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