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 int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt)
 195 {
 196         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 197         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 198         unsigned int ds = crypto_ahash_digestsize(tfm);
 199         struct ahash_request_priv *priv;
 200
 201         priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
 202                        (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
 203                        GFP_KERNEL : GFP_ATOMIC);
 204         if (!priv)
 205                 return -ENOMEM;
 206
 207         /*
 208          * WARNING: Voodoo programming below!
 209          *
 210          * The code below is obscure and hard to understand, thus explanation
 211          * is necessary. See include/crypto/hash.h and include/linux/crypto.h
 212          * to understand the layout of structures used here!
 213          *
 214          * The code here will replace portions of the ORIGINAL request with
 215          * pointers to new code and buffers so the hashing operation can store
 216          * the result in aligned buffer. We will call the modified request
 217          * an ADJUSTED request.
 218          *
 219          * The newly mangled request will look as such:
 220          *
 221          * req {
 222          *   .result        = ADJUSTED[new aligned buffer]
 223          *   .base.complete = ADJUSTED[pointer to completion function]
 224          *   .base.data     = ADJUSTED[*req (pointer to self)]
 225          *   .priv          = ADJUSTED[new priv] {
 226          *           .result   = ORIGINAL(result)
 227          *           .complete = ORIGINAL(base.complete)
 228          *           .data     = ORIGINAL(base.data)
 229          *   }
 230          */
 231
 232         priv->result = req->result;
 233         priv->complete = req->base.complete;
 234         priv->data = req->base.data;
 235         /*
 236          * WARNING: We do not backup req->priv here! The req->priv
 237          *          is for internal use of the Crypto API and the
 238          *          user must _NOT_ _EVER_ depend on it's content!
 239          */
 240
 241         req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
 242         req->base.complete = cplt;
 243         req->base.data = req;
 244         req->priv = priv;
 245
 246         return 0;
 247 }
 248
 249 static void ahash_restore_req(struct ahash_request *req)
 250 {
 251         struct ahash_request_priv *priv = req->priv;
 252
 253         /* Restore the original crypto request. */
 254         req->result = priv->result;
 255         req->base.complete = priv->complete;
 256         req->base.data = priv->data;
 257         req->priv = NULL;
 258
 259         /* Free the req->priv.priv from the ADJUSTED request. */
 260         kzfree(priv);
 261 }
 262
 263 static void ahash_op_unaligned_finish(struct ahash_request *req, int err)
 264 {
 265         struct ahash_request_priv *priv = req->priv;
 266
 267         if (err == -EINPROGRESS)
 268                 return;
 269
 270         if (!err)
 271                 memcpy(priv->result, req->result,
 272                        crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
 273
 274         ahash_restore_req(req);
 275 }
 276
 277 static void ahash_op_unaligned_done(struct crypto_async_request *req, int err)
 278 {
 279         struct ahash_request *areq = req->data;
 280
 281         /*
 282          * Restore the original request, see ahash_op_unaligned() for what
 283          * goes where.
 284          *
 285          * The "struct ahash_request *req" here is in fact the "req.base"
 286          * from the ADJUSTED request from ahash_op_unaligned(), thus as it
 287          * is a pointer to self, it is also the ADJUSTED "req" .
 288          */
 289
 290         /* First copy req->result into req->priv.result */
 291         ahash_op_unaligned_finish(areq, err);
 292
 293         /* Complete the ORIGINAL request. */
 294         areq->base.complete(&areq->base, err);
 295 }
 296
 297 static int ahash_op_unaligned(struct ahash_request *req,
 298                               int (*op)(struct ahash_request *))
 299 {
 300         int err;
 301
 302         err = ahash_save_req(req, ahash_op_unaligned_done);
 303         if (err)
 304                 return err;
 305
 306         err = op(req);
 307         ahash_op_unaligned_finish(req, err);
 308
 309         return err;
 310 }
 311
 312 static int crypto_ahash_op(struct ahash_request *req,
 313                            int (*op)(struct ahash_request *))
 314 {
 315         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 316         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 317
 318         if ((unsigned long)req->result & alignmask)
 319                 return ahash_op_unaligned(req, op);
 320
 321         return op(req);
 322 }
 323
 324 int crypto_ahash_final(struct ahash_request *req)
 325 {
 326         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
 327 }
 328 EXPORT_SYMBOL_GPL(crypto_ahash_final);
 329
 330 int crypto_ahash_finup(struct ahash_request *req)
 331 {
 332         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
 333 }
 334 EXPORT_SYMBOL_GPL(crypto_ahash_finup);
 335
 336 int crypto_ahash_digest(struct ahash_request *req)
 337 {
 338         return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->digest);
 339 }
 340 EXPORT_SYMBOL_GPL(crypto_ahash_digest);
 341
 342 static void ahash_def_finup_finish2(struct ahash_request *req, int err)
 343 {
 344         struct ahash_request_priv *priv = req->priv;
 345
 346         if (err == -EINPROGRESS)
 347                 return;
 348
 349         if (!err)
 350                 memcpy(priv->result, req->result,
 351                        crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
 352
 353         kzfree(priv);
 354 }
 355
 356 static void ahash_def_finup_done2(struct crypto_async_request *req, int err)
 357 {
 358         struct ahash_request *areq = req->data;
 359         struct ahash_request_priv *priv = areq->priv;
 360         crypto_completion_t complete = priv->complete;
 361         void *data = priv->data;
 362
 363         ahash_def_finup_finish2(areq, err);
 364
 365         complete(data, 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         req->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
 375         err = crypto_ahash_reqtfm(req)->final(req);
 376
 377 out:
 378         ahash_def_finup_finish2(req, err);
 379         return err;
 380 }
 381
 382 static void ahash_def_finup_done1(struct crypto_async_request *req, int err)
 383 {
 384         struct ahash_request *areq = req->data;
 385         struct ahash_request_priv *priv = areq->priv;
 386         crypto_completion_t complete = priv->complete;
 387         void *data = priv->data;
 388
 389         err = ahash_def_finup_finish1(areq, err);
 390
 391         complete(data, err);
 392 }
 393
 394 static int ahash_def_finup(struct ahash_request *req)
 395 {
 396         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 397         unsigned long alignmask = crypto_ahash_alignmask(tfm);
 398         unsigned int ds = crypto_ahash_digestsize(tfm);
 399         struct ahash_request_priv *priv;
 400
 401         priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
 402                        (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
 403                        GFP_KERNEL : GFP_ATOMIC);
 404         if (!priv)
 405                 return -ENOMEM;
 406
 407         priv->result = req->result;
 408         priv->complete = req->base.complete;
 409         priv->data = req->base.data;
 410
 411         req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
 412         req->base.complete = ahash_def_finup_done1;
 413         req->base.data = req;
 414         req->priv = priv;
 415
 416         return ahash_def_finup_finish1(req, tfm->update(req));
 417 }
 418
 419 static int ahash_no_export(struct ahash_request *req, void *out)
 420 {
 421         return -ENOSYS;
 422 }
 423
 424 static int ahash_no_import(struct ahash_request *req, const void *in)
 425 {
 426         return -ENOSYS;
 427 }
 428
 429 static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
 430 {
 431         struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
 432         struct ahash_alg *alg = crypto_ahash_alg(hash);
 433
 434         hash->setkey = ahash_nosetkey;
 435         hash->has_setkey = false;
 436         hash->export = ahash_no_export;
 437         hash->import = ahash_no_import;
 438
 439         if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
 440                 return crypto_init_shash_ops_async(tfm);
 441
 442         hash->init = alg->init;
 443         hash->update = alg->update;
 444         hash->final = alg->final;
 445         hash->finup = alg->finup ?: ahash_def_finup;
 446         hash->digest = alg->digest;
 447
 448         if (alg->setkey) {
 449                 hash->setkey = alg->setkey;
 450                 hash->has_setkey = true;
 451         }
 452         if (alg->export)
 453                 hash->export = alg->export;
 454         if (alg->import)
 455                 hash->import = alg->import;
 456
 457         return 0;
 458 }
 459
 460 static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
 461 {
 462         if (alg->cra_type == &crypto_ahash_type)
 463                 return alg->cra_ctxsize;
 464
 465         return sizeof(struct crypto_shash *);
 466 }
 467
 468 #ifdef CONFIG_NET
 469 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 470 {
 471         struct crypto_report_hash rhash;
 472
 473         strncpy(rhash.type, "ahash", sizeof(rhash.type));
 474
 475         rhash.blocksize = alg->cra_blocksize;
 476         rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
 477
 478         NLA_PUT(skb, CRYPTOCFGA_REPORT_HASH,
 479                 sizeof(struct crypto_report_hash), &rhash);
 480
 481         return 0;
 482
 483 nla_put_failure:
 484         return -EMSGSIZE;
 485 }
 486 #else
 487 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 488 {
 489         return -ENOSYS;
 490 }
 491 #endif
 492
 493 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 494         __attribute__ ((unused));
 495 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 496 {
 497         seq_printf(m, "type         : ahash\n");
 498         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 499                                              "yes" : "no");
 500         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 501         seq_printf(m, "digestsize   : %u\n",
 502                    __crypto_hash_alg_common(alg)->digestsize);
 503 }
 504
 505 const struct crypto_type crypto_ahash_type = {
 506         .extsize = crypto_ahash_extsize,
 507         .init_tfm = crypto_ahash_init_tfm,
 508 #ifdef CONFIG_PROC_FS
 509         .show = crypto_ahash_show,
 510 #endif
 511         .report = crypto_ahash_report,
 512         .maskclear = ~CRYPTO_ALG_TYPE_MASK,
 513         .maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
 514         .type = CRYPTO_ALG_TYPE_AHASH,
 515         .tfmsize = offsetof(struct crypto_ahash, base),
 516 };
 517 EXPORT_SYMBOL_GPL(crypto_ahash_type);
 518
 519 struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
 520                                         u32 mask)
 521 {
 522         return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
 523 }
 524 EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
 525
 526 static int ahash_prepare_alg(struct ahash_alg *alg)
 527 {
 528         struct crypto_alg *base = &alg->halg.base;
 529
 530         if (alg->halg.digestsize > PAGE_SIZE / 8 ||
 531             alg->halg.statesize > PAGE_SIZE / 8 ||
 532             alg->halg.statesize == 0)
 533                 return -EINVAL;
 534
 535         base->cra_type = &crypto_ahash_type;
 536         base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
 537         base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
 538
 539         return 0;
 540 }
 541
 542 int crypto_register_ahash(struct ahash_alg *alg)
 543 {
 544         struct crypto_alg *base = &alg->halg.base;
 545         int err;
 546
 547         err = ahash_prepare_alg(alg);
 548         if (err)
 549                 return err;
 550
 551         return crypto_register_alg(base);
 552 }
 553 EXPORT_SYMBOL_GPL(crypto_register_ahash);
 554
 555 int crypto_unregister_ahash(struct ahash_alg *alg)
 556 {
 557         return crypto_unregister_alg(&alg->halg.base);
 558 }
 559 EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
 560
 561 int ahash_register_instance(struct crypto_template *tmpl,
 562                             struct ahash_instance *inst)
 563 {
 564         int err;
 565
 566         err = ahash_prepare_alg(&inst->alg);
 567         if (err)
 568                 return err;
 569
 570         return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
 571 }
 572 EXPORT_SYMBOL_GPL(ahash_register_instance);
 573
 574 void ahash_free_instance(struct crypto_instance *inst)
 575 {
 576         crypto_drop_spawn(crypto_instance_ctx(inst));
 577         kfree(ahash_instance(inst));
 578 }
 579 EXPORT_SYMBOL_GPL(ahash_free_instance);
 580
 581 int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
 582                             struct hash_alg_common *alg,
 583                             struct crypto_instance *inst)
 584 {
 585         return crypto_init_spawn2(&spawn->base, &alg->base, inst,
 586                                   &crypto_ahash_type);
 587 }
 588 EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn);
 589
 590 struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
 591 {
 592         struct crypto_alg *alg;
 593
 594         alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask);
 595         return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg);
 596 }
 597 EXPORT_SYMBOL_GPL(ahash_attr_alg);
 598
 599 MODULE_LICENSE("GPL");
 600 MODULE_DESCRIPTION("Asynchronous cryptographic hash type");