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1 | // SPDX-License-Identifier: GPL-2.0-or-later | |
2 | /* | |
3 | * Authenc: Simple AEAD wrapper for IPsec | |
4 | * | |
5 | * Copyright (c) 2007-2015 Herbert Xu <herbert@gondor.apana.org.au> | |
6 | */ | |
7 | ||
8 | #include <crypto/internal/aead.h> | |
9 | #include <crypto/internal/hash.h> | |
10 | #include <crypto/internal/skcipher.h> | |
11 | #include <crypto/authenc.h> | |
12 | #include <crypto/null.h> | |
13 | #include <crypto/scatterwalk.h> | |
14 | #include <linux/err.h> | |
15 | #include <linux/init.h> | |
16 | #include <linux/kernel.h> | |
17 | #include <linux/module.h> | |
18 | #include <linux/rtnetlink.h> | |
19 | #include <linux/slab.h> | |
20 | #include <linux/spinlock.h> | |
21 | ||
22 | struct authenc_instance_ctx { | |
23 | struct crypto_ahash_spawn auth; | |
24 | struct crypto_skcipher_spawn enc; | |
25 | unsigned int reqoff; | |
26 | }; | |
27 | ||
28 | struct crypto_authenc_ctx { | |
29 | struct crypto_ahash *auth; | |
30 | struct crypto_skcipher *enc; | |
31 | struct crypto_sync_skcipher *null; | |
32 | }; | |
33 | ||
34 | struct authenc_request_ctx { | |
35 | struct scatterlist src[2]; | |
36 | struct scatterlist dst[2]; | |
37 | char tail[]; | |
38 | }; | |
39 | ||
40 | static void authenc_request_complete(struct aead_request *req, int err) | |
41 | { | |
42 | if (err != -EINPROGRESS) | |
43 | aead_request_complete(req, err); | |
44 | } | |
45 | ||
46 | int crypto_authenc_extractkeys(struct crypto_authenc_keys *keys, const u8 *key, | |
47 | unsigned int keylen) | |
48 | { | |
49 | struct rtattr *rta = (struct rtattr *)key; | |
50 | struct crypto_authenc_key_param *param; | |
51 | ||
52 | if (!RTA_OK(rta, keylen)) | |
53 | return -EINVAL; | |
54 | if (rta->rta_type != CRYPTO_AUTHENC_KEYA_PARAM) | |
55 | return -EINVAL; | |
56 | ||
57 | /* | |
58 | * RTA_OK() didn't align the rtattr's payload when validating that it | |
59 | * fits in the buffer. Yet, the keys should start on the next 4-byte | |
60 | * aligned boundary. To avoid confusion, require that the rtattr | |
61 | * payload be exactly the param struct, which has a 4-byte aligned size. | |
62 | */ | |
63 | if (RTA_PAYLOAD(rta) != sizeof(*param)) | |
64 | return -EINVAL; | |
65 | BUILD_BUG_ON(sizeof(*param) % RTA_ALIGNTO); | |
66 | ||
67 | param = RTA_DATA(rta); | |
68 | keys->enckeylen = be32_to_cpu(param->enckeylen); | |
69 | ||
70 | key += rta->rta_len; | |
71 | keylen -= rta->rta_len; | |
72 | ||
73 | if (keylen < keys->enckeylen) | |
74 | return -EINVAL; | |
75 | ||
76 | keys->authkeylen = keylen - keys->enckeylen; | |
77 | keys->authkey = key; | |
78 | keys->enckey = key + keys->authkeylen; | |
79 | ||
80 | return 0; | |
81 | } | |
82 | EXPORT_SYMBOL_GPL(crypto_authenc_extractkeys); | |
83 | ||
84 | static int crypto_authenc_setkey(struct crypto_aead *authenc, const u8 *key, | |
85 | unsigned int keylen) | |
86 | { | |
87 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); | |
88 | struct crypto_ahash *auth = ctx->auth; | |
89 | struct crypto_skcipher *enc = ctx->enc; | |
90 | struct crypto_authenc_keys keys; | |
91 | int err = -EINVAL; | |
92 | ||
93 | if (crypto_authenc_extractkeys(&keys, key, keylen) != 0) | |
94 | goto badkey; | |
95 | ||
96 | crypto_ahash_clear_flags(auth, CRYPTO_TFM_REQ_MASK); | |
97 | crypto_ahash_set_flags(auth, crypto_aead_get_flags(authenc) & | |
98 | CRYPTO_TFM_REQ_MASK); | |
99 | err = crypto_ahash_setkey(auth, keys.authkey, keys.authkeylen); | |
100 | crypto_aead_set_flags(authenc, crypto_ahash_get_flags(auth) & | |
101 | CRYPTO_TFM_RES_MASK); | |
102 | ||
103 | if (err) | |
104 | goto out; | |
105 | ||
106 | crypto_skcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK); | |
107 | crypto_skcipher_set_flags(enc, crypto_aead_get_flags(authenc) & | |
108 | CRYPTO_TFM_REQ_MASK); | |
109 | err = crypto_skcipher_setkey(enc, keys.enckey, keys.enckeylen); | |
110 | crypto_aead_set_flags(authenc, crypto_skcipher_get_flags(enc) & | |
111 | CRYPTO_TFM_RES_MASK); | |
112 | ||
113 | out: | |
114 | memzero_explicit(&keys, sizeof(keys)); | |
115 | return err; | |
116 | ||
117 | badkey: | |
118 | crypto_aead_set_flags(authenc, CRYPTO_TFM_RES_BAD_KEY_LEN); | |
119 | goto out; | |
120 | } | |
121 | ||
122 | static void authenc_geniv_ahash_done(struct crypto_async_request *areq, int err) | |
123 | { | |
124 | struct aead_request *req = areq->data; | |
125 | struct crypto_aead *authenc = crypto_aead_reqtfm(req); | |
126 | struct aead_instance *inst = aead_alg_instance(authenc); | |
127 | struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); | |
128 | struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); | |
129 | struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); | |
130 | ||
131 | if (err) | |
132 | goto out; | |
133 | ||
134 | scatterwalk_map_and_copy(ahreq->result, req->dst, | |
135 | req->assoclen + req->cryptlen, | |
136 | crypto_aead_authsize(authenc), 1); | |
137 | ||
138 | out: | |
139 | aead_request_complete(req, err); | |
140 | } | |
141 | ||
142 | static int crypto_authenc_genicv(struct aead_request *req, unsigned int flags) | |
143 | { | |
144 | struct crypto_aead *authenc = crypto_aead_reqtfm(req); | |
145 | struct aead_instance *inst = aead_alg_instance(authenc); | |
146 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); | |
147 | struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); | |
148 | struct crypto_ahash *auth = ctx->auth; | |
149 | struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); | |
150 | struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); | |
151 | u8 *hash = areq_ctx->tail; | |
152 | int err; | |
153 | ||
154 | hash = (u8 *)ALIGN((unsigned long)hash + crypto_ahash_alignmask(auth), | |
155 | crypto_ahash_alignmask(auth) + 1); | |
156 | ||
157 | ahash_request_set_tfm(ahreq, auth); | |
158 | ahash_request_set_crypt(ahreq, req->dst, hash, | |
159 | req->assoclen + req->cryptlen); | |
160 | ahash_request_set_callback(ahreq, flags, | |
161 | authenc_geniv_ahash_done, req); | |
162 | ||
163 | err = crypto_ahash_digest(ahreq); | |
164 | if (err) | |
165 | return err; | |
166 | ||
167 | scatterwalk_map_and_copy(hash, req->dst, req->assoclen + req->cryptlen, | |
168 | crypto_aead_authsize(authenc), 1); | |
169 | ||
170 | return 0; | |
171 | } | |
172 | ||
173 | static void crypto_authenc_encrypt_done(struct crypto_async_request *req, | |
174 | int err) | |
175 | { | |
176 | struct aead_request *areq = req->data; | |
177 | ||
178 | if (err) | |
179 | goto out; | |
180 | ||
181 | err = crypto_authenc_genicv(areq, 0); | |
182 | ||
183 | out: | |
184 | authenc_request_complete(areq, err); | |
185 | } | |
186 | ||
187 | static int crypto_authenc_copy_assoc(struct aead_request *req) | |
188 | { | |
189 | struct crypto_aead *authenc = crypto_aead_reqtfm(req); | |
190 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); | |
191 | SYNC_SKCIPHER_REQUEST_ON_STACK(skreq, ctx->null); | |
192 | ||
193 | skcipher_request_set_sync_tfm(skreq, ctx->null); | |
194 | skcipher_request_set_callback(skreq, aead_request_flags(req), | |
195 | NULL, NULL); | |
196 | skcipher_request_set_crypt(skreq, req->src, req->dst, req->assoclen, | |
197 | NULL); | |
198 | ||
199 | return crypto_skcipher_encrypt(skreq); | |
200 | } | |
201 | ||
202 | static int crypto_authenc_encrypt(struct aead_request *req) | |
203 | { | |
204 | struct crypto_aead *authenc = crypto_aead_reqtfm(req); | |
205 | struct aead_instance *inst = aead_alg_instance(authenc); | |
206 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); | |
207 | struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); | |
208 | struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); | |
209 | struct crypto_skcipher *enc = ctx->enc; | |
210 | unsigned int cryptlen = req->cryptlen; | |
211 | struct skcipher_request *skreq = (void *)(areq_ctx->tail + | |
212 | ictx->reqoff); | |
213 | struct scatterlist *src, *dst; | |
214 | int err; | |
215 | ||
216 | src = scatterwalk_ffwd(areq_ctx->src, req->src, req->assoclen); | |
217 | dst = src; | |
218 | ||
219 | if (req->src != req->dst) { | |
220 | err = crypto_authenc_copy_assoc(req); | |
221 | if (err) | |
222 | return err; | |
223 | ||
224 | dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen); | |
225 | } | |
226 | ||
227 | skcipher_request_set_tfm(skreq, enc); | |
228 | skcipher_request_set_callback(skreq, aead_request_flags(req), | |
229 | crypto_authenc_encrypt_done, req); | |
230 | skcipher_request_set_crypt(skreq, src, dst, cryptlen, req->iv); | |
231 | ||
232 | err = crypto_skcipher_encrypt(skreq); | |
233 | if (err) | |
234 | return err; | |
235 | ||
236 | return crypto_authenc_genicv(req, aead_request_flags(req)); | |
237 | } | |
238 | ||
239 | static int crypto_authenc_decrypt_tail(struct aead_request *req, | |
240 | unsigned int flags) | |
241 | { | |
242 | struct crypto_aead *authenc = crypto_aead_reqtfm(req); | |
243 | struct aead_instance *inst = aead_alg_instance(authenc); | |
244 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); | |
245 | struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); | |
246 | struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); | |
247 | struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); | |
248 | struct skcipher_request *skreq = (void *)(areq_ctx->tail + | |
249 | ictx->reqoff); | |
250 | unsigned int authsize = crypto_aead_authsize(authenc); | |
251 | u8 *ihash = ahreq->result + authsize; | |
252 | struct scatterlist *src, *dst; | |
253 | ||
254 | scatterwalk_map_and_copy(ihash, req->src, ahreq->nbytes, authsize, 0); | |
255 | ||
256 | if (crypto_memneq(ihash, ahreq->result, authsize)) | |
257 | return -EBADMSG; | |
258 | ||
259 | src = scatterwalk_ffwd(areq_ctx->src, req->src, req->assoclen); | |
260 | dst = src; | |
261 | ||
262 | if (req->src != req->dst) | |
263 | dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen); | |
264 | ||
265 | skcipher_request_set_tfm(skreq, ctx->enc); | |
266 | skcipher_request_set_callback(skreq, aead_request_flags(req), | |
267 | req->base.complete, req->base.data); | |
268 | skcipher_request_set_crypt(skreq, src, dst, | |
269 | req->cryptlen - authsize, req->iv); | |
270 | ||
271 | return crypto_skcipher_decrypt(skreq); | |
272 | } | |
273 | ||
274 | static void authenc_verify_ahash_done(struct crypto_async_request *areq, | |
275 | int err) | |
276 | { | |
277 | struct aead_request *req = areq->data; | |
278 | ||
279 | if (err) | |
280 | goto out; | |
281 | ||
282 | err = crypto_authenc_decrypt_tail(req, 0); | |
283 | ||
284 | out: | |
285 | authenc_request_complete(req, err); | |
286 | } | |
287 | ||
288 | static int crypto_authenc_decrypt(struct aead_request *req) | |
289 | { | |
290 | struct crypto_aead *authenc = crypto_aead_reqtfm(req); | |
291 | unsigned int authsize = crypto_aead_authsize(authenc); | |
292 | struct aead_instance *inst = aead_alg_instance(authenc); | |
293 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); | |
294 | struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); | |
295 | struct crypto_ahash *auth = ctx->auth; | |
296 | struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); | |
297 | struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); | |
298 | u8 *hash = areq_ctx->tail; | |
299 | int err; | |
300 | ||
301 | hash = (u8 *)ALIGN((unsigned long)hash + crypto_ahash_alignmask(auth), | |
302 | crypto_ahash_alignmask(auth) + 1); | |
303 | ||
304 | ahash_request_set_tfm(ahreq, auth); | |
305 | ahash_request_set_crypt(ahreq, req->src, hash, | |
306 | req->assoclen + req->cryptlen - authsize); | |
307 | ahash_request_set_callback(ahreq, aead_request_flags(req), | |
308 | authenc_verify_ahash_done, req); | |
309 | ||
310 | err = crypto_ahash_digest(ahreq); | |
311 | if (err) | |
312 | return err; | |
313 | ||
314 | return crypto_authenc_decrypt_tail(req, aead_request_flags(req)); | |
315 | } | |
316 | ||
317 | static int crypto_authenc_init_tfm(struct crypto_aead *tfm) | |
318 | { | |
319 | struct aead_instance *inst = aead_alg_instance(tfm); | |
320 | struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); | |
321 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm); | |
322 | struct crypto_ahash *auth; | |
323 | struct crypto_skcipher *enc; | |
324 | struct crypto_sync_skcipher *null; | |
325 | int err; | |
326 | ||
327 | auth = crypto_spawn_ahash(&ictx->auth); | |
328 | if (IS_ERR(auth)) | |
329 | return PTR_ERR(auth); | |
330 | ||
331 | enc = crypto_spawn_skcipher(&ictx->enc); | |
332 | err = PTR_ERR(enc); | |
333 | if (IS_ERR(enc)) | |
334 | goto err_free_ahash; | |
335 | ||
336 | null = crypto_get_default_null_skcipher(); | |
337 | err = PTR_ERR(null); | |
338 | if (IS_ERR(null)) | |
339 | goto err_free_skcipher; | |
340 | ||
341 | ctx->auth = auth; | |
342 | ctx->enc = enc; | |
343 | ctx->null = null; | |
344 | ||
345 | crypto_aead_set_reqsize( | |
346 | tfm, | |
347 | sizeof(struct authenc_request_ctx) + | |
348 | ictx->reqoff + | |
349 | max_t(unsigned int, | |
350 | crypto_ahash_reqsize(auth) + | |
351 | sizeof(struct ahash_request), | |
352 | sizeof(struct skcipher_request) + | |
353 | crypto_skcipher_reqsize(enc))); | |
354 | ||
355 | return 0; | |
356 | ||
357 | err_free_skcipher: | |
358 | crypto_free_skcipher(enc); | |
359 | err_free_ahash: | |
360 | crypto_free_ahash(auth); | |
361 | return err; | |
362 | } | |
363 | ||
364 | static void crypto_authenc_exit_tfm(struct crypto_aead *tfm) | |
365 | { | |
366 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm); | |
367 | ||
368 | crypto_free_ahash(ctx->auth); | |
369 | crypto_free_skcipher(ctx->enc); | |
370 | crypto_put_default_null_skcipher(); | |
371 | } | |
372 | ||
373 | static void crypto_authenc_free(struct aead_instance *inst) | |
374 | { | |
375 | struct authenc_instance_ctx *ctx = aead_instance_ctx(inst); | |
376 | ||
377 | crypto_drop_skcipher(&ctx->enc); | |
378 | crypto_drop_ahash(&ctx->auth); | |
379 | kfree(inst); | |
380 | } | |
381 | ||
382 | static int crypto_authenc_create(struct crypto_template *tmpl, | |
383 | struct rtattr **tb) | |
384 | { | |
385 | struct crypto_attr_type *algt; | |
386 | struct aead_instance *inst; | |
387 | struct hash_alg_common *auth; | |
388 | struct crypto_alg *auth_base; | |
389 | struct skcipher_alg *enc; | |
390 | struct authenc_instance_ctx *ctx; | |
391 | const char *enc_name; | |
392 | int err; | |
393 | ||
394 | algt = crypto_get_attr_type(tb); | |
395 | if (IS_ERR(algt)) | |
396 | return PTR_ERR(algt); | |
397 | ||
398 | if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask) | |
399 | return -EINVAL; | |
400 | ||
401 | auth = ahash_attr_alg(tb[1], CRYPTO_ALG_TYPE_HASH, | |
402 | CRYPTO_ALG_TYPE_AHASH_MASK | | |
403 | crypto_requires_sync(algt->type, algt->mask)); | |
404 | if (IS_ERR(auth)) | |
405 | return PTR_ERR(auth); | |
406 | ||
407 | auth_base = &auth->base; | |
408 | ||
409 | enc_name = crypto_attr_alg_name(tb[2]); | |
410 | err = PTR_ERR(enc_name); | |
411 | if (IS_ERR(enc_name)) | |
412 | goto out_put_auth; | |
413 | ||
414 | inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL); | |
415 | err = -ENOMEM; | |
416 | if (!inst) | |
417 | goto out_put_auth; | |
418 | ||
419 | ctx = aead_instance_ctx(inst); | |
420 | ||
421 | err = crypto_init_ahash_spawn(&ctx->auth, auth, | |
422 | aead_crypto_instance(inst)); | |
423 | if (err) | |
424 | goto err_free_inst; | |
425 | ||
426 | crypto_set_skcipher_spawn(&ctx->enc, aead_crypto_instance(inst)); | |
427 | err = crypto_grab_skcipher(&ctx->enc, enc_name, 0, | |
428 | crypto_requires_sync(algt->type, | |
429 | algt->mask)); | |
430 | if (err) | |
431 | goto err_drop_auth; | |
432 | ||
433 | enc = crypto_spawn_skcipher_alg(&ctx->enc); | |
434 | ||
435 | ctx->reqoff = ALIGN(2 * auth->digestsize + auth_base->cra_alignmask, | |
436 | auth_base->cra_alignmask + 1); | |
437 | ||
438 | err = -ENAMETOOLONG; | |
439 | if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME, | |
440 | "authenc(%s,%s)", auth_base->cra_name, | |
441 | enc->base.cra_name) >= | |
442 | CRYPTO_MAX_ALG_NAME) | |
443 | goto err_drop_enc; | |
444 | ||
445 | if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME, | |
446 | "authenc(%s,%s)", auth_base->cra_driver_name, | |
447 | enc->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME) | |
448 | goto err_drop_enc; | |
449 | ||
450 | inst->alg.base.cra_flags = (auth_base->cra_flags | | |
451 | enc->base.cra_flags) & CRYPTO_ALG_ASYNC; | |
452 | inst->alg.base.cra_priority = enc->base.cra_priority * 10 + | |
453 | auth_base->cra_priority; | |
454 | inst->alg.base.cra_blocksize = enc->base.cra_blocksize; | |
455 | inst->alg.base.cra_alignmask = auth_base->cra_alignmask | | |
456 | enc->base.cra_alignmask; | |
457 | inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_ctx); | |
458 | ||
459 | inst->alg.ivsize = crypto_skcipher_alg_ivsize(enc); | |
460 | inst->alg.chunksize = crypto_skcipher_alg_chunksize(enc); | |
461 | inst->alg.maxauthsize = auth->digestsize; | |
462 | ||
463 | inst->alg.init = crypto_authenc_init_tfm; | |
464 | inst->alg.exit = crypto_authenc_exit_tfm; | |
465 | ||
466 | inst->alg.setkey = crypto_authenc_setkey; | |
467 | inst->alg.encrypt = crypto_authenc_encrypt; | |
468 | inst->alg.decrypt = crypto_authenc_decrypt; | |
469 | ||
470 | inst->free = crypto_authenc_free; | |
471 | ||
472 | err = aead_register_instance(tmpl, inst); | |
473 | if (err) | |
474 | goto err_drop_enc; | |
475 | ||
476 | out: | |
477 | crypto_mod_put(auth_base); | |
478 | return err; | |
479 | ||
480 | err_drop_enc: | |
481 | crypto_drop_skcipher(&ctx->enc); | |
482 | err_drop_auth: | |
483 | crypto_drop_ahash(&ctx->auth); | |
484 | err_free_inst: | |
485 | kfree(inst); | |
486 | out_put_auth: | |
487 | goto out; | |
488 | } | |
489 | ||
490 | static struct crypto_template crypto_authenc_tmpl = { | |
491 | .name = "authenc", | |
492 | .create = crypto_authenc_create, | |
493 | .module = THIS_MODULE, | |
494 | }; | |
495 | ||
496 | static int __init crypto_authenc_module_init(void) | |
497 | { | |
498 | return crypto_register_template(&crypto_authenc_tmpl); | |
499 | } | |
500 | ||
501 | static void __exit crypto_authenc_module_exit(void) | |
502 | { | |
503 | crypto_unregister_template(&crypto_authenc_tmpl); | |
504 | } | |
505 | ||
506 | subsys_initcall(crypto_authenc_module_init); | |
507 | module_exit(crypto_authenc_module_exit); | |
508 | ||
509 | MODULE_LICENSE("GPL"); | |
510 | MODULE_DESCRIPTION("Simple AEAD wrapper for IPsec"); | |
511 | MODULE_ALIAS_CRYPTO("authenc"); |