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