crypto/pcbc.c - linux - Git at Google


            
            /*

            
             * PCBC: Propagating Cipher Block Chaining mode

            
             *

            
             * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.

            
             * Written by David Howells (dhowells@redhat.com)

            
             *

            
             * Derived from cbc.c

            
             * - Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>

            
             *

            
             * This program is free software; you can redistribute it and/or modify it

            
             * under the terms of the GNU General Public License as published by the Free

            
             * Software Foundation; either version 2 of the License, or (at your option)

            
             * any later version.

            
             *

            
             */


            #include <crypto/algapi.h>

            
            #include <linux/err.h>

            
            #include <linux/init.h>

            
            #include <linux/kernel.h>

            
            #include <linux/module.h>

            
            #include <linux/scatterlist.h>

            
            #include <linux/slab.h>


            struct crypto_pcbc_ctx {

            
            	struct crypto_cipher *child;

            
            	void (*xor)(u8 *dst, const u8 *src, unsigned int bs);

            
            };


            static int crypto_pcbc_setkey(struct crypto_tfm *parent, const u8 *key,

            
            			      unsigned int keylen)

            
            {

            
            	struct crypto_pcbc_ctx *ctx = crypto_tfm_ctx(parent);

            
            	struct crypto_cipher *child = ctx->child;

            
            	int err;


            	crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);

            
            	crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) &

            
            				CRYPTO_TFM_REQ_MASK);

            
            	err = crypto_cipher_setkey(child, key, keylen);

            
            	crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &

            
            			     CRYPTO_TFM_RES_MASK);

            
            	return err;

            
            }


            static int crypto_pcbc_encrypt_segment(struct blkcipher_desc *desc,

            
            				       struct blkcipher_walk *walk,

            
            				       struct crypto_cipher *tfm,

            
            				       void (*xor)(u8 *, const u8 *,

            
            						   unsigned int))

            
            {

            
            	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =

            
            		crypto_cipher_alg(tfm)->cia_encrypt;

            
            	int bsize = crypto_cipher_blocksize(tfm);

            
            	unsigned int nbytes = walk->nbytes;

            
            	u8 *src = walk->src.virt.addr;

            
            	u8 *dst = walk->dst.virt.addr;

            
            	u8 *iv = walk->iv;


            	do {

            
            		xor(iv, src, bsize);

            
            		fn(crypto_cipher_tfm(tfm), dst, iv);

            
            		memcpy(iv, dst, bsize);

            
            		xor(iv, src, bsize);


            		src += bsize;

            
            		dst += bsize;

            
            	} while ((nbytes -= bsize) >= bsize);


            	return nbytes;

            
            }


            static int crypto_pcbc_encrypt_inplace(struct blkcipher_desc *desc,

            
            				       struct blkcipher_walk *walk,

            
            				       struct crypto_cipher *tfm,

            
            				       void (*xor)(u8 *, const u8 *,

            
            						   unsigned int))

            
            {

            
            	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =

            
            		crypto_cipher_alg(tfm)->cia_encrypt;

            
            	int bsize = crypto_cipher_blocksize(tfm);

            
            	unsigned int nbytes = walk->nbytes;

            
            	u8 *src = walk->src.virt.addr;

            
            	u8 *iv = walk->iv;

            
            	u8 tmpbuf[bsize];


            	do {

            
            		memcpy(tmpbuf, src, bsize);

            
            		xor(iv, tmpbuf, bsize);

            
            		fn(crypto_cipher_tfm(tfm), src, iv);

            
            		memcpy(iv, src, bsize);

            
            		xor(iv, tmpbuf, bsize);


            		src += bsize;

            
            	} while ((nbytes -= bsize) >= bsize);


            	memcpy(walk->iv, iv, bsize);


            	return nbytes;

            
            }


            static int crypto_pcbc_encrypt(struct blkcipher_desc *desc,

            
            			       struct scatterlist *dst, struct scatterlist *src,

            
            			       unsigned int nbytes)

            
            {

            
            	struct blkcipher_walk walk;

            
            	struct crypto_blkcipher *tfm = desc->tfm;

            
            	struct crypto_pcbc_ctx *ctx = crypto_blkcipher_ctx(tfm);

            
            	struct crypto_cipher *child = ctx->child;

            
            	void (*xor)(u8 *, const u8 *, unsigned int bs) = ctx->xor;

            
            	int err;


            	blkcipher_walk_init(&walk, dst, src, nbytes);

            
            	err = blkcipher_walk_virt(desc, &walk);


            	while ((nbytes = walk.nbytes)) {

            
            		if (walk.src.virt.addr == walk.dst.virt.addr)

            
            			nbytes = crypto_pcbc_encrypt_inplace(desc, &walk, child,

            
            							     xor);

            
            		else

            
            			nbytes = crypto_pcbc_encrypt_segment(desc, &walk, child,

            
            							     xor);

            
            		err = blkcipher_walk_done(desc, &walk, nbytes);

            
            	}


            	return err;

            
            }


            static int crypto_pcbc_decrypt_segment(struct blkcipher_desc *desc,

            
            				       struct blkcipher_walk *walk,

            
            				       struct crypto_cipher *tfm,

            
            				       void (*xor)(u8 *, const u8 *,

            
            						   unsigned int))

            
            {

            
            	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =

            
            		crypto_cipher_alg(tfm)->cia_decrypt;

            
            	int bsize = crypto_cipher_blocksize(tfm);

            
            	unsigned int nbytes = walk->nbytes;

            
            	u8 *src = walk->src.virt.addr;

            
            	u8 *dst = walk->dst.virt.addr;

            
            	u8 *iv = walk->iv;


            	do {

            
            		fn(crypto_cipher_tfm(tfm), dst, src);

            
            		xor(dst, iv, bsize);

            
            		memcpy(iv, src, bsize);

            
            		xor(iv, dst, bsize);


            		src += bsize;

            
            		dst += bsize;

            
            	} while ((nbytes -= bsize) >= bsize);


            	memcpy(walk->iv, iv, bsize);


            	return nbytes;

            
            }


            static int crypto_pcbc_decrypt_inplace(struct blkcipher_desc *desc,

            
            				       struct blkcipher_walk *walk,

            
            				       struct crypto_cipher *tfm,

            
            				       void (*xor)(u8 *, const u8 *,

            
            						   unsigned int))

            
            {

            
            	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =

            
            		crypto_cipher_alg(tfm)->cia_decrypt;

            
            	int bsize = crypto_cipher_blocksize(tfm);

            
            	unsigned int nbytes = walk->nbytes;

            
            	u8 *src = walk->src.virt.addr;

            
            	u8 *iv = walk->iv;

            
            	u8 tmpbuf[bsize];


            	do {

            
            		memcpy(tmpbuf, src, bsize);

            
            		fn(crypto_cipher_tfm(tfm), src, src);

            
            		xor(src, iv, bsize);

            
            		memcpy(iv, tmpbuf, bsize);

            
            		xor(iv, src, bsize);


            		src += bsize;

            
            	} while ((nbytes -= bsize) >= bsize);


            	memcpy(walk->iv, iv, bsize);


            	return nbytes;

            
            }


            static int crypto_pcbc_decrypt(struct blkcipher_desc *desc,

            
            			       struct scatterlist *dst, struct scatterlist *src,

            
            			       unsigned int nbytes)

            
            {

            
            	struct blkcipher_walk walk;

            
            	struct crypto_blkcipher *tfm = desc->tfm;

            
            	struct crypto_pcbc_ctx *ctx = crypto_blkcipher_ctx(tfm);

            
            	struct crypto_cipher *child = ctx->child;

            
            	void (*xor)(u8 *, const u8 *, unsigned int bs) = ctx->xor;

            
            	int err;


            	blkcipher_walk_init(&walk, dst, src, nbytes);

            
            	err = blkcipher_walk_virt(desc, &walk);


            	while ((nbytes = walk.nbytes)) {

            
            		if (walk.src.virt.addr == walk.dst.virt.addr)

            
            			nbytes = crypto_pcbc_decrypt_inplace(desc, &walk, child,

            
            							     xor);

            
            		else

            
            			nbytes = crypto_pcbc_decrypt_segment(desc, &walk, child,

            
            							     xor);

            
            		err = blkcipher_walk_done(desc, &walk, nbytes);

            
            	}


            	return err;

            
            }


            static void xor_byte(u8 *a, const u8 *b, unsigned int bs)

            
            {

            
            	do {

            
            		*a++ ^= *b++;

            
            	} while (--bs);

            
            }


            static void xor_quad(u8 *dst, const u8 *src, unsigned int bs)

            
            {

            
            	u32 *a = (u32 *)dst;

            
            	u32 *b = (u32 *)src;


            	do {

            
            		*a++ ^= *b++;

            
            	} while ((bs -= 4));

            
            }


            static void xor_64(u8 *a, const u8 *b, unsigned int bs)

            
            {

            
            	((u32 *)a)[0] ^= ((u32 *)b)[0];

            
            	((u32 *)a)[1] ^= ((u32 *)b)[1];

            
            }


            static void xor_128(u8 *a, const u8 *b, unsigned int bs)

            
            {

            
            	((u32 *)a)[0] ^= ((u32 *)b)[0];

            
            	((u32 *)a)[1] ^= ((u32 *)b)[1];

            
            	((u32 *)a)[2] ^= ((u32 *)b)[2];

            
            	((u32 *)a)[3] ^= ((u32 *)b)[3];

            
            }


            static int crypto_pcbc_init_tfm(struct crypto_tfm *tfm)

            
            {

            
            	struct crypto_instance *inst = (void *)tfm->__crt_alg;

            
            	struct crypto_spawn *spawn = crypto_instance_ctx(inst);

            
            	struct crypto_pcbc_ctx *ctx = crypto_tfm_ctx(tfm);

            
            	struct crypto_cipher *cipher;


            	switch (crypto_tfm_alg_blocksize(tfm)) {

            
            	case 8:

            
            		ctx->xor = xor_64;

            
            		break;


            	case 16:

            
            		ctx->xor = xor_128;

            
            		break;


            	default:

            
            		if (crypto_tfm_alg_blocksize(tfm) % 4)

            
            			ctx->xor = xor_byte;

            
            		else

            
            			ctx->xor = xor_quad;

            
            	}


            	cipher = crypto_spawn_cipher(spawn);

            
            	if (IS_ERR(cipher))

            
            		return PTR_ERR(cipher);


            	ctx->child = cipher;

            
            	return 0;

            
            }


            static void crypto_pcbc_exit_tfm(struct crypto_tfm *tfm)

            
            {

            
            	struct crypto_pcbc_ctx *ctx = crypto_tfm_ctx(tfm);

            
            	crypto_free_cipher(ctx->child);

            
            }


            static struct crypto_instance *crypto_pcbc_alloc(void *param, unsigned int len)

            
            {

            
            	struct crypto_instance *inst;

            
            	struct crypto_alg *alg;


            	alg = crypto_get_attr_alg(param, len, CRYPTO_ALG_TYPE_CIPHER,

            
            				  CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_ASYNC);

            
            	if (IS_ERR(alg))

            
            		return ERR_PTR(PTR_ERR(alg));


            	inst = crypto_alloc_instance("pcbc", alg);

            
            	if (IS_ERR(inst))

            
            		goto out_put_alg;


            	inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;

            
            	inst->alg.cra_priority = alg->cra_priority;

            
            	inst->alg.cra_blocksize = alg->cra_blocksize;

            
            	inst->alg.cra_alignmask = alg->cra_alignmask;

            
            	inst->alg.cra_type = &crypto_blkcipher_type;


            	if (!(alg->cra_blocksize % 4))

            
            		inst->alg.cra_alignmask |= 3;

            
            	inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize;

            
            	inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize;

            
            	inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize;


            	inst->alg.cra_ctxsize = sizeof(struct crypto_pcbc_ctx);


            	inst->alg.cra_init = crypto_pcbc_init_tfm;

            
            	inst->alg.cra_exit = crypto_pcbc_exit_tfm;


            	inst->alg.cra_blkcipher.setkey = crypto_pcbc_setkey;

            
            	inst->alg.cra_blkcipher.encrypt = crypto_pcbc_encrypt;

            
            	inst->alg.cra_blkcipher.decrypt = crypto_pcbc_decrypt;


            out_put_alg:

            
            	crypto_mod_put(alg);

            
            	return inst;

            
            }


            static void crypto_pcbc_free(struct crypto_instance *inst)

            
            {

            
            	crypto_drop_spawn(crypto_instance_ctx(inst));

            
            	kfree(inst);

            
            }


            static struct crypto_template crypto_pcbc_tmpl = {

            
            	.name = "pcbc",

            
            	.alloc = crypto_pcbc_alloc,

            
            	.free = crypto_pcbc_free,

            
            	.module = THIS_MODULE,

            
            };


            static int __init crypto_pcbc_module_init(void)

            
            {

            
            	return crypto_register_template(&crypto_pcbc_tmpl);

            
            }


            static void __exit crypto_pcbc_module_exit(void)

            
            {

            
            	crypto_unregister_template(&crypto_pcbc_tmpl);

            
            }


            module_init(crypto_pcbc_module_init);

            
            module_exit(crypto_pcbc_module_exit);


            MODULE_LICENSE("GPL");

            
            MODULE_DESCRIPTION("PCBC block cipher algorithm");
	/*
	* PCBC: Propagating Cipher Block Chaining mode
	*
	* Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
	* Written by David Howells (dhowells@redhat.com)
	*
	* Derived from cbc.c
	* - Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
	*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License as published by the Free
	* Software Foundation; either version 2 of the License, or (at your option)
	* any later version.
	*
	*/

	#include <crypto/algapi.h>
	#include <linux/err.h>
	#include <linux/init.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/scatterlist.h>
	#include <linux/slab.h>

	struct crypto_pcbc_ctx {
	struct crypto_cipher *child;
	void (xor)(u8 dst, const u8 *src, unsigned int bs);
	};

	static int crypto_pcbc_setkey(struct crypto_tfm parent, const u8 key,
	unsigned int keylen)
	{
	struct crypto_pcbc_ctx *ctx = crypto_tfm_ctx(parent);
	struct crypto_cipher *child = ctx->child;
	int err;

	crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
	crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) &
	CRYPTO_TFM_REQ_MASK);
	err = crypto_cipher_setkey(child, key, keylen);
	crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &
	CRYPTO_TFM_RES_MASK);
	return err;
	}

	static int crypto_pcbc_encrypt_segment(struct blkcipher_desc *desc,
	struct blkcipher_walk *walk,
	struct crypto_cipher *tfm,
	void (xor)(u8 , const u8 *,
	unsigned int))
	{
	void (fn)(struct crypto_tfm , u8 , const u8 ) =
	crypto_cipher_alg(tfm)->cia_encrypt;
	int bsize = crypto_cipher_blocksize(tfm);
	unsigned int nbytes = walk->nbytes;
	u8 *src = walk->src.virt.addr;
	u8 *dst = walk->dst.virt.addr;
	u8 *iv = walk->iv;

	do {
	xor(iv, src, bsize);
	fn(crypto_cipher_tfm(tfm), dst, iv);
	memcpy(iv, dst, bsize);
	xor(iv, src, bsize);

	src += bsize;
	dst += bsize;
	} while ((nbytes -= bsize) >= bsize);

	return nbytes;
	}

	static int crypto_pcbc_encrypt_inplace(struct blkcipher_desc *desc,
	struct blkcipher_walk *walk,
	struct crypto_cipher *tfm,
	void (xor)(u8 , const u8 *,
	unsigned int))
	{
	void (fn)(struct crypto_tfm , u8 , const u8 ) =
	crypto_cipher_alg(tfm)->cia_encrypt;
	int bsize = crypto_cipher_blocksize(tfm);
	unsigned int nbytes = walk->nbytes;
	u8 *src = walk->src.virt.addr;
	u8 *iv = walk->iv;
	u8 tmpbuf[bsize];

	do {
	memcpy(tmpbuf, src, bsize);
	xor(iv, tmpbuf, bsize);
	fn(crypto_cipher_tfm(tfm), src, iv);
	memcpy(iv, src, bsize);
	xor(iv, tmpbuf, bsize);

	src += bsize;
	} while ((nbytes -= bsize) >= bsize);

	memcpy(walk->iv, iv, bsize);

	return nbytes;
	}

	static int crypto_pcbc_encrypt(struct blkcipher_desc *desc,
	struct scatterlist dst, struct scatterlist src,
	unsigned int nbytes)
	{
	struct blkcipher_walk walk;
	struct crypto_blkcipher *tfm = desc->tfm;
	struct crypto_pcbc_ctx *ctx = crypto_blkcipher_ctx(tfm);
	struct crypto_cipher *child = ctx->child;
	void (xor)(u8 , const u8 *, unsigned int bs) = ctx->xor;
	int err;

	blkcipher_walk_init(&walk, dst, src, nbytes);
	err = blkcipher_walk_virt(desc, &walk);

	while ((nbytes = walk.nbytes)) {
	if (walk.src.virt.addr == walk.dst.virt.addr)
	nbytes = crypto_pcbc_encrypt_inplace(desc, &walk, child,
	xor);
	else
	nbytes = crypto_pcbc_encrypt_segment(desc, &walk, child,
	xor);
	err = blkcipher_walk_done(desc, &walk, nbytes);
	}

	return err;
	}

	static int crypto_pcbc_decrypt_segment(struct blkcipher_desc *desc,
	struct blkcipher_walk *walk,
	struct crypto_cipher *tfm,
	void (xor)(u8 , const u8 *,
	unsigned int))
	{
	void (fn)(struct crypto_tfm , u8 , const u8 ) =
	crypto_cipher_alg(tfm)->cia_decrypt;
	int bsize = crypto_cipher_blocksize(tfm);
	unsigned int nbytes = walk->nbytes;
	u8 *src = walk->src.virt.addr;
	u8 *dst = walk->dst.virt.addr;
	u8 *iv = walk->iv;

	do {
	fn(crypto_cipher_tfm(tfm), dst, src);
	xor(dst, iv, bsize);
	memcpy(iv, src, bsize);
	xor(iv, dst, bsize);

	src += bsize;
	dst += bsize;
	} while ((nbytes -= bsize) >= bsize);

	memcpy(walk->iv, iv, bsize);

	return nbytes;
	}

	static int crypto_pcbc_decrypt_inplace(struct blkcipher_desc *desc,
	struct blkcipher_walk *walk,
	struct crypto_cipher *tfm,
	void (xor)(u8 , const u8 *,
	unsigned int))
	{
	void (fn)(struct crypto_tfm , u8 , const u8 ) =
	crypto_cipher_alg(tfm)->cia_decrypt;
	int bsize = crypto_cipher_blocksize(tfm);
	unsigned int nbytes = walk->nbytes;
	u8 *src = walk->src.virt.addr;
	u8 *iv = walk->iv;
	u8 tmpbuf[bsize];

	do {
	memcpy(tmpbuf, src, bsize);
	fn(crypto_cipher_tfm(tfm), src, src);
	xor(src, iv, bsize);
	memcpy(iv, tmpbuf, bsize);
	xor(iv, src, bsize);

	src += bsize;
	} while ((nbytes -= bsize) >= bsize);

	memcpy(walk->iv, iv, bsize);

	return nbytes;
	}

	static int crypto_pcbc_decrypt(struct blkcipher_desc *desc,
	struct scatterlist dst, struct scatterlist src,
	unsigned int nbytes)
	{
	struct blkcipher_walk walk;
	struct crypto_blkcipher *tfm = desc->tfm;
	struct crypto_pcbc_ctx *ctx = crypto_blkcipher_ctx(tfm);
	struct crypto_cipher *child = ctx->child;
	void (xor)(u8 , const u8 *, unsigned int bs) = ctx->xor;
	int err;

	blkcipher_walk_init(&walk, dst, src, nbytes);
	err = blkcipher_walk_virt(desc, &walk);

	while ((nbytes = walk.nbytes)) {
	if (walk.src.virt.addr == walk.dst.virt.addr)
	nbytes = crypto_pcbc_decrypt_inplace(desc, &walk, child,
	xor);
	else
	nbytes = crypto_pcbc_decrypt_segment(desc, &walk, child,
	xor);
	err = blkcipher_walk_done(desc, &walk, nbytes);
	}

	return err;
	}

	static void xor_byte(u8 a, const u8 b, unsigned int bs)
	{
	do {
	a++ ^= b++;
	} while (--bs);
	}

	static void xor_quad(u8 dst, const u8 src, unsigned int bs)
	{
	u32 a = (u32 )dst;
	u32 b = (u32 )src;

	do {
	a++ ^= b++;
	} while ((bs -= 4));
	}

	static void xor_64(u8 a, const u8 b, unsigned int bs)
	{
	((u32 )a)[0] ^= ((u32 )b)[0];
	((u32 )a)[1] ^= ((u32 )b)[1];
	}

	static void xor_128(u8 a, const u8 b, unsigned int bs)
	{
	((u32 )a)[0] ^= ((u32 )b)[0];
	((u32 )a)[1] ^= ((u32 )b)[1];
	((u32 )a)[2] ^= ((u32 )b)[2];
	((u32 )a)[3] ^= ((u32 )b)[3];
	}

	static int crypto_pcbc_init_tfm(struct crypto_tfm *tfm)
	{
	struct crypto_instance inst = (void )tfm->__crt_alg;
	struct crypto_spawn *spawn = crypto_instance_ctx(inst);
	struct crypto_pcbc_ctx *ctx = crypto_tfm_ctx(tfm);
	struct crypto_cipher *cipher;

	switch (crypto_tfm_alg_blocksize(tfm)) {
	case 8:
	ctx->xor = xor_64;
	break;

	case 16:
	ctx->xor = xor_128;
	break;

	default:
	if (crypto_tfm_alg_blocksize(tfm) % 4)
	ctx->xor = xor_byte;
	else
	ctx->xor = xor_quad;
	}

	cipher = crypto_spawn_cipher(spawn);
	if (IS_ERR(cipher))
	return PTR_ERR(cipher);

	ctx->child = cipher;
	return 0;
	}

	static void crypto_pcbc_exit_tfm(struct crypto_tfm *tfm)
	{
	struct crypto_pcbc_ctx *ctx = crypto_tfm_ctx(tfm);
	crypto_free_cipher(ctx->child);
	}

	static struct crypto_instance crypto_pcbc_alloc(void param, unsigned int len)
	{
	struct crypto_instance *inst;
	struct crypto_alg *alg;

	alg = crypto_get_attr_alg(param, len, CRYPTO_ALG_TYPE_CIPHER,
	CRYPTO_ALG_TYPE_MASK \| CRYPTO_ALG_ASYNC);
	if (IS_ERR(alg))
	return ERR_PTR(PTR_ERR(alg));

	inst = crypto_alloc_instance("pcbc", alg);
	if (IS_ERR(inst))
	goto out_put_alg;

	inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
	inst->alg.cra_priority = alg->cra_priority;
	inst->alg.cra_blocksize = alg->cra_blocksize;
	inst->alg.cra_alignmask = alg->cra_alignmask;
	inst->alg.cra_type = &crypto_blkcipher_type;

	if (!(alg->cra_blocksize % 4))
	inst->alg.cra_alignmask \|= 3;
	inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize;
	inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
	inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize;

	inst->alg.cra_ctxsize = sizeof(struct crypto_pcbc_ctx);

	inst->alg.cra_init = crypto_pcbc_init_tfm;
	inst->alg.cra_exit = crypto_pcbc_exit_tfm;

	inst->alg.cra_blkcipher.setkey = crypto_pcbc_setkey;
	inst->alg.cra_blkcipher.encrypt = crypto_pcbc_encrypt;
	inst->alg.cra_blkcipher.decrypt = crypto_pcbc_decrypt;

	out_put_alg:
	crypto_mod_put(alg);
	return inst;
	}

	static void crypto_pcbc_free(struct crypto_instance *inst)
	{
	crypto_drop_spawn(crypto_instance_ctx(inst));
	kfree(inst);
	}

	static struct crypto_template crypto_pcbc_tmpl = {
	.name = "pcbc",
	.alloc = crypto_pcbc_alloc,
	.free = crypto_pcbc_free,
	.module = THIS_MODULE,
	};

	static int __init crypto_pcbc_module_init(void)
	{
	return crypto_register_template(&crypto_pcbc_tmpl);
	}

	static void __exit crypto_pcbc_module_exit(void)
	{
	crypto_unregister_template(&crypto_pcbc_tmpl);
	}

	module_init(crypto_pcbc_module_init);
	module_exit(crypto_pcbc_module_exit);

	MODULE_LICENSE("GPL");
	MODULE_DESCRIPTION("PCBC block cipher algorithm");