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/*
File: file_axx.c
Copyright (C) 2012 Christophe GRENIER <grenier@cgsecurity.org>
This software 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.
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 General Public License along
with this program; if not, write the Free Software Foundation, Inc., 51
Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#if !defined(SINGLE_FORMAT) || defined(SINGLE_FORMAT_axx)
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#include <stdio.h>
#include "types.h"
#include "filegen.h"
#include "common.h"
#include "log.h"
/*@ requires valid_register_header_check(file_stat); */
static void register_header_check_axx(file_stat_t *file_stat);
const file_hint_t file_hint_axx= {
.extension="axx",
.description="AxCrypt",
.max_filesize=PHOTOREC_MAX_FILE_SIZE,
.recover=1,
.enable_by_default=1,
.register_header_check=®ister_header_check_axx
};
struct SHeader
{
uint32_t aoLength;
uint8_t oType;
} __attribute__ ((gcc_struct, __packed__));
/*@
@ requires fr->file_check == &file_check_axx;
@ requires valid_file_check_param(fr);
@ ensures valid_file_check_result(fr);
@ assigns *fr->handle, errno, fr->file_size;
@ assigns Frama_C_entropy_source;
@*/
static void file_check_axx(file_recovery_t *fr)
{
uint64_t offset=0x10;
/*@
@ loop assigns *fr->handle, errno, fr->file_size;
@ loop assigns offset, Frama_C_entropy_source;
@ loop variant 0x8000000000000000 - offset;
@ */
while(offset < 0x8000000000000000)
{
char buffer[sizeof(struct SHeader)];
const struct SHeader *header=(const struct SHeader *)&buffer;
unsigned int len;
if(my_fseek(fr->handle, offset, SEEK_SET) < 0)
return ;
if (fread(&buffer, sizeof(buffer), 1, fr->handle)!=1)
return ;
#if defined(__FRAMAC__)
Frama_C_make_unknown(&buffer, sizeof(buffer));
#endif
len=le32(header->aoLength);
#ifdef DEBUG_AAX
log_info("axx 0x%llx 0x%x 0x%x/%d\n", (long long int)offset, len, header->oType, header->oType);
#endif
if(len<5)
return ;
offset+=len;
if(offset >= 0x8000000000000000)
break;
if(header->oType==63) // eData
{
char buf[sizeof(uint64_t)];
const uint64_t *fsize_ptr=(const uint64_t *)&buf;
uint64_t fsize;
if(len!=13)
return ;
if (fread(&buf, sizeof(buf), 1, fr->handle)!=1)
return ;
#if defined(__FRAMAC__)
Frama_C_make_unknown(&buf, sizeof(buf));
#endif
fsize=le64(*fsize_ptr);
if(fsize >= 0x8000000000000000)
break;
offset+=fsize;
fr->file_size=(fr->file_size < offset ? 0 : offset);
return ;
}
}
fr->file_size=0;
}
/*@
@ requires buffer_size > 0x25+sizeof(struct SHeader);
@ requires separation: \separated(&file_hint_axx, buffer+(..), file_recovery, file_recovery_new);
@ requires valid_header_check_param(buffer, buffer_size, safe_header_only, file_recovery, file_recovery_new);
@ terminates \true;
@ ensures valid_header_check_result(\result, file_recovery_new);
@ assigns *file_recovery_new;
@*/
static int header_check_axx(const unsigned char *buffer, const unsigned int buffer_size, const unsigned int safe_header_only, const file_recovery_t *file_recovery, file_recovery_t *file_recovery_new)
{
const struct SHeader *header=(const struct SHeader *)&buffer[0x10+0x15];
if(le32(header->aoLength) < 5)
return 0;
reset_file_recovery(file_recovery_new);
file_recovery_new->extension=file_hint_axx.extension;
file_recovery_new->file_check=&file_check_axx;
file_recovery_new->min_filesize=(uint64_t)0x25+le32(header->aoLength);
return 1;
}
static void register_header_check_axx(file_stat_t *file_stat)
{
// guidAxCryptFileIdInverse (32 bytes) + length (4) + ePreamble=2
static const unsigned char axx_header[0x15]= {
0xc0, 0xb9, 0x07, 0x2e, 0x4f, 0x93, 0xf1, 0x46,
0xa0, 0x15, 0x79, 0x2c, 0xa1, 0xd9, 0xe8, 0x21,
0x15, 0x00, 0x00, 0x00, 0x02
};
register_header_check(0, axx_header, sizeof(axx_header), &header_check_axx, file_stat);
}
#endif
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