1// SPDX-License-Identifier: GPL-2.0
2/*
3 * ESSIV skcipher and aead template for block encryption
4 *
5 * This template encapsulates the ESSIV IV generation algorithm used by
6 * dm-crypt and fscrypt, which converts the initial vector for the skcipher
7 * used for block encryption, by encrypting it using the hash of the
8 * skcipher key as encryption key. Usually, the input IV is a 64-bit sector
9 * number in LE representation zero-padded to the size of the IV, but this
10 * is not assumed by this driver.
11 *
12 * The typical use of this template is to instantiate the skcipher
13 * 'essiv(cbc(aes),sha256)', which is the only instantiation used by
14 * fscrypt, and the most relevant one for dm-crypt. However, dm-crypt
15 * also permits ESSIV to be used in combination with the authenc template,
16 * e.g., 'essiv(authenc(hmac(sha256),cbc(aes)),sha256)', in which case
17 * we need to instantiate an aead that accepts the same special key format
18 * as the authenc template, and deals with the way the encrypted IV is
19 * embedded into the AAD area of the aead request. This means the AEAD
20 * flavor produced by this template is tightly coupled to the way dm-crypt
21 * happens to use it.
22 *
23 * Copyright (c) 2019 Linaro, Ltd. <ard.biesheuvel@linaro.org>
24 *
25 * Heavily based on:
26 * adiantum length-preserving encryption mode
27 *
28 * Copyright 2018 Google LLC
29 */
30
31#include <crypto/authenc.h>
32#include <crypto/internal/aead.h>
33#include <crypto/internal/cipher.h>
34#include <crypto/internal/hash.h>
35#include <crypto/internal/skcipher.h>
36#include <crypto/scatterwalk.h>
37#include <linux/module.h>
38
39#include "internal.h"
40
41struct essiv_instance_ctx {
42 union {
43 struct crypto_skcipher_spawn skcipher_spawn;
44 struct crypto_aead_spawn aead_spawn;
45 } u;
46 char essiv_cipher_name[CRYPTO_MAX_ALG_NAME];
47 char shash_driver_name[CRYPTO_MAX_ALG_NAME];
48};
49
50struct essiv_tfm_ctx {
51 union {
52 struct crypto_skcipher *skcipher;
53 struct crypto_aead *aead;
54 } u;
55 struct crypto_cipher *essiv_cipher;
56 struct crypto_shash *hash;
57 int ivoffset;
58};
59
60struct essiv_aead_request_ctx {
61 struct scatterlist sg[4];
62 u8 *assoc;
63 struct aead_request aead_req;
64};
65
66static int essiv_skcipher_setkey(struct crypto_skcipher *tfm,
67 const u8 *key, unsigned int keylen)
68{
69 struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
70 u8 salt[HASH_MAX_DIGESTSIZE];
71 int err;
72
73 crypto_skcipher_clear_flags(tfm: tctx->u.skcipher, CRYPTO_TFM_REQ_MASK);
74 crypto_skcipher_set_flags(tfm: tctx->u.skcipher,
75 flags: crypto_skcipher_get_flags(tfm) &
76 CRYPTO_TFM_REQ_MASK);
77 err = crypto_skcipher_setkey(tfm: tctx->u.skcipher, key, keylen);
78 if (err)
79 return err;
80
81 err = crypto_shash_tfm_digest(tfm: tctx->hash, data: key, len: keylen, out: salt);
82 if (err)
83 return err;
84
85 crypto_cipher_clear_flags(tfm: tctx->essiv_cipher, CRYPTO_TFM_REQ_MASK);
86 crypto_cipher_set_flags(tfm: tctx->essiv_cipher,
87 flags: crypto_skcipher_get_flags(tfm) &
88 CRYPTO_TFM_REQ_MASK);
89 return crypto_cipher_setkey(tfm: tctx->essiv_cipher, key: salt,
90 keylen: crypto_shash_digestsize(tfm: tctx->hash));
91}
92
93static int essiv_aead_setkey(struct crypto_aead *tfm, const u8 *key,
94 unsigned int keylen)
95{
96 struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
97 SHASH_DESC_ON_STACK(desc, tctx->hash);
98 struct crypto_authenc_keys keys;
99 u8 salt[HASH_MAX_DIGESTSIZE];
100 int err;
101
102 crypto_aead_clear_flags(tfm: tctx->u.aead, CRYPTO_TFM_REQ_MASK);
103 crypto_aead_set_flags(tfm: tctx->u.aead, flags: crypto_aead_get_flags(tfm) &
104 CRYPTO_TFM_REQ_MASK);
105 err = crypto_aead_setkey(tfm: tctx->u.aead, key, keylen);
106 if (err)
107 return err;
108
109 if (crypto_authenc_extractkeys(keys: &keys, key, keylen) != 0)
110 return -EINVAL;
111
112 desc->tfm = tctx->hash;
113 err = crypto_shash_init(desc) ?:
114 crypto_shash_update(desc, data: keys.enckey, len: keys.enckeylen) ?:
115 crypto_shash_finup(desc, data: keys.authkey, len: keys.authkeylen, out: salt);
116 if (err)
117 return err;
118
119 crypto_cipher_clear_flags(tfm: tctx->essiv_cipher, CRYPTO_TFM_REQ_MASK);
120 crypto_cipher_set_flags(tfm: tctx->essiv_cipher, flags: crypto_aead_get_flags(tfm) &
121 CRYPTO_TFM_REQ_MASK);
122 return crypto_cipher_setkey(tfm: tctx->essiv_cipher, key: salt,
123 keylen: crypto_shash_digestsize(tfm: tctx->hash));
124}
125
126static int essiv_aead_setauthsize(struct crypto_aead *tfm,
127 unsigned int authsize)
128{
129 struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
130
131 return crypto_aead_setauthsize(tfm: tctx->u.aead, authsize);
132}
133
134static void essiv_skcipher_done(void *data, int err)
135{
136 struct skcipher_request *req = data;
137
138 skcipher_request_complete(req, err);
139}
140
141static int essiv_skcipher_crypt(struct skcipher_request *req, bool enc)
142{
143 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
144 const struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
145 struct skcipher_request *subreq = skcipher_request_ctx(req);
146
147 crypto_cipher_encrypt_one(tfm: tctx->essiv_cipher, dst: req->iv, src: req->iv);
148
149 skcipher_request_set_tfm(req: subreq, tfm: tctx->u.skcipher);
150 skcipher_request_set_crypt(req: subreq, src: req->src, dst: req->dst, cryptlen: req->cryptlen,
151 iv: req->iv);
152 skcipher_request_set_callback(req: subreq, flags: skcipher_request_flags(req),
153 compl: essiv_skcipher_done, data: req);
154
155 return enc ? crypto_skcipher_encrypt(req: subreq) :
156 crypto_skcipher_decrypt(req: subreq);
157}
158
159static int essiv_skcipher_encrypt(struct skcipher_request *req)
160{
161 return essiv_skcipher_crypt(req, enc: true);
162}
163
164static int essiv_skcipher_decrypt(struct skcipher_request *req)
165{
166 return essiv_skcipher_crypt(req, enc: false);
167}
168
169static void essiv_aead_done(void *data, int err)
170{
171 struct aead_request *req = data;
172 struct essiv_aead_request_ctx *rctx = aead_request_ctx(req);
173
174 if (err == -EINPROGRESS)
175 goto out;
176
177 kfree(objp: rctx->assoc);
178
179out:
180 aead_request_complete(req, err);
181}
182
183static int essiv_aead_crypt(struct aead_request *req, bool enc)
184{
185 struct crypto_aead *tfm = crypto_aead_reqtfm(req);
186 const struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
187 struct essiv_aead_request_ctx *rctx = aead_request_ctx(req);
188 struct aead_request *subreq = &rctx->aead_req;
189 struct scatterlist *src = req->src;
190 int err;
191
192 crypto_cipher_encrypt_one(tfm: tctx->essiv_cipher, dst: req->iv, src: req->iv);
193
194 /*
195 * dm-crypt embeds the sector number and the IV in the AAD region, so
196 * we have to copy the converted IV into the right scatterlist before
197 * we pass it on.
198 */
199 rctx->assoc = NULL;
200 if (req->src == req->dst || !enc) {
201 scatterwalk_map_and_copy(buf: req->iv, sg: req->dst,
202 start: req->assoclen - crypto_aead_ivsize(tfm),
203 nbytes: crypto_aead_ivsize(tfm), out: 1);
204 } else {
205 u8 *iv = (u8 *)aead_request_ctx(req) + tctx->ivoffset;
206 int ivsize = crypto_aead_ivsize(tfm);
207 int ssize = req->assoclen - ivsize;
208 struct scatterlist *sg;
209 int nents;
210
211 if (ssize < 0)
212 return -EINVAL;
213
214 nents = sg_nents_for_len(sg: req->src, len: ssize);
215 if (nents < 0)
216 return -EINVAL;
217
218 memcpy(iv, req->iv, ivsize);
219 sg_init_table(rctx->sg, 4);
220
221 if (unlikely(nents > 1)) {
222 /*
223 * This is a case that rarely occurs in practice, but
224 * for correctness, we have to deal with it nonetheless.
225 */
226 rctx->assoc = kmalloc(size: ssize, GFP_ATOMIC);
227 if (!rctx->assoc)
228 return -ENOMEM;
229
230 scatterwalk_map_and_copy(buf: rctx->assoc, sg: req->src, start: 0,
231 nbytes: ssize, out: 0);
232 sg_set_buf(sg: rctx->sg, buf: rctx->assoc, buflen: ssize);
233 } else {
234 sg_set_page(sg: rctx->sg, page: sg_page(sg: req->src), len: ssize,
235 offset: req->src->offset);
236 }
237
238 sg_set_buf(sg: rctx->sg + 1, buf: iv, buflen: ivsize);
239 sg = scatterwalk_ffwd(dst: rctx->sg + 2, src: req->src, len: req->assoclen);
240 if (sg != rctx->sg + 2)
241 sg_chain(prv: rctx->sg, prv_nents: 3, sgl: sg);
242
243 src = rctx->sg;
244 }
245
246 aead_request_set_tfm(req: subreq, tfm: tctx->u.aead);
247 aead_request_set_ad(req: subreq, assoclen: req->assoclen);
248 aead_request_set_callback(req: subreq, flags: aead_request_flags(req),
249 compl: essiv_aead_done, data: req);
250 aead_request_set_crypt(req: subreq, src, dst: req->dst, cryptlen: req->cryptlen, iv: req->iv);
251
252 err = enc ? crypto_aead_encrypt(req: subreq) :
253 crypto_aead_decrypt(req: subreq);
254
255 if (rctx->assoc && err != -EINPROGRESS && err != -EBUSY)
256 kfree(objp: rctx->assoc);
257 return err;
258}
259
260static int essiv_aead_encrypt(struct aead_request *req)
261{
262 return essiv_aead_crypt(req, enc: true);
263}
264
265static int essiv_aead_decrypt(struct aead_request *req)
266{
267 return essiv_aead_crypt(req, enc: false);
268}
269
270static int essiv_init_tfm(struct essiv_instance_ctx *ictx,
271 struct essiv_tfm_ctx *tctx)
272{
273 struct crypto_cipher *essiv_cipher;
274 struct crypto_shash *hash;
275 int err;
276
277 essiv_cipher = crypto_alloc_cipher(alg_name: ictx->essiv_cipher_name, type: 0, mask: 0);
278 if (IS_ERR(ptr: essiv_cipher))
279 return PTR_ERR(ptr: essiv_cipher);
280
281 hash = crypto_alloc_shash(alg_name: ictx->shash_driver_name, type: 0, mask: 0);
282 if (IS_ERR(ptr: hash)) {
283 err = PTR_ERR(ptr: hash);
284 goto err_free_essiv_cipher;
285 }
286
287 tctx->essiv_cipher = essiv_cipher;
288 tctx->hash = hash;
289
290 return 0;
291
292err_free_essiv_cipher:
293 crypto_free_cipher(tfm: essiv_cipher);
294 return err;
295}
296
297static int essiv_skcipher_init_tfm(struct crypto_skcipher *tfm)
298{
299 struct skcipher_instance *inst = skcipher_alg_instance(skcipher: tfm);
300 struct essiv_instance_ctx *ictx = skcipher_instance_ctx(inst);
301 struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
302 struct crypto_skcipher *skcipher;
303 int err;
304
305 skcipher = crypto_spawn_skcipher(spawn: &ictx->u.skcipher_spawn);
306 if (IS_ERR(ptr: skcipher))
307 return PTR_ERR(ptr: skcipher);
308
309 crypto_skcipher_set_reqsize(skcipher: tfm, reqsize: sizeof(struct skcipher_request) +
310 crypto_skcipher_reqsize(tfm: skcipher));
311
312 err = essiv_init_tfm(ictx, tctx);
313 if (err) {
314 crypto_free_skcipher(tfm: skcipher);
315 return err;
316 }
317
318 tctx->u.skcipher = skcipher;
319 return 0;
320}
321
322static int essiv_aead_init_tfm(struct crypto_aead *tfm)
323{
324 struct aead_instance *inst = aead_alg_instance(aead: tfm);
325 struct essiv_instance_ctx *ictx = aead_instance_ctx(inst);
326 struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
327 struct crypto_aead *aead;
328 unsigned int subreq_size;
329 int err;
330
331 BUILD_BUG_ON(offsetofend(struct essiv_aead_request_ctx, aead_req) !=
332 sizeof(struct essiv_aead_request_ctx));
333
334 aead = crypto_spawn_aead(spawn: &ictx->u.aead_spawn);
335 if (IS_ERR(ptr: aead))
336 return PTR_ERR(ptr: aead);
337
338 subreq_size = sizeof_field(struct essiv_aead_request_ctx, aead_req) +
339 crypto_aead_reqsize(tfm: aead);
340
341 tctx->ivoffset = offsetof(struct essiv_aead_request_ctx, aead_req) +
342 subreq_size;
343 crypto_aead_set_reqsize(aead: tfm, reqsize: tctx->ivoffset + crypto_aead_ivsize(tfm: aead));
344
345 err = essiv_init_tfm(ictx, tctx);
346 if (err) {
347 crypto_free_aead(tfm: aead);
348 return err;
349 }
350
351 tctx->u.aead = aead;
352 return 0;
353}
354
355static void essiv_skcipher_exit_tfm(struct crypto_skcipher *tfm)
356{
357 struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
358
359 crypto_free_skcipher(tfm: tctx->u.skcipher);
360 crypto_free_cipher(tfm: tctx->essiv_cipher);
361 crypto_free_shash(tfm: tctx->hash);
362}
363
364static void essiv_aead_exit_tfm(struct crypto_aead *tfm)
365{
366 struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
367
368 crypto_free_aead(tfm: tctx->u.aead);
369 crypto_free_cipher(tfm: tctx->essiv_cipher);
370 crypto_free_shash(tfm: tctx->hash);
371}
372
373static void essiv_skcipher_free_instance(struct skcipher_instance *inst)
374{
375 struct essiv_instance_ctx *ictx = skcipher_instance_ctx(inst);
376
377 crypto_drop_skcipher(spawn: &ictx->u.skcipher_spawn);
378 kfree(objp: inst);
379}
380
381static void essiv_aead_free_instance(struct aead_instance *inst)
382{
383 struct essiv_instance_ctx *ictx = aead_instance_ctx(inst);
384
385 crypto_drop_aead(spawn: &ictx->u.aead_spawn);
386 kfree(objp: inst);
387}
388
389static bool parse_cipher_name(char *essiv_cipher_name, const char *cra_name)
390{
391 const char *p, *q;
392 int len;
393
394 /* find the last opening parens */
395 p = strrchr(cra_name, '(');
396 if (!p++)
397 return false;
398
399 /* find the first closing parens in the tail of the string */
400 q = strchr(p, ')');
401 if (!q)
402 return false;
403
404 len = q - p;
405 if (len >= CRYPTO_MAX_ALG_NAME)
406 return false;
407
408 memcpy(essiv_cipher_name, p, len);
409 essiv_cipher_name[len] = '\0';
410 return true;
411}
412
413static bool essiv_supported_algorithms(const char *essiv_cipher_name,
414 struct shash_alg *hash_alg,
415 int ivsize)
416{
417 struct crypto_alg *alg;
418 bool ret = false;
419
420 alg = crypto_alg_mod_lookup(name: essiv_cipher_name,
421 CRYPTO_ALG_TYPE_CIPHER,
422 CRYPTO_ALG_TYPE_MASK);
423 if (IS_ERR(ptr: alg))
424 return false;
425
426 if (hash_alg->digestsize < alg->cra_cipher.cia_min_keysize ||
427 hash_alg->digestsize > alg->cra_cipher.cia_max_keysize)
428 goto out;
429
430 if (ivsize != alg->cra_blocksize)
431 goto out;
432
433 if (crypto_shash_alg_needs_key(alg: hash_alg))
434 goto out;
435
436 ret = true;
437
438out:
439 crypto_mod_put(alg);
440 return ret;
441}
442
443static int essiv_create(struct crypto_template *tmpl, struct rtattr **tb)
444{
445 struct skcipher_alg_common *skcipher_alg = NULL;
446 struct crypto_attr_type *algt;
447 const char *inner_cipher_name;
448 const char *shash_name;
449 struct skcipher_instance *skcipher_inst = NULL;
450 struct aead_instance *aead_inst = NULL;
451 struct crypto_instance *inst;
452 struct crypto_alg *base, *block_base;
453 struct essiv_instance_ctx *ictx;
454 struct aead_alg *aead_alg = NULL;
455 struct crypto_alg *_hash_alg;
456 struct shash_alg *hash_alg;
457 int ivsize;
458 u32 type;
459 u32 mask;
460 int err;
461
462 algt = crypto_get_attr_type(tb);
463 if (IS_ERR(ptr: algt))
464 return PTR_ERR(ptr: algt);
465
466 inner_cipher_name = crypto_attr_alg_name(rta: tb[1]);
467 if (IS_ERR(ptr: inner_cipher_name))
468 return PTR_ERR(ptr: inner_cipher_name);
469
470 shash_name = crypto_attr_alg_name(rta: tb[2]);
471 if (IS_ERR(ptr: shash_name))
472 return PTR_ERR(ptr: shash_name);
473
474 type = algt->type & algt->mask;
475 mask = crypto_algt_inherited_mask(algt);
476
477 switch (type) {
478 case CRYPTO_ALG_TYPE_LSKCIPHER:
479 skcipher_inst = kzalloc(size: sizeof(*skcipher_inst) +
480 sizeof(*ictx), GFP_KERNEL);
481 if (!skcipher_inst)
482 return -ENOMEM;
483 inst = skcipher_crypto_instance(inst: skcipher_inst);
484 base = &skcipher_inst->alg.base;
485 ictx = crypto_instance_ctx(inst);
486
487 /* Symmetric cipher, e.g., "cbc(aes)" */
488 err = crypto_grab_skcipher(spawn: &ictx->u.skcipher_spawn, inst,
489 name: inner_cipher_name, type: 0, mask);
490 if (err)
491 goto out_free_inst;
492 skcipher_alg = crypto_spawn_skcipher_alg_common(
493 spawn: &ictx->u.skcipher_spawn);
494 block_base = &skcipher_alg->base;
495 ivsize = skcipher_alg->ivsize;
496 break;
497
498 case CRYPTO_ALG_TYPE_AEAD:
499 aead_inst = kzalloc(size: sizeof(*aead_inst) +
500 sizeof(*ictx), GFP_KERNEL);
501 if (!aead_inst)
502 return -ENOMEM;
503 inst = aead_crypto_instance(inst: aead_inst);
504 base = &aead_inst->alg.base;
505 ictx = crypto_instance_ctx(inst);
506
507 /* AEAD cipher, e.g., "authenc(hmac(sha256),cbc(aes))" */
508 err = crypto_grab_aead(spawn: &ictx->u.aead_spawn, inst,
509 name: inner_cipher_name, type: 0, mask);
510 if (err)
511 goto out_free_inst;
512 aead_alg = crypto_spawn_aead_alg(spawn: &ictx->u.aead_spawn);
513 block_base = &aead_alg->base;
514 if (!strstarts(str: block_base->cra_name, prefix: "authenc(")) {
515 pr_warn("Only authenc() type AEADs are supported by ESSIV\n");
516 err = -EINVAL;
517 goto out_drop_skcipher;
518 }
519 ivsize = aead_alg->ivsize;
520 break;
521
522 default:
523 return -EINVAL;
524 }
525
526 if (!parse_cipher_name(essiv_cipher_name: ictx->essiv_cipher_name, cra_name: block_base->cra_name)) {
527 pr_warn("Failed to parse ESSIV cipher name from skcipher cra_name\n");
528 err = -EINVAL;
529 goto out_drop_skcipher;
530 }
531
532 /* Synchronous hash, e.g., "sha256" */
533 _hash_alg = crypto_alg_mod_lookup(name: shash_name,
534 CRYPTO_ALG_TYPE_SHASH,
535 CRYPTO_ALG_TYPE_MASK | mask);
536 if (IS_ERR(ptr: _hash_alg)) {
537 err = PTR_ERR(ptr: _hash_alg);
538 goto out_drop_skcipher;
539 }
540 hash_alg = __crypto_shash_alg(alg: _hash_alg);
541
542 /* Check the set of algorithms */
543 if (!essiv_supported_algorithms(essiv_cipher_name: ictx->essiv_cipher_name, hash_alg,
544 ivsize)) {
545 pr_warn("Unsupported essiv instantiation: essiv(%s,%s)\n",
546 block_base->cra_name, hash_alg->base.cra_name);
547 err = -EINVAL;
548 goto out_free_hash;
549 }
550
551 /* record the driver name so we can instantiate this exact algo later */
552 strscpy(p: ictx->shash_driver_name, q: hash_alg->base.cra_driver_name,
553 CRYPTO_MAX_ALG_NAME);
554
555 /* Instance fields */
556
557 err = -ENAMETOOLONG;
558 if (snprintf(buf: base->cra_name, CRYPTO_MAX_ALG_NAME,
559 fmt: "essiv(%s,%s)", block_base->cra_name,
560 hash_alg->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
561 goto out_free_hash;
562 if (snprintf(buf: base->cra_driver_name, CRYPTO_MAX_ALG_NAME,
563 fmt: "essiv(%s,%s)", block_base->cra_driver_name,
564 hash_alg->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
565 goto out_free_hash;
566
567 /*
568 * hash_alg wasn't gotten via crypto_grab*(), so we need to inherit its
569 * flags manually.
570 */
571 base->cra_flags |= (hash_alg->base.cra_flags &
572 CRYPTO_ALG_INHERITED_FLAGS);
573 base->cra_blocksize = block_base->cra_blocksize;
574 base->cra_ctxsize = sizeof(struct essiv_tfm_ctx);
575 base->cra_alignmask = block_base->cra_alignmask;
576 base->cra_priority = block_base->cra_priority;
577
578 if (type == CRYPTO_ALG_TYPE_LSKCIPHER) {
579 skcipher_inst->alg.setkey = essiv_skcipher_setkey;
580 skcipher_inst->alg.encrypt = essiv_skcipher_encrypt;
581 skcipher_inst->alg.decrypt = essiv_skcipher_decrypt;
582 skcipher_inst->alg.init = essiv_skcipher_init_tfm;
583 skcipher_inst->alg.exit = essiv_skcipher_exit_tfm;
584
585 skcipher_inst->alg.min_keysize = skcipher_alg->min_keysize;
586 skcipher_inst->alg.max_keysize = skcipher_alg->max_keysize;
587 skcipher_inst->alg.ivsize = ivsize;
588 skcipher_inst->alg.chunksize = skcipher_alg->chunksize;
589
590 skcipher_inst->free = essiv_skcipher_free_instance;
591
592 err = skcipher_register_instance(tmpl, inst: skcipher_inst);
593 } else {
594 aead_inst->alg.setkey = essiv_aead_setkey;
595 aead_inst->alg.setauthsize = essiv_aead_setauthsize;
596 aead_inst->alg.encrypt = essiv_aead_encrypt;
597 aead_inst->alg.decrypt = essiv_aead_decrypt;
598 aead_inst->alg.init = essiv_aead_init_tfm;
599 aead_inst->alg.exit = essiv_aead_exit_tfm;
600
601 aead_inst->alg.ivsize = ivsize;
602 aead_inst->alg.maxauthsize = crypto_aead_alg_maxauthsize(alg: aead_alg);
603 aead_inst->alg.chunksize = crypto_aead_alg_chunksize(alg: aead_alg);
604
605 aead_inst->free = essiv_aead_free_instance;
606
607 err = aead_register_instance(tmpl, inst: aead_inst);
608 }
609
610 if (err)
611 goto out_free_hash;
612
613 crypto_mod_put(alg: _hash_alg);
614 return 0;
615
616out_free_hash:
617 crypto_mod_put(alg: _hash_alg);
618out_drop_skcipher:
619 if (type == CRYPTO_ALG_TYPE_LSKCIPHER)
620 crypto_drop_skcipher(spawn: &ictx->u.skcipher_spawn);
621 else
622 crypto_drop_aead(spawn: &ictx->u.aead_spawn);
623out_free_inst:
624 kfree(objp: skcipher_inst);
625 kfree(objp: aead_inst);
626 return err;
627}
628
629/* essiv(cipher_name, shash_name) */
630static struct crypto_template essiv_tmpl = {
631 .name = "essiv",
632 .create = essiv_create,
633 .module = THIS_MODULE,
634};
635
636static int __init essiv_module_init(void)
637{
638 return crypto_register_template(tmpl: &essiv_tmpl);
639}
640
641static void __exit essiv_module_exit(void)
642{
643 crypto_unregister_template(tmpl: &essiv_tmpl);
644}
645
646subsys_initcall(essiv_module_init);
647module_exit(essiv_module_exit);
648
649MODULE_DESCRIPTION("ESSIV skcipher/aead wrapper for block encryption");
650MODULE_LICENSE("GPL v2");
651MODULE_ALIAS_CRYPTO("essiv");
652MODULE_IMPORT_NS(CRYPTO_INTERNAL);
653

source code of linux/crypto/essiv.c