linux/crypto/ahash.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Asynchronous Cryptographic Hash operations.
   4 *
   5 * This is the asynchronous version of hash.c with notification of
   6 * completion via a callback.
   7 *
   8 * Copyright (c) 2008 Loc Ho <lho@amcc.com>
   9 */
  10
  11#include <crypto/internal/hash.h>
  12#include <crypto/scatterwalk.h>
  13#include <linux/err.h>
  14#include <linux/kernel.h>
  15#include <linux/module.h>
  16#include <linux/sched.h>
  17#include <linux/slab.h>
  18#include <linux/seq_file.h>
  19#include <linux/cryptouser.h>
  20#include <linux/compiler.h>
  21#include <net/netlink.h>
  22
  23#include "internal.h"
  24
  25static const struct crypto_type crypto_ahash_type;
  26
  27struct ahash_request_priv {
  28        crypto_completion_t complete;
  29        void *data;
  30        u8 *result;
  31        u32 flags;
  32        void *ubuf[] CRYPTO_MINALIGN_ATTR;
  33};
  34
  35static inline struct ahash_alg *crypto_ahash_alg(struct crypto_ahash *hash)
  36{
  37        return container_of(crypto_hash_alg_common(hash), struct ahash_alg,
  38                            halg);
  39}
  40
  41static int hash_walk_next(struct crypto_hash_walk *walk)
  42{
  43        unsigned int alignmask = walk->alignmask;
  44        unsigned int offset = walk->offset;
  45        unsigned int nbytes = min(walk->entrylen,
  46                                  ((unsigned int)(PAGE_SIZE)) - offset);
  47
  48        walk->data = kmap_atomic(walk->pg);
  49        walk->data += offset;
  50
  51        if (offset & alignmask) {
  52                unsigned int unaligned = alignmask + 1 - (offset & alignmask);
  53
  54                if (nbytes > unaligned)
  55                        nbytes = unaligned;
  56        }
  57
  58        walk->entrylen -= nbytes;
  59        return nbytes;
  60}
  61
  62static 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
  79int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
  80{
  81        unsigned int alignmask = walk->alignmask;
  82
  83        walk->data -= walk->offset;
  84
  85        if (walk->entrylen && (walk->offset & alignmask) && !err) {
  86                unsigned int nbytes;
  87
  88                walk->offset = ALIGN(walk->offset, alignmask + 1);
  89                nbytes = min(walk->entrylen,
  90                             (unsigned int)(PAGE_SIZE - walk->offset));
  91                if (nbytes) {
  92                        walk->entrylen -= nbytes;
  93                        walk->data += walk->offset;
  94                        return nbytes;
  95                }
  96        }
  97
  98        kunmap_atomic(walk->data);
  99        crypto_yield(walk->flags);
 100
 101        if (err)
 102                return err;
 103
 104        if (walk->entrylen) {
 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 = sg_next(walk->sg);
 114
 115        return hash_walk_new_entry(walk);
 116}
 117EXPORT_SYMBOL_GPL(crypto_hash_walk_done);
 118
 119int 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                walk->entrylen = 0;
 126                return 0;
 127        }
 128
 129        walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
 130        walk->sg = req->src;
 131        walk->flags = req->base.flags;
 132
 133        return hash_walk_new_entry(walk);
 134}
 135EXPORT_SYMBOL_GPL(crypto_hash_walk_first);
 136
 137static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,
 138                                unsigned int keylen)
 139{
 140        unsigned long alignmask = crypto_ahash_alignmask(tfm);
 141        int ret;
 142        u8 *buffer, *alignbuffer;
 143        unsigned long absize;
 144
 145        absize = keylen + alignmask;
 146        buffer = kmalloc(absize, GFP_KERNEL);
 147        if (!buffer)
 148                return -ENOMEM;
 149
 150        alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 151        memcpy(alignbuffer, key, keylen);
 152        ret = tfm->setkey(tfm, alignbuffer, keylen);
 153        kfree_sensitive(buffer);
 154        return ret;
 155}
 156
 157static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
 158                          unsigned int keylen)
 159{
 160        return -ENOSYS;
 161}
 162
 163static void ahash_set_needkey(struct crypto_ahash *tfm)
 164{
 165        const struct hash_alg_common *alg = crypto_hash_alg_common(tfm);
 166
 167        if (tfm->setkey != ahash_nosetkey &&
 168            !(alg->base.cra_flags & CRYPTO_ALG_OPTIONAL_KEY))
 169                crypto_ahash_set_flags(tfm, CRYPTO_TFM_NEED_KEY);
 170}
 171
 172int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
 173                        unsigned int keylen)
 174{
 175        unsigned long alignmask = crypto_ahash_alignmask(tfm);
 176        int err;
 177
 178        if ((unsigned long)key & alignmask)
 179                err = ahash_setkey_unaligned(tfm, key, keylen);
 180        else
 181                err = tfm->setkey(tfm, key, keylen);
 182
 183        if (unlikely(err)) {
 184                ahash_set_needkey(tfm);
 185                return err;
 186        }
 187
 188        crypto_ahash_clear_flags(tfm, CRYPTO_TFM_NEED_KEY);
 189        return 0;
 190}
 191EXPORT_SYMBOL_GPL(crypto_ahash_setkey);
 192
 193static inline unsigned int ahash_align_buffer_size(unsigned len,
 194                                                   unsigned long mask)
 195{
 196        return len + (mask & ~(crypto_tfm_ctx_alignment() - 1));
 197}
 198
 199static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt)
 200{
 201        struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 202        unsigned long alignmask = crypto_ahash_alignmask(tfm);
 203        unsigned int ds = crypto_ahash_digestsize(tfm);
 204        struct ahash_request_priv *priv;
 205
 206        priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
 207                       (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
 208                       GFP_KERNEL : GFP_ATOMIC);
 209        if (!priv)
 210                return -ENOMEM;
 211
 212        /*
 213         * WARNING: Voodoo programming below!
 214         *
 215         * The code below is obscure and hard to understand, thus explanation
 216         * is necessary. See include/crypto/hash.h and include/linux/crypto.h
 217         * to understand the layout of structures used here!
 218         *
 219         * The code here will replace portions of the ORIGINAL request with
 220         * pointers to new code and buffers so the hashing operation can store
 221         * the result in aligned buffer. We will call the modified request
 222         * an ADJUSTED request.
 223         *
 224         * The newly mangled request will look as such:
 225         *
 226         * req {
 227         *   .result        = ADJUSTED[new aligned buffer]
 228         *   .base.complete = ADJUSTED[pointer to completion function]
 229         *   .base.data     = ADJUSTED[*req (pointer to self)]
 230         *   .priv          = ADJUSTED[new priv] {
 231         *           .result   = ORIGINAL(result)
 232         *           .complete = ORIGINAL(base.complete)
 233         *           .data     = ORIGINAL(base.data)
 234         *   }
 235         */
 236
 237        priv->result = req->result;
 238        priv->complete = req->base.complete;
 239        priv->data = req->base.data;
 240        priv->flags = req->base.flags;
 241
 242        /*
 243         * WARNING: We do not backup req->priv here! The req->priv
 244         *          is for internal use of the Crypto API and the
 245         *          user must _NOT_ _EVER_ depend on it's content!
 246         */
 247
 248        req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
 249        req->base.complete = cplt;
 250        req->base.data = req;
 251        req->priv = priv;
 252
 253        return 0;
 254}
 255
 256static void ahash_restore_req(struct ahash_request *req, int err)
 257{
 258        struct ahash_request_priv *priv = req->priv;
 259
 260        if (!err)
 261                memcpy(priv->result, req->result,
 262                       crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
 263
 264        /* Restore the original crypto request. */
 265        req->result = priv->result;
 266
 267        ahash_request_set_callback(req, priv->flags,
 268                                   priv->complete, priv->data);
 269        req->priv = NULL;
 270
 271        /* Free the req->priv.priv from the ADJUSTED request. */
 272        kfree_sensitive(priv);
 273}
 274
 275static void ahash_notify_einprogress(struct ahash_request *req)
 276{
 277        struct ahash_request_priv *priv = req->priv;
 278        struct crypto_async_request oreq;
 279
 280        oreq.data = priv->data;
 281
 282        priv->complete(&oreq, -EINPROGRESS);
 283}
 284
 285static void ahash_op_unaligned_done(struct crypto_async_request *req, int err)
 286{
 287        struct ahash_request *areq = req->data;
 288
 289        if (err == -EINPROGRESS) {
 290                ahash_notify_einprogress(areq);
 291                return;
 292        }
 293
 294        /*
 295         * Restore the original request, see ahash_op_unaligned() for what
 296         * goes where.
 297         *
 298         * The "struct ahash_request *req" here is in fact the "req.base"
 299         * from the ADJUSTED request from ahash_op_unaligned(), thus as it
 300         * is a pointer to self, it is also the ADJUSTED "req" .
 301         */
 302
 303        /* First copy req->result into req->priv.result */
 304        ahash_restore_req(areq, err);
 305
 306        /* Complete the ORIGINAL request. */
 307        areq->base.complete(&areq->base, err);
 308}
 309
 310static int ahash_op_unaligned(struct ahash_request *req,
 311                              int (*op)(struct ahash_request *))
 312{
 313        int err;
 314
 315        err = ahash_save_req(req, ahash_op_unaligned_done);
 316        if (err)
 317                return err;
 318
 319        err = op(req);
 320        if (err == -EINPROGRESS || err == -EBUSY)
 321                return err;
 322
 323        ahash_restore_req(req, err);
 324
 325        return err;
 326}
 327
 328static int crypto_ahash_op(struct ahash_request *req,
 329                           int (*op)(struct ahash_request *))
 330{
 331        struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 332        unsigned long alignmask = crypto_ahash_alignmask(tfm);
 333
 334        if ((unsigned long)req->result & alignmask)
 335                return ahash_op_unaligned(req, op);
 336
 337        return op(req);
 338}
 339
 340int crypto_ahash_final(struct ahash_request *req)
 341{
 342        struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 343        struct crypto_alg *alg = tfm->base.__crt_alg;
 344        unsigned int nbytes = req->nbytes;
 345        int ret;
 346
 347        crypto_stats_get(alg);
 348        ret = crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
 349        crypto_stats_ahash_final(nbytes, ret, alg);
 350        return ret;
 351}
 352EXPORT_SYMBOL_GPL(crypto_ahash_final);
 353
 354int crypto_ahash_finup(struct ahash_request *req)
 355{
 356        struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 357        struct crypto_alg *alg = tfm->base.__crt_alg;
 358        unsigned int nbytes = req->nbytes;
 359        int ret;
 360
 361        crypto_stats_get(alg);
 362        ret = crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
 363        crypto_stats_ahash_final(nbytes, ret, alg);
 364        return ret;
 365}
 366EXPORT_SYMBOL_GPL(crypto_ahash_finup);
 367
 368int crypto_ahash_digest(struct ahash_request *req)
 369{
 370        struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 371        struct crypto_alg *alg = tfm->base.__crt_alg;
 372        unsigned int nbytes = req->nbytes;
 373        int ret;
 374
 375        crypto_stats_get(alg);
 376        if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
 377                ret = -ENOKEY;
 378        else
 379                ret = crypto_ahash_op(req, tfm->digest);
 380        crypto_stats_ahash_final(nbytes, ret, alg);
 381        return ret;
 382}
 383EXPORT_SYMBOL_GPL(crypto_ahash_digest);
 384
 385static void ahash_def_finup_done2(struct crypto_async_request *req, int err)
 386{
 387        struct ahash_request *areq = req->data;
 388
 389        if (err == -EINPROGRESS)
 390                return;
 391
 392        ahash_restore_req(areq, err);
 393
 394        areq->base.complete(&areq->base, err);
 395}
 396
 397static int ahash_def_finup_finish1(struct ahash_request *req, int err)
 398{
 399        if (err)
 400                goto out;
 401
 402        req->base.complete = ahash_def_finup_done2;
 403
 404        err = crypto_ahash_reqtfm(req)->final(req);
 405        if (err == -EINPROGRESS || err == -EBUSY)
 406                return err;
 407
 408out:
 409        ahash_restore_req(req, err);
 410        return err;
 411}
 412
 413static void ahash_def_finup_done1(struct crypto_async_request *req, int err)
 414{
 415        struct ahash_request *areq = req->data;
 416
 417        if (err == -EINPROGRESS) {
 418                ahash_notify_einprogress(areq);
 419                return;
 420        }
 421
 422        areq->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
 423
 424        err = ahash_def_finup_finish1(areq, err);
 425        if (areq->priv)
 426                return;
 427
 428        areq->base.complete(&areq->base, err);
 429}
 430
 431static int ahash_def_finup(struct ahash_request *req)
 432{
 433        struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 434        int err;
 435
 436        err = ahash_save_req(req, ahash_def_finup_done1);
 437        if (err)
 438                return err;
 439
 440        err = tfm->update(req);
 441        if (err == -EINPROGRESS || err == -EBUSY)
 442                return err;
 443
 444        return ahash_def_finup_finish1(req, err);
 445}
 446
 447static void crypto_ahash_exit_tfm(struct crypto_tfm *tfm)
 448{
 449        struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
 450        struct ahash_alg *alg = crypto_ahash_alg(hash);
 451
 452        alg->exit_tfm(hash);
 453}
 454
 455static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
 456{
 457        struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
 458        struct ahash_alg *alg = crypto_ahash_alg(hash);
 459
 460        hash->setkey = ahash_nosetkey;
 461
 462        if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
 463                return crypto_init_shash_ops_async(tfm);
 464
 465        hash->init = alg->init;
 466        hash->update = alg->update;
 467        hash->final = alg->final;
 468        hash->finup = alg->finup ?: ahash_def_finup;
 469        hash->digest = alg->digest;
 470        hash->export = alg->export;
 471        hash->import = alg->import;
 472
 473        if (alg->setkey) {
 474                hash->setkey = alg->setkey;
 475                ahash_set_needkey(hash);
 476        }
 477
 478        if (alg->exit_tfm)
 479                tfm->exit = crypto_ahash_exit_tfm;
 480
 481        return alg->init_tfm ? alg->init_tfm(hash) : 0;
 482}
 483
 484static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
 485{
 486        if (alg->cra_type != &crypto_ahash_type)
 487                return sizeof(struct crypto_shash *);
 488
 489        return crypto_alg_extsize(alg);
 490}
 491
 492static void crypto_ahash_free_instance(struct crypto_instance *inst)
 493{
 494        struct ahash_instance *ahash = ahash_instance(inst);
 495
 496        ahash->free(ahash);
 497}
 498
 499#ifdef CONFIG_NET
 500static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 501{
 502        struct crypto_report_hash rhash;
 503
 504        memset(&rhash, 0, sizeof(rhash));
 505
 506        strscpy(rhash.type, "ahash", sizeof(rhash.type));
 507
 508        rhash.blocksize = alg->cra_blocksize;
 509        rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;
 510
 511        return nla_put(skb, CRYPTOCFGA_REPORT_HASH, sizeof(rhash), &rhash);
 512}
 513#else
 514static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 515{
 516        return -ENOSYS;
 517}
 518#endif
 519
 520static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 521        __maybe_unused;
 522static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 523{
 524        seq_printf(m, "type         : ahash\n");
 525        seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 526                                             "yes" : "no");
 527        seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 528        seq_printf(m, "digestsize   : %u\n",
 529                   __crypto_hash_alg_common(alg)->digestsize);
 530}
 531
 532static const struct crypto_type crypto_ahash_type = {
 533        .extsize = crypto_ahash_extsize,
 534        .init_tfm = crypto_ahash_init_tfm,
 535        .free = crypto_ahash_free_instance,
 536#ifdef CONFIG_PROC_FS
 537        .show = crypto_ahash_show,
 538#endif
 539        .report = crypto_ahash_report,
 540        .maskclear = ~CRYPTO_ALG_TYPE_MASK,
 541        .maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
 542        .type = CRYPTO_ALG_TYPE_AHASH,
 543        .tfmsize = offsetof(struct crypto_ahash, base),
 544};
 545
 546int crypto_grab_ahash(struct crypto_ahash_spawn *spawn,
 547                      struct crypto_instance *inst,
 548                      const char *name, u32 type, u32 mask)
 549{
 550        spawn->base.frontend = &crypto_ahash_type;
 551        return crypto_grab_spawn(&spawn->base, inst, name, type, mask);
 552}
 553EXPORT_SYMBOL_GPL(crypto_grab_ahash);
 554
 555struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
 556                                        u32 mask)
 557{
 558        return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
 559}
 560EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
 561
 562int crypto_has_ahash(const char *alg_name, u32 type, u32 mask)
 563{
 564        return crypto_type_has_alg(alg_name, &crypto_ahash_type, type, mask);
 565}
 566EXPORT_SYMBOL_GPL(crypto_has_ahash);
 567
 568static int ahash_prepare_alg(struct ahash_alg *alg)
 569{
 570        struct crypto_alg *base = &alg->halg.base;
 571
 572        if (alg->halg.digestsize > HASH_MAX_DIGESTSIZE ||
 573            alg->halg.statesize > HASH_MAX_STATESIZE ||
 574            alg->halg.statesize == 0)
 575                return -EINVAL;
 576
 577        base->cra_type = &crypto_ahash_type;
 578        base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
 579        base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
 580
 581        return 0;
 582}
 583
 584int crypto_register_ahash(struct ahash_alg *alg)
 585{
 586        struct crypto_alg *base = &alg->halg.base;
 587        int err;
 588
 589        err = ahash_prepare_alg(alg);
 590        if (err)
 591                return err;
 592
 593        return crypto_register_alg(base);
 594}
 595EXPORT_SYMBOL_GPL(crypto_register_ahash);
 596
 597void crypto_unregister_ahash(struct ahash_alg *alg)
 598{
 599        crypto_unregister_alg(&alg->halg.base);
 600}
 601EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
 602
 603int crypto_register_ahashes(struct ahash_alg *algs, int count)
 604{
 605        int i, ret;
 606
 607        for (i = 0; i < count; i++) {
 608                ret = crypto_register_ahash(&algs[i]);
 609                if (ret)
 610                        goto err;
 611        }
 612
 613        return 0;
 614
 615err:
 616        for (--i; i >= 0; --i)
 617                crypto_unregister_ahash(&algs[i]);
 618
 619        return ret;
 620}
 621EXPORT_SYMBOL_GPL(crypto_register_ahashes);
 622
 623void crypto_unregister_ahashes(struct ahash_alg *algs, int count)
 624{
 625        int i;
 626
 627        for (i = count - 1; i >= 0; --i)
 628                crypto_unregister_ahash(&algs[i]);
 629}
 630EXPORT_SYMBOL_GPL(crypto_unregister_ahashes);
 631
 632int ahash_register_instance(struct crypto_template *tmpl,
 633                            struct ahash_instance *inst)
 634{
 635        int err;
 636
 637        if (WARN_ON(!inst->free))
 638                return -EINVAL;
 639
 640        err = ahash_prepare_alg(&inst->alg);
 641        if (err)
 642                return err;
 643
 644        return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
 645}
 646EXPORT_SYMBOL_GPL(ahash_register_instance);
 647
 648bool crypto_hash_alg_has_setkey(struct hash_alg_common *halg)
 649{
 650        struct crypto_alg *alg = &halg->base;
 651
 652        if (alg->cra_type != &crypto_ahash_type)
 653                return crypto_shash_alg_has_setkey(__crypto_shash_alg(alg));
 654
 655        return __crypto_ahash_alg(alg)->setkey != NULL;
 656}
 657EXPORT_SYMBOL_GPL(crypto_hash_alg_has_setkey);
 658
 659MODULE_LICENSE("GPL");
 660MODULE_DESCRIPTION("Asynchronous cryptographic hash type");
 661
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