mirror of
https://gitlab.com/cryptsetup/cryptsetup.git
synced 2025-12-18 14:20:09 +01:00
98cf0aedf8
* write_lseek_blockwise: declare innerCount outside the if block * add -Wall to the default CFLAGS * fix some signedness issues git-svn-id: https://cryptsetup.googlecode.com/svn/trunk@29 36d66b0a-2a48-0410-832c-cd162a569da5
117 lines
3.4 KiB
C
117 lines
3.4 KiB
C
/*
|
|
* AFsplitter - Anti forensic information splitter
|
|
* Copyright 2004, Clemens Fruhwirth <clemens@endorphin.org>
|
|
*
|
|
* AFsplitter diffuses information over a large stripe of data,
|
|
* therefor supporting secure data destruction.
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* version 2 as published by the Free Software Foundation.
|
|
*
|
|
* 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 Library General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
|
|
*/
|
|
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <unistd.h>
|
|
#include <sys/types.h>
|
|
#include <sys/stat.h>
|
|
#include <fcntl.h>
|
|
#include <netinet/in.h>
|
|
#include <errno.h>
|
|
#include "sha1.h"
|
|
#include "XORblock.h"
|
|
#include "random.h"
|
|
|
|
/* diffuse: Information spreading over the whole dataset with
|
|
* the help of sha512.
|
|
*/
|
|
|
|
static void diffuse(unsigned char *src, unsigned char *dst, size_t size)
|
|
{
|
|
sha1_ctx ctx;
|
|
uint32_t i;
|
|
uint32_t IV; /* host byte order independend hash IV */
|
|
|
|
unsigned int fullblocks = size / SHA1_DIGEST_SIZE;
|
|
unsigned int padding = size % SHA1_DIGEST_SIZE;
|
|
unsigned char final[SHA1_DIGEST_SIZE];
|
|
|
|
/* hash block the whole data set with different IVs to produce
|
|
* more than just a single data block
|
|
*/
|
|
for (i=0; i < fullblocks; i++) {
|
|
sha1_begin(&ctx);
|
|
IV = htonl(i);
|
|
sha1_hash((const unsigned char *) &IV, sizeof(IV), &ctx);
|
|
sha1_hash(src + SHA1_DIGEST_SIZE * i, SHA1_DIGEST_SIZE, &ctx);
|
|
sha1_end(dst + SHA1_DIGEST_SIZE * i, &ctx);
|
|
}
|
|
|
|
if(padding) {
|
|
sha1_begin(&ctx);
|
|
IV = htonl(i);
|
|
sha1_hash((const unsigned char *) &IV, sizeof(IV), &ctx);
|
|
sha1_hash(src + SHA1_DIGEST_SIZE * i, padding, &ctx);
|
|
sha1_end(final, &ctx);
|
|
memcpy(dst + SHA1_DIGEST_SIZE * i, final, padding);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Information splitting. The amount of data is multiplied by
|
|
* blocknumbers. The same blocksize and blocknumbers values
|
|
* must be supplied to AF_merge to recover information.
|
|
*/
|
|
|
|
int AF_split(char *src, char *dst, size_t blocksize, unsigned int blocknumbers)
|
|
{
|
|
unsigned int i;
|
|
char *bufblock;
|
|
int r = -EINVAL;
|
|
|
|
if((bufblock = calloc(blocksize, 1)) == NULL) return -ENOMEM;
|
|
|
|
/* process everything except the last block */
|
|
for(i=0; i<blocknumbers-1; i++) {
|
|
r = getRandom(dst+(blocksize*i),blocksize);
|
|
if(r < 0) goto out;
|
|
|
|
XORblock(dst+(blocksize*i),bufblock,bufblock,blocksize);
|
|
diffuse((unsigned char *) bufblock, (unsigned char *) bufblock, blocksize);
|
|
}
|
|
/* the last block is computed */
|
|
XORblock(src,bufblock,dst+(i*blocksize),blocksize);
|
|
r = 0;
|
|
out:
|
|
free(bufblock);
|
|
return r;
|
|
}
|
|
|
|
int AF_merge(char *src, char *dst, size_t blocksize, unsigned int blocknumbers)
|
|
{
|
|
unsigned int i;
|
|
char *bufblock;
|
|
|
|
if((bufblock = calloc(blocksize, 1)) == NULL) return -ENOMEM;
|
|
|
|
memset(bufblock,0,blocksize);
|
|
for(i=0; i<blocknumbers-1; i++) {
|
|
XORblock(src+(blocksize*i),bufblock,bufblock,blocksize);
|
|
diffuse((unsigned char *) bufblock, (unsigned char *) bufblock, blocksize);
|
|
}
|
|
XORblock(src + blocksize * i, bufblock, dst, blocksize);
|
|
|
|
free(bufblock);
|
|
return 0;
|
|
}
|