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         int err;
 176
 177         if ((unsigned long)key & alignmask)
 178                 err = ahash_setkey_unaligned(tfm, key, keylen);
 179         else
 180                 err = tfm->setkey(tfm, key, keylen);
 181
 182         if (err)
 183                 return err;
 184
 185         crypto_ahash_clear_flags(tfm, CRYPTO_TFM_NEED_KEY);
 186         return 0;
 187 }
 188 EXPORT_SYMBOL_GPL(crypto_ahash_setkey);
 189
 190 static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
 191                           unsigned int keylen)
 192 {
 193         return -ENOSYS;
 194 }
 195
 196 static inline unsigned int ahash_align_buffer_size(unsigned len,
 197                                                    unsigned long mask)
 198 {
 199         return len + (mask & ~(crypto_tfm_ctx_alignment() - 1));
 200 }
 201
 202 static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt)
 203 {
 204         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 205         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 206         unsigned int ds = crypto_ahash_digestsize(tfm);
 207         struct ahash_request_priv *priv;
 208
 209         priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
 210                        (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
 211                        GFP_KERNEL : GFP_ATOMIC);
 212         if (!priv)
 213                 return -ENOMEM;
 214
 215         /*
 216          * WARNING: Voodoo programming below!
 217          *
 218          * The code below is obscure and hard to understand, thus explanation
 219          * is necessary. See include/crypto/hash.h and include/linux/crypto.h
 220          * to understand the layout of structures used here!
 221          *
 222          * The code here will replace portions of the ORIGINAL request with
 223          * pointers to new code and buffers so the hashing operation can store
 224          * the result in aligned buffer. We will call the modified request
 225          * an ADJUSTED request.
 226          *
 227          * The newly mangled request will look as such:
 228          *
 229          * req {
 230          *   .result        = ADJUSTED[new aligned buffer]
 231          *   .base.complete = ADJUSTED[pointer to completion function]
 232          *   .base.data     = ADJUSTED[*req (pointer to self)]
 233          *   .priv          = ADJUSTED[new priv] {
 234          *           .result   = ORIGINAL(result)
 235          *           .complete = ORIGINAL(base.complete)
 236          *           .data     = ORIGINAL(base.data)
 237          *   }
 238          */
 239
 240         priv->result = req->result;
 241         priv->complete = req->base.complete;
 242         priv->data = req->base.data;
 243         priv->flags = req->base.flags;
 244
 245         /*
 246          * WARNING: We do not backup req->priv here! The req->priv
 247          *          is for internal use of the Crypto API and the
 248          *          user must _NOT_ _EVER_ depend on it's content!
 249          */
 250
 251         req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
 252         req->base.complete = cplt;
 253         req->base.data = req;
 254         req->priv = priv;
 255
 256         return 0;
 257 }
 258
 259 static void ahash_restore_req(struct ahash_request *req, int err)
 260 {
 261         struct ahash_request_priv *priv = req->priv;
 262
 263         if (!err)
 264                 memcpy(priv->result, req->result,
 265                        crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
 266
 267         /* Restore the original crypto request. */
 268         req->result = priv->result;
 269
 270         ahash_request_set_callback(req, priv->flags,
 271                                    priv->complete, priv->data);
 272         req->priv = NULL;
 273
 274         /* Free the req->priv.priv from the ADJUSTED request. */
 275         kzfree(priv);
 276 }
 277
 278 static void ahash_notify_einprogress(struct ahash_request *req)
 279 {
 280         struct ahash_request_priv *priv = req->priv;
 281         struct crypto_async_request oreq;
 282
 283         oreq.data = priv->data;
 284
 285         priv->complete(&oreq, -EINPROGRESS);
 286 }
 287
 288 static void ahash_op_unaligned_done(struct crypto_async_request *req, int err)
 289 {
 290         struct ahash_request *areq = req->data;
 291
 292         if (err == -EINPROGRESS) {
 293                 ahash_notify_einprogress(areq);
 294                 return;
 295         }
 296
 297         /*
 298          * Restore the original request, see ahash_op_unaligned() for what
 299          * goes where.
 300          *
 301          * The "struct ahash_request *req" here is in fact the "req.base"
 302          * from the ADJUSTED request from ahash_op_unaligned(), thus as it
 303          * is a pointer to self, it is also the ADJUSTED "req" .
 304          */
 305
 306         /* First copy req->result into req->priv.result */
 307         ahash_restore_req(areq, err);
 308
 309         /* Complete the ORIGINAL request. */
 310         areq->base.complete(&areq->base, err);
 311 }
 312
 313 static int ahash_op_unaligned(struct ahash_request *req,
 314                               int (*op)(struct ahash_request *))
 315 {
 316         int err;
 317
 318         err = ahash_save_req(req, ahash_op_unaligned_done);
 319         if (err)
 320                 return err;
 321
 322         err = op(req);
 323         if (err == -EINPROGRESS ||
 324             (err == -EBUSY && (ahash_request_flags(req) &
 325                                CRYPTO_TFM_REQ_MAY_BACKLOG)))
 326                 return err;
 327
 328         ahash_restore_req(req, err);
 329
 330         return err;
 331 }
 332
 333 static int crypto_ahash_op(struct ahash_request *req,
 334                            int (*op)(struct ahash_request *))
 335 {
 336         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 337         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 338
 339         if ((unsigned long)req->result & alignmask)
 340                 return ahash_op_unaligned(req, op);
 341
 342         return op(req);
 343 }
 344
 345 int crypto_ahash_final(struct ahash_request *req)
 346 {
 347         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
 348 }
 349 EXPORT_SYMBOL_GPL(crypto_ahash_final);
 350
 351 int crypto_ahash_finup(struct ahash_request *req)
 352 {
 353         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
 354 }
 355 EXPORT_SYMBOL_GPL(crypto_ahash_finup);
 356
 357 int crypto_ahash_digest(struct ahash_request *req)
 358 {
 359         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 360
 361         if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
 362                 return -ENOKEY;
 363
 364         return crypto_ahash_op(req, tfm->digest);
 365 }
 366 EXPORT_SYMBOL_GPL(crypto_ahash_digest);
 367
 368 static void ahash_def_finup_done2(struct crypto_async_request *req, int err)
 369 {
 370         struct ahash_request *areq = req->data;
 371
 372         if (err == -EINPROGRESS)
 373                 return;
 374
 375         ahash_restore_req(areq, err);
 376
 377         areq->base.complete(&areq->base, err);
 378 }
 379
 380 static int ahash_def_finup_finish1(struct ahash_request *req, int err)
 381 {
 382         if (err)
 383                 goto out;
 384
 385         req->base.complete = ahash_def_finup_done2;
 386
 387         err = crypto_ahash_reqtfm(req)->final(req);
 388         if (err == -EINPROGRESS ||
 389             (err == -EBUSY && (ahash_request_flags(req) &
 390                                CRYPTO_TFM_REQ_MAY_BACKLOG)))
 391                 return err;
 392
 393 out:
 394         ahash_restore_req(req, err);
 395         return err;
 396 }
 397
 398 static void ahash_def_finup_done1(struct crypto_async_request *req, int err)
 399 {
 400         struct ahash_request *areq = req->data;
 401
 402         if (err == -EINPROGRESS) {
 403                 ahash_notify_einprogress(areq);
 404                 return;
 405         }
 406
 407         areq->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
 408
 409         err = ahash_def_finup_finish1(areq, err);
 410         if (areq->priv)
 411                 return;
 412
 413         areq->base.complete(&areq->base, err);
 414 }
 415
 416 static int ahash_def_finup(struct ahash_request *req)
 417 {
 418         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 419         int err;
 420
 421         err = ahash_save_req(req, ahash_def_finup_done1);
 422         if (err)
 423                 return err;
 424
 425         err = tfm->update(req);
 426         if (err == -EINPROGRESS ||
 427             (err == -EBUSY && (ahash_request_flags(req) &
 428                                CRYPTO_TFM_REQ_MAY_BACKLOG)))
 429                 return err;
 430
 431         return ahash_def_finup_finish1(req, err);
 432 }
 433
 434 static int ahash_no_export(struct ahash_request *req, void *out)
 435 {
 436         return -ENOSYS;
 437 }
 438
 439 static int ahash_no_import(struct ahash_request *req, const void *in)
 440 {
 441         return -ENOSYS;
 442 }
 443
 444 static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
 445 {
 446         struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
 447         struct ahash_alg *alg = crypto_ahash_alg(hash);
 448
 449         hash->setkey = ahash_nosetkey;
 450         hash->export = ahash_no_export;
 451         hash->import = ahash_no_import;
 452
 453         if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
 454                 return crypto_init_shash_ops_async(tfm);
 455
 456         hash->init = alg->init;
 457         hash->update = alg->update;
 458         hash->final = alg->final;
 459         hash->finup = alg->finup ?: ahash_def_finup;
 460         hash->digest = alg->digest;
 461
 462         if (alg->setkey) {
 463                 hash->setkey = alg->setkey;
 464                 if (!(alg->halg.base.cra_flags & CRYPTO_ALG_OPTIONAL_KEY))
 465                         crypto_ahash_set_flags(hash, CRYPTO_TFM_NEED_KEY);
 466         }
 467         if (alg->export)
 468                 hash->export = alg->export;
 469         if (alg->import)
 470                 hash->import = alg->import;
 471
 472         return 0;
 473 }
 474
 475 static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
 476 {
 477         if (alg->cra_type == &crypto_ahash_type)
 478                 return alg->cra_ctxsize;
 479
 480         return sizeof(struct crypto_shash *);
 481 }
 482
 483 #ifdef CONFIG_NET
 484 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 485 {
 486         struct crypto_report_hash rhash;
 487
 488         strncpy(rhash.type, "ahash", sizeof(rhash.type));
 489
 490         rhash.blocksize = alg->cra_blocksize;
 491         rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
 492
 493         NLA_PUT(skb, CRYPTOCFGA_REPORT_HASH,
 494                 sizeof(struct crypto_report_hash), &rhash);
 495
 496         return 0;
 497
 498 nla_put_failure:
 499         return -EMSGSIZE;
 500 }
 501 #else
 502 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 503 {
 504         return -ENOSYS;
 505 }
 506 #endif
 507
 508 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 509         __attribute__ ((unused));
 510 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 511 {
 512         seq_printf(m, "type         : ahash\n");
 513         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 514                                              "yes" : "no");
 515         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 516         seq_printf(m, "digestsize   : %u\n",
 517                    __crypto_hash_alg_common(alg)->digestsize);
 518 }
 519
 520 const struct crypto_type crypto_ahash_type = {
 521         .extsize = crypto_ahash_extsize,
 522         .init_tfm = crypto_ahash_init_tfm,
 523 #ifdef CONFIG_PROC_FS
 524         .show = crypto_ahash_show,
 525 #endif
 526         .report = crypto_ahash_report,
 527         .maskclear = ~CRYPTO_ALG_TYPE_MASK,
 528         .maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
 529         .type = CRYPTO_ALG_TYPE_AHASH,
 530         .tfmsize = offsetof(struct crypto_ahash, base),
 531 };
 532 EXPORT_SYMBOL_GPL(crypto_ahash_type);
 533
 534 struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
 535                                         u32 mask)
 536 {
 537         return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
 538 }
 539 EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
 540
 541 static int ahash_prepare_alg(struct ahash_alg *alg)
 542 {
 543         struct crypto_alg *base = &alg->halg.base;
 544
 545         if (alg->halg.digestsize > PAGE_SIZE / 8 ||
 546             alg->halg.statesize > PAGE_SIZE / 8 ||
 547             alg->halg.statesize == 0)
 548                 return -EINVAL;
 549
 550         base->cra_type = &crypto_ahash_type;
 551         base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
 552         base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
 553
 554         return 0;
 555 }
 556
 557 int crypto_register_ahash(struct ahash_alg *alg)
 558 {
 559         struct crypto_alg *base = &alg->halg.base;
 560         int err;
 561
 562         err = ahash_prepare_alg(alg);
 563         if (err)
 564                 return err;
 565
 566         return crypto_register_alg(base);
 567 }
 568 EXPORT_SYMBOL_GPL(crypto_register_ahash);
 569
 570 int crypto_unregister_ahash(struct ahash_alg *alg)
 571 {
 572         return crypto_unregister_alg(&alg->halg.base);
 573 }
 574 EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
 575
 576 int ahash_register_instance(struct crypto_template *tmpl,
 577                             struct ahash_instance *inst)
 578 {
 579         int err;
 580
 581         err = ahash_prepare_alg(&inst->alg);
 582         if (err)
 583                 return err;
 584
 585         return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
 586 }
 587 EXPORT_SYMBOL_GPL(ahash_register_instance);
 588
 589 void ahash_free_instance(struct crypto_instance *inst)
 590 {
 591         crypto_drop_spawn(crypto_instance_ctx(inst));
 592         kfree(ahash_instance(inst));
 593 }
 594 EXPORT_SYMBOL_GPL(ahash_free_instance);
 595
 596 int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
 597                             struct hash_alg_common *alg,
 598                             struct crypto_instance *inst)
 599 {
 600         return crypto_init_spawn2(&spawn->base, &alg->base, inst,
 601                                   &crypto_ahash_type);
 602 }
 603 EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn);
 604
 605 struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
 606 {
 607         struct crypto_alg *alg;
 608
 609         alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask);
 610         return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg);
 611 }
 612 EXPORT_SYMBOL_GPL(ahash_attr_alg);
 613
 614 bool crypto_hash_alg_has_setkey(struct hash_alg_common *halg)
 615 {
 616         struct crypto_alg *alg = &halg->base;
 617
 618         if (alg->cra_type != &crypto_ahash_type)
 619                 return crypto_shash_alg_has_setkey(__crypto_shash_alg(alg));
 620
 621         return __crypto_ahash_alg(alg)->setkey != NULL;
 622 }
 623 EXPORT_SYMBOL_GPL(crypto_hash_alg_has_setkey);
 624
 625 MODULE_LICENSE("GPL");
 626 MODULE_DESCRIPTION("Asynchronous cryptographic hash type");