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/*

    File: file_vmdk.c

    Copyright (C) 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_vmdk)
#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"

/*@ requires \valid(file_stat); */
static void register_header_check_vmdk(file_stat_t *file_stat);
#define MAX_FILE_SIZE_VMDK (uint64_t)2048 * 1024 * 1024 * 1024

const file_hint_t file_hint_vmdk = {
  .extension = "vmdk",
  .description = "VMWare",
  .max_filesize = MAX_FILE_SIZE_VMDK,
  .recover = 1,
  .enable_by_default = 1,
  .register_header_check = &register_header_check_vmdk
};

/* http://www.vmware.com/app/vmdk/?src=vmdk */
typedef struct
{
  uint32_t magic;
  uint32_t version;
  uint32_t flags;
  uint32_t disk_sectors;
  uint32_t granularity;
  uint32_t l1dir_offset;
  uint32_t l1dir_size;
  uint32_t file_sectors;
  uint32_t cylinders;
  uint32_t heads;
  uint32_t sectors_per_track;
} VMDK3Header;

typedef struct
{
  uint32_t magic;
  uint32_t version;
  uint32_t flags;
  uint64_t capacity;
  uint64_t granularity;
  uint64_t desc_offset;
  uint64_t desc_size;
  uint32_t num_gtes_per_gte;
  uint64_t rgd_offset;
  uint64_t gd_offset;
  uint64_t grain_offset;
  char filler[1];
  char check_bytes[4];
} __attribute__((gcc_struct, __packed__)) VMDK4Header;

/*@
  @ requires buffer_size >= sizeof(VMDK3Header);
  @ requires \valid_read(buffer+(0..buffer_size-1));
  @ requires valid_file_recovery(file_recovery);
  @ requires \valid(file_recovery_new);
  @ requires file_recovery_new->blocksize > 0;
  @ requires separation: \separated(&file_hint_vmdk, buffer+(..), file_recovery, file_recovery_new);
  @ ensures  \result!=0 ==> valid_file_recovery(file_recovery_new);
  @ assigns  *file_recovery_new;
  @*/
static int header_check_vmdk3(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 VMDK3Header *hdr = (const VMDK3Header *)buffer;
  const unsigned int cluster_sectors = le32(hdr->granularity);
  if(cluster_sectors == 0 || cluster_sectors > 0x200000)
    return 0;
  reset_file_recovery(file_recovery_new);
#ifdef DJGPP
  file_recovery_new->extension = "vmd";
#else
  file_recovery_new->extension = file_hint_vmdk.extension;
#endif
  file_recovery_new->min_filesize = 512;
  return 1;
}

/*@
  @ requires buffer_size >= sizeof(VMDK4Header);
  @ requires \valid_read(buffer+(0..buffer_size-1));
  @ requires valid_file_recovery(file_recovery);
  @ requires \valid(file_recovery_new);
  @ requires file_recovery_new->blocksize > 0;
  @ requires separation: \separated(&file_hint_vmdk, buffer+(..), file_recovery, file_recovery_new);
  @ ensures  \result!=0 ==> valid_file_recovery(file_recovery_new);
  @ assigns  *file_recovery_new;
  @*/
static int header_check_vmdk4(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 VMDK4Header *hdr = (const VMDK4Header *)buffer;
  const uint64_t cluster_sectors = le64(hdr->granularity);
  const unsigned int num_gtes_per_gte = le32(hdr->num_gtes_per_gte);
  if(cluster_sectors == 0 || cluster_sectors > 0x200000)
    return 0;
  if(num_gtes_per_gte == 0 || num_gtes_per_gte > 512)
    return 0;
  if(le64(hdr->grain_offset) > MAX_FILE_SIZE_VMDK)
    return 0;
  reset_file_recovery(file_recovery_new);
#ifdef DJGPP
  file_recovery_new->extension = "vmd";
#else
  file_recovery_new->extension = file_hint_vmdk.extension;
#endif
  file_recovery_new->min_filesize = td_max((uint64_t)512, (uint64_t)512 * le64(hdr->grain_offset));
  return 1;
}

static void register_header_check_vmdk(file_stat_t *file_stat)
{
  static const unsigned char vmdk_header3_1[8] = { 'C', 'O', 'W', 'D', 0x01, 0x00, 0x00, 0x00 };
  static const unsigned char vmdk_header4_1[8] = { 'K', 'D', 'M', 'V', 0x01, 0x00, 0x00, 0x00 };
  static const unsigned char vmdk_header4_2[8] = { 'K', 'D', 'M', 'V', 0x02, 0x00, 0x00, 0x00 };
  static const unsigned char vmdk_header4_3[8] = { 'K', 'D', 'M', 'V', 0x03, 0x00, 0x00, 0x00 };
  register_header_check(0, vmdk_header3_1, sizeof(vmdk_header3_1), &header_check_vmdk3, file_stat);
  register_header_check(0, vmdk_header4_1, sizeof(vmdk_header4_1), &header_check_vmdk4, file_stat);
  register_header_check(0, vmdk_header4_2, sizeof(vmdk_header4_2), &header_check_vmdk4, file_stat);
  register_header_check(0, vmdk_header4_3, sizeof(vmdk_header4_3), &header_check_vmdk4, file_stat);
}
#endif