crypto/ahash.c

   1 /*
   2  * Asynchronous Cryptographic Hash operations.
   3  *
   4  * This is the asynchronous version of hash.c with notification of
   5  * completion via a callback.
   6  *
   7  * Copyright (c) 2008 Loc Ho <lho@amcc.com>
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU General Public License as published by the Free
  11  * Software Foundation; either version 2 of the License, or (at your option)
  12  * any later version.
  13  *
  14  */
  15
  16 #include <crypto/internal/hash.h>
  17 #include <crypto/scatterwalk.h>
  18 #include <linux/bug.h>
  19 #include <linux/err.h>
  20 #include <linux/kernel.h>
  21 #include <linux/module.h>
  22 #include <linux/sched.h>
  23 #include <linux/slab.h>
  24 #include <linux/seq_file.h>
  25 #include <linux/cryptouser.h>
  26 #include <linux/compiler.h>
  27 #include <net/netlink.h>
  28
  29 #include "internal.h"
  30
  31 struct ahash_request_priv {
  32         crypto_completion_t complete;
  33         void *data;
  34         u8 *result;
  35         u32 flags;
  36         void *ubuf[] CRYPTO_MINALIGN_ATTR;
  37 };
  38
  39 static inline struct ahash_alg *crypto_ahash_alg(struct crypto_ahash *hash)
  40 {
  41         return container_of(crypto_hash_alg_common(hash), struct ahash_alg,
  42                             halg);
  43 }
  44
  45 static int hash_walk_next(struct crypto_hash_walk *walk)
  46 {
  47         unsigned int alignmask = walk->alignmask;
  48         unsigned int offset = walk->offset;
  49         unsigned int nbytes = min(walk->entrylen,
  50                                   ((unsigned int)(PAGE_SIZE)) - offset);
  51
  52         if (walk->flags & CRYPTO_ALG_ASYNC)
  53                 walk->data = kmap(walk->pg);
  54         else
  55                 walk->data = kmap_atomic(walk->pg);
  56         walk->data += offset;
  57
  58         if (offset & alignmask) {
  59                 unsigned int unaligned = alignmask + 1 - (offset & alignmask);
  60
  61                 if (nbytes > unaligned)
  62                         nbytes = unaligned;
  63         }
  64
  65         walk->entrylen -= nbytes;
  66         return nbytes;
  67 }
  68
  69 static int hash_walk_new_entry(struct crypto_hash_walk *walk)
  70 {
  71         struct scatterlist *sg;
  72
  73         sg = walk->sg;
  74         walk->offset = sg->offset;
  75         walk->pg = sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
  76         walk->offset = offset_in_page(walk->offset);
  77         walk->entrylen = sg->length;
  78
  79         if (walk->entrylen > walk->total)
  80                 walk->entrylen = walk->total;
  81         walk->total -= walk->entrylen;
  82
  83         return hash_walk_next(walk);
  84 }
  85
  86 int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
  87 {
  88         unsigned int alignmask = walk->alignmask;
  89
  90         walk->data -= walk->offset;
  91
  92         if (walk->entrylen && (walk->offset & alignmask) && !err) {
  93                 unsigned int nbytes;
  94
  95                 walk->offset = ALIGN(walk->offset, alignmask + 1);
  96                 nbytes = min(walk->entrylen,
  97                              (unsigned int)(PAGE_SIZE - walk->offset));
  98                 if (nbytes) {
  99                         walk->entrylen -= nbytes;
 100                         walk->data += walk->offset;
 101                         return nbytes;
 102                 }
 103         }
 104
 105         if (walk->flags & CRYPTO_ALG_ASYNC)
 106                 kunmap(walk->pg);
 107         else {
 108                 kunmap_atomic(walk->data);
 109                 /*
 110                  * The may sleep test only makes sense for sync users.
 111                  * Async users don't need to sleep here anyway.
 112                  */
 113                 crypto_yield(walk->flags);
 114         }
 115
 116         if (err)
 117                 return err;
 118
 119         if (walk->entrylen) {
 120                 walk->offset = 0;
 121                 walk->pg++;
 122                 return hash_walk_next(walk);
 123         }
 124
 125         if (!walk->total)
 126                 return 0;
 127
 128         walk->sg = sg_next(walk->sg);
 129
 130         return hash_walk_new_entry(walk);
 131 }
 132 EXPORT_SYMBOL_GPL(crypto_hash_walk_done);
 133
 134 int crypto_hash_walk_first(struct ahash_request *req,
 135                            struct crypto_hash_walk *walk)
 136 {
 137         walk->total = req->nbytes;
 138
 139         if (!walk->total) {
 140                 walk->entrylen = 0;
 141                 return 0;
 142         }
 143
 144         walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
 145         walk->sg = req->src;
 146         walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK;
 147
 148         return hash_walk_new_entry(walk);
 149 }
 150 EXPORT_SYMBOL_GPL(crypto_hash_walk_first);
 151
 152 int crypto_ahash_walk_first(struct ahash_request *req,
 153                             struct crypto_hash_walk *walk)
 154 {
 155         walk->total = req->nbytes;
 156
 157         if (!walk->total) {
 158                 walk->entrylen = 0;
 159                 return 0;
 160         }
 161
 162         walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
 163         walk->sg = req->src;
 164         walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK;
 165         walk->flags |= CRYPTO_ALG_ASYNC;
 166
 167         BUILD_BUG_ON(CRYPTO_TFM_REQ_MASK & CRYPTO_ALG_ASYNC);
 168
 169         return hash_walk_new_entry(walk);
 170 }
 171 EXPORT_SYMBOL_GPL(crypto_ahash_walk_first);
 172
 173 static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,
 174                                 unsigned int keylen)
 175 {
 176         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 177         int ret;
 178         u8 *buffer, *alignbuffer;
 179         unsigned long absize;
 180
 181         absize = keylen + alignmask;
 182         buffer = kmalloc(absize, GFP_KERNEL);
 183         if (!buffer)
 184                 return -ENOMEM;
 185
 186         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 187         memcpy(alignbuffer, key, keylen);
 188         ret = tfm->setkey(tfm, alignbuffer, keylen);
 189         kzfree(buffer);
 190         return ret;
 191 }
 192
 193 static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
 194                           unsigned int keylen)
 195 {
 196         return -ENOSYS;
 197 }
 198
 199 static void ahash_set_needkey(struct crypto_ahash *tfm)
 200 {
 201         const struct hash_alg_common *alg = crypto_hash_alg_common(tfm);
 202
 203         if (tfm->setkey != ahash_nosetkey &&
 204             !(alg->base.cra_flags & CRYPTO_ALG_OPTIONAL_KEY))
 205                 crypto_ahash_set_flags(tfm, CRYPTO_TFM_NEED_KEY);
 206 }
 207
 208 int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
 209                         unsigned int keylen)
 210 {
 211         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 212         int err;
 213
 214         if ((unsigned long)key & alignmask)
 215                 err = ahash_setkey_unaligned(tfm, key, keylen);
 216         else
 217                 err = tfm->setkey(tfm, key, keylen);
 218
 219         if (unlikely(err)) {
 220                 ahash_set_needkey(tfm);
 221                 return err;
 222         }
 223
 224         crypto_ahash_clear_flags(tfm, CRYPTO_TFM_NEED_KEY);
 225         return 0;
 226 }
 227 EXPORT_SYMBOL_GPL(crypto_ahash_setkey);
 228
 229 static inline unsigned int ahash_align_buffer_size(unsigned len,
 230                                                    unsigned long mask)
 231 {
 232         return len + (mask & ~(crypto_tfm_ctx_alignment() - 1));
 233 }
 234
 235 static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt)
 236 {
 237         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 238         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 239         unsigned int ds = crypto_ahash_digestsize(tfm);
 240         struct ahash_request_priv *priv;
 241
 242         priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
 243                        (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
 244                        GFP_KERNEL : GFP_ATOMIC);
 245         if (!priv)
 246                 return -ENOMEM;
 247
 248         /*
 249          * WARNING: Voodoo programming below!
 250          *
 251          * The code below is obscure and hard to understand, thus explanation
 252          * is necessary. See include/crypto/hash.h and include/linux/crypto.h
 253          * to understand the layout of structures used here!
 254          *
 255          * The code here will replace portions of the ORIGINAL request with
 256          * pointers to new code and buffers so the hashing operation can store
 257          * the result in aligned buffer. We will call the modified request
 258          * an ADJUSTED request.
 259          *
 260          * The newly mangled request will look as such:
 261          *
 262          * req {
 263          *   .result        = ADJUSTED[new aligned buffer]
 264          *   .base.complete = ADJUSTED[pointer to completion function]
 265          *   .base.data     = ADJUSTED[*req (pointer to self)]
 266          *   .priv          = ADJUSTED[new priv] {
 267          *           .result   = ORIGINAL(result)
 268          *           .complete = ORIGINAL(base.complete)
 269          *           .data     = ORIGINAL(base.data)
 270          *   }
 271          */
 272
 273         priv->result = req->result;
 274         priv->complete = req->base.complete;
 275         priv->data = req->base.data;
 276         priv->flags = req->base.flags;
 277
 278         /*
 279          * WARNING: We do not backup req->priv here! The req->priv
 280          *          is for internal use of the Crypto API and the
 281          *          user must _NOT_ _EVER_ depend on it's content!
 282          */
 283
 284         req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
 285         req->base.complete = cplt;
 286         req->base.data = req;
 287         req->priv = priv;
 288
 289         return 0;
 290 }
 291
 292 static void ahash_restore_req(struct ahash_request *req, int err)
 293 {
 294         struct ahash_request_priv *priv = req->priv;
 295
 296         if (!err)
 297                 memcpy(priv->result, req->result,
 298                        crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
 299
 300         /* Restore the original crypto request. */
 301         req->result = priv->result;
 302
 303         ahash_request_set_callback(req, priv->flags,
 304                                    priv->complete, priv->data);
 305         req->priv = NULL;
 306
 307         /* Free the req->priv.priv from the ADJUSTED request. */
 308         kzfree(priv);
 309 }
 310
 311 static void ahash_notify_einprogress(struct ahash_request *req)
 312 {
 313         struct ahash_request_priv *priv = req->priv;
 314         struct crypto_async_request oreq;
 315
 316         oreq.data = priv->data;
 317
 318         priv->complete(&oreq, -EINPROGRESS);
 319 }
 320
 321 static void ahash_op_unaligned_done(struct crypto_async_request *req, int err)
 322 {
 323         struct ahash_request *areq = req->data;
 324
 325         if (err == -EINPROGRESS) {
 326                 ahash_notify_einprogress(areq);
 327                 return;
 328         }
 329
 330         /*
 331          * Restore the original request, see ahash_op_unaligned() for what
 332          * goes where.
 333          *
 334          * The "struct ahash_request *req" here is in fact the "req.base"
 335          * from the ADJUSTED request from ahash_op_unaligned(), thus as it
 336          * is a pointer to self, it is also the ADJUSTED "req" .
 337          */
 338
 339         /* First copy req->result into req->priv.result */
 340         ahash_restore_req(areq, err);
 341
 342         /* Complete the ORIGINAL request. */
 343         areq->base.complete(&areq->base, err);
 344 }
 345
 346 static int ahash_op_unaligned(struct ahash_request *req,
 347                               int (*op)(struct ahash_request *))
 348 {
 349         int err;
 350
 351         err = ahash_save_req(req, ahash_op_unaligned_done);
 352         if (err)
 353                 return err;
 354
 355         err = op(req);
 356         if (err == -EINPROGRESS || err == -EBUSY)
 357                 return err;
 358
 359         ahash_restore_req(req, err);
 360
 361         return err;
 362 }
 363
 364 static int crypto_ahash_op(struct ahash_request *req,
 365                            int (*op)(struct ahash_request *))
 366 {
 367         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 368         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 369
 370         if ((unsigned long)req->result & alignmask)
 371                 return ahash_op_unaligned(req, op);
 372
 373         return op(req);
 374 }
 375
 376 int crypto_ahash_final(struct ahash_request *req)
 377 {
 378         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
 379 }
 380 EXPORT_SYMBOL_GPL(crypto_ahash_final);
 381
 382 int crypto_ahash_finup(struct ahash_request *req)
 383 {
 384         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
 385 }
 386 EXPORT_SYMBOL_GPL(crypto_ahash_finup);
 387
 388 int crypto_ahash_digest(struct ahash_request *req)
 389 {
 390         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 391
 392         if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
 393                 return -ENOKEY;
 394
 395         return crypto_ahash_op(req, tfm->digest);
 396 }
 397 EXPORT_SYMBOL_GPL(crypto_ahash_digest);
 398
 399 static void ahash_def_finup_done2(struct crypto_async_request *req, int err)
 400 {
 401         struct ahash_request *areq = req->data;
 402
 403         if (err == -EINPROGRESS)
 404                 return;
 405
 406         ahash_restore_req(areq, err);
 407
 408         areq->base.complete(&areq->base, err);
 409 }
 410
 411 static int ahash_def_finup_finish1(struct ahash_request *req, int err)
 412 {
 413         if (err)
 414                 goto out;
 415
 416         req->base.complete = ahash_def_finup_done2;
 417
 418         err = crypto_ahash_reqtfm(req)->final(req);
 419         if (err == -EINPROGRESS || err == -EBUSY)
 420                 return err;
 421
 422 out:
 423         ahash_restore_req(req, err);
 424         return err;
 425 }
 426
 427 static void ahash_def_finup_done1(struct crypto_async_request *req, int err)
 428 {
 429         struct ahash_request *areq = req->data;
 430
 431         if (err == -EINPROGRESS) {
 432                 ahash_notify_einprogress(areq);
 433                 return;
 434         }
 435
 436         areq->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
 437
 438         err = ahash_def_finup_finish1(areq, err);
 439         if (areq->priv)
 440                 return;
 441
 442         areq->base.complete(&areq->base, err);
 443 }
 444
 445 static int ahash_def_finup(struct ahash_request *req)
 446 {
 447         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 448         int err;
 449
 450         err = ahash_save_req(req, ahash_def_finup_done1);
 451         if (err)
 452                 return err;
 453
 454         err = tfm->update(req);
 455         if (err == -EINPROGRESS || err == -EBUSY)
 456                 return err;
 457
 458         return ahash_def_finup_finish1(req, err);
 459 }
 460
 461 static int ahash_no_export(struct ahash_request *req, void *out)
 462 {
 463         return -ENOSYS;
 464 }
 465
 466 static int ahash_no_import(struct ahash_request *req, const void *in)
 467 {
 468         return -ENOSYS;
 469 }
 470
 471 static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
 472 {
 473         struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
 474         struct ahash_alg *alg = crypto_ahash_alg(hash);
 475
 476         hash->setkey = ahash_nosetkey;
 477         hash->export = ahash_no_export;
 478         hash->import = ahash_no_import;
 479
 480         if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
 481                 return crypto_init_shash_ops_async(tfm);
 482
 483         hash->init = alg->init;
 484         hash->update = alg->update;
 485         hash->final = alg->final;
 486         hash->finup = alg->finup ?: ahash_def_finup;
 487         hash->digest = alg->digest;
 488
 489         if (alg->setkey) {
 490                 hash->setkey = alg->setkey;
 491                 ahash_set_needkey(hash);
 492         }
 493         if (alg->export)
 494                 hash->export = alg->export;
 495         if (alg->import)
 496                 hash->import = alg->import;
 497
 498         return 0;
 499 }
 500
 501 static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
 502 {
 503         if (alg->cra_type != &crypto_ahash_type)
 504                 return sizeof(struct crypto_shash *);
 505
 506         return crypto_alg_extsize(alg);
 507 }
 508
 509 #ifdef CONFIG_NET
 510 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 511 {
 512         struct crypto_report_hash rhash;
 513
 514         strncpy(rhash.type, "ahash", sizeof(rhash.type));
 515
 516         rhash.blocksize = alg->cra_blocksize;
 517         rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
 518
 519         if (nla_put(skb, CRYPTOCFGA_REPORT_HASH,
 520                     sizeof(struct crypto_report_hash), &rhash))
 521                 goto nla_put_failure;
 522         return 0;
 523
 524 nla_put_failure:
 525         return -EMSGSIZE;
 526 }
 527 #else
 528 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 529 {
 530         return -ENOSYS;
 531 }
 532 #endif
 533
 534 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 535         __maybe_unused;
 536 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 537 {
 538         seq_printf(m, "type         : ahash\n");
 539         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 540                                              "yes" : "no");
 541         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 542         seq_printf(m, "digestsize   : %u\n",
 543                    __crypto_hash_alg_common(alg)->digestsize);
 544 }
 545
 546 const struct crypto_type crypto_ahash_type = {
 547         .extsize = crypto_ahash_extsize,
 548         .init_tfm = crypto_ahash_init_tfm,
 549 #ifdef CONFIG_PROC_FS
 550         .show = crypto_ahash_show,
 551 #endif
 552         .report = crypto_ahash_report,
 553         .maskclear = ~CRYPTO_ALG_TYPE_MASK,
 554         .maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
 555         .type = CRYPTO_ALG_TYPE_AHASH,
 556         .tfmsize = offsetof(struct crypto_ahash, base),
 557 };
 558 EXPORT_SYMBOL_GPL(crypto_ahash_type);
 559
 560 struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
 561                                         u32 mask)
 562 {
 563         return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
 564 }
 565 EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
 566
 567 int crypto_has_ahash(const char *alg_name, u32 type, u32 mask)
 568 {
 569         return crypto_type_has_alg(alg_name, &crypto_ahash_type, type, mask);
 570 }
 571 EXPORT_SYMBOL_GPL(crypto_has_ahash);
 572
 573 static int ahash_prepare_alg(struct ahash_alg *alg)
 574 {
 575         struct crypto_alg *base = &alg->halg.base;
 576
 577         if (alg->halg.digestsize > PAGE_SIZE / 8 ||
 578             alg->halg.statesize > PAGE_SIZE / 8 ||
 579             alg->halg.statesize == 0)
 580                 return -EINVAL;
 581
 582         base->cra_type = &crypto_ahash_type;
 583         base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
 584         base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
 585
 586         return 0;
 587 }
 588
 589 int crypto_register_ahash(struct ahash_alg *alg)
 590 {
 591         struct crypto_alg *base = &alg->halg.base;
 592         int err;
 593
 594         err = ahash_prepare_alg(alg);
 595         if (err)
 596                 return err;
 597
 598         return crypto_register_alg(base);
 599 }
 600 EXPORT_SYMBOL_GPL(crypto_register_ahash);
 601
 602 int crypto_unregister_ahash(struct ahash_alg *alg)
 603 {
 604         return crypto_unregister_alg(&alg->halg.base);
 605 }
 606 EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
 607
 608 int crypto_register_ahashes(struct ahash_alg *algs, int count)
 609 {
 610         int i, ret;
 611
 612         for (i = 0; i < count; i++) {
 613                 ret = crypto_register_ahash(&algs[i]);
 614                 if (ret)
 615                         goto err;
 616         }
 617
 618         return 0;
 619
 620 err:
 621         for (--i; i >= 0; --i)
 622                 crypto_unregister_ahash(&algs[i]);
 623
 624         return ret;
 625 }
 626 EXPORT_SYMBOL_GPL(crypto_register_ahashes);
 627
 628 void crypto_unregister_ahashes(struct ahash_alg *algs, int count)
 629 {
 630         int i;
 631
 632         for (i = count - 1; i >= 0; --i)
 633                 crypto_unregister_ahash(&algs[i]);
 634 }
 635 EXPORT_SYMBOL_GPL(crypto_unregister_ahashes);
 636
 637 int ahash_register_instance(struct crypto_template *tmpl,
 638                             struct ahash_instance *inst)
 639 {
 640         int err;
 641
 642         err = ahash_prepare_alg(&inst->alg);
 643         if (err)
 644                 return err;
 645
 646         return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
 647 }
 648 EXPORT_SYMBOL_GPL(ahash_register_instance);
 649
 650 void ahash_free_instance(struct crypto_instance *inst)
 651 {
 652         crypto_drop_spawn(crypto_instance_ctx(inst));
 653         kfree(ahash_instance(inst));
 654 }
 655 EXPORT_SYMBOL_GPL(ahash_free_instance);
 656
 657 int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
 658                             struct hash_alg_common *alg,
 659                             struct crypto_instance *inst)
 660 {
 661         return crypto_init_spawn2(&spawn->base, &alg->base, inst,
 662                                   &crypto_ahash_type);
 663 }
 664 EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn);
 665
 666 struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
 667 {
 668         struct crypto_alg *alg;
 669
 670         alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask);
 671         return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg);
 672 }
 673 EXPORT_SYMBOL_GPL(ahash_attr_alg);
 674
 675 bool crypto_hash_alg_has_setkey(struct hash_alg_common *halg)
 676 {
 677         struct crypto_alg *alg = &halg->base;
 678
 679         if (alg->cra_type != &crypto_ahash_type)
 680                 return crypto_shash_alg_has_setkey(__crypto_shash_alg(alg));
 681
 682         return __crypto_ahash_alg(alg)->setkey != NULL;
 683 }
 684 EXPORT_SYMBOL_GPL(crypto_hash_alg_has_setkey);
 685
 686 MODULE_LICENSE("GPL");
 687 MODULE_DESCRIPTION("Asynchronous cryptographic hash type");