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