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/*
File: file_dovecot.c
Copyright (C) 2021 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_dovecot)
#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"
/*@ requires valid_register_header_check(file_stat); */
static void register_header_check_dovecot(file_stat_t *file_stat);
const file_hint_t file_hint_dovecot= {
.extension="dovecot",
.description="dovecot encrypted files",
.max_filesize=PHOTOREC_MAX_FILE_SIZE,
.recover=1,
.enable_by_default=0,
.register_header_check=®ister_header_check_dovecot
};
/*@
@ requires file_recovery->data_check==&data_check_dovecot2;
@ requires valid_data_check_param(buffer, buffer_size, file_recovery);
@ terminates \true;
@ ensures valid_data_check_result(\result, file_recovery);
@ ensures \result == DC_CONTINUE || \result == DC_ERROR;
@ assigns file_recovery->data_check;
@*/
static data_check_t data_check_dovecot2(const unsigned char *buffer, const unsigned int buffer_size, file_recovery_t *file_recovery)
{
/*@ assert file_recovery->calculated_file_size <= PHOTOREC_MAX_FILE_SIZE; */
/*@ assert file_recovery->file_size <= PHOTOREC_MAX_FILE_SIZE; */
if(file_recovery->calculated_file_size + buffer_size/2 >= file_recovery->file_size &&
file_recovery->calculated_file_size + 2 <= file_recovery->file_size + buffer_size/2)
{
const unsigned int i=file_recovery->calculated_file_size + buffer_size/2 - file_recovery->file_size;
/*@ assert 0 <= i <= buffer_size - 2; */
if(buffer[i] == 0 && buffer[i+1] == 0)
{
return DC_ERROR;
}
file_recovery->data_check=NULL;
}
return DC_CONTINUE;
}
/*@
@ requires file_recovery->data_check==&data_check_dovecot;
@ requires valid_data_check_param(buffer, buffer_size, file_recovery);
@ terminates \true;
@ ensures valid_data_check_result(\result, file_recovery);
@ ensures \result == DC_CONTINUE || \result == DC_ERROR;
@ assigns file_recovery->calculated_file_size, file_recovery->data_check;
@*/
static data_check_t data_check_dovecot(const unsigned char *buffer, const unsigned int buffer_size, file_recovery_t *file_recovery)
{
unsigned int i;
/*@
@ loop assigns i;
@ loop variant buffer_size - i;
@*/
for(i=buffer_size/2;
i<buffer_size && file_recovery->calculated_file_size+i <= 0x14000;
i++)
{
if(buffer[i]!='\0')
return DC_ERROR;
}
if(file_recovery->calculated_file_size+buffer_size/2 < 0x14000)
{
file_recovery->calculated_file_size+=buffer_size/2;
return DC_CONTINUE;
}
file_recovery->calculated_file_size=0x14000;
file_recovery->data_check=data_check_dovecot2;
return data_check_dovecot2(buffer, buffer_size, file_recovery);
}
/*@
@ 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);
@*/
static int header_check_dovecot(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)
{
if(file_recovery->data_check==&data_check_dovecot)
return 0;
reset_file_recovery(file_recovery_new);
file_recovery_new->extension=file_hint_dovecot.extension;
file_recovery_new->data_check=&data_check_dovecot;
file_recovery_new->min_filesize=0x14000;
return 1;
}
static void register_header_check_dovecot(file_stat_t *file_stat)
{
static const unsigned char dovecot_header[0x30]= {
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0
};
register_header_check(0, dovecot_header, sizeof(dovecot_header), &header_check_dovecot, file_stat);
}
#endif
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