martin Willi71ebc4d2015-06-01 13:44:00 +020025#define CHACHAPOLY_IV_SIZE 12
26
27struct chachapoly_instance_ctx {
28 struct crypto_skcipher_spawn chacha;
29 struct crypto_ahash_spawn poly;
30 unsigned int saltlen;
31};
32
33struct 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
41struct 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
53struct chacha_req {
Martin Willi71ebc4d2015-06-01 13:44:00 +020054 u8 iv[CHACHA20_IV_SIZE];
55 struct scatterlist src[1];
56 struct ablkcipher_request req; /* must be last member */
57};
58
59struct chachapoly_req_ctx {
Herbert Xu74790922015-07-16 12:35:08 +080060 struct scatterlist src[2];
61 struct scatterlist dst[2];
Martin Willic2b7b20a2015-06-16 11:34:16 +020062 /* the key we generate for Poly1305 using Chacha20 */
63 u8 key[POLY1305_KEY_SIZE];
Martin Willi71ebc4d2015-06-01 13:44:00 +020064 /* calculated Poly1305 tag */
65 u8 tag[POLY1305_DIGEST_SIZE];
66 /* length of data to en/decrypt, without ICV */
67 unsigned int cryptlen;
Herbert Xu74790922015-07-16 12:35:08 +080068 /* Actual AD, excluding IV */
69 unsigned int assoclen;
Martin Willi71ebc4d2015-06-01 13:44:00 +020070 union {
71 struct poly_req poly;
72 struct chacha_req chacha;
73 } u;
74};
75
76static 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
86static 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
97static 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
Herbert Xu74790922015-07-16 12:35:08 +0800102 scatterwalk_map_and_copy(tag, req->src,
103 req->assoclen + rctx->cryptlen,
104 sizeof(tag), 0);
Martin Willi71ebc4d2015-06-01 13:44:00 +0200105 if (crypto_memneq(tag, rctx->tag, sizeof(tag)))
106 return -EBADMSG;
107 return 0;
108}
109
110static int poly_copy_tag(struct aead_request *req)
111{
112 struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
113
Herbert Xu74790922015-07-16 12:35:08 +0800114 scatterwalk_map_and_copy(rctx->tag, req->dst,
115 req->assoclen + rctx->cryptlen,
Martin Willi71ebc4d2015-06-01 13:44:00 +0200116 sizeof(rctx->tag), 1);
117 return 0;
118}
119
120static void chacha_decrypt_done(struct crypto_async_request *areq, int err)
121{
122 async_done_continue(areq->data, err, poly_verify_tag);
123}
124
125static 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;
Herbert Xu74790922015-07-16 12:35:08 +0800130 struct scatterlist *src, *dst;
Martin Willi71ebc4d2015-06-01 13:44:00 +0200131 int err;
132
133 chacha_iv(creq->iv, req, 1);
134
Herbert Xu74790922015-07-16 12:35:08 +0800135 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
Martin Willi71ebc4d2015-06-01 13:44:00 +0200144 ablkcipher_request_set_callback(&creq->req, aead_request_flags(req),
145 chacha_decrypt_done, req);
146 ablkcipher_request_set_tfm(&creq->req, ctx->chacha);
Herbert Xu74790922015-07-16 12:35:08 +0800147 ablkcipher_request_set_crypt(&creq->req, src, dst,
Martin Willi71ebc4d2015-06-01 13:44:00 +0200148 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
156static 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
166static void poly_tail_done(struct crypto_async_request *areq, int err)
167{
168 async_done_continue(areq->data, err, poly_tail_continue);
169}
170
171static int poly_tail(struct aead_request *req)
172{
Herbert Xu74790922015-07-16 12:35:08 +0800173 struct crypto_aead *tfm = crypto_aead_reqtfm(req);
174 struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
Martin Willi71ebc4d2015-06-01 13:44:00 +0200175 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);
Herbert Xu74790922015-07-16 12:35:08 +0800181 len = cpu_to_le64(rctx->assoclen);
Martin Willi71ebc4d2015-06-01 13:44:00 +0200182 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
200static void poly_cipherpad_done(struct crypto_async_request *areq, int err)
201{
202 async_done_continue(areq->data, err, poly_tail);
203}
204
205static 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
230static void poly_cipher_done(struct crypto_async_request *areq, int err)
231{
232 async_done_continue(areq->data, err, poly_cipherpad);
233}
234
235static 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
Herbert Xu74790922015-07-16 12:35:08 +0800246 sg_init_table(rctx->src, 2);
247 crypt = scatterwalk_ffwd(rctx->src, crypt, req->assoclen);
248
Martin Willi71ebc4d2015-06-01 13:44:00 +0200249 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
261static void poly_adpad_done(struct crypto_async_request *areq, int err)
262{
263 async_done_continue(areq->data, err, poly_cipher);
264}
265
266static 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
Herbert Xu74790922015-07-16 12:35:08 +0800274 padlen = (bs - (rctx->assoclen % bs)) % bs;
Martin Willi71ebc4d2015-06-01 13:44:00 +0200275 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
291static void poly_ad_done(struct crypto_async_request *areq, int err)
292{
293 async_done_continue(areq->data, err, poly_adpad);
294}
295
296static 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);
Herbert Xu74790922015-07-16 12:35:08 +0800306 ahash_request_set_crypt(&preq->req, req->src, NULL, rctx->assoclen);
Martin Willi71ebc4d2015-06-01 13:44:00 +0200307
308 err = crypto_ahash_update(&preq->req);
309 if (err)
310 return err;
311
312 return poly_adpad(req);
313}
314
Martin Willic2b7b20a2015-06-16 11:34:16 +0200315static void poly_setkey_done(struct crypto_async_request *areq, int err)
Martin Willi71ebc4d2015-06-01 13:44:00 +0200316{
317 async_done_continue(areq->data, err, poly_ad);
318}
319
Martin Willic2b7b20a2015-06-16 11:34:16 +0200320static 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
342static void poly_init_done(struct crypto_async_request *areq, int err)
343{
344 async_done_continue(areq->data, err, poly_setkey);
345}
346
Martin Willi71ebc4d2015-06-01 13:44:00 +0200347static 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
Martin Willic2b7b20a2015-06-16 11:34:16 +0200362 return poly_setkey(req);
Martin Willi71ebc4d2015-06-01 13:44:00 +0200363}
364
365static void poly_genkey_done(struct crypto_async_request *areq, int err)
366{
Martin Willic2b7b20a2015-06-16 11:34:16 +0200367 async_done_continue(areq->data, err, poly_init);
Martin Willi71ebc4d2015-06-01 13:44:00 +0200368}
369
370static int poly_genkey(struct aead_request *req)
371{
Herbert Xu74790922015-07-16 12:35:08 +0800372 struct crypto_aead *tfm = crypto_aead_reqtfm(req);
373 struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
Martin Willi71ebc4d2015-06-01 13:44:00 +0200374 struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
375 struct chacha_req *creq = &rctx->u.chacha;
376 int err;
377
Herbert Xu74790922015-07-16 12:35:08 +0800378 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
Martin Willi71ebc4d2015-06-01 13:44:00 +0200386 sg_init_table(creq->src, 1);
Martin Willic2b7b20a2015-06-16 11:34:16 +0200387 memset(rctx->key, 0, sizeof(rctx->key));
388 sg_set_buf(creq->src, rctx->key, sizeof(rctx->key));
Martin Willi71ebc4d2015-06-01 13:44:00 +0200389
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
Martin Willic2b7b20a2015-06-16 11:34:16 +0200402 return poly_init(req);
Martin Willi71ebc4d2015-06-01 13:44:00 +0200403}
404
405static void chacha_encrypt_done(struct crypto_async_request *areq, int err)
406{
407 async_done_continue(areq->data, err, poly_genkey);
408}
409
410static 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;
Herbert Xu74790922015-07-16 12:35:08 +0800415 struct scatterlist *src, *dst;
Martin Willi71ebc4d2015-06-01 13:44:00 +0200416 int err;
417
418 chacha_iv(creq->iv, req, 1);
419
Herbert Xu74790922015-07-16 12:35:08 +0800420 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
Martin Willi71ebc4d2015-06-01 13:44:00 +0200429 ablkcipher_request_set_callback(&creq->req, aead_request_flags(req),
430 chacha_encrypt_done, req);
431 ablkcipher_request_set_tfm(&creq->req, ctx->chacha);
Herbert Xu74790922015-07-16 12:35:08 +0800432 ablkcipher_request_set_crypt(&creq->req, src, dst,
Martin Willi71ebc4d2015-06-01 13:44:00 +0200433 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
441static 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()
Martin Willic2b7b20a2015-06-16 11:34:16 +0200449 * - poly_genkey/done()
Martin Willi71ebc4d2015-06-01 13:44:00 +0200450 * - poly_init/done()
Martin Willic2b7b20a2015-06-16 11:34:16 +0200451 * - poly_setkey/done()
Martin Willi71ebc4d2015-06-01 13:44:00 +0200452 * - 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
462static int chachapoly_decrypt(struct aead_request *req)
463{
464 struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
465
Martin Willi71ebc4d2015-06-01 13:44:00 +0200466 rctx->cryptlen = req->cryptlen - POLY1305_DIGEST_SIZE;
467
468 /* decrypt call chain:
Martin Willic2b7b20a2015-06-16 11:34:16 +0200469 * - poly_genkey/done()
Martin Willi71ebc4d2015-06-01 13:44:00 +0200470 * - poly_init/done()
Martin Willic2b7b20a2015-06-16 11:34:16 +0200471 * - poly_setkey/done()
Martin Willi71ebc4d2015-06-01 13:44:00 +0200472 * - 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
483static 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
505static 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
Herbert Xu74790922015-07-16 12:35:08 +0800514static int chachapoly_init(struct crypto_aead *tfm)
Martin Willi71ebc4d2015-06-01 13:44:00 +0200515{
Herbert Xu74790922015-07-16 12:35:08 +0800516 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);
Martin Willi71ebc4d2015-06-01 13:44:00 +0200519 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
Herbert Xu74790922015-07-16 12:35:08 +0800537 align = crypto_aead_alignmask(tfm);
Martin Willi71ebc4d2015-06-01 13:44:00 +0200538 align &= ~(crypto_tfm_ctx_alignment() - 1);
Herbert Xu74790922015-07-16 12:35:08 +0800539 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)));
Martin Willi71ebc4d2015-06-01 13:44:00 +0200548
549 return 0;
550}
551
Herbert Xu74790922015-07-16 12:35:08 +0800552static void chachapoly_exit(struct crypto_aead *tfm)
Martin Willi71ebc4d2015-06-01 13:44:00 +0200553{
Herbert Xu74790922015-07-16 12:35:08 +0800554 struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
Martin Willi71ebc4d2015-06-01 13:44:00 +0200555
556 crypto_free_ahash(ctx->poly);
557 crypto_free_ablkcipher(ctx->chacha);
558}
559
Herbert Xu74790922015-07-16 12:35:08 +0800560static 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
569static int chachapoly_create(struct crypto_template *tmpl, struct rtattr **tb,
570 const char *name, unsigned int ivsize)
Martin Willi71ebc4d2015-06-01 13:44:00 +0200571{
572 struct crypto_attr_type *algt;
Herbert Xu74790922015-07-16 12:35:08 +0800573 struct aead_instance *inst;
Martin Willi71ebc4d2015-06-01 13:44:00 +0200574 struct crypto_alg *chacha;
575 struct crypto_alg *poly;
Herbert Xu74790922015-07-16 12:35:08 +0800576 struct hash_alg_common *poly_hash;
Martin Willi71ebc4d2015-06-01 13:44:00 +0200577 struct chachapoly_instance_ctx *ctx;
578 const char *chacha_name, *poly_name;
579 int err;
580
581 if (ivsize > CHACHAPOLY_IV_SIZE)
Herbert Xu74790922015-07-16 12:35:08 +0800582 return -EINVAL;
Martin Willi71ebc4d2015-06-01 13:44:00 +0200583
584 algt = crypto_get_attr_type(tb);
585 if (IS_ERR(algt))
Herbert Xu74790922015-07-16 12:35:08 +0800586 return PTR_ERR(algt);
Martin Willi71ebc4d2015-06-01 13:44:00 +0200587
Herbert Xu5e4b8c12015-08-13 17:29:06 +0800588 if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
Herbert Xu74790922015-07-16 12:35:08 +0800589 return -EINVAL;
Martin Willi71ebc4d2015-06-01 13:44:00 +0200590
591 chacha_name = crypto_attr_alg_name(tb[1]);
592 if (IS_ERR(chacha_name))
Herbert Xu74790922015-07-16 12:35:08 +0800593 return PTR_ERR(chacha_name);
Martin Willi71ebc4d2015-06-01 13:44:00 +0200594 poly_name = crypto_attr_alg_name(tb[2]);
595 if (IS_ERR(poly_name))
Herbert Xu74790922015-07-16 12:35:08 +0800596 return PTR_ERR(poly_name);
Martin Willi71ebc4d2015-06-01 13:44:00 +0200597
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))
Herbert Xu74790922015-07-16 12:35:08 +0800602 return PTR_ERR(poly);
Martin Willi71ebc4d2015-06-01 13:44:00 +0200603
604 err = -ENOMEM;
605 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
606 if (!inst)
607 goto out_put_poly;
608
Herbert Xu74790922015-07-16 12:35:08 +0800609 ctx = aead_instance_ctx(inst);
Martin Willi71ebc4d2015-06-01 13:44:00 +0200610 ctx->saltlen = CHACHAPOLY_IV_SIZE - ivsize;
Herbert Xu74790922015-07-16 12:35:08 +0800611 poly_hash = __crypto_hash_alg_common(poly);
612 err = crypto_init_ahash_spawn(&ctx->poly, poly_hash,
613 aead_crypto_instance(inst));
Martin Willi71ebc4d2015-06-01 13:44:00 +0200614 if (err)
615 goto err_free_inst;
616
Herbert Xu74790922015-07-16 12:35:08 +0800617 crypto_set_skcipher_spawn(&ctx->chacha, aead_crypto_instance(inst));
Martin Willi71ebc4d2015-06-01 13:44:00 +0200618 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;
Herbert Xu74790922015-07-16 12:35:08 +0800635 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
Martin Willi71ebc4d2015-06-01 13:44:00 +0200636 "%s(%s,%s)", name, chacha_name,
637 poly_name) >= CRYPTO_MAX_ALG_NAME)
638 goto out_drop_chacha;
Herbert Xu74790922015-07-16 12:35:08 +0800639 if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
Martin Willi71ebc4d2015-06-01 13:44:00 +0200640 "%s(%s,%s)", name, chacha->cra_driver_name,
641 poly->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
642 goto out_drop_chacha;
643
Herbert Xu74790922015-07-16 12:35:08 +0800644 inst->alg.base.cra_flags = (chacha->cra_flags | poly->cra_flags) &
645 CRYPTO_ALG_ASYNC;
Herbert Xu74790922015-07-16 12:35:08 +0800646 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;
Martin Willi71ebc4d2015-06-01 13:44:00 +0200661
Herbert Xu74790922015-07-16 12:35:08 +0800662 inst->free = chachapoly_free;
663
664 err = aead_register_instance(tmpl, inst);
665 if (err)
666 goto out_drop_chacha;
667
668out_put_poly:
Martin Willi71ebc4d2015-06-01 13:44:00 +0200669 crypto_mod_put(poly);
Herbert Xu74790922015-07-16 12:35:08 +0800670 return err;
Martin Willi71ebc4d2015-06-01 13:44:00 +0200671
672out_drop_chacha:
673 crypto_drop_skcipher(&ctx->chacha);
674err_drop_poly:
675 crypto_drop_ahash(&ctx->poly);
676err_free_inst:
677 kfree(inst);
Herbert Xu74790922015-07-16 12:35:08 +0800678 goto out_put_poly;
Martin Willi71ebc4d2015-06-01 13:44:00 +0200679}
680
Herbert Xu74790922015-07-16 12:35:08 +0800681static int rfc7539_create(struct crypto_template *tmpl, struct rtattr **tb)
Martin Willi71ebc4d2015-06-01 13:44:00 +0200682{
Herbert Xu74790922015-07-16 12:35:08 +0800683 return chachapoly_create(tmpl, tb, "rfc7539", 12);
Martin Willi71ebc4d2015-06-01 13:44:00 +0200684}
685
Herbert Xu74790922015-07-16 12:35:08 +0800686static int rfc7539esp_create(struct crypto_template *tmpl, struct rtattr **tb)
Martin Willi4db4ad22015-06-01 13:44:02 +0200687{
Herbert Xu74790922015-07-16 12:35:08 +0800688 return chachapoly_create(tmpl, tb, "rfc7539esp", 8);
Martin Willi71ebc4d2015-06-01 13:44:00 +0200689}
690
691static struct crypto_template rfc7539_tmpl = {
692 .name = "rfc7539",
Herbert Xu74790922015-07-16 12:35:08 +0800693 .create = rfc7539_create,
Martin Willi71ebc4d2015-06-01 13:44:00 +0200694 .module = THIS_MODULE,
695};
696
Martin Willi4db4ad22015-06-01 13:44:02 +0200697static struct crypto_template rfc7539esp_tmpl = {
698 .name = "rfc7539esp",
Herbert Xu74790922015-07-16 12:35:08 +0800699 .create = rfc7539esp_create,
Martin Willi4db4ad22015-06-01 13:44:02 +0200700 .module = THIS_MODULE,
701};
702
Martin Willi71ebc4d2015-06-01 13:44:00 +0200703static int __init chacha20poly1305_module_init(void)
704{
Martin Willi4db4ad22015-06-01 13:44:02 +0200705 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;
Martin Willi71ebc4d2015-06-01 13:44:00 +0200716}
717
718static void __exit chacha20poly1305_module_exit(void)
719{
Martin Willi4db4ad22015-06-01 13:44:02 +0200720 crypto_unregister_template(&rfc7539esp_tmpl);
Martin Willi71ebc4d2015-06-01 13:44:00 +0200721 crypto_unregister_template(&rfc7539_tmpl);
722}
723
724module_init(chacha20poly1305_module_init);
725module_exit(chacha20poly1305_module_exit);
726
727MODULE_LICENSE("GPL");
728MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
729MODULE_DESCRIPTION("ChaCha20-Poly1305 AEAD");
Martin Willi71ebc4d2015-06-01 13:44:00 +0200730MODULE_ALIAS_CRYPTO("rfc7539");
Martin Willi4db4ad22015-06-01 13:44:02 +0200731MODULE_ALIAS_CRYPTO("rfc7539esp");