the-tree/crypto/essiv.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * ESSIV skcipher and aead template for block encryption
0004  *
0005  * This template encapsulates the ESSIV IV generation algorithm used by
0006  * dm-crypt and fscrypt, which converts the initial vector for the skcipher
0007  * used for block encryption, by encrypting it using the hash of the
0008  * skcipher key as encryption key. Usually, the input IV is a 64-bit sector
0009  * number in LE representation zero-padded to the size of the IV, but this
0010  * is not assumed by this driver.
0011  *
0012  * The typical use of this template is to instantiate the skcipher
0013  * 'essiv(cbc(aes),sha256)', which is the only instantiation used by
0014  * fscrypt, and the most relevant one for dm-crypt. However, dm-crypt
0015  * also permits ESSIV to be used in combination with the authenc template,
0016  * e.g., 'essiv(authenc(hmac(sha256),cbc(aes)),sha256)', in which case
0017  * we need to instantiate an aead that accepts the same special key format
0018  * as the authenc template, and deals with the way the encrypted IV is
0019  * embedded into the AAD area of the aead request. This means the AEAD
0020  * flavor produced by this template is tightly coupled to the way dm-crypt
0021  * happens to use it.
0022  *
0023  * Copyright (c) 2019 Linaro, Ltd. <ard.biesheuvel@linaro.org>
0024  *
0025  * Heavily based on:
0026  * adiantum length-preserving encryption mode
0027  *
0028  * Copyright 2018 Google LLC
0029  */
0030
0031 #include <crypto/authenc.h>
0032 #include <crypto/internal/aead.h>
0033 #include <crypto/internal/cipher.h>
0034 #include <crypto/internal/hash.h>
0035 #include <crypto/internal/skcipher.h>
0036 #include <crypto/scatterwalk.h>
0037 #include <linux/module.h>
0038
0039 #include "internal.h"
0040
0041 struct essiv_instance_ctx {
0042     union {
0043         struct crypto_skcipher_spawn    skcipher_spawn;
0044         struct crypto_aead_spawn    aead_spawn;
0045     } u;
0046     char    essiv_cipher_name[CRYPTO_MAX_ALG_NAME];
0047     char    shash_driver_name[CRYPTO_MAX_ALG_NAME];
0048 };
0049
0050 struct essiv_tfm_ctx {
0051     union {
0052         struct crypto_skcipher  *skcipher;
0053         struct crypto_aead  *aead;
0054     } u;
0055     struct crypto_cipher        *essiv_cipher;
0056     struct crypto_shash     *hash;
0057     int             ivoffset;
0058 };
0059
0060 struct essiv_aead_request_ctx {
0061     struct scatterlist      sg[4];
0062     u8              *assoc;
0063     struct aead_request     aead_req;
0064 };
0065
0066 static int essiv_skcipher_setkey(struct crypto_skcipher *tfm,
0067                  const u8 *key, unsigned int keylen)
0068 {
0069     struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
0070     u8 salt[HASH_MAX_DIGESTSIZE];
0071     int err;
0072
0073     crypto_skcipher_clear_flags(tctx->u.skcipher, CRYPTO_TFM_REQ_MASK);
0074     crypto_skcipher_set_flags(tctx->u.skcipher,
0075                   crypto_skcipher_get_flags(tfm) &
0076                   CRYPTO_TFM_REQ_MASK);
0077     err = crypto_skcipher_setkey(tctx->u.skcipher, key, keylen);
0078     if (err)
0079         return err;
0080
0081     err = crypto_shash_tfm_digest(tctx->hash, key, keylen, salt);
0082     if (err)
0083         return err;
0084
0085     crypto_cipher_clear_flags(tctx->essiv_cipher, CRYPTO_TFM_REQ_MASK);
0086     crypto_cipher_set_flags(tctx->essiv_cipher,
0087                 crypto_skcipher_get_flags(tfm) &
0088                 CRYPTO_TFM_REQ_MASK);
0089     return crypto_cipher_setkey(tctx->essiv_cipher, salt,
0090                     crypto_shash_digestsize(tctx->hash));
0091 }
0092
0093 static int essiv_aead_setkey(struct crypto_aead *tfm, const u8 *key,
0094                  unsigned int keylen)
0095 {
0096     struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
0097     SHASH_DESC_ON_STACK(desc, tctx->hash);
0098     struct crypto_authenc_keys keys;
0099     u8 salt[HASH_MAX_DIGESTSIZE];
0100     int err;
0101
0102     crypto_aead_clear_flags(tctx->u.aead, CRYPTO_TFM_REQ_MASK);
0103     crypto_aead_set_flags(tctx->u.aead, crypto_aead_get_flags(tfm) &
0104                         CRYPTO_TFM_REQ_MASK);
0105     err = crypto_aead_setkey(tctx->u.aead, key, keylen);
0106     if (err)
0107         return err;
0108
0109     if (crypto_authenc_extractkeys(&keys, key, keylen) != 0)
0110         return -EINVAL;
0111
0112     desc->tfm = tctx->hash;
0113     err = crypto_shash_init(desc) ?:
0114           crypto_shash_update(desc, keys.enckey, keys.enckeylen) ?:
0115           crypto_shash_finup(desc, keys.authkey, keys.authkeylen, salt);
0116     if (err)
0117         return err;
0118
0119     crypto_cipher_clear_flags(tctx->essiv_cipher, CRYPTO_TFM_REQ_MASK);
0120     crypto_cipher_set_flags(tctx->essiv_cipher, crypto_aead_get_flags(tfm) &
0121                             CRYPTO_TFM_REQ_MASK);
0122     return crypto_cipher_setkey(tctx->essiv_cipher, salt,
0123                     crypto_shash_digestsize(tctx->hash));
0124 }
0125
0126 static int essiv_aead_setauthsize(struct crypto_aead *tfm,
0127                   unsigned int authsize)
0128 {
0129     struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
0130
0131     return crypto_aead_setauthsize(tctx->u.aead, authsize);
0132 }
0133
0134 static void essiv_skcipher_done(struct crypto_async_request *areq, int err)
0135 {
0136     struct skcipher_request *req = areq->data;
0137
0138     skcipher_request_complete(req, err);
0139 }
0140
0141 static int essiv_skcipher_crypt(struct skcipher_request *req, bool enc)
0142 {
0143     struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
0144     const struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
0145     struct skcipher_request *subreq = skcipher_request_ctx(req);
0146
0147     crypto_cipher_encrypt_one(tctx->essiv_cipher, req->iv, req->iv);
0148
0149     skcipher_request_set_tfm(subreq, tctx->u.skcipher);
0150     skcipher_request_set_crypt(subreq, req->src, req->dst, req->cryptlen,
0151                    req->iv);
0152     skcipher_request_set_callback(subreq, skcipher_request_flags(req),
0153                       essiv_skcipher_done, req);
0154
0155     return enc ? crypto_skcipher_encrypt(subreq) :
0156              crypto_skcipher_decrypt(subreq);
0157 }
0158
0159 static int essiv_skcipher_encrypt(struct skcipher_request *req)
0160 {
0161     return essiv_skcipher_crypt(req, true);
0162 }
0163
0164 static int essiv_skcipher_decrypt(struct skcipher_request *req)
0165 {
0166     return essiv_skcipher_crypt(req, false);
0167 }
0168
0169 static void essiv_aead_done(struct crypto_async_request *areq, int err)
0170 {
0171     struct aead_request *req = areq->data;
0172     struct essiv_aead_request_ctx *rctx = aead_request_ctx(req);
0173
0174     kfree(rctx->assoc);
0175     aead_request_complete(req, err);
0176 }
0177
0178 static int essiv_aead_crypt(struct aead_request *req, bool enc)
0179 {
0180     struct crypto_aead *tfm = crypto_aead_reqtfm(req);
0181     const struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
0182     struct essiv_aead_request_ctx *rctx = aead_request_ctx(req);
0183     struct aead_request *subreq = &rctx->aead_req;
0184     struct scatterlist *src = req->src;
0185     int err;
0186
0187     crypto_cipher_encrypt_one(tctx->essiv_cipher, req->iv, req->iv);
0188
0189     /*
0190      * dm-crypt embeds the sector number and the IV in the AAD region, so
0191      * we have to copy the converted IV into the right scatterlist before
0192      * we pass it on.
0193      */
0194     rctx->assoc = NULL;
0195     if (req->src == req->dst || !enc) {
0196         scatterwalk_map_and_copy(req->iv, req->dst,
0197                      req->assoclen - crypto_aead_ivsize(tfm),
0198                      crypto_aead_ivsize(tfm), 1);
0199     } else {
0200         u8 *iv = (u8 *)aead_request_ctx(req) + tctx->ivoffset;
0201         int ivsize = crypto_aead_ivsize(tfm);
0202         int ssize = req->assoclen - ivsize;
0203         struct scatterlist *sg;
0204         int nents;
0205
0206         if (ssize < 0)
0207             return -EINVAL;
0208
0209         nents = sg_nents_for_len(req->src, ssize);
0210         if (nents < 0)
0211             return -EINVAL;
0212
0213         memcpy(iv, req->iv, ivsize);
0214         sg_init_table(rctx->sg, 4);
0215
0216         if (unlikely(nents > 1)) {
0217             /*
0218              * This is a case that rarely occurs in practice, but
0219              * for correctness, we have to deal with it nonetheless.
0220              */
0221             rctx->assoc = kmalloc(ssize, GFP_ATOMIC);
0222             if (!rctx->assoc)
0223                 return -ENOMEM;
0224
0225             scatterwalk_map_and_copy(rctx->assoc, req->src, 0,
0226                          ssize, 0);
0227             sg_set_buf(rctx->sg, rctx->assoc, ssize);
0228         } else {
0229             sg_set_page(rctx->sg, sg_page(req->src), ssize,
0230                     req->src->offset);
0231         }
0232
0233         sg_set_buf(rctx->sg + 1, iv, ivsize);
0234         sg = scatterwalk_ffwd(rctx->sg + 2, req->src, req->assoclen);
0235         if (sg != rctx->sg + 2)
0236             sg_chain(rctx->sg, 3, sg);
0237
0238         src = rctx->sg;
0239     }
0240
0241     aead_request_set_tfm(subreq, tctx->u.aead);
0242     aead_request_set_ad(subreq, req->assoclen);
0243     aead_request_set_callback(subreq, aead_request_flags(req),
0244                   essiv_aead_done, req);
0245     aead_request_set_crypt(subreq, src, req->dst, req->cryptlen, req->iv);
0246
0247     err = enc ? crypto_aead_encrypt(subreq) :
0248             crypto_aead_decrypt(subreq);
0249
0250     if (rctx->assoc && err != -EINPROGRESS)
0251         kfree(rctx->assoc);
0252     return err;
0253 }
0254
0255 static int essiv_aead_encrypt(struct aead_request *req)
0256 {
0257     return essiv_aead_crypt(req, true);
0258 }
0259
0260 static int essiv_aead_decrypt(struct aead_request *req)
0261 {
0262     return essiv_aead_crypt(req, false);
0263 }
0264
0265 static int essiv_init_tfm(struct essiv_instance_ctx *ictx,
0266               struct essiv_tfm_ctx *tctx)
0267 {
0268     struct crypto_cipher *essiv_cipher;
0269     struct crypto_shash *hash;
0270     int err;
0271
0272     essiv_cipher = crypto_alloc_cipher(ictx->essiv_cipher_name, 0, 0);
0273     if (IS_ERR(essiv_cipher))
0274         return PTR_ERR(essiv_cipher);
0275
0276     hash = crypto_alloc_shash(ictx->shash_driver_name, 0, 0);
0277     if (IS_ERR(hash)) {
0278         err = PTR_ERR(hash);
0279         goto err_free_essiv_cipher;
0280     }
0281
0282     tctx->essiv_cipher = essiv_cipher;
0283     tctx->hash = hash;
0284
0285     return 0;
0286
0287 err_free_essiv_cipher:
0288     crypto_free_cipher(essiv_cipher);
0289     return err;
0290 }
0291
0292 static int essiv_skcipher_init_tfm(struct crypto_skcipher *tfm)
0293 {
0294     struct skcipher_instance *inst = skcipher_alg_instance(tfm);
0295     struct essiv_instance_ctx *ictx = skcipher_instance_ctx(inst);
0296     struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
0297     struct crypto_skcipher *skcipher;
0298     int err;
0299
0300     skcipher = crypto_spawn_skcipher(&ictx->u.skcipher_spawn);
0301     if (IS_ERR(skcipher))
0302         return PTR_ERR(skcipher);
0303
0304     crypto_skcipher_set_reqsize(tfm, sizeof(struct skcipher_request) +
0305                          crypto_skcipher_reqsize(skcipher));
0306
0307     err = essiv_init_tfm(ictx, tctx);
0308     if (err) {
0309         crypto_free_skcipher(skcipher);
0310         return err;
0311     }
0312
0313     tctx->u.skcipher = skcipher;
0314     return 0;
0315 }
0316
0317 static int essiv_aead_init_tfm(struct crypto_aead *tfm)
0318 {
0319     struct aead_instance *inst = aead_alg_instance(tfm);
0320     struct essiv_instance_ctx *ictx = aead_instance_ctx(inst);
0321     struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
0322     struct crypto_aead *aead;
0323     unsigned int subreq_size;
0324     int err;
0325
0326     BUILD_BUG_ON(offsetofend(struct essiv_aead_request_ctx, aead_req) !=
0327              sizeof(struct essiv_aead_request_ctx));
0328
0329     aead = crypto_spawn_aead(&ictx->u.aead_spawn);
0330     if (IS_ERR(aead))
0331         return PTR_ERR(aead);
0332
0333     subreq_size = sizeof_field(struct essiv_aead_request_ctx, aead_req) +
0334               crypto_aead_reqsize(aead);
0335
0336     tctx->ivoffset = offsetof(struct essiv_aead_request_ctx, aead_req) +
0337              subreq_size;
0338     crypto_aead_set_reqsize(tfm, tctx->ivoffset + crypto_aead_ivsize(aead));
0339
0340     err = essiv_init_tfm(ictx, tctx);
0341     if (err) {
0342         crypto_free_aead(aead);
0343         return err;
0344     }
0345
0346     tctx->u.aead = aead;
0347     return 0;
0348 }
0349
0350 static void essiv_skcipher_exit_tfm(struct crypto_skcipher *tfm)
0351 {
0352     struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
0353
0354     crypto_free_skcipher(tctx->u.skcipher);
0355     crypto_free_cipher(tctx->essiv_cipher);
0356     crypto_free_shash(tctx->hash);
0357 }
0358
0359 static void essiv_aead_exit_tfm(struct crypto_aead *tfm)
0360 {
0361     struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
0362
0363     crypto_free_aead(tctx->u.aead);
0364     crypto_free_cipher(tctx->essiv_cipher);
0365     crypto_free_shash(tctx->hash);
0366 }
0367
0368 static void essiv_skcipher_free_instance(struct skcipher_instance *inst)
0369 {
0370     struct essiv_instance_ctx *ictx = skcipher_instance_ctx(inst);
0371
0372     crypto_drop_skcipher(&ictx->u.skcipher_spawn);
0373     kfree(inst);
0374 }
0375
0376 static void essiv_aead_free_instance(struct aead_instance *inst)
0377 {
0378     struct essiv_instance_ctx *ictx = aead_instance_ctx(inst);
0379
0380     crypto_drop_aead(&ictx->u.aead_spawn);
0381     kfree(inst);
0382 }
0383
0384 static bool parse_cipher_name(char *essiv_cipher_name, const char *cra_name)
0385 {
0386     const char *p, *q;
0387     int len;
0388
0389     /* find the last opening parens */
0390     p = strrchr(cra_name, '(');
0391     if (!p++)
0392         return false;
0393
0394     /* find the first closing parens in the tail of the string */
0395     q = strchr(p, ')');
0396     if (!q)
0397         return false;
0398
0399     len = q - p;
0400     if (len >= CRYPTO_MAX_ALG_NAME)
0401         return false;
0402
0403     memcpy(essiv_cipher_name, p, len);
0404     essiv_cipher_name[len] = '\0';
0405     return true;
0406 }
0407
0408 static bool essiv_supported_algorithms(const char *essiv_cipher_name,
0409                        struct shash_alg *hash_alg,
0410                        int ivsize)
0411 {
0412     struct crypto_alg *alg;
0413     bool ret = false;
0414
0415     alg = crypto_alg_mod_lookup(essiv_cipher_name,
0416                     CRYPTO_ALG_TYPE_CIPHER,
0417                     CRYPTO_ALG_TYPE_MASK);
0418     if (IS_ERR(alg))
0419         return false;
0420
0421     if (hash_alg->digestsize < alg->cra_cipher.cia_min_keysize ||
0422         hash_alg->digestsize > alg->cra_cipher.cia_max_keysize)
0423         goto out;
0424
0425     if (ivsize != alg->cra_blocksize)
0426         goto out;
0427
0428     if (crypto_shash_alg_needs_key(hash_alg))
0429         goto out;
0430
0431     ret = true;
0432
0433 out:
0434     crypto_mod_put(alg);
0435     return ret;
0436 }
0437
0438 static int essiv_create(struct crypto_template *tmpl, struct rtattr **tb)
0439 {
0440     struct crypto_attr_type *algt;
0441     const char *inner_cipher_name;
0442     const char *shash_name;
0443     struct skcipher_instance *skcipher_inst = NULL;
0444     struct aead_instance *aead_inst = NULL;
0445     struct crypto_instance *inst;
0446     struct crypto_alg *base, *block_base;
0447     struct essiv_instance_ctx *ictx;
0448     struct skcipher_alg *skcipher_alg = NULL;
0449     struct aead_alg *aead_alg = NULL;
0450     struct crypto_alg *_hash_alg;
0451     struct shash_alg *hash_alg;
0452     int ivsize;
0453     u32 type;
0454     u32 mask;
0455     int err;
0456
0457     algt = crypto_get_attr_type(tb);
0458     if (IS_ERR(algt))
0459         return PTR_ERR(algt);
0460
0461     inner_cipher_name = crypto_attr_alg_name(tb[1]);
0462     if (IS_ERR(inner_cipher_name))
0463         return PTR_ERR(inner_cipher_name);
0464
0465     shash_name = crypto_attr_alg_name(tb[2]);
0466     if (IS_ERR(shash_name))
0467         return PTR_ERR(shash_name);
0468
0469     type = algt->type & algt->mask;
0470     mask = crypto_algt_inherited_mask(algt);
0471
0472     switch (type) {
0473     case CRYPTO_ALG_TYPE_SKCIPHER:
0474         skcipher_inst = kzalloc(sizeof(*skcipher_inst) +
0475                     sizeof(*ictx), GFP_KERNEL);
0476         if (!skcipher_inst)
0477             return -ENOMEM;
0478         inst = skcipher_crypto_instance(skcipher_inst);
0479         base = &skcipher_inst->alg.base;
0480         ictx = crypto_instance_ctx(inst);
0481
0482         /* Symmetric cipher, e.g., "cbc(aes)" */
0483         err = crypto_grab_skcipher(&ictx->u.skcipher_spawn, inst,
0484                        inner_cipher_name, 0, mask);
0485         if (err)
0486             goto out_free_inst;
0487         skcipher_alg = crypto_spawn_skcipher_alg(&ictx->u.skcipher_spawn);
0488         block_base = &skcipher_alg->base;
0489         ivsize = crypto_skcipher_alg_ivsize(skcipher_alg);
0490         break;
0491
0492     case CRYPTO_ALG_TYPE_AEAD:
0493         aead_inst = kzalloc(sizeof(*aead_inst) +
0494                     sizeof(*ictx), GFP_KERNEL);
0495         if (!aead_inst)
0496             return -ENOMEM;
0497         inst = aead_crypto_instance(aead_inst);
0498         base = &aead_inst->alg.base;
0499         ictx = crypto_instance_ctx(inst);
0500
0501         /* AEAD cipher, e.g., "authenc(hmac(sha256),cbc(aes))" */
0502         err = crypto_grab_aead(&ictx->u.aead_spawn, inst,
0503                        inner_cipher_name, 0, mask);
0504         if (err)
0505             goto out_free_inst;
0506         aead_alg = crypto_spawn_aead_alg(&ictx->u.aead_spawn);
0507         block_base = &aead_alg->base;
0508         if (!strstarts(block_base->cra_name, "authenc(")) {
0509             pr_warn("Only authenc() type AEADs are supported by ESSIV\n");
0510             err = -EINVAL;
0511             goto out_drop_skcipher;
0512         }
0513         ivsize = aead_alg->ivsize;
0514         break;
0515
0516     default:
0517         return -EINVAL;
0518     }
0519
0520     if (!parse_cipher_name(ictx->essiv_cipher_name, block_base->cra_name)) {
0521         pr_warn("Failed to parse ESSIV cipher name from skcipher cra_name\n");
0522         err = -EINVAL;
0523         goto out_drop_skcipher;
0524     }
0525
0526     /* Synchronous hash, e.g., "sha256" */
0527     _hash_alg = crypto_alg_mod_lookup(shash_name,
0528                       CRYPTO_ALG_TYPE_SHASH,
0529                       CRYPTO_ALG_TYPE_MASK | mask);
0530     if (IS_ERR(_hash_alg)) {
0531         err = PTR_ERR(_hash_alg);
0532         goto out_drop_skcipher;
0533     }
0534     hash_alg = __crypto_shash_alg(_hash_alg);
0535
0536     /* Check the set of algorithms */
0537     if (!essiv_supported_algorithms(ictx->essiv_cipher_name, hash_alg,
0538                     ivsize)) {
0539         pr_warn("Unsupported essiv instantiation: essiv(%s,%s)\n",
0540             block_base->cra_name, hash_alg->base.cra_name);
0541         err = -EINVAL;
0542         goto out_free_hash;
0543     }
0544
0545     /* record the driver name so we can instantiate this exact algo later */
0546     strlcpy(ictx->shash_driver_name, hash_alg->base.cra_driver_name,
0547         CRYPTO_MAX_ALG_NAME);
0548
0549     /* Instance fields */
0550
0551     err = -ENAMETOOLONG;
0552     if (snprintf(base->cra_name, CRYPTO_MAX_ALG_NAME,
0553              "essiv(%s,%s)", block_base->cra_name,
0554              hash_alg->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
0555         goto out_free_hash;
0556     if (snprintf(base->cra_driver_name, CRYPTO_MAX_ALG_NAME,
0557              "essiv(%s,%s)", block_base->cra_driver_name,
0558              hash_alg->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
0559         goto out_free_hash;
0560
0561     /*
0562      * hash_alg wasn't gotten via crypto_grab*(), so we need to inherit its
0563      * flags manually.
0564      */
0565     base->cra_flags        |= (hash_alg->base.cra_flags &
0566                    CRYPTO_ALG_INHERITED_FLAGS);
0567     base->cra_blocksize = block_base->cra_blocksize;
0568     base->cra_ctxsize   = sizeof(struct essiv_tfm_ctx);
0569     base->cra_alignmask = block_base->cra_alignmask;
0570     base->cra_priority  = block_base->cra_priority;
0571
0572     if (type == CRYPTO_ALG_TYPE_SKCIPHER) {
0573         skcipher_inst->alg.setkey   = essiv_skcipher_setkey;
0574         skcipher_inst->alg.encrypt  = essiv_skcipher_encrypt;
0575         skcipher_inst->alg.decrypt  = essiv_skcipher_decrypt;
0576         skcipher_inst->alg.init     = essiv_skcipher_init_tfm;
0577         skcipher_inst->alg.exit     = essiv_skcipher_exit_tfm;
0578
0579         skcipher_inst->alg.min_keysize  = crypto_skcipher_alg_min_keysize(skcipher_alg);
0580         skcipher_inst->alg.max_keysize  = crypto_skcipher_alg_max_keysize(skcipher_alg);
0581         skcipher_inst->alg.ivsize   = ivsize;
0582         skcipher_inst->alg.chunksize    = crypto_skcipher_alg_chunksize(skcipher_alg);
0583         skcipher_inst->alg.walksize = crypto_skcipher_alg_walksize(skcipher_alg);
0584
0585         skcipher_inst->free     = essiv_skcipher_free_instance;
0586
0587         err = skcipher_register_instance(tmpl, skcipher_inst);
0588     } else {
0589         aead_inst->alg.setkey       = essiv_aead_setkey;
0590         aead_inst->alg.setauthsize  = essiv_aead_setauthsize;
0591         aead_inst->alg.encrypt      = essiv_aead_encrypt;
0592         aead_inst->alg.decrypt      = essiv_aead_decrypt;
0593         aead_inst->alg.init     = essiv_aead_init_tfm;
0594         aead_inst->alg.exit     = essiv_aead_exit_tfm;
0595
0596         aead_inst->alg.ivsize       = ivsize;
0597         aead_inst->alg.maxauthsize  = crypto_aead_alg_maxauthsize(aead_alg);
0598         aead_inst->alg.chunksize    = crypto_aead_alg_chunksize(aead_alg);
0599
0600         aead_inst->free         = essiv_aead_free_instance;
0601
0602         err = aead_register_instance(tmpl, aead_inst);
0603     }
0604
0605     if (err)
0606         goto out_free_hash;
0607
0608     crypto_mod_put(_hash_alg);
0609     return 0;
0610
0611 out_free_hash:
0612     crypto_mod_put(_hash_alg);
0613 out_drop_skcipher:
0614     if (type == CRYPTO_ALG_TYPE_SKCIPHER)
0615         crypto_drop_skcipher(&ictx->u.skcipher_spawn);
0616     else
0617         crypto_drop_aead(&ictx->u.aead_spawn);
0618 out_free_inst:
0619     kfree(skcipher_inst);
0620     kfree(aead_inst);
0621     return err;
0622 }
0623
0624 /* essiv(cipher_name, shash_name) */
0625 static struct crypto_template essiv_tmpl = {
0626     .name   = "essiv",
0627     .create = essiv_create,
0628     .module = THIS_MODULE,
0629 };
0630
0631 static int __init essiv_module_init(void)
0632 {
0633     return crypto_register_template(&essiv_tmpl);
0634 }
0635
0636 static void __exit essiv_module_exit(void)
0637 {
0638     crypto_unregister_template(&essiv_tmpl);
0639 }
0640
0641 subsys_initcall(essiv_module_init);
0642 module_exit(essiv_module_exit);
0643
0644 MODULE_DESCRIPTION("ESSIV skcipher/aead wrapper for block encryption");
0645 MODULE_LICENSE("GPL v2");
0646 MODULE_ALIAS_CRYPTO("essiv");
0647 MODULE_IMPORT_NS(CRYPTO_INTERNAL);