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         crypto_skcipher_set_flags(tfm,
  79                                   crypto_skcipher_get_flags(tctx->u.skcipher) &
  80                                   CRYPTO_TFM_RES_MASK);
  81         if (err)
  82                 return err;
  83
  84         desc->tfm = tctx->hash;
  85         err = crypto_shash_digest(desc, key, keylen, salt);
  86         if (err)
  87                 return err;
  88
  89         crypto_cipher_clear_flags(tctx->essiv_cipher, CRYPTO_TFM_REQ_MASK);
  90         crypto_cipher_set_flags(tctx->essiv_cipher,
  91                                 crypto_skcipher_get_flags(tfm) &
  92                                 CRYPTO_TFM_REQ_MASK);
  93         err = crypto_cipher_setkey(tctx->essiv_cipher, salt,
  94                                    crypto_shash_digestsize(tctx->hash));
  95         crypto_skcipher_set_flags(tfm,
  96                                   crypto_cipher_get_flags(tctx->essiv_cipher) &
  97                                   CRYPTO_TFM_RES_MASK);
  98
  99         return err;
 100 }
 101
 102 static int essiv_aead_setkey(struct crypto_aead *tfm, const u8 *key,
 103                              unsigned int keylen)
 104 {
 105         struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
 106         SHASH_DESC_ON_STACK(desc, tctx->hash);
 107         struct crypto_authenc_keys keys;
 108         u8 salt[HASH_MAX_DIGESTSIZE];
 109         int err;
 110
 111         crypto_aead_clear_flags(tctx->u.aead, CRYPTO_TFM_REQ_MASK);
 112         crypto_aead_set_flags(tctx->u.aead, crypto_aead_get_flags(tfm) &
 113                                             CRYPTO_TFM_REQ_MASK);
 114         err = crypto_aead_setkey(tctx->u.aead, key, keylen);
 115         crypto_aead_set_flags(tfm, crypto_aead_get_flags(tctx->u.aead) &
 116                                    CRYPTO_TFM_RES_MASK);
 117         if (err)
 118                 return err;
 119
 120         if (crypto_authenc_extractkeys(&keys, key, keylen) != 0) {
 121                 crypto_aead_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
 122                 return -EINVAL;
 123         }
 124
 125         desc->tfm = tctx->hash;
 126         err = crypto_shash_init(desc) ?:
 127               crypto_shash_update(desc, keys.enckey, keys.enckeylen) ?:
 128               crypto_shash_finup(desc, keys.authkey, keys.authkeylen, salt);
 129         if (err)
 130                 return err;
 131
 132         crypto_cipher_clear_flags(tctx->essiv_cipher, CRYPTO_TFM_REQ_MASK);
 133         crypto_cipher_set_flags(tctx->essiv_cipher, crypto_aead_get_flags(tfm) &
 134                                                     CRYPTO_TFM_REQ_MASK);
 135         err = crypto_cipher_setkey(tctx->essiv_cipher, salt,
 136                                    crypto_shash_digestsize(tctx->hash));
 137         crypto_aead_set_flags(tfm, crypto_cipher_get_flags(tctx->essiv_cipher) &
 138                                    CRYPTO_TFM_RES_MASK);
 139
 140         return err;
 141 }
 142
 143 static int essiv_aead_setauthsize(struct crypto_aead *tfm,
 144                                   unsigned int authsize)
 145 {
 146         struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
 147
 148         return crypto_aead_setauthsize(tctx->u.aead, authsize);
 149 }
 150
 151 static void essiv_skcipher_done(struct crypto_async_request *areq, int err)
 152 {
 153         struct skcipher_request *req = areq->data;
 154
 155         skcipher_request_complete(req, err);
 156 }
 157
 158 static int essiv_skcipher_crypt(struct skcipher_request *req, bool enc)
 159 {
 160         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 161         const struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
 162         struct skcipher_request *subreq = skcipher_request_ctx(req);
 163
 164         crypto_cipher_encrypt_one(tctx->essiv_cipher, req->iv, req->iv);
 165
 166         skcipher_request_set_tfm(subreq, tctx->u.skcipher);
 167         skcipher_request_set_crypt(subreq, req->src, req->dst, req->cryptlen,
 168                                    req->iv);
 169         skcipher_request_set_callback(subreq, skcipher_request_flags(req),
 170                                       essiv_skcipher_done, req);
 171
 172         return enc ? crypto_skcipher_encrypt(subreq) :
 173                      crypto_skcipher_decrypt(subreq);
 174 }
 175
 176 static int essiv_skcipher_encrypt(struct skcipher_request *req)
 177 {
 178         return essiv_skcipher_crypt(req, true);
 179 }
 180
 181 static int essiv_skcipher_decrypt(struct skcipher_request *req)
 182 {
 183         return essiv_skcipher_crypt(req, false);
 184 }
 185
 186 static void essiv_aead_done(struct crypto_async_request *areq, int err)
 187 {
 188         struct aead_request *req = areq->data;
 189         struct essiv_aead_request_ctx *rctx = aead_request_ctx(req);
 190
 191         kfree(rctx->assoc);
 192         aead_request_complete(req, err);
 193 }
 194
 195 static int essiv_aead_crypt(struct aead_request *req, bool enc)
 196 {
 197         struct crypto_aead *tfm = crypto_aead_reqtfm(req);
 198         const struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
 199         struct essiv_aead_request_ctx *rctx = aead_request_ctx(req);
 200         struct aead_request *subreq = &rctx->aead_req;
 201         struct scatterlist *src = req->src;
 202         int err;
 203
 204         crypto_cipher_encrypt_one(tctx->essiv_cipher, req->iv, req->iv);
 205
 206         /*
 207          * dm-crypt embeds the sector number and the IV in the AAD region, so
 208          * we have to copy the converted IV into the right scatterlist before
 209          * we pass it on.
 210          */
 211         rctx->assoc = NULL;
 212         if (req->src == req->dst || !enc) {
 213                 scatterwalk_map_and_copy(req->iv, req->dst,
 214                                          req->assoclen - crypto_aead_ivsize(tfm),
 215                                          crypto_aead_ivsize(tfm), 1);
 216         } else {
 217                 u8 *iv = (u8 *)aead_request_ctx(req) + tctx->ivoffset;
 218                 int ivsize = crypto_aead_ivsize(tfm);
 219                 int ssize = req->assoclen - ivsize;
 220                 struct scatterlist *sg;
 221                 int nents;
 222
 223                 if (ssize < 0)
 224                         return -EINVAL;
 225
 226                 nents = sg_nents_for_len(req->src, ssize);
 227                 if (nents < 0)
 228                         return -EINVAL;
 229
 230                 memcpy(iv, req->iv, ivsize);
 231                 sg_init_table(rctx->sg, 4);
 232
 233                 if (unlikely(nents > 1)) {
 234                         /*
 235                          * This is a case that rarely occurs in practice, but
 236                          * for correctness, we have to deal with it nonetheless.
 237                          */
 238                         rctx->assoc = kmalloc(ssize, GFP_ATOMIC);
 239                         if (!rctx->assoc)
 240                                 return -ENOMEM;
 241
 242                         scatterwalk_map_and_copy(rctx->assoc, req->src, 0,
 243                                                  ssize, 0);
 244                         sg_set_buf(rctx->sg, rctx->assoc, ssize);
 245                 } else {
 246                         sg_set_page(rctx->sg, sg_page(req->src), ssize,
 247                                     req->src->offset);
 248                 }
 249
 250                 sg_set_buf(rctx->sg + 1, iv, ivsize);
 251                 sg = scatterwalk_ffwd(rctx->sg + 2, req->src, req->assoclen);
 252                 if (sg != rctx->sg + 2)
 253                         sg_chain(rctx->sg, 3, sg);
 254
 255                 src = rctx->sg;
 256         }
 257
 258         aead_request_set_tfm(subreq, tctx->u.aead);
 259         aead_request_set_ad(subreq, req->assoclen);
 260         aead_request_set_callback(subreq, aead_request_flags(req),
 261                                   essiv_aead_done, req);
 262         aead_request_set_crypt(subreq, src, req->dst, req->cryptlen, req->iv);
 263
 264         err = enc ? crypto_aead_encrypt(subreq) :
 265                     crypto_aead_decrypt(subreq);
 266
 267         if (rctx->assoc && err != -EINPROGRESS)
 268                 kfree(rctx->assoc);
 269         return err;
 270 }
 271
 272 static int essiv_aead_encrypt(struct aead_request *req)
 273 {
 274         return essiv_aead_crypt(req, true);
 275 }
 276
 277 static int essiv_aead_decrypt(struct aead_request *req)
 278 {
 279         return essiv_aead_crypt(req, false);
 280 }
 281
 282 static int essiv_init_tfm(struct essiv_instance_ctx *ictx,
 283                           struct essiv_tfm_ctx *tctx)
 284 {
 285         struct crypto_cipher *essiv_cipher;
 286         struct crypto_shash *hash;
 287         int err;
 288
 289         essiv_cipher = crypto_alloc_cipher(ictx->essiv_cipher_name, 0, 0);
 290         if (IS_ERR(essiv_cipher))
 291                 return PTR_ERR(essiv_cipher);
 292
 293         hash = crypto_alloc_shash(ictx->shash_driver_name, 0, 0);
 294         if (IS_ERR(hash)) {
 295                 err = PTR_ERR(hash);
 296                 goto err_free_essiv_cipher;
 297         }
 298
 299         tctx->essiv_cipher = essiv_cipher;
 300         tctx->hash = hash;
 301
 302         return 0;
 303
 304 err_free_essiv_cipher:
 305         crypto_free_cipher(essiv_cipher);
 306         return err;
 307 }
 308
 309 static int essiv_skcipher_init_tfm(struct crypto_skcipher *tfm)
 310 {
 311         struct skcipher_instance *inst = skcipher_alg_instance(tfm);
 312         struct essiv_instance_ctx *ictx = skcipher_instance_ctx(inst);
 313         struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
 314         struct crypto_skcipher *skcipher;
 315         int err;
 316
 317         skcipher = crypto_spawn_skcipher(&ictx->u.skcipher_spawn);
 318         if (IS_ERR(skcipher))
 319                 return PTR_ERR(skcipher);
 320
 321         crypto_skcipher_set_reqsize(tfm, sizeof(struct skcipher_request) +
 322                                          crypto_skcipher_reqsize(skcipher));
 323
 324         err = essiv_init_tfm(ictx, tctx);
 325         if (err) {
 326                 crypto_free_skcipher(skcipher);
 327                 return err;
 328         }
 329
 330         tctx->u.skcipher = skcipher;
 331         return 0;
 332 }
 333
 334 static int essiv_aead_init_tfm(struct crypto_aead *tfm)
 335 {
 336         struct aead_instance *inst = aead_alg_instance(tfm);
 337         struct essiv_instance_ctx *ictx = aead_instance_ctx(inst);
 338         struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
 339         struct crypto_aead *aead;
 340         unsigned int subreq_size;
 341         int err;
 342
 343         BUILD_BUG_ON(offsetofend(struct essiv_aead_request_ctx, aead_req) !=
 344                      sizeof(struct essiv_aead_request_ctx));
 345
 346         aead = crypto_spawn_aead(&ictx->u.aead_spawn);
 347         if (IS_ERR(aead))
 348                 return PTR_ERR(aead);
 349
 350         subreq_size = FIELD_SIZEOF(struct essiv_aead_request_ctx, aead_req) +
 351                       crypto_aead_reqsize(aead);
 352
 353         tctx->ivoffset = offsetof(struct essiv_aead_request_ctx, aead_req) +
 354                          subreq_size;
 355         crypto_aead_set_reqsize(tfm, tctx->ivoffset + crypto_aead_ivsize(aead));
 356
 357         err = essiv_init_tfm(ictx, tctx);
 358         if (err) {
 359                 crypto_free_aead(aead);
 360                 return err;
 361         }
 362
 363         tctx->u.aead = aead;
 364         return 0;
 365 }
 366
 367 static void essiv_skcipher_exit_tfm(struct crypto_skcipher *tfm)
 368 {
 369         struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
 370
 371         crypto_free_skcipher(tctx->u.skcipher);
 372         crypto_free_cipher(tctx->essiv_cipher);
 373         crypto_free_shash(tctx->hash);
 374 }
 375
 376 static void essiv_aead_exit_tfm(struct crypto_aead *tfm)
 377 {
 378         struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
 379
 380         crypto_free_aead(tctx->u.aead);
 381         crypto_free_cipher(tctx->essiv_cipher);
 382         crypto_free_shash(tctx->hash);
 383 }
 384
 385 static void essiv_skcipher_free_instance(struct skcipher_instance *inst)
 386 {
 387         struct essiv_instance_ctx *ictx = skcipher_instance_ctx(inst);
 388
 389         crypto_drop_skcipher(&ictx->u.skcipher_spawn);
 390         kfree(inst);
 391 }
 392
 393 static void essiv_aead_free_instance(struct aead_instance *inst)
 394 {
 395         struct essiv_instance_ctx *ictx = aead_instance_ctx(inst);
 396
 397         crypto_drop_aead(&ictx->u.aead_spawn);
 398         kfree(inst);
 399 }
 400
 401 static bool parse_cipher_name(char *essiv_cipher_name, const char *cra_name)
 402 {
 403         const char *p, *q;
 404         int len;
 405
 406         /* find the last opening parens */
 407         p = strrchr(cra_name, '(');
 408         if (!p++)
 409                 return false;
 410
 411         /* find the first closing parens in the tail of the string */
 412         q = strchr(p, ')');
 413         if (!q)
 414                 return false;
 415
 416         len = q - p;
 417         if (len >= CRYPTO_MAX_ALG_NAME)
 418                 return false;
 419
 420         memcpy(essiv_cipher_name, p, len);
 421         essiv_cipher_name[len] = '\0';
 422         return true;
 423 }
 424
 425 static bool essiv_supported_algorithms(const char *essiv_cipher_name,
 426                                        struct shash_alg *hash_alg,
 427                                        int ivsize)
 428 {
 429         struct crypto_alg *alg;
 430         bool ret = false;
 431
 432         alg = crypto_alg_mod_lookup(essiv_cipher_name,
 433                                     CRYPTO_ALG_TYPE_CIPHER,
 434                                     CRYPTO_ALG_TYPE_MASK);
 435         if (IS_ERR(alg))
 436                 return false;
 437
 438         if (hash_alg->digestsize < alg->cra_cipher.cia_min_keysize ||
 439             hash_alg->digestsize > alg->cra_cipher.cia_max_keysize)
 440                 goto out;
 441
 442         if (ivsize != alg->cra_blocksize)
 443                 goto out;
 444
 445         if (crypto_shash_alg_has_setkey(hash_alg))
 446                 goto out;
 447
 448         ret = true;
 449
 450 out:
 451         crypto_mod_put(alg);
 452         return ret;
 453 }
 454
 455 static int essiv_create(struct crypto_template *tmpl, struct rtattr **tb)
 456 {
 457         struct crypto_attr_type *algt;
 458         const char *inner_cipher_name;
 459         const char *shash_name;
 460         struct skcipher_instance *skcipher_inst = NULL;
 461         struct aead_instance *aead_inst = NULL;
 462         struct crypto_instance *inst;
 463         struct crypto_alg *base, *block_base;
 464         struct essiv_instance_ctx *ictx;
 465         struct skcipher_alg *skcipher_alg = NULL;
 466         struct aead_alg *aead_alg = NULL;
 467         struct crypto_alg *_hash_alg;
 468         struct shash_alg *hash_alg;
 469         int ivsize;
 470         u32 type;
 471         int err;
 472
 473         algt = crypto_get_attr_type(tb);
 474         if (IS_ERR(algt))
 475                 return PTR_ERR(algt);
 476
 477         inner_cipher_name = crypto_attr_alg_name(tb[1]);
 478         if (IS_ERR(inner_cipher_name))
 479                 return PTR_ERR(inner_cipher_name);
 480
 481         shash_name = crypto_attr_alg_name(tb[2]);
 482         if (IS_ERR(shash_name))
 483                 return PTR_ERR(shash_name);
 484
 485         type = algt->type & algt->mask;
 486
 487         switch (type) {
 488         case CRYPTO_ALG_TYPE_SKCIPHER:
 489                 skcipher_inst = kzalloc(sizeof(*skcipher_inst) +
 490                                         sizeof(*ictx), GFP_KERNEL);
 491                 if (!skcipher_inst)
 492                         return -ENOMEM;
 493                 inst = skcipher_crypto_instance(skcipher_inst);
 494                 base = &skcipher_inst->alg.base;
 495                 ictx = crypto_instance_ctx(inst);
 496
 497                 /* Symmetric cipher, e.g., "cbc(aes)" */
 498                 crypto_set_skcipher_spawn(&ictx->u.skcipher_spawn, inst);
 499                 err = crypto_grab_skcipher(&ictx->u.skcipher_spawn,
 500                                            inner_cipher_name, 0,
 501                                            crypto_requires_sync(algt->type,
 502                                                                 algt->mask));
 503                 if (err)
 504                         goto out_free_inst;
 505                 skcipher_alg = crypto_spawn_skcipher_alg(&ictx->u.skcipher_spawn);
 506                 block_base = &skcipher_alg->base;
 507                 ivsize = crypto_skcipher_alg_ivsize(skcipher_alg);
 508                 break;
 509
 510         case CRYPTO_ALG_TYPE_AEAD:
 511                 aead_inst = kzalloc(sizeof(*aead_inst) +
 512                                     sizeof(*ictx), GFP_KERNEL);
 513                 if (!aead_inst)
 514                         return -ENOMEM;
 515                 inst = aead_crypto_instance(aead_inst);
 516                 base = &aead_inst->alg.base;
 517                 ictx = crypto_instance_ctx(inst);
 518
 519                 /* AEAD cipher, e.g., "authenc(hmac(sha256),cbc(aes))" */
 520                 crypto_set_aead_spawn(&ictx->u.aead_spawn, inst);
 521                 err = crypto_grab_aead(&ictx->u.aead_spawn,
 522                                        inner_cipher_name, 0,
 523                                        crypto_requires_sync(algt->type,
 524                                                             algt->mask));
 525                 if (err)
 526                         goto out_free_inst;
 527                 aead_alg = crypto_spawn_aead_alg(&ictx->u.aead_spawn);
 528                 block_base = &aead_alg->base;
 529                 if (!strstarts(block_base->cra_name, "authenc(")) {
 530                         pr_warn("Only authenc() type AEADs are supported by ESSIV\n");
 531                         err = -EINVAL;
 532                         goto out_drop_skcipher;
 533                 }
 534                 ivsize = aead_alg->ivsize;
 535                 break;
 536
 537         default:
 538                 return -EINVAL;
 539         }
 540
 541         if (!parse_cipher_name(ictx->essiv_cipher_name, block_base->cra_name)) {
 542                 pr_warn("Failed to parse ESSIV cipher name from skcipher cra_name\n");
 543                 err = -EINVAL;
 544                 goto out_drop_skcipher;
 545         }
 546
 547         /* Synchronous hash, e.g., "sha256" */
 548         _hash_alg = crypto_alg_mod_lookup(shash_name,
 549                                           CRYPTO_ALG_TYPE_SHASH,
 550                                           CRYPTO_ALG_TYPE_MASK);
 551         if (IS_ERR(_hash_alg)) {
 552                 err = PTR_ERR(_hash_alg);
 553                 goto out_drop_skcipher;
 554         }
 555         hash_alg = __crypto_shash_alg(_hash_alg);
 556
 557         /* Check the set of algorithms */
 558         if (!essiv_supported_algorithms(ictx->essiv_cipher_name, hash_alg,
 559                                         ivsize)) {
 560                 pr_warn("Unsupported essiv instantiation: essiv(%s,%s)\n",
 561                         block_base->cra_name, hash_alg->base.cra_name);
 562                 err = -EINVAL;
 563                 goto out_free_hash;
 564         }
 565
 566         /* record the driver name so we can instantiate this exact algo later */
 567         strlcpy(ictx->shash_driver_name, hash_alg->base.cra_driver_name,
 568                 CRYPTO_MAX_ALG_NAME);
 569
 570         /* Instance fields */
 571
 572         err = -ENAMETOOLONG;
 573         if (snprintf(base->cra_name, CRYPTO_MAX_ALG_NAME,
 574                      "essiv(%s,%s)", block_base->cra_name,
 575                      hash_alg->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
 576                 goto out_free_hash;
 577         if (snprintf(base->cra_driver_name, CRYPTO_MAX_ALG_NAME,
 578                      "essiv(%s,%s)", block_base->cra_driver_name,
 579                      hash_alg->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
 580                 goto out_free_hash;
 581
 582         base->cra_flags         = block_base->cra_flags & CRYPTO_ALG_ASYNC;
 583         base->cra_blocksize     = block_base->cra_blocksize;
 584         base->cra_ctxsize       = sizeof(struct essiv_tfm_ctx);
 585         base->cra_alignmask     = block_base->cra_alignmask;
 586         base->cra_priority      = block_base->cra_priority;
 587
 588         if (type == CRYPTO_ALG_TYPE_SKCIPHER) {
 589                 skcipher_inst->alg.setkey       = essiv_skcipher_setkey;
 590                 skcipher_inst->alg.encrypt      = essiv_skcipher_encrypt;
 591                 skcipher_inst->alg.decrypt      = essiv_skcipher_decrypt;
 592                 skcipher_inst->alg.init         = essiv_skcipher_init_tfm;
 593                 skcipher_inst->alg.exit         = essiv_skcipher_exit_tfm;
 594
 595                 skcipher_inst->alg.min_keysize  = crypto_skcipher_alg_min_keysize(skcipher_alg);
 596                 skcipher_inst->alg.max_keysize  = crypto_skcipher_alg_max_keysize(skcipher_alg);
 597                 skcipher_inst->alg.ivsize       = ivsize;
 598                 skcipher_inst->alg.chunksize    = crypto_skcipher_alg_chunksize(skcipher_alg);
 599                 skcipher_inst->alg.walksize     = crypto_skcipher_alg_walksize(skcipher_alg);
 600
 601                 skcipher_inst->free             = essiv_skcipher_free_instance;
 602
 603                 err = skcipher_register_instance(tmpl, skcipher_inst);
 604         } else {
 605                 aead_inst->alg.setkey           = essiv_aead_setkey;
 606                 aead_inst->alg.setauthsize      = essiv_aead_setauthsize;
 607                 aead_inst->alg.encrypt          = essiv_aead_encrypt;
 608                 aead_inst->alg.decrypt          = essiv_aead_decrypt;
 609                 aead_inst->alg.init             = essiv_aead_init_tfm;
 610                 aead_inst->alg.exit             = essiv_aead_exit_tfm;
 611
 612                 aead_inst->alg.ivsize           = ivsize;
 613                 aead_inst->alg.maxauthsize      = crypto_aead_alg_maxauthsize(aead_alg);
 614                 aead_inst->alg.chunksize        = crypto_aead_alg_chunksize(aead_alg);
 615
 616                 aead_inst->free                 = essiv_aead_free_instance;
 617
 618                 err = aead_register_instance(tmpl, aead_inst);
 619         }
 620
 621         if (err)
 622                 goto out_free_hash;
 623
 624         crypto_mod_put(_hash_alg);
 625         return 0;
 626
 627 out_free_hash:
 628         crypto_mod_put(_hash_alg);
 629 out_drop_skcipher:
 630         if (type == CRYPTO_ALG_TYPE_SKCIPHER)
 631                 crypto_drop_skcipher(&ictx->u.skcipher_spawn);
 632         else
 633                 crypto_drop_aead(&ictx->u.aead_spawn);
 634 out_free_inst:
 635         kfree(skcipher_inst);
 636         kfree(aead_inst);
 637         return err;
 638 }
 639
 640 /* essiv(cipher_name, shash_name) */
 641 static struct crypto_template essiv_tmpl = {
 642         .name   = "essiv",
 643         .create = essiv_create,
 644         .module = THIS_MODULE,
 645 };
 646
 647 static int __init essiv_module_init(void)
 648 {
 649         return crypto_register_template(&essiv_tmpl);
 650 }
 651
 652 static void __exit essiv_module_exit(void)
 653 {
 654         crypto_unregister_template(&essiv_tmpl);
 655 }
 656
 657 subsys_initcall(essiv_module_init);
 658 module_exit(essiv_module_exit);
 659
 660 MODULE_DESCRIPTION("ESSIV skcipher/aead wrapper for block encryption");
 661 MODULE_LICENSE("GPL v2");
 662 MODULE_ALIAS_CRYPTO("essiv");