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/*
File: file_ext2_sb.c
Copyright (C) 1998-2005,2007 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_ext2_sb)
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#include <stdio.h>
#include "types.h"
#include "common.h"
#include "ext2_common.h"
#include "filegen.h"
#include "log.h"
/*@ requires valid_register_header_check(file_stat); */
static void register_header_check_ext2_sb(file_stat_t *file_stat);
const file_hint_t file_hint_ext2_sb= {
.extension="ext",
.description="ext2/ext3/ext4 Superblock",
.max_filesize=PHOTOREC_MAX_FILE_SIZE,
.recover=0,
.enable_by_default=1,
.register_header_check=®ister_header_check_ext2_sb
};
/*@
@ requires file_recovery->file_rename==&file_rename_ext;
@ requires valid_file_rename_param(file_recovery);
@ ensures valid_file_rename_result(file_recovery);
@*/
static void file_rename_ext(file_recovery_t *file_recovery)
{
unsigned char buffer[1024];
char buffer_cluster[32];
FILE *file;
const struct ext2_super_block *sb=(const struct ext2_super_block *)&buffer;
int buffer_size;
unsigned long int block_nr;
if((file=fopen(file_recovery->filename, "rb"))==NULL)
return;
buffer_size=fread(buffer, 1, sizeof(buffer), file);
fclose(file);
if(buffer_size!=sizeof(buffer))
return;
/*@ assert buffer_size == sizeof(buffer); */
#if defined(__FRAMAC__)
Frama_C_make_unknown(buffer, sizeof(buffer));
#endif
/*@ assert \initialized(buffer + (0 .. sizeof(buffer)-1)); */
block_nr=(unsigned long int)le32(sb->s_first_data_block) + (unsigned long int)le16(sb->s_block_group_nr)*le32(sb->s_blocks_per_group);
sprintf(buffer_cluster, "sb_%lu", block_nr);
#if defined(DISABLED_FOR_FRAMAC)
buffer_cluster[sizeof(buffer_cluster)-1]='\0';
#endif
file_rename(file_recovery, buffer_cluster, strlen(buffer_cluster), 0, NULL, 1);
}
/*@
@ requires buffer_size >= sizeof(struct ext2_super_block);
@ requires separation: \separated(&file_hint_ext2_sb, 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_ext2_sb(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 ext2_super_block *sb=(const struct ext2_super_block *)buffer;
if(test_EXT2(sb, NULL)!=0)
return 0;
/*@ assert le32(sb->s_log_block_size) <= 6; */
reset_file_recovery(file_recovery_new);
file_recovery_new->extension=file_hint_ext2_sb.extension;
file_recovery_new->file_size=(uint64_t)EXT2_MIN_BLOCK_SIZE<<le32(sb->s_log_block_size);
file_recovery_new->data_check=&data_check_size;
file_recovery_new->file_check=&file_check_size;
file_recovery_new->file_rename=&file_rename_ext;
return 1;
}
/*@
@ requires file_recovery->data_check==&data_check_extdir;
@ requires valid_data_check_param(buffer, buffer_size, file_recovery);
@ ensures valid_data_check_result(\result, file_recovery);
@ assigns file_recovery->calculated_file_size;
@*/
static data_check_t data_check_extdir(const unsigned char *buffer, const unsigned int buffer_size, file_recovery_t *file_recovery)
{
/* Save only one block */
file_recovery->calculated_file_size=buffer_size/2;
return DC_STOP;
}
/*@
@ requires valid_file_rename_param(file_recovery);
@ ensures valid_file_rename_result(file_recovery);
@*/
static void file_rename_extdir(file_recovery_t *file_recovery)
{
unsigned char buffer[512];
char buffer_cluster[32];
FILE *file;
int buffer_size;
const uint32_t *inode=(const uint32_t *)&buffer[0];
if((file=fopen(file_recovery->filename, "rb"))==NULL)
return;
buffer_size=fread(buffer, 1, sizeof(buffer), file);
fclose(file);
if(buffer_size!=sizeof(buffer))
return;
/*@ assert buffer_size == sizeof(buffer); */
#if defined(__FRAMAC__)
Frama_C_make_unknown(buffer, sizeof(buffer));
#endif
/*@ assert \initialized(buffer + (0 .. sizeof(buffer)-1)); */
sprintf(buffer_cluster, "inode_%u", (unsigned int)le32(*inode));
#if defined(DISABLED_FOR_FRAMAC)
buffer_cluster[sizeof(buffer_cluster)-1]='\0';
#endif
file_rename(file_recovery, buffer_cluster, strlen(buffer_cluster), 0, NULL, 1);
}
/*@
@ requires buffer_size >= sizeof(struct ext2_super_block);
@ requires separation: \separated(&file_hint_ext2_sb, 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_ext2_dir(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)
{
static const unsigned char ext2_ll_dir2[6]= { 0x02, 0x02, '.', '.', 0x00, 0x00};
if(memcmp(&buffer[0x12], ext2_ll_dir2, sizeof(ext2_ll_dir2))!=0)
return 0;
reset_file_recovery(file_recovery_new);
file_recovery_new->extension=file_hint_ext2_sb.extension;
file_recovery_new->data_check=&data_check_extdir;
file_recovery_new->file_check=&file_check_size;
file_recovery_new->file_rename=&file_rename_extdir;
/*@ assert valid_file_recovery(file_recovery_new); */
return 1;
}
static void register_header_check_ext2_sb(file_stat_t *file_stat)
{
static const unsigned char ext2_sb_header[2]= {0x53, 0xEF};
static const unsigned char ext2_ll_dir1[8]= {0x0c, 0x00, 0x01, 0x02, '.', 0x00, 0x00, 0x00};
register_header_check(0x38, ext2_sb_header, sizeof(ext2_sb_header), &header_check_ext2_sb, file_stat);
register_header_check(0x4, ext2_ll_dir1, sizeof(ext2_ll_dir1), &header_check_ext2_dir, file_stat);
}
#endif
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