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 void ahash_op_unaligned_finish(struct ahash_request *req, int err)
 194 {
 195         struct ahash_request_priv *priv = req->priv;
 196
 197         if (err == -EINPROGRESS)
 198                 return;
 199
 200         if (!err)
 201                 memcpy(priv->result, req->result,
 202                        crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
 203
 204         /* Restore the original crypto request. */
 205         req->result = priv->result;
 206         req->base.complete = priv->complete;
 207         req->base.data = priv->data;
 208         req->priv = NULL;
 209
 210         /* Free the req->priv.priv from the ADJUSTED request. */
 211         kzfree(priv);
 212 }
 213
 214 static void ahash_op_unaligned_done(struct crypto_async_request *req, int err)
 215 {
 216         struct ahash_request *areq = req->data;
 217
 218         /*
 219          * Restore the original request, see ahash_op_unaligned() for what
 220          * goes where.
 221          *
 222          * The "struct ahash_request *req" here is in fact the "req.base"
 223          * from the ADJUSTED request from ahash_op_unaligned(), thus as it
 224          * is a pointer to self, it is also the ADJUSTED "req" .
 225          */
 226
 227         /* First copy areq->result into areq->priv.result */
 228         ahash_op_unaligned_finish(areq, err);
 229
 230         /* Complete the ORIGINAL request. */
 231         areq->base.complete(&areq->base, err);
 232 }
 233
 234 static int ahash_op_unaligned(struct ahash_request *req,
 235                               int (*op)(struct ahash_request *))
 236 {
 237         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 238         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 239         unsigned int ds = crypto_ahash_digestsize(tfm);
 240         struct ahash_request_priv *priv;
 241         int err;
 242
 243         priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
 244                        (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
 245                        GFP_KERNEL : GFP_ATOMIC);
 246         if (!priv)
 247                 return -ENOMEM;
 248
 249         /*
 250          * WARNING: Voodoo programming below!
 251          *
 252          * The code below is obscure and hard to understand, thus explanation
 253          * is necessary. See include/crypto/hash.h and include/linux/crypto.h
 254          * to understand the layout of structures used here!
 255          *
 256          * The code here will replace portions of the ORIGINAL request with
 257          * pointers to new code and buffers so the hashing operation can store
 258          * the result in aligned buffer. We will call the modified request
 259          * an ADJUSTED request.
 260          *
 261          * The newly mangled request will look as such:
 262          *
 263          * req {
 264          *   .result        = ADJUSTED[new aligned buffer]
 265          *   .base.complete = ADJUSTED[pointer to completion function]
 266          *   .base.data     = ADJUSTED[*req (pointer to self)]
 267          *   .priv          = ADJUSTED[new priv] {
 268          *           .result   = ORIGINAL(result)
 269          *           .complete = ORIGINAL(base.complete)
 270          *           .data     = ORIGINAL(base.data)
 271          *   }
 272          */
 273
 274         priv->result = req->result;
 275         priv->complete = req->base.complete;
 276         priv->data = req->base.data;
 277         /*
 278          * WARNING: We do not backup req->priv here! The req->priv
 279          *          is for internal use of the Crypto API and the
 280          *          user must _NOT_ _EVER_ depend on it's content!
 281          */
 282
 283         req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
 284         req->base.complete = ahash_op_unaligned_done;
 285         req->base.data = req;
 286         req->priv = priv;
 287
 288         err = op(req);
 289         ahash_op_unaligned_finish(req, err);
 290
 291         return err;
 292 }
 293
 294 static int crypto_ahash_op(struct ahash_request *req,
 295                            int (*op)(struct ahash_request *))
 296 {
 297         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 298         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 299
 300         if ((unsigned long)req->result & alignmask)
 301                 return ahash_op_unaligned(req, op);
 302
 303         return op(req);
 304 }
 305
 306 int crypto_ahash_final(struct ahash_request *req)
 307 {
 308         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
 309 }
 310 EXPORT_SYMBOL_GPL(crypto_ahash_final);
 311
 312 int crypto_ahash_finup(struct ahash_request *req)
 313 {
 314         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
 315 }
 316 EXPORT_SYMBOL_GPL(crypto_ahash_finup);
 317
 318 int crypto_ahash_digest(struct ahash_request *req)
 319 {
 320         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->digest);
 321 }
 322 EXPORT_SYMBOL_GPL(crypto_ahash_digest);
 323
 324 static void ahash_def_finup_finish2(struct ahash_request *req, int err)
 325 {
 326         struct ahash_request_priv *priv = req->priv;
 327
 328         if (err == -EINPROGRESS)
 329                 return;
 330
 331         if (!err)
 332                 memcpy(priv->result, req->result,
 333                        crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
 334
 335         kzfree(priv);
 336 }
 337
 338 static void ahash_def_finup_done2(struct crypto_async_request *req, int err)
 339 {
 340         struct ahash_request *areq = req->data;
 341         struct ahash_request_priv *priv = areq->priv;
 342         crypto_completion_t complete = priv->complete;
 343         void *data = priv->data;
 344
 345         ahash_def_finup_finish2(areq, err);
 346
 347         complete(data, err);
 348 }
 349
 350 static int ahash_def_finup_finish1(struct ahash_request *req, int err)
 351 {
 352         if (err)
 353                 goto out;
 354
 355         req->base.complete = ahash_def_finup_done2;
 356         req->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
 357         err = crypto_ahash_reqtfm(req)->final(req);
 358
 359 out:
 360         ahash_def_finup_finish2(req, err);
 361         return err;
 362 }
 363
 364 static void ahash_def_finup_done1(struct crypto_async_request *req, int err)
 365 {
 366         struct ahash_request *areq = req->data;
 367         struct ahash_request_priv *priv = areq->priv;
 368         crypto_completion_t complete = priv->complete;
 369         void *data = priv->data;
 370
 371         err = ahash_def_finup_finish1(areq, err);
 372
 373         complete(data, err);
 374 }
 375
 376 static int ahash_def_finup(struct ahash_request *req)
 377 {
 378         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 379         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 380         unsigned int ds = crypto_ahash_digestsize(tfm);
 381         struct ahash_request_priv *priv;
 382
 383         priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
 384                        (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
 385                        GFP_KERNEL : GFP_ATOMIC);
 386         if (!priv)
 387                 return -ENOMEM;
 388
 389         priv->result = req->result;
 390         priv->complete = req->base.complete;
 391         priv->data = req->base.data;
 392
 393         req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
 394         req->base.complete = ahash_def_finup_done1;
 395         req->base.data = req;
 396         req->priv = priv;
 397
 398         return ahash_def_finup_finish1(req, tfm->update(req));
 399 }
 400
 401 static int ahash_no_export(struct ahash_request *req, void *out)
 402 {
 403         return -ENOSYS;
 404 }
 405
 406 static int ahash_no_import(struct ahash_request *req, const void *in)
 407 {
 408         return -ENOSYS;
 409 }
 410
 411 static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
 412 {
 413         struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
 414         struct ahash_alg *alg = crypto_ahash_alg(hash);
 415
 416         hash->setkey = ahash_nosetkey;
 417         hash->export = ahash_no_export;
 418         hash->import = ahash_no_import;
 419
 420         if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
 421                 return crypto_init_shash_ops_async(tfm);
 422
 423         hash->init = alg->init;
 424         hash->update = alg->update;
 425         hash->final = alg->final;
 426         hash->finup = alg->finup ?: ahash_def_finup;
 427         hash->digest = alg->digest;
 428
 429         if (alg->setkey)
 430                 hash->setkey = alg->setkey;
 431         if (alg->export)
 432                 hash->export = alg->export;
 433         if (alg->import)
 434                 hash->import = alg->import;
 435
 436         return 0;
 437 }
 438
 439 static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
 440 {
 441         if (alg->cra_type == &crypto_ahash_type)
 442                 return alg->cra_ctxsize;
 443
 444         return sizeof(struct crypto_shash *);
 445 }
 446
 447 #ifdef CONFIG_NET
 448 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 449 {
 450         struct crypto_report_hash rhash;
 451
 452         strncpy(rhash.type, "ahash", sizeof(rhash.type));
 453
 454         rhash.blocksize = alg->cra_blocksize;
 455         rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
 456
 457         if (nla_put(skb, CRYPTOCFGA_REPORT_HASH,
 458                     sizeof(struct crypto_report_hash), &rhash))
 459                 goto nla_put_failure;
 460         return 0;
 461
 462 nla_put_failure:
 463         return -EMSGSIZE;
 464 }
 465 #else
 466 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 467 {
 468         return -ENOSYS;
 469 }
 470 #endif
 471
 472 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 473         __attribute__ ((unused));
 474 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 475 {
 476         seq_printf(m, "type         : ahash\n");
 477         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 478                                              "yes" : "no");
 479         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 480         seq_printf(m, "digestsize   : %u\n",
 481                    __crypto_hash_alg_common(alg)->digestsize);
 482 }
 483
 484 const struct crypto_type crypto_ahash_type = {
 485         .extsize = crypto_ahash_extsize,
 486         .init_tfm = crypto_ahash_init_tfm,
 487 #ifdef CONFIG_PROC_FS
 488         .show = crypto_ahash_show,
 489 #endif
 490         .report = crypto_ahash_report,
 491         .maskclear = ~CRYPTO_ALG_TYPE_MASK,
 492         .maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
 493         .type = CRYPTO_ALG_TYPE_AHASH,
 494         .tfmsize = offsetof(struct crypto_ahash, base),
 495 };
 496 EXPORT_SYMBOL_GPL(crypto_ahash_type);
 497
 498 struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
 499                                         u32 mask)
 500 {
 501         return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
 502 }
 503 EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
 504
 505 static int ahash_prepare_alg(struct ahash_alg *alg)
 506 {
 507         struct crypto_alg *base = &alg->halg.base;
 508
 509         if (alg->halg.digestsize > PAGE_SIZE / 8 ||
 510             alg->halg.statesize > PAGE_SIZE / 8)
 511                 return -EINVAL;
 512
 513         base->cra_type = &crypto_ahash_type;
 514         base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
 515         base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
 516
 517         return 0;
 518 }
 519
 520 int crypto_register_ahash(struct ahash_alg *alg)
 521 {
 522         struct crypto_alg *base = &alg->halg.base;
 523         int err;
 524
 525         err = ahash_prepare_alg(alg);
 526         if (err)
 527                 return err;
 528
 529         return crypto_register_alg(base);
 530 }
 531 EXPORT_SYMBOL_GPL(crypto_register_ahash);
 532
 533 int crypto_unregister_ahash(struct ahash_alg *alg)
 534 {
 535         return crypto_unregister_alg(&alg->halg.base);
 536 }
 537 EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
 538
 539 int ahash_register_instance(struct crypto_template *tmpl,
 540                             struct ahash_instance *inst)
 541 {
 542         int err;
 543
 544         err = ahash_prepare_alg(&inst->alg);
 545         if (err)
 546                 return err;
 547
 548         return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
 549 }
 550 EXPORT_SYMBOL_GPL(ahash_register_instance);
 551
 552 void ahash_free_instance(struct crypto_instance *inst)
 553 {
 554         crypto_drop_spawn(crypto_instance_ctx(inst));
 555         kfree(ahash_instance(inst));
 556 }
 557 EXPORT_SYMBOL_GPL(ahash_free_instance);
 558
 559 int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
 560                             struct hash_alg_common *alg,
 561                             struct crypto_instance *inst)
 562 {
 563         return crypto_init_spawn2(&spawn->base, &alg->base, inst,
 564                                   &crypto_ahash_type);
 565 }
 566 EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn);
 567
 568 struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
 569 {
 570         struct crypto_alg *alg;
 571
 572         alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask);
 573         return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg);
 574 }
 575 EXPORT_SYMBOL_GPL(ahash_attr_alg);
 576
 577 MODULE_LICENSE("GPL");
 578 MODULE_DESCRIPTION("Asynchronous cryptographic hash type");