1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31#include <crypto/authenc.h>
32#include <crypto/internal/aead.h>
33#include <crypto/internal/hash.h>
34#include <crypto/internal/skcipher.h>
35#include <crypto/scatterwalk.h>
36#include <linux/module.h>
37
38#include "internal.h"
39
40struct essiv_instance_ctx {
41 union {
42 struct crypto_skcipher_spawn skcipher_spawn;
43 struct crypto_aead_spawn aead_spawn;
44 } u;
45 char essiv_cipher_name[CRYPTO_MAX_ALG_NAME];
46 char shash_driver_name[CRYPTO_MAX_ALG_NAME];
47};
48
49struct essiv_tfm_ctx {
50 union {
51 struct crypto_skcipher *skcipher;
52 struct crypto_aead *aead;
53 } u;
54 struct crypto_cipher *essiv_cipher;
55 struct crypto_shash *hash;
56 int ivoffset;
57};
58
59struct essiv_aead_request_ctx {
60 struct scatterlist sg[4];
61 u8 *assoc;
62 struct aead_request aead_req;
63};
64
65static int essiv_skcipher_setkey(struct crypto_skcipher *tfm,
66 const u8 *key, unsigned int keylen)
67{
68 struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
69 SHASH_DESC_ON_STACK(desc, tctx->hash);
70 u8 salt[HASH_MAX_DIGESTSIZE];
71 int err;
72
73 crypto_skcipher_clear_flags(tctx->u.skcipher, CRYPTO_TFM_REQ_MASK);
74 crypto_skcipher_set_flags(tctx->u.skcipher,
75 crypto_skcipher_get_flags(tfm) &
76 CRYPTO_TFM_REQ_MASK);
77 err = crypto_skcipher_setkey(tctx->u.skcipher, key, keylen);
78 crypto_skcipher_set_flags(tfm,
79 crypto_skcipher_get_flags(tctx->u.skcipher) &
80 CRYPTO_TFM_RES_MASK);
81 if (err)
82 return err;
83
84 desc->tfm = tctx->hash;
85 err = crypto_shash_digest(desc, key, keylen, salt);
86 if (err)
87 return err;
88
89 crypto_cipher_clear_flags(tctx->essiv_cipher, CRYPTO_TFM_REQ_MASK);
90 crypto_cipher_set_flags(tctx->essiv_cipher,
91 crypto_skcipher_get_flags(tfm) &
92 CRYPTO_TFM_REQ_MASK);
93 err = crypto_cipher_setkey(tctx->essiv_cipher, salt,
94 crypto_shash_digestsize(tctx->hash));
95 crypto_skcipher_set_flags(tfm,
96 crypto_cipher_get_flags(tctx->essiv_cipher) &
97 CRYPTO_TFM_RES_MASK);
98
99 return err;
100}
101
102static int essiv_aead_setkey(struct crypto_aead *tfm, const u8 *key,
103 unsigned int keylen)
104{
105 struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
106 SHASH_DESC_ON_STACK(desc, tctx->hash);
107 struct crypto_authenc_keys keys;
108 u8 salt[HASH_MAX_DIGESTSIZE];
109 int err;
110
111 crypto_aead_clear_flags(tctx->u.aead, CRYPTO_TFM_REQ_MASK);
112 crypto_aead_set_flags(tctx->u.aead, crypto_aead_get_flags(tfm) &
113 CRYPTO_TFM_REQ_MASK);
114 err = crypto_aead_setkey(tctx->u.aead, key, keylen);
115 crypto_aead_set_flags(tfm, crypto_aead_get_flags(tctx->u.aead) &
116 CRYPTO_TFM_RES_MASK);
117 if (err)
118 return err;
119
120 if (crypto_authenc_extractkeys(&keys, key, keylen) != 0) {
121 crypto_aead_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
122 return -EINVAL;
123 }
124
125 desc->tfm = tctx->hash;
126 err = crypto_shash_init(desc) ?:
127 crypto_shash_update(desc, keys.enckey, keys.enckeylen) ?:
128 crypto_shash_finup(desc, keys.authkey, keys.authkeylen, salt);
129 if (err)
130 return err;
131
132 crypto_cipher_clear_flags(tctx->essiv_cipher, CRYPTO_TFM_REQ_MASK);
133 crypto_cipher_set_flags(tctx->essiv_cipher, crypto_aead_get_flags(tfm) &
134 CRYPTO_TFM_REQ_MASK);
135 err = crypto_cipher_setkey(tctx->essiv_cipher, salt,
136 crypto_shash_digestsize(tctx->hash));
137 crypto_aead_set_flags(tfm, crypto_cipher_get_flags(tctx->essiv_cipher) &
138 CRYPTO_TFM_RES_MASK);
139
140 return err;
141}
142
143static int essiv_aead_setauthsize(struct crypto_aead *tfm,
144 unsigned int authsize)
145{
146 struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
147
148 return crypto_aead_setauthsize(tctx->u.aead, authsize);
149}
150
151static void essiv_skcipher_done(struct crypto_async_request *areq, int err)
152{
153 struct skcipher_request *req = areq->data;
154
155 skcipher_request_complete(req, err);
156}
157
158static int essiv_skcipher_crypt(struct skcipher_request *req, bool enc)
159{
160 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
161 const struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
162 struct skcipher_request *subreq = skcipher_request_ctx(req);
163
164 crypto_cipher_encrypt_one(tctx->essiv_cipher, req->iv, req->iv);
165
166 skcipher_request_set_tfm(subreq, tctx->u.skcipher);
167 skcipher_request_set_crypt(subreq, req->src, req->dst, req->cryptlen,
168 req->iv);
169 skcipher_request_set_callback(subreq, skcipher_request_flags(req),
170 essiv_skcipher_done, req);
171
172 return enc ? crypto_skcipher_encrypt(subreq) :
173 crypto_skcipher_decrypt(subreq);
174}
175
176static int essiv_skcipher_encrypt(struct skcipher_request *req)
177{
178 return essiv_skcipher_crypt(req, true);
179}
180
181static int essiv_skcipher_decrypt(struct skcipher_request *req)
182{
183 return essiv_skcipher_crypt(req, false);
184}
185
186static void essiv_aead_done(struct crypto_async_request *areq, int err)
187{
188 struct aead_request *req = areq->data;
189 struct essiv_aead_request_ctx *rctx = aead_request_ctx(req);
190
191 kfree(rctx->assoc);
192 aead_request_complete(req, err);
193}
194
195static int essiv_aead_crypt(struct aead_request *req, bool enc)
196{
197 struct crypto_aead *tfm = crypto_aead_reqtfm(req);
198 const struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
199 struct essiv_aead_request_ctx *rctx = aead_request_ctx(req);
200 struct aead_request *subreq = &rctx->aead_req;
201 struct scatterlist *src = req->src;
202 int err;
203
204 crypto_cipher_encrypt_one(tctx->essiv_cipher, req->iv, req->iv);
205
206
207
208
209
210
211 rctx->assoc = NULL;
212 if (req->src == req->dst || !enc) {
213 scatterwalk_map_and_copy(req->iv, req->dst,
214 req->assoclen - crypto_aead_ivsize(tfm),
215 crypto_aead_ivsize(tfm), 1);
216 } else {
217 u8 *iv = (u8 *)aead_request_ctx(req) + tctx->ivoffset;
218 int ivsize = crypto_aead_ivsize(tfm);
219 int ssize = req->assoclen - ivsize;
220 struct scatterlist *sg;
221 int nents;
222
223 if (ssize < 0)
224 return -EINVAL;
225
226 nents = sg_nents_for_len(req->src, ssize);
227 if (nents < 0)
228 return -EINVAL;
229
230 memcpy(iv, req->iv, ivsize);
231 sg_init_table(rctx->sg, 4);
232
233 if (unlikely(nents > 1)) {
234
235
236
237
238 rctx->assoc = kmalloc(ssize, GFP_ATOMIC);
239 if (!rctx->assoc)
240 return -ENOMEM;
241
242 scatterwalk_map_and_copy(rctx->assoc, req->src, 0,
243 ssize, 0);
244 sg_set_buf(rctx->sg, rctx->assoc, ssize);
245 } else {
246 sg_set_page(rctx->sg, sg_page(req->src), ssize,
247 req->src->offset);
248 }
249
250 sg_set_buf(rctx->sg + 1, iv, ivsize);
251 sg = scatterwalk_ffwd(rctx->sg + 2, req->src, req->assoclen);
252 if (sg != rctx->sg + 2)
253 sg_chain(rctx->sg, 3, sg);
254
255 src = rctx->sg;
256 }
257
258 aead_request_set_tfm(subreq, tctx->u.aead);
259 aead_request_set_ad(subreq, req->assoclen);
260 aead_request_set_callback(subreq, aead_request_flags(req),
261 essiv_aead_done, req);
262 aead_request_set_crypt(subreq, src, req->dst, req->cryptlen, req->iv);
263
264 err = enc ? crypto_aead_encrypt(subreq) :
265 crypto_aead_decrypt(subreq);
266
267 if (rctx->assoc && err != -EINPROGRESS)
268 kfree(rctx->assoc);
269 return err;
270}
271
272static int essiv_aead_encrypt(struct aead_request *req)
273{
274 return essiv_aead_crypt(req, true);
275}
276
277static int essiv_aead_decrypt(struct aead_request *req)
278{
279 return essiv_aead_crypt(req, false);
280}
281
282static int essiv_init_tfm(struct essiv_instance_ctx *ictx,
283 struct essiv_tfm_ctx *tctx)
284{
285 struct crypto_cipher *essiv_cipher;
286 struct crypto_shash *hash;
287 int err;
288
289 essiv_cipher = crypto_alloc_cipher(ictx->essiv_cipher_name, 0, 0);
290 if (IS_ERR(essiv_cipher))
291 return PTR_ERR(essiv_cipher);
292
293 hash = crypto_alloc_shash(ictx->shash_driver_name, 0, 0);
294 if (IS_ERR(hash)) {
295 err = PTR_ERR(hash);
296 goto err_free_essiv_cipher;
297 }
298
299 tctx->essiv_cipher = essiv_cipher;
300 tctx->hash = hash;
301
302 return 0;
303
304err_free_essiv_cipher:
305 crypto_free_cipher(essiv_cipher);
306 return err;
307}
308
309static int essiv_skcipher_init_tfm(struct crypto_skcipher *tfm)
310{
311 struct skcipher_instance *inst = skcipher_alg_instance(tfm);
312 struct essiv_instance_ctx *ictx = skcipher_instance_ctx(inst);
313 struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
314 struct crypto_skcipher *skcipher;
315 int err;
316
317 skcipher = crypto_spawn_skcipher(&ictx->u.skcipher_spawn);
318 if (IS_ERR(skcipher))
319 return PTR_ERR(skcipher);
320
321 crypto_skcipher_set_reqsize(tfm, sizeof(struct skcipher_request) +
322 crypto_skcipher_reqsize(skcipher));
323
324 err = essiv_init_tfm(ictx, tctx);
325 if (err) {
326 crypto_free_skcipher(skcipher);
327 return err;
328 }
329
330 tctx->u.skcipher = skcipher;
331 return 0;
332}
333
334static int essiv_aead_init_tfm(struct crypto_aead *tfm)
335{
336 struct aead_instance *inst = aead_alg_instance(tfm);
337 struct essiv_instance_ctx *ictx = aead_instance_ctx(inst);
338 struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
339 struct crypto_aead *aead;
340 unsigned int subreq_size;
341 int err;
342
343 BUILD_BUG_ON(offsetofend(struct essiv_aead_request_ctx, aead_req) !=
344 sizeof(struct essiv_aead_request_ctx));
345
346 aead = crypto_spawn_aead(&ictx->u.aead_spawn);
347 if (IS_ERR(aead))
348 return PTR_ERR(aead);
349
350 subreq_size = sizeof_field(struct essiv_aead_request_ctx, aead_req) +
351 crypto_aead_reqsize(aead);
352
353 tctx->ivoffset = offsetof(struct essiv_aead_request_ctx, aead_req) +
354 subreq_size;
355 crypto_aead_set_reqsize(tfm, tctx->ivoffset + crypto_aead_ivsize(aead));
356
357 err = essiv_init_tfm(ictx, tctx);
358 if (err) {
359 crypto_free_aead(aead);
360 return err;
361 }
362
363 tctx->u.aead = aead;
364 return 0;
365}
366
367static void essiv_skcipher_exit_tfm(struct crypto_skcipher *tfm)
368{
369 struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
370
371 crypto_free_skcipher(tctx->u.skcipher);
372 crypto_free_cipher(tctx->essiv_cipher);
373 crypto_free_shash(tctx->hash);
374}
375
376static void essiv_aead_exit_tfm(struct crypto_aead *tfm)
377{
378 struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
379
380 crypto_free_aead(tctx->u.aead);
381 crypto_free_cipher(tctx->essiv_cipher);
382 crypto_free_shash(tctx->hash);
383}
384
385static void essiv_skcipher_free_instance(struct skcipher_instance *inst)
386{
387 struct essiv_instance_ctx *ictx = skcipher_instance_ctx(inst);
388
389 crypto_drop_skcipher(&ictx->u.skcipher_spawn);
390 kfree(inst);
391}
392
393static void essiv_aead_free_instance(struct aead_instance *inst)
394{
395 struct essiv_instance_ctx *ictx = aead_instance_ctx(inst);
396
397 crypto_drop_aead(&ictx->u.aead_spawn);
398 kfree(inst);
399}
400
401static bool parse_cipher_name(char *essiv_cipher_name, const char *cra_name)
402{
403 const char *p, *q;
404 int len;
405
406
407 p = strrchr(cra_name, '(');
408 if (!p++)
409 return false;
410
411
412 q = strchr(p, ')');
413 if (!q)
414 return false;
415
416 len = q - p;
417 if (len >= CRYPTO_MAX_ALG_NAME)
418 return false;
419
420 memcpy(essiv_cipher_name, p, len);
421 essiv_cipher_name[len] = '\0';
422 return true;
423}
424
425static bool essiv_supported_algorithms(const char *essiv_cipher_name,
426 struct shash_alg *hash_alg,
427 int ivsize)
428{
429 struct crypto_alg *alg;
430 bool ret = false;
431
432 alg = crypto_alg_mod_lookup(essiv_cipher_name,
433 CRYPTO_ALG_TYPE_CIPHER,
434 CRYPTO_ALG_TYPE_MASK);
435 if (IS_ERR(alg))
436 return false;
437
438 if (hash_alg->digestsize < alg->cra_cipher.cia_min_keysize ||
439 hash_alg->digestsize > alg->cra_cipher.cia_max_keysize)
440 goto out;
441
442 if (ivsize != alg->cra_blocksize)
443 goto out;
444
445 if (crypto_shash_alg_has_setkey(hash_alg))
446 goto out;
447
448 ret = true;
449
450out:
451 crypto_mod_put(alg);
452 return ret;
453}
454
455static int essiv_create(struct crypto_template *tmpl, struct rtattr **tb)
456{
457 struct crypto_attr_type *algt;
458 const char *inner_cipher_name;
459 const char *shash_name;
460 struct skcipher_instance *skcipher_inst = NULL;
461 struct aead_instance *aead_inst = NULL;
462 struct crypto_instance *inst;
463 struct crypto_alg *base, *block_base;
464 struct essiv_instance_ctx *ictx;
465 struct skcipher_alg *skcipher_alg = NULL;
466 struct aead_alg *aead_alg = NULL;
467 struct crypto_alg *_hash_alg;
468 struct shash_alg *hash_alg;
469 int ivsize;
470 u32 type;
471 int err;
472
473 algt = crypto_get_attr_type(tb);
474 if (IS_ERR(algt))
475 return PTR_ERR(algt);
476
477 inner_cipher_name = crypto_attr_alg_name(tb[1]);
478 if (IS_ERR(inner_cipher_name))
479 return PTR_ERR(inner_cipher_name);
480
481 shash_name = crypto_attr_alg_name(tb[2]);
482 if (IS_ERR(shash_name))
483 return PTR_ERR(shash_name);
484
485 type = algt->type & algt->mask;
486
487 switch (type) {
488 case CRYPTO_ALG_TYPE_SKCIPHER:
489 skcipher_inst = kzalloc(sizeof(*skcipher_inst) +
490 sizeof(*ictx), GFP_KERNEL);
491 if (!skcipher_inst)
492 return -ENOMEM;
493 inst = skcipher_crypto_instance(skcipher_inst);
494 base = &skcipher_inst->alg.base;
495 ictx = crypto_instance_ctx(inst);
496
497
498 crypto_set_skcipher_spawn(&ictx->u.skcipher_spawn, inst);
499 err = crypto_grab_skcipher(&ictx->u.skcipher_spawn,
500 inner_cipher_name, 0,
501 crypto_requires_sync(algt->type,
502 algt->mask));
503 if (err)
504 goto out_free_inst;
505 skcipher_alg = crypto_spawn_skcipher_alg(&ictx->u.skcipher_spawn);
506 block_base = &skcipher_alg->base;
507 ivsize = crypto_skcipher_alg_ivsize(skcipher_alg);
508 break;
509
510 case CRYPTO_ALG_TYPE_AEAD:
511 aead_inst = kzalloc(sizeof(*aead_inst) +
512 sizeof(*ictx), GFP_KERNEL);
513 if (!aead_inst)
514 return -ENOMEM;
515 inst = aead_crypto_instance(aead_inst);
516 base = &aead_inst->alg.base;
517 ictx = crypto_instance_ctx(inst);
518
519
520 crypto_set_aead_spawn(&ictx->u.aead_spawn, inst);
521 err = crypto_grab_aead(&ictx->u.aead_spawn,
522 inner_cipher_name, 0,
523 crypto_requires_sync(algt->type,
524 algt->mask));
525 if (err)
526 goto out_free_inst;
527 aead_alg = crypto_spawn_aead_alg(&ictx->u.aead_spawn);
528 block_base = &aead_alg->base;
529 if (!strstarts(block_base->cra_name, "authenc(")) {
530 pr_warn("Only authenc() type AEADs are supported by ESSIV\n");
531 err = -EINVAL;
532 goto out_drop_skcipher;
533 }
534 ivsize = aead_alg->ivsize;
535 break;
536
537 default:
538 return -EINVAL;
539 }
540
541 if (!parse_cipher_name(ictx->essiv_cipher_name, block_base->cra_name)) {
542 pr_warn("Failed to parse ESSIV cipher name from skcipher cra_name\n");
543 err = -EINVAL;
544 goto out_drop_skcipher;
545 }
546
547
548 _hash_alg = crypto_alg_mod_lookup(shash_name,
549 CRYPTO_ALG_TYPE_SHASH,
550 CRYPTO_ALG_TYPE_MASK);
551 if (IS_ERR(_hash_alg)) {
552 err = PTR_ERR(_hash_alg);
553 goto out_drop_skcipher;
554 }
555 hash_alg = __crypto_shash_alg(_hash_alg);
556
557
558 if (!essiv_supported_algorithms(ictx->essiv_cipher_name, hash_alg,
559 ivsize)) {
560 pr_warn("Unsupported essiv instantiation: essiv(%s,%s)\n",
561 block_base->cra_name, hash_alg->base.cra_name);
562 err = -EINVAL;
563 goto out_free_hash;
564 }
565
566
567 strlcpy(ictx->shash_driver_name, hash_alg->base.cra_driver_name,
568 CRYPTO_MAX_ALG_NAME);
569
570
571
572 err = -ENAMETOOLONG;
573 if (snprintf(base->cra_name, CRYPTO_MAX_ALG_NAME,
574 "essiv(%s,%s)", block_base->cra_name,
575 hash_alg->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
576 goto out_free_hash;
577 if (snprintf(base->cra_driver_name, CRYPTO_MAX_ALG_NAME,
578 "essiv(%s,%s)", block_base->cra_driver_name,
579 hash_alg->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
580 goto out_free_hash;
581
582 base->cra_flags = block_base->cra_flags & CRYPTO_ALG_ASYNC;
583 base->cra_blocksize = block_base->cra_blocksize;
584 base->cra_ctxsize = sizeof(struct essiv_tfm_ctx);
585 base->cra_alignmask = block_base->cra_alignmask;
586 base->cra_priority = block_base->cra_priority;
587
588 if (type == CRYPTO_ALG_TYPE_SKCIPHER) {
589 skcipher_inst->alg.setkey = essiv_skcipher_setkey;
590 skcipher_inst->alg.encrypt = essiv_skcipher_encrypt;
591 skcipher_inst->alg.decrypt = essiv_skcipher_decrypt;
592 skcipher_inst->alg.init = essiv_skcipher_init_tfm;
593 skcipher_inst->alg.exit = essiv_skcipher_exit_tfm;
594
595 skcipher_inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(skcipher_alg);
596 skcipher_inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(skcipher_alg);
597 skcipher_inst->alg.ivsize = ivsize;
598 skcipher_inst->alg.chunksize = crypto_skcipher_alg_chunksize(skcipher_alg);
599 skcipher_inst->alg.walksize = crypto_skcipher_alg_walksize(skcipher_alg);
600
601 skcipher_inst->free = essiv_skcipher_free_instance;
602
603 err = skcipher_register_instance(tmpl, skcipher_inst);
604 } else {
605 aead_inst->alg.setkey = essiv_aead_setkey;
606 aead_inst->alg.setauthsize = essiv_aead_setauthsize;
607 aead_inst->alg.encrypt = essiv_aead_encrypt;
608 aead_inst->alg.decrypt = essiv_aead_decrypt;
609 aead_inst->alg.init = essiv_aead_init_tfm;
610 aead_inst->alg.exit = essiv_aead_exit_tfm;
611
612 aead_inst->alg.ivsize = ivsize;
613 aead_inst->alg.maxauthsize = crypto_aead_alg_maxauthsize(aead_alg);
614 aead_inst->alg.chunksize = crypto_aead_alg_chunksize(aead_alg);
615
616 aead_inst->free = essiv_aead_free_instance;
617
618 err = aead_register_instance(tmpl, aead_inst);
619 }
620
621 if (err)
622 goto out_free_hash;
623
624 crypto_mod_put(_hash_alg);
625 return 0;
626
627out_free_hash:
628 crypto_mod_put(_hash_alg);
629out_drop_skcipher:
630 if (type == CRYPTO_ALG_TYPE_SKCIPHER)
631 crypto_drop_skcipher(&ictx->u.skcipher_spawn);
632 else
633 crypto_drop_aead(&ictx->u.aead_spawn);
634out_free_inst:
635 kfree(skcipher_inst);
636 kfree(aead_inst);
637 return err;
638}
639
640
641static struct crypto_template essiv_tmpl = {
642 .name = "essiv",
643 .create = essiv_create,
644 .module = THIS_MODULE,
645};
646
647static int __init essiv_module_init(void)
648{
649 return crypto_register_template(&essiv_tmpl);
650}
651
652static void __exit essiv_module_exit(void)
653{
654 crypto_unregister_template(&essiv_tmpl);
655}
656
657subsys_initcall(essiv_module_init);
658module_exit(essiv_module_exit);
659
660MODULE_DESCRIPTION("ESSIV skcipher/aead wrapper for block encryption");
661MODULE_LICENSE("GPL v2");
662MODULE_ALIAS_CRYPTO("essiv");
663
