crypto/shash.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Synchronous Cryptographic Hash operations.
   4  *
   5  * Copyright (c) 2008 Herbert Xu <herbert@gondor.apana.org.au>
   6  */
   7
   8 #include <crypto/scatterwalk.h>
   9 #include <linux/cryptouser.h>
  10 #include <linux/err.h>
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/slab.h>
  14 #include <linux/seq_file.h>
  15 #include <linux/string.h>
  16 #include <net/netlink.h>
  17
  18 #include "hash.h"
  19
  20 #define MAX_SHASH_ALIGNMASK 63
  21
  22 static const struct crypto_type crypto_shash_type;
  23
  24 static inline struct crypto_istat_hash *shash_get_stat(struct shash_alg *alg)
  25 {
  26         return hash_get_stat(&alg->halg);
  27 }
  28
  29 static inline int crypto_shash_errstat(struct shash_alg *alg, int err)
  30 {
  31         return crypto_hash_errstat(&alg->halg, err);
  32 }
  33
  34 int shash_no_setkey(struct crypto_shash *tfm, const u8 *key,
  35                     unsigned int keylen)
  36 {
  37         return -ENOSYS;
  38 }
  39 EXPORT_SYMBOL_GPL(shash_no_setkey);
  40
  41 static int shash_setkey_unaligned(struct crypto_shash *tfm, const u8 *key,
  42                                   unsigned int keylen)
  43 {
  44         struct shash_alg *shash = crypto_shash_alg(tfm);
  45         unsigned long alignmask = crypto_shash_alignmask(tfm);
  46         unsigned long absize;
  47         u8 *buffer, *alignbuffer;
  48         int err;
  49
  50         absize = keylen + (alignmask & ~(crypto_tfm_ctx_alignment() - 1));
  51         buffer = kmalloc(absize, GFP_ATOMIC);
  52         if (!buffer)
  53                 return -ENOMEM;
  54
  55         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
  56         memcpy(alignbuffer, key, keylen);
  57         err = shash->setkey(tfm, alignbuffer, keylen);
  58         kfree_sensitive(buffer);
  59         return err;
  60 }
  61
  62 static void shash_set_needkey(struct crypto_shash *tfm, struct shash_alg *alg)
  63 {
  64         if (crypto_shash_alg_needs_key(alg))
  65                 crypto_shash_set_flags(tfm, CRYPTO_TFM_NEED_KEY);
  66 }
  67
  68 int crypto_shash_setkey(struct crypto_shash *tfm, const u8 *key,
  69                         unsigned int keylen)
  70 {
  71         struct shash_alg *shash = crypto_shash_alg(tfm);
  72         unsigned long alignmask = crypto_shash_alignmask(tfm);
  73         int err;
  74
  75         if ((unsigned long)key & alignmask)
  76                 err = shash_setkey_unaligned(tfm, key, keylen);
  77         else
  78                 err = shash->setkey(tfm, key, keylen);
  79
  80         if (unlikely(err)) {
  81                 shash_set_needkey(tfm, shash);
  82                 return err;
  83         }
  84
  85         crypto_shash_clear_flags(tfm, CRYPTO_TFM_NEED_KEY);
  86         return 0;
  87 }
  88 EXPORT_SYMBOL_GPL(crypto_shash_setkey);
  89
  90 static int shash_update_unaligned(struct shash_desc *desc, const u8 *data,
  91                                   unsigned int len)
  92 {
  93         struct crypto_shash *tfm = desc->tfm;
  94         struct shash_alg *shash = crypto_shash_alg(tfm);
  95         unsigned long alignmask = crypto_shash_alignmask(tfm);
  96         unsigned int unaligned_len = alignmask + 1 -
  97                                      ((unsigned long)data & alignmask);
  98         /*
  99          * We cannot count on __aligned() working for large values:
 100          * https://patchwork.kernel.org/patch/9507697/
 101          */
 102         u8 ubuf[MAX_SHASH_ALIGNMASK * 2];
 103         u8 *buf = PTR_ALIGN(&ubuf[0], alignmask + 1);
 104         int err;
 105
 106         if (WARN_ON(buf + unaligned_len > ubuf + sizeof(ubuf)))
 107                 return -EINVAL;
 108
 109         if (unaligned_len > len)
 110                 unaligned_len = len;
 111
 112         memcpy(buf, data, unaligned_len);
 113         err = shash->update(desc, buf, unaligned_len);
 114         memset(buf, 0, unaligned_len);
 115
 116         return err ?:
 117                shash->update(desc, data + unaligned_len, len - unaligned_len);
 118 }
 119
 120 int crypto_shash_update(struct shash_desc *desc, const u8 *data,
 121                         unsigned int len)
 122 {
 123         struct crypto_shash *tfm = desc->tfm;
 124         struct shash_alg *shash = crypto_shash_alg(tfm);
 125         unsigned long alignmask = crypto_shash_alignmask(tfm);
 126         int err;
 127
 128         if (IS_ENABLED(CONFIG_CRYPTO_STATS))
 129                 atomic64_add(len, &shash_get_stat(shash)->hash_tlen);
 130
 131         if ((unsigned long)data & alignmask)
 132                 err = shash_update_unaligned(desc, data, len);
 133         else
 134                 err = shash->update(desc, data, len);
 135
 136         return crypto_shash_errstat(shash, err);
 137 }
 138 EXPORT_SYMBOL_GPL(crypto_shash_update);
 139
 140 static int shash_final_unaligned(struct shash_desc *desc, u8 *out)
 141 {
 142         struct crypto_shash *tfm = desc->tfm;
 143         unsigned long alignmask = crypto_shash_alignmask(tfm);
 144         struct shash_alg *shash = crypto_shash_alg(tfm);
 145         unsigned int ds = crypto_shash_digestsize(tfm);
 146         /*
 147          * We cannot count on __aligned() working for large values:
 148          * https://patchwork.kernel.org/patch/9507697/
 149          */
 150         u8 ubuf[MAX_SHASH_ALIGNMASK + HASH_MAX_DIGESTSIZE];
 151         u8 *buf = PTR_ALIGN(&ubuf[0], alignmask + 1);
 152         int err;
 153
 154         if (WARN_ON(buf + ds > ubuf + sizeof(ubuf)))
 155                 return -EINVAL;
 156
 157         err = shash->final(desc, buf);
 158         if (err)
 159                 goto out;
 160
 161         memcpy(out, buf, ds);
 162
 163 out:
 164         memset(buf, 0, ds);
 165         return err;
 166 }
 167
 168 int crypto_shash_final(struct shash_desc *desc, u8 *out)
 169 {
 170         struct crypto_shash *tfm = desc->tfm;
 171         struct shash_alg *shash = crypto_shash_alg(tfm);
 172         unsigned long alignmask = crypto_shash_alignmask(tfm);
 173         int err;
 174
 175         if (IS_ENABLED(CONFIG_CRYPTO_STATS))
 176                 atomic64_inc(&shash_get_stat(shash)->hash_cnt);
 177
 178         if ((unsigned long)out & alignmask)
 179                 err = shash_final_unaligned(desc, out);
 180         else
 181                 err = shash->final(desc, out);
 182
 183         return crypto_shash_errstat(shash, err);
 184 }
 185 EXPORT_SYMBOL_GPL(crypto_shash_final);
 186
 187 static int shash_finup_unaligned(struct shash_desc *desc, const u8 *data,
 188                                  unsigned int len, u8 *out)
 189 {
 190         return shash_update_unaligned(desc, data, len) ?:
 191                shash_final_unaligned(desc, out);
 192 }
 193
 194 int crypto_shash_finup(struct shash_desc *desc, const u8 *data,
 195                        unsigned int len, u8 *out)
 196 {
 197         struct crypto_shash *tfm = desc->tfm;
 198         struct shash_alg *shash = crypto_shash_alg(tfm);
 199         unsigned long alignmask = crypto_shash_alignmask(tfm);
 200         int err;
 201
 202         if (IS_ENABLED(CONFIG_CRYPTO_STATS)) {
 203                 struct crypto_istat_hash *istat = shash_get_stat(shash);
 204
 205                 atomic64_inc(&istat->hash_cnt);
 206                 atomic64_add(len, &istat->hash_tlen);
 207         }
 208
 209         if (((unsigned long)data | (unsigned long)out) & alignmask)
 210                 err = shash_finup_unaligned(desc, data, len, out);
 211         else
 212                 err = shash->finup(desc, data, len, out);
 213
 214
 215         return crypto_shash_errstat(shash, err);
 216 }
 217 EXPORT_SYMBOL_GPL(crypto_shash_finup);
 218
 219 static int shash_digest_unaligned(struct shash_desc *desc, const u8 *data,
 220                                   unsigned int len, u8 *out)
 221 {
 222         return crypto_shash_init(desc) ?:
 223                shash_update_unaligned(desc, data, len) ?:
 224                shash_final_unaligned(desc, out);
 225 }
 226
 227 int crypto_shash_digest(struct shash_desc *desc, const u8 *data,
 228                         unsigned int len, u8 *out)
 229 {
 230         struct crypto_shash *tfm = desc->tfm;
 231         struct shash_alg *shash = crypto_shash_alg(tfm);
 232         unsigned long alignmask = crypto_shash_alignmask(tfm);
 233         int err;
 234
 235         if (IS_ENABLED(CONFIG_CRYPTO_STATS)) {
 236                 struct crypto_istat_hash *istat = shash_get_stat(shash);
 237
 238                 atomic64_inc(&istat->hash_cnt);
 239                 atomic64_add(len, &istat->hash_tlen);
 240         }
 241
 242         if (crypto_shash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
 243                 err = -ENOKEY;
 244         else if (((unsigned long)data | (unsigned long)out) & alignmask)
 245                 err = shash_digest_unaligned(desc, data, len, out);
 246         else
 247                 err = shash->digest(desc, data, len, out);
 248
 249         return crypto_shash_errstat(shash, err);
 250 }
 251 EXPORT_SYMBOL_GPL(crypto_shash_digest);
 252
 253 int crypto_shash_tfm_digest(struct crypto_shash *tfm, const u8 *data,
 254                             unsigned int len, u8 *out)
 255 {
 256         SHASH_DESC_ON_STACK(desc, tfm);
 257         int err;
 258
 259         desc->tfm = tfm;
 260
 261         err = crypto_shash_digest(desc, data, len, out);
 262
 263         shash_desc_zero(desc);
 264
 265         return err;
 266 }
 267 EXPORT_SYMBOL_GPL(crypto_shash_tfm_digest);
 268
 269 static int shash_default_export(struct shash_desc *desc, void *out)
 270 {
 271         memcpy(out, shash_desc_ctx(desc), crypto_shash_descsize(desc->tfm));
 272         return 0;
 273 }
 274
 275 static int shash_default_import(struct shash_desc *desc, const void *in)
 276 {
 277         memcpy(shash_desc_ctx(desc), in, crypto_shash_descsize(desc->tfm));
 278         return 0;
 279 }
 280
 281 static int shash_async_setkey(struct crypto_ahash *tfm, const u8 *key,
 282                               unsigned int keylen)
 283 {
 284         struct crypto_shash **ctx = crypto_ahash_ctx(tfm);
 285
 286         return crypto_shash_setkey(*ctx, key, keylen);
 287 }
 288
 289 static int shash_async_init(struct ahash_request *req)
 290 {
 291         struct crypto_shash **ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
 292         struct shash_desc *desc = ahash_request_ctx(req);
 293
 294         desc->tfm = *ctx;
 295
 296         return crypto_shash_init(desc);
 297 }
 298
 299 int shash_ahash_update(struct ahash_request *req, struct shash_desc *desc)
 300 {
 301         struct crypto_hash_walk walk;
 302         int nbytes;
 303
 304         for (nbytes = crypto_hash_walk_first(req, &walk); nbytes > 0;
 305              nbytes = crypto_hash_walk_done(&walk, nbytes))
 306                 nbytes = crypto_shash_update(desc, walk.data, nbytes);
 307
 308         return nbytes;
 309 }
 310 EXPORT_SYMBOL_GPL(shash_ahash_update);
 311
 312 static int shash_async_update(struct ahash_request *req)
 313 {
 314         return shash_ahash_update(req, ahash_request_ctx(req));
 315 }
 316
 317 static int shash_async_final(struct ahash_request *req)
 318 {
 319         return crypto_shash_final(ahash_request_ctx(req), req->result);
 320 }
 321
 322 int shash_ahash_finup(struct ahash_request *req, struct shash_desc *desc)
 323 {
 324         struct crypto_hash_walk walk;
 325         int nbytes;
 326
 327         nbytes = crypto_hash_walk_first(req, &walk);
 328         if (!nbytes)
 329                 return crypto_shash_final(desc, req->result);
 330
 331         do {
 332                 nbytes = crypto_hash_walk_last(&walk) ?
 333                          crypto_shash_finup(desc, walk.data, nbytes,
 334                                             req->result) :
 335                          crypto_shash_update(desc, walk.data, nbytes);
 336                 nbytes = crypto_hash_walk_done(&walk, nbytes);
 337         } while (nbytes > 0);
 338
 339         return nbytes;
 340 }
 341 EXPORT_SYMBOL_GPL(shash_ahash_finup);
 342
 343 static int shash_async_finup(struct ahash_request *req)
 344 {
 345         struct crypto_shash **ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
 346         struct shash_desc *desc = ahash_request_ctx(req);
 347
 348         desc->tfm = *ctx;
 349
 350         return shash_ahash_finup(req, desc);
 351 }
 352
 353 int shash_ahash_digest(struct ahash_request *req, struct shash_desc *desc)
 354 {
 355         unsigned int nbytes = req->nbytes;
 356         struct scatterlist *sg;
 357         unsigned int offset;
 358         int err;
 359
 360         if (nbytes &&
 361             (sg = req->src, offset = sg->offset,
 362              nbytes <= min(sg->length, ((unsigned int)(PAGE_SIZE)) - offset))) {
 363                 void *data;
 364
 365                 data = kmap_local_page(sg_page(sg));
 366                 err = crypto_shash_digest(desc, data + offset, nbytes,
 367                                           req->result);
 368                 kunmap_local(data);
 369         } else
 370                 err = crypto_shash_init(desc) ?:
 371                       shash_ahash_finup(req, desc);
 372
 373         return err;
 374 }
 375 EXPORT_SYMBOL_GPL(shash_ahash_digest);
 376
 377 static int shash_async_digest(struct ahash_request *req)
 378 {
 379         struct crypto_shash **ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
 380         struct shash_desc *desc = ahash_request_ctx(req);
 381
 382         desc->tfm = *ctx;
 383
 384         return shash_ahash_digest(req, desc);
 385 }
 386
 387 static int shash_async_export(struct ahash_request *req, void *out)
 388 {
 389         return crypto_shash_export(ahash_request_ctx(req), out);
 390 }
 391
 392 static int shash_async_import(struct ahash_request *req, const void *in)
 393 {
 394         struct crypto_shash **ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
 395         struct shash_desc *desc = ahash_request_ctx(req);
 396
 397         desc->tfm = *ctx;
 398
 399         return crypto_shash_import(desc, in);
 400 }
 401
 402 static void crypto_exit_shash_ops_async(struct crypto_tfm *tfm)
 403 {
 404         struct crypto_shash **ctx = crypto_tfm_ctx(tfm);
 405
 406         crypto_free_shash(*ctx);
 407 }
 408
 409 int crypto_init_shash_ops_async(struct crypto_tfm *tfm)
 410 {
 411         struct crypto_alg *calg = tfm->__crt_alg;
 412         struct shash_alg *alg = __crypto_shash_alg(calg);
 413         struct crypto_ahash *crt = __crypto_ahash_cast(tfm);
 414         struct crypto_shash **ctx = crypto_tfm_ctx(tfm);
 415         struct crypto_shash *shash;
 416
 417         if (!crypto_mod_get(calg))
 418                 return -EAGAIN;
 419
 420         shash = crypto_create_tfm(calg, &crypto_shash_type);
 421         if (IS_ERR(shash)) {
 422                 crypto_mod_put(calg);
 423                 return PTR_ERR(shash);
 424         }
 425
 426         *ctx = shash;
 427         tfm->exit = crypto_exit_shash_ops_async;
 428
 429         crt->init = shash_async_init;
 430         crt->update = shash_async_update;
 431         crt->final = shash_async_final;
 432         crt->finup = shash_async_finup;
 433         crt->digest = shash_async_digest;
 434         if (crypto_shash_alg_has_setkey(alg))
 435                 crt->setkey = shash_async_setkey;
 436
 437         crypto_ahash_set_flags(crt, crypto_shash_get_flags(shash) &
 438                                     CRYPTO_TFM_NEED_KEY);
 439
 440         crt->export = shash_async_export;
 441         crt->import = shash_async_import;
 442
 443         crt->reqsize = sizeof(struct shash_desc) + crypto_shash_descsize(shash);
 444
 445         return 0;
 446 }
 447
 448 static void crypto_shash_exit_tfm(struct crypto_tfm *tfm)
 449 {
 450         struct crypto_shash *hash = __crypto_shash_cast(tfm);
 451         struct shash_alg *alg = crypto_shash_alg(hash);
 452
 453         alg->exit_tfm(hash);
 454 }
 455
 456 static int crypto_shash_init_tfm(struct crypto_tfm *tfm)
 457 {
 458         struct crypto_shash *hash = __crypto_shash_cast(tfm);
 459         struct shash_alg *alg = crypto_shash_alg(hash);
 460         int err;
 461
 462         hash->descsize = alg->descsize;
 463
 464         shash_set_needkey(hash, alg);
 465
 466         if (alg->exit_tfm)
 467                 tfm->exit = crypto_shash_exit_tfm;
 468
 469         if (!alg->init_tfm)
 470                 return 0;
 471
 472         err = alg->init_tfm(hash);
 473         if (err)
 474                 return err;
 475
 476         /* ->init_tfm() may have increased the descsize. */
 477         if (WARN_ON_ONCE(hash->descsize > HASH_MAX_DESCSIZE)) {
 478                 if (alg->exit_tfm)
 479                         alg->exit_tfm(hash);
 480                 return -EINVAL;
 481         }
 482
 483         return 0;
 484 }
 485
 486 static void crypto_shash_free_instance(struct crypto_instance *inst)
 487 {
 488         struct shash_instance *shash = shash_instance(inst);
 489
 490         shash->free(shash);
 491 }
 492
 493 static int __maybe_unused crypto_shash_report(
 494         struct sk_buff *skb, struct crypto_alg *alg)
 495 {
 496         struct crypto_report_hash rhash;
 497         struct shash_alg *salg = __crypto_shash_alg(alg);
 498
 499         memset(&rhash, 0, sizeof(rhash));
 500
 501         strscpy(rhash.type, "shash", sizeof(rhash.type));
 502
 503         rhash.blocksize = alg->cra_blocksize;
 504         rhash.digestsize = salg->digestsize;
 505
 506         return nla_put(skb, CRYPTOCFGA_REPORT_HASH, sizeof(rhash), &rhash);
 507 }
 508
 509 static void crypto_shash_show(struct seq_file *m, struct crypto_alg *alg)
 510         __maybe_unused;
 511 static void crypto_shash_show(struct seq_file *m, struct crypto_alg *alg)
 512 {
 513         struct shash_alg *salg = __crypto_shash_alg(alg);
 514
 515         seq_printf(m, "type         : shash\n");
 516         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 517         seq_printf(m, "digestsize   : %u\n", salg->digestsize);
 518 }
 519
 520 static int __maybe_unused crypto_shash_report_stat(
 521         struct sk_buff *skb, struct crypto_alg *alg)
 522 {
 523         return crypto_hash_report_stat(skb, alg, "shash");
 524 }
 525
 526 static const struct crypto_type crypto_shash_type = {
 527         .extsize = crypto_alg_extsize,
 528         .init_tfm = crypto_shash_init_tfm,
 529         .free = crypto_shash_free_instance,
 530 #ifdef CONFIG_PROC_FS
 531         .show = crypto_shash_show,
 532 #endif
 533 #ifdef CONFIG_CRYPTO_USER
 534         .report = crypto_shash_report,
 535 #endif
 536 #ifdef CONFIG_CRYPTO_STATS
 537         .report_stat = crypto_shash_report_stat,
 538 #endif
 539         .maskclear = ~CRYPTO_ALG_TYPE_MASK,
 540         .maskset = CRYPTO_ALG_TYPE_MASK,
 541         .type = CRYPTO_ALG_TYPE_SHASH,
 542         .tfmsize = offsetof(struct crypto_shash, base),
 543 };
 544
 545 int crypto_grab_shash(struct crypto_shash_spawn *spawn,
 546                       struct crypto_instance *inst,
 547                       const char *name, u32 type, u32 mask)
 548 {
 549         spawn->base.frontend = &crypto_shash_type;
 550         return crypto_grab_spawn(&spawn->base, inst, name, type, mask);
 551 }
 552 EXPORT_SYMBOL_GPL(crypto_grab_shash);
 553
 554 struct crypto_shash *crypto_alloc_shash(const char *alg_name, u32 type,
 555                                         u32 mask)
 556 {
 557         return crypto_alloc_tfm(alg_name, &crypto_shash_type, type, mask);
 558 }
 559 EXPORT_SYMBOL_GPL(crypto_alloc_shash);
 560
 561 int crypto_has_shash(const char *alg_name, u32 type, u32 mask)
 562 {
 563         return crypto_type_has_alg(alg_name, &crypto_shash_type, type, mask);
 564 }
 565 EXPORT_SYMBOL_GPL(crypto_has_shash);
 566
 567 int hash_prepare_alg(struct hash_alg_common *alg)
 568 {
 569         struct crypto_istat_hash *istat = hash_get_stat(alg);
 570         struct crypto_alg *base = &alg->base;
 571
 572         if (alg->digestsize > HASH_MAX_DIGESTSIZE)
 573                 return -EINVAL;
 574
 575         base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
 576
 577         if (IS_ENABLED(CONFIG_CRYPTO_STATS))
 578                 memset(istat, 0, sizeof(*istat));
 579
 580         return 0;
 581 }
 582
 583 static int shash_prepare_alg(struct shash_alg *alg)
 584 {
 585         struct crypto_alg *base = &alg->halg.base;
 586         int err;
 587
 588         if (alg->descsize > HASH_MAX_DESCSIZE)
 589                 return -EINVAL;
 590
 591         if (base->cra_alignmask > MAX_SHASH_ALIGNMASK)
 592                 return -EINVAL;
 593
 594         if ((alg->export && !alg->import) || (alg->import && !alg->export))
 595                 return -EINVAL;
 596
 597         err = hash_prepare_alg(&alg->halg);
 598         if (err)
 599                 return err;
 600
 601         base->cra_type = &crypto_shash_type;
 602         base->cra_flags |= CRYPTO_ALG_TYPE_SHASH;
 603
 604         if (!alg->finup)
 605                 alg->finup = shash_finup_unaligned;
 606         if (!alg->digest)
 607                 alg->digest = shash_digest_unaligned;
 608         if (!alg->export) {
 609                 alg->export = shash_default_export;
 610                 alg->import = shash_default_import;
 611                 alg->halg.statesize = alg->descsize;
 612         }
 613         if (!alg->setkey)
 614                 alg->setkey = shash_no_setkey;
 615
 616         return 0;
 617 }
 618
 619 int crypto_register_shash(struct shash_alg *alg)
 620 {
 621         struct crypto_alg *base = &alg->base;
 622         int err;
 623
 624         err = shash_prepare_alg(alg);
 625         if (err)
 626                 return err;
 627
 628         return crypto_register_alg(base);
 629 }
 630 EXPORT_SYMBOL_GPL(crypto_register_shash);
 631
 632 void crypto_unregister_shash(struct shash_alg *alg)
 633 {
 634         crypto_unregister_alg(&alg->base);
 635 }
 636 EXPORT_SYMBOL_GPL(crypto_unregister_shash);
 637
 638 int crypto_register_shashes(struct shash_alg *algs, int count)
 639 {
 640         int i, ret;
 641
 642         for (i = 0; i < count; i++) {
 643                 ret = crypto_register_shash(&algs[i]);
 644                 if (ret)
 645                         goto err;
 646         }
 647
 648         return 0;
 649
 650 err:
 651         for (--i; i >= 0; --i)
 652                 crypto_unregister_shash(&algs[i]);
 653
 654         return ret;
 655 }
 656 EXPORT_SYMBOL_GPL(crypto_register_shashes);
 657
 658 void crypto_unregister_shashes(struct shash_alg *algs, int count)
 659 {
 660         int i;
 661
 662         for (i = count - 1; i >= 0; --i)
 663                 crypto_unregister_shash(&algs[i]);
 664 }
 665 EXPORT_SYMBOL_GPL(crypto_unregister_shashes);
 666
 667 int shash_register_instance(struct crypto_template *tmpl,
 668                             struct shash_instance *inst)
 669 {
 670         int err;
 671
 672         if (WARN_ON(!inst->free))
 673                 return -EINVAL;
 674
 675         err = shash_prepare_alg(&inst->alg);
 676         if (err)
 677                 return err;
 678
 679         return crypto_register_instance(tmpl, shash_crypto_instance(inst));
 680 }
 681 EXPORT_SYMBOL_GPL(shash_register_instance);
 682
 683 void shash_free_singlespawn_instance(struct shash_instance *inst)
 684 {
 685         crypto_drop_spawn(shash_instance_ctx(inst));
 686         kfree(inst);
 687 }
 688 EXPORT_SYMBOL_GPL(shash_free_singlespawn_instance);
 689
 690 MODULE_LICENSE("GPL");
 691 MODULE_DESCRIPTION("Synchronous cryptographic hash type");