1/*
2 * authencesn.c - AEAD wrapper for IPsec with extended sequence numbers,
3 * derived from authenc.c
4 *
5 * Copyright (C) 2010 secunet Security Networks AG
6 * Copyright (C) 2010 Steffen Klassert <steffen.klassert@secunet.com>
7 * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
8 *
9 * This program is free software; you can redistribute it and/or modify it
10 * under the terms of the GNU General Public License as published by the Free
11 * Software Foundation; either version 2 of the License, or (at your option)
12 * any later version.
13 *
14 */
15
16#include <crypto/internal/aead.h>
17#include <crypto/internal/hash.h>
18#include <crypto/internal/skcipher.h>
19#include <crypto/authenc.h>
20#include <crypto/null.h>
21#include <crypto/scatterwalk.h>
22#include <linux/err.h>
23#include <linux/init.h>
24#include <linux/kernel.h>
25#include <linux/module.h>
26#include <linux/rtnetlink.h>
27#include <linux/slab.h>
28#include <linux/spinlock.h>
29
30struct authenc_esn_instance_ctx {
31 struct crypto_ahash_spawn auth;
32 struct crypto_skcipher_spawn enc;
33};
34
35struct crypto_authenc_esn_ctx {
36 unsigned int reqoff;
37 struct crypto_ahash *auth;
38 struct crypto_skcipher *enc;
39 struct crypto_sync_skcipher *null;
40};
41
42struct authenc_esn_request_ctx {
43 struct scatterlist src[2];
44 struct scatterlist dst[2];
45 char tail[];
46};
47
48static void authenc_esn_request_complete(struct aead_request *req, int err)
49{
50 if (err != -EINPROGRESS)
51 aead_request_complete(req, err);
52}
53
54static int crypto_authenc_esn_setauthsize(struct crypto_aead *authenc_esn,
55 unsigned int authsize)
56{
57 if (authsize > 0 && authsize < 4)
58 return -EINVAL;
59
60 return 0;
61}
62
63static int crypto_authenc_esn_setkey(struct crypto_aead *authenc_esn, const u8 *key,
64 unsigned int keylen)
65{
66 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
67 struct crypto_ahash *auth = ctx->auth;
68 struct crypto_skcipher *enc = ctx->enc;
69 struct crypto_authenc_keys keys;
70 int err = -EINVAL;
71
72 if (crypto_authenc_extractkeys(&keys, key, keylen) != 0)
73 goto badkey;
74
75 crypto_ahash_clear_flags(auth, CRYPTO_TFM_REQ_MASK);
76 crypto_ahash_set_flags(auth, crypto_aead_get_flags(authenc_esn) &
77 CRYPTO_TFM_REQ_MASK);
78 err = crypto_ahash_setkey(auth, keys.authkey, keys.authkeylen);
79 crypto_aead_set_flags(authenc_esn, crypto_ahash_get_flags(auth) &
80 CRYPTO_TFM_RES_MASK);
81
82 if (err)
83 goto out;
84
85 crypto_skcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK);
86 crypto_skcipher_set_flags(enc, crypto_aead_get_flags(authenc_esn) &
87 CRYPTO_TFM_REQ_MASK);
88 err = crypto_skcipher_setkey(enc, keys.enckey, keys.enckeylen);
89 crypto_aead_set_flags(authenc_esn, crypto_skcipher_get_flags(enc) &
90 CRYPTO_TFM_RES_MASK);
91
92out:
93 memzero_explicit(&keys, sizeof(keys));
94 return err;
95
96badkey:
97 crypto_aead_set_flags(authenc_esn, CRYPTO_TFM_RES_BAD_KEY_LEN);
98 goto out;
99}
100
101static int crypto_authenc_esn_genicv_tail(struct aead_request *req,
102 unsigned int flags)
103{
104 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
105 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
106 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
107 struct crypto_ahash *auth = ctx->auth;
108 u8 *hash = PTR_ALIGN((u8 *)areq_ctx->tail,
109 crypto_ahash_alignmask(auth) + 1);
110 unsigned int authsize = crypto_aead_authsize(authenc_esn);
111 unsigned int assoclen = req->assoclen;
112 unsigned int cryptlen = req->cryptlen;
113 struct scatterlist *dst = req->dst;
114 u32 tmp[2];
115
116 /* Move high-order bits of sequence number back. */
117 scatterwalk_map_and_copy(tmp, dst, 4, 4, 0);
118 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 0);
119 scatterwalk_map_and_copy(tmp, dst, 0, 8, 1);
120
121 scatterwalk_map_and_copy(hash, dst, assoclen + cryptlen, authsize, 1);
122 return 0;
123}
124
125static void authenc_esn_geniv_ahash_done(struct crypto_async_request *areq,
126 int err)
127{
128 struct aead_request *req = areq->data;
129
130 err = err ?: crypto_authenc_esn_genicv_tail(req, 0);
131 aead_request_complete(req, err);
132}
133
134static int crypto_authenc_esn_genicv(struct aead_request *req,
135 unsigned int flags)
136{
137 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
138 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
139 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
140 struct crypto_ahash *auth = ctx->auth;
141 u8 *hash = PTR_ALIGN((u8 *)areq_ctx->tail,
142 crypto_ahash_alignmask(auth) + 1);
143 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff);
144 unsigned int authsize = crypto_aead_authsize(authenc_esn);
145 unsigned int assoclen = req->assoclen;
146 unsigned int cryptlen = req->cryptlen;
147 struct scatterlist *dst = req->dst;
148 u32 tmp[2];
149
150 if (!authsize)
151 return 0;
152
153 /* Move high-order bits of sequence number to the end. */
154 scatterwalk_map_and_copy(tmp, dst, 0, 8, 0);
155 scatterwalk_map_and_copy(tmp, dst, 4, 4, 1);
156 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 1);
157
158 sg_init_table(areq_ctx->dst, 2);
159 dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4);
160
161 ahash_request_set_tfm(ahreq, auth);
162 ahash_request_set_crypt(ahreq, dst, hash, assoclen + cryptlen);
163 ahash_request_set_callback(ahreq, flags,
164 authenc_esn_geniv_ahash_done, req);
165
166 return crypto_ahash_digest(ahreq) ?:
167 crypto_authenc_esn_genicv_tail(req, aead_request_flags(req));
168}
169
170
171static void crypto_authenc_esn_encrypt_done(struct crypto_async_request *req,
172 int err)
173{
174 struct aead_request *areq = req->data;
175
176 if (!err)
177 err = crypto_authenc_esn_genicv(areq, 0);
178
179 authenc_esn_request_complete(areq, err);
180}
181
182static int crypto_authenc_esn_copy(struct aead_request *req, unsigned int len)
183{
184 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
185 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
186 SYNC_SKCIPHER_REQUEST_ON_STACK(skreq, ctx->null);
187
188 skcipher_request_set_sync_tfm(skreq, ctx->null);
189 skcipher_request_set_callback(skreq, aead_request_flags(req),
190 NULL, NULL);
191 skcipher_request_set_crypt(skreq, req->src, req->dst, len, NULL);
192
193 return crypto_skcipher_encrypt(skreq);
194}
195
196static int crypto_authenc_esn_encrypt(struct aead_request *req)
197{
198 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
199 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
200 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
201 struct skcipher_request *skreq = (void *)(areq_ctx->tail +
202 ctx->reqoff);
203 struct crypto_skcipher *enc = ctx->enc;
204 unsigned int assoclen = req->assoclen;
205 unsigned int cryptlen = req->cryptlen;
206 struct scatterlist *src, *dst;
207 int err;
208
209 sg_init_table(areq_ctx->src, 2);
210 src = scatterwalk_ffwd(areq_ctx->src, req->src, assoclen);
211 dst = src;
212
213 if (req->src != req->dst) {
214 err = crypto_authenc_esn_copy(req, assoclen);
215 if (err)
216 return err;
217
218 sg_init_table(areq_ctx->dst, 2);
219 dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, assoclen);
220 }
221
222 skcipher_request_set_tfm(skreq, enc);
223 skcipher_request_set_callback(skreq, aead_request_flags(req),
224 crypto_authenc_esn_encrypt_done, req);
225 skcipher_request_set_crypt(skreq, src, dst, cryptlen, req->iv);
226
227 err = crypto_skcipher_encrypt(skreq);
228 if (err)
229 return err;
230
231 return crypto_authenc_esn_genicv(req, aead_request_flags(req));
232}
233
234static int crypto_authenc_esn_decrypt_tail(struct aead_request *req,
235 unsigned int flags)
236{
237 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
238 unsigned int authsize = crypto_aead_authsize(authenc_esn);
239 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
240 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
241 struct skcipher_request *skreq = (void *)(areq_ctx->tail +
242 ctx->reqoff);
243 struct crypto_ahash *auth = ctx->auth;
244 u8 *ohash = PTR_ALIGN((u8 *)areq_ctx->tail,
245 crypto_ahash_alignmask(auth) + 1);
246 unsigned int cryptlen = req->cryptlen - authsize;
247 unsigned int assoclen = req->assoclen;
248 struct scatterlist *dst = req->dst;
249 u8 *ihash = ohash + crypto_ahash_digestsize(auth);
250 u32 tmp[2];
251
252 if (!authsize)
253 goto decrypt;
254
255 /* Move high-order bits of sequence number back. */
256 scatterwalk_map_and_copy(tmp, dst, 4, 4, 0);
257 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 0);
258 scatterwalk_map_and_copy(tmp, dst, 0, 8, 1);
259
260 if (crypto_memneq(ihash, ohash, authsize))
261 return -EBADMSG;
262
263decrypt:
264
265 sg_init_table(areq_ctx->dst, 2);
266 dst = scatterwalk_ffwd(areq_ctx->dst, dst, assoclen);
267
268 skcipher_request_set_tfm(skreq, ctx->enc);
269 skcipher_request_set_callback(skreq, flags,
270 req->base.complete, req->base.data);
271 skcipher_request_set_crypt(skreq, dst, dst, cryptlen, req->iv);
272
273 return crypto_skcipher_decrypt(skreq);
274}
275
276static void authenc_esn_verify_ahash_done(struct crypto_async_request *areq,
277 int err)
278{
279 struct aead_request *req = areq->data;
280
281 err = err ?: crypto_authenc_esn_decrypt_tail(req, 0);
282 authenc_esn_request_complete(req, err);
283}
284
285static int crypto_authenc_esn_decrypt(struct aead_request *req)
286{
287 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
288 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
289 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
290 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff);
291 unsigned int authsize = crypto_aead_authsize(authenc_esn);
292 struct crypto_ahash *auth = ctx->auth;
293 u8 *ohash = PTR_ALIGN((u8 *)areq_ctx->tail,
294 crypto_ahash_alignmask(auth) + 1);
295 unsigned int assoclen = req->assoclen;
296 unsigned int cryptlen = req->cryptlen;
297 u8 *ihash = ohash + crypto_ahash_digestsize(auth);
298 struct scatterlist *dst = req->dst;
299 u32 tmp[2];
300 int err;
301
302 cryptlen -= authsize;
303
304 if (req->src != dst) {
305 err = crypto_authenc_esn_copy(req, assoclen + cryptlen);
306 if (err)
307 return err;
308 }
309
310 scatterwalk_map_and_copy(ihash, req->src, assoclen + cryptlen,
311 authsize, 0);
312
313 if (!authsize)
314 goto tail;
315
316 /* Move high-order bits of sequence number to the end. */
317 scatterwalk_map_and_copy(tmp, dst, 0, 8, 0);
318 scatterwalk_map_and_copy(tmp, dst, 4, 4, 1);
319 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 1);
320
321 sg_init_table(areq_ctx->dst, 2);
322 dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4);
323
324 ahash_request_set_tfm(ahreq, auth);
325 ahash_request_set_crypt(ahreq, dst, ohash, assoclen + cryptlen);
326 ahash_request_set_callback(ahreq, aead_request_flags(req),
327 authenc_esn_verify_ahash_done, req);
328
329 err = crypto_ahash_digest(ahreq);
330 if (err)
331 return err;
332
333tail:
334 return crypto_authenc_esn_decrypt_tail(req, aead_request_flags(req));
335}
336
337static int crypto_authenc_esn_init_tfm(struct crypto_aead *tfm)
338{
339 struct aead_instance *inst = aead_alg_instance(tfm);
340 struct authenc_esn_instance_ctx *ictx = aead_instance_ctx(inst);
341 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm);
342 struct crypto_ahash *auth;
343 struct crypto_skcipher *enc;
344 struct crypto_sync_skcipher *null;
345 int err;
346
347 auth = crypto_spawn_ahash(&ictx->auth);
348 if (IS_ERR(auth))
349 return PTR_ERR(auth);
350
351 enc = crypto_spawn_skcipher(&ictx->enc);
352 err = PTR_ERR(enc);
353 if (IS_ERR(enc))
354 goto err_free_ahash;
355
356 null = crypto_get_default_null_skcipher();
357 err = PTR_ERR(null);
358 if (IS_ERR(null))
359 goto err_free_skcipher;
360
361 ctx->auth = auth;
362 ctx->enc = enc;
363 ctx->null = null;
364
365 ctx->reqoff = ALIGN(2 * crypto_ahash_digestsize(auth),
366 crypto_ahash_alignmask(auth) + 1);
367
368 crypto_aead_set_reqsize(
369 tfm,
370 sizeof(struct authenc_esn_request_ctx) +
371 ctx->reqoff +
372 max_t(unsigned int,
373 crypto_ahash_reqsize(auth) +
374 sizeof(struct ahash_request),
375 sizeof(struct skcipher_request) +
376 crypto_skcipher_reqsize(enc)));
377
378 return 0;
379
380err_free_skcipher:
381 crypto_free_skcipher(enc);
382err_free_ahash:
383 crypto_free_ahash(auth);
384 return err;
385}
386
387static void crypto_authenc_esn_exit_tfm(struct crypto_aead *tfm)
388{
389 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm);
390
391 crypto_free_ahash(ctx->auth);
392 crypto_free_skcipher(ctx->enc);
393 crypto_put_default_null_skcipher();
394}
395
396static void crypto_authenc_esn_free(struct aead_instance *inst)
397{
398 struct authenc_esn_instance_ctx *ctx = aead_instance_ctx(inst);
399
400 crypto_drop_skcipher(&ctx->enc);
401 crypto_drop_ahash(&ctx->auth);
402 kfree(inst);
403}
404
405static int crypto_authenc_esn_create(struct crypto_template *tmpl,
406 struct rtattr **tb)
407{
408 struct crypto_attr_type *algt;
409 struct aead_instance *inst;
410 struct hash_alg_common *auth;
411 struct crypto_alg *auth_base;
412 struct skcipher_alg *enc;
413 struct authenc_esn_instance_ctx *ctx;
414 const char *enc_name;
415 int err;
416
417 algt = crypto_get_attr_type(tb);
418 if (IS_ERR(algt))
419 return PTR_ERR(algt);
420
421 if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
422 return -EINVAL;
423
424 auth = ahash_attr_alg(tb[1], CRYPTO_ALG_TYPE_HASH,
425 CRYPTO_ALG_TYPE_AHASH_MASK |
426 crypto_requires_sync(algt->type, algt->mask));
427 if (IS_ERR(auth))
428 return PTR_ERR(auth);
429
430 auth_base = &auth->base;
431
432 enc_name = crypto_attr_alg_name(tb[2]);
433 err = PTR_ERR(enc_name);
434 if (IS_ERR(enc_name))
435 goto out_put_auth;
436
437 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
438 err = -ENOMEM;
439 if (!inst)
440 goto out_put_auth;
441
442 ctx = aead_instance_ctx(inst);
443
444 err = crypto_init_ahash_spawn(&ctx->auth, auth,
445 aead_crypto_instance(inst));
446 if (err)
447 goto err_free_inst;
448
449 crypto_set_skcipher_spawn(&ctx->enc, aead_crypto_instance(inst));
450 err = crypto_grab_skcipher(&ctx->enc, enc_name, 0,
451 crypto_requires_sync(algt->type,
452 algt->mask));
453 if (err)
454 goto err_drop_auth;
455
456 enc = crypto_spawn_skcipher_alg(&ctx->enc);
457
458 err = -ENAMETOOLONG;
459 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
460 "authencesn(%s,%s)", auth_base->cra_name,
461 enc->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
462 goto err_drop_enc;
463
464 if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
465 "authencesn(%s,%s)", auth_base->cra_driver_name,
466 enc->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
467 goto err_drop_enc;
468
469 inst->alg.base.cra_flags = (auth_base->cra_flags |
470 enc->base.cra_flags) & CRYPTO_ALG_ASYNC;
471 inst->alg.base.cra_priority = enc->base.cra_priority * 10 +
472 auth_base->cra_priority;
473 inst->alg.base.cra_blocksize = enc->base.cra_blocksize;
474 inst->alg.base.cra_alignmask = auth_base->cra_alignmask |
475 enc->base.cra_alignmask;
476 inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_esn_ctx);
477
478 inst->alg.ivsize = crypto_skcipher_alg_ivsize(enc);
479 inst->alg.chunksize = crypto_skcipher_alg_chunksize(enc);
480 inst->alg.maxauthsize = auth->digestsize;
481
482 inst->alg.init = crypto_authenc_esn_init_tfm;
483 inst->alg.exit = crypto_authenc_esn_exit_tfm;
484
485 inst->alg.setkey = crypto_authenc_esn_setkey;
486 inst->alg.setauthsize = crypto_authenc_esn_setauthsize;
487 inst->alg.encrypt = crypto_authenc_esn_encrypt;
488 inst->alg.decrypt = crypto_authenc_esn_decrypt;
489
490 inst->free = crypto_authenc_esn_free,
491
492 err = aead_register_instance(tmpl, inst);
493 if (err)
494 goto err_drop_enc;
495
496out:
497 crypto_mod_put(auth_base);
498 return err;
499
500err_drop_enc:
501 crypto_drop_skcipher(&ctx->enc);
502err_drop_auth:
503 crypto_drop_ahash(&ctx->auth);
504err_free_inst:
505 kfree(inst);
506out_put_auth:
507 goto out;
508}
509
510static struct crypto_template crypto_authenc_esn_tmpl = {
511 .name = "authencesn",
512 .create = crypto_authenc_esn_create,
513 .module = THIS_MODULE,
514};
515
516static int __init crypto_authenc_esn_module_init(void)
517{
518 return crypto_register_template(&crypto_authenc_esn_tmpl);
519}
520
521static void __exit crypto_authenc_esn_module_exit(void)
522{
523 crypto_unregister_template(&crypto_authenc_esn_tmpl);
524}
525
526module_init(crypto_authenc_esn_module_init);
527module_exit(crypto_authenc_esn_module_exit);
528
529MODULE_LICENSE("GPL");
530MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
531MODULE_DESCRIPTION("AEAD wrapper for IPsec with extended sequence numbers");
532MODULE_ALIAS_CRYPTO("authencesn");
533