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         u32 flags;
  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         walk->data = crypto_kmap(walk->pg, 0);
  51         walk->data += offset;
  52
  53         if (offset & alignmask) {
  54                 unsigned int unaligned = alignmask + 1 - (offset & alignmask);
  55                 if (nbytes > unaligned)
  56                         nbytes = unaligned;
  57         }
  58
  59         walk->entrylen -= nbytes;
  60         return nbytes;
  61 }
  62
  63 static int hash_walk_new_entry(struct crypto_hash_walk *walk)
  64 {
  65         struct scatterlist *sg;
  66
  67         sg = walk->sg;
  68         walk->offset = sg->offset;
  69         walk->pg = sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
  70         walk->offset = offset_in_page(walk->offset);
  71         walk->entrylen = sg->length;
  72
  73         if (walk->entrylen > walk->total)
  74                 walk->entrylen = walk->total;
  75         walk->total -= walk->entrylen;
  76
  77         return hash_walk_next(walk);
  78 }
  79
  80 int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
  81 {
  82         unsigned int alignmask = walk->alignmask;
  83         unsigned int nbytes = walk->entrylen;
  84
  85         walk->data -= walk->offset;
  86
  87         if (nbytes && walk->offset & alignmask && !err) {
  88                 walk->offset = ALIGN(walk->offset, alignmask + 1);
  89                 walk->data += walk->offset;
  90
  91                 nbytes = min(nbytes,
  92                              ((unsigned int)(PAGE_SIZE)) - walk->offset);
  93                 walk->entrylen -= nbytes;
  94
  95                 return nbytes;
  96         }
  97
  98         crypto_kunmap(walk->data, 0);
  99         crypto_yield(walk->flags);
 100
 101         if (err)
 102                 return err;
 103
 104         if (nbytes) {
 105                 walk->offset = 0;
 106                 walk->pg++;
 107                 return hash_walk_next(walk);
 108         }
 109
 110         if (!walk->total)
 111                 return 0;
 112
 113         walk->sg = scatterwalk_sg_next(walk->sg);
 114
 115         return hash_walk_new_entry(walk);
 116 }
 117 EXPORT_SYMBOL_GPL(crypto_hash_walk_done);
 118
 119 int crypto_hash_walk_first(struct ahash_request *req,
 120                            struct crypto_hash_walk *walk)
 121 {
 122         walk->total = req->nbytes;
 123
 124         if (!walk->total)
 125                 return 0;
 126
 127         walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
 128         walk->sg = req->src;
 129         walk->flags = req->base.flags;
 130
 131         return hash_walk_new_entry(walk);
 132 }
 133 EXPORT_SYMBOL_GPL(crypto_hash_walk_first);
 134
 135 int crypto_hash_walk_first_compat(struct hash_desc *hdesc,
 136                                   struct crypto_hash_walk *walk,
 137                                   struct scatterlist *sg, unsigned int len)
 138 {
 139         walk->total = len;
 140
 141         if (!walk->total)
 142                 return 0;
 143
 144         walk->alignmask = crypto_hash_alignmask(hdesc->tfm);
 145         walk->sg = sg;
 146         walk->flags = hdesc->flags;
 147
 148         return hash_walk_new_entry(walk);
 149 }
 150
 151 static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,
 152                                 unsigned int keylen)
 153 {
 154         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 155         int ret;
 156         u8 *buffer, *alignbuffer;
 157         unsigned long absize;
 158
 159         absize = keylen + alignmask;
 160         buffer = kmalloc(absize, GFP_KERNEL);
 161         if (!buffer)
 162                 return -ENOMEM;
 163
 164         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 165         memcpy(alignbuffer, key, keylen);
 166         ret = tfm->setkey(tfm, alignbuffer, keylen);
 167         kzfree(buffer);
 168         return ret;
 169 }
 170
 171 int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
 172                         unsigned int keylen)
 173 {
 174         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 175
 176         if ((unsigned long)key & alignmask)
 177                 return ahash_setkey_unaligned(tfm, key, keylen);
 178
 179         return tfm->setkey(tfm, key, keylen);
 180 }
 181 EXPORT_SYMBOL_GPL(crypto_ahash_setkey);
 182
 183 static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
 184                           unsigned int keylen)
 185 {
 186         return -ENOSYS;
 187 }
 188
 189 static inline unsigned int ahash_align_buffer_size(unsigned len,
 190                                                    unsigned long mask)
 191 {
 192         return len + (mask & ~(crypto_tfm_ctx_alignment() - 1));
 193 }
 194
 195 static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt)
 196 {
 197         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 198         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 199         unsigned int ds = crypto_ahash_digestsize(tfm);
 200         struct ahash_request_priv *priv;
 201
 202         priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
 203                        (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
 204                        GFP_KERNEL : GFP_ATOMIC);
 205         if (!priv)
 206                 return -ENOMEM;
 207
 208         /*
 209          * WARNING: Voodoo programming below!
 210          *
 211          * The code below is obscure and hard to understand, thus explanation
 212          * is necessary. See include/crypto/hash.h and include/linux/crypto.h
 213          * to understand the layout of structures used here!
 214          *
 215          * The code here will replace portions of the ORIGINAL request with
 216          * pointers to new code and buffers so the hashing operation can store
 217          * the result in aligned buffer. We will call the modified request
 218          * an ADJUSTED request.
 219          *
 220          * The newly mangled request will look as such:
 221          *
 222          * req {
 223          *   .result        = ADJUSTED[new aligned buffer]
 224          *   .base.complete = ADJUSTED[pointer to completion function]
 225          *   .base.data     = ADJUSTED[*req (pointer to self)]
 226          *   .priv          = ADJUSTED[new priv] {
 227          *           .result   = ORIGINAL(result)
 228          *           .complete = ORIGINAL(base.complete)
 229          *           .data     = ORIGINAL(base.data)
 230          *   }
 231          */
 232
 233         priv->result = req->result;
 234         priv->complete = req->base.complete;
 235         priv->data = req->base.data;
 236         priv->flags = req->base.flags;
 237
 238         /*
 239          * WARNING: We do not backup req->priv here! The req->priv
 240          *          is for internal use of the Crypto API and the
 241          *          user must _NOT_ _EVER_ depend on it's content!
 242          */
 243
 244         req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
 245         req->base.complete = cplt;
 246         req->base.data = req;
 247         req->priv = priv;
 248
 249         return 0;
 250 }
 251
 252 static void ahash_restore_req(struct ahash_request *req, int err)
 253 {
 254         struct ahash_request_priv *priv = req->priv;
 255
 256         if (!err)
 257                 memcpy(priv->result, req->result,
 258                        crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
 259
 260         /* Restore the original crypto request. */
 261         req->result = priv->result;
 262
 263         ahash_request_set_callback(req, priv->flags,
 264                                    priv->complete, priv->data);
 265         req->priv = NULL;
 266
 267         /* Free the req->priv.priv from the ADJUSTED request. */
 268         kzfree(priv);
 269 }
 270
 271 static void ahash_notify_einprogress(struct ahash_request *req)
 272 {
 273         struct ahash_request_priv *priv = req->priv;
 274         struct crypto_async_request oreq;
 275
 276         oreq.data = priv->data;
 277
 278         priv->complete(&oreq, -EINPROGRESS);
 279 }
 280
 281 static void ahash_op_unaligned_done(struct crypto_async_request *req, int err)
 282 {
 283         struct ahash_request *areq = req->data;
 284
 285         if (err == -EINPROGRESS) {
 286                 ahash_notify_einprogress(areq);
 287                 return;
 288         }
 289
 290         /*
 291          * Restore the original request, see ahash_op_unaligned() for what
 292          * goes where.
 293          *
 294          * The "struct ahash_request *req" here is in fact the "req.base"
 295          * from the ADJUSTED request from ahash_op_unaligned(), thus as it
 296          * is a pointer to self, it is also the ADJUSTED "req" .
 297          */
 298
 299         /* First copy req->result into req->priv.result */
 300         ahash_restore_req(areq, err);
 301
 302         /* Complete the ORIGINAL request. */
 303         areq->base.complete(&areq->base, err);
 304 }
 305
 306 static int ahash_op_unaligned(struct ahash_request *req,
 307                               int (*op)(struct ahash_request *))
 308 {
 309         int err;
 310
 311         err = ahash_save_req(req, ahash_op_unaligned_done);
 312         if (err)
 313                 return err;
 314
 315         err = op(req);
 316         if (err == -EINPROGRESS ||
 317             (err == -EBUSY && (ahash_request_flags(req) &
 318                                CRYPTO_TFM_REQ_MAY_BACKLOG)))
 319                 return err;
 320
 321         ahash_restore_req(req, err);
 322
 323         return err;
 324 }
 325
 326 static int crypto_ahash_op(struct ahash_request *req,
 327                            int (*op)(struct ahash_request *))
 328 {
 329         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 330         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 331
 332         if ((unsigned long)req->result & alignmask)
 333                 return ahash_op_unaligned(req, op);
 334
 335         return op(req);
 336 }
 337
 338 int crypto_ahash_final(struct ahash_request *req)
 339 {
 340         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
 341 }
 342 EXPORT_SYMBOL_GPL(crypto_ahash_final);
 343
 344 int crypto_ahash_finup(struct ahash_request *req)
 345 {
 346         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
 347 }
 348 EXPORT_SYMBOL_GPL(crypto_ahash_finup);
 349
 350 int crypto_ahash_digest(struct ahash_request *req)
 351 {
 352         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->digest);
 353 }
 354 EXPORT_SYMBOL_GPL(crypto_ahash_digest);
 355
 356 static void ahash_def_finup_done2(struct crypto_async_request *req, int err)
 357 {
 358         struct ahash_request *areq = req->data;
 359
 360         if (err == -EINPROGRESS)
 361                 return;
 362
 363         ahash_restore_req(areq, err);
 364
 365         areq->base.complete(&areq->base, err);
 366 }
 367
 368 static int ahash_def_finup_finish1(struct ahash_request *req, int err)
 369 {
 370         if (err)
 371                 goto out;
 372
 373         req->base.complete = ahash_def_finup_done2;
 374
 375         err = crypto_ahash_reqtfm(req)->final(req);
 376         if (err == -EINPROGRESS ||
 377             (err == -EBUSY && (ahash_request_flags(req) &
 378                                CRYPTO_TFM_REQ_MAY_BACKLOG)))
 379                 return err;
 380
 381 out:
 382         ahash_restore_req(req, err);
 383         return err;
 384 }
 385
 386 static void ahash_def_finup_done1(struct crypto_async_request *req, int err)
 387 {
 388         struct ahash_request *areq = req->data;
 389
 390         if (err == -EINPROGRESS) {
 391                 ahash_notify_einprogress(areq);
 392                 return;
 393         }
 394
 395         areq->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
 396
 397         err = ahash_def_finup_finish1(areq, err);
 398         if (areq->priv)
 399                 return;
 400
 401         areq->base.complete(&areq->base, err);
 402 }
 403
 404 static int ahash_def_finup(struct ahash_request *req)
 405 {
 406         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 407         int err;
 408
 409         err = ahash_save_req(req, ahash_def_finup_done1);
 410         if (err)
 411                 return err;
 412
 413         err = tfm->update(req);
 414         if (err == -EINPROGRESS ||
 415             (err == -EBUSY && (ahash_request_flags(req) &
 416                                CRYPTO_TFM_REQ_MAY_BACKLOG)))
 417                 return err;
 418
 419         return ahash_def_finup_finish1(req, err);
 420 }
 421
 422 static int ahash_no_export(struct ahash_request *req, void *out)
 423 {
 424         return -ENOSYS;
 425 }
 426
 427 static int ahash_no_import(struct ahash_request *req, const void *in)
 428 {
 429         return -ENOSYS;
 430 }
 431
 432 static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
 433 {
 434         struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
 435         struct ahash_alg *alg = crypto_ahash_alg(hash);
 436
 437         hash->setkey = ahash_nosetkey;
 438         hash->has_setkey = false;
 439         hash->export = ahash_no_export;
 440         hash->import = ahash_no_import;
 441
 442         if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
 443                 return crypto_init_shash_ops_async(tfm);
 444
 445         hash->init = alg->init;
 446         hash->update = alg->update;
 447         hash->final = alg->final;
 448         hash->finup = alg->finup ?: ahash_def_finup;
 449         hash->digest = alg->digest;
 450
 451         if (alg->setkey) {
 452                 hash->setkey = alg->setkey;
 453                 hash->has_setkey = true;
 454         }
 455         if (alg->export)
 456                 hash->export = alg->export;
 457         if (alg->import)
 458                 hash->import = alg->import;
 459
 460         return 0;
 461 }
 462
 463 static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
 464 {
 465         if (alg->cra_type == &crypto_ahash_type)
 466                 return alg->cra_ctxsize;
 467
 468         return sizeof(struct crypto_shash *);
 469 }
 470
 471 #ifdef CONFIG_NET
 472 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 473 {
 474         struct crypto_report_hash rhash;
 475
 476         strncpy(rhash.type, "ahash", sizeof(rhash.type));
 477
 478         rhash.blocksize = alg->cra_blocksize;
 479         rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
 480
 481         NLA_PUT(skb, CRYPTOCFGA_REPORT_HASH,
 482                 sizeof(struct crypto_report_hash), &rhash);
 483
 484         return 0;
 485
 486 nla_put_failure:
 487         return -EMSGSIZE;
 488 }
 489 #else
 490 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 491 {
 492         return -ENOSYS;
 493 }
 494 #endif
 495
 496 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 497         __attribute__ ((unused));
 498 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 499 {
 500         seq_printf(m, "type         : ahash\n");
 501         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 502                                              "yes" : "no");
 503         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 504         seq_printf(m, "digestsize   : %u\n",
 505                    __crypto_hash_alg_common(alg)->digestsize);
 506 }
 507
 508 const struct crypto_type crypto_ahash_type = {
 509         .extsize = crypto_ahash_extsize,
 510         .init_tfm = crypto_ahash_init_tfm,
 511 #ifdef CONFIG_PROC_FS
 512         .show = crypto_ahash_show,
 513 #endif
 514         .report = crypto_ahash_report,
 515         .maskclear = ~CRYPTO_ALG_TYPE_MASK,
 516         .maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
 517         .type = CRYPTO_ALG_TYPE_AHASH,
 518         .tfmsize = offsetof(struct crypto_ahash, base),
 519 };
 520 EXPORT_SYMBOL_GPL(crypto_ahash_type);
 521
 522 struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
 523                                         u32 mask)
 524 {
 525         return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
 526 }
 527 EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
 528
 529 static int ahash_prepare_alg(struct ahash_alg *alg)
 530 {
 531         struct crypto_alg *base = &alg->halg.base;
 532
 533         if (alg->halg.digestsize > PAGE_SIZE / 8 ||
 534             alg->halg.statesize > PAGE_SIZE / 8 ||
 535             alg->halg.statesize == 0)
 536                 return -EINVAL;
 537
 538         base->cra_type = &crypto_ahash_type;
 539         base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
 540         base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
 541
 542         return 0;
 543 }
 544
 545 int crypto_register_ahash(struct ahash_alg *alg)
 546 {
 547         struct crypto_alg *base = &alg->halg.base;
 548         int err;
 549
 550         err = ahash_prepare_alg(alg);
 551         if (err)
 552                 return err;
 553
 554         return crypto_register_alg(base);
 555 }
 556 EXPORT_SYMBOL_GPL(crypto_register_ahash);
 557
 558 int crypto_unregister_ahash(struct ahash_alg *alg)
 559 {
 560         return crypto_unregister_alg(&alg->halg.base);
 561 }
 562 EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
 563
 564 int ahash_register_instance(struct crypto_template *tmpl,
 565                             struct ahash_instance *inst)
 566 {
 567         int err;
 568
 569         err = ahash_prepare_alg(&inst->alg);
 570         if (err)
 571                 return err;
 572
 573         return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
 574 }
 575 EXPORT_SYMBOL_GPL(ahash_register_instance);
 576
 577 void ahash_free_instance(struct crypto_instance *inst)
 578 {
 579         crypto_drop_spawn(crypto_instance_ctx(inst));
 580         kfree(ahash_instance(inst));
 581 }
 582 EXPORT_SYMBOL_GPL(ahash_free_instance);
 583
 584 int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
 585                             struct hash_alg_common *alg,
 586                             struct crypto_instance *inst)
 587 {
 588         return crypto_init_spawn2(&spawn->base, &alg->base, inst,
 589                                   &crypto_ahash_type);
 590 }
 591 EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn);
 592
 593 struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
 594 {
 595         struct crypto_alg *alg;
 596
 597         alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask);
 598         return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg);
 599 }
 600 EXPORT_SYMBOL_GPL(ahash_attr_alg);
 601
 602 MODULE_LICENSE("GPL");
 603 MODULE_DESCRIPTION("Asynchronous cryptographic hash type");