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