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         void *ubuf[] CRYPTO_MINALIGN_ATTR;
  35 };
  36
  37 static inline struct ahash_alg *crypto_ahash_alg(struct crypto_ahash *hash)
  38 {
  39         return container_of(crypto_hash_alg_common(hash), struct ahash_alg,
  40                             halg);
  41 }
  42
  43 static int hash_walk_next(struct crypto_hash_walk *walk)
  44 {
  45         unsigned int alignmask = walk->alignmask;
  46         unsigned int offset = walk->offset;
  47         unsigned int nbytes = min(walk->entrylen,
  48                                   ((unsigned int)(PAGE_SIZE)) - offset);
  49
  50         if (walk->flags & CRYPTO_ALG_ASYNC)
  51                 walk->data = kmap(walk->pg);
  52         else
  53                 walk->data = kmap_atomic(walk->pg);
  54         walk->data += offset;
  55
  56         if (offset & alignmask) {
  57                 unsigned int unaligned = alignmask + 1 - (offset & alignmask);
  58
  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 = 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                 walk->entrylen = 0;
 138                 return 0;
 139         }
 140
 141         walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
 142         walk->sg = req->src;
 143         walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK;
 144
 145         return hash_walk_new_entry(walk);
 146 }
 147 EXPORT_SYMBOL_GPL(crypto_hash_walk_first);
 148
 149 int crypto_ahash_walk_first(struct ahash_request *req,
 150                             struct crypto_hash_walk *walk)
 151 {
 152         walk->total = req->nbytes;
 153
 154         if (!walk->total) {
 155                 walk->entrylen = 0;
 156                 return 0;
 157         }
 158
 159         walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
 160         walk->sg = req->src;
 161         walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK;
 162         walk->flags |= CRYPTO_ALG_ASYNC;
 163
 164         BUILD_BUG_ON(CRYPTO_TFM_REQ_MASK & CRYPTO_ALG_ASYNC);
 165
 166         return hash_walk_new_entry(walk);
 167 }
 168 EXPORT_SYMBOL_GPL(crypto_ahash_walk_first);
 169
 170 int crypto_hash_walk_first_compat(struct hash_desc *hdesc,
 171                                   struct crypto_hash_walk *walk,
 172                                   struct scatterlist *sg, unsigned int len)
 173 {
 174         walk->total = len;
 175
 176         if (!walk->total) {
 177                 walk->entrylen = 0;
 178                 return 0;
 179         }
 180
 181         walk->alignmask = crypto_hash_alignmask(hdesc->tfm);
 182         walk->sg = sg;
 183         walk->flags = hdesc->flags & CRYPTO_TFM_REQ_MASK;
 184
 185         return hash_walk_new_entry(walk);
 186 }
 187
 188 static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,
 189                                 unsigned int keylen)
 190 {
 191         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 192         int ret;
 193         u8 *buffer, *alignbuffer;
 194         unsigned long absize;
 195
 196         absize = keylen + alignmask;
 197         buffer = kmalloc(absize, GFP_KERNEL);
 198         if (!buffer)
 199                 return -ENOMEM;
 200
 201         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 202         memcpy(alignbuffer, key, keylen);
 203         ret = tfm->setkey(tfm, alignbuffer, keylen);
 204         kzfree(buffer);
 205         return ret;
 206 }
 207
 208 int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
 209                         unsigned int keylen)
 210 {
 211         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 212
 213         if ((unsigned long)key & alignmask)
 214                 return ahash_setkey_unaligned(tfm, key, keylen);
 215
 216         return tfm->setkey(tfm, key, keylen);
 217 }
 218 EXPORT_SYMBOL_GPL(crypto_ahash_setkey);
 219
 220 static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
 221                           unsigned int keylen)
 222 {
 223         return -ENOSYS;
 224 }
 225
 226 static inline unsigned int ahash_align_buffer_size(unsigned len,
 227                                                    unsigned long mask)
 228 {
 229         return len + (mask & ~(crypto_tfm_ctx_alignment() - 1));
 230 }
 231
 232 static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt)
 233 {
 234         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 235         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 236         unsigned int ds = crypto_ahash_digestsize(tfm);
 237         struct ahash_request_priv *priv;
 238
 239         priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
 240                        (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
 241                        GFP_KERNEL : GFP_ATOMIC);
 242         if (!priv)
 243                 return -ENOMEM;
 244
 245         /*
 246          * WARNING: Voodoo programming below!
 247          *
 248          * The code below is obscure and hard to understand, thus explanation
 249          * is necessary. See include/crypto/hash.h and include/linux/crypto.h
 250          * to understand the layout of structures used here!
 251          *
 252          * The code here will replace portions of the ORIGINAL request with
 253          * pointers to new code and buffers so the hashing operation can store
 254          * the result in aligned buffer. We will call the modified request
 255          * an ADJUSTED request.
 256          *
 257          * The newly mangled request will look as such:
 258          *
 259          * req {
 260          *   .result        = ADJUSTED[new aligned buffer]
 261          *   .base.complete = ADJUSTED[pointer to completion function]
 262          *   .base.data     = ADJUSTED[*req (pointer to self)]
 263          *   .priv          = ADJUSTED[new priv] {
 264          *           .result   = ORIGINAL(result)
 265          *           .complete = ORIGINAL(base.complete)
 266          *           .data     = ORIGINAL(base.data)
 267          *   }
 268          */
 269
 270         priv->result = req->result;
 271         priv->complete = req->base.complete;
 272         priv->data = req->base.data;
 273         /*
 274          * WARNING: We do not backup req->priv here! The req->priv
 275          *          is for internal use of the Crypto API and the
 276          *          user must _NOT_ _EVER_ depend on it's content!
 277          */
 278
 279         req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
 280         req->base.complete = cplt;
 281         req->base.data = req;
 282         req->priv = priv;
 283
 284         return 0;
 285 }
 286
 287 static void ahash_restore_req(struct ahash_request *req)
 288 {
 289         struct ahash_request_priv *priv = req->priv;
 290
 291         /* Restore the original crypto request. */
 292         req->result = priv->result;
 293         req->base.complete = priv->complete;
 294         req->base.data = priv->data;
 295         req->priv = NULL;
 296
 297         /* Free the req->priv.priv from the ADJUSTED request. */
 298         kzfree(priv);
 299 }
 300
 301 static void ahash_op_unaligned_finish(struct ahash_request *req, int err)
 302 {
 303         struct ahash_request_priv *priv = req->priv;
 304
 305         if (err == -EINPROGRESS)
 306                 return;
 307
 308         if (!err)
 309                 memcpy(priv->result, req->result,
 310                        crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
 311
 312         ahash_restore_req(req);
 313 }
 314
 315 static void ahash_op_unaligned_done(struct crypto_async_request *req, int err)
 316 {
 317         struct ahash_request *areq = req->data;
 318
 319         /*
 320          * Restore the original request, see ahash_op_unaligned() for what
 321          * goes where.
 322          *
 323          * The "struct ahash_request *req" here is in fact the "req.base"
 324          * from the ADJUSTED request from ahash_op_unaligned(), thus as it
 325          * is a pointer to self, it is also the ADJUSTED "req" .
 326          */
 327
 328         /* First copy req->result into req->priv.result */
 329         ahash_op_unaligned_finish(areq, err);
 330
 331         /* Complete the ORIGINAL request. */
 332         areq->base.complete(&areq->base, err);
 333 }
 334
 335 static int ahash_op_unaligned(struct ahash_request *req,
 336                               int (*op)(struct ahash_request *))
 337 {
 338         int err;
 339
 340         err = ahash_save_req(req, ahash_op_unaligned_done);
 341         if (err)
 342                 return err;
 343
 344         err = op(req);
 345         ahash_op_unaligned_finish(req, err);
 346
 347         return err;
 348 }
 349
 350 static int crypto_ahash_op(struct ahash_request *req,
 351                            int (*op)(struct ahash_request *))
 352 {
 353         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 354         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 355
 356         if ((unsigned long)req->result & alignmask)
 357                 return ahash_op_unaligned(req, op);
 358
 359         return op(req);
 360 }
 361
 362 int crypto_ahash_final(struct ahash_request *req)
 363 {
 364         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
 365 }
 366 EXPORT_SYMBOL_GPL(crypto_ahash_final);
 367
 368 int crypto_ahash_finup(struct ahash_request *req)
 369 {
 370         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
 371 }
 372 EXPORT_SYMBOL_GPL(crypto_ahash_finup);
 373
 374 int crypto_ahash_digest(struct ahash_request *req)
 375 {
 376         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->digest);
 377 }
 378 EXPORT_SYMBOL_GPL(crypto_ahash_digest);
 379
 380 static void ahash_def_finup_finish2(struct ahash_request *req, int err)
 381 {
 382         struct ahash_request_priv *priv = req->priv;
 383
 384         if (err == -EINPROGRESS)
 385                 return;
 386
 387         if (!err)
 388                 memcpy(priv->result, req->result,
 389                        crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
 390
 391         ahash_restore_req(req);
 392 }
 393
 394 static void ahash_def_finup_done2(struct crypto_async_request *req, int err)
 395 {
 396         struct ahash_request *areq = req->data;
 397
 398         ahash_def_finup_finish2(areq, err);
 399
 400         areq->base.complete(&areq->base, err);
 401 }
 402
 403 static int ahash_def_finup_finish1(struct ahash_request *req, int err)
 404 {
 405         if (err)
 406                 goto out;
 407
 408         req->base.complete = ahash_def_finup_done2;
 409         req->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
 410         err = crypto_ahash_reqtfm(req)->final(req);
 411
 412 out:
 413         ahash_def_finup_finish2(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         err = ahash_def_finup_finish1(areq, err);
 422
 423         areq->base.complete(&areq->base, err);
 424 }
 425
 426 static int ahash_def_finup(struct ahash_request *req)
 427 {
 428         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 429         int err;
 430
 431         err = ahash_save_req(req, ahash_def_finup_done1);
 432         if (err)
 433                 return err;
 434
 435         err = tfm->update(req);
 436         return ahash_def_finup_finish1(req, err);
 437 }
 438
 439 static int ahash_no_export(struct ahash_request *req, void *out)
 440 {
 441         return -ENOSYS;
 442 }
 443
 444 static int ahash_no_import(struct ahash_request *req, const void *in)
 445 {
 446         return -ENOSYS;
 447 }
 448
 449 static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
 450 {
 451         struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
 452         struct ahash_alg *alg = crypto_ahash_alg(hash);
 453
 454         hash->setkey = ahash_nosetkey;
 455         hash->has_setkey = false;
 456         hash->export = ahash_no_export;
 457         hash->import = ahash_no_import;
 458
 459         if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
 460                 return crypto_init_shash_ops_async(tfm);
 461
 462         hash->init = alg->init;
 463         hash->update = alg->update;
 464         hash->final = alg->final;
 465         hash->finup = alg->finup ?: ahash_def_finup;
 466         hash->digest = alg->digest;
 467
 468         if (alg->setkey) {
 469                 hash->setkey = alg->setkey;
 470                 hash->has_setkey = true;
 471         }
 472         if (alg->export)
 473                 hash->export = alg->export;
 474         if (alg->import)
 475                 hash->import = alg->import;
 476
 477         return 0;
 478 }
 479
 480 static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
 481 {
 482         if (alg->cra_type == &crypto_ahash_type)
 483                 return alg->cra_ctxsize;
 484
 485         return sizeof(struct crypto_shash *);
 486 }
 487
 488 #ifdef CONFIG_NET
 489 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 490 {
 491         struct crypto_report_hash rhash;
 492
 493         strncpy(rhash.type, "ahash", sizeof(rhash.type));
 494
 495         rhash.blocksize = alg->cra_blocksize;
 496         rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
 497
 498         if (nla_put(skb, CRYPTOCFGA_REPORT_HASH,
 499                     sizeof(struct crypto_report_hash), &rhash))
 500                 goto nla_put_failure;
 501         return 0;
 502
 503 nla_put_failure:
 504         return -EMSGSIZE;
 505 }
 506 #else
 507 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 508 {
 509         return -ENOSYS;
 510 }
 511 #endif
 512
 513 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 514         __attribute__ ((unused));
 515 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 516 {
 517         seq_printf(m, "type         : ahash\n");
 518         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 519                                              "yes" : "no");
 520         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 521         seq_printf(m, "digestsize   : %u\n",
 522                    __crypto_hash_alg_common(alg)->digestsize);
 523 }
 524
 525 const struct crypto_type crypto_ahash_type = {
 526         .extsize = crypto_ahash_extsize,
 527         .init_tfm = crypto_ahash_init_tfm,
 528 #ifdef CONFIG_PROC_FS
 529         .show = crypto_ahash_show,
 530 #endif
 531         .report = crypto_ahash_report,
 532         .maskclear = ~CRYPTO_ALG_TYPE_MASK,
 533         .maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
 534         .type = CRYPTO_ALG_TYPE_AHASH,
 535         .tfmsize = offsetof(struct crypto_ahash, base),
 536 };
 537 EXPORT_SYMBOL_GPL(crypto_ahash_type);
 538
 539 struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
 540                                         u32 mask)
 541 {
 542         return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
 543 }
 544 EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
 545
 546 static int ahash_prepare_alg(struct ahash_alg *alg)
 547 {
 548         struct crypto_alg *base = &alg->halg.base;
 549
 550         if (alg->halg.digestsize > PAGE_SIZE / 8 ||
 551             alg->halg.statesize > PAGE_SIZE / 8 ||
 552             alg->halg.statesize == 0)
 553                 return -EINVAL;
 554
 555         base->cra_type = &crypto_ahash_type;
 556         base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
 557         base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
 558
 559         return 0;
 560 }
 561
 562 int crypto_register_ahash(struct ahash_alg *alg)
 563 {
 564         struct crypto_alg *base = &alg->halg.base;
 565         int err;
 566
 567         err = ahash_prepare_alg(alg);
 568         if (err)
 569                 return err;
 570
 571         return crypto_register_alg(base);
 572 }
 573 EXPORT_SYMBOL_GPL(crypto_register_ahash);
 574
 575 int crypto_unregister_ahash(struct ahash_alg *alg)
 576 {
 577         return crypto_unregister_alg(&alg->halg.base);
 578 }
 579 EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
 580
 581 int ahash_register_instance(struct crypto_template *tmpl,
 582                             struct ahash_instance *inst)
 583 {
 584         int err;
 585
 586         err = ahash_prepare_alg(&inst->alg);
 587         if (err)
 588                 return err;
 589
 590         return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
 591 }
 592 EXPORT_SYMBOL_GPL(ahash_register_instance);
 593
 594 void ahash_free_instance(struct crypto_instance *inst)
 595 {
 596         crypto_drop_spawn(crypto_instance_ctx(inst));
 597         kfree(ahash_instance(inst));
 598 }
 599 EXPORT_SYMBOL_GPL(ahash_free_instance);
 600
 601 int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
 602                             struct hash_alg_common *alg,
 603                             struct crypto_instance *inst)
 604 {
 605         return crypto_init_spawn2(&spawn->base, &alg->base, inst,
 606                                   &crypto_ahash_type);
 607 }
 608 EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn);
 609
 610 struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
 611 {
 612         struct crypto_alg *alg;
 613
 614         alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask);
 615         return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg);
 616 }
 617 EXPORT_SYMBOL_GPL(ahash_attr_alg);
 618
 619 MODULE_LICENSE("GPL");
 620 MODULE_DESCRIPTION("Asynchronous cryptographic hash type");