blob: 6bfec690ca5be2ef77b7913063fa8b57257d16b3
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_skcipher2(&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_skcipher2(&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"); |
517 |