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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 out; | |
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 | 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 | out: | |
108 | memzero_explicit(&keys, sizeof(keys)); | |
109 | return err; | |
110 | } | |
111 | ||
112 | static void authenc_geniv_ahash_done(struct crypto_async_request *areq, int err) | |
113 | { | |
114 | struct aead_request *req = areq->data; | |
115 | struct crypto_aead *authenc = crypto_aead_reqtfm(req); | |
116 | struct aead_instance *inst = aead_alg_instance(authenc); | |
117 | struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); | |
118 | struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); | |
119 | struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); | |
120 | ||
121 | if (err) | |
122 | goto out; | |
123 | ||
124 | scatterwalk_map_and_copy(ahreq->result, req->dst, | |
125 | req->assoclen + req->cryptlen, | |
126 | crypto_aead_authsize(authenc), 1); | |
127 | ||
128 | out: | |
129 | aead_request_complete(req, err); | |
130 | } | |
131 | ||
132 | static int crypto_authenc_genicv(struct aead_request *req, unsigned int flags) | |
133 | { | |
134 | struct crypto_aead *authenc = crypto_aead_reqtfm(req); | |
135 | struct aead_instance *inst = aead_alg_instance(authenc); | |
136 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); | |
137 | struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); | |
138 | struct crypto_ahash *auth = ctx->auth; | |
139 | struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); | |
140 | struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); | |
141 | u8 *hash = areq_ctx->tail; | |
142 | int err; | |
143 | ||
144 | hash = (u8 *)ALIGN((unsigned long)hash + crypto_ahash_alignmask(auth), | |
145 | crypto_ahash_alignmask(auth) + 1); | |
146 | ||
147 | ahash_request_set_tfm(ahreq, auth); | |
148 | ahash_request_set_crypt(ahreq, req->dst, hash, | |
149 | req->assoclen + req->cryptlen); | |
150 | ahash_request_set_callback(ahreq, flags, | |
151 | authenc_geniv_ahash_done, req); | |
152 | ||
153 | err = crypto_ahash_digest(ahreq); | |
154 | if (err) | |
155 | return err; | |
156 | ||
157 | scatterwalk_map_and_copy(hash, req->dst, req->assoclen + req->cryptlen, | |
158 | crypto_aead_authsize(authenc), 1); | |
159 | ||
160 | return 0; | |
161 | } | |
162 | ||
163 | static void crypto_authenc_encrypt_done(struct crypto_async_request *req, | |
164 | int err) | |
165 | { | |
166 | struct aead_request *areq = req->data; | |
167 | ||
168 | if (err) | |
169 | goto out; | |
170 | ||
171 | err = crypto_authenc_genicv(areq, 0); | |
172 | ||
173 | out: | |
174 | authenc_request_complete(areq, err); | |
175 | } | |
176 | ||
177 | static int crypto_authenc_copy_assoc(struct aead_request *req) | |
178 | { | |
179 | struct crypto_aead *authenc = crypto_aead_reqtfm(req); | |
180 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); | |
181 | SYNC_SKCIPHER_REQUEST_ON_STACK(skreq, ctx->null); | |
182 | ||
183 | skcipher_request_set_sync_tfm(skreq, ctx->null); | |
184 | skcipher_request_set_callback(skreq, aead_request_flags(req), | |
185 | NULL, NULL); | |
186 | skcipher_request_set_crypt(skreq, req->src, req->dst, req->assoclen, | |
187 | NULL); | |
188 | ||
189 | return crypto_skcipher_encrypt(skreq); | |
190 | } | |
191 | ||
192 | static int crypto_authenc_encrypt(struct aead_request *req) | |
193 | { | |
194 | struct crypto_aead *authenc = crypto_aead_reqtfm(req); | |
195 | struct aead_instance *inst = aead_alg_instance(authenc); | |
196 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); | |
197 | struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); | |
198 | struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); | |
199 | struct crypto_skcipher *enc = ctx->enc; | |
200 | unsigned int cryptlen = req->cryptlen; | |
201 | struct skcipher_request *skreq = (void *)(areq_ctx->tail + | |
202 | ictx->reqoff); | |
203 | struct scatterlist *src, *dst; | |
204 | int err; | |
205 | ||
206 | src = scatterwalk_ffwd(areq_ctx->src, req->src, req->assoclen); | |
207 | dst = src; | |
208 | ||
209 | if (req->src != req->dst) { | |
210 | err = crypto_authenc_copy_assoc(req); | |
211 | if (err) | |
212 | return err; | |
213 | ||
214 | dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen); | |
215 | } | |
216 | ||
217 | skcipher_request_set_tfm(skreq, enc); | |
218 | skcipher_request_set_callback(skreq, aead_request_flags(req), | |
219 | crypto_authenc_encrypt_done, req); | |
220 | skcipher_request_set_crypt(skreq, src, dst, cryptlen, req->iv); | |
221 | ||
222 | err = crypto_skcipher_encrypt(skreq); | |
223 | if (err) | |
224 | return err; | |
225 | ||
226 | return crypto_authenc_genicv(req, aead_request_flags(req)); | |
227 | } | |
228 | ||
229 | static int crypto_authenc_decrypt_tail(struct aead_request *req, | |
230 | unsigned int flags) | |
231 | { | |
232 | struct crypto_aead *authenc = crypto_aead_reqtfm(req); | |
233 | struct aead_instance *inst = aead_alg_instance(authenc); | |
234 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); | |
235 | struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); | |
236 | struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); | |
237 | struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); | |
238 | struct skcipher_request *skreq = (void *)(areq_ctx->tail + | |
239 | ictx->reqoff); | |
240 | unsigned int authsize = crypto_aead_authsize(authenc); | |
241 | u8 *ihash = ahreq->result + authsize; | |
242 | struct scatterlist *src, *dst; | |
243 | ||
244 | scatterwalk_map_and_copy(ihash, req->src, ahreq->nbytes, authsize, 0); | |
245 | ||
246 | if (crypto_memneq(ihash, ahreq->result, authsize)) | |
247 | return -EBADMSG; | |
248 | ||
249 | src = scatterwalk_ffwd(areq_ctx->src, req->src, req->assoclen); | |
250 | dst = src; | |
251 | ||
252 | if (req->src != req->dst) | |
253 | dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen); | |
254 | ||
255 | skcipher_request_set_tfm(skreq, ctx->enc); | |
256 | skcipher_request_set_callback(skreq, aead_request_flags(req), | |
257 | req->base.complete, req->base.data); | |
258 | skcipher_request_set_crypt(skreq, src, dst, | |
259 | req->cryptlen - authsize, req->iv); | |
260 | ||
261 | return crypto_skcipher_decrypt(skreq); | |
262 | } | |
263 | ||
264 | static void authenc_verify_ahash_done(struct crypto_async_request *areq, | |
265 | int err) | |
266 | { | |
267 | struct aead_request *req = areq->data; | |
268 | ||
269 | if (err) | |
270 | goto out; | |
271 | ||
272 | err = crypto_authenc_decrypt_tail(req, 0); | |
273 | ||
274 | out: | |
275 | authenc_request_complete(req, err); | |
276 | } | |
277 | ||
278 | static int crypto_authenc_decrypt(struct aead_request *req) | |
279 | { | |
280 | struct crypto_aead *authenc = crypto_aead_reqtfm(req); | |
281 | unsigned int authsize = crypto_aead_authsize(authenc); | |
282 | struct aead_instance *inst = aead_alg_instance(authenc); | |
283 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); | |
284 | struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); | |
285 | struct crypto_ahash *auth = ctx->auth; | |
286 | struct authenc_request_ctx *areq_ctx = aead_request_ctx(req); | |
287 | struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff); | |
288 | u8 *hash = areq_ctx->tail; | |
289 | int err; | |
290 | ||
291 | hash = (u8 *)ALIGN((unsigned long)hash + crypto_ahash_alignmask(auth), | |
292 | crypto_ahash_alignmask(auth) + 1); | |
293 | ||
294 | ahash_request_set_tfm(ahreq, auth); | |
295 | ahash_request_set_crypt(ahreq, req->src, hash, | |
296 | req->assoclen + req->cryptlen - authsize); | |
297 | ahash_request_set_callback(ahreq, aead_request_flags(req), | |
298 | authenc_verify_ahash_done, req); | |
299 | ||
300 | err = crypto_ahash_digest(ahreq); | |
301 | if (err) | |
302 | return err; | |
303 | ||
304 | return crypto_authenc_decrypt_tail(req, aead_request_flags(req)); | |
305 | } | |
306 | ||
307 | static int crypto_authenc_init_tfm(struct crypto_aead *tfm) | |
308 | { | |
309 | struct aead_instance *inst = aead_alg_instance(tfm); | |
310 | struct authenc_instance_ctx *ictx = aead_instance_ctx(inst); | |
311 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm); | |
312 | struct crypto_ahash *auth; | |
313 | struct crypto_skcipher *enc; | |
314 | struct crypto_sync_skcipher *null; | |
315 | int err; | |
316 | ||
317 | auth = crypto_spawn_ahash(&ictx->auth); | |
318 | if (IS_ERR(auth)) | |
319 | return PTR_ERR(auth); | |
320 | ||
321 | enc = crypto_spawn_skcipher(&ictx->enc); | |
322 | err = PTR_ERR(enc); | |
323 | if (IS_ERR(enc)) | |
324 | goto err_free_ahash; | |
325 | ||
326 | null = crypto_get_default_null_skcipher(); | |
327 | err = PTR_ERR(null); | |
328 | if (IS_ERR(null)) | |
329 | goto err_free_skcipher; | |
330 | ||
331 | ctx->auth = auth; | |
332 | ctx->enc = enc; | |
333 | ctx->null = null; | |
334 | ||
335 | crypto_aead_set_reqsize( | |
336 | tfm, | |
337 | sizeof(struct authenc_request_ctx) + | |
338 | ictx->reqoff + | |
339 | max_t(unsigned int, | |
340 | crypto_ahash_reqsize(auth) + | |
341 | sizeof(struct ahash_request), | |
342 | sizeof(struct skcipher_request) + | |
343 | crypto_skcipher_reqsize(enc))); | |
344 | ||
345 | return 0; | |
346 | ||
347 | err_free_skcipher: | |
348 | crypto_free_skcipher(enc); | |
349 | err_free_ahash: | |
350 | crypto_free_ahash(auth); | |
351 | return err; | |
352 | } | |
353 | ||
354 | static void crypto_authenc_exit_tfm(struct crypto_aead *tfm) | |
355 | { | |
356 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm); | |
357 | ||
358 | crypto_free_ahash(ctx->auth); | |
359 | crypto_free_skcipher(ctx->enc); | |
360 | crypto_put_default_null_skcipher(); | |
361 | } | |
362 | ||
363 | static void crypto_authenc_free(struct aead_instance *inst) | |
364 | { | |
365 | struct authenc_instance_ctx *ctx = aead_instance_ctx(inst); | |
366 | ||
367 | crypto_drop_skcipher(&ctx->enc); | |
368 | crypto_drop_ahash(&ctx->auth); | |
369 | kfree(inst); | |
370 | } | |
371 | ||
372 | static int crypto_authenc_create(struct crypto_template *tmpl, | |
373 | struct rtattr **tb) | |
374 | { | |
375 | u32 mask; | |
376 | struct aead_instance *inst; | |
377 | struct authenc_instance_ctx *ctx; | |
378 | struct hash_alg_common *auth; | |
379 | struct crypto_alg *auth_base; | |
380 | struct skcipher_alg *enc; | |
381 | int err; | |
382 | ||
383 | err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD, &mask); | |
384 | if (err) | |
385 | return err; | |
386 | ||
387 | inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL); | |
388 | if (!inst) | |
389 | return -ENOMEM; | |
390 | ctx = aead_instance_ctx(inst); | |
391 | ||
392 | err = crypto_grab_ahash(&ctx->auth, aead_crypto_instance(inst), | |
393 | crypto_attr_alg_name(tb[1]), 0, mask); | |
394 | if (err) | |
395 | goto err_free_inst; | |
396 | auth = crypto_spawn_ahash_alg(&ctx->auth); | |
397 | auth_base = &auth->base; | |
398 | ||
399 | err = crypto_grab_skcipher(&ctx->enc, aead_crypto_instance(inst), | |
400 | crypto_attr_alg_name(tb[2]), 0, mask); | |
401 | if (err) | |
402 | goto err_free_inst; | |
403 | enc = crypto_spawn_skcipher_alg(&ctx->enc); | |
404 | ||
405 | ctx->reqoff = ALIGN(2 * auth->digestsize + auth_base->cra_alignmask, | |
406 | auth_base->cra_alignmask + 1); | |
407 | ||
408 | err = -ENAMETOOLONG; | |
409 | if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME, | |
410 | "authenc(%s,%s)", auth_base->cra_name, | |
411 | enc->base.cra_name) >= | |
412 | CRYPTO_MAX_ALG_NAME) | |
413 | goto err_free_inst; | |
414 | ||
415 | if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME, | |
416 | "authenc(%s,%s)", auth_base->cra_driver_name, | |
417 | enc->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME) | |
418 | goto err_free_inst; | |
419 | ||
420 | inst->alg.base.cra_priority = enc->base.cra_priority * 10 + | |
421 | auth_base->cra_priority; | |
422 | inst->alg.base.cra_blocksize = enc->base.cra_blocksize; | |
423 | inst->alg.base.cra_alignmask = auth_base->cra_alignmask | | |
424 | enc->base.cra_alignmask; | |
425 | inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_ctx); | |
426 | ||
427 | inst->alg.ivsize = crypto_skcipher_alg_ivsize(enc); | |
428 | inst->alg.chunksize = crypto_skcipher_alg_chunksize(enc); | |
429 | inst->alg.maxauthsize = auth->digestsize; | |
430 | ||
431 | inst->alg.init = crypto_authenc_init_tfm; | |
432 | inst->alg.exit = crypto_authenc_exit_tfm; | |
433 | ||
434 | inst->alg.setkey = crypto_authenc_setkey; | |
435 | inst->alg.encrypt = crypto_authenc_encrypt; | |
436 | inst->alg.decrypt = crypto_authenc_decrypt; | |
437 | ||
438 | inst->free = crypto_authenc_free; | |
439 | ||
440 | err = aead_register_instance(tmpl, inst); | |
441 | if (err) { | |
442 | err_free_inst: | |
443 | crypto_authenc_free(inst); | |
444 | } | |
445 | return err; | |
446 | } | |
447 | ||
448 | static struct crypto_template crypto_authenc_tmpl = { | |
449 | .name = "authenc", | |
450 | .create = crypto_authenc_create, | |
451 | .module = THIS_MODULE, | |
452 | }; | |
453 | ||
454 | static int __init crypto_authenc_module_init(void) | |
455 | { | |
456 | return crypto_register_template(&crypto_authenc_tmpl); | |
457 | } | |
458 | ||
459 | static void __exit crypto_authenc_module_exit(void) | |
460 | { | |
461 | crypto_unregister_template(&crypto_authenc_tmpl); | |
462 | } | |
463 | ||
464 | subsys_initcall(crypto_authenc_module_init); | |
465 | module_exit(crypto_authenc_module_exit); | |
466 | ||
467 | MODULE_LICENSE("GPL"); | |
468 | MODULE_DESCRIPTION("Simple AEAD wrapper for IPsec"); | |
469 | MODULE_ALIAS_CRYPTO("authenc"); |