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         u32 flags;
  35         void *ubuf[] CRYPTO_MINALIGN_ATTR;
  36 };
  37
  38 static inline struct ahash_alg *crypto_ahash_alg(struct crypto_ahash *hash)
  39 {
  40         return container_of(crypto_hash_alg_common(hash), struct ahash_alg,
  41                             halg);
  42 }
  43
  44 static int hash_walk_next(struct crypto_hash_walk *walk)
  45 {
  46         unsigned int alignmask = walk->alignmask;
  47         unsigned int offset = walk->offset;
  48         unsigned int nbytes = min(walk->entrylen,
  49                                   ((unsigned int)(PAGE_SIZE)) - offset);
  50
  51         if (walk->flags & CRYPTO_ALG_ASYNC)
  52                 walk->data = kmap(walk->pg);
  53         else
  54                 walk->data = kmap_atomic(walk->pg);
  55         walk->data += offset;
  56
  57         if (offset & alignmask) {
  58                 unsigned int unaligned = alignmask + 1 - (offset & alignmask);
  59
  60                 if (nbytes > unaligned)
  61                         nbytes = unaligned;
  62         }
  63
  64         walk->entrylen -= nbytes;
  65         return nbytes;
  66 }
  67
  68 static int hash_walk_new_entry(struct crypto_hash_walk *walk)
  69 {
  70         struct scatterlist *sg;
  71
  72         sg = walk->sg;
  73         walk->offset = sg->offset;
  74         walk->pg = sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
  75         walk->offset = offset_in_page(walk->offset);
  76         walk->entrylen = sg->length;
  77
  78         if (walk->entrylen > walk->total)
  79                 walk->entrylen = walk->total;
  80         walk->total -= walk->entrylen;
  81
  82         return hash_walk_next(walk);
  83 }
  84
  85 int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
  86 {
  87         unsigned int alignmask = walk->alignmask;
  88         unsigned int nbytes = walk->entrylen;
  89
  90         walk->data -= walk->offset;
  91
  92         if (nbytes && walk->offset & alignmask && !err) {
  93                 walk->offset = ALIGN(walk->offset, alignmask + 1);
  94                 walk->data += walk->offset;
  95
  96                 nbytes = min(nbytes,
  97                              ((unsigned int)(PAGE_SIZE)) - walk->offset);
  98                 walk->entrylen -= nbytes;
  99
 100                 return nbytes;
 101         }
 102
 103         if (walk->flags & CRYPTO_ALG_ASYNC)
 104                 kunmap(walk->pg);
 105         else {
 106                 kunmap_atomic(walk->data);
 107                 /*
 108                  * The may sleep test only makes sense for sync users.
 109                  * Async users don't need to sleep here anyway.
 110                  */
 111                 crypto_yield(walk->flags);
 112         }
 113
 114         if (err)
 115                 return err;
 116
 117         if (nbytes) {
 118                 walk->offset = 0;
 119                 walk->pg++;
 120                 return hash_walk_next(walk);
 121         }
 122
 123         if (!walk->total)
 124                 return 0;
 125
 126         walk->sg = sg_next(walk->sg);
 127
 128         return hash_walk_new_entry(walk);
 129 }
 130 EXPORT_SYMBOL_GPL(crypto_hash_walk_done);
 131
 132 int crypto_hash_walk_first(struct ahash_request *req,
 133                            struct crypto_hash_walk *walk)
 134 {
 135         walk->total = req->nbytes;
 136
 137         if (!walk->total) {
 138                 walk->entrylen = 0;
 139                 return 0;
 140         }
 141
 142         walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
 143         walk->sg = req->src;
 144         walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK;
 145
 146         return hash_walk_new_entry(walk);
 147 }
 148 EXPORT_SYMBOL_GPL(crypto_hash_walk_first);
 149
 150 int crypto_ahash_walk_first(struct ahash_request *req,
 151                             struct crypto_hash_walk *walk)
 152 {
 153         walk->total = req->nbytes;
 154
 155         if (!walk->total) {
 156                 walk->entrylen = 0;
 157                 return 0;
 158         }
 159
 160         walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
 161         walk->sg = req->src;
 162         walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK;
 163         walk->flags |= CRYPTO_ALG_ASYNC;
 164
 165         BUILD_BUG_ON(CRYPTO_TFM_REQ_MASK & CRYPTO_ALG_ASYNC);
 166
 167         return hash_walk_new_entry(walk);
 168 }
 169 EXPORT_SYMBOL_GPL(crypto_ahash_walk_first);
 170
 171 static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,
 172                                 unsigned int keylen)
 173 {
 174         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 175         int ret;
 176         u8 *buffer, *alignbuffer;
 177         unsigned long absize;
 178
 179         absize = keylen + alignmask;
 180         buffer = kmalloc(absize, GFP_KERNEL);
 181         if (!buffer)
 182                 return -ENOMEM;
 183
 184         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 185         memcpy(alignbuffer, key, keylen);
 186         ret = tfm->setkey(tfm, alignbuffer, keylen);
 187         kzfree(buffer);
 188         return ret;
 189 }
 190
 191 int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
 192                         unsigned int keylen)
 193 {
 194         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 195
 196         if ((unsigned long)key & alignmask)
 197                 return ahash_setkey_unaligned(tfm, key, keylen);
 198
 199         return tfm->setkey(tfm, key, keylen);
 200 }
 201 EXPORT_SYMBOL_GPL(crypto_ahash_setkey);
 202
 203 static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
 204                           unsigned int keylen)
 205 {
 206         return -ENOSYS;
 207 }
 208
 209 static inline unsigned int ahash_align_buffer_size(unsigned len,
 210                                                    unsigned long mask)
 211 {
 212         return len + (mask & ~(crypto_tfm_ctx_alignment() - 1));
 213 }
 214
 215 static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt)
 216 {
 217         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 218         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 219         unsigned int ds = crypto_ahash_digestsize(tfm);
 220         struct ahash_request_priv *priv;
 221
 222         priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
 223                        (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
 224                        GFP_KERNEL : GFP_ATOMIC);
 225         if (!priv)
 226                 return -ENOMEM;
 227
 228         /*
 229          * WARNING: Voodoo programming below!
 230          *
 231          * The code below is obscure and hard to understand, thus explanation
 232          * is necessary. See include/crypto/hash.h and include/linux/crypto.h
 233          * to understand the layout of structures used here!
 234          *
 235          * The code here will replace portions of the ORIGINAL request with
 236          * pointers to new code and buffers so the hashing operation can store
 237          * the result in aligned buffer. We will call the modified request
 238          * an ADJUSTED request.
 239          *
 240          * The newly mangled request will look as such:
 241          *
 242          * req {
 243          *   .result        = ADJUSTED[new aligned buffer]
 244          *   .base.complete = ADJUSTED[pointer to completion function]
 245          *   .base.data     = ADJUSTED[*req (pointer to self)]
 246          *   .priv          = ADJUSTED[new priv] {
 247          *           .result   = ORIGINAL(result)
 248          *           .complete = ORIGINAL(base.complete)
 249          *           .data     = ORIGINAL(base.data)
 250          *   }
 251          */
 252
 253         priv->result = req->result;
 254         priv->complete = req->base.complete;
 255         priv->data = req->base.data;
 256         priv->flags = req->base.flags;
 257
 258         /*
 259          * WARNING: We do not backup req->priv here! The req->priv
 260          *          is for internal use of the Crypto API and the
 261          *          user must _NOT_ _EVER_ depend on it's content!
 262          */
 263
 264         req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
 265         req->base.complete = cplt;
 266         req->base.data = req;
 267         req->priv = priv;
 268
 269         return 0;
 270 }
 271
 272 static void ahash_restore_req(struct ahash_request *req, int err)
 273 {
 274         struct ahash_request_priv *priv = req->priv;
 275
 276         if (!err)
 277                 memcpy(priv->result, req->result,
 278                        crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
 279
 280         /* Restore the original crypto request. */
 281         req->result = priv->result;
 282
 283         ahash_request_set_callback(req, priv->flags,
 284                                    priv->complete, priv->data);
 285         req->priv = NULL;
 286
 287         /* Free the req->priv.priv from the ADJUSTED request. */
 288         kzfree(priv);
 289 }
 290
 291 static void ahash_notify_einprogress(struct ahash_request *req)
 292 {
 293         struct ahash_request_priv *priv = req->priv;
 294         struct crypto_async_request oreq;
 295
 296         oreq.data = priv->data;
 297
 298         priv->complete(&oreq, -EINPROGRESS);
 299 }
 300
 301 static void ahash_op_unaligned_done(struct crypto_async_request *req, int err)
 302 {
 303         struct ahash_request *areq = req->data;
 304
 305         if (err == -EINPROGRESS) {
 306                 ahash_notify_einprogress(areq);
 307                 return;
 308         }
 309
 310         /*
 311          * Restore the original request, see ahash_op_unaligned() for what
 312          * goes where.
 313          *
 314          * The "struct ahash_request *req" here is in fact the "req.base"
 315          * from the ADJUSTED request from ahash_op_unaligned(), thus as it
 316          * is a pointer to self, it is also the ADJUSTED "req" .
 317          */
 318
 319         /* First copy req->result into req->priv.result */
 320         ahash_restore_req(areq, err);
 321
 322         /* Complete the ORIGINAL request. */
 323         areq->base.complete(&areq->base, err);
 324 }
 325
 326 static int ahash_op_unaligned(struct ahash_request *req,
 327                               int (*op)(struct ahash_request *))
 328 {
 329         int err;
 330
 331         err = ahash_save_req(req, ahash_op_unaligned_done);
 332         if (err)
 333                 return err;
 334
 335         err = op(req);
 336         if (err == -EINPROGRESS ||
 337             (err == -EBUSY && (ahash_request_flags(req) &
 338                                CRYPTO_TFM_REQ_MAY_BACKLOG)))
 339                 return err;
 340
 341         ahash_restore_req(req, err);
 342
 343         return err;
 344 }
 345
 346 static int crypto_ahash_op(struct ahash_request *req,
 347                            int (*op)(struct ahash_request *))
 348 {
 349         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 350         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 351
 352         if ((unsigned long)req->result & alignmask)
 353                 return ahash_op_unaligned(req, op);
 354
 355         return op(req);
 356 }
 357
 358 int crypto_ahash_final(struct ahash_request *req)
 359 {
 360         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
 361 }
 362 EXPORT_SYMBOL_GPL(crypto_ahash_final);
 363
 364 int crypto_ahash_finup(struct ahash_request *req)
 365 {
 366         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
 367 }
 368 EXPORT_SYMBOL_GPL(crypto_ahash_finup);
 369
 370 int crypto_ahash_digest(struct ahash_request *req)
 371 {
 372         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->digest);
 373 }
 374 EXPORT_SYMBOL_GPL(crypto_ahash_digest);
 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         if (err == -EINPROGRESS)
 381                 return;
 382
 383         ahash_restore_req(areq, err);
 384
 385         areq->base.complete(&areq->base, err);
 386 }
 387
 388 static int ahash_def_finup_finish1(struct ahash_request *req, int err)
 389 {
 390         if (err)
 391                 goto out;
 392
 393         req->base.complete = ahash_def_finup_done2;
 394
 395         err = crypto_ahash_reqtfm(req)->final(req);
 396         if (err == -EINPROGRESS ||
 397             (err == -EBUSY && (ahash_request_flags(req) &
 398                                CRYPTO_TFM_REQ_MAY_BACKLOG)))
 399                 return err;
 400
 401 out:
 402         ahash_restore_req(req, err);
 403         return err;
 404 }
 405
 406 static void ahash_def_finup_done1(struct crypto_async_request *req, int err)
 407 {
 408         struct ahash_request *areq = req->data;
 409
 410         if (err == -EINPROGRESS) {
 411                 ahash_notify_einprogress(areq);
 412                 return;
 413         }
 414
 415         areq->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
 416
 417         err = ahash_def_finup_finish1(areq, err);
 418         if (areq->priv)
 419                 return;
 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         if (err == -EINPROGRESS ||
 435             (err == -EBUSY && (ahash_request_flags(req) &
 436                                CRYPTO_TFM_REQ_MAY_BACKLOG)))
 437                 return err;
 438
 439         return ahash_def_finup_finish1(req, err);
 440 }
 441
 442 static int ahash_no_export(struct ahash_request *req, void *out)
 443 {
 444         return -ENOSYS;
 445 }
 446
 447 static int ahash_no_import(struct ahash_request *req, const void *in)
 448 {
 449         return -ENOSYS;
 450 }
 451
 452 static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
 453 {
 454         struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
 455         struct ahash_alg *alg = crypto_ahash_alg(hash);
 456
 457         hash->setkey = ahash_nosetkey;
 458         hash->has_setkey = false;
 459         hash->export = ahash_no_export;
 460         hash->import = ahash_no_import;
 461
 462         if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
 463                 return crypto_init_shash_ops_async(tfm);
 464
 465         hash->init = alg->init;
 466         hash->update = alg->update;
 467         hash->final = alg->final;
 468         hash->finup = alg->finup ?: ahash_def_finup;
 469         hash->digest = alg->digest;
 470
 471         if (alg->setkey) {
 472                 hash->setkey = alg->setkey;
 473                 hash->has_setkey = true;
 474         }
 475         if (alg->export)
 476                 hash->export = alg->export;
 477         if (alg->import)
 478                 hash->import = alg->import;
 479
 480         return 0;
 481 }
 482
 483 static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
 484 {
 485         if (alg->cra_type != &crypto_ahash_type)
 486                 return sizeof(struct crypto_shash *);
 487
 488         return crypto_alg_extsize(alg);
 489 }
 490
 491 #ifdef CONFIG_NET
 492 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 493 {
 494         struct crypto_report_hash rhash;
 495
 496         strncpy(rhash.type, "ahash", sizeof(rhash.type));
 497
 498         rhash.blocksize = alg->cra_blocksize;
 499         rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
 500
 501         if (nla_put(skb, CRYPTOCFGA_REPORT_HASH,
 502                     sizeof(struct crypto_report_hash), &rhash))
 503                 goto nla_put_failure;
 504         return 0;
 505
 506 nla_put_failure:
 507         return -EMSGSIZE;
 508 }
 509 #else
 510 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 511 {
 512         return -ENOSYS;
 513 }
 514 #endif
 515
 516 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 517         __attribute__ ((unused));
 518 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 519 {
 520         seq_printf(m, "type         : ahash\n");
 521         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 522                                              "yes" : "no");
 523         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 524         seq_printf(m, "digestsize   : %u\n",
 525                    __crypto_hash_alg_common(alg)->digestsize);
 526 }
 527
 528 const struct crypto_type crypto_ahash_type = {
 529         .extsize = crypto_ahash_extsize,
 530         .init_tfm = crypto_ahash_init_tfm,
 531 #ifdef CONFIG_PROC_FS
 532         .show = crypto_ahash_show,
 533 #endif
 534         .report = crypto_ahash_report,
 535         .maskclear = ~CRYPTO_ALG_TYPE_MASK,
 536         .maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
 537         .type = CRYPTO_ALG_TYPE_AHASH,
 538         .tfmsize = offsetof(struct crypto_ahash, base),
 539 };
 540 EXPORT_SYMBOL_GPL(crypto_ahash_type);
 541
 542 struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
 543                                         u32 mask)
 544 {
 545         return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
 546 }
 547 EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
 548
 549 int crypto_has_ahash(const char *alg_name, u32 type, u32 mask)
 550 {
 551         return crypto_type_has_alg(alg_name, &crypto_ahash_type, type, mask);
 552 }
 553 EXPORT_SYMBOL_GPL(crypto_has_ahash);
 554
 555 static int ahash_prepare_alg(struct ahash_alg *alg)
 556 {
 557         struct crypto_alg *base = &alg->halg.base;
 558
 559         if (alg->halg.digestsize > PAGE_SIZE / 8 ||
 560             alg->halg.statesize > PAGE_SIZE / 8 ||
 561             alg->halg.statesize == 0)
 562                 return -EINVAL;
 563
 564         base->cra_type = &crypto_ahash_type;
 565         base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
 566         base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
 567
 568         return 0;
 569 }
 570
 571 int crypto_register_ahash(struct ahash_alg *alg)
 572 {
 573         struct crypto_alg *base = &alg->halg.base;
 574         int err;
 575
 576         err = ahash_prepare_alg(alg);
 577         if (err)
 578                 return err;
 579
 580         return crypto_register_alg(base);
 581 }
 582 EXPORT_SYMBOL_GPL(crypto_register_ahash);
 583
 584 int crypto_unregister_ahash(struct ahash_alg *alg)
 585 {
 586         return crypto_unregister_alg(&alg->halg.base);
 587 }
 588 EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
 589
 590 int ahash_register_instance(struct crypto_template *tmpl,
 591                             struct ahash_instance *inst)
 592 {
 593         int err;
 594
 595         err = ahash_prepare_alg(&inst->alg);
 596         if (err)
 597                 return err;
 598
 599         return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
 600 }
 601 EXPORT_SYMBOL_GPL(ahash_register_instance);
 602
 603 void ahash_free_instance(struct crypto_instance *inst)
 604 {
 605         crypto_drop_spawn(crypto_instance_ctx(inst));
 606         kfree(ahash_instance(inst));
 607 }
 608 EXPORT_SYMBOL_GPL(ahash_free_instance);
 609
 610 int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
 611                             struct hash_alg_common *alg,
 612                             struct crypto_instance *inst)
 613 {
 614         return crypto_init_spawn2(&spawn->base, &alg->base, inst,
 615                                   &crypto_ahash_type);
 616 }
 617 EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn);
 618
 619 struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
 620 {
 621         struct crypto_alg *alg;
 622
 623         alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask);
 624         return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg);
 625 }
 626 EXPORT_SYMBOL_GPL(ahash_attr_alg);
 627
 628 MODULE_LICENSE("GPL");
 629 MODULE_DESCRIPTION("Asynchronous cryptographic hash type");