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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 if (rctx->assoc)
192 kfree(rctx->assoc);
193 aead_request_complete(req, err);
194}
195
196static int essiv_aead_crypt(struct aead_request *req, bool enc)
197{
198 struct crypto_aead *tfm = crypto_aead_reqtfm(req);
199 const struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
200 struct essiv_aead_request_ctx *rctx = aead_request_ctx(req);
201 struct aead_request *subreq = &rctx->aead_req;
202 struct scatterlist *src = req->src;
203 int err;
204
205 crypto_cipher_encrypt_one(tctx->essiv_cipher, req->iv, req->iv);
206
207
208
209
210
211
212 rctx->assoc = NULL;
213 if (req->src == req->dst || !enc) {
214 scatterwalk_map_and_copy(req->iv, req->dst,
215 req->assoclen - crypto_aead_ivsize(tfm),
216 crypto_aead_ivsize(tfm), 1);
217 } else {
218 u8 *iv = (u8 *)aead_request_ctx(req) + tctx->ivoffset;
219 int ivsize = crypto_aead_ivsize(tfm);
220 int ssize = req->assoclen - ivsize;
221 struct scatterlist *sg;
222 int nents;
223
224 if (ssize < 0)
225 return -EINVAL;
226
227 nents = sg_nents_for_len(req->src, ssize);
228 if (nents < 0)
229 return -EINVAL;
230
231 memcpy(iv, req->iv, ivsize);
232 sg_init_table(rctx->sg, 4);
233
234 if (unlikely(nents > 1)) {
235
236
237
238
239 rctx->assoc = kmalloc(ssize, GFP_ATOMIC);
240 if (!rctx->assoc)
241 return -ENOMEM;
242
243 scatterwalk_map_and_copy(rctx->assoc, req->src, 0,
244 ssize, 0);
245 sg_set_buf(rctx->sg, rctx->assoc, ssize);
246 } else {
247 sg_set_page(rctx->sg, sg_page(req->src), ssize,
248 req->src->offset);
249 }
250
251 sg_set_buf(rctx->sg + 1, iv, ivsize);
252 sg = scatterwalk_ffwd(rctx->sg + 2, req->src, req->assoclen);
253 if (sg != rctx->sg + 2)
254 sg_chain(rctx->sg, 3, sg);
255
256 src = rctx->sg;
257 }
258
259 aead_request_set_tfm(subreq, tctx->u.aead);
260 aead_request_set_ad(subreq, req->assoclen);
261 aead_request_set_callback(subreq, aead_request_flags(req),
262 essiv_aead_done, req);
263 aead_request_set_crypt(subreq, src, req->dst, req->cryptlen, req->iv);
264
265 err = enc ? crypto_aead_encrypt(subreq) :
266 crypto_aead_decrypt(subreq);
267
268 if (rctx->assoc && err != -EINPROGRESS)
269 kfree(rctx->assoc);
270 return err;
271}
272
273static int essiv_aead_encrypt(struct aead_request *req)
274{
275 return essiv_aead_crypt(req, true);
276}
277
278static int essiv_aead_decrypt(struct aead_request *req)
279{
280 return essiv_aead_crypt(req, false);
281}
282
283static int essiv_init_tfm(struct essiv_instance_ctx *ictx,
284 struct essiv_tfm_ctx *tctx)
285{
286 struct crypto_cipher *essiv_cipher;
287 struct crypto_shash *hash;
288 int err;
289
290 essiv_cipher = crypto_alloc_cipher(ictx->essiv_cipher_name, 0, 0);
291 if (IS_ERR(essiv_cipher))
292 return PTR_ERR(essiv_cipher);
293
294 hash = crypto_alloc_shash(ictx->shash_driver_name, 0, 0);
295 if (IS_ERR(hash)) {
296 err = PTR_ERR(hash);
297 goto err_free_essiv_cipher;
298 }
299
300 tctx->essiv_cipher = essiv_cipher;
301 tctx->hash = hash;
302
303 return 0;
304
305err_free_essiv_cipher:
306 crypto_free_cipher(essiv_cipher);
307 return err;
308}
309
310static int essiv_skcipher_init_tfm(struct crypto_skcipher *tfm)
311{
312 struct skcipher_instance *inst = skcipher_alg_instance(tfm);
313 struct essiv_instance_ctx *ictx = skcipher_instance_ctx(inst);
314 struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
315 struct crypto_skcipher *skcipher;
316 int err;
317
318 skcipher = crypto_spawn_skcipher(&ictx->u.skcipher_spawn);
319 if (IS_ERR(skcipher))
320 return PTR_ERR(skcipher);
321
322 crypto_skcipher_set_reqsize(tfm, sizeof(struct skcipher_request) +
323 crypto_skcipher_reqsize(skcipher));
324
325 err = essiv_init_tfm(ictx, tctx);
326 if (err) {
327 crypto_free_skcipher(skcipher);
328 return err;
329 }
330
331 tctx->u.skcipher = skcipher;
332 return 0;
333}
334
335static int essiv_aead_init_tfm(struct crypto_aead *tfm)
336{
337 struct aead_instance *inst = aead_alg_instance(tfm);
338 struct essiv_instance_ctx *ictx = aead_instance_ctx(inst);
339 struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
340 struct crypto_aead *aead;
341 unsigned int subreq_size;
342 int err;
343
344 BUILD_BUG_ON(offsetofend(struct essiv_aead_request_ctx, aead_req) !=
345 sizeof(struct essiv_aead_request_ctx));
346
347 aead = crypto_spawn_aead(&ictx->u.aead_spawn);
348 if (IS_ERR(aead))
349 return PTR_ERR(aead);
350
351 subreq_size = FIELD_SIZEOF(struct essiv_aead_request_ctx, aead_req) +
352 crypto_aead_reqsize(aead);
353
354 tctx->ivoffset = offsetof(struct essiv_aead_request_ctx, aead_req) +
355 subreq_size;
356 crypto_aead_set_reqsize(tfm, tctx->ivoffset + crypto_aead_ivsize(aead));
357
358 err = essiv_init_tfm(ictx, tctx);
359 if (err) {
360 crypto_free_aead(aead);
361 return err;
362 }
363
364 tctx->u.aead = aead;
365 return 0;
366}
367
368static void essiv_skcipher_exit_tfm(struct crypto_skcipher *tfm)
369{
370 struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
371
372 crypto_free_skcipher(tctx->u.skcipher);
373 crypto_free_cipher(tctx->essiv_cipher);
374 crypto_free_shash(tctx->hash);
375}
376
377static void essiv_aead_exit_tfm(struct crypto_aead *tfm)
378{
379 struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
380
381 crypto_free_aead(tctx->u.aead);
382 crypto_free_cipher(tctx->essiv_cipher);
383 crypto_free_shash(tctx->hash);
384}
385
386static void essiv_skcipher_free_instance(struct skcipher_instance *inst)
387{
388 struct essiv_instance_ctx *ictx = skcipher_instance_ctx(inst);
389
390 crypto_drop_skcipher(&ictx->u.skcipher_spawn);
391 kfree(inst);
392}
393
394static void essiv_aead_free_instance(struct aead_instance *inst)
395{
396 struct essiv_instance_ctx *ictx = aead_instance_ctx(inst);
397
398 crypto_drop_aead(&ictx->u.aead_spawn);
399 kfree(inst);
400}
401
402static bool parse_cipher_name(char *essiv_cipher_name, const char *cra_name)
403{
404 const char *p, *q;
405 int len;
406
407
408 p = strrchr(cra_name, '(');
409 if (!p++)
410 return false;
411
412
413 q = strchr(p, ')');
414 if (!q)
415 return false;
416
417 len = q - p;
418 if (len >= CRYPTO_MAX_ALG_NAME)
419 return false;
420
421 memcpy(essiv_cipher_name, p, len);
422 essiv_cipher_name[len] = '\0';
423 return true;
424}
425
426static bool essiv_supported_algorithms(const char *essiv_cipher_name,
427 struct shash_alg *hash_alg,
428 int ivsize)
429{
430 struct crypto_alg *alg;
431 bool ret = false;
432
433 alg = crypto_alg_mod_lookup(essiv_cipher_name,
434 CRYPTO_ALG_TYPE_CIPHER,
435 CRYPTO_ALG_TYPE_MASK);
436 if (IS_ERR(alg))
437 return false;
438
439 if (hash_alg->digestsize < alg->cra_cipher.cia_min_keysize ||
440 hash_alg->digestsize > alg->cra_cipher.cia_max_keysize)
441 goto out;
442
443 if (ivsize != alg->cra_blocksize)
444 goto out;
445
446 if (crypto_shash_alg_has_setkey(hash_alg))
447 goto out;
448
449 ret = true;
450
451out:
452 crypto_mod_put(alg);
453 return ret;
454}
455
456static int essiv_create(struct crypto_template *tmpl, struct rtattr **tb)
457{
458 struct crypto_attr_type *algt;
459 const char *inner_cipher_name;
460 const char *shash_name;
461 struct skcipher_instance *skcipher_inst = NULL;
462 struct aead_instance *aead_inst = NULL;
463 struct crypto_instance *inst;
464 struct crypto_alg *base, *block_base;
465 struct essiv_instance_ctx *ictx;
466 struct skcipher_alg *skcipher_alg = NULL;
467 struct aead_alg *aead_alg = NULL;
468 struct crypto_alg *_hash_alg;
469 struct shash_alg *hash_alg;
470 int ivsize;
471 u32 type;
472 int err;
473
474 algt = crypto_get_attr_type(tb);
475 if (IS_ERR(algt))
476 return PTR_ERR(algt);
477
478 inner_cipher_name = crypto_attr_alg_name(tb[1]);
479 if (IS_ERR(inner_cipher_name))
480 return PTR_ERR(inner_cipher_name);
481
482 shash_name = crypto_attr_alg_name(tb[2]);
483 if (IS_ERR(shash_name))
484 return PTR_ERR(shash_name);
485
486 type = algt->type & algt->mask;
487
488 switch (type) {
489 case CRYPTO_ALG_TYPE_BLKCIPHER:
490 skcipher_inst = kzalloc(sizeof(*skcipher_inst) +
491 sizeof(*ictx), GFP_KERNEL);
492 if (!skcipher_inst)
493 return -ENOMEM;
494 inst = skcipher_crypto_instance(skcipher_inst);
495 base = &skcipher_inst->alg.base;
496 ictx = crypto_instance_ctx(inst);
497
498
499 crypto_set_skcipher_spawn(&ictx->u.skcipher_spawn, inst);
500 err = crypto_grab_skcipher(&ictx->u.skcipher_spawn,
501 inner_cipher_name, 0,
502 crypto_requires_sync(algt->type,
503 algt->mask));
504 if (err)
505 goto out_free_inst;
506 skcipher_alg = crypto_spawn_skcipher_alg(&ictx->u.skcipher_spawn);
507 block_base = &skcipher_alg->base;
508 ivsize = crypto_skcipher_alg_ivsize(skcipher_alg);
509 break;
510
511 case CRYPTO_ALG_TYPE_AEAD:
512 aead_inst = kzalloc(sizeof(*aead_inst) +
513 sizeof(*ictx), GFP_KERNEL);
514 if (!aead_inst)
515 return -ENOMEM;
516 inst = aead_crypto_instance(aead_inst);
517 base = &aead_inst->alg.base;
518 ictx = crypto_instance_ctx(inst);
519
520
521 crypto_set_aead_spawn(&ictx->u.aead_spawn, inst);
522 err = crypto_grab_aead(&ictx->u.aead_spawn,
523 inner_cipher_name, 0,
524 crypto_requires_sync(algt->type,
525 algt->mask));
526 if (err)
527 goto out_free_inst;
528 aead_alg = crypto_spawn_aead_alg(&ictx->u.aead_spawn);
529 block_base = &aead_alg->base;
530 if (!strstarts(block_base->cra_name, "authenc(")) {
531 pr_warn("Only authenc() type AEADs are supported by ESSIV\n");
532 err = -EINVAL;
533 goto out_drop_skcipher;
534 }
535 ivsize = aead_alg->ivsize;
536 break;
537
538 default:
539 return -EINVAL;
540 }
541
542 if (!parse_cipher_name(ictx->essiv_cipher_name, block_base->cra_name)) {
543 pr_warn("Failed to parse ESSIV cipher name from skcipher cra_name\n");
544 err = -EINVAL;
545 goto out_drop_skcipher;
546 }
547
548
549 _hash_alg = crypto_alg_mod_lookup(shash_name,
550 CRYPTO_ALG_TYPE_SHASH,
551 CRYPTO_ALG_TYPE_MASK);
552 if (IS_ERR(_hash_alg)) {
553 err = PTR_ERR(_hash_alg);
554 goto out_drop_skcipher;
555 }
556 hash_alg = __crypto_shash_alg(_hash_alg);
557
558
559 if (!essiv_supported_algorithms(ictx->essiv_cipher_name, hash_alg,
560 ivsize)) {
561 pr_warn("Unsupported essiv instantiation: essiv(%s,%s)\n",
562 block_base->cra_name, hash_alg->base.cra_name);
563 err = -EINVAL;
564 goto out_free_hash;
565 }
566
567
568 strlcpy(ictx->shash_driver_name, hash_alg->base.cra_driver_name,
569 CRYPTO_MAX_ALG_NAME);
570
571
572
573 err = -ENAMETOOLONG;
574 if (snprintf(base->cra_name, CRYPTO_MAX_ALG_NAME,
575 "essiv(%s,%s)", block_base->cra_name,
576 hash_alg->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
577 goto out_free_hash;
578 if (snprintf(base->cra_driver_name, CRYPTO_MAX_ALG_NAME,
579 "essiv(%s,%s)", block_base->cra_driver_name,
580 hash_alg->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
581 goto out_free_hash;
582
583 base->cra_flags = block_base->cra_flags & CRYPTO_ALG_ASYNC;
584 base->cra_blocksize = block_base->cra_blocksize;
585 base->cra_ctxsize = sizeof(struct essiv_tfm_ctx);
586 base->cra_alignmask = block_base->cra_alignmask;
587 base->cra_priority = block_base->cra_priority;
588
589 if (type == CRYPTO_ALG_TYPE_BLKCIPHER) {
590 skcipher_inst->alg.setkey = essiv_skcipher_setkey;
591 skcipher_inst->alg.encrypt = essiv_skcipher_encrypt;
592 skcipher_inst->alg.decrypt = essiv_skcipher_decrypt;
593 skcipher_inst->alg.init = essiv_skcipher_init_tfm;
594 skcipher_inst->alg.exit = essiv_skcipher_exit_tfm;
595
596 skcipher_inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(skcipher_alg);
597 skcipher_inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(skcipher_alg);
598 skcipher_inst->alg.ivsize = ivsize;
599 skcipher_inst->alg.chunksize = crypto_skcipher_alg_chunksize(skcipher_alg);
600 skcipher_inst->alg.walksize = crypto_skcipher_alg_walksize(skcipher_alg);
601
602 skcipher_inst->free = essiv_skcipher_free_instance;
603
604 err = skcipher_register_instance(tmpl, skcipher_inst);
605 } else {
606 aead_inst->alg.setkey = essiv_aead_setkey;
607 aead_inst->alg.setauthsize = essiv_aead_setauthsize;
608 aead_inst->alg.encrypt = essiv_aead_encrypt;
609 aead_inst->alg.decrypt = essiv_aead_decrypt;
610 aead_inst->alg.init = essiv_aead_init_tfm;
611 aead_inst->alg.exit = essiv_aead_exit_tfm;
612
613 aead_inst->alg.ivsize = ivsize;
614 aead_inst->alg.maxauthsize = crypto_aead_alg_maxauthsize(aead_alg);
615 aead_inst->alg.chunksize = crypto_aead_alg_chunksize(aead_alg);
616
617 aead_inst->free = essiv_aead_free_instance;
618
619 err = aead_register_instance(tmpl, aead_inst);
620 }
621
622 if (err)
623 goto out_free_hash;
624
625 crypto_mod_put(_hash_alg);
626 return 0;
627
628out_free_hash:
629 crypto_mod_put(_hash_alg);
630out_drop_skcipher:
631 if (type == CRYPTO_ALG_TYPE_BLKCIPHER)
632 crypto_drop_skcipher(&ictx->u.skcipher_spawn);
633 else
634 crypto_drop_aead(&ictx->u.aead_spawn);
635out_free_inst:
636 kfree(skcipher_inst);
637 kfree(aead_inst);
638 return err;
639}
640
641
642static struct crypto_template essiv_tmpl = {
643 .name = "essiv",
644 .create = essiv_create,
645 .module = THIS_MODULE,
646};
647
648static int __init essiv_module_init(void)
649{
650 return crypto_register_template(&essiv_tmpl);
651}
652
653static void __exit essiv_module_exit(void)
654{
655 crypto_unregister_template(&essiv_tmpl);
656}
657
658subsys_initcall(essiv_module_init);
659module_exit(essiv_module_exit);
660
661MODULE_DESCRIPTION("ESSIV skcipher/aead wrapper for block encryption");
662MODULE_LICENSE("GPL v2");
663MODULE_ALIAS_CRYPTO("essiv");
664
