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 <net/netlink.h>
  27
  28 #include "internal.h"
  29
  30 struct ahash_request_priv {
  31         crypto_completion_t complete;
  32         void *data;
  33         u8 *result;
  34         u32 flags;
  35         void *ubuf[] CRYPTO_MINALIGN_ATTR;
  36 };
  37
  38 static inline struct ahash_alg *crypto_ahash_alg(struct crypto_ahash *hash)
  39 {
  40         return container_of(crypto_hash_alg_common(hash), struct ahash_alg,
  41                             halg);
  42 }
  43
  44 static int hash_walk_next(struct crypto_hash_walk *walk)
  45 {
  46         unsigned int alignmask = walk->alignmask;
  47         unsigned int offset = walk->offset;
  48         unsigned int nbytes = min(walk->entrylen,
  49                                   ((unsigned int)(PAGE_SIZE)) - offset);
  50
  51         if (walk->flags & CRYPTO_ALG_ASYNC)
  52                 walk->data = kmap(walk->pg);
  53         else
  54                 walk->data = kmap_atomic(walk->pg);
  55         walk->data += offset;
  56
  57         if (offset & alignmask) {
  58                 unsigned int unaligned = alignmask + 1 - (offset & alignmask);
  59
  60                 if (nbytes > unaligned)
  61                         nbytes = unaligned;
  62         }
  63
  64         walk->entrylen -= nbytes;
  65         return nbytes;
  66 }
  67
  68 static int hash_walk_new_entry(struct crypto_hash_walk *walk)
  69 {
  70         struct scatterlist *sg;
  71
  72         sg = walk->sg;
  73         walk->offset = sg->offset;
  74         walk->pg = sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
  75         walk->offset = offset_in_page(walk->offset);
  76         walk->entrylen = sg->length;
  77
  78         if (walk->entrylen > walk->total)
  79                 walk->entrylen = walk->total;
  80         walk->total -= walk->entrylen;
  81
  82         return hash_walk_next(walk);
  83 }
  84
  85 int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
  86 {
  87         unsigned int alignmask = walk->alignmask;
  88
  89         walk->data -= walk->offset;
  90
  91         if (walk->entrylen && (walk->offset & alignmask) && !err) {
  92                 unsigned int nbytes;
  93
  94                 walk->offset = ALIGN(walk->offset, alignmask + 1);
  95                 nbytes = min(walk->entrylen,
  96                              (unsigned int)(PAGE_SIZE - walk->offset));
  97                 if (nbytes) {
  98                         walk->entrylen -= nbytes;
  99                         walk->data += walk->offset;
 100                         return nbytes;
 101                 }
 102         }
 103
 104         if (walk->flags & CRYPTO_ALG_ASYNC)
 105                 kunmap(walk->pg);
 106         else {
 107                 kunmap_atomic(walk->data);
 108                 /*
 109                  * The may sleep test only makes sense for sync users.
 110                  * Async users don't need to sleep here anyway.
 111                  */
 112                 crypto_yield(walk->flags);
 113         }
 114
 115         if (err)
 116                 return err;
 117
 118         if (walk->entrylen) {
 119                 walk->offset = 0;
 120                 walk->pg++;
 121                 return hash_walk_next(walk);
 122         }
 123
 124         if (!walk->total)
 125                 return 0;
 126
 127         walk->sg = sg_next(walk->sg);
 128
 129         return hash_walk_new_entry(walk);
 130 }
 131 EXPORT_SYMBOL_GPL(crypto_hash_walk_done);
 132
 133 int crypto_hash_walk_first(struct ahash_request *req,
 134                            struct crypto_hash_walk *walk)
 135 {
 136         walk->total = req->nbytes;
 137
 138         if (!walk->total) {
 139                 walk->entrylen = 0;
 140                 return 0;
 141         }
 142
 143         walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
 144         walk->sg = req->src;
 145         walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK;
 146
 147         return hash_walk_new_entry(walk);
 148 }
 149 EXPORT_SYMBOL_GPL(crypto_hash_walk_first);
 150
 151 int crypto_ahash_walk_first(struct ahash_request *req,
 152                             struct crypto_hash_walk *walk)
 153 {
 154         walk->total = req->nbytes;
 155
 156         if (!walk->total) {
 157                 walk->entrylen = 0;
 158                 return 0;
 159         }
 160
 161         walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
 162         walk->sg = req->src;
 163         walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK;
 164         walk->flags |= CRYPTO_ALG_ASYNC;
 165
 166         BUILD_BUG_ON(CRYPTO_TFM_REQ_MASK & CRYPTO_ALG_ASYNC);
 167
 168         return hash_walk_new_entry(walk);
 169 }
 170 EXPORT_SYMBOL_GPL(crypto_ahash_walk_first);
 171
 172 static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,
 173                                 unsigned int keylen)
 174 {
 175         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 176         int ret;
 177         u8 *buffer, *alignbuffer;
 178         unsigned long absize;
 179
 180         absize = keylen + alignmask;
 181         buffer = kmalloc(absize, GFP_KERNEL);
 182         if (!buffer)
 183                 return -ENOMEM;
 184
 185         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 186         memcpy(alignbuffer, key, keylen);
 187         ret = tfm->setkey(tfm, alignbuffer, keylen);
 188         kzfree(buffer);
 189         return ret;
 190 }
 191
 192 static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
 193                           unsigned int keylen)
 194 {
 195         return -ENOSYS;
 196 }
 197
 198 static void ahash_set_needkey(struct crypto_ahash *tfm)
 199 {
 200         const struct hash_alg_common *alg = crypto_hash_alg_common(tfm);
 201
 202         if (tfm->setkey != ahash_nosetkey &&
 203             !(alg->base.cra_flags & CRYPTO_ALG_OPTIONAL_KEY))
 204                 crypto_ahash_set_flags(tfm, CRYPTO_TFM_NEED_KEY);
 205 }
 206
 207 int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
 208                         unsigned int keylen)
 209 {
 210         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 211         int err;
 212
 213         if ((unsigned long)key & alignmask)
 214                 err = ahash_setkey_unaligned(tfm, key, keylen);
 215         else
 216                 err = tfm->setkey(tfm, key, keylen);
 217
 218         if (unlikely(err)) {
 219                 ahash_set_needkey(tfm);
 220                 return err;
 221         }
 222
 223         crypto_ahash_clear_flags(tfm, CRYPTO_TFM_NEED_KEY);
 224         return 0;
 225 }
 226 EXPORT_SYMBOL_GPL(crypto_ahash_setkey);
 227
 228 static inline unsigned int ahash_align_buffer_size(unsigned len,
 229                                                    unsigned long mask)
 230 {
 231         return len + (mask & ~(crypto_tfm_ctx_alignment() - 1));
 232 }
 233
 234 static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt)
 235 {
 236         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 237         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 238         unsigned int ds = crypto_ahash_digestsize(tfm);
 239         struct ahash_request_priv *priv;
 240
 241         priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
 242                        (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
 243                        GFP_KERNEL : GFP_ATOMIC);
 244         if (!priv)
 245                 return -ENOMEM;
 246
 247         /*
 248          * WARNING: Voodoo programming below!
 249          *
 250          * The code below is obscure and hard to understand, thus explanation
 251          * is necessary. See include/crypto/hash.h and include/linux/crypto.h
 252          * to understand the layout of structures used here!
 253          *
 254          * The code here will replace portions of the ORIGINAL request with
 255          * pointers to new code and buffers so the hashing operation can store
 256          * the result in aligned buffer. We will call the modified request
 257          * an ADJUSTED request.
 258          *
 259          * The newly mangled request will look as such:
 260          *
 261          * req {
 262          *   .result        = ADJUSTED[new aligned buffer]
 263          *   .base.complete = ADJUSTED[pointer to completion function]
 264          *   .base.data     = ADJUSTED[*req (pointer to self)]
 265          *   .priv          = ADJUSTED[new priv] {
 266          *           .result   = ORIGINAL(result)
 267          *           .complete = ORIGINAL(base.complete)
 268          *           .data     = ORIGINAL(base.data)
 269          *   }
 270          */
 271
 272         priv->result = req->result;
 273         priv->complete = req->base.complete;
 274         priv->data = req->base.data;
 275         priv->flags = req->base.flags;
 276
 277         /*
 278          * WARNING: We do not backup req->priv here! The req->priv
 279          *          is for internal use of the Crypto API and the
 280          *          user must _NOT_ _EVER_ depend on it's content!
 281          */
 282
 283         req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
 284         req->base.complete = cplt;
 285         req->base.data = req;
 286         req->priv = priv;
 287
 288         return 0;
 289 }
 290
 291 static void ahash_restore_req(struct ahash_request *req, int err)
 292 {
 293         struct ahash_request_priv *priv = req->priv;
 294
 295         if (!err)
 296                 memcpy(priv->result, req->result,
 297                        crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
 298
 299         /* Restore the original crypto request. */
 300         req->result = priv->result;
 301
 302         ahash_request_set_callback(req, priv->flags,
 303                                    priv->complete, priv->data);
 304         req->priv = NULL;
 305
 306         /* Free the req->priv.priv from the ADJUSTED request. */
 307         kzfree(priv);
 308 }
 309
 310 static void ahash_notify_einprogress(struct ahash_request *req)
 311 {
 312         struct ahash_request_priv *priv = req->priv;
 313         struct crypto_async_request oreq;
 314
 315         oreq.data = priv->data;
 316
 317         priv->complete(&oreq, -EINPROGRESS);
 318 }
 319
 320 static void ahash_op_unaligned_done(struct crypto_async_request *req, int err)
 321 {
 322         struct ahash_request *areq = req->data;
 323
 324         if (err == -EINPROGRESS) {
 325                 ahash_notify_einprogress(areq);
 326                 return;
 327         }
 328
 329         /*
 330          * Restore the original request, see ahash_op_unaligned() for what
 331          * goes where.
 332          *
 333          * The "struct ahash_request *req" here is in fact the "req.base"
 334          * from the ADJUSTED request from ahash_op_unaligned(), thus as it
 335          * is a pointer to self, it is also the ADJUSTED "req" .
 336          */
 337
 338         /* First copy req->result into req->priv.result */
 339         ahash_restore_req(areq, err);
 340
 341         /* Complete the ORIGINAL request. */
 342         areq->base.complete(&areq->base, err);
 343 }
 344
 345 static int ahash_op_unaligned(struct ahash_request *req,
 346                               int (*op)(struct ahash_request *))
 347 {
 348         int err;
 349
 350         err = ahash_save_req(req, ahash_op_unaligned_done);
 351         if (err)
 352                 return err;
 353
 354         err = op(req);
 355         if (err == -EINPROGRESS ||
 356             (err == -EBUSY && (ahash_request_flags(req) &
 357                                CRYPTO_TFM_REQ_MAY_BACKLOG)))
 358                 return err;
 359
 360         ahash_restore_req(req, err);
 361
 362         return err;
 363 }
 364
 365 static int crypto_ahash_op(struct ahash_request *req,
 366                            int (*op)(struct ahash_request *))
 367 {
 368         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 369         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 370
 371         if ((unsigned long)req->result & alignmask)
 372                 return ahash_op_unaligned(req, op);
 373
 374         return op(req);
 375 }
 376
 377 int crypto_ahash_final(struct ahash_request *req)
 378 {
 379         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
 380 }
 381 EXPORT_SYMBOL_GPL(crypto_ahash_final);
 382
 383 int crypto_ahash_finup(struct ahash_request *req)
 384 {
 385         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
 386 }
 387 EXPORT_SYMBOL_GPL(crypto_ahash_finup);
 388
 389 int crypto_ahash_digest(struct ahash_request *req)
 390 {
 391         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 392
 393         if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
 394                 return -ENOKEY;
 395
 396         return crypto_ahash_op(req, tfm->digest);
 397 }
 398 EXPORT_SYMBOL_GPL(crypto_ahash_digest);
 399
 400 static void ahash_def_finup_done2(struct crypto_async_request *req, int err)
 401 {
 402         struct ahash_request *areq = req->data;
 403
 404         if (err == -EINPROGRESS)
 405                 return;
 406
 407         ahash_restore_req(areq, err);
 408
 409         areq->base.complete(&areq->base, err);
 410 }
 411
 412 static int ahash_def_finup_finish1(struct ahash_request *req, int err)
 413 {
 414         if (err)
 415                 goto out;
 416
 417         req->base.complete = ahash_def_finup_done2;
 418
 419         err = crypto_ahash_reqtfm(req)->final(req);
 420         if (err == -EINPROGRESS ||
 421             (err == -EBUSY && (ahash_request_flags(req) &
 422                                CRYPTO_TFM_REQ_MAY_BACKLOG)))
 423                 return err;
 424
 425 out:
 426         ahash_restore_req(req, err);
 427         return err;
 428 }
 429
 430 static void ahash_def_finup_done1(struct crypto_async_request *req, int err)
 431 {
 432         struct ahash_request *areq = req->data;
 433
 434         if (err == -EINPROGRESS) {
 435                 ahash_notify_einprogress(areq);
 436                 return;
 437         }
 438
 439         areq->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
 440
 441         err = ahash_def_finup_finish1(areq, err);
 442         if (areq->priv)
 443                 return;
 444
 445         areq->base.complete(&areq->base, err);
 446 }
 447
 448 static int ahash_def_finup(struct ahash_request *req)
 449 {
 450         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 451         int err;
 452
 453         err = ahash_save_req(req, ahash_def_finup_done1);
 454         if (err)
 455                 return err;
 456
 457         err = tfm->update(req);
 458         if (err == -EINPROGRESS ||
 459             (err == -EBUSY && (ahash_request_flags(req) &
 460                                CRYPTO_TFM_REQ_MAY_BACKLOG)))
 461                 return err;
 462
 463         return ahash_def_finup_finish1(req, err);
 464 }
 465
 466 static int ahash_no_export(struct ahash_request *req, void *out)
 467 {
 468         return -ENOSYS;
 469 }
 470
 471 static int ahash_no_import(struct ahash_request *req, const void *in)
 472 {
 473         return -ENOSYS;
 474 }
 475
 476 static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
 477 {
 478         struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
 479         struct ahash_alg *alg = crypto_ahash_alg(hash);
 480
 481         hash->setkey = ahash_nosetkey;
 482         hash->export = ahash_no_export;
 483         hash->import = ahash_no_import;
 484
 485         if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
 486                 return crypto_init_shash_ops_async(tfm);
 487
 488         hash->init = alg->init;
 489         hash->update = alg->update;
 490         hash->final = alg->final;
 491         hash->finup = alg->finup ?: ahash_def_finup;
 492         hash->digest = alg->digest;
 493
 494         if (alg->setkey) {
 495                 hash->setkey = alg->setkey;
 496                 ahash_set_needkey(hash);
 497         }
 498         if (alg->export)
 499                 hash->export = alg->export;
 500         if (alg->import)
 501                 hash->import = alg->import;
 502
 503         return 0;
 504 }
 505
 506 static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
 507 {
 508         if (alg->cra_type != &crypto_ahash_type)
 509                 return sizeof(struct crypto_shash *);
 510
 511         return crypto_alg_extsize(alg);
 512 }
 513
 514 #ifdef CONFIG_NET
 515 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 516 {
 517         struct crypto_report_hash rhash;
 518
 519         strncpy(rhash.type, "ahash", sizeof(rhash.type));
 520
 521         rhash.blocksize = alg->cra_blocksize;
 522         rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
 523
 524         if (nla_put(skb, CRYPTOCFGA_REPORT_HASH,
 525                     sizeof(struct crypto_report_hash), &rhash))
 526                 goto nla_put_failure;
 527         return 0;
 528
 529 nla_put_failure:
 530         return -EMSGSIZE;
 531 }
 532 #else
 533 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 534 {
 535         return -ENOSYS;
 536 }
 537 #endif
 538
 539 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 540         __attribute__ ((unused));
 541 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 542 {
 543         seq_printf(m, "type         : ahash\n");
 544         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 545                                              "yes" : "no");
 546         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 547         seq_printf(m, "digestsize   : %u\n",
 548                    __crypto_hash_alg_common(alg)->digestsize);
 549 }
 550
 551 const struct crypto_type crypto_ahash_type = {
 552         .extsize = crypto_ahash_extsize,
 553         .init_tfm = crypto_ahash_init_tfm,
 554 #ifdef CONFIG_PROC_FS
 555         .show = crypto_ahash_show,
 556 #endif
 557         .report = crypto_ahash_report,
 558         .maskclear = ~CRYPTO_ALG_TYPE_MASK,
 559         .maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
 560         .type = CRYPTO_ALG_TYPE_AHASH,
 561         .tfmsize = offsetof(struct crypto_ahash, base),
 562 };
 563 EXPORT_SYMBOL_GPL(crypto_ahash_type);
 564
 565 struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
 566                                         u32 mask)
 567 {
 568         return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
 569 }
 570 EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
 571
 572 int crypto_has_ahash(const char *alg_name, u32 type, u32 mask)
 573 {
 574         return crypto_type_has_alg(alg_name, &crypto_ahash_type, type, mask);
 575 }
 576 EXPORT_SYMBOL_GPL(crypto_has_ahash);
 577
 578 static int ahash_prepare_alg(struct ahash_alg *alg)
 579 {
 580         struct crypto_alg *base = &alg->halg.base;
 581
 582         if (alg->halg.digestsize > PAGE_SIZE / 8 ||
 583             alg->halg.statesize > PAGE_SIZE / 8 ||
 584             alg->halg.statesize == 0)
 585                 return -EINVAL;
 586
 587         base->cra_type = &crypto_ahash_type;
 588         base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
 589         base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
 590
 591         return 0;
 592 }
 593
 594 int crypto_register_ahash(struct ahash_alg *alg)
 595 {
 596         struct crypto_alg *base = &alg->halg.base;
 597         int err;
 598
 599         err = ahash_prepare_alg(alg);
 600         if (err)
 601                 return err;
 602
 603         return crypto_register_alg(base);
 604 }
 605 EXPORT_SYMBOL_GPL(crypto_register_ahash);
 606
 607 int crypto_unregister_ahash(struct ahash_alg *alg)
 608 {
 609         return crypto_unregister_alg(&alg->halg.base);
 610 }
 611 EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
 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");