Merge tag 'drm-next-2024-05-25' of https://gitlab.freedesktop.org/drm/kernel
[linux-2.6-block.git] / crypto / ahash.c
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 /*
31  * For an ahash tfm that is using an shash algorithm (instead of an ahash
32  * algorithm), this returns the underlying shash tfm.
33  */
34 static inline struct crypto_shash *ahash_to_shash(struct crypto_ahash *tfm)
35 {
36         return *(struct crypto_shash **)crypto_ahash_ctx(tfm);
37 }
38
39 static inline struct shash_desc *prepare_shash_desc(struct ahash_request *req,
40                                                     struct crypto_ahash *tfm)
41 {
42         struct shash_desc *desc = ahash_request_ctx(req);
43
44         desc->tfm = ahash_to_shash(tfm);
45         return desc;
46 }
47
48 int shash_ahash_update(struct ahash_request *req, struct shash_desc *desc)
49 {
50         struct crypto_hash_walk walk;
51         int nbytes;
52
53         for (nbytes = crypto_hash_walk_first(req, &walk); nbytes > 0;
54              nbytes = crypto_hash_walk_done(&walk, nbytes))
55                 nbytes = crypto_shash_update(desc, walk.data, nbytes);
56
57         return nbytes;
58 }
59 EXPORT_SYMBOL_GPL(shash_ahash_update);
60
61 int shash_ahash_finup(struct ahash_request *req, struct shash_desc *desc)
62 {
63         struct crypto_hash_walk walk;
64         int nbytes;
65
66         nbytes = crypto_hash_walk_first(req, &walk);
67         if (!nbytes)
68                 return crypto_shash_final(desc, req->result);
69
70         do {
71                 nbytes = crypto_hash_walk_last(&walk) ?
72                          crypto_shash_finup(desc, walk.data, nbytes,
73                                             req->result) :
74                          crypto_shash_update(desc, walk.data, nbytes);
75                 nbytes = crypto_hash_walk_done(&walk, nbytes);
76         } while (nbytes > 0);
77
78         return nbytes;
79 }
80 EXPORT_SYMBOL_GPL(shash_ahash_finup);
81
82 int shash_ahash_digest(struct ahash_request *req, struct shash_desc *desc)
83 {
84         unsigned int nbytes = req->nbytes;
85         struct scatterlist *sg;
86         unsigned int offset;
87         int err;
88
89         if (nbytes &&
90             (sg = req->src, offset = sg->offset,
91              nbytes <= min(sg->length, ((unsigned int)(PAGE_SIZE)) - offset))) {
92                 void *data;
93
94                 data = kmap_local_page(sg_page(sg));
95                 err = crypto_shash_digest(desc, data + offset, nbytes,
96                                           req->result);
97                 kunmap_local(data);
98         } else
99                 err = crypto_shash_init(desc) ?:
100                       shash_ahash_finup(req, desc);
101
102         return err;
103 }
104 EXPORT_SYMBOL_GPL(shash_ahash_digest);
105
106 static void crypto_exit_ahash_using_shash(struct crypto_tfm *tfm)
107 {
108         struct crypto_shash **ctx = crypto_tfm_ctx(tfm);
109
110         crypto_free_shash(*ctx);
111 }
112
113 static int crypto_init_ahash_using_shash(struct crypto_tfm *tfm)
114 {
115         struct crypto_alg *calg = tfm->__crt_alg;
116         struct crypto_ahash *crt = __crypto_ahash_cast(tfm);
117         struct crypto_shash **ctx = crypto_tfm_ctx(tfm);
118         struct crypto_shash *shash;
119
120         if (!crypto_mod_get(calg))
121                 return -EAGAIN;
122
123         shash = crypto_create_tfm(calg, &crypto_shash_type);
124         if (IS_ERR(shash)) {
125                 crypto_mod_put(calg);
126                 return PTR_ERR(shash);
127         }
128
129         crt->using_shash = true;
130         *ctx = shash;
131         tfm->exit = crypto_exit_ahash_using_shash;
132
133         crypto_ahash_set_flags(crt, crypto_shash_get_flags(shash) &
134                                     CRYPTO_TFM_NEED_KEY);
135         crt->reqsize = sizeof(struct shash_desc) + crypto_shash_descsize(shash);
136
137         return 0;
138 }
139
140 static int hash_walk_next(struct crypto_hash_walk *walk)
141 {
142         unsigned int offset = walk->offset;
143         unsigned int nbytes = min(walk->entrylen,
144                                   ((unsigned int)(PAGE_SIZE)) - offset);
145
146         walk->data = kmap_local_page(walk->pg);
147         walk->data += offset;
148         walk->entrylen -= nbytes;
149         return nbytes;
150 }
151
152 static int hash_walk_new_entry(struct crypto_hash_walk *walk)
153 {
154         struct scatterlist *sg;
155
156         sg = walk->sg;
157         walk->offset = sg->offset;
158         walk->pg = sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
159         walk->offset = offset_in_page(walk->offset);
160         walk->entrylen = sg->length;
161
162         if (walk->entrylen > walk->total)
163                 walk->entrylen = walk->total;
164         walk->total -= walk->entrylen;
165
166         return hash_walk_next(walk);
167 }
168
169 int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
170 {
171         walk->data -= walk->offset;
172
173         kunmap_local(walk->data);
174         crypto_yield(walk->flags);
175
176         if (err)
177                 return err;
178
179         if (walk->entrylen) {
180                 walk->offset = 0;
181                 walk->pg++;
182                 return hash_walk_next(walk);
183         }
184
185         if (!walk->total)
186                 return 0;
187
188         walk->sg = sg_next(walk->sg);
189
190         return hash_walk_new_entry(walk);
191 }
192 EXPORT_SYMBOL_GPL(crypto_hash_walk_done);
193
194 int crypto_hash_walk_first(struct ahash_request *req,
195                            struct crypto_hash_walk *walk)
196 {
197         walk->total = req->nbytes;
198
199         if (!walk->total) {
200                 walk->entrylen = 0;
201                 return 0;
202         }
203
204         walk->sg = req->src;
205         walk->flags = req->base.flags;
206
207         return hash_walk_new_entry(walk);
208 }
209 EXPORT_SYMBOL_GPL(crypto_hash_walk_first);
210
211 static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
212                           unsigned int keylen)
213 {
214         return -ENOSYS;
215 }
216
217 static void ahash_set_needkey(struct crypto_ahash *tfm, struct ahash_alg *alg)
218 {
219         if (alg->setkey != ahash_nosetkey &&
220             !(alg->halg.base.cra_flags & CRYPTO_ALG_OPTIONAL_KEY))
221                 crypto_ahash_set_flags(tfm, CRYPTO_TFM_NEED_KEY);
222 }
223
224 int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
225                         unsigned int keylen)
226 {
227         if (likely(tfm->using_shash)) {
228                 struct crypto_shash *shash = ahash_to_shash(tfm);
229                 int err;
230
231                 err = crypto_shash_setkey(shash, key, keylen);
232                 if (unlikely(err)) {
233                         crypto_ahash_set_flags(tfm,
234                                                crypto_shash_get_flags(shash) &
235                                                CRYPTO_TFM_NEED_KEY);
236                         return err;
237                 }
238         } else {
239                 struct ahash_alg *alg = crypto_ahash_alg(tfm);
240                 int err;
241
242                 err = alg->setkey(tfm, key, keylen);
243                 if (unlikely(err)) {
244                         ahash_set_needkey(tfm, alg);
245                         return err;
246                 }
247         }
248         crypto_ahash_clear_flags(tfm, CRYPTO_TFM_NEED_KEY);
249         return 0;
250 }
251 EXPORT_SYMBOL_GPL(crypto_ahash_setkey);
252
253 int crypto_ahash_init(struct ahash_request *req)
254 {
255         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
256
257         if (likely(tfm->using_shash))
258                 return crypto_shash_init(prepare_shash_desc(req, tfm));
259         if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
260                 return -ENOKEY;
261         return crypto_ahash_alg(tfm)->init(req);
262 }
263 EXPORT_SYMBOL_GPL(crypto_ahash_init);
264
265 static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt,
266                           bool has_state)
267 {
268         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
269         unsigned int ds = crypto_ahash_digestsize(tfm);
270         struct ahash_request *subreq;
271         unsigned int subreq_size;
272         unsigned int reqsize;
273         u8 *result;
274         gfp_t gfp;
275         u32 flags;
276
277         subreq_size = sizeof(*subreq);
278         reqsize = crypto_ahash_reqsize(tfm);
279         reqsize = ALIGN(reqsize, crypto_tfm_ctx_alignment());
280         subreq_size += reqsize;
281         subreq_size += ds;
282
283         flags = ahash_request_flags(req);
284         gfp = (flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?  GFP_KERNEL : GFP_ATOMIC;
285         subreq = kmalloc(subreq_size, gfp);
286         if (!subreq)
287                 return -ENOMEM;
288
289         ahash_request_set_tfm(subreq, tfm);
290         ahash_request_set_callback(subreq, flags, cplt, req);
291
292         result = (u8 *)(subreq + 1) + reqsize;
293
294         ahash_request_set_crypt(subreq, req->src, result, req->nbytes);
295
296         if (has_state) {
297                 void *state;
298
299                 state = kmalloc(crypto_ahash_statesize(tfm), gfp);
300                 if (!state) {
301                         kfree(subreq);
302                         return -ENOMEM;
303                 }
304
305                 crypto_ahash_export(req, state);
306                 crypto_ahash_import(subreq, state);
307                 kfree_sensitive(state);
308         }
309
310         req->priv = subreq;
311
312         return 0;
313 }
314
315 static void ahash_restore_req(struct ahash_request *req, int err)
316 {
317         struct ahash_request *subreq = req->priv;
318
319         if (!err)
320                 memcpy(req->result, subreq->result,
321                        crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
322
323         req->priv = NULL;
324
325         kfree_sensitive(subreq);
326 }
327
328 int crypto_ahash_update(struct ahash_request *req)
329 {
330         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
331
332         if (likely(tfm->using_shash))
333                 return shash_ahash_update(req, ahash_request_ctx(req));
334
335         return crypto_ahash_alg(tfm)->update(req);
336 }
337 EXPORT_SYMBOL_GPL(crypto_ahash_update);
338
339 int crypto_ahash_final(struct ahash_request *req)
340 {
341         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
342
343         if (likely(tfm->using_shash))
344                 return crypto_shash_final(ahash_request_ctx(req), req->result);
345
346         return crypto_ahash_alg(tfm)->final(req);
347 }
348 EXPORT_SYMBOL_GPL(crypto_ahash_final);
349
350 int crypto_ahash_finup(struct ahash_request *req)
351 {
352         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
353
354         if (likely(tfm->using_shash))
355                 return shash_ahash_finup(req, ahash_request_ctx(req));
356
357         return crypto_ahash_alg(tfm)->finup(req);
358 }
359 EXPORT_SYMBOL_GPL(crypto_ahash_finup);
360
361 int crypto_ahash_digest(struct ahash_request *req)
362 {
363         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
364
365         if (likely(tfm->using_shash))
366                 return shash_ahash_digest(req, prepare_shash_desc(req, tfm));
367
368         if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
369                 return -ENOKEY;
370
371         return crypto_ahash_alg(tfm)->digest(req);
372 }
373 EXPORT_SYMBOL_GPL(crypto_ahash_digest);
374
375 static void ahash_def_finup_done2(void *data, int err)
376 {
377         struct ahash_request *areq = data;
378
379         if (err == -EINPROGRESS)
380                 return;
381
382         ahash_restore_req(areq, err);
383
384         ahash_request_complete(areq, err);
385 }
386
387 static int ahash_def_finup_finish1(struct ahash_request *req, int err)
388 {
389         struct ahash_request *subreq = req->priv;
390
391         if (err)
392                 goto out;
393
394         subreq->base.complete = ahash_def_finup_done2;
395
396         err = crypto_ahash_alg(crypto_ahash_reqtfm(req))->final(subreq);
397         if (err == -EINPROGRESS || err == -EBUSY)
398                 return err;
399
400 out:
401         ahash_restore_req(req, err);
402         return err;
403 }
404
405 static void ahash_def_finup_done1(void *data, int err)
406 {
407         struct ahash_request *areq = data;
408         struct ahash_request *subreq;
409
410         if (err == -EINPROGRESS)
411                 goto out;
412
413         subreq = areq->priv;
414         subreq->base.flags &= CRYPTO_TFM_REQ_MAY_BACKLOG;
415
416         err = ahash_def_finup_finish1(areq, err);
417         if (err == -EINPROGRESS || err == -EBUSY)
418                 return;
419
420 out:
421         ahash_request_complete(areq, err);
422 }
423
424 static int ahash_def_finup(struct ahash_request *req)
425 {
426         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
427         int err;
428
429         err = ahash_save_req(req, ahash_def_finup_done1, true);
430         if (err)
431                 return err;
432
433         err = crypto_ahash_alg(tfm)->update(req->priv);
434         if (err == -EINPROGRESS || err == -EBUSY)
435                 return err;
436
437         return ahash_def_finup_finish1(req, err);
438 }
439
440 int crypto_ahash_export(struct ahash_request *req, void *out)
441 {
442         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
443
444         if (likely(tfm->using_shash))
445                 return crypto_shash_export(ahash_request_ctx(req), out);
446         return crypto_ahash_alg(tfm)->export(req, out);
447 }
448 EXPORT_SYMBOL_GPL(crypto_ahash_export);
449
450 int crypto_ahash_import(struct ahash_request *req, const void *in)
451 {
452         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
453
454         if (likely(tfm->using_shash))
455                 return crypto_shash_import(prepare_shash_desc(req, tfm), in);
456         if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
457                 return -ENOKEY;
458         return crypto_ahash_alg(tfm)->import(req, in);
459 }
460 EXPORT_SYMBOL_GPL(crypto_ahash_import);
461
462 static void crypto_ahash_exit_tfm(struct crypto_tfm *tfm)
463 {
464         struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
465         struct ahash_alg *alg = crypto_ahash_alg(hash);
466
467         alg->exit_tfm(hash);
468 }
469
470 static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
471 {
472         struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
473         struct ahash_alg *alg = crypto_ahash_alg(hash);
474
475         crypto_ahash_set_statesize(hash, alg->halg.statesize);
476
477         if (tfm->__crt_alg->cra_type == &crypto_shash_type)
478                 return crypto_init_ahash_using_shash(tfm);
479
480         ahash_set_needkey(hash, alg);
481
482         if (alg->exit_tfm)
483                 tfm->exit = crypto_ahash_exit_tfm;
484
485         return alg->init_tfm ? alg->init_tfm(hash) : 0;
486 }
487
488 static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
489 {
490         if (alg->cra_type == &crypto_shash_type)
491                 return sizeof(struct crypto_shash *);
492
493         return crypto_alg_extsize(alg);
494 }
495
496 static void crypto_ahash_free_instance(struct crypto_instance *inst)
497 {
498         struct ahash_instance *ahash = ahash_instance(inst);
499
500         ahash->free(ahash);
501 }
502
503 static int __maybe_unused crypto_ahash_report(
504         struct sk_buff *skb, struct crypto_alg *alg)
505 {
506         struct crypto_report_hash rhash;
507
508         memset(&rhash, 0, sizeof(rhash));
509
510         strscpy(rhash.type, "ahash", sizeof(rhash.type));
511
512         rhash.blocksize = alg->cra_blocksize;
513         rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
514
515         return nla_put(skb, CRYPTOCFGA_REPORT_HASH, sizeof(rhash), &rhash);
516 }
517
518 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
519         __maybe_unused;
520 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
521 {
522         seq_printf(m, "type         : ahash\n");
523         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
524                                              "yes" : "no");
525         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
526         seq_printf(m, "digestsize   : %u\n",
527                    __crypto_hash_alg_common(alg)->digestsize);
528 }
529
530 static const struct crypto_type crypto_ahash_type = {
531         .extsize = crypto_ahash_extsize,
532         .init_tfm = crypto_ahash_init_tfm,
533         .free = crypto_ahash_free_instance,
534 #ifdef CONFIG_PROC_FS
535         .show = crypto_ahash_show,
536 #endif
537 #if IS_ENABLED(CONFIG_CRYPTO_USER)
538         .report = crypto_ahash_report,
539 #endif
540         .maskclear = ~CRYPTO_ALG_TYPE_MASK,
541         .maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
542         .type = CRYPTO_ALG_TYPE_AHASH,
543         .tfmsize = offsetof(struct crypto_ahash, base),
544 };
545
546 int crypto_grab_ahash(struct crypto_ahash_spawn *spawn,
547                       struct crypto_instance *inst,
548                       const char *name, u32 type, u32 mask)
549 {
550         spawn->base.frontend = &crypto_ahash_type;
551         return crypto_grab_spawn(&spawn->base, inst, name, type, mask);
552 }
553 EXPORT_SYMBOL_GPL(crypto_grab_ahash);
554
555 struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
556                                         u32 mask)
557 {
558         return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
559 }
560 EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
561
562 int crypto_has_ahash(const char *alg_name, u32 type, u32 mask)
563 {
564         return crypto_type_has_alg(alg_name, &crypto_ahash_type, type, mask);
565 }
566 EXPORT_SYMBOL_GPL(crypto_has_ahash);
567
568 static bool crypto_hash_alg_has_setkey(struct hash_alg_common *halg)
569 {
570         struct crypto_alg *alg = &halg->base;
571
572         if (alg->cra_type == &crypto_shash_type)
573                 return crypto_shash_alg_has_setkey(__crypto_shash_alg(alg));
574
575         return __crypto_ahash_alg(alg)->setkey != ahash_nosetkey;
576 }
577
578 struct crypto_ahash *crypto_clone_ahash(struct crypto_ahash *hash)
579 {
580         struct hash_alg_common *halg = crypto_hash_alg_common(hash);
581         struct crypto_tfm *tfm = crypto_ahash_tfm(hash);
582         struct crypto_ahash *nhash;
583         struct ahash_alg *alg;
584         int err;
585
586         if (!crypto_hash_alg_has_setkey(halg)) {
587                 tfm = crypto_tfm_get(tfm);
588                 if (IS_ERR(tfm))
589                         return ERR_CAST(tfm);
590
591                 return hash;
592         }
593
594         nhash = crypto_clone_tfm(&crypto_ahash_type, tfm);
595
596         if (IS_ERR(nhash))
597                 return nhash;
598
599         nhash->reqsize = hash->reqsize;
600         nhash->statesize = hash->statesize;
601
602         if (likely(hash->using_shash)) {
603                 struct crypto_shash **nctx = crypto_ahash_ctx(nhash);
604                 struct crypto_shash *shash;
605
606                 shash = crypto_clone_shash(ahash_to_shash(hash));
607                 if (IS_ERR(shash)) {
608                         err = PTR_ERR(shash);
609                         goto out_free_nhash;
610                 }
611                 nhash->using_shash = true;
612                 *nctx = shash;
613                 return nhash;
614         }
615
616         err = -ENOSYS;
617         alg = crypto_ahash_alg(hash);
618         if (!alg->clone_tfm)
619                 goto out_free_nhash;
620
621         err = alg->clone_tfm(nhash, hash);
622         if (err)
623                 goto out_free_nhash;
624
625         return nhash;
626
627 out_free_nhash:
628         crypto_free_ahash(nhash);
629         return ERR_PTR(err);
630 }
631 EXPORT_SYMBOL_GPL(crypto_clone_ahash);
632
633 static int ahash_prepare_alg(struct ahash_alg *alg)
634 {
635         struct crypto_alg *base = &alg->halg.base;
636         int err;
637
638         if (alg->halg.statesize == 0)
639                 return -EINVAL;
640
641         err = hash_prepare_alg(&alg->halg);
642         if (err)
643                 return err;
644
645         base->cra_type = &crypto_ahash_type;
646         base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
647
648         if (!alg->finup)
649                 alg->finup = ahash_def_finup;
650         if (!alg->setkey)
651                 alg->setkey = ahash_nosetkey;
652
653         return 0;
654 }
655
656 int crypto_register_ahash(struct ahash_alg *alg)
657 {
658         struct crypto_alg *base = &alg->halg.base;
659         int err;
660
661         err = ahash_prepare_alg(alg);
662         if (err)
663                 return err;
664
665         return crypto_register_alg(base);
666 }
667 EXPORT_SYMBOL_GPL(crypto_register_ahash);
668
669 void crypto_unregister_ahash(struct ahash_alg *alg)
670 {
671         crypto_unregister_alg(&alg->halg.base);
672 }
673 EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
674
675 int crypto_register_ahashes(struct ahash_alg *algs, int count)
676 {
677         int i, ret;
678
679         for (i = 0; i < count; i++) {
680                 ret = crypto_register_ahash(&algs[i]);
681                 if (ret)
682                         goto err;
683         }
684
685         return 0;
686
687 err:
688         for (--i; i >= 0; --i)
689                 crypto_unregister_ahash(&algs[i]);
690
691         return ret;
692 }
693 EXPORT_SYMBOL_GPL(crypto_register_ahashes);
694
695 void crypto_unregister_ahashes(struct ahash_alg *algs, int count)
696 {
697         int i;
698
699         for (i = count - 1; i >= 0; --i)
700                 crypto_unregister_ahash(&algs[i]);
701 }
702 EXPORT_SYMBOL_GPL(crypto_unregister_ahashes);
703
704 int ahash_register_instance(struct crypto_template *tmpl,
705                             struct ahash_instance *inst)
706 {
707         int err;
708
709         if (WARN_ON(!inst->free))
710                 return -EINVAL;
711
712         err = ahash_prepare_alg(&inst->alg);
713         if (err)
714                 return err;
715
716         return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
717 }
718 EXPORT_SYMBOL_GPL(ahash_register_instance);
719
720 MODULE_LICENSE("GPL");
721 MODULE_DESCRIPTION("Asynchronous cryptographic hash type");