linux-imx

/*

 * 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 <crypto/internal/skcipher.h>

#include <linux/err.h>

#include <linux/init.h>

#include <linux/kernel.h>

#include <linux/module.h>

​

static int crypto_pcbc_encrypt_segment(struct skcipher_request *req,

                       struct skcipher_walk *walk,

                       struct crypto_cipher *tfm)

{

    int bsize = crypto_cipher_blocksize(tfm);

    unsigned int nbytes = walk->nbytes;

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

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

    u8 * const iv = walk->iv;

​

    do {

        crypto_xor(iv, src, bsize);

        crypto_cipher_encrypt_one(tfm, dst, iv);

        crypto_xor_cpy(iv, dst, src, bsize);

​

        src += bsize;

        dst += bsize;

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

​

    return nbytes;

}

​

static int crypto_pcbc_encrypt_inplace(struct skcipher_request *req,

                       struct skcipher_walk *walk,

                       struct crypto_cipher *tfm)

{

    int bsize = crypto_cipher_blocksize(tfm);

    unsigned int nbytes = walk->nbytes;

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

    u8 * const iv = walk->iv;

    u8 tmpbuf[MAX_CIPHER_BLOCKSIZE];

​

    do {

        memcpy(tmpbuf, src, bsize);

        crypto_xor(iv, src, bsize);

        crypto_cipher_encrypt_one(tfm, src, iv);

        crypto_xor_cpy(iv, tmpbuf, src, bsize);

​

        src += bsize;

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