crypto/essiv.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * ESSIV skcipher and aead template for block encryption
   4  *
   5  * This template encapsulates the ESSIV IV generation algorithm used by
   6  * dm-crypt and fscrypt, which converts the initial vector for the skcipher
   7  * used for block encryption, by encrypting it using the hash of the
   8  * skcipher key as encryption key. Usually, the input IV is a 64-bit sector
   9  * number in LE representation zero-padded to the size of the IV, but this
  10  * is not assumed by this driver.
  11  *
  12  * The typical use of this template is to instantiate the skcipher
  13  * 'essiv(cbc(aes),sha256)', which is the only instantiation used by
  14  * fscrypt, and the most relevant one for dm-crypt. However, dm-crypt
  15  * also permits ESSIV to be used in combination with the authenc template,
  16  * e.g., 'essiv(authenc(hmac(sha256),cbc(aes)),sha256)', in which case
  17  * we need to instantiate an aead that accepts the same special key format
  18  * as the authenc template, and deals with the way the encrypted IV is
  19  * embedded into the AAD area of the aead request. This means the AEAD
  20  * flavor produced by this template is tightly coupled to the way dm-crypt
  21  * happens to use it.
  22  *
  23  * Copyright (c) 2019 Linaro, Ltd. <ard.biesheuvel@linaro.org>
  24  *
  25  * Heavily based on:
  26  * adiantum length-preserving encryption mode
  27  *
  28  * Copyright 2018 Google LLC
  29  */
  30
  31 #include <crypto/authenc.h>
  32 #include <crypto/internal/aead.h>
  33 #include <crypto/internal/hash.h>
  34 #include <crypto/internal/skcipher.h>
  35 #include <crypto/scatterwalk.h>
  36 #include <linux/module.h>
  37
  38 #include "internal.h"
  39
  40 struct essiv_instance_ctx {
  41         union {
  42                 struct crypto_skcipher_spawn    skcipher_spawn;
  43                 struct crypto_aead_spawn        aead_spawn;
  44         } u;
  45         char    essiv_cipher_name[CRYPTO_MAX_ALG_NAME];
  46         char    shash_driver_name[CRYPTO_MAX_ALG_NAME];
  47 };
  48
  49 struct essiv_tfm_ctx {
  50         union {
  51                 struct crypto_skcipher  *skcipher;
  52                 struct crypto_aead      *aead;
  53         } u;
  54         struct crypto_cipher            *essiv_cipher;
  55         struct crypto_shash             *hash;
  56         int                             ivoffset;
  57 };
  58
  59 struct essiv_aead_request_ctx {
  60         struct scatterlist              sg[4];
  61         u8                              *assoc;
  62         struct aead_request             aead_req;
  63 };
  64
  65 static int essiv_skcipher_setkey(struct crypto_skcipher *tfm,
  66                                  const u8 *key, unsigned int keylen)
  67 {
  68         struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
  69         SHASH_DESC_ON_STACK(desc, tctx->hash);
  70         u8 salt[HASH_MAX_DIGESTSIZE];
  71         int err;
  72
  73         crypto_skcipher_clear_flags(tctx->u.skcipher, CRYPTO_TFM_REQ_MASK);
  74         crypto_skcipher_set_flags(tctx->u.skcipher,
  75                                   crypto_skcipher_get_flags(tfm) &
  76                                   CRYPTO_TFM_REQ_MASK);
  77         err = crypto_skcipher_setkey(tctx->u.skcipher, key, keylen);
  78         if (err)
  79                 return err;
  80
  81         desc->tfm = tctx->hash;
  82         err = crypto_shash_digest(desc, key, keylen, salt);
  83         if (err)
  84                 return err;
  85
  86         crypto_cipher_clear_flags(tctx->essiv_cipher, CRYPTO_TFM_REQ_MASK);
  87         crypto_cipher_set_flags(tctx->essiv_cipher,
  88                                 crypto_skcipher_get_flags(tfm) &
  89                                 CRYPTO_TFM_REQ_MASK);
  90         return crypto_cipher_setkey(tctx->essiv_cipher, salt,
  91                                     crypto_shash_digestsize(tctx->hash));
  92 }
  93
  94 static int essiv_aead_setkey(struct crypto_aead *tfm, const u8 *key,
  95                              unsigned int keylen)
  96 {
  97         struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
  98         SHASH_DESC_ON_STACK(desc, tctx->hash);
  99         struct crypto_authenc_keys keys;
 100         u8 salt[HASH_MAX_DIGESTSIZE];
 101         int err;
 102
 103         crypto_aead_clear_flags(tctx->u.aead, CRYPTO_TFM_REQ_MASK);
 104         crypto_aead_set_flags(tctx->u.aead, crypto_aead_get_flags(tfm) &
 105                                             CRYPTO_TFM_REQ_MASK);
 106         err = crypto_aead_setkey(tctx->u.aead, key, keylen);
 107         if (err)
 108                 return err;
 109
 110         if (crypto_authenc_extractkeys(&keys, key, keylen) != 0)
 111                 return -EINVAL;
 112
 113         desc->tfm = tctx->hash;
 114         err = crypto_shash_init(desc) ?:
 115               crypto_shash_update(desc, keys.enckey, keys.enckeylen) ?:
 116               crypto_shash_finup(desc, keys.authkey, keys.authkeylen, salt);
 117         if (err)
 118                 return err;
 119
 120         crypto_cipher_clear_flags(tctx->essiv_cipher, CRYPTO_TFM_REQ_MASK);
 121         crypto_cipher_set_flags(tctx->essiv_cipher, crypto_aead_get_flags(tfm) &
 122                                                     CRYPTO_TFM_REQ_MASK);
 123         return crypto_cipher_setkey(tctx->essiv_cipher, salt,
 124                                     crypto_shash_digestsize(tctx->hash));
 125 }
 126
 127 static int essiv_aead_setauthsize(struct crypto_aead *tfm,
 128                                   unsigned int authsize)
 129 {
 130         struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
 131
 132         return crypto_aead_setauthsize(tctx->u.aead, authsize);
 133 }
 134
 135 static void essiv_skcipher_done(struct crypto_async_request *areq, int err)
 136 {
 137         struct skcipher_request *req = areq->data;
 138
 139         skcipher_request_complete(req, err);
 140 }
 141
 142 static int essiv_skcipher_crypt(struct skcipher_request *req, bool enc)
 143 {
 144         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 145         const struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
 146         struct skcipher_request *subreq = skcipher_request_ctx(req);
 147
 148         crypto_cipher_encrypt_one(tctx->essiv_cipher, req->iv, req->iv);
 149
 150         skcipher_request_set_tfm(subreq, tctx->u.skcipher);
 151         skcipher_request_set_crypt(subreq, req->src, req->dst, req->cryptlen,
 152                                    req->iv);
 153         skcipher_request_set_callback(subreq, skcipher_request_flags(req),
 154                                       essiv_skcipher_done, req);
 155
 156         return enc ? crypto_skcipher_encrypt(subreq) :
 157                      crypto_skcipher_decrypt(subreq);
 158 }
 159
 160 static int essiv_skcipher_encrypt(struct skcipher_request *req)
 161 {
 162         return essiv_skcipher_crypt(req, true);
 163 }
 164
 165 static int essiv_skcipher_decrypt(struct skcipher_request *req)
 166 {
 167         return essiv_skcipher_crypt(req, false);
 168 }
 169
 170 static void essiv_aead_done(struct crypto_async_request *areq, int err)
 171 {
 172         struct aead_request *req = areq->data;
 173         struct essiv_aead_request_ctx *rctx = aead_request_ctx(req);
 174
 175         kfree(rctx->assoc);
 176         aead_request_complete(req, err);
 177 }
 178
 179 static int essiv_aead_crypt(struct aead_request *req, bool enc)
 180 {
 181         struct crypto_aead *tfm = crypto_aead_reqtfm(req);
 182         const struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
 183         struct essiv_aead_request_ctx *rctx = aead_request_ctx(req);
 184         struct aead_request *subreq = &rctx->aead_req;
 185         struct scatterlist *src = req->src;
 186         int err;
 187
 188         crypto_cipher_encrypt_one(tctx->essiv_cipher, req->iv, req->iv);
 189
 190         /*
 191          * dm-crypt embeds the sector number and the IV in the AAD region, so
 192          * we have to copy the converted IV into the right scatterlist before
 193          * we pass it on.
 194          */
 195         rctx->assoc = NULL;
 196         if (req->src == req->dst || !enc) {
 197                 scatterwalk_map_and_copy(req->iv, req->dst,
 198                                          req->assoclen - crypto_aead_ivsize(tfm),
 199                                          crypto_aead_ivsize(tfm), 1);
 200         } else {
 201                 u8 *iv = (u8 *)aead_request_ctx(req) + tctx->ivoffset;
 202                 int ivsize = crypto_aead_ivsize(tfm);
 203                 int ssize = req->assoclen - ivsize;
 204                 struct scatterlist *sg;
 205                 int nents;
 206
 207                 if (ssize < 0)
 208                         return -EINVAL;
 209
 210                 nents = sg_nents_for_len(req->src, ssize);
 211                 if (nents < 0)
 212                         return -EINVAL;
 213
 214                 memcpy(iv, req->iv, ivsize);
 215                 sg_init_table(rctx->sg, 4);
 216
 217                 if (unlikely(nents > 1)) {
 218                         /*
 219                          * This is a case that rarely occurs in practice, but
 220                          * for correctness, we have to deal with it nonetheless.
 221                          */
 222                         rctx->assoc = kmalloc(ssize, GFP_ATOMIC);
 223                         if (!rctx->assoc)
 224                                 return -ENOMEM;
 225
 226                         scatterwalk_map_and_copy(rctx->assoc, req->src, 0,
 227                                                  ssize, 0);
 228                         sg_set_buf(rctx->sg, rctx->assoc, ssize);
 229                 } else {
 230                         sg_set_page(rctx->sg, sg_page(req->src), ssize,
 231                                     req->src->offset);
 232                 }
 233
 234                 sg_set_buf(rctx->sg + 1, iv, ivsize);
 235                 sg = scatterwalk_ffwd(rctx->sg + 2, req->src, req->assoclen);
 236                 if (sg != rctx->sg + 2)
 237                         sg_chain(rctx->sg, 3, sg);
 238
 239                 src = rctx->sg;
 240         }
 241
 242         aead_request_set_tfm(subreq, tctx->u.aead);
 243         aead_request_set_ad(subreq, req->assoclen);
 244         aead_request_set_callback(subreq, aead_request_flags(req),
 245                                   essiv_aead_done, req);
 246         aead_request_set_crypt(subreq, src, req->dst, req->cryptlen, req->iv);
 247
 248         err = enc ? crypto_aead_encrypt(subreq) :
 249                     crypto_aead_decrypt(subreq);
 250
 251         if (rctx->assoc && err != -EINPROGRESS)
 252                 kfree(rctx->assoc);
 253         return err;
 254 }
 255
 256 static int essiv_aead_encrypt(struct aead_request *req)
 257 {
 258         return essiv_aead_crypt(req, true);
 259 }
 260
 261 static int essiv_aead_decrypt(struct aead_request *req)
 262 {
 263         return essiv_aead_crypt(req, false);
 264 }
 265
 266 static int essiv_init_tfm(struct essiv_instance_ctx *ictx,
 267                           struct essiv_tfm_ctx *tctx)
 268 {
 269         struct crypto_cipher *essiv_cipher;
 270         struct crypto_shash *hash;
 271         int err;
 272
 273         essiv_cipher = crypto_alloc_cipher(ictx->essiv_cipher_name, 0, 0);
 274         if (IS_ERR(essiv_cipher))
 275                 return PTR_ERR(essiv_cipher);
 276
 277         hash = crypto_alloc_shash(ictx->shash_driver_name, 0, 0);
 278         if (IS_ERR(hash)) {
 279                 err = PTR_ERR(hash);
 280                 goto err_free_essiv_cipher;
 281         }
 282
 283         tctx->essiv_cipher = essiv_cipher;
 284         tctx->hash = hash;
 285
 286         return 0;
 287
 288 err_free_essiv_cipher:
 289         crypto_free_cipher(essiv_cipher);
 290         return err;
 291 }
 292
 293 static int essiv_skcipher_init_tfm(struct crypto_skcipher *tfm)
 294 {
 295         struct skcipher_instance *inst = skcipher_alg_instance(tfm);
 296         struct essiv_instance_ctx *ictx = skcipher_instance_ctx(inst);
 297         struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
 298         struct crypto_skcipher *skcipher;
 299         int err;
 300
 301         skcipher = crypto_spawn_skcipher(&ictx->u.skcipher_spawn);
 302         if (IS_ERR(skcipher))
 303                 return PTR_ERR(skcipher);
 304
 305         crypto_skcipher_set_reqsize(tfm, sizeof(struct skcipher_request) +
 306                                          crypto_skcipher_reqsize(skcipher));
 307
 308         err = essiv_init_tfm(ictx, tctx);
 309         if (err) {
 310                 crypto_free_skcipher(skcipher);
 311                 return err;
 312         }
 313
 314         tctx->u.skcipher = skcipher;
 315         return 0;
 316 }
 317
 318 static int essiv_aead_init_tfm(struct crypto_aead *tfm)
 319 {
 320         struct aead_instance *inst = aead_alg_instance(tfm);
 321         struct essiv_instance_ctx *ictx = aead_instance_ctx(inst);
 322         struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
 323         struct crypto_aead *aead;
 324         unsigned int subreq_size;
 325         int err;
 326
 327         BUILD_BUG_ON(offsetofend(struct essiv_aead_request_ctx, aead_req) !=
 328                      sizeof(struct essiv_aead_request_ctx));
 329
 330         aead = crypto_spawn_aead(&ictx->u.aead_spawn);
 331         if (IS_ERR(aead))
 332                 return PTR_ERR(aead);
 333
 334         subreq_size = sizeof_field(struct essiv_aead_request_ctx, aead_req) +
 335                       crypto_aead_reqsize(aead);
 336
 337         tctx->ivoffset = offsetof(struct essiv_aead_request_ctx, aead_req) +
 338                          subreq_size;
 339         crypto_aead_set_reqsize(tfm, tctx->ivoffset + crypto_aead_ivsize(aead));
 340
 341         err = essiv_init_tfm(ictx, tctx);
 342         if (err) {
 343                 crypto_free_aead(aead);
 344                 return err;
 345         }
 346
 347         tctx->u.aead = aead;
 348         return 0;
 349 }
 350
 351 static void essiv_skcipher_exit_tfm(struct crypto_skcipher *tfm)
 352 {
 353         struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
 354
 355         crypto_free_skcipher(tctx->u.skcipher);
 356         crypto_free_cipher(tctx->essiv_cipher);
 357         crypto_free_shash(tctx->hash);
 358 }
 359
 360 static void essiv_aead_exit_tfm(struct crypto_aead *tfm)
 361 {
 362         struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
 363
 364         crypto_free_aead(tctx->u.aead);
 365         crypto_free_cipher(tctx->essiv_cipher);
 366         crypto_free_shash(tctx->hash);
 367 }
 368
 369 static void essiv_skcipher_free_instance(struct skcipher_instance *inst)
 370 {
 371         struct essiv_instance_ctx *ictx = skcipher_instance_ctx(inst);
 372
 373         crypto_drop_skcipher(&ictx->u.skcipher_spawn);
 374         kfree(inst);
 375 }
 376
 377 static void essiv_aead_free_instance(struct aead_instance *inst)
 378 {
 379         struct essiv_instance_ctx *ictx = aead_instance_ctx(inst);
 380
 381         crypto_drop_aead(&ictx->u.aead_spawn);
 382         kfree(inst);
 383 }
 384
 385 static bool parse_cipher_name(char *essiv_cipher_name, const char *cra_name)
 386 {
 387         const char *p, *q;
 388         int len;
 389
 390         /* find the last opening parens */
 391         p = strrchr(cra_name, '(');
 392         if (!p++)
 393                 return false;
 394
 395         /* find the first closing parens in the tail of the string */
 396         q = strchr(p, ')');
 397         if (!q)
 398                 return false;
 399
 400         len = q - p;
 401         if (len >= CRYPTO_MAX_ALG_NAME)
 402                 return false;
 403
 404         memcpy(essiv_cipher_name, p, len);
 405         essiv_cipher_name[len] = '\0';
 406         return true;
 407 }
 408
 409 static bool essiv_supported_algorithms(const char *essiv_cipher_name,
 410                                        struct shash_alg *hash_alg,
 411                                        int ivsize)
 412 {
 413         struct crypto_alg *alg;
 414         bool ret = false;
 415
 416         alg = crypto_alg_mod_lookup(essiv_cipher_name,
 417                                     CRYPTO_ALG_TYPE_CIPHER,
 418                                     CRYPTO_ALG_TYPE_MASK);
 419         if (IS_ERR(alg))
 420                 return false;
 421
 422         if (hash_alg->digestsize < alg->cra_cipher.cia_min_keysize ||
 423             hash_alg->digestsize > alg->cra_cipher.cia_max_keysize)
 424                 goto out;
 425
 426         if (ivsize != alg->cra_blocksize)
 427                 goto out;
 428
 429         if (crypto_shash_alg_needs_key(hash_alg))
 430                 goto out;
 431
 432         ret = true;
 433
 434 out:
 435         crypto_mod_put(alg);
 436         return ret;
 437 }
 438
 439 static int essiv_create(struct crypto_template *tmpl, struct rtattr **tb)
 440 {
 441         struct crypto_attr_type *algt;
 442         const char *inner_cipher_name;
 443         const char *shash_name;
 444         struct skcipher_instance *skcipher_inst = NULL;
 445         struct aead_instance *aead_inst = NULL;
 446         struct crypto_instance *inst;
 447         struct crypto_alg *base, *block_base;
 448         struct essiv_instance_ctx *ictx;
 449         struct skcipher_alg *skcipher_alg = NULL;
 450         struct aead_alg *aead_alg = NULL;
 451         struct crypto_alg *_hash_alg;
 452         struct shash_alg *hash_alg;
 453         int ivsize;
 454         u32 type;
 455         u32 mask;
 456         int err;
 457
 458         algt = crypto_get_attr_type(tb);
 459         if (IS_ERR(algt))
 460                 return PTR_ERR(algt);
 461
 462         inner_cipher_name = crypto_attr_alg_name(tb[1]);
 463         if (IS_ERR(inner_cipher_name))
 464                 return PTR_ERR(inner_cipher_name);
 465
 466         shash_name = crypto_attr_alg_name(tb[2]);
 467         if (IS_ERR(shash_name))
 468                 return PTR_ERR(shash_name);
 469
 470         type = algt->type & algt->mask;
 471         mask = crypto_requires_sync(algt->type, algt->mask);
 472
 473         switch (type) {
 474         case CRYPTO_ALG_TYPE_SKCIPHER:
 475                 skcipher_inst = kzalloc(sizeof(*skcipher_inst) +
 476                                         sizeof(*ictx), GFP_KERNEL);
 477                 if (!skcipher_inst)
 478                         return -ENOMEM;
 479                 inst = skcipher_crypto_instance(skcipher_inst);
 480                 base = &skcipher_inst->alg.base;
 481                 ictx = crypto_instance_ctx(inst);
 482
 483                 /* Symmetric cipher, e.g., "cbc(aes)" */
 484                 err = crypto_grab_skcipher(&ictx->u.skcipher_spawn, inst,
 485                                            inner_cipher_name, 0, mask);
 486                 if (err)
 487                         goto out_free_inst;
 488                 skcipher_alg = crypto_spawn_skcipher_alg(&ictx->u.skcipher_spawn);
 489                 block_base = &skcipher_alg->base;
 490                 ivsize = crypto_skcipher_alg_ivsize(skcipher_alg);
 491                 break;
 492
 493         case CRYPTO_ALG_TYPE_AEAD:
 494                 aead_inst = kzalloc(sizeof(*aead_inst) +
 495                                     sizeof(*ictx), GFP_KERNEL);
 496                 if (!aead_inst)
 497                         return -ENOMEM;
 498                 inst = aead_crypto_instance(aead_inst);
 499                 base = &aead_inst->alg.base;
 500                 ictx = crypto_instance_ctx(inst);
 501
 502                 /* AEAD cipher, e.g., "authenc(hmac(sha256),cbc(aes))" */
 503                 err = crypto_grab_aead(&ictx->u.aead_spawn, inst,
 504                                        inner_cipher_name, 0, mask);
 505                 if (err)
 506                         goto out_free_inst;
 507                 aead_alg = crypto_spawn_aead_alg(&ictx->u.aead_spawn);
 508                 block_base = &aead_alg->base;
 509                 if (!strstarts(block_base->cra_name, "authenc(")) {
 510                         pr_warn("Only authenc() type AEADs are supported by ESSIV\n");
 511                         err = -EINVAL;
 512                         goto out_drop_skcipher;
 513                 }
 514                 ivsize = aead_alg->ivsize;
 515                 break;
 516
 517         default:
 518                 return -EINVAL;
 519         }
 520
 521         if (!parse_cipher_name(ictx->essiv_cipher_name, block_base->cra_name)) {
 522                 pr_warn("Failed to parse ESSIV cipher name from skcipher cra_name\n");
 523                 err = -EINVAL;
 524                 goto out_drop_skcipher;
 525         }
 526
 527         /* Synchronous hash, e.g., "sha256" */
 528         _hash_alg = crypto_alg_mod_lookup(shash_name,
 529                                           CRYPTO_ALG_TYPE_SHASH,
 530                                           CRYPTO_ALG_TYPE_MASK);
 531         if (IS_ERR(_hash_alg)) {
 532                 err = PTR_ERR(_hash_alg);
 533                 goto out_drop_skcipher;
 534         }
 535         hash_alg = __crypto_shash_alg(_hash_alg);
 536
 537         /* Check the set of algorithms */
 538         if (!essiv_supported_algorithms(ictx->essiv_cipher_name, hash_alg,
 539                                         ivsize)) {
 540                 pr_warn("Unsupported essiv instantiation: essiv(%s,%s)\n",
 541                         block_base->cra_name, hash_alg->base.cra_name);
 542                 err = -EINVAL;
 543                 goto out_free_hash;
 544         }
 545
 546         /* record the driver name so we can instantiate this exact algo later */
 547         strlcpy(ictx->shash_driver_name, hash_alg->base.cra_driver_name,
 548                 CRYPTO_MAX_ALG_NAME);
 549
 550         /* Instance fields */
 551
 552         err = -ENAMETOOLONG;
 553         if (snprintf(base->cra_name, CRYPTO_MAX_ALG_NAME,
 554                      "essiv(%s,%s)", block_base->cra_name,
 555                      hash_alg->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
 556                 goto out_free_hash;
 557         if (snprintf(base->cra_driver_name, CRYPTO_MAX_ALG_NAME,
 558                      "essiv(%s,%s)", block_base->cra_driver_name,
 559                      hash_alg->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
 560                 goto out_free_hash;
 561
 562         base->cra_flags         = block_base->cra_flags & CRYPTO_ALG_ASYNC;
 563         base->cra_blocksize     = block_base->cra_blocksize;
 564         base->cra_ctxsize       = sizeof(struct essiv_tfm_ctx);
 565         base->cra_alignmask     = block_base->cra_alignmask;
 566         base->cra_priority      = block_base->cra_priority;
 567
 568         if (type == CRYPTO_ALG_TYPE_SKCIPHER) {
 569                 skcipher_inst->alg.setkey       = essiv_skcipher_setkey;
 570                 skcipher_inst->alg.encrypt      = essiv_skcipher_encrypt;
 571                 skcipher_inst->alg.decrypt      = essiv_skcipher_decrypt;
 572                 skcipher_inst->alg.init         = essiv_skcipher_init_tfm;
 573                 skcipher_inst->alg.exit         = essiv_skcipher_exit_tfm;
 574
 575                 skcipher_inst->alg.min_keysize  = crypto_skcipher_alg_min_keysize(skcipher_alg);
 576                 skcipher_inst->alg.max_keysize  = crypto_skcipher_alg_max_keysize(skcipher_alg);
 577                 skcipher_inst->alg.ivsize       = ivsize;
 578                 skcipher_inst->alg.chunksize    = crypto_skcipher_alg_chunksize(skcipher_alg);
 579                 skcipher_inst->alg.walksize     = crypto_skcipher_alg_walksize(skcipher_alg);
 580
 581                 skcipher_inst->free             = essiv_skcipher_free_instance;
 582
 583                 err = skcipher_register_instance(tmpl, skcipher_inst);
 584         } else {
 585                 aead_inst->alg.setkey           = essiv_aead_setkey;
 586                 aead_inst->alg.setauthsize      = essiv_aead_setauthsize;
 587                 aead_inst->alg.encrypt          = essiv_aead_encrypt;
 588                 aead_inst->alg.decrypt          = essiv_aead_decrypt;
 589                 aead_inst->alg.init             = essiv_aead_init_tfm;
 590                 aead_inst->alg.exit             = essiv_aead_exit_tfm;
 591
 592                 aead_inst->alg.ivsize           = ivsize;
 593                 aead_inst->alg.maxauthsize      = crypto_aead_alg_maxauthsize(aead_alg);
 594                 aead_inst->alg.chunksize        = crypto_aead_alg_chunksize(aead_alg);
 595
 596                 aead_inst->free                 = essiv_aead_free_instance;
 597
 598                 err = aead_register_instance(tmpl, aead_inst);
 599         }
 600
 601         if (err)
 602                 goto out_free_hash;
 603
 604         crypto_mod_put(_hash_alg);
 605         return 0;
 606
 607 out_free_hash:
 608         crypto_mod_put(_hash_alg);
 609 out_drop_skcipher:
 610         if (type == CRYPTO_ALG_TYPE_SKCIPHER)
 611                 crypto_drop_skcipher(&ictx->u.skcipher_spawn);
 612         else
 613                 crypto_drop_aead(&ictx->u.aead_spawn);
 614 out_free_inst:
 615         kfree(skcipher_inst);
 616         kfree(aead_inst);
 617         return err;
 618 }
 619
 620 /* essiv(cipher_name, shash_name) */
 621 static struct crypto_template essiv_tmpl = {
 622         .name   = "essiv",
 623         .create = essiv_create,
 624         .module = THIS_MODULE,
 625 };
 626
 627 static int __init essiv_module_init(void)
 628 {
 629         return crypto_register_template(&essiv_tmpl);
 630 }
 631
 632 static void __exit essiv_module_exit(void)
 633 {
 634         crypto_unregister_template(&essiv_tmpl);
 635 }
 636
 637 subsys_initcall(essiv_module_init);
 638 module_exit(essiv_module_exit);
 639
 640 MODULE_DESCRIPTION("ESSIV skcipher/aead wrapper for block encryption");
 641 MODULE_LICENSE("GPL v2");
 642 MODULE_ALIAS_CRYPTO("essiv");