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                 walk->entrylen = 0;
 136                 return 0;
 137         }
 138
 139         walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
 140         walk->sg = req->src;
 141         walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK;
 142
 143         return hash_walk_new_entry(walk);
 144 }
 145 EXPORT_SYMBOL_GPL(crypto_hash_walk_first);
 146
 147 int crypto_ahash_walk_first(struct ahash_request *req,
 148                             struct crypto_hash_walk *walk)
 149 {
 150         walk->total = req->nbytes;
 151
 152         if (!walk->total) {
 153                 walk->entrylen = 0;
 154                 return 0;
 155         }
 156
 157         walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
 158         walk->sg = req->src;
 159         walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK;
 160         walk->flags |= CRYPTO_ALG_ASYNC;
 161
 162         BUILD_BUG_ON(CRYPTO_TFM_REQ_MASK & CRYPTO_ALG_ASYNC);
 163
 164         return hash_walk_new_entry(walk);
 165 }
 166 EXPORT_SYMBOL_GPL(crypto_ahash_walk_first);
 167
 168 int crypto_hash_walk_first_compat(struct hash_desc *hdesc,
 169                                   struct crypto_hash_walk *walk,
 170                                   struct scatterlist *sg, unsigned int len)
 171 {
 172         walk->total = len;
 173
 174         if (!walk->total) {
 175                 walk->entrylen = 0;
 176                 return 0;
 177         }
 178
 179         walk->alignmask = crypto_hash_alignmask(hdesc->tfm);
 180         walk->sg = sg;
 181         walk->flags = hdesc->flags & CRYPTO_TFM_REQ_MASK;
 182
 183         return hash_walk_new_entry(walk);
 184 }
 185
 186 static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,
 187                                 unsigned int keylen)
 188 {
 189         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 190         int ret;
 191         u8 *buffer, *alignbuffer;
 192         unsigned long absize;
 193
 194         absize = keylen + alignmask;
 195         buffer = kmalloc(absize, GFP_KERNEL);
 196         if (!buffer)
 197                 return -ENOMEM;
 198
 199         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 200         memcpy(alignbuffer, key, keylen);
 201         ret = tfm->setkey(tfm, alignbuffer, keylen);
 202         kzfree(buffer);
 203         return ret;
 204 }
 205
 206 int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
 207                         unsigned int keylen)
 208 {
 209         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 210
 211         if ((unsigned long)key & alignmask)
 212                 return ahash_setkey_unaligned(tfm, key, keylen);
 213
 214         return tfm->setkey(tfm, key, keylen);
 215 }
 216 EXPORT_SYMBOL_GPL(crypto_ahash_setkey);
 217
 218 static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
 219                           unsigned int keylen)
 220 {
 221         return -ENOSYS;
 222 }
 223
 224 static inline unsigned int ahash_align_buffer_size(unsigned len,
 225                                                    unsigned long mask)
 226 {
 227         return len + (mask & ~(crypto_tfm_ctx_alignment() - 1));
 228 }
 229
 230 static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt)
 231 {
 232         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 233         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 234         unsigned int ds = crypto_ahash_digestsize(tfm);
 235         struct ahash_request_priv *priv;
 236
 237         priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
 238                        (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
 239                        GFP_KERNEL : GFP_ATOMIC);
 240         if (!priv)
 241                 return -ENOMEM;
 242
 243         /*
 244          * WARNING: Voodoo programming below!
 245          *
 246          * The code below is obscure and hard to understand, thus explanation
 247          * is necessary. See include/crypto/hash.h and include/linux/crypto.h
 248          * to understand the layout of structures used here!
 249          *
 250          * The code here will replace portions of the ORIGINAL request with
 251          * pointers to new code and buffers so the hashing operation can store
 252          * the result in aligned buffer. We will call the modified request
 253          * an ADJUSTED request.
 254          *
 255          * The newly mangled request will look as such:
 256          *
 257          * req {
 258          *   .result        = ADJUSTED[new aligned buffer]
 259          *   .base.complete = ADJUSTED[pointer to completion function]
 260          *   .base.data     = ADJUSTED[*req (pointer to self)]
 261          *   .priv          = ADJUSTED[new priv] {
 262          *           .result   = ORIGINAL(result)
 263          *           .complete = ORIGINAL(base.complete)
 264          *           .data     = ORIGINAL(base.data)
 265          *   }
 266          */
 267
 268         priv->result = req->result;
 269         priv->complete = req->base.complete;
 270         priv->data = req->base.data;
 271         /*
 272          * WARNING: We do not backup req->priv here! The req->priv
 273          *          is for internal use of the Crypto API and the
 274          *          user must _NOT_ _EVER_ depend on it's content!
 275          */
 276
 277         req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
 278         req->base.complete = cplt;
 279         req->base.data = req;
 280         req->priv = priv;
 281
 282         return 0;
 283 }
 284
 285 static void ahash_restore_req(struct ahash_request *req)
 286 {
 287         struct ahash_request_priv *priv = req->priv;
 288
 289         /* Restore the original crypto request. */
 290         req->result = priv->result;
 291         req->base.complete = priv->complete;
 292         req->base.data = priv->data;
 293         req->priv = NULL;
 294
 295         /* Free the req->priv.priv from the ADJUSTED request. */
 296         kzfree(priv);
 297 }
 298
 299 static void ahash_op_unaligned_finish(struct ahash_request *req, int err)
 300 {
 301         struct ahash_request_priv *priv = req->priv;
 302
 303         if (err == -EINPROGRESS)
 304                 return;
 305
 306         if (!err)
 307                 memcpy(priv->result, req->result,
 308                        crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
 309
 310         ahash_restore_req(req);
 311 }
 312
 313 static void ahash_op_unaligned_done(struct crypto_async_request *req, int err)
 314 {
 315         struct ahash_request *areq = req->data;
 316
 317         /*
 318          * Restore the original request, see ahash_op_unaligned() for what
 319          * goes where.
 320          *
 321          * The "struct ahash_request *req" here is in fact the "req.base"
 322          * from the ADJUSTED request from ahash_op_unaligned(), thus as it
 323          * is a pointer to self, it is also the ADJUSTED "req" .
 324          */
 325
 326         /* First copy req->result into req->priv.result */
 327         ahash_op_unaligned_finish(areq, err);
 328
 329         /* Complete the ORIGINAL request. */
 330         areq->base.complete(&areq->base, err);
 331 }
 332
 333 static int ahash_op_unaligned(struct ahash_request *req,
 334                               int (*op)(struct ahash_request *))
 335 {
 336         int err;
 337
 338         err = ahash_save_req(req, ahash_op_unaligned_done);
 339         if (err)
 340                 return err;
 341
 342         err = op(req);
 343         ahash_op_unaligned_finish(req, err);
 344
 345         return err;
 346 }
 347
 348 static int crypto_ahash_op(struct ahash_request *req,
 349                            int (*op)(struct ahash_request *))
 350 {
 351         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 352         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 353
 354         if ((unsigned long)req->result & alignmask)
 355                 return ahash_op_unaligned(req, op);
 356
 357         return op(req);
 358 }
 359
 360 int crypto_ahash_final(struct ahash_request *req)
 361 {
 362         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
 363 }
 364 EXPORT_SYMBOL_GPL(crypto_ahash_final);
 365
 366 int crypto_ahash_finup(struct ahash_request *req)
 367 {
 368         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
 369 }
 370 EXPORT_SYMBOL_GPL(crypto_ahash_finup);
 371
 372 int crypto_ahash_digest(struct ahash_request *req)
 373 {
 374         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->digest);
 375 }
 376 EXPORT_SYMBOL_GPL(crypto_ahash_digest);
 377
 378 static void ahash_def_finup_finish2(struct ahash_request *req, int err)
 379 {
 380         struct ahash_request_priv *priv = req->priv;
 381
 382         if (err == -EINPROGRESS)
 383                 return;
 384
 385         if (!err)
 386                 memcpy(priv->result, req->result,
 387                        crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
 388
 389         ahash_restore_req(req);
 390 }
 391
 392 static void ahash_def_finup_done2(struct crypto_async_request *req, int err)
 393 {
 394         struct ahash_request *areq = req->data;
 395
 396         ahash_def_finup_finish2(areq, err);
 397
 398         areq->base.complete(&areq->base, err);
 399 }
 400
 401 static int ahash_def_finup_finish1(struct ahash_request *req, int err)
 402 {
 403         if (err)
 404                 goto out;
 405
 406         req->base.complete = ahash_def_finup_done2;
 407         req->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
 408         err = crypto_ahash_reqtfm(req)->final(req);
 409
 410 out:
 411         ahash_def_finup_finish2(req, err);
 412         return err;
 413 }
 414
 415 static void ahash_def_finup_done1(struct crypto_async_request *req, int err)
 416 {
 417         struct ahash_request *areq = req->data;
 418
 419         err = ahash_def_finup_finish1(areq, err);
 420
 421         areq->base.complete(&areq->base, err);
 422 }
 423
 424 static int ahash_def_finup(struct ahash_request *req)
 425 {
 426         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 427         int err;
 428
 429         err = ahash_save_req(req, ahash_def_finup_done1);
 430         if (err)
 431                 return err;
 432
 433         err = tfm->update(req);
 434         return ahash_def_finup_finish1(req, err);
 435 }
 436
 437 static int ahash_no_export(struct ahash_request *req, void *out)
 438 {
 439         return -ENOSYS;
 440 }
 441
 442 static int ahash_no_import(struct ahash_request *req, const void *in)
 443 {
 444         return -ENOSYS;
 445 }
 446
 447 static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
 448 {
 449         struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
 450         struct ahash_alg *alg = crypto_ahash_alg(hash);
 451
 452         hash->setkey = ahash_nosetkey;
 453         hash->export = ahash_no_export;
 454         hash->import = ahash_no_import;
 455
 456         if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
 457                 return crypto_init_shash_ops_async(tfm);
 458
 459         hash->init = alg->init;
 460         hash->update = alg->update;
 461         hash->final = alg->final;
 462         hash->finup = alg->finup ?: ahash_def_finup;
 463         hash->digest = alg->digest;
 464
 465         if (alg->setkey)
 466                 hash->setkey = alg->setkey;
 467         if (alg->export)
 468                 hash->export = alg->export;
 469         if (alg->import)
 470                 hash->import = alg->import;
 471
 472         return 0;
 473 }
 474
 475 static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
 476 {
 477         if (alg->cra_type == &crypto_ahash_type)
 478                 return alg->cra_ctxsize;
 479
 480         return sizeof(struct crypto_shash *);
 481 }
 482
 483 #ifdef CONFIG_NET
 484 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 485 {
 486         struct crypto_report_hash rhash;
 487
 488         strncpy(rhash.type, "ahash", sizeof(rhash.type));
 489
 490         rhash.blocksize = alg->cra_blocksize;
 491         rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
 492
 493         if (nla_put(skb, CRYPTOCFGA_REPORT_HASH,
 494                     sizeof(struct crypto_report_hash), &rhash))
 495                 goto nla_put_failure;
 496         return 0;
 497
 498 nla_put_failure:
 499         return -EMSGSIZE;
 500 }
 501 #else
 502 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 503 {
 504         return -ENOSYS;
 505 }
 506 #endif
 507
 508 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 509         __attribute__ ((unused));
 510 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 511 {
 512         seq_printf(m, "type         : ahash\n");
 513         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 514                                              "yes" : "no");
 515         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 516         seq_printf(m, "digestsize   : %u\n",
 517                    __crypto_hash_alg_common(alg)->digestsize);
 518 }
 519
 520 const struct crypto_type crypto_ahash_type = {
 521         .extsize = crypto_ahash_extsize,
 522         .init_tfm = crypto_ahash_init_tfm,
 523 #ifdef CONFIG_PROC_FS
 524         .show = crypto_ahash_show,
 525 #endif
 526         .report = crypto_ahash_report,
 527         .maskclear = ~CRYPTO_ALG_TYPE_MASK,
 528         .maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
 529         .type = CRYPTO_ALG_TYPE_AHASH,
 530         .tfmsize = offsetof(struct crypto_ahash, base),
 531 };
 532 EXPORT_SYMBOL_GPL(crypto_ahash_type);
 533
 534 struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
 535                                         u32 mask)
 536 {
 537         return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
 538 }
 539 EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
 540
 541 static int ahash_prepare_alg(struct ahash_alg *alg)
 542 {
 543         struct crypto_alg *base = &alg->halg.base;
 544
 545         if (alg->halg.digestsize > PAGE_SIZE / 8 ||
 546             alg->halg.statesize > PAGE_SIZE / 8)
 547                 return -EINVAL;
 548
 549         base->cra_type = &crypto_ahash_type;
 550         base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
 551         base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
 552
 553         return 0;
 554 }
 555
 556 int crypto_register_ahash(struct ahash_alg *alg)
 557 {
 558         struct crypto_alg *base = &alg->halg.base;
 559         int err;
 560
 561         err = ahash_prepare_alg(alg);
 562         if (err)
 563                 return err;
 564
 565         return crypto_register_alg(base);
 566 }
 567 EXPORT_SYMBOL_GPL(crypto_register_ahash);
 568
 569 int crypto_unregister_ahash(struct ahash_alg *alg)
 570 {
 571         return crypto_unregister_alg(&alg->halg.base);
 572 }
 573 EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
 574
 575 int ahash_register_instance(struct crypto_template *tmpl,
 576                             struct ahash_instance *inst)
 577 {
 578         int err;
 579
 580         err = ahash_prepare_alg(&inst->alg);
 581         if (err)
 582                 return err;
 583
 584         return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
 585 }
 586 EXPORT_SYMBOL_GPL(ahash_register_instance);
 587
 588 void ahash_free_instance(struct crypto_instance *inst)
 589 {
 590         crypto_drop_spawn(crypto_instance_ctx(inst));
 591         kfree(ahash_instance(inst));
 592 }
 593 EXPORT_SYMBOL_GPL(ahash_free_instance);
 594
 595 int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
 596                             struct hash_alg_common *alg,
 597                             struct crypto_instance *inst)
 598 {
 599         return crypto_init_spawn2(&spawn->base, &alg->base, inst,
 600                                   &crypto_ahash_type);
 601 }
 602 EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn);
 603
 604 struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
 605 {
 606         struct crypto_alg *alg;
 607
 608         alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask);
 609         return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg);
 610 }
 611 EXPORT_SYMBOL_GPL(ahash_attr_alg);
 612
 613 MODULE_LICENSE("GPL");
 614 MODULE_DESCRIPTION("Asynchronous cryptographic hash type");