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         unsigned int nbytes = walk->entrylen;
  90
  91         walk->data -= walk->offset;
  92
  93         if (nbytes && walk->offset & alignmask && !err) {
  94                 walk->offset = ALIGN(walk->offset, alignmask + 1);
  95                 nbytes = min(nbytes,
  96                              ((unsigned int)(PAGE_SIZE)) - walk->offset);
  97                 walk->entrylen -= nbytes;
  98
  99                 if (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 (nbytes) {
 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 int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
 194                         unsigned int keylen)
 195 {
 196         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 197         int err;
 198
 199         if ((unsigned long)key & alignmask)
 200                 err = ahash_setkey_unaligned(tfm, key, keylen);
 201         else
 202                 err = tfm->setkey(tfm, key, keylen);
 203
 204         if (err)
 205                 return err;
 206
 207         crypto_ahash_clear_flags(tfm, CRYPTO_TFM_NEED_KEY);
 208         return 0;
 209 }
 210 EXPORT_SYMBOL_GPL(crypto_ahash_setkey);
 211
 212 static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
 213                           unsigned int keylen)
 214 {
 215         return -ENOSYS;
 216 }
 217
 218 static inline unsigned int ahash_align_buffer_size(unsigned len,
 219                                                    unsigned long mask)
 220 {
 221         return len + (mask & ~(crypto_tfm_ctx_alignment() - 1));
 222 }
 223
 224 static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt)
 225 {
 226         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 227         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 228         unsigned int ds = crypto_ahash_digestsize(tfm);
 229         struct ahash_request_priv *priv;
 230
 231         priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
 232                        (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
 233                        GFP_KERNEL : GFP_ATOMIC);
 234         if (!priv)
 235                 return -ENOMEM;
 236
 237         /*
 238          * WARNING: Voodoo programming below!
 239          *
 240          * The code below is obscure and hard to understand, thus explanation
 241          * is necessary. See include/crypto/hash.h and include/linux/crypto.h
 242          * to understand the layout of structures used here!
 243          *
 244          * The code here will replace portions of the ORIGINAL request with
 245          * pointers to new code and buffers so the hashing operation can store
 246          * the result in aligned buffer. We will call the modified request
 247          * an ADJUSTED request.
 248          *
 249          * The newly mangled request will look as such:
 250          *
 251          * req {
 252          *   .result        = ADJUSTED[new aligned buffer]
 253          *   .base.complete = ADJUSTED[pointer to completion function]
 254          *   .base.data     = ADJUSTED[*req (pointer to self)]
 255          *   .priv          = ADJUSTED[new priv] {
 256          *           .result   = ORIGINAL(result)
 257          *           .complete = ORIGINAL(base.complete)
 258          *           .data     = ORIGINAL(base.data)
 259          *   }
 260          */
 261
 262         priv->result = req->result;
 263         priv->complete = req->base.complete;
 264         priv->data = req->base.data;
 265         priv->flags = req->base.flags;
 266
 267         /*
 268          * WARNING: We do not backup req->priv here! The req->priv
 269          *          is for internal use of the Crypto API and the
 270          *          user must _NOT_ _EVER_ depend on it's content!
 271          */
 272
 273         req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
 274         req->base.complete = cplt;
 275         req->base.data = req;
 276         req->priv = priv;
 277
 278         return 0;
 279 }
 280
 281 static void ahash_restore_req(struct ahash_request *req, int err)
 282 {
 283         struct ahash_request_priv *priv = req->priv;
 284
 285         if (!err)
 286                 memcpy(priv->result, req->result,
 287                        crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
 288
 289         /* Restore the original crypto request. */
 290         req->result = priv->result;
 291
 292         ahash_request_set_callback(req, priv->flags,
 293                                    priv->complete, priv->data);
 294         req->priv = NULL;
 295
 296         /* Free the req->priv.priv from the ADJUSTED request. */
 297         kzfree(priv);
 298 }
 299
 300 static void ahash_notify_einprogress(struct ahash_request *req)
 301 {
 302         struct ahash_request_priv *priv = req->priv;
 303         struct crypto_async_request oreq;
 304
 305         oreq.data = priv->data;
 306
 307         priv->complete(&oreq, -EINPROGRESS);
 308 }
 309
 310 static void ahash_op_unaligned_done(struct crypto_async_request *req, int err)
 311 {
 312         struct ahash_request *areq = req->data;
 313
 314         if (err == -EINPROGRESS) {
 315                 ahash_notify_einprogress(areq);
 316                 return;
 317         }
 318
 319         /*
 320          * Restore the original request, see ahash_op_unaligned() for what
 321          * goes where.
 322          *
 323          * The "struct ahash_request *req" here is in fact the "req.base"
 324          * from the ADJUSTED request from ahash_op_unaligned(), thus as it
 325          * is a pointer to self, it is also the ADJUSTED "req" .
 326          */
 327
 328         /* First copy req->result into req->priv.result */
 329         ahash_restore_req(areq, err);
 330
 331         /* Complete the ORIGINAL request. */
 332         areq->base.complete(&areq->base, err);
 333 }
 334
 335 static int ahash_op_unaligned(struct ahash_request *req,
 336                               int (*op)(struct ahash_request *))
 337 {
 338         int err;
 339
 340         err = ahash_save_req(req, ahash_op_unaligned_done);
 341         if (err)
 342                 return err;
 343
 344         err = op(req);
 345         if (err == -EINPROGRESS || err == -EBUSY)
 346                 return err;
 347
 348         ahash_restore_req(req, err);
 349
 350         return err;
 351 }
 352
 353 static int crypto_ahash_op(struct ahash_request *req,
 354                            int (*op)(struct ahash_request *))
 355 {
 356         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 357         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 358
 359         if ((unsigned long)req->result & alignmask)
 360                 return ahash_op_unaligned(req, op);
 361
 362         return op(req);
 363 }
 364
 365 int crypto_ahash_final(struct ahash_request *req)
 366 {
 367         int ret;
 368
 369         ret = crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
 370         crypto_stat_ahash_final(req, ret);
 371         return ret;
 372 }
 373 EXPORT_SYMBOL_GPL(crypto_ahash_final);
 374
 375 int crypto_ahash_finup(struct ahash_request *req)
 376 {
 377         int ret;
 378
 379         ret = crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
 380         crypto_stat_ahash_final(req, ret);
 381         return ret;
 382 }
 383 EXPORT_SYMBOL_GPL(crypto_ahash_finup);
 384
 385 int crypto_ahash_digest(struct ahash_request *req)
 386 {
 387         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 388         int ret;
 389
 390         if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
 391                 ret = -ENOKEY;
 392         else
 393                 ret = crypto_ahash_op(req, tfm->digest);
 394         crypto_stat_ahash_final(req, ret);
 395         return ret;
 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 crypto_ahash_init_tfm(struct crypto_tfm *tfm)
 462 {
 463         struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
 464         struct ahash_alg *alg = crypto_ahash_alg(hash);
 465
 466         hash->setkey = ahash_nosetkey;
 467
 468         if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
 469                 return crypto_init_shash_ops_async(tfm);
 470
 471         hash->init = alg->init;
 472         hash->update = alg->update;
 473         hash->final = alg->final;
 474         hash->finup = alg->finup ?: ahash_def_finup;
 475         hash->digest = alg->digest;
 476         hash->export = alg->export;
 477         hash->import = alg->import;
 478
 479         if (alg->setkey) {
 480                 hash->setkey = alg->setkey;
 481                 if (!(alg->halg.base.cra_flags & CRYPTO_ALG_OPTIONAL_KEY))
 482                         crypto_ahash_set_flags(hash, CRYPTO_TFM_NEED_KEY);
 483         }
 484
 485         return 0;
 486 }
 487
 488 static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
 489 {
 490         if (alg->cra_type != &crypto_ahash_type)
 491                 return sizeof(struct crypto_shash *);
 492
 493         return crypto_alg_extsize(alg);
 494 }
 495
 496 #ifdef CONFIG_NET
 497 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 498 {
 499         struct crypto_report_hash rhash;
 500
 501         strncpy(rhash.type, "ahash", sizeof(rhash.type));
 502
 503         rhash.blocksize = alg->cra_blocksize;
 504         rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
 505
 506         if (nla_put(skb, CRYPTOCFGA_REPORT_HASH,
 507                     sizeof(struct crypto_report_hash), &rhash))
 508                 goto nla_put_failure;
 509         return 0;
 510
 511 nla_put_failure:
 512         return -EMSGSIZE;
 513 }
 514 #else
 515 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 516 {
 517         return -ENOSYS;
 518 }
 519 #endif
 520
 521 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 522         __maybe_unused;
 523 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 524 {
 525         seq_printf(m, "type         : ahash\n");
 526         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 527                                              "yes" : "no");
 528         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 529         seq_printf(m, "digestsize   : %u\n",
 530                    __crypto_hash_alg_common(alg)->digestsize);
 531 }
 532
 533 const struct crypto_type crypto_ahash_type = {
 534         .extsize = crypto_ahash_extsize,
 535         .init_tfm = crypto_ahash_init_tfm,
 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 EXPORT_SYMBOL_GPL(crypto_ahash_type);
 546
 547 struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
 548                                         u32 mask)
 549 {
 550         return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
 551 }
 552 EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
 553
 554 int crypto_has_ahash(const char *alg_name, u32 type, u32 mask)
 555 {
 556         return crypto_type_has_alg(alg_name, &crypto_ahash_type, type, mask);
 557 }
 558 EXPORT_SYMBOL_GPL(crypto_has_ahash);
 559
 560 static int ahash_prepare_alg(struct ahash_alg *alg)
 561 {
 562         struct crypto_alg *base = &alg->halg.base;
 563
 564         if (alg->halg.digestsize > HASH_MAX_DIGESTSIZE ||
 565             alg->halg.statesize > HASH_MAX_STATESIZE ||
 566             alg->halg.statesize == 0)
 567                 return -EINVAL;
 568
 569         base->cra_type = &crypto_ahash_type;
 570         base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
 571         base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
 572
 573         return 0;
 574 }
 575
 576 int crypto_register_ahash(struct ahash_alg *alg)
 577 {
 578         struct crypto_alg *base = &alg->halg.base;
 579         int err;
 580
 581         err = ahash_prepare_alg(alg);
 582         if (err)
 583                 return err;
 584
 585         return crypto_register_alg(base);
 586 }
 587 EXPORT_SYMBOL_GPL(crypto_register_ahash);
 588
 589 int crypto_unregister_ahash(struct ahash_alg *alg)
 590 {
 591         return crypto_unregister_alg(&alg->halg.base);
 592 }
 593 EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
 594
 595 int crypto_register_ahashes(struct ahash_alg *algs, int count)
 596 {
 597         int i, ret;
 598
 599         for (i = 0; i < count; i++) {
 600                 ret = crypto_register_ahash(&algs[i]);
 601                 if (ret)
 602                         goto err;
 603         }
 604
 605         return 0;
 606
 607 err:
 608         for (--i; i >= 0; --i)
 609                 crypto_unregister_ahash(&algs[i]);
 610
 611         return ret;
 612 }
 613 EXPORT_SYMBOL_GPL(crypto_register_ahashes);
 614
 615 void crypto_unregister_ahashes(struct ahash_alg *algs, int count)
 616 {
 617         int i;
 618
 619         for (i = count - 1; i >= 0; --i)
 620                 crypto_unregister_ahash(&algs[i]);
 621 }
 622 EXPORT_SYMBOL_GPL(crypto_unregister_ahashes);
 623
 624 int ahash_register_instance(struct crypto_template *tmpl,
 625                             struct ahash_instance *inst)
 626 {
 627         int err;
 628
 629         err = ahash_prepare_alg(&inst->alg);
 630         if (err)
 631                 return err;
 632
 633         return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
 634 }
 635 EXPORT_SYMBOL_GPL(ahash_register_instance);
 636
 637 void ahash_free_instance(struct crypto_instance *inst)
 638 {
 639         crypto_drop_spawn(crypto_instance_ctx(inst));
 640         kfree(ahash_instance(inst));
 641 }
 642 EXPORT_SYMBOL_GPL(ahash_free_instance);
 643
 644 int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
 645                             struct hash_alg_common *alg,
 646                             struct crypto_instance *inst)
 647 {
 648         return crypto_init_spawn2(&spawn->base, &alg->base, inst,
 649                                   &crypto_ahash_type);
 650 }
 651 EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn);
 652
 653 struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
 654 {
 655         struct crypto_alg *alg;
 656
 657         alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask);
 658         return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg);
 659 }
 660 EXPORT_SYMBOL_GPL(ahash_attr_alg);
 661
 662 bool crypto_hash_alg_has_setkey(struct hash_alg_common *halg)
 663 {
 664         struct crypto_alg *alg = &halg->base;
 665
 666         if (alg->cra_type != &crypto_ahash_type)
 667                 return crypto_shash_alg_has_setkey(__crypto_shash_alg(alg));
 668
 669         return __crypto_ahash_alg(alg)->setkey != NULL;
 670 }
 671 EXPORT_SYMBOL_GPL(crypto_hash_alg_has_setkey);
 672
 673 MODULE_LICENSE("GPL");
 674 MODULE_DESCRIPTION("Asynchronous cryptographic hash type");