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/*
File: file_dex.c
Copyright (C) 2010 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_dex)
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#include <stdio.h>
#include <ctype.h>
#include "types.h"
#include "filegen.h"
#include "common.h"
/*@ requires valid_register_header_check(file_stat); */
static void register_header_check_dex(file_stat_t *file_stat);
const file_hint_t file_hint_dex= {
.extension="dex",
.description="Dalvik",
.max_filesize=PHOTOREC_MAX_FILE_SIZE,
.recover=1,
.enable_by_default=1,
.register_header_check=®ister_header_check_dex
};
/* More information can be found at https://source.android.com/devices/tech/dalvik/dex-format.html */
struct dex_header
{
unsigned char magic[8];
uint32_t checksum;
unsigned char signature[20];
uint32_t file_size;
uint32_t header_size;
uint32_t endian_tag;
uint32_t link_size;
uint32_t link_off;
uint32_t map_off;
uint32_t strings_ids_size;
uint32_t strings_ids_off;
uint32_t type_ids_size;
uint32_t type_ids_off;
uint32_t proto_ids_size;
uint32_t proto_ids_off;
uint32_t field_ids_size;
uint32_t field_ids_off;
uint32_t method_ids_size;
uint32_t method_ids_off;
uint32_t class_def_size;
uint32_t class_def_off;
uint32_t data_size;
uint32_t data_off;
} __attribute__ ((gcc_struct, __packed__));
/*@
@ requires buffer_size >= sizeof(struct dex_header);
@ requires separation: \separated(&file_hint_dex, buffer+(..), file_recovery, file_recovery_new);
@ requires valid_header_check_param(buffer, buffer_size, safe_header_only, file_recovery, file_recovery_new);
@ ensures valid_header_check_result(\result, file_recovery_new);
@ assigns *file_recovery_new;
@*/
static int header_check_dex(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 dex_header *dex=(const struct dex_header*)buffer;
if(!isdigit(buffer[4]) || !isdigit(buffer[5]) || !isdigit(buffer[6]) || buffer[7]!=0x00)
return 0;
if(le32(dex->header_size) < 0x28)
return 0;
if(le32(dex->header_size) >= le32(dex->file_size))
return 0;
reset_file_recovery(file_recovery_new);
file_recovery_new->extension=file_hint_dex.extension;
file_recovery_new->calculated_file_size=le32(dex->file_size);
file_recovery_new->data_check=&data_check_size;
file_recovery_new->file_check=&file_check_size;
return 1;
}
static void register_header_check_dex(file_stat_t *file_stat)
{
static const unsigned char dex_header[4]= {'d','e','x','\n'};
register_header_check(0, dex_header,sizeof(dex_header), &header_check_dex, file_stat);
}
#endif
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