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
 197         if ((unsigned long)key & alignmask)
 198                 return ahash_setkey_unaligned(tfm, key, keylen);
 199
 200         return tfm->setkey(tfm, key, keylen);
 201 }
 202 EXPORT_SYMBOL_GPL(crypto_ahash_setkey);
 203
 204 static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
 205                           unsigned int keylen)
 206 {
 207         return -ENOSYS;
 208 }
 209
 210 static inline unsigned int ahash_align_buffer_size(unsigned len,
 211                                                    unsigned long mask)
 212 {
 213         return len + (mask & ~(crypto_tfm_ctx_alignment() - 1));
 214 }
 215
 216 static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt)
 217 {
 218         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 219         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 220         unsigned int ds = crypto_ahash_digestsize(tfm);
 221         struct ahash_request_priv *priv;
 222
 223         priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
 224                        (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
 225                        GFP_KERNEL : GFP_ATOMIC);
 226         if (!priv)
 227                 return -ENOMEM;
 228
 229         /*
 230          * WARNING: Voodoo programming below!
 231          *
 232          * The code below is obscure and hard to understand, thus explanation
 233          * is necessary. See include/crypto/hash.h and include/linux/crypto.h
 234          * to understand the layout of structures used here!
 235          *
 236          * The code here will replace portions of the ORIGINAL request with
 237          * pointers to new code and buffers so the hashing operation can store
 238          * the result in aligned buffer. We will call the modified request
 239          * an ADJUSTED request.
 240          *
 241          * The newly mangled request will look as such:
 242          *
 243          * req {
 244          *   .result        = ADJUSTED[new aligned buffer]
 245          *   .base.complete = ADJUSTED[pointer to completion function]
 246          *   .base.data     = ADJUSTED[*req (pointer to self)]
 247          *   .priv          = ADJUSTED[new priv] {
 248          *           .result   = ORIGINAL(result)
 249          *           .complete = ORIGINAL(base.complete)
 250          *           .data     = ORIGINAL(base.data)
 251          *   }
 252          */
 253
 254         priv->result = req->result;
 255         priv->complete = req->base.complete;
 256         priv->data = req->base.data;
 257         priv->flags = req->base.flags;
 258
 259         /*
 260          * WARNING: We do not backup req->priv here! The req->priv
 261          *          is for internal use of the Crypto API and the
 262          *          user must _NOT_ _EVER_ depend on it's content!
 263          */
 264
 265         req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
 266         req->base.complete = cplt;
 267         req->base.data = req;
 268         req->priv = priv;
 269
 270         return 0;
 271 }
 272
 273 static void ahash_restore_req(struct ahash_request *req, int err)
 274 {
 275         struct ahash_request_priv *priv = req->priv;
 276
 277         if (!err)
 278                 memcpy(priv->result, req->result,
 279                        crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
 280
 281         /* Restore the original crypto request. */
 282         req->result = priv->result;
 283
 284         ahash_request_set_callback(req, priv->flags,
 285                                    priv->complete, priv->data);
 286         req->priv = NULL;
 287
 288         /* Free the req->priv.priv from the ADJUSTED request. */
 289         kzfree(priv);
 290 }
 291
 292 static void ahash_notify_einprogress(struct ahash_request *req)
 293 {
 294         struct ahash_request_priv *priv = req->priv;
 295         struct crypto_async_request oreq;
 296
 297         oreq.data = priv->data;
 298
 299         priv->complete(&oreq, -EINPROGRESS);
 300 }
 301
 302 static void ahash_op_unaligned_done(struct crypto_async_request *req, int err)
 303 {
 304         struct ahash_request *areq = req->data;
 305
 306         if (err == -EINPROGRESS) {
 307                 ahash_notify_einprogress(areq);
 308                 return;
 309         }
 310
 311         /*
 312          * Restore the original request, see ahash_op_unaligned() for what
 313          * goes where.
 314          *
 315          * The "struct ahash_request *req" here is in fact the "req.base"
 316          * from the ADJUSTED request from ahash_op_unaligned(), thus as it
 317          * is a pointer to self, it is also the ADJUSTED "req" .
 318          */
 319
 320         /* First copy req->result into req->priv.result */
 321         ahash_restore_req(areq, err);
 322
 323         /* Complete the ORIGINAL request. */
 324         areq->base.complete(&areq->base, err);
 325 }
 326
 327 static int ahash_op_unaligned(struct ahash_request *req,
 328                               int (*op)(struct ahash_request *))
 329 {
 330         int err;
 331
 332         err = ahash_save_req(req, ahash_op_unaligned_done);
 333         if (err)
 334                 return err;
 335
 336         err = op(req);
 337         if (err == -EINPROGRESS ||
 338             (err == -EBUSY && (ahash_request_flags(req) &
 339                                CRYPTO_TFM_REQ_MAY_BACKLOG)))
 340                 return err;
 341
 342         ahash_restore_req(req, err);
 343
 344         return err;
 345 }
 346
 347 static int crypto_ahash_op(struct ahash_request *req,
 348                            int (*op)(struct ahash_request *))
 349 {
 350         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 351         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 352
 353         if ((unsigned long)req->result & alignmask)
 354                 return ahash_op_unaligned(req, op);
 355
 356         return op(req);
 357 }
 358
 359 int crypto_ahash_final(struct ahash_request *req)
 360 {
 361         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
 362 }
 363 EXPORT_SYMBOL_GPL(crypto_ahash_final);
 364
 365 int crypto_ahash_finup(struct ahash_request *req)
 366 {
 367         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
 368 }
 369 EXPORT_SYMBOL_GPL(crypto_ahash_finup);
 370
 371 int crypto_ahash_digest(struct ahash_request *req)
 372 {
 373         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->digest);
 374 }
 375 EXPORT_SYMBOL_GPL(crypto_ahash_digest);
 376
 377 static void ahash_def_finup_done2(struct crypto_async_request *req, int err)
 378 {
 379         struct ahash_request *areq = req->data;
 380
 381         if (err == -EINPROGRESS)
 382                 return;
 383
 384         ahash_restore_req(areq, err);
 385
 386         areq->base.complete(&areq->base, err);
 387 }
 388
 389 static int ahash_def_finup_finish1(struct ahash_request *req, int err)
 390 {
 391         if (err)
 392                 goto out;
 393
 394         req->base.complete = ahash_def_finup_done2;
 395
 396         err = crypto_ahash_reqtfm(req)->final(req);
 397         if (err == -EINPROGRESS ||
 398             (err == -EBUSY && (ahash_request_flags(req) &
 399                                CRYPTO_TFM_REQ_MAY_BACKLOG)))
 400                 return err;
 401
 402 out:
 403         ahash_restore_req(req, err);
 404         return err;
 405 }
 406
 407 static void ahash_def_finup_done1(struct crypto_async_request *req, int err)
 408 {
 409         struct ahash_request *areq = req->data;
 410
 411         if (err == -EINPROGRESS) {
 412                 ahash_notify_einprogress(areq);
 413                 return;
 414         }
 415
 416         areq->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
 417
 418         err = ahash_def_finup_finish1(areq, err);
 419         if (areq->priv)
 420                 return;
 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         if (err == -EINPROGRESS ||
 436             (err == -EBUSY && (ahash_request_flags(req) &
 437                                CRYPTO_TFM_REQ_MAY_BACKLOG)))
 438                 return err;
 439
 440         return ahash_def_finup_finish1(req, err);
 441 }
 442
 443 static int ahash_no_export(struct ahash_request *req, void *out)
 444 {
 445         return -ENOSYS;
 446 }
 447
 448 static int ahash_no_import(struct ahash_request *req, const void *in)
 449 {
 450         return -ENOSYS;
 451 }
 452
 453 static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
 454 {
 455         struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
 456         struct ahash_alg *alg = crypto_ahash_alg(hash);
 457
 458         hash->setkey = ahash_nosetkey;
 459         hash->has_setkey = false;
 460         hash->export = ahash_no_export;
 461         hash->import = ahash_no_import;
 462
 463         if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
 464                 return crypto_init_shash_ops_async(tfm);
 465
 466         hash->init = alg->init;
 467         hash->update = alg->update;
 468         hash->final = alg->final;
 469         hash->finup = alg->finup ?: ahash_def_finup;
 470         hash->digest = alg->digest;
 471
 472         if (alg->setkey) {
 473                 hash->setkey = alg->setkey;
 474                 hash->has_setkey = true;
 475         }
 476         if (alg->export)
 477                 hash->export = alg->export;
 478         if (alg->import)
 479                 hash->import = alg->import;
 480
 481         return 0;
 482 }
 483
 484 static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
 485 {
 486         if (alg->cra_type != &crypto_ahash_type)
 487                 return sizeof(struct crypto_shash *);
 488
 489         return crypto_alg_extsize(alg);
 490 }
 491
 492 #ifdef CONFIG_NET
 493 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 494 {
 495         struct crypto_report_hash rhash;
 496
 497         strncpy(rhash.type, "ahash", sizeof(rhash.type));
 498
 499         rhash.blocksize = alg->cra_blocksize;
 500         rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
 501
 502         if (nla_put(skb, CRYPTOCFGA_REPORT_HASH,
 503                     sizeof(struct crypto_report_hash), &rhash))
 504                 goto nla_put_failure;
 505         return 0;
 506
 507 nla_put_failure:
 508         return -EMSGSIZE;
 509 }
 510 #else
 511 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 512 {
 513         return -ENOSYS;
 514 }
 515 #endif
 516
 517 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 518         __maybe_unused;
 519 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 520 {
 521         seq_printf(m, "type         : ahash\n");
 522         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 523                                              "yes" : "no");
 524         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 525         seq_printf(m, "digestsize   : %u\n",
 526                    __crypto_hash_alg_common(alg)->digestsize);
 527 }
 528
 529 const struct crypto_type crypto_ahash_type = {
 530         .extsize = crypto_ahash_extsize,
 531         .init_tfm = crypto_ahash_init_tfm,
 532 #ifdef CONFIG_PROC_FS
 533         .show = crypto_ahash_show,
 534 #endif
 535         .report = crypto_ahash_report,
 536         .maskclear = ~CRYPTO_ALG_TYPE_MASK,
 537         .maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
 538         .type = CRYPTO_ALG_TYPE_AHASH,
 539         .tfmsize = offsetof(struct crypto_ahash, base),
 540 };
 541 EXPORT_SYMBOL_GPL(crypto_ahash_type);
 542
 543 struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
 544                                         u32 mask)
 545 {
 546         return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
 547 }
 548 EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
 549
 550 int crypto_has_ahash(const char *alg_name, u32 type, u32 mask)
 551 {
 552         return crypto_type_has_alg(alg_name, &crypto_ahash_type, type, mask);
 553 }
 554 EXPORT_SYMBOL_GPL(crypto_has_ahash);
 555
 556 static int ahash_prepare_alg(struct ahash_alg *alg)
 557 {
 558         struct crypto_alg *base = &alg->halg.base;
 559
 560         if (alg->halg.digestsize > PAGE_SIZE / 8 ||
 561             alg->halg.statesize > PAGE_SIZE / 8 ||
 562             alg->halg.statesize == 0)
 563                 return -EINVAL;
 564
 565         base->cra_type = &crypto_ahash_type;
 566         base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
 567         base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
 568
 569         return 0;
 570 }
 571
 572 int crypto_register_ahash(struct ahash_alg *alg)
 573 {
 574         struct crypto_alg *base = &alg->halg.base;
 575         int err;
 576
 577         err = ahash_prepare_alg(alg);
 578         if (err)
 579                 return err;
 580
 581         return crypto_register_alg(base);
 582 }
 583 EXPORT_SYMBOL_GPL(crypto_register_ahash);
 584
 585 int crypto_unregister_ahash(struct ahash_alg *alg)
 586 {
 587         return crypto_unregister_alg(&alg->halg.base);
 588 }
 589 EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
 590
 591 int ahash_register_instance(struct crypto_template *tmpl,
 592                             struct ahash_instance *inst)
 593 {
 594         int err;
 595
 596         err = ahash_prepare_alg(&inst->alg);
 597         if (err)
 598                 return err;
 599
 600         return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
 601 }
 602 EXPORT_SYMBOL_GPL(ahash_register_instance);
 603
 604 void ahash_free_instance(struct crypto_instance *inst)
 605 {
 606         crypto_drop_spawn(crypto_instance_ctx(inst));
 607         kfree(ahash_instance(inst));
 608 }
 609 EXPORT_SYMBOL_GPL(ahash_free_instance);
 610
 611 int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
 612                             struct hash_alg_common *alg,
 613                             struct crypto_instance *inst)
 614 {
 615         return crypto_init_spawn2(&spawn->base, &alg->base, inst,
 616                                   &crypto_ahash_type);
 617 }
 618 EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn);
 619
 620 struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
 621 {
 622         struct crypto_alg *alg;
 623
 624         alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask);
 625         return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg);
 626 }
 627 EXPORT_SYMBOL_GPL(ahash_attr_alg);
 628
 629 MODULE_LICENSE("GPL");
 630 MODULE_DESCRIPTION("Asynchronous cryptographic hash type");