/* $OpenBSD: cbc128.c,v 1.5 2022/01/22 00:45:17 inoguchi Exp $ */

/* ====================================================================

 * Copyright (c) 2008 The OpenSSL Project.  All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer. 

 *

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in

 *    the documentation and/or other materials provided with the

 *    distribution.

 *

 * 3. All advertising materials mentioning features or use of this

 *    software must display the following acknowledgment:

 *    "This product includes software developed by the OpenSSL Project

 *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"

 *

 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to

 *    endorse or promote products derived from this software without

 *    prior written permission. For written permission, please contact

 *    openssl-core@openssl.org.

 *

 * 5. Products derived from this software may not be called "OpenSSL"

 *    nor may "OpenSSL" appear in their names without prior written

 *    permission of the OpenSSL Project.

 *

 * 6. Redistributions of any form whatsoever must retain the following

 *    acknowledgment:

 *    "This product includes software developed by the OpenSSL Project

 *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"

 *

 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY

 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR

 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;

 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,

 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED

 * OF THE POSSIBILITY OF SUCH DAMAGE.

 * ====================================================================

 *

 */

#include <openssl/crypto.h>

#include "modes_lcl.h"

#include <string.h>

#ifndef MODES_DEBUG

# ifndef NDEBUG

#  define NDEBUG

# endif

#endif

#undef STRICT_ALIGNMENT

#ifdef __STRICT_ALIGNMENT

#define STRICT_ALIGNMENT 1

#else

#define STRICT_ALIGNMENT 0

#endif

void CRYPTO_cbc128_encrypt(const unsigned char *in, unsigned char *out,

      size_t len, const void *key,

      unsigned char ivec[16], block128_f block)

{

  size_t n;

  const unsigned char *iv = ivec;

#if !defined(OPENSSL_SMALL_FOOTPRINT)

  if (STRICT_ALIGNMENT &&

      ((size_t)in|(size_t)out|(size_t)ivec)%sizeof(size_t) != 0) {

    while (len>=16) {

      for(n=0; n<16; ++n)

        out[n] = in[n] ^ iv[n];

      (*block)(out, out, key);

      iv = out;

      len -= 16;

      in  += 16;

      out += 16;

    }

  } else {

    while (len>=16) {

      for(n=0; n<16; n+=sizeof(size_t))

        *(size_t*)(out+n) =

        *(size_t*)(in+n) ^ *(size_t*)(iv+n);

      (*block)(out, out, key);

      iv = out;

      len -= 16;

      in  += 16;

      out += 16;

    }

  }

#endif

  while (len) {

    for(n=0; n<16 && n<len; ++n)

      out[n] = in[n] ^ iv[n];

    for(; n<16; ++n)

      out[n] = iv[n];

    (*block)(out, out, key);

    iv = out;

    if (len<=16) break;

    len -= 16;

    in  += 16;

    out += 16;

  }

  memmove(ivec,iv,16);

}

void CRYPTO_cbc128_decrypt(const unsigned char *in, unsigned char *out,

      size_t len, const void *key,

      unsigned char ivec[16], block128_f block)

{

  size_t n;

  union { size_t t[16/sizeof(size_t)]; unsigned char c[16]; } tmp;

#if !defined(OPENSSL_SMALL_FOOTPRINT)

  if (in != out) {

    const unsigned char *iv = ivec;

    if (STRICT_ALIGNMENT &&

        ((size_t)in|(size_t)out|(size_t)ivec)%sizeof(size_t) != 0) {

      while (len>=16) {

        (*block)(in, out, key);

        for(n=0; n<16; ++n)

          out[n] ^= iv[n];

        iv = in;

        len -= 16;

        in  += 16;

        out += 16;

      }

    } else if (16%sizeof(size_t) == 0) { /* always true */

      while (len>=16) {

        size_t *out_t=(size_t *)out, *iv_t=(size_t *)iv;

        (*block)(in, out, key);

        for(n=0; n<16/sizeof(size_t); n++)

          out_t[n] ^= iv_t[n];

        iv = in;

        len -= 16;

        in  += 16;

        out += 16;

      }

    }

    memmove(ivec,iv,16);

  } else {

    if (STRICT_ALIGNMENT &&

        ((size_t)in|(size_t)out|(size_t)ivec)%sizeof(size_t) != 0) {

      unsigned char c;

      while (len>=16) {

        (*block)(in, tmp.c, key);

        for(n=0; n<16; ++n) {

          c = in[n];

          out[n] = tmp.c[n] ^ ivec[n];

          ivec[n] = c;

        }

        len -= 16;

        in  += 16;

        out += 16;

      }

    } else if (16%sizeof(size_t) == 0) { /* always true */

      while (len>=16) {

        size_t c, *out_t=(size_t *)out, *ivec_t=(size_t *)ivec;

        const size_t *in_t=(const size_t *)in;

        (*block)(in, tmp.c, key);

        for(n=0; n<16/sizeof(size_t); n++) {

          c = in_t[n];

          out_t[n] = tmp.t[n] ^ ivec_t[n];

          ivec_t[n] = c;

        }

        len -= 16;

        in  += 16;

        out += 16;

      }

    }

  }

#endif

  while (len) {

    unsigned char c;

    (*block)(in, tmp.c, key);

    for(n=0; n<16 && n<len; ++n) {

      c = in[n];

      out[n] = tmp.c[n] ^ ivec[n];

      ivec[n] = c;

    }

    if (len<=16) {

      for (; n<16; ++n)

        ivec[n] = in[n];

      break;

    }

    len -= 16;

    in  += 16;

    out += 16;

  }

}