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/err.h>
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21 #include <linux/sched.h>
  22 #include <linux/slab.h>
  23 #include <linux/seq_file.h>
  24 #include <linux/cryptouser.h>
  25 #include <net/netlink.h>
  26
  27 #include "internal.h"
  28
  29 struct ahash_request_priv {
  30         crypto_completion_t complete;
  31         void *data;
  32         u8 *result;
  33         void *ubuf[] CRYPTO_MINALIGN_ATTR;
  34 };
  35
  36 static inline struct ahash_alg *crypto_ahash_alg(struct crypto_ahash *hash)
  37 {
  38         return container_of(crypto_hash_alg_common(hash), struct ahash_alg,
  39                             halg);
  40 }
  41
  42 static int hash_walk_next(struct crypto_hash_walk *walk)
  43 {
  44         unsigned int alignmask = walk->alignmask;
  45         unsigned int offset = walk->offset;
  46         unsigned int nbytes = min(walk->entrylen,
  47                                   ((unsigned int)(PAGE_SIZE)) - offset);
  48
  49         walk->data = kmap_atomic(walk->pg);
  50         walk->data += offset;
  51
  52         if (offset & alignmask) {
  53                 unsigned int unaligned = alignmask + 1 - (offset & alignmask);
  54                 if (nbytes > unaligned)
  55                         nbytes = unaligned;
  56         }
  57
  58         walk->entrylen -= nbytes;
  59         return nbytes;
  60 }
  61
  62 static int hash_walk_new_entry(struct crypto_hash_walk *walk)
  63 {
  64         struct scatterlist *sg;
  65
  66         sg = walk->sg;
  67         walk->pg = sg_page(sg);
  68         walk->offset = sg->offset;
  69         walk->entrylen = sg->length;
  70
  71         if (walk->entrylen > walk->total)
  72                 walk->entrylen = walk->total;
  73         walk->total -= walk->entrylen;
  74
  75         return hash_walk_next(walk);
  76 }
  77
  78 int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
  79 {
  80         unsigned int alignmask = walk->alignmask;
  81         unsigned int nbytes = walk->entrylen;
  82
  83         walk->data -= walk->offset;
  84
  85         if (nbytes && walk->offset & alignmask && !err) {
  86                 walk->offset = ALIGN(walk->offset, alignmask + 1);
  87                 walk->data += walk->offset;
  88
  89                 nbytes = min(nbytes,
  90                              ((unsigned int)(PAGE_SIZE)) - walk->offset);
  91                 walk->entrylen -= nbytes;
  92
  93                 return nbytes;
  94         }
  95
  96         kunmap_atomic(walk->data);
  97         crypto_yield(walk->flags);
  98
  99         if (err)
 100                 return err;
 101
 102         if (nbytes) {
 103                 walk->offset = 0;
 104                 walk->pg++;
 105                 return hash_walk_next(walk);
 106         }
 107
 108         if (!walk->total)
 109                 return 0;
 110
 111         walk->sg = scatterwalk_sg_next(walk->sg);
 112
 113         return hash_walk_new_entry(walk);
 114 }
 115 EXPORT_SYMBOL_GPL(crypto_hash_walk_done);
 116
 117 int crypto_hash_walk_first(struct ahash_request *req,
 118                            struct crypto_hash_walk *walk)
 119 {
 120         walk->total = req->nbytes;
 121
 122         if (!walk->total)
 123                 return 0;
 124
 125         walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
 126         walk->sg = req->src;
 127         walk->flags = req->base.flags;
 128
 129         return hash_walk_new_entry(walk);
 130 }
 131 EXPORT_SYMBOL_GPL(crypto_hash_walk_first);
 132
 133 int crypto_hash_walk_first_compat(struct hash_desc *hdesc,
 134                                   struct crypto_hash_walk *walk,
 135                                   struct scatterlist *sg, unsigned int len)
 136 {
 137         walk->total = len;
 138
 139         if (!walk->total)
 140                 return 0;
 141
 142         walk->alignmask = crypto_hash_alignmask(hdesc->tfm);
 143         walk->sg = sg;
 144         walk->flags = hdesc->flags;
 145
 146         return hash_walk_new_entry(walk);
 147 }
 148
 149 static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,
 150                                 unsigned int keylen)
 151 {
 152         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 153         int ret;
 154         u8 *buffer, *alignbuffer;
 155         unsigned long absize;
 156
 157         absize = keylen + alignmask;
 158         buffer = kmalloc(absize, GFP_KERNEL);
 159         if (!buffer)
 160                 return -ENOMEM;
 161
 162         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 163         memcpy(alignbuffer, key, keylen);
 164         ret = tfm->setkey(tfm, alignbuffer, keylen);
 165         kzfree(buffer);
 166         return ret;
 167 }
 168
 169 int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
 170                         unsigned int keylen)
 171 {
 172         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 173
 174         if ((unsigned long)key & alignmask)
 175                 return ahash_setkey_unaligned(tfm, key, keylen);
 176
 177         return tfm->setkey(tfm, key, keylen);
 178 }
 179 EXPORT_SYMBOL_GPL(crypto_ahash_setkey);
 180
 181 static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
 182                           unsigned int keylen)
 183 {
 184         return -ENOSYS;
 185 }
 186
 187 static inline unsigned int ahash_align_buffer_size(unsigned len,
 188                                                    unsigned long mask)
 189 {
 190         return len + (mask & ~(crypto_tfm_ctx_alignment() - 1));
 191 }
 192
 193 static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt)
 194 {
 195         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 196         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 197         unsigned int ds = crypto_ahash_digestsize(tfm);
 198         struct ahash_request_priv *priv;
 199
 200         priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
 201                        (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
 202                        GFP_KERNEL : GFP_ATOMIC);
 203         if (!priv)
 204                 return -ENOMEM;
 205
 206         /*
 207          * WARNING: Voodoo programming below!
 208          *
 209          * The code below is obscure and hard to understand, thus explanation
 210          * is necessary. See include/crypto/hash.h and include/linux/crypto.h
 211          * to understand the layout of structures used here!
 212          *
 213          * The code here will replace portions of the ORIGINAL request with
 214          * pointers to new code and buffers so the hashing operation can store
 215          * the result in aligned buffer. We will call the modified request
 216          * an ADJUSTED request.
 217          *
 218          * The newly mangled request will look as such:
 219          *
 220          * req {
 221          *   .result        = ADJUSTED[new aligned buffer]
 222          *   .base.complete = ADJUSTED[pointer to completion function]
 223          *   .base.data     = ADJUSTED[*req (pointer to self)]
 224          *   .priv          = ADJUSTED[new priv] {
 225          *           .result   = ORIGINAL(result)
 226          *           .complete = ORIGINAL(base.complete)
 227          *           .data     = ORIGINAL(base.data)
 228          *   }
 229          */
 230
 231         priv->result = req->result;
 232         priv->complete = req->base.complete;
 233         priv->data = req->base.data;
 234         /*
 235          * WARNING: We do not backup req->priv here! The req->priv
 236          *          is for internal use of the Crypto API and the
 237          *          user must _NOT_ _EVER_ depend on it's content!
 238          */
 239
 240         req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
 241         req->base.complete = cplt;
 242         req->base.data = req;
 243         req->priv = priv;
 244
 245         return 0;
 246 }
 247
 248 static void ahash_restore_req(struct ahash_request *req)
 249 {
 250         struct ahash_request_priv *priv = req->priv;
 251
 252         /* Restore the original crypto request. */
 253         req->result = priv->result;
 254         req->base.complete = priv->complete;
 255         req->base.data = priv->data;
 256         req->priv = NULL;
 257
 258         /* Free the req->priv.priv from the ADJUSTED request. */
 259         kzfree(priv);
 260 }
 261
 262 static void ahash_op_unaligned_finish(struct ahash_request *req, int err)
 263 {
 264         struct ahash_request_priv *priv = req->priv;
 265
 266         if (err == -EINPROGRESS)
 267                 return;
 268
 269         if (!err)
 270                 memcpy(priv->result, req->result,
 271                        crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
 272
 273         ahash_restore_req(req);
 274 }
 275
 276 static void ahash_op_unaligned_done(struct crypto_async_request *req, int err)
 277 {
 278         struct ahash_request *areq = req->data;
 279
 280         /*
 281          * Restore the original request, see ahash_op_unaligned() for what
 282          * goes where.
 283          *
 284          * The "struct ahash_request *req" here is in fact the "req.base"
 285          * from the ADJUSTED request from ahash_op_unaligned(), thus as it
 286          * is a pointer to self, it is also the ADJUSTED "req" .
 287          */
 288
 289         /* First copy req->result into req->priv.result */
 290         ahash_op_unaligned_finish(areq, err);
 291
 292         /* Complete the ORIGINAL request. */
 293         areq->base.complete(&areq->base, err);
 294 }
 295
 296 static int ahash_op_unaligned(struct ahash_request *req,
 297                               int (*op)(struct ahash_request *))
 298 {
 299         int err;
 300
 301         err = ahash_save_req(req, ahash_op_unaligned_done);
 302         if (err)
 303                 return err;
 304
 305         err = op(req);
 306         ahash_op_unaligned_finish(req, err);
 307
 308         return err;
 309 }
 310
 311 static int crypto_ahash_op(struct ahash_request *req,
 312                            int (*op)(struct ahash_request *))
 313 {
 314         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 315         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 316
 317         if ((unsigned long)req->result & alignmask)
 318                 return ahash_op_unaligned(req, op);
 319
 320         return op(req);
 321 }
 322
 323 int crypto_ahash_final(struct ahash_request *req)
 324 {
 325         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
 326 }
 327 EXPORT_SYMBOL_GPL(crypto_ahash_final);
 328
 329 int crypto_ahash_finup(struct ahash_request *req)
 330 {
 331         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
 332 }
 333 EXPORT_SYMBOL_GPL(crypto_ahash_finup);
 334
 335 int crypto_ahash_digest(struct ahash_request *req)
 336 {
 337         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->digest);
 338 }
 339 EXPORT_SYMBOL_GPL(crypto_ahash_digest);
 340
 341 static void ahash_def_finup_finish2(struct ahash_request *req, int err)
 342 {
 343         struct ahash_request_priv *priv = req->priv;
 344
 345         if (err == -EINPROGRESS)
 346                 return;
 347
 348         if (!err)
 349                 memcpy(priv->result, req->result,
 350                        crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
 351
 352         ahash_restore_req(req);
 353 }
 354
 355 static void ahash_def_finup_done2(struct crypto_async_request *req, int err)
 356 {
 357         struct ahash_request *areq = req->data;
 358
 359         ahash_def_finup_finish2(areq, err);
 360
 361         areq->base.complete(&areq->base, err);
 362 }
 363
 364 static int ahash_def_finup_finish1(struct ahash_request *req, int err)
 365 {
 366         if (err)
 367                 goto out;
 368
 369         req->base.complete = ahash_def_finup_done2;
 370         req->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
 371         err = crypto_ahash_reqtfm(req)->final(req);
 372
 373 out:
 374         ahash_def_finup_finish2(req, err);
 375         return err;
 376 }
 377
 378 static void ahash_def_finup_done1(struct crypto_async_request *req, int err)
 379 {
 380         struct ahash_request *areq = req->data;
 381
 382         err = ahash_def_finup_finish1(areq, err);
 383
 384         areq->base.complete(&areq->base, err);
 385 }
 386
 387 static int ahash_def_finup(struct ahash_request *req)
 388 {
 389         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 390         int err;
 391
 392         err = ahash_save_req(req, ahash_def_finup_done1);
 393         if (err)
 394                 return err;
 395
 396         err = tfm->update(req);
 397         return ahash_def_finup_finish1(req, err);
 398 }
 399
 400 static int ahash_no_export(struct ahash_request *req, void *out)
 401 {
 402         return -ENOSYS;
 403 }
 404
 405 static int ahash_no_import(struct ahash_request *req, const void *in)
 406 {
 407         return -ENOSYS;
 408 }
 409
 410 static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
 411 {
 412         struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
 413         struct ahash_alg *alg = crypto_ahash_alg(hash);
 414
 415         hash->setkey = ahash_nosetkey;
 416         hash->export = ahash_no_export;
 417         hash->import = ahash_no_import;
 418
 419         if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
 420                 return crypto_init_shash_ops_async(tfm);
 421
 422         hash->init = alg->init;
 423         hash->update = alg->update;
 424         hash->final = alg->final;
 425         hash->finup = alg->finup ?: ahash_def_finup;
 426         hash->digest = alg->digest;
 427
 428         if (alg->setkey)
 429                 hash->setkey = alg->setkey;
 430         if (alg->export)
 431                 hash->export = alg->export;
 432         if (alg->import)
 433                 hash->import = alg->import;
 434
 435         return 0;
 436 }
 437
 438 static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
 439 {
 440         if (alg->cra_type == &crypto_ahash_type)
 441                 return alg->cra_ctxsize;
 442
 443         return sizeof(struct crypto_shash *);
 444 }
 445
 446 #ifdef CONFIG_NET
 447 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 448 {
 449         struct crypto_report_hash rhash;
 450
 451         strncpy(rhash.type, "ahash", sizeof(rhash.type));
 452
 453         rhash.blocksize = alg->cra_blocksize;
 454         rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
 455
 456         if (nla_put(skb, CRYPTOCFGA_REPORT_HASH,
 457                     sizeof(struct crypto_report_hash), &rhash))
 458                 goto nla_put_failure;
 459         return 0;
 460
 461 nla_put_failure:
 462         return -EMSGSIZE;
 463 }
 464 #else
 465 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 466 {
 467         return -ENOSYS;
 468 }
 469 #endif
 470
 471 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 472         __attribute__ ((unused));
 473 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 474 {
 475         seq_printf(m, "type         : ahash\n");
 476         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 477                                              "yes" : "no");
 478         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 479         seq_printf(m, "digestsize   : %u\n",
 480                    __crypto_hash_alg_common(alg)->digestsize);
 481 }
 482
 483 const struct crypto_type crypto_ahash_type = {
 484         .extsize = crypto_ahash_extsize,
 485         .init_tfm = crypto_ahash_init_tfm,
 486 #ifdef CONFIG_PROC_FS
 487         .show = crypto_ahash_show,
 488 #endif
 489         .report = crypto_ahash_report,
 490         .maskclear = ~CRYPTO_ALG_TYPE_MASK,
 491         .maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
 492         .type = CRYPTO_ALG_TYPE_AHASH,
 493         .tfmsize = offsetof(struct crypto_ahash, base),
 494 };
 495 EXPORT_SYMBOL_GPL(crypto_ahash_type);
 496
 497 struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
 498                                         u32 mask)
 499 {
 500         return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
 501 }
 502 EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
 503
 504 static int ahash_prepare_alg(struct ahash_alg *alg)
 505 {
 506         struct crypto_alg *base = &alg->halg.base;
 507
 508         if (alg->halg.digestsize > PAGE_SIZE / 8 ||
 509             alg->halg.statesize > PAGE_SIZE / 8)
 510                 return -EINVAL;
 511
 512         base->cra_type = &crypto_ahash_type;
 513         base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
 514         base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
 515
 516         return 0;
 517 }
 518
 519 int crypto_register_ahash(struct ahash_alg *alg)
 520 {
 521         struct crypto_alg *base = &alg->halg.base;
 522         int err;
 523
 524         err = ahash_prepare_alg(alg);
 525         if (err)
 526                 return err;
 527
 528         return crypto_register_alg(base);
 529 }
 530 EXPORT_SYMBOL_GPL(crypto_register_ahash);
 531
 532 int crypto_unregister_ahash(struct ahash_alg *alg)
 533 {
 534         return crypto_unregister_alg(&alg->halg.base);
 535 }
 536 EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
 537
 538 int ahash_register_instance(struct crypto_template *tmpl,
 539                             struct ahash_instance *inst)
 540 {
 541         int err;
 542
 543         err = ahash_prepare_alg(&inst->alg);
 544         if (err)
 545                 return err;
 546
 547         return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
 548 }
 549 EXPORT_SYMBOL_GPL(ahash_register_instance);
 550
 551 void ahash_free_instance(struct crypto_instance *inst)
 552 {
 553         crypto_drop_spawn(crypto_instance_ctx(inst));
 554         kfree(ahash_instance(inst));
 555 }
 556 EXPORT_SYMBOL_GPL(ahash_free_instance);
 557
 558 int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
 559                             struct hash_alg_common *alg,
 560                             struct crypto_instance *inst)
 561 {
 562         return crypto_init_spawn2(&spawn->base, &alg->base, inst,
 563                                   &crypto_ahash_type);
 564 }
 565 EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn);
 566
 567 struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
 568 {
 569         struct crypto_alg *alg;
 570
 571         alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask);
 572         return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg);
 573 }
 574 EXPORT_SYMBOL_GPL(ahash_attr_alg);
 575
 576 MODULE_LICENSE("GPL");
 577 MODULE_DESCRIPTION("Asynchronous cryptographic hash type");