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 = crypto_kmap(walk->pg, 0);
  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->offset = sg->offset;
  68         walk->pg = sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
  69         walk->offset = offset_in_page(walk->offset);
  70         walk->entrylen = sg->length;
  71
  72         if (walk->entrylen > walk->total)
  73                 walk->entrylen = walk->total;
  74         walk->total -= walk->entrylen;
  75
  76         return hash_walk_next(walk);
  77 }
  78
  79 int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
  80 {
  81         unsigned int alignmask = walk->alignmask;
  82         unsigned int nbytes = walk->entrylen;
  83
  84         walk->data -= walk->offset;
  85
  86         if (nbytes && walk->offset & alignmask && !err) {
  87                 walk->offset = ALIGN(walk->offset, alignmask + 1);
  88                 walk->data += walk->offset;
  89
  90                 nbytes = min(nbytes,
  91                              ((unsigned int)(PAGE_SIZE)) - walk->offset);
  92                 walk->entrylen -= nbytes;
  93
  94                 return nbytes;
  95         }
  96
  97         crypto_kunmap(walk->data, 0);
  98         crypto_yield(walk->flags);
  99
 100         if (err)
 101                 return err;
 102
 103         if (nbytes) {
 104                 walk->offset = 0;
 105                 walk->pg++;
 106                 return hash_walk_next(walk);
 107         }
 108
 109         if (!walk->total)
 110                 return 0;
 111
 112         walk->sg = scatterwalk_sg_next(walk->sg);
 113
 114         return hash_walk_new_entry(walk);
 115 }
 116 EXPORT_SYMBOL_GPL(crypto_hash_walk_done);
 117
 118 int crypto_hash_walk_first(struct ahash_request *req,
 119                            struct crypto_hash_walk *walk)
 120 {
 121         walk->total = req->nbytes;
 122
 123         if (!walk->total)
 124                 return 0;
 125
 126         walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
 127         walk->sg = req->src;
 128         walk->flags = req->base.flags;
 129
 130         return hash_walk_new_entry(walk);
 131 }
 132 EXPORT_SYMBOL_GPL(crypto_hash_walk_first);
 133
 134 int crypto_hash_walk_first_compat(struct hash_desc *hdesc,
 135                                   struct crypto_hash_walk *walk,
 136                                   struct scatterlist *sg, unsigned int len)
 137 {
 138         walk->total = len;
 139
 140         if (!walk->total)
 141                 return 0;
 142
 143         walk->alignmask = crypto_hash_alignmask(hdesc->tfm);
 144         walk->sg = sg;
 145         walk->flags = hdesc->flags;
 146
 147         return hash_walk_new_entry(walk);
 148 }
 149
 150 static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,
 151                                 unsigned int keylen)
 152 {
 153         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 154         int ret;
 155         u8 *buffer, *alignbuffer;
 156         unsigned long absize;
 157
 158         absize = keylen + alignmask;
 159         buffer = kmalloc(absize, GFP_KERNEL);
 160         if (!buffer)
 161                 return -ENOMEM;
 162
 163         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 164         memcpy(alignbuffer, key, keylen);
 165         ret = tfm->setkey(tfm, alignbuffer, keylen);
 166         kzfree(buffer);
 167         return ret;
 168 }
 169
 170 int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
 171                         unsigned int keylen)
 172 {
 173         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 174
 175         if ((unsigned long)key & alignmask)
 176                 return ahash_setkey_unaligned(tfm, key, keylen);
 177
 178         return tfm->setkey(tfm, key, keylen);
 179 }
 180 EXPORT_SYMBOL_GPL(crypto_ahash_setkey);
 181
 182 static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
 183                           unsigned int keylen)
 184 {
 185         return -ENOSYS;
 186 }
 187
 188 static inline unsigned int ahash_align_buffer_size(unsigned len,
 189                                                    unsigned long mask)
 190 {
 191         return len + (mask & ~(crypto_tfm_ctx_alignment() - 1));
 192 }
 193
 194 static void ahash_op_unaligned_finish(struct ahash_request *req, int err)
 195 {
 196         struct ahash_request_priv *priv = req->priv;
 197
 198         if (err == -EINPROGRESS)
 199                 return;
 200
 201         if (!err)
 202                 memcpy(priv->result, req->result,
 203                        crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
 204
 205         /* Restore the original crypto request. */
 206         req->result = priv->result;
 207         req->base.complete = priv->complete;
 208         req->base.data = priv->data;
 209         req->priv = NULL;
 210
 211         /* Free the req->priv.priv from the ADJUSTED request. */
 212         kzfree(priv);
 213 }
 214
 215 static void ahash_op_unaligned_done(struct crypto_async_request *req, int err)
 216 {
 217         struct ahash_request *areq = req->data;
 218
 219         /*
 220          * Restore the original request, see ahash_op_unaligned() for what
 221          * goes where.
 222          *
 223          * The "struct ahash_request *req" here is in fact the "req.base"
 224          * from the ADJUSTED request from ahash_op_unaligned(), thus as it
 225          * is a pointer to self, it is also the ADJUSTED "req" .
 226          */
 227
 228         /* First copy areq->result into areq->priv.result */
 229         ahash_op_unaligned_finish(areq, err);
 230
 231         /* Complete the ORIGINAL request. */
 232         areq->base.complete(&areq->base, err);
 233 }
 234
 235 static int ahash_op_unaligned(struct ahash_request *req,
 236                               int (*op)(struct ahash_request *))
 237 {
 238         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 239         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 240         unsigned int ds = crypto_ahash_digestsize(tfm);
 241         struct ahash_request_priv *priv;
 242         int err;
 243
 244         priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
 245                        (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
 246                        GFP_KERNEL : GFP_ATOMIC);
 247         if (!priv)
 248                 return -ENOMEM;
 249
 250         /*
 251          * WARNING: Voodoo programming below!
 252          *
 253          * The code below is obscure and hard to understand, thus explanation
 254          * is necessary. See include/crypto/hash.h and include/linux/crypto.h
 255          * to understand the layout of structures used here!
 256          *
 257          * The code here will replace portions of the ORIGINAL request with
 258          * pointers to new code and buffers so the hashing operation can store
 259          * the result in aligned buffer. We will call the modified request
 260          * an ADJUSTED request.
 261          *
 262          * The newly mangled request will look as such:
 263          *
 264          * req {
 265          *   .result        = ADJUSTED[new aligned buffer]
 266          *   .base.complete = ADJUSTED[pointer to completion function]
 267          *   .base.data     = ADJUSTED[*req (pointer to self)]
 268          *   .priv          = ADJUSTED[new priv] {
 269          *           .result   = ORIGINAL(result)
 270          *           .complete = ORIGINAL(base.complete)
 271          *           .data     = ORIGINAL(base.data)
 272          *   }
 273          */
 274
 275         priv->result = req->result;
 276         priv->complete = req->base.complete;
 277         priv->data = req->base.data;
 278         /*
 279          * WARNING: We do not backup req->priv here! The req->priv
 280          *          is for internal use of the Crypto API and the
 281          *          user must _NOT_ _EVER_ depend on it's content!
 282          */
 283
 284         req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
 285         req->base.complete = ahash_op_unaligned_done;
 286         req->base.data = req;
 287         req->priv = priv;
 288
 289         err = op(req);
 290         ahash_op_unaligned_finish(req, err);
 291
 292         return err;
 293 }
 294
 295 static int crypto_ahash_op(struct ahash_request *req,
 296                            int (*op)(struct ahash_request *))
 297 {
 298         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 299         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 300
 301         if ((unsigned long)req->result & alignmask)
 302                 return ahash_op_unaligned(req, op);
 303
 304         return op(req);
 305 }
 306
 307 int crypto_ahash_final(struct ahash_request *req)
 308 {
 309         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
 310 }
 311 EXPORT_SYMBOL_GPL(crypto_ahash_final);
 312
 313 int crypto_ahash_finup(struct ahash_request *req)
 314 {
 315         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
 316 }
 317 EXPORT_SYMBOL_GPL(crypto_ahash_finup);
 318
 319 int crypto_ahash_digest(struct ahash_request *req)
 320 {
 321         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->digest);
 322 }
 323 EXPORT_SYMBOL_GPL(crypto_ahash_digest);
 324
 325 static void ahash_def_finup_finish2(struct ahash_request *req, int err)
 326 {
 327         struct ahash_request_priv *priv = req->priv;
 328
 329         if (err == -EINPROGRESS)
 330                 return;
 331
 332         if (!err)
 333                 memcpy(priv->result, req->result,
 334                        crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
 335
 336         kzfree(priv);
 337 }
 338
 339 static void ahash_def_finup_done2(struct crypto_async_request *req, int err)
 340 {
 341         struct ahash_request *areq = req->data;
 342         struct ahash_request_priv *priv = areq->priv;
 343         crypto_completion_t complete = priv->complete;
 344         void *data = priv->data;
 345
 346         ahash_def_finup_finish2(areq, err);
 347
 348         complete(data, err);
 349 }
 350
 351 static int ahash_def_finup_finish1(struct ahash_request *req, int err)
 352 {
 353         if (err)
 354                 goto out;
 355
 356         req->base.complete = ahash_def_finup_done2;
 357         req->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
 358         err = crypto_ahash_reqtfm(req)->final(req);
 359
 360 out:
 361         ahash_def_finup_finish2(req, err);
 362         return err;
 363 }
 364
 365 static void ahash_def_finup_done1(struct crypto_async_request *req, int err)
 366 {
 367         struct ahash_request *areq = req->data;
 368         struct ahash_request_priv *priv = areq->priv;
 369         crypto_completion_t complete = priv->complete;
 370         void *data = priv->data;
 371
 372         err = ahash_def_finup_finish1(areq, err);
 373
 374         complete(data, err);
 375 }
 376
 377 static int ahash_def_finup(struct ahash_request *req)
 378 {
 379         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 380         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 381         unsigned int ds = crypto_ahash_digestsize(tfm);
 382         struct ahash_request_priv *priv;
 383
 384         priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
 385                        (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
 386                        GFP_KERNEL : GFP_ATOMIC);
 387         if (!priv)
 388                 return -ENOMEM;
 389
 390         priv->result = req->result;
 391         priv->complete = req->base.complete;
 392         priv->data = req->base.data;
 393
 394         req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
 395         req->base.complete = ahash_def_finup_done1;
 396         req->base.data = req;
 397         req->priv = priv;
 398
 399         return ahash_def_finup_finish1(req, tfm->update(req));
 400 }
 401
 402 static int ahash_no_export(struct ahash_request *req, void *out)
 403 {
 404         return -ENOSYS;
 405 }
 406
 407 static int ahash_no_import(struct ahash_request *req, const void *in)
 408 {
 409         return -ENOSYS;
 410 }
 411
 412 static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
 413 {
 414         struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
 415         struct ahash_alg *alg = crypto_ahash_alg(hash);
 416
 417         hash->setkey = ahash_nosetkey;
 418         hash->has_setkey = false;
 419         hash->export = ahash_no_export;
 420         hash->import = ahash_no_import;
 421
 422         if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
 423                 return crypto_init_shash_ops_async(tfm);
 424
 425         hash->init = alg->init;
 426         hash->update = alg->update;
 427         hash->final = alg->final;
 428         hash->finup = alg->finup ?: ahash_def_finup;
 429         hash->digest = alg->digest;
 430
 431         if (alg->setkey) {
 432                 hash->setkey = alg->setkey;
 433                 hash->has_setkey = true;
 434         }
 435         if (alg->export)
 436                 hash->export = alg->export;
 437         if (alg->import)
 438                 hash->import = alg->import;
 439
 440         return 0;
 441 }
 442
 443 static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
 444 {
 445         if (alg->cra_type == &crypto_ahash_type)
 446                 return alg->cra_ctxsize;
 447
 448         return sizeof(struct crypto_shash *);
 449 }
 450
 451 #ifdef CONFIG_NET
 452 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 453 {
 454         struct crypto_report_hash rhash;
 455
 456         strncpy(rhash.type, "ahash", sizeof(rhash.type));
 457
 458         rhash.blocksize = alg->cra_blocksize;
 459         rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
 460
 461         NLA_PUT(skb, CRYPTOCFGA_REPORT_HASH,
 462                 sizeof(struct crypto_report_hash), &rhash);
 463
 464         return 0;
 465
 466 nla_put_failure:
 467         return -EMSGSIZE;
 468 }
 469 #else
 470 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 471 {
 472         return -ENOSYS;
 473 }
 474 #endif
 475
 476 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 477         __attribute__ ((unused));
 478 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 479 {
 480         seq_printf(m, "type         : ahash\n");
 481         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 482                                              "yes" : "no");
 483         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 484         seq_printf(m, "digestsize   : %u\n",
 485                    __crypto_hash_alg_common(alg)->digestsize);
 486 }
 487
 488 const struct crypto_type crypto_ahash_type = {
 489         .extsize = crypto_ahash_extsize,
 490         .init_tfm = crypto_ahash_init_tfm,
 491 #ifdef CONFIG_PROC_FS
 492         .show = crypto_ahash_show,
 493 #endif
 494         .report = crypto_ahash_report,
 495         .maskclear = ~CRYPTO_ALG_TYPE_MASK,
 496         .maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
 497         .type = CRYPTO_ALG_TYPE_AHASH,
 498         .tfmsize = offsetof(struct crypto_ahash, base),
 499 };
 500 EXPORT_SYMBOL_GPL(crypto_ahash_type);
 501
 502 struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
 503                                         u32 mask)
 504 {
 505         return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
 506 }
 507 EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
 508
 509 static int ahash_prepare_alg(struct ahash_alg *alg)
 510 {
 511         struct crypto_alg *base = &alg->halg.base;
 512
 513         if (alg->halg.digestsize > PAGE_SIZE / 8 ||
 514             alg->halg.statesize > PAGE_SIZE / 8 ||
 515             alg->halg.statesize == 0)
 516                 return -EINVAL;
 517
 518         base->cra_type = &crypto_ahash_type;
 519         base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
 520         base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
 521
 522         return 0;
 523 }
 524
 525 int crypto_register_ahash(struct ahash_alg *alg)
 526 {
 527         struct crypto_alg *base = &alg->halg.base;
 528         int err;
 529
 530         err = ahash_prepare_alg(alg);
 531         if (err)
 532                 return err;
 533
 534         return crypto_register_alg(base);
 535 }
 536 EXPORT_SYMBOL_GPL(crypto_register_ahash);
 537
 538 int crypto_unregister_ahash(struct ahash_alg *alg)
 539 {
 540         return crypto_unregister_alg(&alg->halg.base);
 541 }
 542 EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
 543
 544 int ahash_register_instance(struct crypto_template *tmpl,
 545                             struct ahash_instance *inst)
 546 {
 547         int err;
 548
 549         err = ahash_prepare_alg(&inst->alg);
 550         if (err)
 551                 return err;
 552
 553         return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
 554 }
 555 EXPORT_SYMBOL_GPL(ahash_register_instance);
 556
 557 void ahash_free_instance(struct crypto_instance *inst)
 558 {
 559         crypto_drop_spawn(crypto_instance_ctx(inst));
 560         kfree(ahash_instance(inst));
 561 }
 562 EXPORT_SYMBOL_GPL(ahash_free_instance);
 563
 564 int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
 565                             struct hash_alg_common *alg,
 566                             struct crypto_instance *inst)
 567 {
 568         return crypto_init_spawn2(&spawn->base, &alg->base, inst,
 569                                   &crypto_ahash_type);
 570 }
 571 EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn);
 572
 573 struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
 574 {
 575         struct crypto_alg *alg;
 576
 577         alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask);
 578         return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg);
 579 }
 580 EXPORT_SYMBOL_GPL(ahash_attr_alg);
 581
 582 MODULE_LICENSE("GPL");
 583 MODULE_DESCRIPTION("Asynchronous cryptographic hash type");