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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 | ||
62 | /* | |
63 | * RTA_OK() didn't align the rtattr's payload when validating that it | |
64 | * fits in the buffer. Yet, the keys should start on the next 4-byte | |
65 | * aligned boundary. To avoid confusion, require that the rtattr | |
66 | * payload be exactly the param struct, which has a 4-byte aligned size. | |
67 | */ | |
68 | if (RTA_PAYLOAD(rta) != sizeof(*param)) | |
69 | return -EINVAL; | |
70 | BUILD_BUG_ON(sizeof(*param) % RTA_ALIGNTO); | |
71 | ||
72 | param = RTA_DATA(rta); | |
73 | keys->enckeylen = be32_to_cpu(param->enckeylen); | |
74 | ||
75 | key += rta->rta_len; | |
76 | keylen -= rta->rta_len; | |
77 | ||
78 | if (keylen < keys->enckeylen) | |
79 | return -EINVAL; | |
80 | ||
81 | keys->authkeylen = keylen - keys->enckeylen; | |
82 | keys->authkey = key; | |
83 | keys->enckey = key + keys->authkeylen; | |
84 | ||
85 | return 0; | |
86 | } | |
87 | EXPORT_SYMBOL_GPL(crypto_authenc_extractkeys); | |
88 | ||
89 | static int crypto_authenc_setkey(struct crypto_aead *authenc, const u8 *key, | |
90 | unsigned int keylen) | |
91 | { | |
92 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); | |
93 | struct crypto_ahash *auth = ctx->auth; | |
94 | struct crypto_skcipher *enc = ctx->enc; | |
95 | struct crypto_authenc_keys keys; | |
96 | int err = -EINVAL; | |
97 | ||
98 | if (crypto_authenc_extractkeys(&keys, key, keylen) != 0) | |
99 | goto badkey; | |
100 | ||
101 | crypto_ahash_clear_flags(auth, CRYPTO_TFM_REQ_MASK); | |
102 | crypto_ahash_set_flags(auth, crypto_aead_get_flags(authenc) & | |
103 | CRYPTO_TFM_REQ_MASK); | |
104 | err = crypto_ahash_setkey(auth, keys.authkey, keys.authkeylen); | |
105 | crypto_aead_set_flags(authenc, crypto_ahash_get_flags(auth) & | |
106 | CRYPTO_TFM_RES_MASK); | |
107 | ||
108 | if (err) | |
109 | goto out; | |
110 | ||
111 | crypto_skcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK); | |
112 | crypto_skcipher_set_flags(enc, crypto_aead_get_flags(authenc) & | |
113 | CRYPTO_TFM_REQ_MASK); | |
114 | err = crypto_skcipher_setkey(enc, keys.enckey, keys.enckeylen); | |
115 | crypto_aead_set_flags(authenc, crypto_skcipher_get_flags(enc) & | |
116 | CRYPTO_TFM_RES_MASK); | |
117 | ||
118 | out: | |
119 | memzero_explicit(&keys, sizeof(keys)); | |
120 | return err; | |
121 | ||
122 | badkey: | |
123 | crypto_aead_set_flags(authenc, CRYPTO_TFM_RES_BAD_KEY_LEN); | |
124 | goto out; | |
125 | } | |
126 | ||
127 | static void authenc_geniv_ahash_done(struct crypto_async_request *areq, int err) | |
128 | { | |
129 | struct aead_request *req = areq->data; | |
130 | struct crypto_aead *authenc = crypto_aead_reqtfm(req); | |
131 | struct aead_instance *inst = aead_alg_instance(authenc); | |
132 | struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); | |
133 | struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); | |
134 | struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); | |
135 | ||
136 | if (err) | |
137 | goto out; | |
138 | ||
139 | scatterwalk_map_and_copy(ahreq->result, req->dst, | |
140 | req->assoclen + req->cryptlen, | |
141 | crypto_aead_authsize(authenc), 1); | |
142 | ||
143 | out: | |
144 | aead_request_complete(req, err); | |
145 | } | |
146 | ||
147 | static int crypto_authenc_genicv(struct aead_request *req, unsigned int flags) | |
148 | { | |
149 | struct crypto_aead *authenc = crypto_aead_reqtfm(req); | |
150 | struct aead_instance *inst = aead_alg_instance(authenc); | |
151 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); | |
152 | struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); | |
153 | struct crypto_ahash *auth = ctx->auth; | |
154 | struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); | |
155 | struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); | |
156 | u8 *hash = areq_ctx->tail; | |
157 | int err; | |
158 | ||
159 | hash = (u8 *)ALIGN((unsigned long)hash + crypto_ahash_alignmask(auth), | |
160 | crypto_ahash_alignmask(auth) + 1); | |
161 | ||
162 | ahash_request_set_tfm(ahreq, auth); | |
163 | ahash_request_set_crypt(ahreq, req->dst, hash, | |
164 | req->assoclen + req->cryptlen); | |
165 | ahash_request_set_callback(ahreq, flags, | |
166 | authenc_geniv_ahash_done, req); | |
167 | ||
168 | err = crypto_ahash_digest(ahreq); | |
169 | if (err) | |
170 | return err; | |
171 | ||
172 | scatterwalk_map_and_copy(hash, req->dst, req->assoclen + req->cryptlen, | |
173 | crypto_aead_authsize(authenc), 1); | |
174 | ||
175 | return 0; | |
176 | } | |
177 | ||
178 | static void crypto_authenc_encrypt_done(struct crypto_async_request *req, | |
179 | int err) | |
180 | { | |
181 | struct aead_request *areq = req->data; | |
182 | ||
183 | if (err) | |
184 | goto out; | |
185 | ||
186 | err = crypto_authenc_genicv(areq, 0); | |
187 | ||
188 | out: | |
189 | authenc_request_complete(areq, err); | |
190 | } | |
191 | ||
192 | static int crypto_authenc_copy_assoc(struct aead_request *req) | |
193 | { | |
194 | struct crypto_aead *authenc = crypto_aead_reqtfm(req); | |
195 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); | |
196 | SKCIPHER_REQUEST_ON_STACK(skreq, ctx->null); | |
197 | ||
198 | skcipher_request_set_tfm(skreq, ctx->null); | |
199 | skcipher_request_set_callback(skreq, aead_request_flags(req), | |
200 | NULL, NULL); | |
201 | skcipher_request_set_crypt(skreq, req->src, req->dst, req->assoclen, | |
202 | NULL); | |
203 | ||
204 | return crypto_skcipher_encrypt(skreq); | |
205 | } | |
206 | ||
207 | static int crypto_authenc_encrypt(struct aead_request *req) | |
208 | { | |
209 | struct crypto_aead *authenc = crypto_aead_reqtfm(req); | |
210 | struct aead_instance *inst = aead_alg_instance(authenc); | |
211 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); | |
212 | struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); | |
213 | struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); | |
214 | struct crypto_skcipher *enc = ctx->enc; | |
215 | unsigned int cryptlen = req->cryptlen; | |
216 | struct skcipher_request *skreq = (void *)(areq_ctx->tail + | |
217 | ictx->reqoff); | |
218 | struct scatterlist *src, *dst; | |
219 | int err; | |
220 | ||
221 | src = scatterwalk_ffwd(areq_ctx->src, req->src, req->assoclen); | |
222 | dst = src; | |
223 | ||
224 | if (req->src != req->dst) { | |
225 | err = crypto_authenc_copy_assoc(req); | |
226 | if (err) | |
227 | return err; | |
228 | ||
229 | dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen); | |
230 | } | |
231 | ||
232 | skcipher_request_set_tfm(skreq, enc); | |
233 | skcipher_request_set_callback(skreq, aead_request_flags(req), | |
234 | crypto_authenc_encrypt_done, req); | |
235 | skcipher_request_set_crypt(skreq, src, dst, cryptlen, req->iv); | |
236 | ||
237 | err = crypto_skcipher_encrypt(skreq); | |
238 | if (err) | |
239 | return err; | |
240 | ||
241 | return crypto_authenc_genicv(req, aead_request_flags(req)); | |
242 | } | |
243 | ||
244 | static int crypto_authenc_decrypt_tail(struct aead_request *req, | |
245 | unsigned int flags) | |
246 | { | |
247 | struct crypto_aead *authenc = crypto_aead_reqtfm(req); | |
248 | struct aead_instance *inst = aead_alg_instance(authenc); | |
249 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); | |
250 | struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); | |
251 | struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); | |
252 | struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); | |
253 | struct skcipher_request *skreq = (void *)(areq_ctx->tail + | |
254 | ictx->reqoff); | |
255 | unsigned int authsize = crypto_aead_authsize(authenc); | |
256 | u8 *ihash = ahreq->result + authsize; | |
257 | struct scatterlist *src, *dst; | |
258 | ||
259 | scatterwalk_map_and_copy(ihash, req->src, ahreq->nbytes, authsize, 0); | |
260 | ||
261 | if (crypto_memneq(ihash, ahreq->result, authsize)) | |
262 | return -EBADMSG; | |
263 | ||
264 | src = scatterwalk_ffwd(areq_ctx->src, req->src, req->assoclen); | |
265 | dst = src; | |
266 | ||
267 | if (req->src != req->dst) | |
268 | dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen); | |
269 | ||
270 | skcipher_request_set_tfm(skreq, ctx->enc); | |
271 | skcipher_request_set_callback(skreq, aead_request_flags(req), | |
272 | req->base.complete, req->base.data); | |
273 | skcipher_request_set_crypt(skreq, src, dst, | |
274 | req->cryptlen - authsize, req->iv); | |
275 | ||
276 | return crypto_skcipher_decrypt(skreq); | |
277 | } | |
278 | ||
279 | static void authenc_verify_ahash_done(struct crypto_async_request *areq, | |
280 | int err) | |
281 | { | |
282 | struct aead_request *req = areq->data; | |
283 | ||
284 | if (err) | |
285 | goto out; | |
286 | ||
287 | err = crypto_authenc_decrypt_tail(req, 0); | |
288 | ||
289 | out: | |
290 | authenc_request_complete(req, err); | |
291 | } | |
292 | ||
293 | static int crypto_authenc_decrypt(struct aead_request *req) | |
294 | { | |
295 | struct crypto_aead *authenc = crypto_aead_reqtfm(req); | |
296 | unsigned int authsize = crypto_aead_authsize(authenc); | |
297 | struct aead_instance *inst = aead_alg_instance(authenc); | |
298 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); | |
299 | struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); | |
300 | struct crypto_ahash *auth = ctx->auth; | |
301 | struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); | |
302 | struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); | |
303 | u8 *hash = areq_ctx->tail; | |
304 | int err; | |
305 | ||
306 | hash = (u8 *)ALIGN((unsigned long)hash + crypto_ahash_alignmask(auth), | |
307 | crypto_ahash_alignmask(auth) + 1); | |
308 | ||
309 | ahash_request_set_tfm(ahreq, auth); | |
310 | ahash_request_set_crypt(ahreq, req->src, hash, | |
311 | req->assoclen + req->cryptlen - authsize); | |
312 | ahash_request_set_callback(ahreq, aead_request_flags(req), | |
313 | authenc_verify_ahash_done, req); | |
314 | ||
315 | err = crypto_ahash_digest(ahreq); | |
316 | if (err) | |
317 | return err; | |
318 | ||
319 | return crypto_authenc_decrypt_tail(req, aead_request_flags(req)); | |
320 | } | |
321 | ||
322 | static int crypto_authenc_init_tfm(struct crypto_aead *tfm) | |
323 | { | |
324 | struct aead_instance *inst = aead_alg_instance(tfm); | |
325 | struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); | |
326 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm); | |
327 | struct crypto_ahash *auth; | |
328 | struct crypto_skcipher *enc; | |
329 | struct crypto_skcipher *null; | |
330 | int err; | |
331 | ||
332 | auth = crypto_spawn_ahash(&ictx->auth); | |
333 | if (IS_ERR(auth)) | |
334 | return PTR_ERR(auth); | |
335 | ||
336 | enc = crypto_spawn_skcipher(&ictx->enc); | |
337 | err = PTR_ERR(enc); | |
338 | if (IS_ERR(enc)) | |
339 | goto err_free_ahash; | |
340 | ||
341 | null = crypto_get_default_null_skcipher2(); | |
342 | err = PTR_ERR(null); | |
343 | if (IS_ERR(null)) | |
344 | goto err_free_skcipher; | |
345 | ||
346 | ctx->auth = auth; | |
347 | ctx->enc = enc; | |
348 | ctx->null = null; | |
349 | ||
350 | crypto_aead_set_reqsize( | |
351 | tfm, | |
352 | sizeof(struct authenc_request_ctx) + | |
353 | ictx->reqoff + | |
354 | max_t(unsigned int, | |
355 | crypto_ahash_reqsize(auth) + | |
356 | sizeof(struct ahash_request), | |
357 | sizeof(struct skcipher_request) + | |
358 | crypto_skcipher_reqsize(enc))); | |
359 | ||
360 | return 0; | |
361 | ||
362 | err_free_skcipher: | |
363 | crypto_free_skcipher(enc); | |
364 | err_free_ahash: | |
365 | crypto_free_ahash(auth); | |
366 | return err; | |
367 | } | |
368 | ||
369 | static void crypto_authenc_exit_tfm(struct crypto_aead *tfm) | |
370 | { | |
371 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm); | |
372 | ||
373 | crypto_free_ahash(ctx->auth); | |
374 | crypto_free_skcipher(ctx->enc); | |
375 | crypto_put_default_null_skcipher2(); | |
376 | } | |
377 | ||
378 | static void crypto_authenc_free(struct aead_instance *inst) | |
379 | { | |
380 | struct authenc_instance_ctx *ctx = aead_instance_ctx(inst); | |
381 | ||
382 | crypto_drop_skcipher(&ctx->enc); | |
383 | crypto_drop_ahash(&ctx->auth); | |
384 | kfree(inst); | |
385 | } | |
386 | ||
387 | static int crypto_authenc_create(struct crypto_template *tmpl, | |
388 | struct rtattr **tb) | |
389 | { | |
390 | struct crypto_attr_type *algt; | |
391 | struct aead_instance *inst; | |
392 | struct hash_alg_common *auth; | |
393 | struct crypto_alg *auth_base; | |
394 | struct skcipher_alg *enc; | |
395 | struct authenc_instance_ctx *ctx; | |
396 | const char *enc_name; | |
397 | int err; | |
398 | ||
399 | algt = crypto_get_attr_type(tb); | |
400 | if (IS_ERR(algt)) | |
401 | return PTR_ERR(algt); | |
402 | ||
403 | if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask) | |
404 | return -EINVAL; | |
405 | ||
406 | auth = ahash_attr_alg(tb[1], CRYPTO_ALG_TYPE_HASH, | |
407 | CRYPTO_ALG_TYPE_AHASH_MASK | | |
408 | crypto_requires_sync(algt->type, algt->mask)); | |
409 | if (IS_ERR(auth)) | |
410 | return PTR_ERR(auth); | |
411 | ||
412 | auth_base = &auth->base; | |
413 | ||
414 | enc_name = crypto_attr_alg_name(tb[2]); | |
415 | err = PTR_ERR(enc_name); | |
416 | if (IS_ERR(enc_name)) | |
417 | goto out_put_auth; | |
418 | ||
419 | inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL); | |
420 | err = -ENOMEM; | |
421 | if (!inst) | |
422 | goto out_put_auth; | |
423 | ||
424 | ctx = aead_instance_ctx(inst); | |
425 | ||
426 | err = crypto_init_ahash_spawn(&ctx->auth, auth, | |
427 | aead_crypto_instance(inst)); | |
428 | if (err) | |
429 | goto err_free_inst; | |
430 | ||
431 | crypto_set_skcipher_spawn(&ctx->enc, aead_crypto_instance(inst)); | |
432 | err = crypto_grab_skcipher(&ctx->enc, enc_name, 0, | |
433 | crypto_requires_sync(algt->type, | |
434 | algt->mask)); | |
435 | if (err) | |
436 | goto err_drop_auth; | |
437 | ||
438 | enc = crypto_spawn_skcipher_alg(&ctx->enc); | |
439 | ||
440 | ctx->reqoff = ALIGN(2 * auth->digestsize + auth_base->cra_alignmask, | |
441 | auth_base->cra_alignmask + 1); | |
442 | ||
443 | err = -ENAMETOOLONG; | |
444 | if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME, | |
445 | "authenc(%s,%s)", auth_base->cra_name, | |
446 | enc->base.cra_name) >= | |
447 | CRYPTO_MAX_ALG_NAME) | |
448 | goto err_drop_enc; | |
449 | ||
450 | if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME, | |
451 | "authenc(%s,%s)", auth_base->cra_driver_name, | |
452 | enc->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME) | |
453 | goto err_drop_enc; | |
454 | ||
455 | inst->alg.base.cra_flags = (auth_base->cra_flags | | |
456 | enc->base.cra_flags) & CRYPTO_ALG_ASYNC; | |
457 | inst->alg.base.cra_priority = enc->base.cra_priority * 10 + | |
458 | auth_base->cra_priority; | |
459 | inst->alg.base.cra_blocksize = enc->base.cra_blocksize; | |
460 | inst->alg.base.cra_alignmask = auth_base->cra_alignmask | | |
461 | enc->base.cra_alignmask; | |
462 | inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_ctx); | |
463 | ||
464 | inst->alg.ivsize = crypto_skcipher_alg_ivsize(enc); | |
465 | inst->alg.chunksize = crypto_skcipher_alg_chunksize(enc); | |
466 | inst->alg.maxauthsize = auth->digestsize; | |
467 | ||
468 | inst->alg.init = crypto_authenc_init_tfm; | |
469 | inst->alg.exit = crypto_authenc_exit_tfm; | |
470 | ||
471 | inst->alg.setkey = crypto_authenc_setkey; | |
472 | inst->alg.encrypt = crypto_authenc_encrypt; | |
473 | inst->alg.decrypt = crypto_authenc_decrypt; | |
474 | ||
475 | inst->free = crypto_authenc_free; | |
476 | ||
477 | err = aead_register_instance(tmpl, inst); | |
478 | if (err) | |
479 | goto err_drop_enc; | |
480 | ||
481 | out: | |
482 | crypto_mod_put(auth_base); | |
483 | return err; | |
484 | ||
485 | err_drop_enc: | |
486 | crypto_drop_skcipher(&ctx->enc); | |
487 | err_drop_auth: | |
488 | crypto_drop_ahash(&ctx->auth); | |
489 | err_free_inst: | |
490 | kfree(inst); | |
491 | out_put_auth: | |
492 | goto out; | |
493 | } | |
494 | ||
495 | static struct crypto_template crypto_authenc_tmpl = { | |
496 | .name = "authenc", | |
497 | .create = crypto_authenc_create, | |
498 | .module = THIS_MODULE, | |
499 | }; | |
500 | ||
501 | static int __init crypto_authenc_module_init(void) | |
502 | { | |
503 | return crypto_register_template(&crypto_authenc_tmpl); | |
504 | } | |
505 | ||
506 | static void __exit crypto_authenc_module_exit(void) | |
507 | { | |
508 | crypto_unregister_template(&crypto_authenc_tmpl); | |
509 | } | |
510 | ||
511 | module_init(crypto_authenc_module_init); | |
512 | module_exit(crypto_authenc_module_exit); | |
513 | ||
514 | MODULE_LICENSE("GPL"); | |
515 | MODULE_DESCRIPTION("Simple AEAD wrapper for IPsec"); | |
516 | MODULE_ALIAS_CRYPTO("authenc"); |