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                 nbytes = min(nbytes,
  95                              ((unsigned int)(PAGE_SIZE)) - walk->offset);
  96                 walk->entrylen -= nbytes;
  97
  98                 if (nbytes) {
  99                         walk->data += walk->offset;
 100                         return nbytes;
 101                 }
 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 ||
 345             (err == -EBUSY && (ahash_request_flags(req) &
 346                                CRYPTO_TFM_REQ_MAY_BACKLOG)))
 347                 return err;
 348
 349         ahash_restore_req(req, err);
 350
 351         return err;
 352 }
 353
 354 static int crypto_ahash_op(struct ahash_request *req,
 355                            int (*op)(struct ahash_request *))
 356 {
 357         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 358         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 359
 360         if ((unsigned long)req->result & alignmask)
 361                 return ahash_op_unaligned(req, op);
 362
 363         return op(req);
 364 }
 365
 366 int crypto_ahash_final(struct ahash_request *req)
 367 {
 368         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
 369 }
 370 EXPORT_SYMBOL_GPL(crypto_ahash_final);
 371
 372 int crypto_ahash_finup(struct ahash_request *req)
 373 {
 374         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
 375 }
 376 EXPORT_SYMBOL_GPL(crypto_ahash_finup);
 377
 378 int crypto_ahash_digest(struct ahash_request *req)
 379 {
 380         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 381
 382         if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
 383                 return -ENOKEY;
 384
 385         return crypto_ahash_op(req, tfm->digest);
 386 }
 387 EXPORT_SYMBOL_GPL(crypto_ahash_digest);
 388
 389 static void ahash_def_finup_done2(struct crypto_async_request *req, int err)
 390 {
 391         struct ahash_request *areq = req->data;
 392
 393         if (err == -EINPROGRESS)
 394                 return;
 395
 396         ahash_restore_req(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
 408         err = crypto_ahash_reqtfm(req)->final(req);
 409         if (err == -EINPROGRESS ||
 410             (err == -EBUSY && (ahash_request_flags(req) &
 411                                CRYPTO_TFM_REQ_MAY_BACKLOG)))
 412                 return err;
 413
 414 out:
 415         ahash_restore_req(req, err);
 416         return err;
 417 }
 418
 419 static void ahash_def_finup_done1(struct crypto_async_request *req, int err)
 420 {
 421         struct ahash_request *areq = req->data;
 422
 423         if (err == -EINPROGRESS) {
 424                 ahash_notify_einprogress(areq);
 425                 return;
 426         }
 427
 428         areq->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
 429
 430         err = ahash_def_finup_finish1(areq, err);
 431         if (areq->priv)
 432                 return;
 433
 434         areq->base.complete(&areq->base, err);
 435 }
 436
 437 static int ahash_def_finup(struct ahash_request *req)
 438 {
 439         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 440         int err;
 441
 442         err = ahash_save_req(req, ahash_def_finup_done1);
 443         if (err)
 444                 return err;
 445
 446         err = tfm->update(req);
 447         if (err == -EINPROGRESS ||
 448             (err == -EBUSY && (ahash_request_flags(req) &
 449                                CRYPTO_TFM_REQ_MAY_BACKLOG)))
 450                 return err;
 451
 452         return ahash_def_finup_finish1(req, err);
 453 }
 454
 455 static int ahash_no_export(struct ahash_request *req, void *out)
 456 {
 457         return -ENOSYS;
 458 }
 459
 460 static int ahash_no_import(struct ahash_request *req, const void *in)
 461 {
 462         return -ENOSYS;
 463 }
 464
 465 static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
 466 {
 467         struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
 468         struct ahash_alg *alg = crypto_ahash_alg(hash);
 469
 470         hash->setkey = ahash_nosetkey;
 471         hash->export = ahash_no_export;
 472         hash->import = ahash_no_import;
 473
 474         if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
 475                 return crypto_init_shash_ops_async(tfm);
 476
 477         hash->init = alg->init;
 478         hash->update = alg->update;
 479         hash->final = alg->final;
 480         hash->finup = alg->finup ?: ahash_def_finup;
 481         hash->digest = alg->digest;
 482
 483         if (alg->setkey) {
 484                 hash->setkey = alg->setkey;
 485                 if (!(alg->halg.base.cra_flags & CRYPTO_ALG_OPTIONAL_KEY))
 486                         crypto_ahash_set_flags(hash, CRYPTO_TFM_NEED_KEY);
 487         }
 488         if (alg->export)
 489                 hash->export = alg->export;
 490         if (alg->import)
 491                 hash->import = alg->import;
 492
 493         return 0;
 494 }
 495
 496 static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
 497 {
 498         if (alg->cra_type != &crypto_ahash_type)
 499                 return sizeof(struct crypto_shash *);
 500
 501         return crypto_alg_extsize(alg);
 502 }
 503
 504 #ifdef CONFIG_NET
 505 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 506 {
 507         struct crypto_report_hash rhash;
 508
 509         strncpy(rhash.type, "ahash", sizeof(rhash.type));
 510
 511         rhash.blocksize = alg->cra_blocksize;
 512         rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
 513
 514         if (nla_put(skb, CRYPTOCFGA_REPORT_HASH,
 515                     sizeof(struct crypto_report_hash), &rhash))
 516                 goto nla_put_failure;
 517         return 0;
 518
 519 nla_put_failure:
 520         return -EMSGSIZE;
 521 }
 522 #else
 523 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 524 {
 525         return -ENOSYS;
 526 }
 527 #endif
 528
 529 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 530         __attribute__ ((unused));
 531 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 532 {
 533         seq_printf(m, "type         : ahash\n");
 534         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 535                                              "yes" : "no");
 536         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 537         seq_printf(m, "digestsize   : %u\n",
 538                    __crypto_hash_alg_common(alg)->digestsize);
 539 }
 540
 541 const struct crypto_type crypto_ahash_type = {
 542         .extsize = crypto_ahash_extsize,
 543         .init_tfm = crypto_ahash_init_tfm,
 544 #ifdef CONFIG_PROC_FS
 545         .show = crypto_ahash_show,
 546 #endif
 547         .report = crypto_ahash_report,
 548         .maskclear = ~CRYPTO_ALG_TYPE_MASK,
 549         .maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
 550         .type = CRYPTO_ALG_TYPE_AHASH,
 551         .tfmsize = offsetof(struct crypto_ahash, base),
 552 };
 553 EXPORT_SYMBOL_GPL(crypto_ahash_type);
 554
 555 struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
 556                                         u32 mask)
 557 {
 558         return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
 559 }
 560 EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
 561
 562 int crypto_has_ahash(const char *alg_name, u32 type, u32 mask)
 563 {
 564         return crypto_type_has_alg(alg_name, &crypto_ahash_type, type, mask);
 565 }
 566 EXPORT_SYMBOL_GPL(crypto_has_ahash);
 567
 568 static int ahash_prepare_alg(struct ahash_alg *alg)
 569 {
 570         struct crypto_alg *base = &alg->halg.base;
 571
 572         if (alg->halg.digestsize > PAGE_SIZE / 8 ||
 573             alg->halg.statesize > PAGE_SIZE / 8 ||
 574             alg->halg.statesize == 0)
 575                 return -EINVAL;
 576
 577         base->cra_type = &crypto_ahash_type;
 578         base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
 579         base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
 580
 581         return 0;
 582 }
 583
 584 int crypto_register_ahash(struct ahash_alg *alg)
 585 {
 586         struct crypto_alg *base = &alg->halg.base;
 587         int err;
 588
 589         err = ahash_prepare_alg(alg);
 590         if (err)
 591                 return err;
 592
 593         return crypto_register_alg(base);
 594 }
 595 EXPORT_SYMBOL_GPL(crypto_register_ahash);
 596
 597 int crypto_unregister_ahash(struct ahash_alg *alg)
 598 {
 599         return crypto_unregister_alg(&alg->halg.base);
 600 }
 601 EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
 602
 603 int ahash_register_instance(struct crypto_template *tmpl,
 604                             struct ahash_instance *inst)
 605 {
 606         int err;
 607
 608         err = ahash_prepare_alg(&inst->alg);
 609         if (err)
 610                 return err;
 611
 612         return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
 613 }
 614 EXPORT_SYMBOL_GPL(ahash_register_instance);
 615
 616 void ahash_free_instance(struct crypto_instance *inst)
 617 {
 618         crypto_drop_spawn(crypto_instance_ctx(inst));
 619         kfree(ahash_instance(inst));
 620 }
 621 EXPORT_SYMBOL_GPL(ahash_free_instance);
 622
 623 int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
 624                             struct hash_alg_common *alg,
 625                             struct crypto_instance *inst)
 626 {
 627         return crypto_init_spawn2(&spawn->base, &alg->base, inst,
 628                                   &crypto_ahash_type);
 629 }
 630 EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn);
 631
 632 struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
 633 {
 634         struct crypto_alg *alg;
 635
 636         alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask);
 637         return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg);
 638 }
 639 EXPORT_SYMBOL_GPL(ahash_attr_alg);
 640
 641 bool crypto_hash_alg_has_setkey(struct hash_alg_common *halg)
 642 {
 643         struct crypto_alg *alg = &halg->base;
 644
 645         if (alg->cra_type != &crypto_ahash_type)
 646                 return crypto_shash_alg_has_setkey(__crypto_shash_alg(alg));
 647
 648         return __crypto_ahash_alg(alg)->setkey != NULL;
 649 }
 650 EXPORT_SYMBOL_GPL(crypto_hash_alg_has_setkey);
 651
 652 MODULE_LICENSE("GPL");
 653 MODULE_DESCRIPTION("Asynchronous cryptographic hash type");