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/*
File: file_hdf.c
Copyright (C) 2011 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_hdf)
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#include <stdio.h>
#include "types.h"
#include "filegen.h"
#include "common.h"
#ifdef DEBUG_HDF
#include "log.h"
#endif
/*@ requires valid_register_header_check(file_stat); */
static void register_header_check_hdf(file_stat_t *file_stat);
const file_hint_t file_hint_hdf= {
.extension="hdf",
.description="Hierarchical Data Format 4",
.max_filesize=PHOTOREC_MAX_SIZE_32,
.recover=1,
.enable_by_default=1,
.register_header_check=®ister_header_check_hdf
};
struct ddh_struct
{
uint16_t size;
uint32_t next;
} __attribute__ ((gcc_struct, __packed__));
struct dd_struct
{
uint16_t tag;
uint16_t ref;
uint32_t offset;
uint32_t length;
} __attribute__ ((gcc_struct, __packed__));
/*@
@ requires \valid(handle);
@ requires \valid(dd_buf + (0 .. 65536 * sizeof(struct dd_struct)-1));
@ requires \separated(handle, dd_buf + (..), &errno, &Frama_C_entropy_source);
@ assigns *(dd_buf + (0 .. 65536 * sizeof(struct dd_struct)-1));
@ assigns Frama_C_entropy_source;
@ assigns *handle, errno;
@*/
static uint64_t file_check_hdf_aux(FILE *handle, char *dd_buf)
{
uint64_t file_size=0;
uint64_t offset_old;
uint64_t offset=4;
const struct dd_struct *dd=(const struct dd_struct *)dd_buf;
/*@
@ loop assigns file_size, offset_old, offset;
@ loop assigns *(dd_buf + (0 .. 65536 * sizeof(struct dd_struct)-1));
@ loop assigns Frama_C_entropy_source;
@ loop assigns *handle, errno;
@*/
do
{
char ddh_buf[sizeof(struct ddh_struct)];
const struct ddh_struct *ddh=(const struct ddh_struct *)&ddh_buf;
unsigned int i;
unsigned int size;
if(my_fseek(handle, offset, SEEK_SET) < 0 ||
fread(&ddh_buf, sizeof(ddh_buf), 1, handle) !=1)
{
return 0;
}
#ifdef __FRAMAC__
Frama_C_make_unknown(&ddh_buf, sizeof(ddh_buf));
#endif
size=be16(ddh->size);
/*@ assert 0 <= size < 65536; */
if(size==0 ||
fread(dd_buf, sizeof(struct dd_struct)*size, 1, handle) !=1)
{
return 0;
}
#ifdef __FRAMAC__
Frama_C_make_unknown(dd_buf, sizeof(struct dd_struct)*size);
#endif
if(file_size < offset + sizeof(struct dd_struct) * size)
file_size = offset + sizeof(struct dd_struct) * size;
#ifdef DEBUG_HDF
log_info("size=%u next=%lu\n", size, be32(ddh->next));
#endif
/*@
@ loop invariant 0 <= i <= size;
@ loop assigns i, file_size;
@ loop variant size - i;
@*/
for(i=0; i < size; i++)
{
const struct dd_struct *p=&dd[i];
const unsigned int p_offset=be32(p->offset);
const unsigned int p_length=be32(p->length);
#ifdef DEBUG_HDF
log_info("tag=0x%04x, ref=%u, offset=%lu, length=%lu\n",
be16(p->tag), be16(p->ref), p_offset, p_length);
#endif
if(p_offset!=0xffffffff &&
file_size < (uint64_t)p_offset + (uint64_t)p_length)
file_size = (uint64_t)p_offset + (uint64_t)p_length;
}
offset_old=offset;
offset=be32(ddh->next);
} while(offset > offset_old);
file_size++;
return file_size;
}
/*@
@ requires \separated(file_recovery, file_recovery->handle, &errno, &Frama_C_entropy_source, &__fc_heap_status);
@ requires valid_file_check_param(file_recovery);
@ ensures valid_file_check_result(file_recovery);
@*/
static void file_check_hdf(file_recovery_t *file_recovery)
{
uint64_t file_size;
char *dd;
dd=(char *)MALLOC(sizeof(struct dd_struct)*65536);
file_size = file_check_hdf_aux(file_recovery->handle, dd);
free(dd);
#ifdef DEBUG_HDF
log_info("file_size %llu\n", (long long unsigned)file_size);
#endif
if(file_recovery->file_size < file_size || file_size==0)
file_recovery->file_size=0;
else
file_recovery->file_size = file_size;
}
/*@
@ requires buffer_size >= sizeof(struct ddh_struct);
@ requires separation: \separated(&file_hint_hdf, 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_hdf(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 ddh_struct *ddh=(const struct ddh_struct *)&buffer[4];
if(be16(ddh->size)==0)
return 0;
reset_file_recovery(file_recovery_new);
file_recovery_new->extension=file_hint_hdf.extension;
file_recovery_new->file_check=&file_check_hdf;
return 1;
}
static void register_header_check_hdf(file_stat_t *file_stat)
{
static const unsigned char hdf_header[4]= { 0x0e, 0x03, 0x13, 0x01};
register_header_check(0, hdf_header, sizeof(hdf_header), &header_check_hdf, file_stat);
}
#endif
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