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 int crypto_hash_walk_first_compat(struct hash_desc *hdesc,
 170                                   struct crypto_hash_walk *walk,
 171                                   struct scatterlist *sg, unsigned int len)
 172 {
 173         walk->total = len;
 174
 175         if (!walk->total) {
 176                 walk->entrylen = 0;
 177                 return 0;
 178         }
 179
 180         walk->alignmask = crypto_hash_alignmask(hdesc->tfm);
 181         walk->sg = sg;
 182         walk->flags = hdesc->flags & CRYPTO_TFM_REQ_MASK;
 183
 184         return hash_walk_new_entry(walk);
 185 }
 186
 187 static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,
 188                                 unsigned int keylen)
 189 {
 190         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 191         int ret;
 192         u8 *buffer, *alignbuffer;
 193         unsigned long absize;
 194
 195         absize = keylen + alignmask;
 196         buffer = kmalloc(absize, GFP_KERNEL);
 197         if (!buffer)
 198                 return -ENOMEM;
 199
 200         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 201         memcpy(alignbuffer, key, keylen);
 202         ret = tfm->setkey(tfm, alignbuffer, keylen);
 203         kzfree(buffer);
 204         return ret;
 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
 212         if ((unsigned long)key & alignmask)
 213                 return ahash_setkey_unaligned(tfm, key, keylen);
 214
 215         return tfm->setkey(tfm, key, keylen);
 216 }
 217 EXPORT_SYMBOL_GPL(crypto_ahash_setkey);
 218
 219 static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
 220                           unsigned int keylen)
 221 {
 222         return -ENOSYS;
 223 }
 224
 225 static inline unsigned int ahash_align_buffer_size(unsigned len,
 226                                                    unsigned long mask)
 227 {
 228         return len + (mask & ~(crypto_tfm_ctx_alignment() - 1));
 229 }
 230
 231 static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt)
 232 {
 233         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 234         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 235         unsigned int ds = crypto_ahash_digestsize(tfm);
 236         struct ahash_request_priv *priv;
 237
 238         priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
 239                        (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
 240                        GFP_KERNEL : GFP_ATOMIC);
 241         if (!priv)
 242                 return -ENOMEM;
 243
 244         /*
 245          * WARNING: Voodoo programming below!
 246          *
 247          * The code below is obscure and hard to understand, thus explanation
 248          * is necessary. See include/crypto/hash.h and include/linux/crypto.h
 249          * to understand the layout of structures used here!
 250          *
 251          * The code here will replace portions of the ORIGINAL request with
 252          * pointers to new code and buffers so the hashing operation can store
 253          * the result in aligned buffer. We will call the modified request
 254          * an ADJUSTED request.
 255          *
 256          * The newly mangled request will look as such:
 257          *
 258          * req {
 259          *   .result        = ADJUSTED[new aligned buffer]
 260          *   .base.complete = ADJUSTED[pointer to completion function]
 261          *   .base.data     = ADJUSTED[*req (pointer to self)]
 262          *   .priv          = ADJUSTED[new priv] {
 263          *           .result   = ORIGINAL(result)
 264          *           .complete = ORIGINAL(base.complete)
 265          *           .data     = ORIGINAL(base.data)
 266          *   }
 267          */
 268
 269         priv->result = req->result;
 270         priv->complete = req->base.complete;
 271         priv->data = req->base.data;
 272         /*
 273          * WARNING: We do not backup req->priv here! The req->priv
 274          *          is for internal use of the Crypto API and the
 275          *          user must _NOT_ _EVER_ depend on it's content!
 276          */
 277
 278         req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
 279         req->base.complete = cplt;
 280         req->base.data = req;
 281         req->priv = priv;
 282
 283         return 0;
 284 }
 285
 286 static void ahash_restore_req(struct ahash_request *req)
 287 {
 288         struct ahash_request_priv *priv = req->priv;
 289
 290         /* Restore the original crypto request. */
 291         req->result = priv->result;
 292         req->base.complete = priv->complete;
 293         req->base.data = priv->data;
 294         req->priv = NULL;
 295
 296         /* Free the req->priv.priv from the ADJUSTED request. */
 297         kzfree(priv);
 298 }
 299
 300 static void ahash_op_unaligned_finish(struct ahash_request *req, int err)
 301 {
 302         struct ahash_request_priv *priv = req->priv;
 303
 304         if (err == -EINPROGRESS)
 305                 return;
 306
 307         if (!err)
 308                 memcpy(priv->result, req->result,
 309                        crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
 310
 311         ahash_restore_req(req);
 312 }
 313
 314 static void ahash_op_unaligned_done(struct crypto_async_request *req, int err)
 315 {
 316         struct ahash_request *areq = req->data;
 317
 318         /*
 319          * Restore the original request, see ahash_op_unaligned() for what
 320          * goes where.
 321          *
 322          * The "struct ahash_request *req" here is in fact the "req.base"
 323          * from the ADJUSTED request from ahash_op_unaligned(), thus as it
 324          * is a pointer to self, it is also the ADJUSTED "req" .
 325          */
 326
 327         /* First copy req->result into req->priv.result */
 328         ahash_op_unaligned_finish(areq, err);
 329
 330         /* Complete the ORIGINAL request. */
 331         areq->base.complete(&areq->base, err);
 332 }
 333
 334 static int ahash_op_unaligned(struct ahash_request *req,
 335                               int (*op)(struct ahash_request *))
 336 {
 337         int err;
 338
 339         err = ahash_save_req(req, ahash_op_unaligned_done);
 340         if (err)
 341                 return err;
 342
 343         err = op(req);
 344         ahash_op_unaligned_finish(req, err);
 345
 346         return err;
 347 }
 348
 349 static int crypto_ahash_op(struct ahash_request *req,
 350                            int (*op)(struct ahash_request *))
 351 {
 352         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 353         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 354
 355         if ((unsigned long)req->result & alignmask)
 356                 return ahash_op_unaligned(req, op);
 357
 358         return op(req);
 359 }
 360
 361 int crypto_ahash_final(struct ahash_request *req)
 362 {
 363         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
 364 }
 365 EXPORT_SYMBOL_GPL(crypto_ahash_final);
 366
 367 int crypto_ahash_finup(struct ahash_request *req)
 368 {
 369         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
 370 }
 371 EXPORT_SYMBOL_GPL(crypto_ahash_finup);
 372
 373 int crypto_ahash_digest(struct ahash_request *req)
 374 {
 375         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->digest);
 376 }
 377 EXPORT_SYMBOL_GPL(crypto_ahash_digest);
 378
 379 static void ahash_def_finup_finish2(struct ahash_request *req, int err)
 380 {
 381         struct ahash_request_priv *priv = req->priv;
 382
 383         if (err == -EINPROGRESS)
 384                 return;
 385
 386         if (!err)
 387                 memcpy(priv->result, req->result,
 388                        crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
 389
 390         ahash_restore_req(req);
 391 }
 392
 393 static void ahash_def_finup_done2(struct crypto_async_request *req, int err)
 394 {
 395         struct ahash_request *areq = req->data;
 396
 397         ahash_def_finup_finish2(areq, err);
 398
 399         areq->base.complete(&areq->base, err);
 400 }
 401
 402 static int ahash_def_finup_finish1(struct ahash_request *req, int err)
 403 {
 404         if (err)
 405                 goto out;
 406
 407         req->base.complete = ahash_def_finup_done2;
 408         req->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
 409         err = crypto_ahash_reqtfm(req)->final(req);
 410
 411 out:
 412         ahash_def_finup_finish2(req, err);
 413         return err;
 414 }
 415
 416 static void ahash_def_finup_done1(struct crypto_async_request *req, int err)
 417 {
 418         struct ahash_request *areq = req->data;
 419
 420         err = ahash_def_finup_finish1(areq, err);
 421
 422         areq->base.complete(&areq->base, err);
 423 }
 424
 425 static int ahash_def_finup(struct ahash_request *req)
 426 {
 427         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 428         int err;
 429
 430         err = ahash_save_req(req, ahash_def_finup_done1);
 431         if (err)
 432                 return err;
 433
 434         err = tfm->update(req);
 435         return ahash_def_finup_finish1(req, err);
 436 }
 437
 438 static int ahash_no_export(struct ahash_request *req, void *out)
 439 {
 440         return -ENOSYS;
 441 }
 442
 443 static int ahash_no_import(struct ahash_request *req, const void *in)
 444 {
 445         return -ENOSYS;
 446 }
 447
 448 static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
 449 {
 450         struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
 451         struct ahash_alg *alg = crypto_ahash_alg(hash);
 452
 453         hash->setkey = ahash_nosetkey;
 454         hash->has_setkey = false;
 455         hash->export = ahash_no_export;
 456         hash->import = ahash_no_import;
 457
 458         if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
 459                 return crypto_init_shash_ops_async(tfm);
 460
 461         hash->init = alg->init;
 462         hash->update = alg->update;
 463         hash->final = alg->final;
 464         hash->finup = alg->finup ?: ahash_def_finup;
 465         hash->digest = alg->digest;
 466
 467         if (alg->setkey) {
 468                 hash->setkey = alg->setkey;
 469                 hash->has_setkey = true;
 470         }
 471         if (alg->export)
 472                 hash->export = alg->export;
 473         if (alg->import)
 474                 hash->import = alg->import;
 475
 476         return 0;
 477 }
 478
 479 static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
 480 {
 481         if (alg->cra_type == &crypto_ahash_type)
 482                 return alg->cra_ctxsize;
 483
 484         return sizeof(struct crypto_shash *);
 485 }
 486
 487 #ifdef CONFIG_NET
 488 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 489 {
 490         struct crypto_report_hash rhash;
 491
 492         strncpy(rhash.type, "ahash", sizeof(rhash.type));
 493
 494         rhash.blocksize = alg->cra_blocksize;
 495         rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
 496
 497         if (nla_put(skb, CRYPTOCFGA_REPORT_HASH,
 498                     sizeof(struct crypto_report_hash), &rhash))
 499                 goto nla_put_failure;
 500         return 0;
 501
 502 nla_put_failure:
 503         return -EMSGSIZE;
 504 }
 505 #else
 506 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 507 {
 508         return -ENOSYS;
 509 }
 510 #endif
 511
 512 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 513         __attribute__ ((unused));
 514 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 515 {
 516         seq_printf(m, "type         : ahash\n");
 517         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 518                                              "yes" : "no");
 519         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 520         seq_printf(m, "digestsize   : %u\n",
 521                    __crypto_hash_alg_common(alg)->digestsize);
 522 }
 523
 524 const struct crypto_type crypto_ahash_type = {
 525         .extsize = crypto_ahash_extsize,
 526         .init_tfm = crypto_ahash_init_tfm,
 527 #ifdef CONFIG_PROC_FS
 528         .show = crypto_ahash_show,
 529 #endif
 530         .report = crypto_ahash_report,
 531         .maskclear = ~CRYPTO_ALG_TYPE_MASK,
 532         .maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
 533         .type = CRYPTO_ALG_TYPE_AHASH,
 534         .tfmsize = offsetof(struct crypto_ahash, base),
 535 };
 536 EXPORT_SYMBOL_GPL(crypto_ahash_type);
 537
 538 struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
 539                                         u32 mask)
 540 {
 541         return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
 542 }
 543 EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
 544
 545 static int ahash_prepare_alg(struct ahash_alg *alg)
 546 {
 547         struct crypto_alg *base = &alg->halg.base;
 548
 549         if (alg->halg.digestsize > PAGE_SIZE / 8 ||
 550             alg->halg.statesize > PAGE_SIZE / 8 ||
 551             alg->halg.statesize == 0)
 552                 return -EINVAL;
 553
 554         base->cra_type = &crypto_ahash_type;
 555         base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
 556         base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
 557
 558         return 0;
 559 }
 560
 561 int crypto_register_ahash(struct ahash_alg *alg)
 562 {
 563         struct crypto_alg *base = &alg->halg.base;
 564         int err;
 565
 566         err = ahash_prepare_alg(alg);
 567         if (err)
 568                 return err;
 569
 570         return crypto_register_alg(base);
 571 }
 572 EXPORT_SYMBOL_GPL(crypto_register_ahash);
 573
 574 int crypto_unregister_ahash(struct ahash_alg *alg)
 575 {
 576         return crypto_unregister_alg(&alg->halg.base);
 577 }
 578 EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
 579
 580 int ahash_register_instance(struct crypto_template *tmpl,
 581                             struct ahash_instance *inst)
 582 {
 583         int err;
 584
 585         err = ahash_prepare_alg(&inst->alg);
 586         if (err)
 587                 return err;
 588
 589         return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
 590 }
 591 EXPORT_SYMBOL_GPL(ahash_register_instance);
 592
 593 void ahash_free_instance(struct crypto_instance *inst)
 594 {
 595         crypto_drop_spawn(crypto_instance_ctx(inst));
 596         kfree(ahash_instance(inst));
 597 }
 598 EXPORT_SYMBOL_GPL(ahash_free_instance);
 599
 600 int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
 601                             struct hash_alg_common *alg,
 602                             struct crypto_instance *inst)
 603 {
 604         return crypto_init_spawn2(&spawn->base, &alg->base, inst,
 605                                   &crypto_ahash_type);
 606 }
 607 EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn);
 608
 609 struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
 610 {
 611         struct crypto_alg *alg;
 612
 613         alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask);
 614         return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg);
 615 }
 616 EXPORT_SYMBOL_GPL(ahash_attr_alg);
 617
 618 MODULE_LICENSE("GPL");
 619 MODULE_DESCRIPTION("Asynchronous cryptographic hash type");