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         void *ubuf[] CRYPTO_MINALIGN_ATTR;
  35 };
  36
  37 static inline struct ahash_alg *crypto_ahash_alg(struct crypto_ahash *hash)
  38 {
  39         return container_of(crypto_hash_alg_common(hash), struct ahash_alg,
  40                             halg);
  41 }
  42
  43 static int hash_walk_next(struct crypto_hash_walk *walk)
  44 {
  45         unsigned int alignmask = walk->alignmask;
  46         unsigned int offset = walk->offset;
  47         unsigned int nbytes = min(walk->entrylen,
  48                                   ((unsigned int)(PAGE_SIZE)) - offset);
  49
  50         if (walk->flags & CRYPTO_ALG_ASYNC)
  51                 walk->data = kmap(walk->pg);
  52         else
  53                 walk->data = kmap_atomic(walk->pg);
  54         walk->data += offset;
  55
  56         if (offset & alignmask) {
  57                 unsigned int unaligned = alignmask + 1 - (offset & alignmask);
  58
  59                 if (nbytes > unaligned)
  60                         nbytes = unaligned;
  61         }
  62
  63         walk->entrylen -= nbytes;
  64         return nbytes;
  65 }
  66
  67 static int hash_walk_new_entry(struct crypto_hash_walk *walk)
  68 {
  69         struct scatterlist *sg;
  70
  71         sg = walk->sg;
  72         walk->pg = sg_page(sg);
  73         walk->offset = sg->offset;
  74         walk->entrylen = sg->length;
  75
  76         if (walk->entrylen > walk->total)
  77                 walk->entrylen = walk->total;
  78         walk->total -= walk->entrylen;
  79
  80         return hash_walk_next(walk);
  81 }
  82
  83 int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
  84 {
  85         unsigned int alignmask = walk->alignmask;
  86         unsigned int nbytes = walk->entrylen;
  87
  88         walk->data -= walk->offset;
  89
  90         if (nbytes && walk->offset & alignmask && !err) {
  91                 walk->offset = ALIGN(walk->offset, alignmask + 1);
  92                 walk->data += walk->offset;
  93
  94                 nbytes = min(nbytes,
  95                              ((unsigned int)(PAGE_SIZE)) - walk->offset);
  96                 walk->entrylen -= nbytes;
  97
  98                 return nbytes;
  99         }
 100
 101         if (walk->flags & CRYPTO_ALG_ASYNC)
 102                 kunmap(walk->pg);
 103         else {
 104                 kunmap_atomic(walk->data);
 105                 /*
 106                  * The may sleep test only makes sense for sync users.
 107                  * Async users don't need to sleep here anyway.
 108                  */
 109                 crypto_yield(walk->flags);
 110         }
 111
 112         if (err)
 113                 return err;
 114
 115         if (nbytes) {
 116                 walk->offset = 0;
 117                 walk->pg++;
 118                 return hash_walk_next(walk);
 119         }
 120
 121         if (!walk->total)
 122                 return 0;
 123
 124         walk->sg = sg_next(walk->sg);
 125
 126         return hash_walk_new_entry(walk);
 127 }
 128 EXPORT_SYMBOL_GPL(crypto_hash_walk_done);
 129
 130 int crypto_hash_walk_first(struct ahash_request *req,
 131                            struct crypto_hash_walk *walk)
 132 {
 133         walk->total = req->nbytes;
 134
 135         if (!walk->total) {
 136                 walk->entrylen = 0;
 137                 return 0;
 138         }
 139
 140         walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
 141         walk->sg = req->src;
 142         walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK;
 143
 144         return hash_walk_new_entry(walk);
 145 }
 146 EXPORT_SYMBOL_GPL(crypto_hash_walk_first);
 147
 148 int crypto_ahash_walk_first(struct ahash_request *req,
 149                             struct crypto_hash_walk *walk)
 150 {
 151         walk->total = req->nbytes;
 152
 153         if (!walk->total) {
 154                 walk->entrylen = 0;
 155                 return 0;
 156         }
 157
 158         walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
 159         walk->sg = req->src;
 160         walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK;
 161         walk->flags |= CRYPTO_ALG_ASYNC;
 162
 163         BUILD_BUG_ON(CRYPTO_TFM_REQ_MASK & CRYPTO_ALG_ASYNC);
 164
 165         return hash_walk_new_entry(walk);
 166 }
 167 EXPORT_SYMBOL_GPL(crypto_ahash_walk_first);
 168
 169 static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,
 170                                 unsigned int keylen)
 171 {
 172         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 173         int ret;
 174         u8 *buffer, *alignbuffer;
 175         unsigned long absize;
 176
 177         absize = keylen + alignmask;
 178         buffer = kmalloc(absize, GFP_KERNEL);
 179         if (!buffer)
 180                 return -ENOMEM;
 181
 182         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 183         memcpy(alignbuffer, key, keylen);
 184         ret = tfm->setkey(tfm, alignbuffer, keylen);
 185         kzfree(buffer);
 186         return ret;
 187 }
 188
 189 int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
 190                         unsigned int keylen)
 191 {
 192         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 193
 194         if ((unsigned long)key & alignmask)
 195                 return ahash_setkey_unaligned(tfm, key, keylen);
 196
 197         return tfm->setkey(tfm, key, keylen);
 198 }
 199 EXPORT_SYMBOL_GPL(crypto_ahash_setkey);
 200
 201 static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
 202                           unsigned int keylen)
 203 {
 204         return -ENOSYS;
 205 }
 206
 207 static inline unsigned int ahash_align_buffer_size(unsigned len,
 208                                                    unsigned long mask)
 209 {
 210         return len + (mask & ~(crypto_tfm_ctx_alignment() - 1));
 211 }
 212
 213 static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt)
 214 {
 215         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 216         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 217         unsigned int ds = crypto_ahash_digestsize(tfm);
 218         struct ahash_request_priv *priv;
 219
 220         priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
 221                        (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
 222                        GFP_KERNEL : GFP_ATOMIC);
 223         if (!priv)
 224                 return -ENOMEM;
 225
 226         /*
 227          * WARNING: Voodoo programming below!
 228          *
 229          * The code below is obscure and hard to understand, thus explanation
 230          * is necessary. See include/crypto/hash.h and include/linux/crypto.h
 231          * to understand the layout of structures used here!
 232          *
 233          * The code here will replace portions of the ORIGINAL request with
 234          * pointers to new code and buffers so the hashing operation can store
 235          * the result in aligned buffer. We will call the modified request
 236          * an ADJUSTED request.
 237          *
 238          * The newly mangled request will look as such:
 239          *
 240          * req {
 241          *   .result        = ADJUSTED[new aligned buffer]
 242          *   .base.complete = ADJUSTED[pointer to completion function]
 243          *   .base.data     = ADJUSTED[*req (pointer to self)]
 244          *   .priv          = ADJUSTED[new priv] {
 245          *           .result   = ORIGINAL(result)
 246          *           .complete = ORIGINAL(base.complete)
 247          *           .data     = ORIGINAL(base.data)
 248          *   }
 249          */
 250
 251         priv->result = req->result;
 252         priv->complete = req->base.complete;
 253         priv->data = req->base.data;
 254         /*
 255          * WARNING: We do not backup req->priv here! The req->priv
 256          *          is for internal use of the Crypto API and the
 257          *          user must _NOT_ _EVER_ depend on it's content!
 258          */
 259
 260         req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
 261         req->base.complete = cplt;
 262         req->base.data = req;
 263         req->priv = priv;
 264
 265         return 0;
 266 }
 267
 268 static void ahash_restore_req(struct ahash_request *req)
 269 {
 270         struct ahash_request_priv *priv = req->priv;
 271
 272         /* Restore the original crypto request. */
 273         req->result = priv->result;
 274         req->base.complete = priv->complete;
 275         req->base.data = priv->data;
 276         req->priv = NULL;
 277
 278         /* Free the req->priv.priv from the ADJUSTED request. */
 279         kzfree(priv);
 280 }
 281
 282 static void ahash_op_unaligned_finish(struct ahash_request *req, int err)
 283 {
 284         struct ahash_request_priv *priv = req->priv;
 285
 286         if (err == -EINPROGRESS)
 287                 return;
 288
 289         if (!err)
 290                 memcpy(priv->result, req->result,
 291                        crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
 292
 293         ahash_restore_req(req);
 294 }
 295
 296 static void ahash_op_unaligned_done(struct crypto_async_request *req, int err)
 297 {
 298         struct ahash_request *areq = req->data;
 299
 300         /*
 301          * Restore the original request, see ahash_op_unaligned() for what
 302          * goes where.
 303          *
 304          * The "struct ahash_request *req" here is in fact the "req.base"
 305          * from the ADJUSTED request from ahash_op_unaligned(), thus as it
 306          * is a pointer to self, it is also the ADJUSTED "req" .
 307          */
 308
 309         /* First copy req->result into req->priv.result */
 310         ahash_op_unaligned_finish(areq, err);
 311
 312         /* Complete the ORIGINAL request. */
 313         areq->base.complete(&areq->base, err);
 314 }
 315
 316 static int ahash_op_unaligned(struct ahash_request *req,
 317                               int (*op)(struct ahash_request *))
 318 {
 319         int err;
 320
 321         err = ahash_save_req(req, ahash_op_unaligned_done);
 322         if (err)
 323                 return err;
 324
 325         err = op(req);
 326         ahash_op_unaligned_finish(req, err);
 327
 328         return err;
 329 }
 330
 331 static int crypto_ahash_op(struct ahash_request *req,
 332                            int (*op)(struct ahash_request *))
 333 {
 334         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 335         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 336
 337         if ((unsigned long)req->result & alignmask)
 338                 return ahash_op_unaligned(req, op);
 339
 340         return op(req);
 341 }
 342
 343 int crypto_ahash_final(struct ahash_request *req)
 344 {
 345         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
 346 }
 347 EXPORT_SYMBOL_GPL(crypto_ahash_final);
 348
 349 int crypto_ahash_finup(struct ahash_request *req)
 350 {
 351         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
 352 }
 353 EXPORT_SYMBOL_GPL(crypto_ahash_finup);
 354
 355 int crypto_ahash_digest(struct ahash_request *req)
 356 {
 357         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->digest);
 358 }
 359 EXPORT_SYMBOL_GPL(crypto_ahash_digest);
 360
 361 static void ahash_def_finup_finish2(struct ahash_request *req, int err)
 362 {
 363         struct ahash_request_priv *priv = req->priv;
 364
 365         if (err == -EINPROGRESS)
 366                 return;
 367
 368         if (!err)
 369                 memcpy(priv->result, req->result,
 370                        crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
 371
 372         ahash_restore_req(req);
 373 }
 374
 375 static void ahash_def_finup_done2(struct crypto_async_request *req, int err)
 376 {
 377         struct ahash_request *areq = req->data;
 378
 379         ahash_def_finup_finish2(areq, err);
 380
 381         areq->base.complete(&areq->base, err);
 382 }
 383
 384 static int ahash_def_finup_finish1(struct ahash_request *req, int err)
 385 {
 386         if (err)
 387                 goto out;
 388
 389         req->base.complete = ahash_def_finup_done2;
 390         req->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
 391         err = crypto_ahash_reqtfm(req)->final(req);
 392
 393 out:
 394         ahash_def_finup_finish2(req, err);
 395         return err;
 396 }
 397
 398 static void ahash_def_finup_done1(struct crypto_async_request *req, int err)
 399 {
 400         struct ahash_request *areq = req->data;
 401
 402         err = ahash_def_finup_finish1(areq, err);
 403
 404         areq->base.complete(&areq->base, err);
 405 }
 406
 407 static int ahash_def_finup(struct ahash_request *req)
 408 {
 409         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 410         int err;
 411
 412         err = ahash_save_req(req, ahash_def_finup_done1);
 413         if (err)
 414                 return err;
 415
 416         err = tfm->update(req);
 417         return ahash_def_finup_finish1(req, err);
 418 }
 419
 420 static int ahash_no_export(struct ahash_request *req, void *out)
 421 {
 422         return -ENOSYS;
 423 }
 424
 425 static int ahash_no_import(struct ahash_request *req, const void *in)
 426 {
 427         return -ENOSYS;
 428 }
 429
 430 static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
 431 {
 432         struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
 433         struct ahash_alg *alg = crypto_ahash_alg(hash);
 434
 435         hash->setkey = ahash_nosetkey;
 436         hash->has_setkey = false;
 437         hash->export = ahash_no_export;
 438         hash->import = ahash_no_import;
 439
 440         if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
 441                 return crypto_init_shash_ops_async(tfm);
 442
 443         hash->init = alg->init;
 444         hash->update = alg->update;
 445         hash->final = alg->final;
 446         hash->finup = alg->finup ?: ahash_def_finup;
 447         hash->digest = alg->digest;
 448
 449         if (alg->setkey) {
 450                 hash->setkey = alg->setkey;
 451                 hash->has_setkey = true;
 452         }
 453         if (alg->export)
 454                 hash->export = alg->export;
 455         if (alg->import)
 456                 hash->import = alg->import;
 457
 458         return 0;
 459 }
 460
 461 static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
 462 {
 463         if (alg->cra_type == &crypto_ahash_type)
 464                 return alg->cra_ctxsize;
 465
 466         return sizeof(struct crypto_shash *);
 467 }
 468
 469 #ifdef CONFIG_NET
 470 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 471 {
 472         struct crypto_report_hash rhash;
 473
 474         strncpy(rhash.type, "ahash", sizeof(rhash.type));
 475
 476         rhash.blocksize = alg->cra_blocksize;
 477         rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
 478
 479         if (nla_put(skb, CRYPTOCFGA_REPORT_HASH,
 480                     sizeof(struct crypto_report_hash), &rhash))
 481                 goto nla_put_failure;
 482         return 0;
 483
 484 nla_put_failure:
 485         return -EMSGSIZE;
 486 }
 487 #else
 488 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 489 {
 490         return -ENOSYS;
 491 }
 492 #endif
 493
 494 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 495         __attribute__ ((unused));
 496 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 497 {
 498         seq_printf(m, "type         : ahash\n");
 499         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 500                                              "yes" : "no");
 501         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 502         seq_printf(m, "digestsize   : %u\n",
 503                    __crypto_hash_alg_common(alg)->digestsize);
 504 }
 505
 506 const struct crypto_type crypto_ahash_type = {
 507         .extsize = crypto_ahash_extsize,
 508         .init_tfm = crypto_ahash_init_tfm,
 509 #ifdef CONFIG_PROC_FS
 510         .show = crypto_ahash_show,
 511 #endif
 512         .report = crypto_ahash_report,
 513         .maskclear = ~CRYPTO_ALG_TYPE_MASK,
 514         .maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
 515         .type = CRYPTO_ALG_TYPE_AHASH,
 516         .tfmsize = offsetof(struct crypto_ahash, base),
 517 };
 518 EXPORT_SYMBOL_GPL(crypto_ahash_type);
 519
 520 struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
 521                                         u32 mask)
 522 {
 523         return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
 524 }
 525 EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
 526
 527 int crypto_has_ahash(const char *alg_name, u32 type, u32 mask)
 528 {
 529         return crypto_type_has_alg(alg_name, &crypto_ahash_type, type, mask);
 530 }
 531 EXPORT_SYMBOL_GPL(crypto_has_ahash);
 532
 533 static int ahash_prepare_alg(struct ahash_alg *alg)
 534 {
 535         struct crypto_alg *base = &alg->halg.base;
 536
 537         if (alg->halg.digestsize > PAGE_SIZE / 8 ||
 538             alg->halg.statesize > PAGE_SIZE / 8 ||
 539             alg->halg.statesize == 0)
 540                 return -EINVAL;
 541
 542         base->cra_type = &crypto_ahash_type;
 543         base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
 544         base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
 545
 546         return 0;
 547 }
 548
 549 int crypto_register_ahash(struct ahash_alg *alg)
 550 {
 551         struct crypto_alg *base = &alg->halg.base;
 552         int err;
 553
 554         err = ahash_prepare_alg(alg);
 555         if (err)
 556                 return err;
 557
 558         return crypto_register_alg(base);
 559 }
 560 EXPORT_SYMBOL_GPL(crypto_register_ahash);
 561
 562 int crypto_unregister_ahash(struct ahash_alg *alg)
 563 {
 564         return crypto_unregister_alg(&alg->halg.base);
 565 }
 566 EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
 567
 568 int ahash_register_instance(struct crypto_template *tmpl,
 569                             struct ahash_instance *inst)
 570 {
 571         int err;
 572
 573         err = ahash_prepare_alg(&inst->alg);
 574         if (err)
 575                 return err;
 576
 577         return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
 578 }
 579 EXPORT_SYMBOL_GPL(ahash_register_instance);
 580
 581 void ahash_free_instance(struct crypto_instance *inst)
 582 {
 583         crypto_drop_spawn(crypto_instance_ctx(inst));
 584         kfree(ahash_instance(inst));
 585 }
 586 EXPORT_SYMBOL_GPL(ahash_free_instance);
 587
 588 int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
 589                             struct hash_alg_common *alg,
 590                             struct crypto_instance *inst)
 591 {
 592         return crypto_init_spawn2(&spawn->base, &alg->base, inst,
 593                                   &crypto_ahash_type);
 594 }
 595 EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn);
 596
 597 struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
 598 {
 599         struct crypto_alg *alg;
 600
 601         alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask);
 602         return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg);
 603 }
 604 EXPORT_SYMBOL_GPL(ahash_attr_alg);
 605
 606 MODULE_LICENSE("GPL");
 607 MODULE_DESCRIPTION("Asynchronous cryptographic hash type");