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                 if (nbytes > unaligned)
  60                         nbytes = unaligned;
  61         }
  62
  63         walk->entrylen -= nbytes;
  64         return nbytes;
  65 }
  66
  67 static int hash_walk_new_entry(struct crypto_hash_walk *walk)
  68 {
  69         struct scatterlist *sg;
  70
  71         sg = walk->sg;
  72         walk->offset = sg->offset;
  73         walk->pg = sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
  74         walk->offset = offset_in_page(walk->offset);
  75         walk->entrylen = sg->length;
  76
  77         if (walk->entrylen > walk->total)
  78                 walk->entrylen = walk->total;
  79         walk->total -= walk->entrylen;
  80
  81         return hash_walk_next(walk);
  82 }
  83
  84 int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
  85 {
  86         unsigned int alignmask = walk->alignmask;
  87         unsigned int nbytes = walk->entrylen;
  88
  89         walk->data -= walk->offset;
  90
  91         if (nbytes && walk->offset & alignmask && !err) {
  92                 walk->offset = ALIGN(walk->offset, alignmask + 1);
  93                 walk->data += walk->offset;
  94
  95                 nbytes = min(nbytes,
  96                              ((unsigned int)(PAGE_SIZE)) - walk->offset);
  97                 walk->entrylen -= nbytes;
  98
  99                 return nbytes;
 100         }
 101
 102         if (walk->flags & CRYPTO_ALG_ASYNC)
 103                 kunmap(walk->pg);
 104         else {
 105                 kunmap_atomic(walk->data);
 106                 /*
 107                  * The may sleep test only makes sense for sync users.
 108                  * Async users don't need to sleep here anyway.
 109                  */
 110                 crypto_yield(walk->flags);
 111         }
 112
 113         if (err)
 114                 return err;
 115
 116         if (nbytes) {
 117                 walk->offset = 0;
 118                 walk->pg++;
 119                 return hash_walk_next(walk);
 120         }
 121
 122         if (!walk->total)
 123                 return 0;
 124
 125         walk->sg = scatterwalk_sg_next(walk->sg);
 126
 127         return hash_walk_new_entry(walk);
 128 }
 129 EXPORT_SYMBOL_GPL(crypto_hash_walk_done);
 130
 131 int crypto_hash_walk_first(struct ahash_request *req,
 132                            struct crypto_hash_walk *walk)
 133 {
 134         walk->total = req->nbytes;
 135
 136         if (!walk->total)
 137                 return 0;
 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                 return 0;
 154
 155         walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
 156         walk->sg = req->src;
 157         walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK;
 158         walk->flags |= CRYPTO_ALG_ASYNC;
 159
 160         BUILD_BUG_ON(CRYPTO_TFM_REQ_MASK & CRYPTO_ALG_ASYNC);
 161
 162         return hash_walk_new_entry(walk);
 163 }
 164 EXPORT_SYMBOL_GPL(crypto_ahash_walk_first);
 165
 166 int crypto_hash_walk_first_compat(struct hash_desc *hdesc,
 167                                   struct crypto_hash_walk *walk,
 168                                   struct scatterlist *sg, unsigned int len)
 169 {
 170         walk->total = len;
 171
 172         if (!walk->total)
 173                 return 0;
 174
 175         walk->alignmask = crypto_hash_alignmask(hdesc->tfm);
 176         walk->sg = sg;
 177         walk->flags = hdesc->flags & CRYPTO_TFM_REQ_MASK;
 178
 179         return hash_walk_new_entry(walk);
 180 }
 181
 182 static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,
 183                                 unsigned int keylen)
 184 {
 185         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 186         int ret;
 187         u8 *buffer, *alignbuffer;
 188         unsigned long absize;
 189
 190         absize = keylen + alignmask;
 191         buffer = kmalloc(absize, GFP_KERNEL);
 192         if (!buffer)
 193                 return -ENOMEM;
 194
 195         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 196         memcpy(alignbuffer, key, keylen);
 197         ret = tfm->setkey(tfm, alignbuffer, keylen);
 198         kzfree(buffer);
 199         return ret;
 200 }
 201
 202 int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
 203                         unsigned int keylen)
 204 {
 205         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 206
 207         if ((unsigned long)key & alignmask)
 208                 return ahash_setkey_unaligned(tfm, key, keylen);
 209
 210         return tfm->setkey(tfm, key, keylen);
 211 }
 212 EXPORT_SYMBOL_GPL(crypto_ahash_setkey);
 213
 214 static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
 215                           unsigned int keylen)
 216 {
 217         return -ENOSYS;
 218 }
 219
 220 static inline unsigned int ahash_align_buffer_size(unsigned len,
 221                                                    unsigned long mask)
 222 {
 223         return len + (mask & ~(crypto_tfm_ctx_alignment() - 1));
 224 }
 225
 226 static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt)
 227 {
 228         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 229         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 230         unsigned int ds = crypto_ahash_digestsize(tfm);
 231         struct ahash_request_priv *priv;
 232
 233         priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
 234                        (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
 235                        GFP_KERNEL : GFP_ATOMIC);
 236         if (!priv)
 237                 return -ENOMEM;
 238
 239         /*
 240          * WARNING: Voodoo programming below!
 241          *
 242          * The code below is obscure and hard to understand, thus explanation
 243          * is necessary. See include/crypto/hash.h and include/linux/crypto.h
 244          * to understand the layout of structures used here!
 245          *
 246          * The code here will replace portions of the ORIGINAL request with
 247          * pointers to new code and buffers so the hashing operation can store
 248          * the result in aligned buffer. We will call the modified request
 249          * an ADJUSTED request.
 250          *
 251          * The newly mangled request will look as such:
 252          *
 253          * req {
 254          *   .result        = ADJUSTED[new aligned buffer]
 255          *   .base.complete = ADJUSTED[pointer to completion function]
 256          *   .base.data     = ADJUSTED[*req (pointer to self)]
 257          *   .priv          = ADJUSTED[new priv] {
 258          *           .result   = ORIGINAL(result)
 259          *           .complete = ORIGINAL(base.complete)
 260          *           .data     = ORIGINAL(base.data)
 261          *   }
 262          */
 263
 264         priv->result = req->result;
 265         priv->complete = req->base.complete;
 266         priv->data = req->base.data;
 267         priv->flags = req->base.flags;
 268
 269         /*
 270          * WARNING: We do not backup req->priv here! The req->priv
 271          *          is for internal use of the Crypto API and the
 272          *          user must _NOT_ _EVER_ depend on it's content!
 273          */
 274
 275         req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
 276         req->base.complete = cplt;
 277         req->base.data = req;
 278         req->priv = priv;
 279
 280         return 0;
 281 }
 282
 283 static void ahash_restore_req(struct ahash_request *req, int err)
 284 {
 285         struct ahash_request_priv *priv = req->priv;
 286
 287         if (!err)
 288                 memcpy(priv->result, req->result,
 289                        crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
 290
 291         /* Restore the original crypto request. */
 292         req->result = priv->result;
 293
 294         ahash_request_set_callback(req, priv->flags,
 295                                    priv->complete, priv->data);
 296         req->priv = NULL;
 297
 298         /* Free the req->priv.priv from the ADJUSTED request. */
 299         kzfree(priv);
 300 }
 301
 302 static void ahash_notify_einprogress(struct ahash_request *req)
 303 {
 304         struct ahash_request_priv *priv = req->priv;
 305         struct crypto_async_request oreq;
 306
 307         oreq.data = priv->data;
 308
 309         priv->complete(&oreq, -EINPROGRESS);
 310 }
 311
 312 static void ahash_op_unaligned_done(struct crypto_async_request *req, int err)
 313 {
 314         struct ahash_request *areq = req->data;
 315
 316         if (err == -EINPROGRESS) {
 317                 ahash_notify_einprogress(areq);
 318                 return;
 319         }
 320
 321         /*
 322          * Restore the original request, see ahash_op_unaligned() for what
 323          * goes where.
 324          *
 325          * The "struct ahash_request *req" here is in fact the "req.base"
 326          * from the ADJUSTED request from ahash_op_unaligned(), thus as it
 327          * is a pointer to self, it is also the ADJUSTED "req" .
 328          */
 329
 330         /* First copy req->result into req->priv.result */
 331         ahash_restore_req(areq, err);
 332
 333         /* Complete the ORIGINAL request. */
 334         areq->base.complete(&areq->base, err);
 335 }
 336
 337 static int ahash_op_unaligned(struct ahash_request *req,
 338                               int (*op)(struct ahash_request *))
 339 {
 340         int err;
 341
 342         err = ahash_save_req(req, ahash_op_unaligned_done);
 343         if (err)
 344                 return err;
 345
 346         err = op(req);
 347         if (err == -EINPROGRESS ||
 348             (err == -EBUSY && (ahash_request_flags(req) &
 349                                CRYPTO_TFM_REQ_MAY_BACKLOG)))
 350                 return err;
 351
 352         ahash_restore_req(req, err);
 353
 354         return err;
 355 }
 356
 357 static int crypto_ahash_op(struct ahash_request *req,
 358                            int (*op)(struct ahash_request *))
 359 {
 360         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 361         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 362
 363         if ((unsigned long)req->result & alignmask)
 364                 return ahash_op_unaligned(req, op);
 365
 366         return op(req);
 367 }
 368
 369 int crypto_ahash_final(struct ahash_request *req)
 370 {
 371         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
 372 }
 373 EXPORT_SYMBOL_GPL(crypto_ahash_final);
 374
 375 int crypto_ahash_finup(struct ahash_request *req)
 376 {
 377         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
 378 }
 379 EXPORT_SYMBOL_GPL(crypto_ahash_finup);
 380
 381 int crypto_ahash_digest(struct ahash_request *req)
 382 {
 383         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->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 ||
 408             (err == -EBUSY && (ahash_request_flags(req) &
 409                                CRYPTO_TFM_REQ_MAY_BACKLOG)))
 410                 return err;
 411
 412 out:
 413         ahash_restore_req(req, err);
 414         return err;
 415 }
 416
 417 static void ahash_def_finup_done1(struct crypto_async_request *req, int err)
 418 {
 419         struct ahash_request *areq = req->data;
 420
 421         if (err == -EINPROGRESS) {
 422                 ahash_notify_einprogress(areq);
 423                 return;
 424         }
 425
 426         areq->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
 427
 428         err = ahash_def_finup_finish1(areq, err);
 429         if (areq->priv)
 430                 return;
 431
 432         areq->base.complete(&areq->base, err);
 433 }
 434
 435 static int ahash_def_finup(struct ahash_request *req)
 436 {
 437         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 438         int err;
 439
 440         err = ahash_save_req(req, ahash_def_finup_done1);
 441         if (err)
 442                 return err;
 443
 444         err = tfm->update(req);
 445         if (err == -EINPROGRESS ||
 446             (err == -EBUSY && (ahash_request_flags(req) &
 447                                CRYPTO_TFM_REQ_MAY_BACKLOG)))
 448                 return err;
 449
 450         return ahash_def_finup_finish1(req, err);
 451 }
 452
 453 static int ahash_no_export(struct ahash_request *req, void *out)
 454 {
 455         return -ENOSYS;
 456 }
 457
 458 static int ahash_no_import(struct ahash_request *req, const void *in)
 459 {
 460         return -ENOSYS;
 461 }
 462
 463 static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
 464 {
 465         struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
 466         struct ahash_alg *alg = crypto_ahash_alg(hash);
 467
 468         hash->setkey = ahash_nosetkey;
 469         hash->has_setkey = false;
 470         hash->export = ahash_no_export;
 471         hash->import = ahash_no_import;
 472
 473         if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
 474                 return crypto_init_shash_ops_async(tfm);
 475
 476         hash->init = alg->init;
 477         hash->update = alg->update;
 478         hash->final = alg->final;
 479         hash->finup = alg->finup ?: ahash_def_finup;
 480         hash->digest = alg->digest;
 481
 482         if (alg->setkey) {
 483                 hash->setkey = alg->setkey;
 484                 hash->has_setkey = true;
 485         }
 486         if (alg->export)
 487                 hash->export = alg->export;
 488         if (alg->import)
 489                 hash->import = alg->import;
 490
 491         return 0;
 492 }
 493
 494 static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
 495 {
 496         if (alg->cra_type == &crypto_ahash_type)
 497                 return alg->cra_ctxsize;
 498
 499         return sizeof(struct crypto_shash *);
 500 }
 501
 502 #ifdef CONFIG_NET
 503 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 504 {
 505         struct crypto_report_hash rhash;
 506
 507         strncpy(rhash.type, "ahash", sizeof(rhash.type));
 508
 509         rhash.blocksize = alg->cra_blocksize;
 510         rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
 511
 512         if (nla_put(skb, CRYPTOCFGA_REPORT_HASH,
 513                     sizeof(struct crypto_report_hash), &rhash))
 514                 goto nla_put_failure;
 515         return 0;
 516
 517 nla_put_failure:
 518         return -EMSGSIZE;
 519 }
 520 #else
 521 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 522 {
 523         return -ENOSYS;
 524 }
 525 #endif
 526
 527 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 528         __attribute__ ((unused));
 529 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 530 {
 531         seq_printf(m, "type         : ahash\n");
 532         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 533                                              "yes" : "no");
 534         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 535         seq_printf(m, "digestsize   : %u\n",
 536                    __crypto_hash_alg_common(alg)->digestsize);
 537 }
 538
 539 const struct crypto_type crypto_ahash_type = {
 540         .extsize = crypto_ahash_extsize,
 541         .init_tfm = crypto_ahash_init_tfm,
 542 #ifdef CONFIG_PROC_FS
 543         .show = crypto_ahash_show,
 544 #endif
 545         .report = crypto_ahash_report,
 546         .maskclear = ~CRYPTO_ALG_TYPE_MASK,
 547         .maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
 548         .type = CRYPTO_ALG_TYPE_AHASH,
 549         .tfmsize = offsetof(struct crypto_ahash, base),
 550 };
 551 EXPORT_SYMBOL_GPL(crypto_ahash_type);
 552
 553 struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
 554                                         u32 mask)
 555 {
 556         return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
 557 }
 558 EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
 559
 560 static int ahash_prepare_alg(struct ahash_alg *alg)
 561 {
 562         struct crypto_alg *base = &alg->halg.base;
 563
 564         if (alg->halg.digestsize > PAGE_SIZE / 8 ||
 565             alg->halg.statesize > PAGE_SIZE / 8 ||
 566             alg->halg.statesize == 0)
 567                 return -EINVAL;
 568
 569         base->cra_type = &crypto_ahash_type;
 570         base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
 571         base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
 572
 573         return 0;
 574 }
 575
 576 int crypto_register_ahash(struct ahash_alg *alg)
 577 {
 578         struct crypto_alg *base = &alg->halg.base;
 579         int err;
 580
 581         err = ahash_prepare_alg(alg);
 582         if (err)
 583                 return err;
 584
 585         return crypto_register_alg(base);
 586 }
 587 EXPORT_SYMBOL_GPL(crypto_register_ahash);
 588
 589 int crypto_unregister_ahash(struct ahash_alg *alg)
 590 {
 591         return crypto_unregister_alg(&alg->halg.base);
 592 }
 593 EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
 594
 595 int ahash_register_instance(struct crypto_template *tmpl,
 596                             struct ahash_instance *inst)
 597 {
 598         int err;
 599
 600         err = ahash_prepare_alg(&inst->alg);
 601         if (err)
 602                 return err;
 603
 604         return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
 605 }
 606 EXPORT_SYMBOL_GPL(ahash_register_instance);
 607
 608 void ahash_free_instance(struct crypto_instance *inst)
 609 {
 610         crypto_drop_spawn(crypto_instance_ctx(inst));
 611         kfree(ahash_instance(inst));
 612 }
 613 EXPORT_SYMBOL_GPL(ahash_free_instance);
 614
 615 int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
 616                             struct hash_alg_common *alg,
 617                             struct crypto_instance *inst)
 618 {
 619         return crypto_init_spawn2(&spawn->base, &alg->base, inst,
 620                                   &crypto_ahash_type);
 621 }
 622 EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn);
 623
 624 struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
 625 {
 626         struct crypto_alg *alg;
 627
 628         alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask);
 629         return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg);
 630 }
 631 EXPORT_SYMBOL_GPL(ahash_attr_alg);
 632
 633 MODULE_LICENSE("GPL");
 634 MODULE_DESCRIPTION("Asynchronous cryptographic hash type");