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         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 379         struct crypto_alg *alg = tfm->base.__crt_alg;
 380         unsigned int nbytes = req->nbytes;
 381         int ret;
 382
 383         crypto_stats_get(alg);
 384         ret = crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
 385         crypto_stats_ahash_final(nbytes, ret, alg);
 386         return ret;
 387 }
 388 EXPORT_SYMBOL_GPL(crypto_ahash_final);
 389
 390 int crypto_ahash_finup(struct ahash_request *req)
 391 {
 392         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 393         struct crypto_alg *alg = tfm->base.__crt_alg;
 394         unsigned int nbytes = req->nbytes;
 395         int ret;
 396
 397         crypto_stats_get(alg);
 398         ret = crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
 399         crypto_stats_ahash_final(nbytes, ret, alg);
 400         return ret;
 401 }
 402 EXPORT_SYMBOL_GPL(crypto_ahash_finup);
 403
 404 int crypto_ahash_digest(struct ahash_request *req)
 405 {
 406         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 407         struct crypto_alg *alg = tfm->base.__crt_alg;
 408         unsigned int nbytes = req->nbytes;
 409         int ret;
 410
 411         crypto_stats_get(alg);
 412         if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
 413                 ret = -ENOKEY;
 414         else
 415                 ret = crypto_ahash_op(req, tfm->digest);
 416         crypto_stats_ahash_final(nbytes, ret, alg);
 417         return ret;
 418 }
 419 EXPORT_SYMBOL_GPL(crypto_ahash_digest);
 420
 421 static void ahash_def_finup_done2(struct crypto_async_request *req, int err)
 422 {
 423         struct ahash_request *areq = req->data;
 424
 425         if (err == -EINPROGRESS)
 426                 return;
 427
 428         ahash_restore_req(areq, err);
 429
 430         areq->base.complete(&areq->base, err);
 431 }
 432
 433 static int ahash_def_finup_finish1(struct ahash_request *req, int err)
 434 {
 435         if (err)
 436                 goto out;
 437
 438         req->base.complete = ahash_def_finup_done2;
 439
 440         err = crypto_ahash_reqtfm(req)->final(req);
 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(struct crypto_async_request *req, int err)
 450 {
 451         struct ahash_request *areq = req->data;
 452
 453         if (err == -EINPROGRESS) {
 454                 ahash_notify_einprogress(areq);
 455                 return;
 456         }
 457
 458         areq->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
 459
 460         err = ahash_def_finup_finish1(areq, err);
 461         if (areq->priv)
 462                 return;
 463
 464         areq->base.complete(&areq->base, err);
 465 }
 466
 467 static int ahash_def_finup(struct ahash_request *req)
 468 {
 469         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 470         int err;
 471
 472         err = ahash_save_req(req, ahash_def_finup_done1);
 473         if (err)
 474                 return err;
 475
 476         err = tfm->update(req);
 477         if (err == -EINPROGRESS || err == -EBUSY)
 478                 return err;
 479
 480         return ahash_def_finup_finish1(req, err);
 481 }
 482
 483 static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
 484 {
 485         struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
 486         struct ahash_alg *alg = crypto_ahash_alg(hash);
 487
 488         hash->setkey = ahash_nosetkey;
 489
 490         if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
 491                 return crypto_init_shash_ops_async(tfm);
 492
 493         hash->init = alg->init;
 494         hash->update = alg->update;
 495         hash->final = alg->final;
 496         hash->finup = alg->finup ?: ahash_def_finup;
 497         hash->digest = alg->digest;
 498         hash->export = alg->export;
 499         hash->import = alg->import;
 500
 501         if (alg->setkey) {
 502                 hash->setkey = alg->setkey;
 503                 ahash_set_needkey(hash);
 504         }
 505
 506         return 0;
 507 }
 508
 509 static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
 510 {
 511         if (alg->cra_type != &crypto_ahash_type)
 512                 return sizeof(struct crypto_shash *);
 513
 514         return crypto_alg_extsize(alg);
 515 }
 516
 517 #ifdef CONFIG_NET
 518 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 519 {
 520         struct crypto_report_hash rhash;
 521
 522         memset(&rhash, 0, sizeof(rhash));
 523
 524         strscpy(rhash.type, "ahash", sizeof(rhash.type));
 525
 526         rhash.blocksize = alg->cra_blocksize;
 527         rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
 528
 529         return nla_put(skb, CRYPTOCFGA_REPORT_HASH, sizeof(rhash), &rhash);
 530 }
 531 #else
 532 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 533 {
 534         return -ENOSYS;
 535 }
 536 #endif
 537
 538 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 539         __maybe_unused;
 540 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 541 {
 542         seq_printf(m, "type         : ahash\n");
 543         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 544                                              "yes" : "no");
 545         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 546         seq_printf(m, "digestsize   : %u\n",
 547                    __crypto_hash_alg_common(alg)->digestsize);
 548 }
 549
 550 const struct crypto_type crypto_ahash_type = {
 551         .extsize = crypto_ahash_extsize,
 552         .init_tfm = crypto_ahash_init_tfm,
 553 #ifdef CONFIG_PROC_FS
 554         .show = crypto_ahash_show,
 555 #endif
 556         .report = crypto_ahash_report,
 557         .maskclear = ~CRYPTO_ALG_TYPE_MASK,
 558         .maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
 559         .type = CRYPTO_ALG_TYPE_AHASH,
 560         .tfmsize = offsetof(struct crypto_ahash, base),
 561 };
 562 EXPORT_SYMBOL_GPL(crypto_ahash_type);
 563
 564 struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
 565                                         u32 mask)
 566 {
 567         return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
 568 }
 569 EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
 570
 571 int crypto_has_ahash(const char *alg_name, u32 type, u32 mask)
 572 {
 573         return crypto_type_has_alg(alg_name, &crypto_ahash_type, type, mask);
 574 }
 575 EXPORT_SYMBOL_GPL(crypto_has_ahash);
 576
 577 static int ahash_prepare_alg(struct ahash_alg *alg)
 578 {
 579         struct crypto_alg *base = &alg->halg.base;
 580
 581         if (alg->halg.digestsize > HASH_MAX_DIGESTSIZE ||
 582             alg->halg.statesize > HASH_MAX_STATESIZE ||
 583             alg->halg.statesize == 0)
 584                 return -EINVAL;
 585
 586         base->cra_type = &crypto_ahash_type;
 587         base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
 588         base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
 589
 590         return 0;
 591 }
 592
 593 int crypto_register_ahash(struct ahash_alg *alg)
 594 {
 595         struct crypto_alg *base = &alg->halg.base;
 596         int err;
 597
 598         err = ahash_prepare_alg(alg);
 599         if (err)
 600                 return err;
 601
 602         return crypto_register_alg(base);
 603 }
 604 EXPORT_SYMBOL_GPL(crypto_register_ahash);
 605
 606 int crypto_unregister_ahash(struct ahash_alg *alg)
 607 {
 608         return crypto_unregister_alg(&alg->halg.base);
 609 }
 610 EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
 611
 612 int crypto_register_ahashes(struct ahash_alg *algs, int count)
 613 {
 614         int i, ret;
 615
 616         for (i = 0; i < count; i++) {
 617                 ret = crypto_register_ahash(&algs[i]);
 618                 if (ret)
 619                         goto err;
 620         }
 621
 622         return 0;
 623
 624 err:
 625         for (--i; i >= 0; --i)
 626                 crypto_unregister_ahash(&algs[i]);
 627
 628         return ret;
 629 }
 630 EXPORT_SYMBOL_GPL(crypto_register_ahashes);
 631
 632 void crypto_unregister_ahashes(struct ahash_alg *algs, int count)
 633 {
 634         int i;
 635
 636         for (i = count - 1; i >= 0; --i)
 637                 crypto_unregister_ahash(&algs[i]);
 638 }
 639 EXPORT_SYMBOL_GPL(crypto_unregister_ahashes);
 640
 641 int ahash_register_instance(struct crypto_template *tmpl,
 642                             struct ahash_instance *inst)
 643 {
 644         int err;
 645
 646         err = ahash_prepare_alg(&inst->alg);
 647         if (err)
 648                 return err;
 649
 650         return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
 651 }
 652 EXPORT_SYMBOL_GPL(ahash_register_instance);
 653
 654 void ahash_free_instance(struct crypto_instance *inst)
 655 {
 656         crypto_drop_spawn(crypto_instance_ctx(inst));
 657         kfree(ahash_instance(inst));
 658 }
 659 EXPORT_SYMBOL_GPL(ahash_free_instance);
 660
 661 int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
 662                             struct hash_alg_common *alg,
 663                             struct crypto_instance *inst)
 664 {
 665         return crypto_init_spawn2(&spawn->base, &alg->base, inst,
 666                                   &crypto_ahash_type);
 667 }
 668 EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn);
 669
 670 struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
 671 {
 672         struct crypto_alg *alg;
 673
 674         alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask);
 675         return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg);
 676 }
 677 EXPORT_SYMBOL_GPL(ahash_attr_alg);
 678
 679 bool crypto_hash_alg_has_setkey(struct hash_alg_common *halg)
 680 {
 681         struct crypto_alg *alg = &halg->base;
 682
 683         if (alg->cra_type != &crypto_ahash_type)
 684                 return crypto_shash_alg_has_setkey(__crypto_shash_alg(alg));
 685
 686         return __crypto_ahash_alg(alg)->setkey != NULL;
 687 }
 688 EXPORT_SYMBOL_GPL(crypto_hash_alg_has_setkey);
 689
 690 MODULE_LICENSE("GPL");
 691 MODULE_DESCRIPTION("Asynchronous cryptographic hash type");