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         unsigned int nbytes = walk->entrylen;
  89
  90         walk->data -= walk->offset;
  91
  92         if (nbytes && walk->offset & alignmask && !err) {
  93                 walk->offset = ALIGN(walk->offset, alignmask + 1);
  94                 walk->data += walk->offset;
  95
  96                 nbytes = min(nbytes,
  97                              ((unsigned int)(PAGE_SIZE)) - walk->offset);
  98                 walk->entrylen -= nbytes;
  99
 100                 return nbytes;
 101         }
 102
 103         if (walk->flags & CRYPTO_ALG_ASYNC)
 104                 kunmap(walk->pg);
 105         else {
 106                 kunmap_atomic(walk->data);
 107                 /*
 108                  * The may sleep test only makes sense for sync users.
 109                  * Async users don't need to sleep here anyway.
 110                  */
 111                 crypto_yield(walk->flags);
 112         }
 113
 114         if (err)
 115                 return err;
 116
 117         if (nbytes) {
 118                 walk->offset = 0;
 119                 walk->pg++;
 120                 return hash_walk_next(walk);
 121         }
 122
 123         if (!walk->total)
 124                 return 0;
 125
 126         walk->sg = sg_next(walk->sg);
 127
 128         return hash_walk_new_entry(walk);
 129 }
 130 EXPORT_SYMBOL_GPL(crypto_hash_walk_done);
 131
 132 int crypto_hash_walk_first(struct ahash_request *req,
 133                            struct crypto_hash_walk *walk)
 134 {
 135         walk->total = req->nbytes;
 136
 137         if (!walk->total) {
 138                 walk->entrylen = 0;
 139                 return 0;
 140         }
 141
 142         walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
 143         walk->sg = req->src;
 144         walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK;
 145
 146         return hash_walk_new_entry(walk);
 147 }
 148 EXPORT_SYMBOL_GPL(crypto_hash_walk_first);
 149
 150 int crypto_ahash_walk_first(struct ahash_request *req,
 151                             struct crypto_hash_walk *walk)
 152 {
 153         walk->total = req->nbytes;
 154
 155         if (!walk->total) {
 156                 walk->entrylen = 0;
 157                 return 0;
 158         }
 159
 160         walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
 161         walk->sg = req->src;
 162         walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK;
 163         walk->flags |= CRYPTO_ALG_ASYNC;
 164
 165         BUILD_BUG_ON(CRYPTO_TFM_REQ_MASK & CRYPTO_ALG_ASYNC);
 166
 167         return hash_walk_new_entry(walk);
 168 }
 169 EXPORT_SYMBOL_GPL(crypto_ahash_walk_first);
 170
 171 int crypto_hash_walk_first_compat(struct hash_desc *hdesc,
 172                                   struct crypto_hash_walk *walk,
 173                                   struct scatterlist *sg, unsigned int len)
 174 {
 175         walk->total = len;
 176
 177         if (!walk->total) {
 178                 walk->entrylen = 0;
 179                 return 0;
 180         }
 181
 182         walk->alignmask = crypto_hash_alignmask(hdesc->tfm);
 183         walk->sg = sg;
 184         walk->flags = hdesc->flags & CRYPTO_TFM_REQ_MASK;
 185
 186         return hash_walk_new_entry(walk);
 187 }
 188
 189 static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,
 190                                 unsigned int keylen)
 191 {
 192         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 193         int ret;
 194         u8 *buffer, *alignbuffer;
 195         unsigned long absize;
 196
 197         absize = keylen + alignmask;
 198         buffer = kmalloc(absize, GFP_KERNEL);
 199         if (!buffer)
 200                 return -ENOMEM;
 201
 202         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 203         memcpy(alignbuffer, key, keylen);
 204         ret = tfm->setkey(tfm, alignbuffer, keylen);
 205         kzfree(buffer);
 206         return ret;
 207 }
 208
 209 int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
 210                         unsigned int keylen)
 211 {
 212         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 213
 214         if ((unsigned long)key & alignmask)
 215                 return ahash_setkey_unaligned(tfm, key, keylen);
 216
 217         return tfm->setkey(tfm, key, keylen);
 218 }
 219 EXPORT_SYMBOL_GPL(crypto_ahash_setkey);
 220
 221 static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
 222                           unsigned int keylen)
 223 {
 224         return -ENOSYS;
 225 }
 226
 227 static inline unsigned int ahash_align_buffer_size(unsigned len,
 228                                                    unsigned long mask)
 229 {
 230         return len + (mask & ~(crypto_tfm_ctx_alignment() - 1));
 231 }
 232
 233 static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt)
 234 {
 235         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 236         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 237         unsigned int ds = crypto_ahash_digestsize(tfm);
 238         struct ahash_request_priv *priv;
 239
 240         priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
 241                        (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
 242                        GFP_KERNEL : GFP_ATOMIC);
 243         if (!priv)
 244                 return -ENOMEM;
 245
 246         /*
 247          * WARNING: Voodoo programming below!
 248          *
 249          * The code below is obscure and hard to understand, thus explanation
 250          * is necessary. See include/crypto/hash.h and include/linux/crypto.h
 251          * to understand the layout of structures used here!
 252          *
 253          * The code here will replace portions of the ORIGINAL request with
 254          * pointers to new code and buffers so the hashing operation can store
 255          * the result in aligned buffer. We will call the modified request
 256          * an ADJUSTED request.
 257          *
 258          * The newly mangled request will look as such:
 259          *
 260          * req {
 261          *   .result        = ADJUSTED[new aligned buffer]
 262          *   .base.complete = ADJUSTED[pointer to completion function]
 263          *   .base.data     = ADJUSTED[*req (pointer to self)]
 264          *   .priv          = ADJUSTED[new priv] {
 265          *           .result   = ORIGINAL(result)
 266          *           .complete = ORIGINAL(base.complete)
 267          *           .data     = ORIGINAL(base.data)
 268          *   }
 269          */
 270
 271         priv->result = req->result;
 272         priv->complete = req->base.complete;
 273         priv->data = req->base.data;
 274         priv->flags = req->base.flags;
 275
 276         /*
 277          * WARNING: We do not backup req->priv here! The req->priv
 278          *          is for internal use of the Crypto API and the
 279          *          user must _NOT_ _EVER_ depend on it's content!
 280          */
 281
 282         req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
 283         req->base.complete = cplt;
 284         req->base.data = req;
 285         req->priv = priv;
 286
 287         return 0;
 288 }
 289
 290 static void ahash_restore_req(struct ahash_request *req, int err)
 291 {
 292         struct ahash_request_priv *priv = req->priv;
 293
 294         if (!err)
 295                 memcpy(priv->result, req->result,
 296                        crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
 297
 298         /* Restore the original crypto request. */
 299         req->result = priv->result;
 300
 301         ahash_request_set_callback(req, priv->flags,
 302                                    priv->complete, priv->data);
 303         req->priv = NULL;
 304
 305         /* Free the req->priv.priv from the ADJUSTED request. */
 306         kzfree(priv);
 307 }
 308
 309 static void ahash_notify_einprogress(struct ahash_request *req)
 310 {
 311         struct ahash_request_priv *priv = req->priv;
 312         struct crypto_async_request oreq;
 313
 314         oreq.data = priv->data;
 315
 316         priv->complete(&oreq, -EINPROGRESS);
 317 }
 318
 319 static void ahash_op_unaligned_done(struct crypto_async_request *req, int err)
 320 {
 321         struct ahash_request *areq = req->data;
 322
 323         if (err == -EINPROGRESS) {
 324                 ahash_notify_einprogress(areq);
 325                 return;
 326         }
 327
 328         /*
 329          * Restore the original request, see ahash_op_unaligned() for what
 330          * goes where.
 331          *
 332          * The "struct ahash_request *req" here is in fact the "req.base"
 333          * from the ADJUSTED request from ahash_op_unaligned(), thus as it
 334          * is a pointer to self, it is also the ADJUSTED "req" .
 335          */
 336
 337         /* First copy req->result into req->priv.result */
 338         ahash_restore_req(areq, err);
 339
 340         /* Complete the ORIGINAL request. */
 341         areq->base.complete(&areq->base, err);
 342 }
 343
 344 static int ahash_op_unaligned(struct ahash_request *req,
 345                               int (*op)(struct ahash_request *))
 346 {
 347         int err;
 348
 349         err = ahash_save_req(req, ahash_op_unaligned_done);
 350         if (err)
 351                 return err;
 352
 353         err = op(req);
 354         if (err == -EINPROGRESS ||
 355             (err == -EBUSY && (ahash_request_flags(req) &
 356                                CRYPTO_TFM_REQ_MAY_BACKLOG)))
 357                 return err;
 358
 359         ahash_restore_req(req, err);
 360
 361         return err;
 362 }
 363
 364 static int crypto_ahash_op(struct ahash_request *req,
 365                            int (*op)(struct ahash_request *))
 366 {
 367         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 368         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 369
 370         if ((unsigned long)req->result & alignmask)
 371                 return ahash_op_unaligned(req, op);
 372
 373         return op(req);
 374 }
 375
 376 int crypto_ahash_final(struct ahash_request *req)
 377 {
 378         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
 379 }
 380 EXPORT_SYMBOL_GPL(crypto_ahash_final);
 381
 382 int crypto_ahash_finup(struct ahash_request *req)
 383 {
 384         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
 385 }
 386 EXPORT_SYMBOL_GPL(crypto_ahash_finup);
 387
 388 int crypto_ahash_digest(struct ahash_request *req)
 389 {
 390         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->digest);
 391 }
 392 EXPORT_SYMBOL_GPL(crypto_ahash_digest);
 393
 394 static void ahash_def_finup_done2(struct crypto_async_request *req, int err)
 395 {
 396         struct ahash_request *areq = req->data;
 397
 398         if (err == -EINPROGRESS)
 399                 return;
 400
 401         ahash_restore_req(areq, err);
 402
 403         areq->base.complete(&areq->base, err);
 404 }
 405
 406 static int ahash_def_finup_finish1(struct ahash_request *req, int err)
 407 {
 408         if (err)
 409                 goto out;
 410
 411         req->base.complete = ahash_def_finup_done2;
 412
 413         err = crypto_ahash_reqtfm(req)->final(req);
 414         if (err == -EINPROGRESS ||
 415             (err == -EBUSY && (ahash_request_flags(req) &
 416                                CRYPTO_TFM_REQ_MAY_BACKLOG)))
 417                 return err;
 418
 419 out:
 420         ahash_restore_req(req, err);
 421         return err;
 422 }
 423
 424 static void ahash_def_finup_done1(struct crypto_async_request *req, int err)
 425 {
 426         struct ahash_request *areq = req->data;
 427
 428         if (err == -EINPROGRESS) {
 429                 ahash_notify_einprogress(areq);
 430                 return;
 431         }
 432
 433         areq->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
 434
 435         err = ahash_def_finup_finish1(areq, err);
 436         if (areq->priv)
 437                 return;
 438
 439         areq->base.complete(&areq->base, err);
 440 }
 441
 442 static int ahash_def_finup(struct ahash_request *req)
 443 {
 444         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 445         int err;
 446
 447         err = ahash_save_req(req, ahash_def_finup_done1);
 448         if (err)
 449                 return err;
 450
 451         err = tfm->update(req);
 452         if (err == -EINPROGRESS ||
 453             (err == -EBUSY && (ahash_request_flags(req) &
 454                                CRYPTO_TFM_REQ_MAY_BACKLOG)))
 455                 return err;
 456
 457         return ahash_def_finup_finish1(req, err);
 458 }
 459
 460 static int ahash_no_export(struct ahash_request *req, void *out)
 461 {
 462         return -ENOSYS;
 463 }
 464
 465 static int ahash_no_import(struct ahash_request *req, const void *in)
 466 {
 467         return -ENOSYS;
 468 }
 469
 470 static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
 471 {
 472         struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
 473         struct ahash_alg *alg = crypto_ahash_alg(hash);
 474
 475         hash->setkey = ahash_nosetkey;
 476         hash->has_setkey = false;
 477         hash->export = ahash_no_export;
 478         hash->import = ahash_no_import;
 479
 480         if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
 481                 return crypto_init_shash_ops_async(tfm);
 482
 483         hash->init = alg->init;
 484         hash->update = alg->update;
 485         hash->final = alg->final;
 486         hash->finup = alg->finup ?: ahash_def_finup;
 487         hash->digest = alg->digest;
 488
 489         if (alg->setkey) {
 490                 hash->setkey = alg->setkey;
 491                 hash->has_setkey = true;
 492         }
 493         if (alg->export)
 494                 hash->export = alg->export;
 495         if (alg->import)
 496                 hash->import = alg->import;
 497
 498         return 0;
 499 }
 500
 501 static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
 502 {
 503         if (alg->cra_type == &crypto_ahash_type)
 504                 return alg->cra_ctxsize;
 505
 506         return sizeof(struct crypto_shash *);
 507 }
 508
 509 #ifdef CONFIG_NET
 510 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 511 {
 512         struct crypto_report_hash rhash;
 513
 514         strncpy(rhash.type, "ahash", sizeof(rhash.type));
 515
 516         rhash.blocksize = alg->cra_blocksize;
 517         rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
 518
 519         if (nla_put(skb, CRYPTOCFGA_REPORT_HASH,
 520                     sizeof(struct crypto_report_hash), &rhash))
 521                 goto nla_put_failure;
 522         return 0;
 523
 524 nla_put_failure:
 525         return -EMSGSIZE;
 526 }
 527 #else
 528 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 529 {
 530         return -ENOSYS;
 531 }
 532 #endif
 533
 534 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 535         __attribute__ ((unused));
 536 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 537 {
 538         seq_printf(m, "type         : ahash\n");
 539         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 540                                              "yes" : "no");
 541         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 542         seq_printf(m, "digestsize   : %u\n",
 543                    __crypto_hash_alg_common(alg)->digestsize);
 544 }
 545
 546 const struct crypto_type crypto_ahash_type = {
 547         .extsize = crypto_ahash_extsize,
 548         .init_tfm = crypto_ahash_init_tfm,
 549 #ifdef CONFIG_PROC_FS
 550         .show = crypto_ahash_show,
 551 #endif
 552         .report = crypto_ahash_report,
 553         .maskclear = ~CRYPTO_ALG_TYPE_MASK,
 554         .maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
 555         .type = CRYPTO_ALG_TYPE_AHASH,
 556         .tfmsize = offsetof(struct crypto_ahash, base),
 557 };
 558 EXPORT_SYMBOL_GPL(crypto_ahash_type);
 559
 560 struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
 561                                         u32 mask)
 562 {
 563         return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
 564 }
 565 EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
 566
 567 static int ahash_prepare_alg(struct ahash_alg *alg)
 568 {
 569         struct crypto_alg *base = &alg->halg.base;
 570
 571         if (alg->halg.digestsize > PAGE_SIZE / 8 ||
 572             alg->halg.statesize > PAGE_SIZE / 8 ||
 573             alg->halg.statesize == 0)
 574                 return -EINVAL;
 575
 576         base->cra_type = &crypto_ahash_type;
 577         base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
 578         base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
 579
 580         return 0;
 581 }
 582
 583 int crypto_register_ahash(struct ahash_alg *alg)
 584 {
 585         struct crypto_alg *base = &alg->halg.base;
 586         int err;
 587
 588         err = ahash_prepare_alg(alg);
 589         if (err)
 590                 return err;
 591
 592         return crypto_register_alg(base);
 593 }
 594 EXPORT_SYMBOL_GPL(crypto_register_ahash);
 595
 596 int crypto_unregister_ahash(struct ahash_alg *alg)
 597 {
 598         return crypto_unregister_alg(&alg->halg.base);
 599 }
 600 EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
 601
 602 int ahash_register_instance(struct crypto_template *tmpl,
 603                             struct ahash_instance *inst)
 604 {
 605         int err;
 606
 607         err = ahash_prepare_alg(&inst->alg);
 608         if (err)
 609                 return err;
 610
 611         return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
 612 }
 613 EXPORT_SYMBOL_GPL(ahash_register_instance);
 614
 615 void ahash_free_instance(struct crypto_instance *inst)
 616 {
 617         crypto_drop_spawn(crypto_instance_ctx(inst));
 618         kfree(ahash_instance(inst));
 619 }
 620 EXPORT_SYMBOL_GPL(ahash_free_instance);
 621
 622 int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
 623                             struct hash_alg_common *alg,
 624                             struct crypto_instance *inst)
 625 {
 626         return crypto_init_spawn2(&spawn->base, &alg->base, inst,
 627                                   &crypto_ahash_type);
 628 }
 629 EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn);
 630
 631 struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
 632 {
 633         struct crypto_alg *alg;
 634
 635         alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask);
 636         return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg);
 637 }
 638 EXPORT_SYMBOL_GPL(ahash_attr_alg);
 639
 640 MODULE_LICENSE("GPL");
 641 MODULE_DESCRIPTION("Asynchronous cryptographic hash type");