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
authenc_esn_request_complete(struct aead_request * req,int err)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
crypto_authenc_esn_setauthsize(struct crypto_aead * authenc_esn,unsigned int authsize)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
crypto_authenc_esn_setkey(struct crypto_aead * authenc_esn,const u8 * key,unsigned int keylen)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 badkey;
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 crypto_aead_set_flags(authenc_esn, crypto_ahash_get_flags(auth) &
75 CRYPTO_TFM_RES_MASK);
76
77 if (err)
78 goto out;
79
80 crypto_skcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK);
81 crypto_skcipher_set_flags(enc, crypto_aead_get_flags(authenc_esn) &
82 CRYPTO_TFM_REQ_MASK);
83 err = crypto_skcipher_setkey(enc, keys.enckey, keys.enckeylen);
84 crypto_aead_set_flags(authenc_esn, crypto_skcipher_get_flags(enc) &
85 CRYPTO_TFM_RES_MASK);
86
87 out:
88 memzero_explicit(&keys, sizeof(keys));
89 return err;
90
91 badkey:
92 crypto_aead_set_flags(authenc_esn, CRYPTO_TFM_RES_BAD_KEY_LEN);
93 goto out;
94 }
95
crypto_authenc_esn_genicv_tail(struct aead_request * req,unsigned int flags)96 static int crypto_authenc_esn_genicv_tail(struct aead_request *req,
97 unsigned int flags)
98 {
99 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
100 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
101 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
102 struct crypto_ahash *auth = ctx->auth;
103 u8 *hash = PTR_ALIGN((u8 *)areq_ctx->tail,
104 crypto_ahash_alignmask(auth) + 1);
105 unsigned int authsize = crypto_aead_authsize(authenc_esn);
106 unsigned int assoclen = req->assoclen;
107 unsigned int cryptlen = req->cryptlen;
108 struct scatterlist *dst = req->dst;
109 u32 tmp[2];
110
111 /* Move high-order bits of sequence number back. */
112 scatterwalk_map_and_copy(tmp, dst, 4, 4, 0);
113 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 0);
114 scatterwalk_map_and_copy(tmp, dst, 0, 8, 1);
115
116 scatterwalk_map_and_copy(hash, dst, assoclen + cryptlen, authsize, 1);
117 return 0;
118 }
119
authenc_esn_geniv_ahash_done(struct crypto_async_request * areq,int err)120 static void authenc_esn_geniv_ahash_done(struct crypto_async_request *areq,
121 int err)
122 {
123 struct aead_request *req = areq->data;
124
125 err = err ?: crypto_authenc_esn_genicv_tail(req, 0);
126 aead_request_complete(req, err);
127 }
128
crypto_authenc_esn_genicv(struct aead_request * req,unsigned int flags)129 static int crypto_authenc_esn_genicv(struct aead_request *req,
130 unsigned int flags)
131 {
132 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
133 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
134 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
135 struct crypto_ahash *auth = ctx->auth;
136 u8 *hash = PTR_ALIGN((u8 *)areq_ctx->tail,
137 crypto_ahash_alignmask(auth) + 1);
138 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff);
139 unsigned int authsize = crypto_aead_authsize(authenc_esn);
140 unsigned int assoclen = req->assoclen;
141 unsigned int cryptlen = req->cryptlen;
142 struct scatterlist *dst = req->dst;
143 u32 tmp[2];
144
145 if (!authsize)
146 return 0;
147
148 /* Move high-order bits of sequence number to the end. */
149 scatterwalk_map_and_copy(tmp, dst, 0, 8, 0);
150 scatterwalk_map_and_copy(tmp, dst, 4, 4, 1);
151 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 1);
152
153 sg_init_table(areq_ctx->dst, 2);
154 dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4);
155
156 ahash_request_set_tfm(ahreq, auth);
157 ahash_request_set_crypt(ahreq, dst, hash, assoclen + cryptlen);
158 ahash_request_set_callback(ahreq, flags,
159 authenc_esn_geniv_ahash_done, req);
160
161 return crypto_ahash_digest(ahreq) ?:
162 crypto_authenc_esn_genicv_tail(req, aead_request_flags(req));
163 }
164
165
crypto_authenc_esn_encrypt_done(struct crypto_async_request * req,int err)166 static void crypto_authenc_esn_encrypt_done(struct crypto_async_request *req,
167 int err)
168 {
169 struct aead_request *areq = req->data;
170
171 if (!err)
172 err = crypto_authenc_esn_genicv(areq, 0);
173
174 authenc_esn_request_complete(areq, err);
175 }
176
crypto_authenc_esn_copy(struct aead_request * req,unsigned int len)177 static int crypto_authenc_esn_copy(struct aead_request *req, unsigned int len)
178 {
179 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
180 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
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, len, NULL);
187
188 return crypto_skcipher_encrypt(skreq);
189 }
190
crypto_authenc_esn_encrypt(struct aead_request * req)191 static int crypto_authenc_esn_encrypt(struct aead_request *req)
192 {
193 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
194 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
195 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
196 struct skcipher_request *skreq = (void *)(areq_ctx->tail +
197 ctx->reqoff);
198 struct crypto_skcipher *enc = ctx->enc;
199 unsigned int assoclen = req->assoclen;
200 unsigned int cryptlen = req->cryptlen;
201 struct scatterlist *src, *dst;
202 int err;
203
204 sg_init_table(areq_ctx->src, 2);
205 src = scatterwalk_ffwd(areq_ctx->src, req->src, assoclen);
206 dst = src;
207
208 if (req->src != req->dst) {
209 err = crypto_authenc_esn_copy(req, assoclen);
210 if (err)
211 return err;
212
213 sg_init_table(areq_ctx->dst, 2);
214 dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, assoclen);
215 }
216
217 skcipher_request_set_tfm(skreq, enc);
218 skcipher_request_set_callback(skreq, aead_request_flags(req),
219 crypto_authenc_esn_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_esn_genicv(req, aead_request_flags(req));
227 }
228
crypto_authenc_esn_decrypt_tail(struct aead_request * req,unsigned int flags)229 static int crypto_authenc_esn_decrypt_tail(struct aead_request *req,
230 unsigned int flags)
231 {
232 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
233 unsigned int authsize = crypto_aead_authsize(authenc_esn);
234 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
235 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
236 struct skcipher_request *skreq = (void *)(areq_ctx->tail +
237 ctx->reqoff);
238 struct crypto_ahash *auth = ctx->auth;
239 u8 *ohash = PTR_ALIGN((u8 *)areq_ctx->tail,
240 crypto_ahash_alignmask(auth) + 1);
241 unsigned int cryptlen = req->cryptlen - authsize;
242 unsigned int assoclen = req->assoclen;
243 struct scatterlist *dst = req->dst;
244 u8 *ihash = ohash + crypto_ahash_digestsize(auth);
245 u32 tmp[2];
246
247 if (!authsize)
248 goto decrypt;
249
250 /* Move high-order bits of sequence number back. */
251 scatterwalk_map_and_copy(tmp, dst, 4, 4, 0);
252 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 0);
253 scatterwalk_map_and_copy(tmp, dst, 0, 8, 1);
254
255 if (crypto_memneq(ihash, ohash, authsize))
256 return -EBADMSG;
257
258 decrypt:
259
260 sg_init_table(areq_ctx->dst, 2);
261 dst = scatterwalk_ffwd(areq_ctx->dst, dst, assoclen);
262
263 skcipher_request_set_tfm(skreq, ctx->enc);
264 skcipher_request_set_callback(skreq, flags,
265 req->base.complete, req->base.data);
266 skcipher_request_set_crypt(skreq, dst, dst, cryptlen, req->iv);
267
268 return crypto_skcipher_decrypt(skreq);
269 }
270
authenc_esn_verify_ahash_done(struct crypto_async_request * areq,int err)271 static void authenc_esn_verify_ahash_done(struct crypto_async_request *areq,
272 int err)
273 {
274 struct aead_request *req = areq->data;
275
276 err = err ?: crypto_authenc_esn_decrypt_tail(req, 0);
277 authenc_esn_request_complete(req, err);
278 }
279
crypto_authenc_esn_decrypt(struct aead_request * req)280 static int crypto_authenc_esn_decrypt(struct aead_request *req)
281 {
282 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
283 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
284 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
285 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff);
286 unsigned int authsize = crypto_aead_authsize(authenc_esn);
287 struct crypto_ahash *auth = ctx->auth;
288 u8 *ohash = PTR_ALIGN((u8 *)areq_ctx->tail,
289 crypto_ahash_alignmask(auth) + 1);
290 unsigned int assoclen = req->assoclen;
291 unsigned int cryptlen = req->cryptlen;
292 u8 *ihash = ohash + crypto_ahash_digestsize(auth);
293 struct scatterlist *dst = req->dst;
294 u32 tmp[2];
295 int err;
296
297 cryptlen -= authsize;
298
299 if (req->src != dst) {
300 err = crypto_authenc_esn_copy(req, assoclen + cryptlen);
301 if (err)
302 return err;
303 }
304
305 scatterwalk_map_and_copy(ihash, req->src, assoclen + cryptlen,
306 authsize, 0);
307
308 if (!authsize)
309 goto tail;
310
311 /* Move high-order bits of sequence number to the end. */
312 scatterwalk_map_and_copy(tmp, dst, 0, 8, 0);
313 scatterwalk_map_and_copy(tmp, dst, 4, 4, 1);
314 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 1);
315
316 sg_init_table(areq_ctx->dst, 2);
317 dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4);
318
319 ahash_request_set_tfm(ahreq, auth);
320 ahash_request_set_crypt(ahreq, dst, ohash, assoclen + cryptlen);
321 ahash_request_set_callback(ahreq, aead_request_flags(req),
322 authenc_esn_verify_ahash_done, req);
323
324 err = crypto_ahash_digest(ahreq);
325 if (err)
326 return err;
327
328 tail:
329 return crypto_authenc_esn_decrypt_tail(req, aead_request_flags(req));
330 }
331
crypto_authenc_esn_init_tfm(struct crypto_aead * tfm)332 static int crypto_authenc_esn_init_tfm(struct crypto_aead *tfm)
333 {
334 struct aead_instance *inst = aead_alg_instance(tfm);
335 struct authenc_esn_instance_ctx *ictx = aead_instance_ctx(inst);
336 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm);
337 struct crypto_ahash *auth;
338 struct crypto_skcipher *enc;
339 struct crypto_sync_skcipher *null;
340 int err;
341
342 auth = crypto_spawn_ahash(&ictx->auth);
343 if (IS_ERR(auth))
344 return PTR_ERR(auth);
345
346 enc = crypto_spawn_skcipher(&ictx->enc);
347 err = PTR_ERR(enc);
348 if (IS_ERR(enc))
349 goto err_free_ahash;
350
351 null = crypto_get_default_null_skcipher();
352 err = PTR_ERR(null);
353 if (IS_ERR(null))
354 goto err_free_skcipher;
355
356 ctx->auth = auth;
357 ctx->enc = enc;
358 ctx->null = null;
359
360 ctx->reqoff = ALIGN(2 * crypto_ahash_digestsize(auth),
361 crypto_ahash_alignmask(auth) + 1);
362
363 crypto_aead_set_reqsize(
364 tfm,
365 sizeof(struct authenc_esn_request_ctx) +
366 ctx->reqoff +
367 max_t(unsigned int,
368 crypto_ahash_reqsize(auth) +
369 sizeof(struct ahash_request),
370 sizeof(struct skcipher_request) +
371 crypto_skcipher_reqsize(enc)));
372
373 return 0;
374
375 err_free_skcipher:
376 crypto_free_skcipher(enc);
377 err_free_ahash:
378 crypto_free_ahash(auth);
379 return err;
380 }
381
crypto_authenc_esn_exit_tfm(struct crypto_aead * tfm)382 static void crypto_authenc_esn_exit_tfm(struct crypto_aead *tfm)
383 {
384 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm);
385
386 crypto_free_ahash(ctx->auth);
387 crypto_free_skcipher(ctx->enc);
388 crypto_put_default_null_skcipher();
389 }
390
crypto_authenc_esn_free(struct aead_instance * inst)391 static void crypto_authenc_esn_free(struct aead_instance *inst)
392 {
393 struct authenc_esn_instance_ctx *ctx = aead_instance_ctx(inst);
394
395 crypto_drop_skcipher(&ctx->enc);
396 crypto_drop_ahash(&ctx->auth);
397 kfree(inst);
398 }
399
crypto_authenc_esn_create(struct crypto_template * tmpl,struct rtattr ** tb)400 static int crypto_authenc_esn_create(struct crypto_template *tmpl,
401 struct rtattr **tb)
402 {
403 struct crypto_attr_type *algt;
404 struct aead_instance *inst;
405 struct hash_alg_common *auth;
406 struct crypto_alg *auth_base;
407 struct skcipher_alg *enc;
408 struct authenc_esn_instance_ctx *ctx;
409 const char *enc_name;
410 int err;
411
412 algt = crypto_get_attr_type(tb);
413 if (IS_ERR(algt))
414 return PTR_ERR(algt);
415
416 if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
417 return -EINVAL;
418
419 auth = ahash_attr_alg(tb[1], CRYPTO_ALG_TYPE_HASH,
420 CRYPTO_ALG_TYPE_AHASH_MASK |
421 crypto_requires_sync(algt->type, algt->mask));
422 if (IS_ERR(auth))
423 return PTR_ERR(auth);
424
425 auth_base = &auth->base;
426
427 enc_name = crypto_attr_alg_name(tb[2]);
428 err = PTR_ERR(enc_name);
429 if (IS_ERR(enc_name))
430 goto out_put_auth;
431
432 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
433 err = -ENOMEM;
434 if (!inst)
435 goto out_put_auth;
436
437 ctx = aead_instance_ctx(inst);
438
439 err = crypto_init_ahash_spawn(&ctx->auth, auth,
440 aead_crypto_instance(inst));
441 if (err)
442 goto err_free_inst;
443
444 crypto_set_skcipher_spawn(&ctx->enc, aead_crypto_instance(inst));
445 err = crypto_grab_skcipher(&ctx->enc, enc_name, 0,
446 crypto_requires_sync(algt->type,
447 algt->mask));
448 if (err)
449 goto err_drop_auth;
450
451 enc = crypto_spawn_skcipher_alg(&ctx->enc);
452
453 err = -ENAMETOOLONG;
454 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
455 "authencesn(%s,%s)", auth_base->cra_name,
456 enc->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
457 goto err_drop_enc;
458
459 if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
460 "authencesn(%s,%s)", auth_base->cra_driver_name,
461 enc->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
462 goto err_drop_enc;
463
464 inst->alg.base.cra_flags = (auth_base->cra_flags |
465 enc->base.cra_flags) & CRYPTO_ALG_ASYNC;
466 inst->alg.base.cra_priority = enc->base.cra_priority * 10 +
467 auth_base->cra_priority;
468 inst->alg.base.cra_blocksize = enc->base.cra_blocksize;
469 inst->alg.base.cra_alignmask = auth_base->cra_alignmask |
470 enc->base.cra_alignmask;
471 inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_esn_ctx);
472
473 inst->alg.ivsize = crypto_skcipher_alg_ivsize(enc);
474 inst->alg.chunksize = crypto_skcipher_alg_chunksize(enc);
475 inst->alg.maxauthsize = auth->digestsize;
476
477 inst->alg.init = crypto_authenc_esn_init_tfm;
478 inst->alg.exit = crypto_authenc_esn_exit_tfm;
479
480 inst->alg.setkey = crypto_authenc_esn_setkey;
481 inst->alg.setauthsize = crypto_authenc_esn_setauthsize;
482 inst->alg.encrypt = crypto_authenc_esn_encrypt;
483 inst->alg.decrypt = crypto_authenc_esn_decrypt;
484
485 inst->free = crypto_authenc_esn_free,
486
487 err = aead_register_instance(tmpl, inst);
488 if (err)
489 goto err_drop_enc;
490
491 out:
492 crypto_mod_put(auth_base);
493 return err;
494
495 err_drop_enc:
496 crypto_drop_skcipher(&ctx->enc);
497 err_drop_auth:
498 crypto_drop_ahash(&ctx->auth);
499 err_free_inst:
500 kfree(inst);
501 out_put_auth:
502 goto out;
503 }
504
505 static struct crypto_template crypto_authenc_esn_tmpl = {
506 .name = "authencesn",
507 .create = crypto_authenc_esn_create,
508 .module = THIS_MODULE,
509 };
510
crypto_authenc_esn_module_init(void)511 static int __init crypto_authenc_esn_module_init(void)
512 {
513 return crypto_register_template(&crypto_authenc_esn_tmpl);
514 }
515
crypto_authenc_esn_module_exit(void)516 static void __exit crypto_authenc_esn_module_exit(void)
517 {
518 crypto_unregister_template(&crypto_authenc_esn_tmpl);
519 }
520
521 subsys_initcall(crypto_authenc_esn_module_init);
522 module_exit(crypto_authenc_esn_module_exit);
523
524 MODULE_LICENSE("GPL");
525 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
526 MODULE_DESCRIPTION("AEAD wrapper for IPsec with extended sequence numbers");
527 MODULE_ALIAS_CRYPTO("authencesn");
528