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