crypto/ahash.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Asynchronous Cryptographic Hash operations.
   4  *
   5  * This is the asynchronous version of hash.c with notification of
   6  * completion via a callback.
   7  *
   8  * Copyright (c) 2008 Loc Ho <lho@amcc.com>
   9  */
  10
  11 #include <crypto/internal/hash.h>
  12 #include <crypto/scatterwalk.h>
  13 #include <linux/err.h>
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/sched.h>
  17 #include <linux/slab.h>
  18 #include <linux/seq_file.h>
  19 #include <linux/cryptouser.h>
  20 #include <linux/compiler.h>
  21 #include <net/netlink.h>
  22
  23 #include "internal.h"
  24
  25 static const struct crypto_type crypto_ahash_type;
  26
  27 struct ahash_request_priv {
  28         crypto_completion_t complete;
  29         void *data;
  30         u8 *result;
  31         u32 flags;
  32         void *ubuf[] CRYPTO_MINALIGN_ATTR;
  33 };
  34
  35 static inline struct ahash_alg *crypto_ahash_alg(struct crypto_ahash *hash)
  36 {
  37         return container_of(crypto_hash_alg_common(hash), struct ahash_alg,
  38                             halg);
  39 }
  40
  41 static int hash_walk_next(struct crypto_hash_walk *walk)
  42 {
  43         unsigned int alignmask = walk->alignmask;
  44         unsigned int offset = walk->offset;
  45         unsigned int nbytes = min(walk->entrylen,
  46                                   ((unsigned int)(PAGE_SIZE)) - offset);
  47
  48         walk->data = kmap_atomic(walk->pg);
  49         walk->data += offset;
  50
  51         if (offset & alignmask) {
  52                 unsigned int unaligned = alignmask + 1 - (offset & alignmask);
  53
  54                 if (nbytes > unaligned)
  55                         nbytes = unaligned;
  56         }
  57
  58         walk->entrylen -= nbytes;
  59         return nbytes;
  60 }
  61
  62 static int hash_walk_new_entry(struct crypto_hash_walk *walk)
  63 {
  64         struct scatterlist *sg;
  65
  66         sg = walk->sg;
  67         walk->offset = sg->offset;
  68         walk->pg = sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
  69         walk->offset = offset_in_page(walk->offset);
  70         walk->entrylen = sg->length;
  71
  72         if (walk->entrylen > walk->total)
  73                 walk->entrylen = walk->total;
  74         walk->total -= walk->entrylen;
  75
  76         return hash_walk_next(walk);
  77 }
  78
  79 int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
  80 {
  81         unsigned int alignmask = walk->alignmask;
  82
  83         walk->data -= walk->offset;
  84
  85         if (walk->entrylen && (walk->offset & alignmask) && !err) {
  86                 unsigned int nbytes;
  87
  88                 walk->offset = ALIGN(walk->offset, alignmask + 1);
  89                 nbytes = min(walk->entrylen,
  90                              (unsigned int)(PAGE_SIZE - walk->offset));
  91                 if (nbytes) {
  92                         walk->entrylen -= nbytes;
  93                         walk->data += walk->offset;
  94                         return nbytes;
  95                 }
  96         }
  97
  98         kunmap_atomic(walk->data);
  99         crypto_yield(walk->flags);
 100
 101         if (err)
 102                 return err;
 103
 104         if (walk->entrylen) {
 105                 walk->offset = 0;
 106                 walk->pg++;
 107                 return hash_walk_next(walk);
 108         }
 109
 110         if (!walk->total)
 111                 return 0;
 112
 113         walk->sg = sg_next(walk->sg);
 114
 115         return hash_walk_new_entry(walk);
 116 }
 117 EXPORT_SYMBOL_GPL(crypto_hash_walk_done);
 118
 119 int crypto_hash_walk_first(struct ahash_request *req,
 120                            struct crypto_hash_walk *walk)
 121 {
 122         walk->total = req->nbytes;
 123
 124         if (!walk->total) {
 125                 walk->entrylen = 0;
 126                 return 0;
 127         }
 128
 129         walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
 130         walk->sg = req->src;
 131         walk->flags = req->base.flags;
 132
 133         return hash_walk_new_entry(walk);
 134 }
 135 EXPORT_SYMBOL_GPL(crypto_hash_walk_first);
 136
 137 static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,
 138                                 unsigned int keylen)
 139 {
 140         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 141         int ret;
 142         u8 *buffer, *alignbuffer;
 143         unsigned long absize;
 144
 145         absize = keylen + alignmask;
 146         buffer = kmalloc(absize, GFP_KERNEL);
 147         if (!buffer)
 148                 return -ENOMEM;
 149
 150         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 151         memcpy(alignbuffer, key, keylen);
 152         ret = tfm->setkey(tfm, alignbuffer, keylen);
 153         kfree_sensitive(buffer);
 154         return ret;
 155 }
 156
 157 static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
 158                           unsigned int keylen)
 159 {
 160         return -ENOSYS;
 161 }
 162
 163 static void ahash_set_needkey(struct crypto_ahash *tfm)
 164 {
 165         const struct hash_alg_common *alg = crypto_hash_alg_common(tfm);
 166
 167         if (tfm->setkey != ahash_nosetkey &&
 168             !(alg->base.cra_flags & CRYPTO_ALG_OPTIONAL_KEY))
 169                 crypto_ahash_set_flags(tfm, CRYPTO_TFM_NEED_KEY);
 170 }
 171
 172 int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
 173                         unsigned int keylen)
 174 {
 175         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 176         int err;
 177
 178         if ((unsigned long)key & alignmask)
 179                 err = ahash_setkey_unaligned(tfm, key, keylen);
 180         else
 181                 err = tfm->setkey(tfm, key, keylen);
 182
 183         if (unlikely(err)) {
 184                 ahash_set_needkey(tfm);
 185                 return err;
 186         }
 187
 188         crypto_ahash_clear_flags(tfm, CRYPTO_TFM_NEED_KEY);
 189         return 0;
 190 }
 191 EXPORT_SYMBOL_GPL(crypto_ahash_setkey);
 192
 193 static inline unsigned int ahash_align_buffer_size(unsigned len,
 194                                                    unsigned long mask)
 195 {
 196         return len + (mask & ~(crypto_tfm_ctx_alignment() - 1));
 197 }
 198
 199 static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt)
 200 {
 201         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 202         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 203         unsigned int ds = crypto_ahash_digestsize(tfm);
 204         struct ahash_request_priv *priv;
 205
 206         priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
 207                        (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
 208                        GFP_KERNEL : GFP_ATOMIC);
 209         if (!priv)
 210                 return -ENOMEM;
 211
 212         /*
 213          * WARNING: Voodoo programming below!
 214          *
 215          * The code below is obscure and hard to understand, thus explanation
 216          * is necessary. See include/crypto/hash.h and include/linux/crypto.h
 217          * to understand the layout of structures used here!
 218          *
 219          * The code here will replace portions of the ORIGINAL request with
 220          * pointers to new code and buffers so the hashing operation can store
 221          * the result in aligned buffer. We will call the modified request
 222          * an ADJUSTED request.
 223          *
 224          * The newly mangled request will look as such:
 225          *
 226          * req {
 227          *   .result        = ADJUSTED[new aligned buffer]
 228          *   .base.complete = ADJUSTED[pointer to completion function]
 229          *   .base.data     = ADJUSTED[*req (pointer to self)]
 230          *   .priv          = ADJUSTED[new priv] {
 231          *           .result   = ORIGINAL(result)
 232          *           .complete = ORIGINAL(base.complete)
 233          *           .data     = ORIGINAL(base.data)
 234          *   }
 235          */
 236
 237         priv->result = req->result;
 238         priv->complete = req->base.complete;
 239         priv->data = req->base.data;
 240         priv->flags = req->base.flags;
 241
 242         /*
 243          * WARNING: We do not backup req->priv here! The req->priv
 244          *          is for internal use of the Crypto API and the
 245          *          user must _NOT_ _EVER_ depend on it's content!
 246          */
 247
 248         req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
 249         req->base.complete = cplt;
 250         req->base.data = req;
 251         req->priv = priv;
 252
 253         return 0;
 254 }
 255
 256 static void ahash_restore_req(struct ahash_request *req, int err)
 257 {
 258         struct ahash_request_priv *priv = req->priv;
 259
 260         if (!err)
 261                 memcpy(priv->result, req->result,
 262                        crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
 263
 264         /* Restore the original crypto request. */
 265         req->result = priv->result;
 266
 267         ahash_request_set_callback(req, priv->flags,
 268                                    priv->complete, priv->data);
 269         req->priv = NULL;
 270
 271         /* Free the req->priv.priv from the ADJUSTED request. */
 272         kfree_sensitive(priv);
 273 }
 274
 275 static void ahash_notify_einprogress(struct ahash_request *req)
 276 {
 277         struct ahash_request_priv *priv = req->priv;
 278         struct crypto_async_request oreq;
 279
 280         oreq.data = priv->data;
 281
 282         priv->complete(&oreq, -EINPROGRESS);
 283 }
 284
 285 static void ahash_op_unaligned_done(struct crypto_async_request *req, int err)
 286 {
 287         struct ahash_request *areq = req->data;
 288
 289         if (err == -EINPROGRESS) {
 290                 ahash_notify_einprogress(areq);
 291                 return;
 292         }
 293
 294         /*
 295          * Restore the original request, see ahash_op_unaligned() for what
 296          * goes where.
 297          *
 298          * The "struct ahash_request *req" here is in fact the "req.base"
 299          * from the ADJUSTED request from ahash_op_unaligned(), thus as it
 300          * is a pointer to self, it is also the ADJUSTED "req" .
 301          */
 302
 303         /* First copy req->result into req->priv.result */
 304         ahash_restore_req(areq, err);
 305
 306         /* Complete the ORIGINAL request. */
 307         areq->base.complete(&areq->base, err);
 308 }
 309
 310 static int ahash_op_unaligned(struct ahash_request *req,
 311                               int (*op)(struct ahash_request *))
 312 {
 313         int err;
 314
 315         err = ahash_save_req(req, ahash_op_unaligned_done);
 316         if (err)
 317                 return err;
 318
 319         err = op(req);
 320         if (err == -EINPROGRESS || err == -EBUSY)
 321                 return err;
 322
 323         ahash_restore_req(req, err);
 324
 325         return err;
 326 }
 327
 328 static int crypto_ahash_op(struct ahash_request *req,
 329                            int (*op)(struct ahash_request *))
 330 {
 331         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 332         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 333
 334         if ((unsigned long)req->result & alignmask)
 335                 return ahash_op_unaligned(req, op);
 336
 337         return op(req);
 338 }
 339
 340 int crypto_ahash_final(struct ahash_request *req)
 341 {
 342         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 343         struct crypto_alg *alg = tfm->base.__crt_alg;
 344         unsigned int nbytes = req->nbytes;
 345         int ret;
 346
 347         crypto_stats_get(alg);
 348         ret = crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
 349         crypto_stats_ahash_final(nbytes, ret, alg);
 350         return ret;
 351 }
 352 EXPORT_SYMBOL_GPL(crypto_ahash_final);
 353
 354 int crypto_ahash_finup(struct ahash_request *req)
 355 {
 356         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 357         struct crypto_alg *alg = tfm->base.__crt_alg;
 358         unsigned int nbytes = req->nbytes;
 359         int ret;
 360
 361         crypto_stats_get(alg);
 362         ret = crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
 363         crypto_stats_ahash_final(nbytes, ret, alg);
 364         return ret;
 365 }
 366 EXPORT_SYMBOL_GPL(crypto_ahash_finup);
 367
 368 int crypto_ahash_digest(struct ahash_request *req)
 369 {
 370         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 371         struct crypto_alg *alg = tfm->base.__crt_alg;
 372         unsigned int nbytes = req->nbytes;
 373         int ret;
 374
 375         crypto_stats_get(alg);
 376         if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
 377                 ret = -ENOKEY;
 378         else
 379                 ret = crypto_ahash_op(req, tfm->digest);
 380         crypto_stats_ahash_final(nbytes, ret, alg);
 381         return ret;
 382 }
 383 EXPORT_SYMBOL_GPL(crypto_ahash_digest);
 384
 385 static void ahash_def_finup_done2(struct crypto_async_request *req, int err)
 386 {
 387         struct ahash_request *areq = req->data;
 388
 389         if (err == -EINPROGRESS)
 390                 return;
 391
 392         ahash_restore_req(areq, err);
 393
 394         areq->base.complete(&areq->base, err);
 395 }
 396
 397 static int ahash_def_finup_finish1(struct ahash_request *req, int err)
 398 {
 399         if (err)
 400                 goto out;
 401
 402         req->base.complete = ahash_def_finup_done2;
 403
 404         err = crypto_ahash_reqtfm(req)->final(req);
 405         if (err == -EINPROGRESS || err == -EBUSY)
 406                 return err;
 407
 408 out:
 409         ahash_restore_req(req, err);
 410         return err;
 411 }
 412
 413 static void ahash_def_finup_done1(struct crypto_async_request *req, int err)
 414 {
 415         struct ahash_request *areq = req->data;
 416
 417         if (err == -EINPROGRESS) {
 418                 ahash_notify_einprogress(areq);
 419                 return;
 420         }
 421
 422         areq->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
 423
 424         err = ahash_def_finup_finish1(areq, err);
 425         if (areq->priv)
 426                 return;
 427
 428         areq->base.complete(&areq->base, err);
 429 }
 430
 431 static int ahash_def_finup(struct ahash_request *req)
 432 {
 433         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 434         int err;
 435
 436         err = ahash_save_req(req, ahash_def_finup_done1);
 437         if (err)
 438                 return err;
 439
 440         err = tfm->update(req);
 441         if (err == -EINPROGRESS || err == -EBUSY)
 442                 return err;
 443
 444         return ahash_def_finup_finish1(req, err);
 445 }
 446
 447 static void crypto_ahash_exit_tfm(struct crypto_tfm *tfm)
 448 {
 449         struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
 450         struct ahash_alg *alg = crypto_ahash_alg(hash);
 451
 452         alg->exit_tfm(hash);
 453 }
 454
 455 static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
 456 {
 457         struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
 458         struct ahash_alg *alg = crypto_ahash_alg(hash);
 459
 460         hash->setkey = ahash_nosetkey;
 461
 462         if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
 463                 return crypto_init_shash_ops_async(tfm);
 464
 465         hash->init = alg->init;
 466         hash->update = alg->update;
 467         hash->final = alg->final;
 468         hash->finup = alg->finup ?: ahash_def_finup;
 469         hash->digest = alg->digest;
 470         hash->export = alg->export;
 471         hash->import = alg->import;
 472
 473         if (alg->setkey) {
 474                 hash->setkey = alg->setkey;
 475                 ahash_set_needkey(hash);
 476         }
 477
 478         if (alg->exit_tfm)
 479                 tfm->exit = crypto_ahash_exit_tfm;
 480
 481         return alg->init_tfm ? alg->init_tfm(hash) : 0;
 482 }
 483
 484 static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
 485 {
 486         if (alg->cra_type != &crypto_ahash_type)
 487                 return sizeof(struct crypto_shash *);
 488
 489         return crypto_alg_extsize(alg);
 490 }
 491
 492 static void crypto_ahash_free_instance(struct crypto_instance *inst)
 493 {
 494         struct ahash_instance *ahash = ahash_instance(inst);
 495
 496         ahash->free(ahash);
 497 }
 498
 499 #ifdef CONFIG_NET
 500 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 501 {
 502         struct crypto_report_hash rhash;
 503
 504         memset(&rhash, 0, sizeof(rhash));
 505
 506         strscpy(rhash.type, "ahash", sizeof(rhash.type));
 507
 508         rhash.blocksize = alg->cra_blocksize;
 509         rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
 510
 511         return nla_put(skb, CRYPTOCFGA_REPORT_HASH, sizeof(rhash), &rhash);
 512 }
 513 #else
 514 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 515 {
 516         return -ENOSYS;
 517 }
 518 #endif
 519
 520 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 521         __maybe_unused;
 522 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 523 {
 524         seq_printf(m, "type         : ahash\n");
 525         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 526                                              "yes" : "no");
 527         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 528         seq_printf(m, "digestsize   : %u\n",
 529                    __crypto_hash_alg_common(alg)->digestsize);
 530 }
 531
 532 static const struct crypto_type crypto_ahash_type = {
 533         .extsize = crypto_ahash_extsize,
 534         .init_tfm = crypto_ahash_init_tfm,
 535         .free = crypto_ahash_free_instance,
 536 #ifdef CONFIG_PROC_FS
 537         .show = crypto_ahash_show,
 538 #endif
 539         .report = crypto_ahash_report,
 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 int ahash_prepare_alg(struct ahash_alg *alg)
 569 {
 570         struct crypto_alg *base = &alg->halg.base;
 571
 572         if (alg->halg.digestsize > HASH_MAX_DIGESTSIZE ||
 573             alg->halg.statesize > HASH_MAX_STATESIZE ||
 574             alg->halg.statesize == 0)
 575                 return -EINVAL;
 576
 577         base->cra_type = &crypto_ahash_type;
 578         base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
 579         base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
 580
 581         return 0;
 582 }
 583
 584 int crypto_register_ahash(struct ahash_alg *alg)
 585 {
 586         struct crypto_alg *base = &alg->halg.base;
 587         int err;
 588
 589         err = ahash_prepare_alg(alg);
 590         if (err)
 591                 return err;
 592
 593         return crypto_register_alg(base);
 594 }
 595 EXPORT_SYMBOL_GPL(crypto_register_ahash);
 596
 597 void crypto_unregister_ahash(struct ahash_alg *alg)
 598 {
 599         crypto_unregister_alg(&alg->halg.base);
 600 }
 601 EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
 602
 603 int crypto_register_ahashes(struct ahash_alg *algs, int count)
 604 {
 605         int i, ret;
 606
 607         for (i = 0; i < count; i++) {
 608                 ret = crypto_register_ahash(&algs[i]);
 609                 if (ret)
 610                         goto err;
 611         }
 612
 613         return 0;
 614
 615 err:
 616         for (--i; i >= 0; --i)
 617                 crypto_unregister_ahash(&algs[i]);
 618
 619         return ret;
 620 }
 621 EXPORT_SYMBOL_GPL(crypto_register_ahashes);
 622
 623 void crypto_unregister_ahashes(struct ahash_alg *algs, int count)
 624 {
 625         int i;
 626
 627         for (i = count - 1; i >= 0; --i)
 628                 crypto_unregister_ahash(&algs[i]);
 629 }
 630 EXPORT_SYMBOL_GPL(crypto_unregister_ahashes);
 631
 632 int ahash_register_instance(struct crypto_template *tmpl,
 633                             struct ahash_instance *inst)
 634 {
 635         int err;
 636
 637         if (WARN_ON(!inst->free))
 638                 return -EINVAL;
 639
 640         err = ahash_prepare_alg(&inst->alg);
 641         if (err)
 642                 return err;
 643
 644         return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
 645 }
 646 EXPORT_SYMBOL_GPL(ahash_register_instance);
 647
 648 bool crypto_hash_alg_has_setkey(struct hash_alg_common *halg)
 649 {
 650         struct crypto_alg *alg = &halg->base;
 651
 652         if (alg->cra_type != &crypto_ahash_type)
 653                 return crypto_shash_alg_has_setkey(__crypto_shash_alg(alg));
 654
 655         return __crypto_ahash_alg(alg)->setkey != NULL;
 656 }
 657 EXPORT_SYMBOL_GPL(crypto_hash_alg_has_setkey);
 658
 659 MODULE_LICENSE("GPL");
 660 MODULE_DESCRIPTION("Asynchronous cryptographic hash type");