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         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
 368 }
 369 EXPORT_SYMBOL_GPL(crypto_ahash_final);
 370
 371 int crypto_ahash_finup(struct ahash_request *req)
 372 {
 373         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
 374 }
 375 EXPORT_SYMBOL_GPL(crypto_ahash_finup);
 376
 377 int crypto_ahash_digest(struct ahash_request *req)
 378 {
 379         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 380
 381         if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
 382                 return -ENOKEY;
 383
 384         return crypto_ahash_op(req, tfm->digest);
 385 }
 386 EXPORT_SYMBOL_GPL(crypto_ahash_digest);
 387
 388 static void ahash_def_finup_done2(struct crypto_async_request *req, int err)
 389 {
 390         struct ahash_request *areq = req->data;
 391
 392         if (err == -EINPROGRESS)
 393                 return;
 394
 395         ahash_restore_req(areq, err);
 396
 397         areq->base.complete(&areq->base, err);
 398 }
 399
 400 static int ahash_def_finup_finish1(struct ahash_request *req, int err)
 401 {
 402         if (err)
 403                 goto out;
 404
 405         req->base.complete = ahash_def_finup_done2;
 406
 407         err = crypto_ahash_reqtfm(req)->final(req);
 408         if (err == -EINPROGRESS || err == -EBUSY)
 409                 return err;
 410
 411 out:
 412         ahash_restore_req(req, err);
 413         return err;
 414 }
 415
 416 static void ahash_def_finup_done1(struct crypto_async_request *req, int err)
 417 {
 418         struct ahash_request *areq = req->data;
 419
 420         if (err == -EINPROGRESS) {
 421                 ahash_notify_einprogress(areq);
 422                 return;
 423         }
 424
 425         areq->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
 426
 427         err = ahash_def_finup_finish1(areq, err);
 428         if (areq->priv)
 429                 return;
 430
 431         areq->base.complete(&areq->base, err);
 432 }
 433
 434 static int ahash_def_finup(struct ahash_request *req)
 435 {
 436         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 437         int err;
 438
 439         err = ahash_save_req(req, ahash_def_finup_done1);
 440         if (err)
 441                 return err;
 442
 443         err = tfm->update(req);
 444         if (err == -EINPROGRESS || err == -EBUSY)
 445                 return err;
 446
 447         return ahash_def_finup_finish1(req, err);
 448 }
 449
 450 static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
 451 {
 452         struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
 453         struct ahash_alg *alg = crypto_ahash_alg(hash);
 454
 455         hash->setkey = ahash_nosetkey;
 456
 457         if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
 458                 return crypto_init_shash_ops_async(tfm);
 459
 460         hash->init = alg->init;
 461         hash->update = alg->update;
 462         hash->final = alg->final;
 463         hash->finup = alg->finup ?: ahash_def_finup;
 464         hash->digest = alg->digest;
 465         hash->export = alg->export;
 466         hash->import = alg->import;
 467
 468         if (alg->setkey) {
 469                 hash->setkey = alg->setkey;
 470                 if (!(alg->halg.base.cra_flags & CRYPTO_ALG_OPTIONAL_KEY))
 471                         crypto_ahash_set_flags(hash, CRYPTO_TFM_NEED_KEY);
 472         }
 473
 474         return 0;
 475 }
 476
 477 static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
 478 {
 479         if (alg->cra_type != &crypto_ahash_type)
 480                 return sizeof(struct crypto_shash *);
 481
 482         return crypto_alg_extsize(alg);
 483 }
 484
 485 #ifdef CONFIG_NET
 486 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 487 {
 488         struct crypto_report_hash rhash;
 489
 490         strncpy(rhash.type, "ahash", sizeof(rhash.type));
 491
 492         rhash.blocksize = alg->cra_blocksize;
 493         rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
 494
 495         if (nla_put(skb, CRYPTOCFGA_REPORT_HASH,
 496                     sizeof(struct crypto_report_hash), &rhash))
 497                 goto nla_put_failure;
 498         return 0;
 499
 500 nla_put_failure:
 501         return -EMSGSIZE;
 502 }
 503 #else
 504 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 505 {
 506         return -ENOSYS;
 507 }
 508 #endif
 509
 510 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 511         __maybe_unused;
 512 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 513 {
 514         seq_printf(m, "type         : ahash\n");
 515         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 516                                              "yes" : "no");
 517         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 518         seq_printf(m, "digestsize   : %u\n",
 519                    __crypto_hash_alg_common(alg)->digestsize);
 520 }
 521
 522 const struct crypto_type crypto_ahash_type = {
 523         .extsize = crypto_ahash_extsize,
 524         .init_tfm = crypto_ahash_init_tfm,
 525 #ifdef CONFIG_PROC_FS
 526         .show = crypto_ahash_show,
 527 #endif
 528         .report = crypto_ahash_report,
 529         .maskclear = ~CRYPTO_ALG_TYPE_MASK,
 530         .maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
 531         .type = CRYPTO_ALG_TYPE_AHASH,
 532         .tfmsize = offsetof(struct crypto_ahash, base),
 533 };
 534 EXPORT_SYMBOL_GPL(crypto_ahash_type);
 535
 536 struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
 537                                         u32 mask)
 538 {
 539         return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
 540 }
 541 EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
 542
 543 int crypto_has_ahash(const char *alg_name, u32 type, u32 mask)
 544 {
 545         return crypto_type_has_alg(alg_name, &crypto_ahash_type, type, mask);
 546 }
 547 EXPORT_SYMBOL_GPL(crypto_has_ahash);
 548
 549 static int ahash_prepare_alg(struct ahash_alg *alg)
 550 {
 551         struct crypto_alg *base = &alg->halg.base;
 552
 553         if (alg->halg.digestsize > PAGE_SIZE / 8 ||
 554             alg->halg.statesize > PAGE_SIZE / 8 ||
 555             alg->halg.statesize == 0)
 556                 return -EINVAL;
 557
 558         base->cra_type = &crypto_ahash_type;
 559         base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
 560         base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
 561
 562         return 0;
 563 }
 564
 565 int crypto_register_ahash(struct ahash_alg *alg)
 566 {
 567         struct crypto_alg *base = &alg->halg.base;
 568         int err;
 569
 570         err = ahash_prepare_alg(alg);
 571         if (err)
 572                 return err;
 573
 574         return crypto_register_alg(base);
 575 }
 576 EXPORT_SYMBOL_GPL(crypto_register_ahash);
 577
 578 int crypto_unregister_ahash(struct ahash_alg *alg)
 579 {
 580         return crypto_unregister_alg(&alg->halg.base);
 581 }
 582 EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
 583
 584 int crypto_register_ahashes(struct ahash_alg *algs, int count)
 585 {
 586         int i, ret;
 587
 588         for (i = 0; i < count; i++) {
 589                 ret = crypto_register_ahash(&algs[i]);
 590                 if (ret)
 591                         goto err;
 592         }
 593
 594         return 0;
 595
 596 err:
 597         for (--i; i >= 0; --i)
 598                 crypto_unregister_ahash(&algs[i]);
 599
 600         return ret;
 601 }
 602 EXPORT_SYMBOL_GPL(crypto_register_ahashes);
 603
 604 void crypto_unregister_ahashes(struct ahash_alg *algs, int count)
 605 {
 606         int i;
 607
 608         for (i = count - 1; i >= 0; --i)
 609                 crypto_unregister_ahash(&algs[i]);
 610 }
 611 EXPORT_SYMBOL_GPL(crypto_unregister_ahashes);
 612
 613 int ahash_register_instance(struct crypto_template *tmpl,
 614                             struct ahash_instance *inst)
 615 {
 616         int err;
 617
 618         err = ahash_prepare_alg(&inst->alg);
 619         if (err)
 620                 return err;
 621
 622         return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
 623 }
 624 EXPORT_SYMBOL_GPL(ahash_register_instance);
 625
 626 void ahash_free_instance(struct crypto_instance *inst)
 627 {
 628         crypto_drop_spawn(crypto_instance_ctx(inst));
 629         kfree(ahash_instance(inst));
 630 }
 631 EXPORT_SYMBOL_GPL(ahash_free_instance);
 632
 633 int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
 634                             struct hash_alg_common *alg,
 635                             struct crypto_instance *inst)
 636 {
 637         return crypto_init_spawn2(&spawn->base, &alg->base, inst,
 638                                   &crypto_ahash_type);
 639 }
 640 EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn);
 641
 642 struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
 643 {
 644         struct crypto_alg *alg;
 645
 646         alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask);
 647         return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg);
 648 }
 649 EXPORT_SYMBOL_GPL(ahash_attr_alg);
 650
 651 bool crypto_hash_alg_has_setkey(struct hash_alg_common *halg)
 652 {
 653         struct crypto_alg *alg = &halg->base;
 654
 655         if (alg->cra_type != &crypto_ahash_type)
 656                 return crypto_shash_alg_has_setkey(__crypto_shash_alg(alg));
 657
 658         return __crypto_ahash_alg(alg)->setkey != NULL;
 659 }
 660 EXPORT_SYMBOL_GPL(crypto_hash_alg_has_setkey);
 661
 662 MODULE_LICENSE("GPL");
 663 MODULE_DESCRIPTION("Asynchronous cryptographic hash type");