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 <linux/compiler.h>
  27 #include <net/netlink.h>
  28
  29 #include "internal.h"
  30
  31 struct ahash_request_priv {
  32         crypto_completion_t complete;
  33         void *data;
  34         u8 *result;
  35         u32 flags;
  36         void *ubuf[] CRYPTO_MINALIGN_ATTR;
  37 };
  38
  39 static inline struct ahash_alg *crypto_ahash_alg(struct crypto_ahash *hash)
  40 {
  41         return container_of(crypto_hash_alg_common(hash), struct ahash_alg,
  42                             halg);
  43 }
  44
  45 static int hash_walk_next(struct crypto_hash_walk *walk)
  46 {
  47         unsigned int alignmask = walk->alignmask;
  48         unsigned int offset = walk->offset;
  49         unsigned int nbytes = min(walk->entrylen,
  50                                   ((unsigned int)(PAGE_SIZE)) - offset);
  51
  52         if (walk->flags & CRYPTO_ALG_ASYNC)
  53                 walk->data = kmap(walk->pg);
  54         else
  55                 walk->data = kmap_atomic(walk->pg);
  56         walk->data += offset;
  57
  58         if (offset & alignmask) {
  59                 unsigned int unaligned = alignmask + 1 - (offset & alignmask);
  60
  61                 if (nbytes > unaligned)
  62                         nbytes = unaligned;
  63         }
  64
  65         walk->entrylen -= nbytes;
  66         return nbytes;
  67 }
  68
  69 static int hash_walk_new_entry(struct crypto_hash_walk *walk)
  70 {
  71         struct scatterlist *sg;
  72
  73         sg = walk->sg;
  74         walk->offset = sg->offset;
  75         walk->pg = sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
  76         walk->offset = offset_in_page(walk->offset);
  77         walk->entrylen = sg->length;
  78
  79         if (walk->entrylen > walk->total)
  80                 walk->entrylen = walk->total;
  81         walk->total -= walk->entrylen;
  82
  83         return hash_walk_next(walk);
  84 }
  85
  86 int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
  87 {
  88         unsigned int alignmask = walk->alignmask;
  89         unsigned int nbytes = walk->entrylen;
  90
  91         walk->data -= walk->offset;
  92
  93         if (nbytes && walk->offset & alignmask && !err) {
  94                 walk->offset = ALIGN(walk->offset, alignmask + 1);
  95                 walk->data += walk->offset;
  96
  97                 nbytes = min(nbytes,
  98                              ((unsigned int)(PAGE_SIZE)) - walk->offset);
  99                 walk->entrylen -= nbytes;
 100
 101                 return nbytes;
 102         }
 103
 104         if (walk->flags & CRYPTO_ALG_ASYNC)
 105                 kunmap(walk->pg);
 106         else {
 107                 kunmap_atomic(walk->data);
 108                 /*
 109                  * The may sleep test only makes sense for sync users.
 110                  * Async users don't need to sleep here anyway.
 111                  */
 112                 crypto_yield(walk->flags);
 113         }
 114
 115         if (err)
 116                 return err;
 117
 118         if (nbytes) {
 119                 walk->offset = 0;
 120                 walk->pg++;
 121                 return hash_walk_next(walk);
 122         }
 123
 124         if (!walk->total)
 125                 return 0;
 126
 127         walk->sg = sg_next(walk->sg);
 128
 129         return hash_walk_new_entry(walk);
 130 }
 131 EXPORT_SYMBOL_GPL(crypto_hash_walk_done);
 132
 133 int crypto_hash_walk_first(struct ahash_request *req,
 134                            struct crypto_hash_walk *walk)
 135 {
 136         walk->total = req->nbytes;
 137
 138         if (!walk->total) {
 139                 walk->entrylen = 0;
 140                 return 0;
 141         }
 142
 143         walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
 144         walk->sg = req->src;
 145         walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK;
 146
 147         return hash_walk_new_entry(walk);
 148 }
 149 EXPORT_SYMBOL_GPL(crypto_hash_walk_first);
 150
 151 int crypto_ahash_walk_first(struct ahash_request *req,
 152                             struct crypto_hash_walk *walk)
 153 {
 154         walk->total = req->nbytes;
 155
 156         if (!walk->total) {
 157                 walk->entrylen = 0;
 158                 return 0;
 159         }
 160
 161         walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
 162         walk->sg = req->src;
 163         walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK;
 164         walk->flags |= CRYPTO_ALG_ASYNC;
 165
 166         BUILD_BUG_ON(CRYPTO_TFM_REQ_MASK & CRYPTO_ALG_ASYNC);
 167
 168         return hash_walk_new_entry(walk);
 169 }
 170 EXPORT_SYMBOL_GPL(crypto_ahash_walk_first);
 171
 172 static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,
 173                                 unsigned int keylen)
 174 {
 175         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 176         int ret;
 177         u8 *buffer, *alignbuffer;
 178         unsigned long absize;
 179
 180         absize = keylen + alignmask;
 181         buffer = kmalloc(absize, GFP_KERNEL);
 182         if (!buffer)
 183                 return -ENOMEM;
 184
 185         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 186         memcpy(alignbuffer, key, keylen);
 187         ret = tfm->setkey(tfm, alignbuffer, keylen);
 188         kzfree(buffer);
 189         return ret;
 190 }
 191
 192 int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
 193                         unsigned int keylen)
 194 {
 195         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 196         int err;
 197
 198         if ((unsigned long)key & alignmask)
 199                 err = ahash_setkey_unaligned(tfm, key, keylen);
 200         else
 201                 err = tfm->setkey(tfm, key, keylen);
 202
 203         if (err)
 204                 return err;
 205
 206         crypto_ahash_clear_flags(tfm, CRYPTO_TFM_NEED_KEY);
 207         return 0;
 208 }
 209 EXPORT_SYMBOL_GPL(crypto_ahash_setkey);
 210
 211 static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
 212                           unsigned int keylen)
 213 {
 214         return -ENOSYS;
 215 }
 216
 217 static inline unsigned int ahash_align_buffer_size(unsigned len,
 218                                                    unsigned long mask)
 219 {
 220         return len + (mask & ~(crypto_tfm_ctx_alignment() - 1));
 221 }
 222
 223 static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt)
 224 {
 225         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 226         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 227         unsigned int ds = crypto_ahash_digestsize(tfm);
 228         struct ahash_request_priv *priv;
 229
 230         priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
 231                        (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
 232                        GFP_KERNEL : GFP_ATOMIC);
 233         if (!priv)
 234                 return -ENOMEM;
 235
 236         /*
 237          * WARNING: Voodoo programming below!
 238          *
 239          * The code below is obscure and hard to understand, thus explanation
 240          * is necessary. See include/crypto/hash.h and include/linux/crypto.h
 241          * to understand the layout of structures used here!
 242          *
 243          * The code here will replace portions of the ORIGINAL request with
 244          * pointers to new code and buffers so the hashing operation can store
 245          * the result in aligned buffer. We will call the modified request
 246          * an ADJUSTED request.
 247          *
 248          * The newly mangled request will look as such:
 249          *
 250          * req {
 251          *   .result        = ADJUSTED[new aligned buffer]
 252          *   .base.complete = ADJUSTED[pointer to completion function]
 253          *   .base.data     = ADJUSTED[*req (pointer to self)]
 254          *   .priv          = ADJUSTED[new priv] {
 255          *           .result   = ORIGINAL(result)
 256          *           .complete = ORIGINAL(base.complete)
 257          *           .data     = ORIGINAL(base.data)
 258          *   }
 259          */
 260
 261         priv->result = req->result;
 262         priv->complete = req->base.complete;
 263         priv->data = req->base.data;
 264         priv->flags = req->base.flags;
 265
 266         /*
 267          * WARNING: We do not backup req->priv here! The req->priv
 268          *          is for internal use of the Crypto API and the
 269          *          user must _NOT_ _EVER_ depend on it's content!
 270          */
 271
 272         req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
 273         req->base.complete = cplt;
 274         req->base.data = req;
 275         req->priv = priv;
 276
 277         return 0;
 278 }
 279
 280 static void ahash_restore_req(struct ahash_request *req, int err)
 281 {
 282         struct ahash_request_priv *priv = req->priv;
 283
 284         if (!err)
 285                 memcpy(priv->result, req->result,
 286                        crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
 287
 288         /* Restore the original crypto request. */
 289         req->result = priv->result;
 290
 291         ahash_request_set_callback(req, priv->flags,
 292                                    priv->complete, 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_notify_einprogress(struct ahash_request *req)
 300 {
 301         struct ahash_request_priv *priv = req->priv;
 302         struct crypto_async_request oreq;
 303
 304         oreq.data = priv->data;
 305
 306         priv->complete(&oreq, -EINPROGRESS);
 307 }
 308
 309 static void ahash_op_unaligned_done(struct crypto_async_request *req, int err)
 310 {
 311         struct ahash_request *areq = req->data;
 312
 313         if (err == -EINPROGRESS) {
 314                 ahash_notify_einprogress(areq);
 315                 return;
 316         }
 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_restore_req(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         if (err == -EINPROGRESS || err == -EBUSY)
 345                 return err;
 346
 347         ahash_restore_req(req, err);
 348
 349         return err;
 350 }
 351
 352 static int crypto_ahash_op(struct ahash_request *req,
 353                            int (*op)(struct ahash_request *))
 354 {
 355         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 356         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 357
 358         if ((unsigned long)req->result & alignmask)
 359                 return ahash_op_unaligned(req, op);
 360
 361         return op(req);
 362 }
 363
 364 int crypto_ahash_final(struct ahash_request *req)
 365 {
 366         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
 367 }
 368 EXPORT_SYMBOL_GPL(crypto_ahash_final);
 369
 370 int crypto_ahash_finup(struct ahash_request *req)
 371 {
 372         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
 373 }
 374 EXPORT_SYMBOL_GPL(crypto_ahash_finup);
 375
 376 int crypto_ahash_digest(struct ahash_request *req)
 377 {
 378         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 379
 380         if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
 381                 return -ENOKEY;
 382
 383         return crypto_ahash_op(req, tfm->digest);
 384 }
 385 EXPORT_SYMBOL_GPL(crypto_ahash_digest);
 386
 387 static void ahash_def_finup_done2(struct crypto_async_request *req, int err)
 388 {
 389         struct ahash_request *areq = req->data;
 390
 391         if (err == -EINPROGRESS)
 392                 return;
 393
 394         ahash_restore_req(areq, err);
 395
 396         areq->base.complete(&areq->base, err);
 397 }
 398
 399 static int ahash_def_finup_finish1(struct ahash_request *req, int err)
 400 {
 401         if (err)
 402                 goto out;
 403
 404         req->base.complete = ahash_def_finup_done2;
 405
 406         err = crypto_ahash_reqtfm(req)->final(req);
 407         if (err == -EINPROGRESS || err == -EBUSY)
 408                 return err;
 409
 410 out:
 411         ahash_restore_req(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         if (err == -EINPROGRESS) {
 420                 ahash_notify_einprogress(areq);
 421                 return;
 422         }
 423
 424         areq->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
 425
 426         err = ahash_def_finup_finish1(areq, err);
 427         if (areq->priv)
 428                 return;
 429
 430         areq->base.complete(&areq->base, err);
 431 }
 432
 433 static int ahash_def_finup(struct ahash_request *req)
 434 {
 435         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 436         int err;
 437
 438         err = ahash_save_req(req, ahash_def_finup_done1);
 439         if (err)
 440                 return err;
 441
 442         err = tfm->update(req);
 443         if (err == -EINPROGRESS || err == -EBUSY)
 444                 return err;
 445
 446         return ahash_def_finup_finish1(req, err);
 447 }
 448
 449 static int ahash_no_export(struct ahash_request *req, void *out)
 450 {
 451         return -ENOSYS;
 452 }
 453
 454 static int ahash_no_import(struct ahash_request *req, const void *in)
 455 {
 456         return -ENOSYS;
 457 }
 458
 459 static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
 460 {
 461         struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
 462         struct ahash_alg *alg = crypto_ahash_alg(hash);
 463
 464         hash->setkey = ahash_nosetkey;
 465         hash->export = ahash_no_export;
 466         hash->import = ahash_no_import;
 467
 468         if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
 469                 return crypto_init_shash_ops_async(tfm);
 470
 471         hash->init = alg->init;
 472         hash->update = alg->update;
 473         hash->final = alg->final;
 474         hash->finup = alg->finup ?: ahash_def_finup;
 475         hash->digest = alg->digest;
 476
 477         if (alg->setkey) {
 478                 hash->setkey = alg->setkey;
 479                 if (!(alg->halg.base.cra_flags & CRYPTO_ALG_OPTIONAL_KEY))
 480                         crypto_ahash_set_flags(hash, CRYPTO_TFM_NEED_KEY);
 481         }
 482         if (alg->export)
 483                 hash->export = alg->export;
 484         if (alg->import)
 485                 hash->import = alg->import;
 486
 487         return 0;
 488 }
 489
 490 static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
 491 {
 492         if (alg->cra_type != &crypto_ahash_type)
 493                 return sizeof(struct crypto_shash *);
 494
 495         return crypto_alg_extsize(alg);
 496 }
 497
 498 #ifdef CONFIG_NET
 499 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 500 {
 501         struct crypto_report_hash rhash;
 502
 503         strncpy(rhash.type, "ahash", sizeof(rhash.type));
 504
 505         rhash.blocksize = alg->cra_blocksize;
 506         rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
 507
 508         if (nla_put(skb, CRYPTOCFGA_REPORT_HASH,
 509                     sizeof(struct crypto_report_hash), &rhash))
 510                 goto nla_put_failure;
 511         return 0;
 512
 513 nla_put_failure:
 514         return -EMSGSIZE;
 515 }
 516 #else
 517 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 518 {
 519         return -ENOSYS;
 520 }
 521 #endif
 522
 523 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 524         __maybe_unused;
 525 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 526 {
 527         seq_printf(m, "type         : ahash\n");
 528         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 529                                              "yes" : "no");
 530         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 531         seq_printf(m, "digestsize   : %u\n",
 532                    __crypto_hash_alg_common(alg)->digestsize);
 533 }
 534
 535 const struct crypto_type crypto_ahash_type = {
 536         .extsize = crypto_ahash_extsize,
 537         .init_tfm = crypto_ahash_init_tfm,
 538 #ifdef CONFIG_PROC_FS
 539         .show = crypto_ahash_show,
 540 #endif
 541         .report = crypto_ahash_report,
 542         .maskclear = ~CRYPTO_ALG_TYPE_MASK,
 543         .maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
 544         .type = CRYPTO_ALG_TYPE_AHASH,
 545         .tfmsize = offsetof(struct crypto_ahash, base),
 546 };
 547 EXPORT_SYMBOL_GPL(crypto_ahash_type);
 548
 549 struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
 550                                         u32 mask)
 551 {
 552         return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
 553 }
 554 EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
 555
 556 int crypto_has_ahash(const char *alg_name, u32 type, u32 mask)
 557 {
 558         return crypto_type_has_alg(alg_name, &crypto_ahash_type, type, mask);
 559 }
 560 EXPORT_SYMBOL_GPL(crypto_has_ahash);
 561
 562 static int ahash_prepare_alg(struct ahash_alg *alg)
 563 {
 564         struct crypto_alg *base = &alg->halg.base;
 565
 566         if (alg->halg.digestsize > PAGE_SIZE / 8 ||
 567             alg->halg.statesize > PAGE_SIZE / 8 ||
 568             alg->halg.statesize == 0)
 569                 return -EINVAL;
 570
 571         base->cra_type = &crypto_ahash_type;
 572         base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
 573         base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
 574
 575         return 0;
 576 }
 577
 578 int crypto_register_ahash(struct ahash_alg *alg)
 579 {
 580         struct crypto_alg *base = &alg->halg.base;
 581         int err;
 582
 583         err = ahash_prepare_alg(alg);
 584         if (err)
 585                 return err;
 586
 587         return crypto_register_alg(base);
 588 }
 589 EXPORT_SYMBOL_GPL(crypto_register_ahash);
 590
 591 int crypto_unregister_ahash(struct ahash_alg *alg)
 592 {
 593         return crypto_unregister_alg(&alg->halg.base);
 594 }
 595 EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
 596
 597 int crypto_register_ahashes(struct ahash_alg *algs, int count)
 598 {
 599         int i, ret;
 600
 601         for (i = 0; i < count; i++) {
 602                 ret = crypto_register_ahash(&algs[i]);
 603                 if (ret)
 604                         goto err;
 605         }
 606
 607         return 0;
 608
 609 err:
 610         for (--i; i >= 0; --i)
 611                 crypto_unregister_ahash(&algs[i]);
 612
 613         return ret;
 614 }
 615 EXPORT_SYMBOL_GPL(crypto_register_ahashes);
 616
 617 void crypto_unregister_ahashes(struct ahash_alg *algs, int count)
 618 {
 619         int i;
 620
 621         for (i = count - 1; i >= 0; --i)
 622                 crypto_unregister_ahash(&algs[i]);
 623 }
 624 EXPORT_SYMBOL_GPL(crypto_unregister_ahashes);
 625
 626 int ahash_register_instance(struct crypto_template *tmpl,
 627                             struct ahash_instance *inst)
 628 {
 629         int err;
 630
 631         err = ahash_prepare_alg(&inst->alg);
 632         if (err)
 633                 return err;
 634
 635         return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
 636 }
 637 EXPORT_SYMBOL_GPL(ahash_register_instance);
 638
 639 void ahash_free_instance(struct crypto_instance *inst)
 640 {
 641         crypto_drop_spawn(crypto_instance_ctx(inst));
 642         kfree(ahash_instance(inst));
 643 }
 644 EXPORT_SYMBOL_GPL(ahash_free_instance);
 645
 646 int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
 647                             struct hash_alg_common *alg,
 648                             struct crypto_instance *inst)
 649 {
 650         return crypto_init_spawn2(&spawn->base, &alg->base, inst,
 651                                   &crypto_ahash_type);
 652 }
 653 EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn);
 654
 655 struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
 656 {
 657         struct crypto_alg *alg;
 658
 659         alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask);
 660         return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg);
 661 }
 662 EXPORT_SYMBOL_GPL(ahash_attr_alg);
 663
 664 bool crypto_hash_alg_has_setkey(struct hash_alg_common *halg)
 665 {
 666         struct crypto_alg *alg = &halg->base;
 667
 668         if (alg->cra_type != &crypto_ahash_type)
 669                 return crypto_shash_alg_has_setkey(__crypto_shash_alg(alg));
 670
 671         return __crypto_ahash_alg(alg)->setkey != NULL;
 672 }
 673 EXPORT_SYMBOL_GPL(crypto_hash_alg_has_setkey);
 674
 675 MODULE_LICENSE("GPL");
 676 MODULE_DESCRIPTION("Asynchronous cryptographic hash type");