/*

 * LUKS anti-forensic (AF) diffuser functions

 *

 * Copyright (C) 2013-2024, Joachim Metz <joachim.metz@gmail.com>

 *

 * Refer to AUTHORS for acknowledgements.

 *

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

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

 * the Free Software Foundation, either version 3 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public License

 * along with this program.  If not, see <https://www.gnu.org/licenses/>.

 */

#include <common.h>

#include <byte_stream.h>

#include <memory.h>

#include <types.h>

#include "libluksde_definitions.h"

#include "libluksde_diffuser.h"

#include "libluksde_libcerror.h"

#include "libluksde_libcnotify.h"

#include "libluksde_libhmac.h"

/* Diffuses data

 * Returns 1 if successful or -1 on error

 */

int libluksde_diffuser_diffuse(

     uint8_t *data,

     size_t data_size,

     int hashing_method,

     libcerror_error_t **error )

{

  uint8_t block_index_buffer[ 4 ];

  uint8_t hash_buffer[ 64 ];

  libhmac_sha1_context_t *sha1_context     = NULL;

  libhmac_sha224_context_t *sha224_context = NULL;

  libhmac_sha256_context_t *sha256_context = NULL;

  libhmac_sha512_context_t *sha512_context = NULL;

  static char *function                    = "libluksde_diffuser_diffuse";

  size_t data_offset                       = 0;

  size_t hash_size                         = 0;

  size_t read_size                         = 0;

  uint32_t block_index                     = 0;

  int result                               = 0;

  if( data == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_INVALID_VALUE,

     "%s: invalid data.",

     function );

    return( -1 );

  }

#if SIZEOF_SIZE_T <= 4

  if( data_size > (size_t) SSIZE_MAX )

#else

  if( data_size > (size_t) UINT32_MAX )

#endif

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_VALUE_EXCEEDS_MAXIMUM,

     "%s: invalid data size value exceeds maximum.",

     function );

    return( -1 );

  }

  switch( hashing_method )

  {

    case LIBLUKSDE_HASHING_METHOD_SHA1:

      hash_size = LIBHMAC_SHA1_HASH_SIZE;

      break;

    case LIBLUKSDE_HASHING_METHOD_SHA224:

      hash_size = LIBHMAC_SHA224_HASH_SIZE;

      break;

    case LIBLUKSDE_HASHING_METHOD_SHA256:

      hash_size = LIBHMAC_SHA256_HASH_SIZE;

      break;

    case LIBLUKSDE_HASHING_METHOD_SHA512:

      hash_size = LIBHMAC_SHA512_HASH_SIZE;

      break;

    default:

      libcerror_error_set(

       error,

       LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

       LIBCERROR_ARGUMENT_ERROR_UNSUPPORTED_VALUE,

       "%s: unsupported hashing method.",

       function );

      return( -1 );

  }

  while( data_size > 0 )

  {

    switch( hashing_method )

    {

      case LIBLUKSDE_HASHING_METHOD_SHA1:

        result = libhmac_sha1_initialize(

            &sha1_context,

            error );

        break;

      case LIBLUKSDE_HASHING_METHOD_SHA224:

        result = libhmac_sha224_initialize(

            &sha224_context,

            error );

        break;

      case LIBLUKSDE_HASHING_METHOD_SHA256:

        result = libhmac_sha256_initialize(

            &sha256_context,

            error );

        break;

      case LIBLUKSDE_HASHING_METHOD_SHA512:

        result = libhmac_sha512_initialize(

            &sha512_context,

            error );

        break;

      default:

        result = 0;

        break;

    }

    if( result != 1 )

    {

      libcerror_error_set(

       error,

       LIBCERROR_ERROR_DOMAIN_RUNTIME,

       LIBCERROR_RUNTIME_ERROR_INITIALIZE_FAILED,

       "%s: unable to initialize context.",

       function );

      goto on_error;

    }

    byte_stream_copy_from_uint32_big_endian(

     block_index_buffer,

     block_index );

    switch( hashing_method )

    {

      case LIBLUKSDE_HASHING_METHOD_SHA1:

        result = libhmac_sha1_update(

                  sha1_context,

                  block_index_buffer,

                  4,

                  error );

        break;

      case LIBLUKSDE_HASHING_METHOD_SHA224:

        result = libhmac_sha224_update(

                  sha224_context,

                  block_index_buffer,

                  4,

                  error );

        break;

      case LIBLUKSDE_HASHING_METHOD_SHA256:

        result = libhmac_sha256_update(

                  sha256_context,

                  block_index_buffer,

                  4,

                  error );

        break;

      case LIBLUKSDE_HASHING_METHOD_SHA512:

        result = libhmac_sha512_update(

                  sha512_context,

                  block_index_buffer,

                  4,

                  error );

        break;

      default:

        result = 0;

        break;

    }

    if( result != 1 )

    {

      libcerror_error_set(

       error,

       LIBCERROR_ERROR_DOMAIN_RUNTIME,

       LIBCERROR_RUNTIME_ERROR_SET_FAILED,

       "%s: unable to update context.",

       function );

      goto on_error;

    }

    if( data_size < hash_size )

    {

      read_size = data_size;

    }

    else

    {

      read_size = hash_size;

    }

    switch( hashing_method )

    {

      case LIBLUKSDE_HASHING_METHOD_SHA1:

        result = libhmac_sha1_update(

                  sha1_context,

                  &( data[ data_offset ] ),

                  read_size,

                  error );

        break;

      case LIBLUKSDE_HASHING_METHOD_SHA224:

        result = libhmac_sha224_update(

                  sha224_context,

                  &( data[ data_offset ] ),

                  read_size,

                  error );

        break;

      case LIBLUKSDE_HASHING_METHOD_SHA256:

        result = libhmac_sha256_update(

                  sha256_context,

                  &( data[ data_offset ] ),

                  read_size,

                  error );

        break;

      case LIBLUKSDE_HASHING_METHOD_SHA512:

        result = libhmac_sha512_update(

                  sha512_context,

                  &( data[ data_offset ] ),

                  read_size,

                  error );

        break;

      default:

        result = 0;

        break;

    }

    if( result != 1 )

    {

      libcerror_error_set(

       error,

       LIBCERROR_ERROR_DOMAIN_RUNTIME,

       LIBCERROR_RUNTIME_ERROR_SET_FAILED,

       "%s: unable to update context.",

       function );

      goto on_error;

    }

    switch( hashing_method )

    {

      case LIBLUKSDE_HASHING_METHOD_SHA1:

        result = libhmac_sha1_finalize(

                  sha1_context,

                  hash_buffer,

                  hash_size,

                  error );

        break;

      case LIBLUKSDE_HASHING_METHOD_SHA224:

        result = libhmac_sha224_finalize(

                  sha224_context,

                  hash_buffer,

                  hash_size,

                  error );

        break;

      case LIBLUKSDE_HASHING_METHOD_SHA256:

        result = libhmac_sha256_finalize(

                  sha256_context,

                  hash_buffer,

                  hash_size,

                  error );

        break;

      case LIBLUKSDE_HASHING_METHOD_SHA512:

        result = libhmac_sha512_finalize(

                  sha512_context,

                  hash_buffer,

                  hash_size,

                  error );

        break;

      default:

        result = 0;

        break;

    }

    if( result != 1 )

    {

      libcerror_error_set(

       error,

       LIBCERROR_ERROR_DOMAIN_RUNTIME,

       LIBCERROR_RUNTIME_ERROR_FINALIZE_FAILED,

       "%s: unable to finalize context.",

       function );

      goto on_error;

    }

    switch( hashing_method )

    {

      case LIBLUKSDE_HASHING_METHOD_SHA1:

        result = libhmac_sha1_free(

                  &sha1_context,

                  error );

        break;

      case LIBLUKSDE_HASHING_METHOD_SHA224:

        result = libhmac_sha224_free(

                  &sha224_context,

                  error );

        break;

      case LIBLUKSDE_HASHING_METHOD_SHA256:

        result = libhmac_sha256_free(

                  &sha256_context,

                  error );

        break;

      case LIBLUKSDE_HASHING_METHOD_SHA512:

        result = libhmac_sha512_free(

                  &sha512_context,

                  error );

        break;

      default:

        result = 0;

        break;

    }

    if( result != 1 )

    {

      libcerror_error_set(

       error,

       LIBCERROR_ERROR_DOMAIN_RUNTIME,

       LIBCERROR_RUNTIME_ERROR_FINALIZE_FAILED,

       "%s: unable to free context.",

       function );

      goto on_error;

    }

    if( memory_copy(

         &( data[ data_offset ] ),

         hash_buffer,

         read_size ) == NULL)

    {

      libcerror_error_set(

       error,

       LIBCERROR_ERROR_DOMAIN_MEMORY,

       LIBCERROR_MEMORY_ERROR_COPY_FAILED,

       "%s: unable to copy hash to data.",

       function );

      goto on_error;

    }

    data_offset += read_size;

    data_size   -= read_size;

    block_index++;

  }

  return( 1 );

on_error:

  if( sha512_context != NULL )

  {

    libhmac_sha512_free(

     &sha512_context,

     NULL );

  }

  if( sha256_context != NULL )

  {

    libhmac_sha256_free(

     &sha256_context,

     NULL );

  }

  if( sha224_context != NULL )

  {

    libhmac_sha224_free(

     &sha224_context,

     NULL );

  }

  if( sha1_context != NULL )

  {

    libhmac_sha1_free(

     &sha1_context,

     NULL );

  }

  return( -1 );

}

/* Merges the split data using the diffuser

 * Returns 1 if successful or -1 on error

 */

int libluksde_diffuser_merge(

     const uint8_t *split_data,

     size_t split_data_size,

     uint8_t *data,

     size_t data_size,

     uint32_t number_of_stripes,

     int hashing_method,

     libcerror_error_t **error )

{

  static char *function    = "libluksde_diffuser_merge";

  size_t data_offset       = 0;

  size_t split_data_offset = 0;

  uint32_t stripe_iterator = 0;

  if( split_data == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_INVALID_VALUE,

     "%s: invalid split data.",

     function );

    return( -1 );

  }

  if( ( split_data_size == 0 )

   || ( split_data_size > (size_t) SSIZE_MAX ) )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_VALUE_OUT_OF_BOUNDS,

     "%s: invalid split data size value out of bounds.",

     function );

    return( -1 );

  }

  if( data == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_INVALID_VALUE,

     "%s: invalid data.",

     function );

    return( -1 );

  }

  if( ( data_size == 0 )

   || ( data_size > split_data_size ) )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_ARGUMENTS,

     LIBCERROR_ARGUMENT_ERROR_VALUE_OUT_OF_BOUNDS,

     "%s: invalid data size value out of bounds.",

     function );

    return( -1 );

  }

  if( ( number_of_stripes < 1 )

   || ( number_of_stripes > ( split_data_size / data_size ) ) )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_RUNTIME,

     LIBCERROR_RUNTIME_ERROR_VALUE_OUT_OF_BOUNDS,

     "%s: number of stripes value out of bounds.",

     function );

    return( -1 );

  }

  if( memory_set(

       data,

       0,

       data_size ) == NULL )

  {

    libcerror_error_set(

     error,

     LIBCERROR_ERROR_DOMAIN_MEMORY,

     LIBCERROR_MEMORY_ERROR_SET_FAILED,

     "%s: unable to clear data.",

     function );

    return( -1 );

  }

  for( stripe_iterator = 0;

       stripe_iterator < ( number_of_stripes - 1 );

       stripe_iterator++ )

  {

    for( data_offset = 0;

         data_offset < data_size;

         data_offset++ )

    {

      data[ data_offset ] ^= split_data[ split_data_offset ];

      split_data_offset++;

    }

    if( libluksde_diffuser_diffuse(

         data,

         data_size,

         hashing_method,

         error ) != 1 )

    {

      libcerror_error_set(

       error,

       LIBCERROR_ERROR_DOMAIN_RUNTIME,

       LIBCERROR_RUNTIME_ERROR_GENERIC,

       "%s: unable to diffuse stripe: %" PRIu32 ".",

       function,

       stripe_iterator );

      return( -1 );

    }

  }

  for( data_offset = 0;

       data_offset < data_size;

       data_offset++ )

  {

    data[ data_offset ] ^= split_data[ split_data_offset ];

    split_data_offset++;

  }

  return( 1 );

}