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1 | // SPDX-License-Identifier: GPL-2.0-or-later | |
2 | /* | |
3 | * authencesn.c - AEAD wrapper for IPsec with extended sequence numbers, | |
4 | * derived from authenc.c | |
5 | * | |
6 | * Copyright (C) 2010 secunet Security Networks AG | |
7 | * Copyright (C) 2010 Steffen Klassert <steffen.klassert@secunet.com> | |
8 | * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au> | |
9 | */ | |
10 | ||
11 | #include <crypto/internal/aead.h> | |
12 | #include <crypto/internal/hash.h> | |
13 | #include <crypto/internal/skcipher.h> | |
14 | #include <crypto/authenc.h> | |
15 | #include <crypto/null.h> | |
16 | #include <crypto/scatterwalk.h> | |
17 | #include <linux/err.h> | |
18 | #include <linux/init.h> | |
19 | #include <linux/kernel.h> | |
20 | #include <linux/module.h> | |
21 | #include <linux/rtnetlink.h> | |
22 | #include <linux/slab.h> | |
23 | #include <linux/spinlock.h> | |
24 | ||
25 | struct authenc_esn_instance_ctx { | |
26 | struct crypto_ahash_spawn auth; | |
27 | struct crypto_skcipher_spawn enc; | |
28 | }; | |
29 | ||
30 | struct crypto_authenc_esn_ctx { | |
31 | unsigned int reqoff; | |
32 | struct crypto_ahash *auth; | |
33 | struct crypto_skcipher *enc; | |
34 | struct crypto_sync_skcipher *null; | |
35 | }; | |
36 | ||
37 | struct authenc_esn_request_ctx { | |
38 | struct scatterlist src[2]; | |
39 | struct scatterlist dst[2]; | |
40 | char tail[]; | |
41 | }; | |
42 | ||
43 | static void authenc_esn_request_complete(struct aead_request *req, int err) | |
44 | { | |
45 | if (err != -EINPROGRESS) | |
46 | aead_request_complete(req, err); | |
47 | } | |
48 | ||
49 | static int crypto_authenc_esn_setauthsize(struct crypto_aead *authenc_esn, | |
50 | unsigned int authsize) | |
51 | { | |
52 | if (authsize > 0 && authsize < 4) | |
53 | return -EINVAL; | |
54 | ||
55 | return 0; | |
56 | } | |
57 | ||
58 | static int crypto_authenc_esn_setkey(struct crypto_aead *authenc_esn, const u8 *key, | |
59 | unsigned int keylen) | |
60 | { | |
61 | struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn); | |
62 | struct crypto_ahash *auth = ctx->auth; | |
63 | struct crypto_skcipher *enc = ctx->enc; | |
64 | struct crypto_authenc_keys keys; | |
65 | int err = -EINVAL; | |
66 | ||
67 | if (crypto_authenc_extractkeys(&keys, key, keylen) != 0) | |
68 | goto out; | |
69 | ||
70 | crypto_ahash_clear_flags(auth, CRYPTO_TFM_REQ_MASK); | |
71 | crypto_ahash_set_flags(auth, crypto_aead_get_flags(authenc_esn) & | |
72 | CRYPTO_TFM_REQ_MASK); | |
73 | err = crypto_ahash_setkey(auth, keys.authkey, keys.authkeylen); | |
74 | if (err) | |
75 | goto out; | |
76 | ||
77 | crypto_skcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK); | |
78 | crypto_skcipher_set_flags(enc, crypto_aead_get_flags(authenc_esn) & | |
79 | CRYPTO_TFM_REQ_MASK); | |
80 | err = crypto_skcipher_setkey(enc, keys.enckey, keys.enckeylen); | |
81 | out: | |
82 | memzero_explicit(&keys, sizeof(keys)); | |
83 | return err; | |
84 | } | |
85 | ||
86 | static int crypto_authenc_esn_genicv_tail(struct aead_request *req, | |
87 | unsigned int flags) | |
88 | { | |
89 | struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req); | |
90 | struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn); | |
91 | struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req); | |
92 | struct crypto_ahash *auth = ctx->auth; | |
93 | u8 *hash = PTR_ALIGN((u8 *)areq_ctx->tail, | |
94 | crypto_ahash_alignmask(auth) + 1); | |
95 | unsigned int authsize = crypto_aead_authsize(authenc_esn); | |
96 | unsigned int assoclen = req->assoclen; | |
97 | unsigned int cryptlen = req->cryptlen; | |
98 | struct scatterlist *dst = req->dst; | |
99 | u32 tmp[2]; | |
100 | ||
101 | /* Move high-order bits of sequence number back. */ | |
102 | scatterwalk_map_and_copy(tmp, dst, 4, 4, 0); | |
103 | scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 0); | |
104 | scatterwalk_map_and_copy(tmp, dst, 0, 8, 1); | |
105 | ||
106 | scatterwalk_map_and_copy(hash, dst, assoclen + cryptlen, authsize, 1); | |
107 | return 0; | |
108 | } | |
109 | ||
110 | static void authenc_esn_geniv_ahash_done(struct crypto_async_request *areq, | |
111 | int err) | |
112 | { | |
113 | struct aead_request *req = areq->data; | |
114 | ||
115 | err = err ?: crypto_authenc_esn_genicv_tail(req, 0); | |
116 | aead_request_complete(req, err); | |
117 | } | |
118 | ||
119 | static int crypto_authenc_esn_genicv(struct aead_request *req, | |
120 | unsigned int flags) | |
121 | { | |
122 | struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req); | |
123 | struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req); | |
124 | struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn); | |
125 | struct crypto_ahash *auth = ctx->auth; | |
126 | u8 *hash = PTR_ALIGN((u8 *)areq_ctx->tail, | |
127 | crypto_ahash_alignmask(auth) + 1); | |
128 | struct ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff); | |
129 | unsigned int authsize = crypto_aead_authsize(authenc_esn); | |
130 | unsigned int assoclen = req->assoclen; | |
131 | unsigned int cryptlen = req->cryptlen; | |
132 | struct scatterlist *dst = req->dst; | |
133 | u32 tmp[2]; | |
134 | ||
135 | if (!authsize) | |
136 | return 0; | |
137 | ||
138 | /* Move high-order bits of sequence number to the end. */ | |
139 | scatterwalk_map_and_copy(tmp, dst, 0, 8, 0); | |
140 | scatterwalk_map_and_copy(tmp, dst, 4, 4, 1); | |
141 | scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 1); | |
142 | ||
143 | sg_init_table(areq_ctx->dst, 2); | |
144 | dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4); | |
145 | ||
146 | ahash_request_set_tfm(ahreq, auth); | |
147 | ahash_request_set_crypt(ahreq, dst, hash, assoclen + cryptlen); | |
148 | ahash_request_set_callback(ahreq, flags, | |
149 | authenc_esn_geniv_ahash_done, req); | |
150 | ||
151 | return crypto_ahash_digest(ahreq) ?: | |
152 | crypto_authenc_esn_genicv_tail(req, aead_request_flags(req)); | |
153 | } | |
154 | ||
155 | ||
156 | static void crypto_authenc_esn_encrypt_done(struct crypto_async_request *req, | |
157 | int err) | |
158 | { | |
159 | struct aead_request *areq = req->data; | |
160 | ||
161 | if (!err) | |
162 | err = crypto_authenc_esn_genicv(areq, 0); | |
163 | ||
164 | authenc_esn_request_complete(areq, err); | |
165 | } | |
166 | ||
167 | static int crypto_authenc_esn_copy(struct aead_request *req, unsigned int len) | |
168 | { | |
169 | struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req); | |
170 | struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn); | |
171 | SYNC_SKCIPHER_REQUEST_ON_STACK(skreq, ctx->null); | |
172 | ||
173 | skcipher_request_set_sync_tfm(skreq, ctx->null); | |
174 | skcipher_request_set_callback(skreq, aead_request_flags(req), | |
175 | NULL, NULL); | |
176 | skcipher_request_set_crypt(skreq, req->src, req->dst, len, NULL); | |
177 | ||
178 | return crypto_skcipher_encrypt(skreq); | |
179 | } | |
180 | ||
181 | static int crypto_authenc_esn_encrypt(struct aead_request *req) | |
182 | { | |
183 | struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req); | |
184 | struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req); | |
185 | struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn); | |
186 | struct skcipher_request *skreq = (void *)(areq_ctx->tail + | |
187 | ctx->reqoff); | |
188 | struct crypto_skcipher *enc = ctx->enc; | |
189 | unsigned int assoclen = req->assoclen; | |
190 | unsigned int cryptlen = req->cryptlen; | |
191 | struct scatterlist *src, *dst; | |
192 | int err; | |
193 | ||
194 | sg_init_table(areq_ctx->src, 2); | |
195 | src = scatterwalk_ffwd(areq_ctx->src, req->src, assoclen); | |
196 | dst = src; | |
197 | ||
198 | if (req->src != req->dst) { | |
199 | err = crypto_authenc_esn_copy(req, assoclen); | |
200 | if (err) | |
201 | return err; | |
202 | ||
203 | sg_init_table(areq_ctx->dst, 2); | |
204 | dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, assoclen); | |
205 | } | |
206 | ||
207 | skcipher_request_set_tfm(skreq, enc); | |
208 | skcipher_request_set_callback(skreq, aead_request_flags(req), | |
209 | crypto_authenc_esn_encrypt_done, req); | |
210 | skcipher_request_set_crypt(skreq, src, dst, cryptlen, req->iv); | |
211 | ||
212 | err = crypto_skcipher_encrypt(skreq); | |
213 | if (err) | |
214 | return err; | |
215 | ||
216 | return crypto_authenc_esn_genicv(req, aead_request_flags(req)); | |
217 | } | |
218 | ||
219 | static int crypto_authenc_esn_decrypt_tail(struct aead_request *req, | |
220 | unsigned int flags) | |
221 | { | |
222 | struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req); | |
223 | unsigned int authsize = crypto_aead_authsize(authenc_esn); | |
224 | struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req); | |
225 | struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn); | |
226 | struct skcipher_request *skreq = (void *)(areq_ctx->tail + | |
227 | ctx->reqoff); | |
228 | struct crypto_ahash *auth = ctx->auth; | |
229 | u8 *ohash = PTR_ALIGN((u8 *)areq_ctx->tail, | |
230 | crypto_ahash_alignmask(auth) + 1); | |
231 | unsigned int cryptlen = req->cryptlen - authsize; | |
232 | unsigned int assoclen = req->assoclen; | |
233 | struct scatterlist *dst = req->dst; | |
234 | u8 *ihash = ohash + crypto_ahash_digestsize(auth); | |
235 | u32 tmp[2]; | |
236 | ||
237 | if (!authsize) | |
238 | goto decrypt; | |
239 | ||
240 | /* Move high-order bits of sequence number back. */ | |
241 | scatterwalk_map_and_copy(tmp, dst, 4, 4, 0); | |
242 | scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 0); | |
243 | scatterwalk_map_and_copy(tmp, dst, 0, 8, 1); | |
244 | ||
245 | if (crypto_memneq(ihash, ohash, authsize)) | |
246 | return -EBADMSG; | |
247 | ||
248 | decrypt: | |
249 | ||
250 | sg_init_table(areq_ctx->dst, 2); | |
251 | dst = scatterwalk_ffwd(areq_ctx->dst, dst, assoclen); | |
252 | ||
253 | skcipher_request_set_tfm(skreq, ctx->enc); | |
254 | skcipher_request_set_callback(skreq, flags, | |
255 | req->base.complete, req->base.data); | |
256 | skcipher_request_set_crypt(skreq, dst, dst, cryptlen, req->iv); | |
257 | ||
258 | return crypto_skcipher_decrypt(skreq); | |
259 | } | |
260 | ||
261 | static void authenc_esn_verify_ahash_done(struct crypto_async_request *areq, | |
262 | int err) | |
263 | { | |
264 | struct aead_request *req = areq->data; | |
265 | ||
266 | err = err ?: crypto_authenc_esn_decrypt_tail(req, 0); | |
267 | authenc_esn_request_complete(req, err); | |
268 | } | |
269 | ||
270 | static int crypto_authenc_esn_decrypt(struct aead_request *req) | |
271 | { | |
272 | struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req); | |
273 | struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req); | |
274 | struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn); | |
275 | struct ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff); | |
276 | unsigned int authsize = crypto_aead_authsize(authenc_esn); | |
277 | struct crypto_ahash *auth = ctx->auth; | |
278 | u8 *ohash = PTR_ALIGN((u8 *)areq_ctx->tail, | |
279 | crypto_ahash_alignmask(auth) + 1); | |
280 | unsigned int assoclen = req->assoclen; | |
281 | unsigned int cryptlen = req->cryptlen; | |
282 | u8 *ihash = ohash + crypto_ahash_digestsize(auth); | |
283 | struct scatterlist *dst = req->dst; | |
284 | u32 tmp[2]; | |
285 | int err; | |
286 | ||
287 | cryptlen -= authsize; | |
288 | ||
289 | if (req->src != dst) { | |
290 | err = crypto_authenc_esn_copy(req, assoclen + cryptlen); | |
291 | if (err) | |
292 | return err; | |
293 | } | |
294 | ||
295 | scatterwalk_map_and_copy(ihash, req->src, assoclen + cryptlen, | |
296 | authsize, 0); | |
297 | ||
298 | if (!authsize) | |
299 | goto tail; | |
300 | ||
301 | /* Move high-order bits of sequence number to the end. */ | |
302 | scatterwalk_map_and_copy(tmp, dst, 0, 8, 0); | |
303 | scatterwalk_map_and_copy(tmp, dst, 4, 4, 1); | |
304 | scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 1); | |
305 | ||
306 | sg_init_table(areq_ctx->dst, 2); | |
307 | dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4); | |
308 | ||
309 | ahash_request_set_tfm(ahreq, auth); | |
310 | ahash_request_set_crypt(ahreq, dst, ohash, assoclen + cryptlen); | |
311 | ahash_request_set_callback(ahreq, aead_request_flags(req), | |
312 | authenc_esn_verify_ahash_done, req); | |
313 | ||
314 | err = crypto_ahash_digest(ahreq); | |
315 | if (err) | |
316 | return err; | |
317 | ||
318 | tail: | |
319 | return crypto_authenc_esn_decrypt_tail(req, aead_request_flags(req)); | |
320 | } | |
321 | ||
322 | static int crypto_authenc_esn_init_tfm(struct crypto_aead *tfm) | |
323 | { | |
324 | struct aead_instance *inst = aead_alg_instance(tfm); | |
325 | struct authenc_esn_instance_ctx *ictx = aead_instance_ctx(inst); | |
326 | struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm); | |
327 | struct crypto_ahash *auth; | |
328 | struct crypto_skcipher *enc; | |
329 | struct crypto_sync_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_skcipher(); | |
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 | ctx->reqoff = ALIGN(2 * crypto_ahash_digestsize(auth), | |
351 | crypto_ahash_alignmask(auth) + 1); | |
352 | ||
353 | crypto_aead_set_reqsize( | |
354 | tfm, | |
355 | sizeof(struct authenc_esn_request_ctx) + | |
356 | ctx->reqoff + | |
357 | max_t(unsigned int, | |
358 | crypto_ahash_reqsize(auth) + | |
359 | sizeof(struct ahash_request), | |
360 | sizeof(struct skcipher_request) + | |
361 | crypto_skcipher_reqsize(enc))); | |
362 | ||
363 | return 0; | |
364 | ||
365 | err_free_skcipher: | |
366 | crypto_free_skcipher(enc); | |
367 | err_free_ahash: | |
368 | crypto_free_ahash(auth); | |
369 | return err; | |
370 | } | |
371 | ||
372 | static void crypto_authenc_esn_exit_tfm(struct crypto_aead *tfm) | |
373 | { | |
374 | struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm); | |
375 | ||
376 | crypto_free_ahash(ctx->auth); | |
377 | crypto_free_skcipher(ctx->enc); | |
378 | crypto_put_default_null_skcipher(); | |
379 | } | |
380 | ||
381 | static void crypto_authenc_esn_free(struct aead_instance *inst) | |
382 | { | |
383 | struct authenc_esn_instance_ctx *ctx = aead_instance_ctx(inst); | |
384 | ||
385 | crypto_drop_skcipher(&ctx->enc); | |
386 | crypto_drop_ahash(&ctx->auth); | |
387 | kfree(inst); | |
388 | } | |
389 | ||
390 | static int crypto_authenc_esn_create(struct crypto_template *tmpl, | |
391 | struct rtattr **tb) | |
392 | { | |
393 | struct crypto_attr_type *algt; | |
394 | u32 mask; | |
395 | struct aead_instance *inst; | |
396 | struct authenc_esn_instance_ctx *ctx; | |
397 | struct hash_alg_common *auth; | |
398 | struct crypto_alg *auth_base; | |
399 | struct skcipher_alg *enc; | |
400 | int err; | |
401 | ||
402 | algt = crypto_get_attr_type(tb); | |
403 | if (IS_ERR(algt)) | |
404 | return PTR_ERR(algt); | |
405 | ||
406 | if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask) | |
407 | return -EINVAL; | |
408 | ||
409 | mask = crypto_requires_sync(algt->type, algt->mask); | |
410 | ||
411 | inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL); | |
412 | if (!inst) | |
413 | return -ENOMEM; | |
414 | ctx = aead_instance_ctx(inst); | |
415 | ||
416 | err = crypto_grab_ahash(&ctx->auth, aead_crypto_instance(inst), | |
417 | crypto_attr_alg_name(tb[1]), 0, mask); | |
418 | if (err) | |
419 | goto err_free_inst; | |
420 | auth = crypto_spawn_ahash_alg(&ctx->auth); | |
421 | auth_base = &auth->base; | |
422 | ||
423 | err = crypto_grab_skcipher(&ctx->enc, aead_crypto_instance(inst), | |
424 | crypto_attr_alg_name(tb[2]), 0, mask); | |
425 | if (err) | |
426 | goto err_free_inst; | |
427 | enc = crypto_spawn_skcipher_alg(&ctx->enc); | |
428 | ||
429 | err = -ENAMETOOLONG; | |
430 | if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME, | |
431 | "authencesn(%s,%s)", auth_base->cra_name, | |
432 | enc->base.cra_name) >= CRYPTO_MAX_ALG_NAME) | |
433 | goto err_free_inst; | |
434 | ||
435 | if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME, | |
436 | "authencesn(%s,%s)", auth_base->cra_driver_name, | |
437 | enc->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME) | |
438 | goto err_free_inst; | |
439 | ||
440 | inst->alg.base.cra_flags = (auth_base->cra_flags | | |
441 | enc->base.cra_flags) & CRYPTO_ALG_ASYNC; | |
442 | inst->alg.base.cra_priority = enc->base.cra_priority * 10 + | |
443 | auth_base->cra_priority; | |
444 | inst->alg.base.cra_blocksize = enc->base.cra_blocksize; | |
445 | inst->alg.base.cra_alignmask = auth_base->cra_alignmask | | |
446 | enc->base.cra_alignmask; | |
447 | inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_esn_ctx); | |
448 | ||
449 | inst->alg.ivsize = crypto_skcipher_alg_ivsize(enc); | |
450 | inst->alg.chunksize = crypto_skcipher_alg_chunksize(enc); | |
451 | inst->alg.maxauthsize = auth->digestsize; | |
452 | ||
453 | inst->alg.init = crypto_authenc_esn_init_tfm; | |
454 | inst->alg.exit = crypto_authenc_esn_exit_tfm; | |
455 | ||
456 | inst->alg.setkey = crypto_authenc_esn_setkey; | |
457 | inst->alg.setauthsize = crypto_authenc_esn_setauthsize; | |
458 | inst->alg.encrypt = crypto_authenc_esn_encrypt; | |
459 | inst->alg.decrypt = crypto_authenc_esn_decrypt; | |
460 | ||
461 | inst->free = crypto_authenc_esn_free, | |
462 | ||
463 | err = aead_register_instance(tmpl, inst); | |
464 | if (err) { | |
465 | err_free_inst: | |
466 | crypto_authenc_esn_free(inst); | |
467 | } | |
468 | return err; | |
469 | } | |
470 | ||
471 | static struct crypto_template crypto_authenc_esn_tmpl = { | |
472 | .name = "authencesn", | |
473 | .create = crypto_authenc_esn_create, | |
474 | .module = THIS_MODULE, | |
475 | }; | |
476 | ||
477 | static int __init crypto_authenc_esn_module_init(void) | |
478 | { | |
479 | return crypto_register_template(&crypto_authenc_esn_tmpl); | |
480 | } | |
481 | ||
482 | static void __exit crypto_authenc_esn_module_exit(void) | |
483 | { | |
484 | crypto_unregister_template(&crypto_authenc_esn_tmpl); | |
485 | } | |
486 | ||
487 | subsys_initcall(crypto_authenc_esn_module_init); | |
488 | module_exit(crypto_authenc_esn_module_exit); | |
489 | ||
490 | MODULE_LICENSE("GPL"); | |
491 | MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>"); | |
492 | MODULE_DESCRIPTION("AEAD wrapper for IPsec with extended sequence numbers"); | |
493 | MODULE_ALIAS_CRYPTO("authencesn"); |