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