xref: /linux/crypto/ahash.c (revision b7e1e969c887c897947fdc3754fe9b0c24acb155)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Asynchronous Cryptographic Hash operations.
4  *
5  * This is the implementation of the ahash (asynchronous hash) API.  It differs
6  * from shash (synchronous hash) in that ahash supports asynchronous operations,
7  * and it hashes data from scatterlists instead of virtually addressed buffers.
8  *
9  * The ahash API provides access to both ahash and shash algorithms.  The shash
10  * API only provides access to shash algorithms.
11  *
12  * Copyright (c) 2008 Loc Ho <lho@amcc.com>
13  */
14 
15 #include <crypto/scatterwalk.h>
16 #include <linux/cryptouser.h>
17 #include <linux/err.h>
18 #include <linux/kernel.h>
19 #include <linux/module.h>
20 #include <linux/sched.h>
21 #include <linux/slab.h>
22 #include <linux/seq_file.h>
23 #include <linux/string.h>
24 #include <net/netlink.h>
25 
26 #include "hash.h"
27 
28 #define CRYPTO_ALG_TYPE_AHASH_MASK	0x0000000e
29 
30 static inline struct crypto_istat_hash *ahash_get_stat(struct ahash_alg *alg)
31 {
32 	return hash_get_stat(&alg->halg);
33 }
34 
35 static inline int crypto_ahash_errstat(struct ahash_alg *alg, int err)
36 {
37 	if (!IS_ENABLED(CONFIG_CRYPTO_STATS))
38 		return err;
39 
40 	if (err && err != -EINPROGRESS && err != -EBUSY)
41 		atomic64_inc(&ahash_get_stat(alg)->err_cnt);
42 
43 	return err;
44 }
45 
46 /*
47  * For an ahash tfm that is using an shash algorithm (instead of an ahash
48  * algorithm), this returns the underlying shash tfm.
49  */
50 static inline struct crypto_shash *ahash_to_shash(struct crypto_ahash *tfm)
51 {
52 	return *(struct crypto_shash **)crypto_ahash_ctx(tfm);
53 }
54 
55 static inline struct shash_desc *prepare_shash_desc(struct ahash_request *req,
56 						    struct crypto_ahash *tfm)
57 {
58 	struct shash_desc *desc = ahash_request_ctx(req);
59 
60 	desc->tfm = ahash_to_shash(tfm);
61 	return desc;
62 }
63 
64 int shash_ahash_update(struct ahash_request *req, struct shash_desc *desc)
65 {
66 	struct crypto_hash_walk walk;
67 	int nbytes;
68 
69 	for (nbytes = crypto_hash_walk_first(req, &walk); nbytes > 0;
70 	     nbytes = crypto_hash_walk_done(&walk, nbytes))
71 		nbytes = crypto_shash_update(desc, walk.data, nbytes);
72 
73 	return nbytes;
74 }
75 EXPORT_SYMBOL_GPL(shash_ahash_update);
76 
77 int shash_ahash_finup(struct ahash_request *req, struct shash_desc *desc)
78 {
79 	struct crypto_hash_walk walk;
80 	int nbytes;
81 
82 	nbytes = crypto_hash_walk_first(req, &walk);
83 	if (!nbytes)
84 		return crypto_shash_final(desc, req->result);
85 
86 	do {
87 		nbytes = crypto_hash_walk_last(&walk) ?
88 			 crypto_shash_finup(desc, walk.data, nbytes,
89 					    req->result) :
90 			 crypto_shash_update(desc, walk.data, nbytes);
91 		nbytes = crypto_hash_walk_done(&walk, nbytes);
92 	} while (nbytes > 0);
93 
94 	return nbytes;
95 }
96 EXPORT_SYMBOL_GPL(shash_ahash_finup);
97 
98 int shash_ahash_digest(struct ahash_request *req, struct shash_desc *desc)
99 {
100 	unsigned int nbytes = req->nbytes;
101 	struct scatterlist *sg;
102 	unsigned int offset;
103 	int err;
104 
105 	if (nbytes &&
106 	    (sg = req->src, offset = sg->offset,
107 	     nbytes <= min(sg->length, ((unsigned int)(PAGE_SIZE)) - offset))) {
108 		void *data;
109 
110 		data = kmap_local_page(sg_page(sg));
111 		err = crypto_shash_digest(desc, data + offset, nbytes,
112 					  req->result);
113 		kunmap_local(data);
114 	} else
115 		err = crypto_shash_init(desc) ?:
116 		      shash_ahash_finup(req, desc);
117 
118 	return err;
119 }
120 EXPORT_SYMBOL_GPL(shash_ahash_digest);
121 
122 static void crypto_exit_ahash_using_shash(struct crypto_tfm *tfm)
123 {
124 	struct crypto_shash **ctx = crypto_tfm_ctx(tfm);
125 
126 	crypto_free_shash(*ctx);
127 }
128 
129 static int crypto_init_ahash_using_shash(struct crypto_tfm *tfm)
130 {
131 	struct crypto_alg *calg = tfm->__crt_alg;
132 	struct crypto_ahash *crt = __crypto_ahash_cast(tfm);
133 	struct crypto_shash **ctx = crypto_tfm_ctx(tfm);
134 	struct crypto_shash *shash;
135 
136 	if (!crypto_mod_get(calg))
137 		return -EAGAIN;
138 
139 	shash = crypto_create_tfm(calg, &crypto_shash_type);
140 	if (IS_ERR(shash)) {
141 		crypto_mod_put(calg);
142 		return PTR_ERR(shash);
143 	}
144 
145 	crt->using_shash = true;
146 	*ctx = shash;
147 	tfm->exit = crypto_exit_ahash_using_shash;
148 
149 	crypto_ahash_set_flags(crt, crypto_shash_get_flags(shash) &
150 				    CRYPTO_TFM_NEED_KEY);
151 	crt->reqsize = sizeof(struct shash_desc) + crypto_shash_descsize(shash);
152 
153 	return 0;
154 }
155 
156 static int hash_walk_next(struct crypto_hash_walk *walk)
157 {
158 	unsigned int offset = walk->offset;
159 	unsigned int nbytes = min(walk->entrylen,
160 				  ((unsigned int)(PAGE_SIZE)) - offset);
161 
162 	walk->data = kmap_local_page(walk->pg);
163 	walk->data += offset;
164 	walk->entrylen -= nbytes;
165 	return nbytes;
166 }
167 
168 static int hash_walk_new_entry(struct crypto_hash_walk *walk)
169 {
170 	struct scatterlist *sg;
171 
172 	sg = walk->sg;
173 	walk->offset = sg->offset;
174 	walk->pg = sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
175 	walk->offset = offset_in_page(walk->offset);
176 	walk->entrylen = sg->length;
177 
178 	if (walk->entrylen > walk->total)
179 		walk->entrylen = walk->total;
180 	walk->total -= walk->entrylen;
181 
182 	return hash_walk_next(walk);
183 }
184 
185 int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
186 {
187 	walk->data -= walk->offset;
188 
189 	kunmap_local(walk->data);
190 	crypto_yield(walk->flags);
191 
192 	if (err)
193 		return err;
194 
195 	if (walk->entrylen) {
196 		walk->offset = 0;
197 		walk->pg++;
198 		return hash_walk_next(walk);
199 	}
200 
201 	if (!walk->total)
202 		return 0;
203 
204 	walk->sg = sg_next(walk->sg);
205 
206 	return hash_walk_new_entry(walk);
207 }
208 EXPORT_SYMBOL_GPL(crypto_hash_walk_done);
209 
210 int crypto_hash_walk_first(struct ahash_request *req,
211 			   struct crypto_hash_walk *walk)
212 {
213 	walk->total = req->nbytes;
214 
215 	if (!walk->total) {
216 		walk->entrylen = 0;
217 		return 0;
218 	}
219 
220 	walk->sg = req->src;
221 	walk->flags = req->base.flags;
222 
223 	return hash_walk_new_entry(walk);
224 }
225 EXPORT_SYMBOL_GPL(crypto_hash_walk_first);
226 
227 static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
228 			  unsigned int keylen)
229 {
230 	return -ENOSYS;
231 }
232 
233 static void ahash_set_needkey(struct crypto_ahash *tfm, struct ahash_alg *alg)
234 {
235 	if (alg->setkey != ahash_nosetkey &&
236 	    !(alg->halg.base.cra_flags & CRYPTO_ALG_OPTIONAL_KEY))
237 		crypto_ahash_set_flags(tfm, CRYPTO_TFM_NEED_KEY);
238 }
239 
240 int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
241 			unsigned int keylen)
242 {
243 	if (likely(tfm->using_shash)) {
244 		struct crypto_shash *shash = ahash_to_shash(tfm);
245 		int err;
246 
247 		err = crypto_shash_setkey(shash, key, keylen);
248 		if (unlikely(err)) {
249 			crypto_ahash_set_flags(tfm,
250 					       crypto_shash_get_flags(shash) &
251 					       CRYPTO_TFM_NEED_KEY);
252 			return err;
253 		}
254 	} else {
255 		struct ahash_alg *alg = crypto_ahash_alg(tfm);
256 		int err;
257 
258 		err = alg->setkey(tfm, key, keylen);
259 		if (unlikely(err)) {
260 			ahash_set_needkey(tfm, alg);
261 			return err;
262 		}
263 	}
264 	crypto_ahash_clear_flags(tfm, CRYPTO_TFM_NEED_KEY);
265 	return 0;
266 }
267 EXPORT_SYMBOL_GPL(crypto_ahash_setkey);
268 
269 int crypto_ahash_init(struct ahash_request *req)
270 {
271 	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
272 
273 	if (likely(tfm->using_shash))
274 		return crypto_shash_init(prepare_shash_desc(req, tfm));
275 	if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
276 		return -ENOKEY;
277 	return crypto_ahash_alg(tfm)->init(req);
278 }
279 EXPORT_SYMBOL_GPL(crypto_ahash_init);
280 
281 static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt,
282 			  bool has_state)
283 {
284 	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
285 	unsigned int ds = crypto_ahash_digestsize(tfm);
286 	struct ahash_request *subreq;
287 	unsigned int subreq_size;
288 	unsigned int reqsize;
289 	u8 *result;
290 	gfp_t gfp;
291 	u32 flags;
292 
293 	subreq_size = sizeof(*subreq);
294 	reqsize = crypto_ahash_reqsize(tfm);
295 	reqsize = ALIGN(reqsize, crypto_tfm_ctx_alignment());
296 	subreq_size += reqsize;
297 	subreq_size += ds;
298 
299 	flags = ahash_request_flags(req);
300 	gfp = (flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?  GFP_KERNEL : GFP_ATOMIC;
301 	subreq = kmalloc(subreq_size, gfp);
302 	if (!subreq)
303 		return -ENOMEM;
304 
305 	ahash_request_set_tfm(subreq, tfm);
306 	ahash_request_set_callback(subreq, flags, cplt, req);
307 
308 	result = (u8 *)(subreq + 1) + reqsize;
309 
310 	ahash_request_set_crypt(subreq, req->src, result, req->nbytes);
311 
312 	if (has_state) {
313 		void *state;
314 
315 		state = kmalloc(crypto_ahash_statesize(tfm), gfp);
316 		if (!state) {
317 			kfree(subreq);
318 			return -ENOMEM;
319 		}
320 
321 		crypto_ahash_export(req, state);
322 		crypto_ahash_import(subreq, state);
323 		kfree_sensitive(state);
324 	}
325 
326 	req->priv = subreq;
327 
328 	return 0;
329 }
330 
331 static void ahash_restore_req(struct ahash_request *req, int err)
332 {
333 	struct ahash_request *subreq = req->priv;
334 
335 	if (!err)
336 		memcpy(req->result, subreq->result,
337 		       crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
338 
339 	req->priv = NULL;
340 
341 	kfree_sensitive(subreq);
342 }
343 
344 int crypto_ahash_update(struct ahash_request *req)
345 {
346 	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
347 	struct ahash_alg *alg;
348 
349 	if (likely(tfm->using_shash))
350 		return shash_ahash_update(req, ahash_request_ctx(req));
351 
352 	alg = crypto_ahash_alg(tfm);
353 	if (IS_ENABLED(CONFIG_CRYPTO_STATS))
354 		atomic64_add(req->nbytes, &ahash_get_stat(alg)->hash_tlen);
355 	return crypto_ahash_errstat(alg, alg->update(req));
356 }
357 EXPORT_SYMBOL_GPL(crypto_ahash_update);
358 
359 int crypto_ahash_final(struct ahash_request *req)
360 {
361 	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
362 	struct ahash_alg *alg;
363 
364 	if (likely(tfm->using_shash))
365 		return crypto_shash_final(ahash_request_ctx(req), req->result);
366 
367 	alg = crypto_ahash_alg(tfm);
368 	if (IS_ENABLED(CONFIG_CRYPTO_STATS))
369 		atomic64_inc(&ahash_get_stat(alg)->hash_cnt);
370 	return crypto_ahash_errstat(alg, alg->final(req));
371 }
372 EXPORT_SYMBOL_GPL(crypto_ahash_final);
373 
374 int crypto_ahash_finup(struct ahash_request *req)
375 {
376 	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
377 	struct ahash_alg *alg;
378 
379 	if (likely(tfm->using_shash))
380 		return shash_ahash_finup(req, ahash_request_ctx(req));
381 
382 	alg = crypto_ahash_alg(tfm);
383 	if (IS_ENABLED(CONFIG_CRYPTO_STATS)) {
384 		struct crypto_istat_hash *istat = ahash_get_stat(alg);
385 
386 		atomic64_inc(&istat->hash_cnt);
387 		atomic64_add(req->nbytes, &istat->hash_tlen);
388 	}
389 	return crypto_ahash_errstat(alg, alg->finup(req));
390 }
391 EXPORT_SYMBOL_GPL(crypto_ahash_finup);
392 
393 int crypto_ahash_digest(struct ahash_request *req)
394 {
395 	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
396 	struct ahash_alg *alg;
397 	int err;
398 
399 	if (likely(tfm->using_shash))
400 		return shash_ahash_digest(req, prepare_shash_desc(req, tfm));
401 
402 	alg = crypto_ahash_alg(tfm);
403 	if (IS_ENABLED(CONFIG_CRYPTO_STATS)) {
404 		struct crypto_istat_hash *istat = ahash_get_stat(alg);
405 
406 		atomic64_inc(&istat->hash_cnt);
407 		atomic64_add(req->nbytes, &istat->hash_tlen);
408 	}
409 
410 	if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
411 		err = -ENOKEY;
412 	else
413 		err = alg->digest(req);
414 
415 	return crypto_ahash_errstat(alg, err);
416 }
417 EXPORT_SYMBOL_GPL(crypto_ahash_digest);
418 
419 static void ahash_def_finup_done2(void *data, int err)
420 {
421 	struct ahash_request *areq = data;
422 
423 	if (err == -EINPROGRESS)
424 		return;
425 
426 	ahash_restore_req(areq, err);
427 
428 	ahash_request_complete(areq, err);
429 }
430 
431 static int ahash_def_finup_finish1(struct ahash_request *req, int err)
432 {
433 	struct ahash_request *subreq = req->priv;
434 
435 	if (err)
436 		goto out;
437 
438 	subreq->base.complete = ahash_def_finup_done2;
439 
440 	err = crypto_ahash_alg(crypto_ahash_reqtfm(req))->final(subreq);
441 	if (err == -EINPROGRESS || err == -EBUSY)
442 		return err;
443 
444 out:
445 	ahash_restore_req(req, err);
446 	return err;
447 }
448 
449 static void ahash_def_finup_done1(void *data, int err)
450 {
451 	struct ahash_request *areq = data;
452 	struct ahash_request *subreq;
453 
454 	if (err == -EINPROGRESS)
455 		goto out;
456 
457 	subreq = areq->priv;
458 	subreq->base.flags &= CRYPTO_TFM_REQ_MAY_BACKLOG;
459 
460 	err = ahash_def_finup_finish1(areq, err);
461 	if (err == -EINPROGRESS || err == -EBUSY)
462 		return;
463 
464 out:
465 	ahash_request_complete(areq, err);
466 }
467 
468 static int ahash_def_finup(struct ahash_request *req)
469 {
470 	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
471 	int err;
472 
473 	err = ahash_save_req(req, ahash_def_finup_done1, true);
474 	if (err)
475 		return err;
476 
477 	err = crypto_ahash_alg(tfm)->update(req->priv);
478 	if (err == -EINPROGRESS || err == -EBUSY)
479 		return err;
480 
481 	return ahash_def_finup_finish1(req, err);
482 }
483 
484 int crypto_ahash_export(struct ahash_request *req, void *out)
485 {
486 	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
487 
488 	if (likely(tfm->using_shash))
489 		return crypto_shash_export(ahash_request_ctx(req), out);
490 	return crypto_ahash_alg(tfm)->export(req, out);
491 }
492 EXPORT_SYMBOL_GPL(crypto_ahash_export);
493 
494 int crypto_ahash_import(struct ahash_request *req, const void *in)
495 {
496 	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
497 
498 	if (likely(tfm->using_shash))
499 		return crypto_shash_import(prepare_shash_desc(req, tfm), in);
500 	if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
501 		return -ENOKEY;
502 	return crypto_ahash_alg(tfm)->import(req, in);
503 }
504 EXPORT_SYMBOL_GPL(crypto_ahash_import);
505 
506 static void crypto_ahash_exit_tfm(struct crypto_tfm *tfm)
507 {
508 	struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
509 	struct ahash_alg *alg = crypto_ahash_alg(hash);
510 
511 	alg->exit_tfm(hash);
512 }
513 
514 static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
515 {
516 	struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
517 	struct ahash_alg *alg = crypto_ahash_alg(hash);
518 
519 	crypto_ahash_set_statesize(hash, alg->halg.statesize);
520 
521 	if (tfm->__crt_alg->cra_type == &crypto_shash_type)
522 		return crypto_init_ahash_using_shash(tfm);
523 
524 	ahash_set_needkey(hash, alg);
525 
526 	if (alg->exit_tfm)
527 		tfm->exit = crypto_ahash_exit_tfm;
528 
529 	return alg->init_tfm ? alg->init_tfm(hash) : 0;
530 }
531 
532 static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
533 {
534 	if (alg->cra_type == &crypto_shash_type)
535 		return sizeof(struct crypto_shash *);
536 
537 	return crypto_alg_extsize(alg);
538 }
539 
540 static void crypto_ahash_free_instance(struct crypto_instance *inst)
541 {
542 	struct ahash_instance *ahash = ahash_instance(inst);
543 
544 	ahash->free(ahash);
545 }
546 
547 static int __maybe_unused crypto_ahash_report(
548 	struct sk_buff *skb, struct crypto_alg *alg)
549 {
550 	struct crypto_report_hash rhash;
551 
552 	memset(&rhash, 0, sizeof(rhash));
553 
554 	strscpy(rhash.type, "ahash", sizeof(rhash.type));
555 
556 	rhash.blocksize = alg->cra_blocksize;
557 	rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
558 
559 	return nla_put(skb, CRYPTOCFGA_REPORT_HASH, sizeof(rhash), &rhash);
560 }
561 
562 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
563 	__maybe_unused;
564 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
565 {
566 	seq_printf(m, "type         : ahash\n");
567 	seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
568 					     "yes" : "no");
569 	seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
570 	seq_printf(m, "digestsize   : %u\n",
571 		   __crypto_hash_alg_common(alg)->digestsize);
572 }
573 
574 static int __maybe_unused crypto_ahash_report_stat(
575 	struct sk_buff *skb, struct crypto_alg *alg)
576 {
577 	return crypto_hash_report_stat(skb, alg, "ahash");
578 }
579 
580 static const struct crypto_type crypto_ahash_type = {
581 	.extsize = crypto_ahash_extsize,
582 	.init_tfm = crypto_ahash_init_tfm,
583 	.free = crypto_ahash_free_instance,
584 #ifdef CONFIG_PROC_FS
585 	.show = crypto_ahash_show,
586 #endif
587 #if IS_ENABLED(CONFIG_CRYPTO_USER)
588 	.report = crypto_ahash_report,
589 #endif
590 #ifdef CONFIG_CRYPTO_STATS
591 	.report_stat = crypto_ahash_report_stat,
592 #endif
593 	.maskclear = ~CRYPTO_ALG_TYPE_MASK,
594 	.maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
595 	.type = CRYPTO_ALG_TYPE_AHASH,
596 	.tfmsize = offsetof(struct crypto_ahash, base),
597 };
598 
599 int crypto_grab_ahash(struct crypto_ahash_spawn *spawn,
600 		      struct crypto_instance *inst,
601 		      const char *name, u32 type, u32 mask)
602 {
603 	spawn->base.frontend = &crypto_ahash_type;
604 	return crypto_grab_spawn(&spawn->base, inst, name, type, mask);
605 }
606 EXPORT_SYMBOL_GPL(crypto_grab_ahash);
607 
608 struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
609 					u32 mask)
610 {
611 	return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
612 }
613 EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
614 
615 int crypto_has_ahash(const char *alg_name, u32 type, u32 mask)
616 {
617 	return crypto_type_has_alg(alg_name, &crypto_ahash_type, type, mask);
618 }
619 EXPORT_SYMBOL_GPL(crypto_has_ahash);
620 
621 static bool crypto_hash_alg_has_setkey(struct hash_alg_common *halg)
622 {
623 	struct crypto_alg *alg = &halg->base;
624 
625 	if (alg->cra_type == &crypto_shash_type)
626 		return crypto_shash_alg_has_setkey(__crypto_shash_alg(alg));
627 
628 	return __crypto_ahash_alg(alg)->setkey != ahash_nosetkey;
629 }
630 
631 struct crypto_ahash *crypto_clone_ahash(struct crypto_ahash *hash)
632 {
633 	struct hash_alg_common *halg = crypto_hash_alg_common(hash);
634 	struct crypto_tfm *tfm = crypto_ahash_tfm(hash);
635 	struct crypto_ahash *nhash;
636 	struct ahash_alg *alg;
637 	int err;
638 
639 	if (!crypto_hash_alg_has_setkey(halg)) {
640 		tfm = crypto_tfm_get(tfm);
641 		if (IS_ERR(tfm))
642 			return ERR_CAST(tfm);
643 
644 		return hash;
645 	}
646 
647 	nhash = crypto_clone_tfm(&crypto_ahash_type, tfm);
648 
649 	if (IS_ERR(nhash))
650 		return nhash;
651 
652 	nhash->reqsize = hash->reqsize;
653 	nhash->statesize = hash->statesize;
654 
655 	if (likely(hash->using_shash)) {
656 		struct crypto_shash **nctx = crypto_ahash_ctx(nhash);
657 		struct crypto_shash *shash;
658 
659 		shash = crypto_clone_shash(ahash_to_shash(hash));
660 		if (IS_ERR(shash)) {
661 			err = PTR_ERR(shash);
662 			goto out_free_nhash;
663 		}
664 		nhash->using_shash = true;
665 		*nctx = shash;
666 		return nhash;
667 	}
668 
669 	err = -ENOSYS;
670 	alg = crypto_ahash_alg(hash);
671 	if (!alg->clone_tfm)
672 		goto out_free_nhash;
673 
674 	err = alg->clone_tfm(nhash, hash);
675 	if (err)
676 		goto out_free_nhash;
677 
678 	return nhash;
679 
680 out_free_nhash:
681 	crypto_free_ahash(nhash);
682 	return ERR_PTR(err);
683 }
684 EXPORT_SYMBOL_GPL(crypto_clone_ahash);
685 
686 static int ahash_prepare_alg(struct ahash_alg *alg)
687 {
688 	struct crypto_alg *base = &alg->halg.base;
689 	int err;
690 
691 	if (alg->halg.statesize == 0)
692 		return -EINVAL;
693 
694 	err = hash_prepare_alg(&alg->halg);
695 	if (err)
696 		return err;
697 
698 	base->cra_type = &crypto_ahash_type;
699 	base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
700 
701 	if (!alg->finup)
702 		alg->finup = ahash_def_finup;
703 	if (!alg->setkey)
704 		alg->setkey = ahash_nosetkey;
705 
706 	return 0;
707 }
708 
709 int crypto_register_ahash(struct ahash_alg *alg)
710 {
711 	struct crypto_alg *base = &alg->halg.base;
712 	int err;
713 
714 	err = ahash_prepare_alg(alg);
715 	if (err)
716 		return err;
717 
718 	return crypto_register_alg(base);
719 }
720 EXPORT_SYMBOL_GPL(crypto_register_ahash);
721 
722 void crypto_unregister_ahash(struct ahash_alg *alg)
723 {
724 	crypto_unregister_alg(&alg->halg.base);
725 }
726 EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
727 
728 int crypto_register_ahashes(struct ahash_alg *algs, int count)
729 {
730 	int i, ret;
731 
732 	for (i = 0; i < count; i++) {
733 		ret = crypto_register_ahash(&algs[i]);
734 		if (ret)
735 			goto err;
736 	}
737 
738 	return 0;
739 
740 err:
741 	for (--i; i >= 0; --i)
742 		crypto_unregister_ahash(&algs[i]);
743 
744 	return ret;
745 }
746 EXPORT_SYMBOL_GPL(crypto_register_ahashes);
747 
748 void crypto_unregister_ahashes(struct ahash_alg *algs, int count)
749 {
750 	int i;
751 
752 	for (i = count - 1; i >= 0; --i)
753 		crypto_unregister_ahash(&algs[i]);
754 }
755 EXPORT_SYMBOL_GPL(crypto_unregister_ahashes);
756 
757 int ahash_register_instance(struct crypto_template *tmpl,
758 			    struct ahash_instance *inst)
759 {
760 	int err;
761 
762 	if (WARN_ON(!inst->free))
763 		return -EINVAL;
764 
765 	err = ahash_prepare_alg(&inst->alg);
766 	if (err)
767 		return err;
768 
769 	return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
770 }
771 EXPORT_SYMBOL_GPL(ahash_register_instance);
772 
773 MODULE_LICENSE("GPL");
774 MODULE_DESCRIPTION("Asynchronous cryptographic hash type");
775