[linux.git] / crypto / essiv.c

// SPDX-License-Identifier: GPL-2.0
/*
 * ESSIV skcipher and aead template for block encryption
 *
 * This template encapsulates the ESSIV IV generation algorithm used by
 * dm-crypt and fscrypt, which converts the initial vector for the skcipher
 * used for block encryption, by encrypting it using the hash of the
 * skcipher key as encryption key. Usually, the input IV is a 64-bit sector
 * number in LE representation zero-padded to the size of the IV, but this
 * is not assumed by this driver.
 *
 * The typical use of this template is to instantiate the skcipher
 * 'essiv(cbc(aes),sha256)', which is the only instantiation used by
 * fscrypt, and the most relevant one for dm-crypt. However, dm-crypt
 * also permits ESSIV to be used in combination with the authenc template,
 * e.g., 'essiv(authenc(hmac(sha256),cbc(aes)),sha256)', in which case
 * we need to instantiate an aead that accepts the same special key format
 * as the authenc template, and deals with the way the encrypted IV is
 * embedded into the AAD area of the aead request. This means the AEAD
 * flavor produced by this template is tightly coupled to the way dm-crypt
 * happens to use it.
 *
 * Copyright (c) 2019 Linaro, Ltd. <[email protected]>
 *
 * Heavily based on:
 * adiantum length-preserving encryption mode
 *
 * Copyright 2018 Google LLC
 */

#include <crypto/authenc.h>
#include <crypto/internal/aead.h>
#include <crypto/internal/cipher.h>
#include <crypto/internal/hash.h>
#include <crypto/internal/skcipher.h>
#include <crypto/scatterwalk.h>
#include <linux/module.h>

#include "internal.h"

struct essiv_instance_ctx {
	union {
		struct crypto_skcipher_spawn	skcipher_spawn;
		struct crypto_aead_spawn	aead_spawn;
	} u;
	char	essiv_cipher_name[CRYPTO_MAX_ALG_NAME];
	char	shash_driver_name[CRYPTO_MAX_ALG_NAME];
};

struct essiv_tfm_ctx {
	union {
		struct crypto_skcipher	*skcipher;
		struct crypto_aead	*aead;
	} u;
	struct crypto_cipher		*essiv_cipher;
	struct crypto_shash		*hash;
	int				ivoffset;
};

struct essiv_aead_request_ctx {
	struct scatterlist		sg[4];
	u8				*assoc;
	struct aead_request		aead_req;
};

static int essiv_skcipher_setkey(struct crypto_skcipher *tfm,
				 const u8 *key, unsigned int keylen)
{
	struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
	u8 salt[HASH_MAX_DIGESTSIZE];
	int err;

	crypto_skcipher_clear_flags(tctx->u.skcipher, CRYPTO_TFM_REQ_MASK);
	crypto_skcipher_set_flags(tctx->u.skcipher,
				  crypto_skcipher_get_flags(tfm) &
				  CRYPTO_TFM_REQ_MASK);
	err = crypto_skcipher_setkey(tctx->u.skcipher, key, keylen);
	if (err)
		return err;

	err = crypto_shash_tfm_digest(tctx->hash, key, keylen, salt);
	if (err)
		return err;

	crypto_cipher_clear_flags(tctx->essiv_cipher, CRYPTO_TFM_REQ_MASK);
	crypto_cipher_set_flags(tctx->essiv_cipher,
				crypto_skcipher_get_flags(tfm) &
				CRYPTO_TFM_REQ_MASK);
	return crypto_cipher_setkey(tctx->essiv_cipher, salt,
				    crypto_shash_digestsize(tctx->hash));
}

static int essiv_aead_setkey(struct crypto_aead *tfm, const u8 *key,
			     unsigned int keylen)
{
	struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
	SHASH_DESC_ON_STACK(desc, tctx->hash);
	struct crypto_authenc_keys keys;
	u8 salt[HASH_MAX_DIGESTSIZE];
	int err;

	crypto_aead_clear_flags(tctx->u.aead, CRYPTO_TFM_REQ_MASK);
	crypto_aead_set_flags(tctx->u.aead, crypto_aead_get_flags(tfm) &
					    CRYPTO_TFM_REQ_MASK);
	err = crypto_aead_setkey(tctx->u.aead, key, keylen);
	if (err)
		return err;

	if (crypto_authenc_extractkeys(&keys, key, keylen) != 0)
		return -EINVAL;

	desc->tfm = tctx->hash;
	err = crypto_shash_init(desc) ?:
	      crypto_shash_update(desc, keys.enckey, keys.enckeylen) ?:
	      crypto_shash_finup(desc, keys.authkey, keys.authkeylen, salt);
	if (err)
		return err;

	crypto_cipher_clear_flags(tctx->essiv_cipher, CRYPTO_TFM_REQ_MASK);
	crypto_cipher_set_flags(tctx->essiv_cipher, crypto_aead_get_flags(tfm) &
						    CRYPTO_TFM_REQ_MASK);
	return crypto_cipher_setkey(tctx->essiv_cipher, salt,
				    crypto_shash_digestsize(tctx->hash));
}

static int essiv_aead_setauthsize(struct crypto_aead *tfm,
				  unsigned int authsize)
{
	struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);

	return crypto_aead_setauthsize(tctx->u.aead, authsize);
}

static void essiv_skcipher_done(void *data, int err)
{
	struct skcipher_request *req = data;

	skcipher_request_complete(req, err);
}

static int essiv_skcipher_crypt(struct skcipher_request *req, bool enc)
{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	const struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
	struct skcipher_request *subreq = skcipher_request_ctx(req);

	crypto_cipher_encrypt_one(tctx->essiv_cipher, req->iv, req->iv);

	skcipher_request_set_tfm(subreq, tctx->u.skcipher);
	skcipher_request_set_crypt(subreq, req->src, req->dst, req->cryptlen,
				   req->iv);
	skcipher_request_set_callback(subreq, skcipher_request_flags(req),
				      essiv_skcipher_done, req);

	return enc ? crypto_skcipher_encrypt(subreq) :
		     crypto_skcipher_decrypt(subreq);
}

static int essiv_skcipher_encrypt(struct skcipher_request *req)
{
	return essiv_skcipher_crypt(req, true);
}

static int essiv_skcipher_decrypt(struct skcipher_request *req)
{
	return essiv_skcipher_crypt(req, false);
}

static void essiv_aead_done(void *data, int err)
{
	struct aead_request *req = data;
	struct essiv_aead_request_ctx *rctx = aead_request_ctx(req);

	if (err == -EINPROGRESS)
		goto out;

	kfree(rctx->assoc);

out:
	aead_request_complete(req, err);
}

static int essiv_aead_crypt(struct aead_request *req, bool enc)
{
	struct crypto_aead *tfm = crypto_aead_reqtfm(req);
	const struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
	struct essiv_aead_request_ctx *rctx = aead_request_ctx(req);
	struct aead_request *subreq = &rctx->aead_req;
	struct scatterlist *src = req->src;
	int err;

	crypto_cipher_encrypt_one(tctx->essiv_cipher, req->iv, req->iv);

	/*
	 * dm-crypt embeds the sector number and the IV in the AAD region, so
	 * we have to copy the converted IV into the right scatterlist before
	 * we pass it on.
	 */
	rctx->assoc = NULL;
	if (req->src == req->dst || !enc) {
		scatterwalk_map_and_copy(req->iv, req->dst,
					 req->assoclen - crypto_aead_ivsize(tfm),
					 crypto_aead_ivsize(tfm), 1);
	} else {
		u8 *iv = (u8 *)aead_request_ctx(req) + tctx->ivoffset;
		int ivsize = crypto_aead_ivsize(tfm);
		int ssize = req->assoclen - ivsize;
		struct scatterlist *sg;
		int nents;

		if (ssize < 0)
			return -EINVAL;

		nents = sg_nents_for_len(req->src, ssize);
		if (nents < 0)
			return -EINVAL;

		memcpy(iv, req->iv, ivsize);
		sg_init_table(rctx->sg, 4);

		if (unlikely(nents > 1)) {
			/*
			 * This is a case that rarely occurs in practice, but
			 * for correctness, we have to deal with it nonetheless.
			 */
			rctx->assoc = kmalloc(ssize, GFP_ATOMIC);
			if (!rctx->assoc)
				return -ENOMEM;

			scatterwalk_map_and_copy(rctx->assoc, req->src, 0,
						 ssize, 0);
			sg_set_buf(rctx->sg, rctx->assoc, ssize);
		} else {
			sg_set_page(rctx->sg, sg_page(req->src), ssize,
				    req->src->offset);
		}

		sg_set_buf(rctx->sg + 1, iv, ivsize);
		sg = scatterwalk_ffwd(rctx->sg + 2, req->src, req->assoclen);
		if (sg != rctx->sg + 2)
			sg_chain(rctx->sg, 3, sg);

		src = rctx->sg;
	}

	aead_request_set_tfm(subreq, tctx->u.aead);
	aead_request_set_ad(subreq, req->assoclen);
	aead_request_set_callback(subreq, aead_request_flags(req),
				  essiv_aead_done, req);
	aead_request_set_crypt(subreq, src, req->dst, req->cryptlen, req->iv);

	err = enc ? crypto_aead_encrypt(subreq) :
		    crypto_aead_decrypt(subreq);

	if (rctx->assoc && err != -EINPROGRESS && err != -EBUSY)
		kfree(rctx->assoc);
	return err;
}

static int essiv_aead_encrypt(struct aead_request *req)
{
	return essiv_aead_crypt(req, true);
}

static int essiv_aead_decrypt(struct aead_request *req)
{
	return essiv_aead_crypt(req, false);
}

static int essiv_init_tfm(struct essiv_instance_ctx *ictx,
			  struct essiv_tfm_ctx *tctx)
{
	struct crypto_cipher *essiv_cipher;
	struct crypto_shash *hash;
	int err;

	essiv_cipher = crypto_alloc_cipher(ictx->essiv_cipher_name, 0, 0);
	if (IS_ERR(essiv_cipher))
		return PTR_ERR(essiv_cipher);

	hash = crypto_alloc_shash(ictx->shash_driver_name, 0, 0);
	if (IS_ERR(hash)) {
		err = PTR_ERR(hash);
		goto err_free_essiv_cipher;
	}

	tctx->essiv_cipher = essiv_cipher;
	tctx->hash = hash;

	return 0;

err_free_essiv_cipher:
	crypto_free_cipher(essiv_cipher);
	return err;
}

static int essiv_skcipher_init_tfm(struct crypto_skcipher *tfm)
{
	struct skcipher_instance *inst = skcipher_alg_instance(tfm);
	struct essiv_instance_ctx *ictx = skcipher_instance_ctx(inst);
	struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
	struct crypto_skcipher *skcipher;
	int err;

	skcipher = crypto_spawn_skcipher(&ictx->u.skcipher_spawn);
	if (IS_ERR(skcipher))
		return PTR_ERR(skcipher);

	crypto_skcipher_set_reqsize(tfm, sizeof(struct skcipher_request) +
				         crypto_skcipher_reqsize(skcipher));

	err = essiv_init_tfm(ictx, tctx);
	if (err) {
		crypto_free_skcipher(skcipher);
		return err;
	}

	tctx->u.skcipher = skcipher;
	return 0;
}

static int essiv_aead_init_tfm(struct crypto_aead *tfm)
{
	struct aead_instance *inst = aead_alg_instance(tfm);
	struct essiv_instance_ctx *ictx = aead_instance_ctx(inst);
	struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
	struct crypto_aead *aead;
	unsigned int subreq_size;
	int err;

	BUILD_BUG_ON(offsetofend(struct essiv_aead_request_ctx, aead_req) !=
		     sizeof(struct essiv_aead_request_ctx));

	aead = crypto_spawn_aead(&ictx->u.aead_spawn);
	if (IS_ERR(aead))
		return PTR_ERR(aead);

	subreq_size = sizeof_field(struct essiv_aead_request_ctx, aead_req) +
		      crypto_aead_reqsize(aead);

	tctx->ivoffset = offsetof(struct essiv_aead_request_ctx, aead_req) +
			 subreq_size;
	crypto_aead_set_reqsize(tfm, tctx->ivoffset + crypto_aead_ivsize(aead));

	err = essiv_init_tfm(ictx, tctx);
	if (err) {
		crypto_free_aead(aead);
		return err;
	}

	tctx->u.aead = aead;
	return 0;
}

static void essiv_skcipher_exit_tfm(struct crypto_skcipher *tfm)
{
	struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);

	crypto_free_skcipher(tctx->u.skcipher);
	crypto_free_cipher(tctx->essiv_cipher);
	crypto_free_shash(tctx->hash);
}

static void essiv_aead_exit_tfm(struct crypto_aead *tfm)
{
	struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);

	crypto_free_aead(tctx->u.aead);
	crypto_free_cipher(tctx->essiv_cipher);
	crypto_free_shash(tctx->hash);
}

static void essiv_skcipher_free_instance(struct skcipher_instance *inst)
{
	struct essiv_instance_ctx *ictx = skcipher_instance_ctx(inst);

	crypto_drop_skcipher(&ictx->u.skcipher_spawn);
	kfree(inst);
}

static void essiv_aead_free_instance(struct aead_instance *inst)
{
	struct essiv_instance_ctx *ictx = aead_instance_ctx(inst);

	crypto_drop_aead(&ictx->u.aead_spawn);
	kfree(inst);
}

static bool parse_cipher_name(char *essiv_cipher_name, const char *cra_name)
{
	const char *p, *q;
	int len;

	/* find the last opening parens */
	p = strrchr(cra_name, '(');
	if (!p++)
		return false;

	/* find the first closing parens in the tail of the string */
	q = strchr(p, ')');
	if (!q)
		return false;

	len = q - p;
	if (len >= CRYPTO_MAX_ALG_NAME)
		return false;

	memcpy(essiv_cipher_name, p, len);
	essiv_cipher_name[len] = '\0';
	return true;
}

static bool essiv_supported_algorithms(const char *essiv_cipher_name,
				       struct shash_alg *hash_alg,
				       int ivsize)
{
	struct crypto_alg *alg;
	bool ret = false;

	alg = crypto_alg_mod_lookup(essiv_cipher_name,
				    CRYPTO_ALG_TYPE_CIPHER,
				    CRYPTO_ALG_TYPE_MASK);
	if (IS_ERR(alg))
		return false;

	if (hash_alg->digestsize < alg->cra_cipher.cia_min_keysize ||
	    hash_alg->digestsize > alg->cra_cipher.cia_max_keysize)
		goto out;

	if (ivsize != alg->cra_blocksize)
		goto out;

	if (crypto_shash_alg_needs_key(hash_alg))
		goto out;

	ret = true;

out:
	crypto_mod_put(alg);
	return ret;
}

static int essiv_create(struct crypto_template *tmpl, struct rtattr **tb)
{
	struct skcipher_alg_common *skcipher_alg = NULL;
	struct crypto_attr_type *algt;
	const char *inner_cipher_name;
	const char *shash_name;
	struct skcipher_instance *skcipher_inst = NULL;
	struct aead_instance *aead_inst = NULL;
	struct crypto_instance *inst;
	struct crypto_alg *base, *block_base;
	struct essiv_instance_ctx *ictx;
	struct aead_alg *aead_alg = NULL;
	struct crypto_alg *_hash_alg;
	struct shash_alg *hash_alg;
	int ivsize;
	u32 type;
	u32 mask;
	int err;

	algt = crypto_get_attr_type(tb);
	if (IS_ERR(algt))
		return PTR_ERR(algt);

	inner_cipher_name = crypto_attr_alg_name(tb[1]);
	if (IS_ERR(inner_cipher_name))
		return PTR_ERR(inner_cipher_name);

	shash_name = crypto_attr_alg_name(tb[2]);
	if (IS_ERR(shash_name))
		return PTR_ERR(shash_name);

	type = algt->type & algt->mask;
	mask = crypto_algt_inherited_mask(algt);

	switch (type) {
	case CRYPTO_ALG_TYPE_LSKCIPHER:
		skcipher_inst = kzalloc(sizeof(*skcipher_inst) +
					sizeof(*ictx), GFP_KERNEL);
		if (!skcipher_inst)
			return -ENOMEM;
		inst = skcipher_crypto_instance(skcipher_inst);
		base = &skcipher_inst->alg.base;
		ictx = crypto_instance_ctx(inst);

		/* Symmetric cipher, e.g., "cbc(aes)" */
		err = crypto_grab_skcipher(&ictx->u.skcipher_spawn, inst,
					   inner_cipher_name, 0, mask);
		if (err)
			goto out_free_inst;
		skcipher_alg = crypto_spawn_skcipher_alg_common(
			&ictx->u.skcipher_spawn);
		block_base = &skcipher_alg->base;
		ivsize = skcipher_alg->ivsize;
		break;

	case CRYPTO_ALG_TYPE_AEAD:
		aead_inst = kzalloc(sizeof(*aead_inst) +
				    sizeof(*ictx), GFP_KERNEL);
		if (!aead_inst)
			return -ENOMEM;
		inst = aead_crypto_instance(aead_inst);
		base = &aead_inst->alg.base;
		ictx = crypto_instance_ctx(inst);

		/* AEAD cipher, e.g., "authenc(hmac(sha256),cbc(aes))" */
		err = crypto_grab_aead(&ictx->u.aead_spawn, inst,
				       inner_cipher_name, 0, mask);
		if (err)
			goto out_free_inst;
		aead_alg = crypto_spawn_aead_alg(&ictx->u.aead_spawn);
		block_base = &aead_alg->base;
		if (!strstarts(block_base->cra_name, "authenc(")) {
			pr_warn("Only authenc() type AEADs are supported by ESSIV\n");
			err = -EINVAL;
			goto out_drop_skcipher;
		}
		ivsize = aead_alg->ivsize;
		break;

	default:
		return -EINVAL;
	}

	if (!parse_cipher_name(ictx->essiv_cipher_name, block_base->cra_name)) {
		pr_warn("Failed to parse ESSIV cipher name from skcipher cra_name\n");
		err = -EINVAL;
		goto out_drop_skcipher;
	}

	/* Synchronous hash, e.g., "sha256" */
	_hash_alg = crypto_alg_mod_lookup(shash_name,
					  CRYPTO_ALG_TYPE_SHASH,
					  CRYPTO_ALG_TYPE_MASK | mask);
	if (IS_ERR(_hash_alg)) {
		err = PTR_ERR(_hash_alg);
		goto out_drop_skcipher;
	}
	hash_alg = __crypto_shash_alg(_hash_alg);

	/* Check the set of algorithms */
	if (!essiv_supported_algorithms(ictx->essiv_cipher_name, hash_alg,
					ivsize)) {
		pr_warn("Unsupported essiv instantiation: essiv(%s,%s)\n",
			block_base->cra_name, hash_alg->base.cra_name);
		err = -EINVAL;
		goto out_free_hash;
	}

	/* record the driver name so we can instantiate this exact algo later */
	strscpy(ictx->shash_driver_name, hash_alg->base.cra_driver_name,
		CRYPTO_MAX_ALG_NAME);

	/* Instance fields */

	err = -ENAMETOOLONG;
	if (snprintf(base->cra_name, CRYPTO_MAX_ALG_NAME,
		     "essiv(%s,%s)", block_base->cra_name,
		     hash_alg->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
		goto out_free_hash;
	if (snprintf(base->cra_driver_name, CRYPTO_MAX_ALG_NAME,
		     "essiv(%s,%s)", block_base->cra_driver_name,
		     hash_alg->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
		goto out_free_hash;

	/*
	 * hash_alg wasn't gotten via crypto_grab*(), so we need to inherit its
	 * flags manually.
	 */
	base->cra_flags        |= (hash_alg->base.cra_flags &
				   CRYPTO_ALG_INHERITED_FLAGS);
	base->cra_blocksize	= block_base->cra_blocksize;
	base->cra_ctxsize	= sizeof(struct essiv_tfm_ctx);
	base->cra_alignmask	= block_base->cra_alignmask;
	base->cra_priority	= block_base->cra_priority;

	if (type == CRYPTO_ALG_TYPE_LSKCIPHER) {
		skcipher_inst->alg.setkey	= essiv_skcipher_setkey;
		skcipher_inst->alg.encrypt	= essiv_skcipher_encrypt;
		skcipher_inst->alg.decrypt	= essiv_skcipher_decrypt;
		skcipher_inst->alg.init		= essiv_skcipher_init_tfm;
		skcipher_inst->alg.exit		= essiv_skcipher_exit_tfm;

		skcipher_inst->alg.min_keysize	= skcipher_alg->min_keysize;
		skcipher_inst->alg.max_keysize	= skcipher_alg->max_keysize;
		skcipher_inst->alg.ivsize	= ivsize;
		skcipher_inst->alg.chunksize	= skcipher_alg->chunksize;

		skcipher_inst->free		= essiv_skcipher_free_instance;

		err = skcipher_register_instance(tmpl, skcipher_inst);
	} else {
		aead_inst->alg.setkey		= essiv_aead_setkey;
		aead_inst->alg.setauthsize	= essiv_aead_setauthsize;
		aead_inst->alg.encrypt		= essiv_aead_encrypt;
		aead_inst->alg.decrypt		= essiv_aead_decrypt;
		aead_inst->alg.init		= essiv_aead_init_tfm;
		aead_inst->alg.exit		= essiv_aead_exit_tfm;

		aead_inst->alg.ivsize		= ivsize;
		aead_inst->alg.maxauthsize	= crypto_aead_alg_maxauthsize(aead_alg);
		aead_inst->alg.chunksize	= crypto_aead_alg_chunksize(aead_alg);

		aead_inst->free			= essiv_aead_free_instance;

		err = aead_register_instance(tmpl, aead_inst);
	}

	if (err)
		goto out_free_hash;

	crypto_mod_put(_hash_alg);
	return 0;

out_free_hash:
	crypto_mod_put(_hash_alg);
out_drop_skcipher:
	if (type == CRYPTO_ALG_TYPE_LSKCIPHER)
		crypto_drop_skcipher(&ictx->u.skcipher_spawn);
	else
		crypto_drop_aead(&ictx->u.aead_spawn);
out_free_inst:
	kfree(skcipher_inst);
	kfree(aead_inst);
	return err;
}

/* essiv(cipher_name, shash_name) */
static struct crypto_template essiv_tmpl = {
	.name	= "essiv",
	.create	= essiv_create,
	.module	= THIS_MODULE,
};

static int __init essiv_module_init(void)
{
	return crypto_register_template(&essiv_tmpl);
}

static void __exit essiv_module_exit(void)
{
	crypto_unregister_template(&essiv_tmpl);
}

subsys_initcall(essiv_module_init);
module_exit(essiv_module_exit);

MODULE_DESCRIPTION("ESSIV skcipher/aead wrapper for block encryption");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS_CRYPTO("essiv");
MODULE_IMPORT_NS(CRYPTO_INTERNAL);
Commit	Line	Data
be1eb7f7 AB	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. <[email protected]>
	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>
0eb76ba2	33	#include <crypto/internal/cipher.h>
be1eb7f7 AB	34	#include <crypto/internal/hash.h>
	35	#include <crypto/internal/skcipher.h>
	36	#include <crypto/scatterwalk.h>
	37	#include <linux/module.h>
	38
	39	#include "internal.h"
	40
	41	struct essiv_instance_ctx {
	42	union {
	43	struct crypto_skcipher_spawn skcipher_spawn;
	44	struct crypto_aead_spawn aead_spawn;
	45	} u;
	46	char essiv_cipher_name[CRYPTO_MAX_ALG_NAME];
	47	char shash_driver_name[CRYPTO_MAX_ALG_NAME];
	48	};
	49
	50	struct essiv_tfm_ctx {
	51	union {
	52	struct crypto_skcipher *skcipher;
	53	struct crypto_aead *aead;
	54	} u;
	55	struct crypto_cipher *essiv_cipher;
	56	struct crypto_shash *hash;
	57	int ivoffset;
	58	};
	59
	60	struct essiv_aead_request_ctx {
	61	struct scatterlist sg[4];
	62	u8 *assoc;
	63	struct aead_request aead_req;
	64	};
	65
	66	static int essiv_skcipher_setkey(struct crypto_skcipher *tfm,
	67	const u8 *key, unsigned int keylen)
	68	{
	69	struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
be1eb7f7 AB	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);
be1eb7f7 AB	78	if (err)
	79	return err;
	80
1306664f	81	err = crypto_shash_tfm_digest(tctx->hash, key, keylen, salt);
be1eb7f7 AB	82	if (err)
	83	return err;
	84
	85	crypto_cipher_clear_flags(tctx->essiv_cipher, CRYPTO_TFM_REQ_MASK);
	86	crypto_cipher_set_flags(tctx->essiv_cipher,
	87	crypto_skcipher_get_flags(tfm) &
	88	CRYPTO_TFM_REQ_MASK);
af5034e8 EB	89	return crypto_cipher_setkey(tctx->essiv_cipher, salt,
af5034e8 EB	90	crypto_shash_digestsize(tctx->hash));
be1eb7f7 AB	91	}
	92
	93	static int essiv_aead_setkey(struct crypto_aead tfm, const u8 key,
	94	unsigned int keylen)
	95	{
	96	struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
	97	SHASH_DESC_ON_STACK(desc, tctx->hash);
	98	struct crypto_authenc_keys keys;
	99	u8 salt[HASH_MAX_DIGESTSIZE];
	100	int err;
	101
	102	crypto_aead_clear_flags(tctx->u.aead, CRYPTO_TFM_REQ_MASK);
	103	crypto_aead_set_flags(tctx->u.aead, crypto_aead_get_flags(tfm) &
	104	CRYPTO_TFM_REQ_MASK);
	105	err = crypto_aead_setkey(tctx->u.aead, key, keylen);
be1eb7f7 AB	106	if (err)
	107	return err;
	108
674f368a	109	if (crypto_authenc_extractkeys(&keys, key, keylen) != 0)
be1eb7f7	110	return -EINVAL;
be1eb7f7 AB	111
	112	desc->tfm = tctx->hash;
	113	err = crypto_shash_init(desc) ?:
	114	crypto_shash_update(desc, keys.enckey, keys.enckeylen) ?:
	115	crypto_shash_finup(desc, keys.authkey, keys.authkeylen, salt);
	116	if (err)
	117	return err;
	118
	119	crypto_cipher_clear_flags(tctx->essiv_cipher, CRYPTO_TFM_REQ_MASK);
	120	crypto_cipher_set_flags(tctx->essiv_cipher, crypto_aead_get_flags(tfm) &
	121	CRYPTO_TFM_REQ_MASK);
af5034e8 EB	122	return crypto_cipher_setkey(tctx->essiv_cipher, salt,
af5034e8 EB	123	crypto_shash_digestsize(tctx->hash));
be1eb7f7 AB	124	}
	125
	126	static int essiv_aead_setauthsize(struct crypto_aead *tfm,
	127	unsigned int authsize)
	128	{
	129	struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
	130
	131	return crypto_aead_setauthsize(tctx->u.aead, authsize);
	132	}
	133
255e48eb	134	static void essiv_skcipher_done(void *data, int err)
be1eb7f7	135	{
255e48eb	136	struct skcipher_request *req = data;
be1eb7f7 AB	137
	138	skcipher_request_complete(req, err);
	139	}
	140
	141	static int essiv_skcipher_crypt(struct skcipher_request *req, bool enc)
	142	{
	143	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	144	const struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
	145	struct skcipher_request *subreq = skcipher_request_ctx(req);
	146
	147	crypto_cipher_encrypt_one(tctx->essiv_cipher, req->iv, req->iv);
	148
	149	skcipher_request_set_tfm(subreq, tctx->u.skcipher);
	150	skcipher_request_set_crypt(subreq, req->src, req->dst, req->cryptlen,
	151	req->iv);
	152	skcipher_request_set_callback(subreq, skcipher_request_flags(req),
	153	essiv_skcipher_done, req);
	154
	155	return enc ? crypto_skcipher_encrypt(subreq) :
	156	crypto_skcipher_decrypt(subreq);
	157	}
	158
	159	static int essiv_skcipher_encrypt(struct skcipher_request *req)
	160	{
	161	return essiv_skcipher_crypt(req, true);
	162	}
	163
	164	static int essiv_skcipher_decrypt(struct skcipher_request *req)
	165	{
	166	return essiv_skcipher_crypt(req, false);
	167	}
	168
255e48eb	169	static void essiv_aead_done(void *data, int err)
be1eb7f7	170	{
255e48eb	171	struct aead_request *req = data;
be1eb7f7 AB	172	struct essiv_aead_request_ctx *rctx = aead_request_ctx(req);
be1eb7f7 AB	173
b5a772ad HX	174	if (err == -EINPROGRESS)
	175	goto out;
	176
e18036da	177	kfree(rctx->assoc);
b5a772ad HX	178
b5a772ad HX	179	out:
be1eb7f7 AB	180	aead_request_complete(req, err);
	181	}
	182
	183	static int essiv_aead_crypt(struct aead_request *req, bool enc)
	184	{
	185	struct crypto_aead *tfm = crypto_aead_reqtfm(req);
	186	const struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
	187	struct essiv_aead_request_ctx *rctx = aead_request_ctx(req);
	188	struct aead_request *subreq = &rctx->aead_req;
	189	struct scatterlist *src = req->src;
	190	int err;
	191
	192	crypto_cipher_encrypt_one(tctx->essiv_cipher, req->iv, req->iv);
	193
	194	/*
	195	* dm-crypt embeds the sector number and the IV in the AAD region, so
	196	* we have to copy the converted IV into the right scatterlist before
	197	* we pass it on.
	198	*/
	199	rctx->assoc = NULL;
	200	if (req->src == req->dst \|\| !enc) {
	201	scatterwalk_map_and_copy(req->iv, req->dst,
	202	req->assoclen - crypto_aead_ivsize(tfm),
	203	crypto_aead_ivsize(tfm), 1);
	204	} else {
	205	u8 iv = (u8 )aead_request_ctx(req) + tctx->ivoffset;
	206	int ivsize = crypto_aead_ivsize(tfm);
	207	int ssize = req->assoclen - ivsize;
	208	struct scatterlist *sg;
	209	int nents;
	210
	211	if (ssize < 0)
	212	return -EINVAL;
	213
	214	nents = sg_nents_for_len(req->src, ssize);
	215	if (nents < 0)
	216	return -EINVAL;
	217
	218	memcpy(iv, req->iv, ivsize);
	219	sg_init_table(rctx->sg, 4);
	220
	221	if (unlikely(nents > 1)) {
	222	/*
	223	* This is a case that rarely occurs in practice, but
	224	* for correctness, we have to deal with it nonetheless.
	225	*/
	226	rctx->assoc = kmalloc(ssize, GFP_ATOMIC);
	227	if (!rctx->assoc)
	228	return -ENOMEM;
	229
	230	scatterwalk_map_and_copy(rctx->assoc, req->src, 0,
	231	ssize, 0);
	232	sg_set_buf(rctx->sg, rctx->assoc, ssize);
	233	} else {
	234	sg_set_page(rctx->sg, sg_page(req->src), ssize,
	235	req->src->offset);
	236	}
	237
	238	sg_set_buf(rctx->sg + 1, iv, ivsize);
	239	sg = scatterwalk_ffwd(rctx->sg + 2, req->src, req->assoclen);
	240	if (sg != rctx->sg + 2)
	241	sg_chain(rctx->sg, 3, sg);
	242
	243	src = rctx->sg;
244	}
245
246	aead_request_set_tfm(subreq, tctx->u.aead);
247	aead_request_set_ad(subreq, req->assoclen);
248	aead_request_set_callback(subreq, aead_request_flags(req),
249	essiv_aead_done, req);
250	aead_request_set_crypt(subreq, src, req->dst, req->cryptlen, req->iv);
251
252	err = enc ? crypto_aead_encrypt(subreq) :
253	crypto_aead_decrypt(subreq);
254
b5a772ad	255	if (rctx->assoc && err != -EINPROGRESS && err != -EBUSY)
be1eb7f7 AB	256	kfree(rctx->assoc);
	257	return err;
	258	}
	259
	260	static int essiv_aead_encrypt(struct aead_request *req)
	261	{
	262	return essiv_aead_crypt(req, true);
	263	}
	264
	265	static int essiv_aead_decrypt(struct aead_request *req)
	266	{
	267	return essiv_aead_crypt(req, false);
	268	}
	269
	270	static int essiv_init_tfm(struct essiv_instance_ctx *ictx,
	271	struct essiv_tfm_ctx *tctx)
	272	{
	273	struct crypto_cipher *essiv_cipher;
	274	struct crypto_shash *hash;
	275	int err;
	276
	277	essiv_cipher = crypto_alloc_cipher(ictx->essiv_cipher_name, 0, 0);
	278	if (IS_ERR(essiv_cipher))
	279	return PTR_ERR(essiv_cipher);
	280
	281	hash = crypto_alloc_shash(ictx->shash_driver_name, 0, 0);
	282	if (IS_ERR(hash)) {
	283	err = PTR_ERR(hash);
	284	goto err_free_essiv_cipher;
	285	}
	286
	287	tctx->essiv_cipher = essiv_cipher;
	288	tctx->hash = hash;
	289
	290	return 0;
	291
	292	err_free_essiv_cipher:
	293	crypto_free_cipher(essiv_cipher);
	294	return err;
	295	}
	296
	297	static int essiv_skcipher_init_tfm(struct crypto_skcipher *tfm)
	298	{
	299	struct skcipher_instance *inst = skcipher_alg_instance(tfm);
	300	struct essiv_instance_ctx *ictx = skcipher_instance_ctx(inst);
	301	struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
	302	struct crypto_skcipher *skcipher;
	303	int err;
	304
	305	skcipher = crypto_spawn_skcipher(&ictx->u.skcipher_spawn);
	306	if (IS_ERR(skcipher))
	307	return PTR_ERR(skcipher);
	308
	309	crypto_skcipher_set_reqsize(tfm, sizeof(struct skcipher_request) +
	310	crypto_skcipher_reqsize(skcipher));
	311
	312	err = essiv_init_tfm(ictx, tctx);
	313	if (err) {
	314	crypto_free_skcipher(skcipher);
	315	return err;
	316	}
	317
	318	tctx->u.skcipher = skcipher;
	319	return 0;
320	}
321
322	static int essiv_aead_init_tfm(struct crypto_aead *tfm)
323	{
324	struct aead_instance *inst = aead_alg_instance(tfm);
325	struct essiv_instance_ctx *ictx = aead_instance_ctx(inst);
326	struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
327	struct crypto_aead *aead;
328	unsigned int subreq_size;
329	int err;
330
331	BUILD_BUG_ON(offsetofend(struct essiv_aead_request_ctx, aead_req) !=
332	sizeof(struct essiv_aead_request_ctx));
333
334	aead = crypto_spawn_aead(&ictx->u.aead_spawn);
335	if (IS_ERR(aead))
336	return PTR_ERR(aead);
337
c593642c	338	subreq_size = sizeof_field(struct essiv_aead_request_ctx, aead_req) +
be1eb7f7 AB	339	crypto_aead_reqsize(aead);
	340
	341	tctx->ivoffset = offsetof(struct essiv_aead_request_ctx, aead_req) +
	342	subreq_size;
	343	crypto_aead_set_reqsize(tfm, tctx->ivoffset + crypto_aead_ivsize(aead));
	344
	345	err = essiv_init_tfm(ictx, tctx);
	346	if (err) {
	347	crypto_free_aead(aead);
	348	return err;
	349	}
	350
	351	tctx->u.aead = aead;
	352	return 0;
	353	}
	354
	355	static void essiv_skcipher_exit_tfm(struct crypto_skcipher *tfm)
	356	{
	357	struct essiv_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
	358
	359	crypto_free_skcipher(tctx->u.skcipher);
	360	crypto_free_cipher(tctx->essiv_cipher);
	361	crypto_free_shash(tctx->hash);
	362	}
	363
	364	static void essiv_aead_exit_tfm(struct crypto_aead *tfm)
	365	{
	366	struct essiv_tfm_ctx *tctx = crypto_aead_ctx(tfm);
	367
	368	crypto_free_aead(tctx->u.aead);
	369	crypto_free_cipher(tctx->essiv_cipher);
	370	crypto_free_shash(tctx->hash);
	371	}
	372
	373	static void essiv_skcipher_free_instance(struct skcipher_instance *inst)
	374	{
	375	struct essiv_instance_ctx *ictx = skcipher_instance_ctx(inst);
	376
	377	crypto_drop_skcipher(&ictx->u.skcipher_spawn);
	378	kfree(inst);
	379	}
	380
	381	static void essiv_aead_free_instance(struct aead_instance *inst)
	382	{
	383	struct essiv_instance_ctx *ictx = aead_instance_ctx(inst);
	384
	385	crypto_drop_aead(&ictx->u.aead_spawn);
	386	kfree(inst);
	387	}
	388
	389	static bool parse_cipher_name(char essiv_cipher_name, const char cra_name)
	390	{
	391	const char p, q;
	392	int len;
	393
	394	/* find the last opening parens */
	395	p = strrchr(cra_name, '(');
	396	if (!p++)
	397	return false;
	398
	399	/* find the first closing parens in the tail of the string */
	400	q = strchr(p, ')');
	401	if (!q)
	402	return false;
403
404	len = q - p;
405	if (len >= CRYPTO_MAX_ALG_NAME)
406	return false;
407
408	memcpy(essiv_cipher_name, p, len);
409	essiv_cipher_name[len] = '\0';
410	return true;
411	}
412
413	static bool essiv_supported_algorithms(const char *essiv_cipher_name,
414	struct shash_alg *hash_alg,
415	int ivsize)
416	{
417	struct crypto_alg *alg;
418	bool ret = false;
419
420	alg = crypto_alg_mod_lookup(essiv_cipher_name,
421	CRYPTO_ALG_TYPE_CIPHER,
422	CRYPTO_ALG_TYPE_MASK);
423	if (IS_ERR(alg))
424	return false;
425
426	if (hash_alg->digestsize < alg->cra_cipher.cia_min_keysize \|\|
427	hash_alg->digestsize > alg->cra_cipher.cia_max_keysize)
428	goto out;
429
430	if (ivsize != alg->cra_blocksize)
431	goto out;
432
c2881789	433	if (crypto_shash_alg_needs_key(hash_alg))
be1eb7f7 AB	434	goto out;
	435
	436	ret = true;
	437
	438	out:
	439	crypto_mod_put(alg);
	440	return ret;
	441	}
	442
	443	static int essiv_create(struct crypto_template tmpl, struct rtattr *tb)
	444	{
4822ed7e	445	struct skcipher_alg_common *skcipher_alg = NULL;
be1eb7f7 AB	446	struct crypto_attr_type *algt;
	447	const char *inner_cipher_name;
	448	const char *shash_name;
	449	struct skcipher_instance *skcipher_inst = NULL;
	450	struct aead_instance *aead_inst = NULL;
	451	struct crypto_instance *inst;
	452	struct crypto_alg base, block_base;
	453	struct essiv_instance_ctx *ictx;
be1eb7f7 AB	454	struct aead_alg *aead_alg = NULL;
	455	struct crypto_alg *_hash_alg;
	456	struct shash_alg *hash_alg;
	457	int ivsize;
	458	u32 type;
b9f76ddd	459	u32 mask;
be1eb7f7 AB	460	int err;
	461
	462	algt = crypto_get_attr_type(tb);
	463	if (IS_ERR(algt))
	464	return PTR_ERR(algt);
	465
	466	inner_cipher_name = crypto_attr_alg_name(tb[1]);
	467	if (IS_ERR(inner_cipher_name))
	468	return PTR_ERR(inner_cipher_name);
	469
	470	shash_name = crypto_attr_alg_name(tb[2]);
	471	if (IS_ERR(shash_name))
	472	return PTR_ERR(shash_name);
	473
	474	type = algt->type & algt->mask;
7bcb2c99	475	mask = crypto_algt_inherited_mask(algt);
be1eb7f7 AB	476
be1eb7f7 AB	477	switch (type) {
4822ed7e	478	case CRYPTO_ALG_TYPE_LSKCIPHER:
be1eb7f7 AB	479	skcipher_inst = kzalloc(sizeof(*skcipher_inst) +
	480	sizeof(*ictx), GFP_KERNEL);
	481	if (!skcipher_inst)
	482	return -ENOMEM;
	483	inst = skcipher_crypto_instance(skcipher_inst);
	484	base = &skcipher_inst->alg.base;
	485	ictx = crypto_instance_ctx(inst);
	486
	487	/* Symmetric cipher, e.g., "cbc(aes)" */
b9f76ddd EB	488	err = crypto_grab_skcipher(&ictx->u.skcipher_spawn, inst,
b9f76ddd EB	489	inner_cipher_name, 0, mask);
be1eb7f7 AB	490	if (err)
be1eb7f7 AB	491	goto out_free_inst;
4822ed7e HX	492	skcipher_alg = crypto_spawn_skcipher_alg_common(
4822ed7e HX	493	&ictx->u.skcipher_spawn);
be1eb7f7	494	block_base = &skcipher_alg->base;
4822ed7e	495	ivsize = skcipher_alg->ivsize;
be1eb7f7 AB	496	break;
	497
	498	case CRYPTO_ALG_TYPE_AEAD:
	499	aead_inst = kzalloc(sizeof(*aead_inst) +
	500	sizeof(*ictx), GFP_KERNEL);
	501	if (!aead_inst)
	502	return -ENOMEM;
	503	inst = aead_crypto_instance(aead_inst);
	504	base = &aead_inst->alg.base;
	505	ictx = crypto_instance_ctx(inst);
	506
	507	/* AEAD cipher, e.g., "authenc(hmac(sha256),cbc(aes))" */
cd900f0c	508	err = crypto_grab_aead(&ictx->u.aead_spawn, inst,
b9f76ddd	509	inner_cipher_name, 0, mask);
be1eb7f7 AB	510	if (err)
	511	goto out_free_inst;
	512	aead_alg = crypto_spawn_aead_alg(&ictx->u.aead_spawn);
	513	block_base = &aead_alg->base;
	514	if (!strstarts(block_base->cra_name, "authenc(")) {
	515	pr_warn("Only authenc() type AEADs are supported by ESSIV\n");
	516	err = -EINVAL;
	517	goto out_drop_skcipher;
	518	}
	519	ivsize = aead_alg->ivsize;
	520	break;
	521
	522	default:
	523	return -EINVAL;
	524	}
	525
	526	if (!parse_cipher_name(ictx->essiv_cipher_name, block_base->cra_name)) {
	527	pr_warn("Failed to parse ESSIV cipher name from skcipher cra_name\n");
	528	err = -EINVAL;
	529	goto out_drop_skcipher;
	530	}
	531
	532	/* Synchronous hash, e.g., "sha256" */
	533	_hash_alg = crypto_alg_mod_lookup(shash_name,
	534	CRYPTO_ALG_TYPE_SHASH,
7bcb2c99	535	CRYPTO_ALG_TYPE_MASK \| mask);
be1eb7f7 AB	536	if (IS_ERR(_hash_alg)) {
	537	err = PTR_ERR(_hash_alg);
	538	goto out_drop_skcipher;
	539	}
	540	hash_alg = __crypto_shash_alg(_hash_alg);
	541
	542	/* Check the set of algorithms */
	543	if (!essiv_supported_algorithms(ictx->essiv_cipher_name, hash_alg,
	544	ivsize)) {
	545	pr_warn("Unsupported essiv instantiation: essiv(%s,%s)\n",
	546	block_base->cra_name, hash_alg->base.cra_name);
	547	err = -EINVAL;
	548	goto out_free_hash;
	549	}
	550
	551	/* record the driver name so we can instantiate this exact algo later */
dd4f8ee7	552	strscpy(ictx->shash_driver_name, hash_alg->base.cra_driver_name,
be1eb7f7 AB	553	CRYPTO_MAX_ALG_NAME);
	554
	555	/* Instance fields */
	556
	557	err = -ENAMETOOLONG;
	558	if (snprintf(base->cra_name, CRYPTO_MAX_ALG_NAME,
	559	"essiv(%s,%s)", block_base->cra_name,
	560	hash_alg->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
	561	goto out_free_hash;
	562	if (snprintf(base->cra_driver_name, CRYPTO_MAX_ALG_NAME,
	563	"essiv(%s,%s)", block_base->cra_driver_name,
	564	hash_alg->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
	565	goto out_free_hash;
	566
7bcb2c99 EB	567	/*
	568	* hash_alg wasn't gotten via crypto_grab*(), so we need to inherit its
	569	* flags manually.
	570	*/
	571	base->cra_flags \|= (hash_alg->base.cra_flags &
	572	CRYPTO_ALG_INHERITED_FLAGS);
be1eb7f7 AB	573	base->cra_blocksize = block_base->cra_blocksize;
	574	base->cra_ctxsize = sizeof(struct essiv_tfm_ctx);
	575	base->cra_alignmask = block_base->cra_alignmask;
	576	base->cra_priority = block_base->cra_priority;
	577
4822ed7e	578	if (type == CRYPTO_ALG_TYPE_LSKCIPHER) {
be1eb7f7 AB	579	skcipher_inst->alg.setkey = essiv_skcipher_setkey;
	580	skcipher_inst->alg.encrypt = essiv_skcipher_encrypt;
	581	skcipher_inst->alg.decrypt = essiv_skcipher_decrypt;
	582	skcipher_inst->alg.init = essiv_skcipher_init_tfm;
	583	skcipher_inst->alg.exit = essiv_skcipher_exit_tfm;
	584
4822ed7e HX	585	skcipher_inst->alg.min_keysize = skcipher_alg->min_keysize;
4822ed7e HX	586	skcipher_inst->alg.max_keysize = skcipher_alg->max_keysize;
be1eb7f7	587	skcipher_inst->alg.ivsize = ivsize;
4822ed7e	588	skcipher_inst->alg.chunksize = skcipher_alg->chunksize;
be1eb7f7 AB	589
	590	skcipher_inst->free = essiv_skcipher_free_instance;
	591
	592	err = skcipher_register_instance(tmpl, skcipher_inst);
	593	} else {
	594	aead_inst->alg.setkey = essiv_aead_setkey;
	595	aead_inst->alg.setauthsize = essiv_aead_setauthsize;
	596	aead_inst->alg.encrypt = essiv_aead_encrypt;
	597	aead_inst->alg.decrypt = essiv_aead_decrypt;
	598	aead_inst->alg.init = essiv_aead_init_tfm;
	599	aead_inst->alg.exit = essiv_aead_exit_tfm;
	600
	601	aead_inst->alg.ivsize = ivsize;
	602	aead_inst->alg.maxauthsize = crypto_aead_alg_maxauthsize(aead_alg);
	603	aead_inst->alg.chunksize = crypto_aead_alg_chunksize(aead_alg);
	604
	605	aead_inst->free = essiv_aead_free_instance;
	606
	607	err = aead_register_instance(tmpl, aead_inst);
	608	}
	609
	610	if (err)
	611	goto out_free_hash;
	612
	613	crypto_mod_put(_hash_alg);
	614	return 0;
	615
	616	out_free_hash:
	617	crypto_mod_put(_hash_alg);
	618	out_drop_skcipher:
4822ed7e	619	if (type == CRYPTO_ALG_TYPE_LSKCIPHER)
be1eb7f7 AB	620	crypto_drop_skcipher(&ictx->u.skcipher_spawn);
	621	else
	622	crypto_drop_aead(&ictx->u.aead_spawn);
	623	out_free_inst:
	624	kfree(skcipher_inst);
	625	kfree(aead_inst);
	626	return err;
	627	}
	628
	629	/* essiv(cipher_name, shash_name) */
	630	static struct crypto_template essiv_tmpl = {
	631	.name = "essiv",
	632	.create = essiv_create,
	633	.module = THIS_MODULE,
	634	};
	635
	636	static int __init essiv_module_init(void)
	637	{
	638	return crypto_register_template(&essiv_tmpl);
	639	}
	640
	641	static void __exit essiv_module_exit(void)
	642	{
	643	crypto_unregister_template(&essiv_tmpl);
	644	}
	645
	646	subsys_initcall(essiv_module_init);
	647	module_exit(essiv_module_exit);
	648
	649	MODULE_DESCRIPTION("ESSIV skcipher/aead wrapper for block encryption");
	650	MODULE_LICENSE("GPL v2");
	651	MODULE_ALIAS_CRYPTO("essiv");
0eb76ba2	652	MODULE_IMPORT_NS(CRYPTO_INTERNAL);