/*

    File: file_nk2.c

    Copyright (C) 2009 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_nk2)
#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"
#include "log.h"

/*@
  @ requires valid_register_header_check(file_stat);
  @*/
static void register_header_check_nk2(file_stat_t *file_stat);
#define NK2_MAX_FILESIZE 100*1024*1024

const file_hint_t file_hint_nk2= {
  .extension="nk2",
  .description="Outlook Nickfile",
  .max_filesize=NK2_MAX_FILESIZE,
  .recover=1,
  .enable_by_default=1,
  .register_header_check=&register_header_check_nk2
};

typedef struct {
  uint32_t magic;
  uint32_t magic2;
  uint32_t magic3;
  uint32_t items_count;
} nk2Header;

typedef struct {
  uint32_t entries_count;
} itemHeader;

typedef struct {
  uint16_t value_type;
  uint16_t entry_type;
  uint32_t unk1;
  uint32_t unk2;
  uint32_t unk3;
} entryHeader;

#define	PT_UNSPECIFIED	0x0000
#define	PT_NULL		0x0001
#define	PT_I2		0x0002
#define	PT_LONG		0x0003
#define	PT_R4		0x0004
#define	PT_DOUBLE	0x0005
#define	PT_CURRENCY	0x0006
#define	PT_APPTIME	0x0007
#define	PT_ERROR	0x000a /* means the given attr contains no value */
#define	PT_BOOLEAN	0x000b
#define	PT_OBJECT	0x000d
#define	PT_I8		0x0014
#define	PT_STRING8	0x001e
#define	PT_UNICODE	0x001f
#define	PT_SYSTIME	0x0040
#define	PT_CLSID       	0x0048
#define PT_SRVEID	0x00fb
#define PT_SRESTRICT	0x00fd
#define PT_ACTIONS	0x00fe
#define	PT_BINARY	0x0102

/*@
  @ requires valid_file_check_param(fr);
  @ ensures  valid_file_check_result(fr);
  @ assigns *fr->handle, errno, fr->file_size, fr->offset_error;
  @ assigns Frama_C_entropy_source;
  @*/
static void file_check_nk2_aux(file_recovery_t *fr, const unsigned int entries_count)
{
  unsigned int j;
  /*@
    @ loop assigns *fr->handle, errno, fr->file_size, fr->offset_error;
    @ loop assigns Frama_C_entropy_source;
    @ loop assigns j;
    @ loop variant entries_count - j;
    @*/
  for(j=0; j<entries_count; j++)
  {
    uint64_t size;
    char buf_entryh[sizeof(entryHeader)];
    const entryHeader *entryh=(const entryHeader *)&buf_entryh;
    /*@ assert \valid_read(entryh); */
    if (fread(&buf_entryh, sizeof(entryHeader), 1, fr->handle)!=1)
    {
      fr->offset_error=fr->file_size;
      fr->file_size=0;
      return;
    }
#if defined(__FRAMAC__)
    Frama_C_make_unknown(&buf_entryh, sizeof(entryHeader));
#endif
    switch(le16(entryh->value_type))
    {
      case PT_LONG:
      case PT_BOOLEAN:
      case PT_ERROR:
      case PT_NULL:
	size=0;
	break;
      case PT_UNICODE:
      case PT_BINARY:
	{
	  char buf_entry_size[sizeof(uint32_t)];
	  const uint32_t *entry_size=(const uint32_t *)&buf_entry_size;
	  /*@ assert \valid_read(entry_size); */
	  if (fread(&buf_entry_size, sizeof(uint32_t), 1, fr->handle)!=1)
	  {
	    fr->offset_error=fr->file_size;
	    fr->file_size=0;
	    return;
	  }
#if defined(__FRAMAC__)
	  Frama_C_make_unknown(&buf_entry_size, sizeof(uint32_t));
#endif
	  size=(uint64_t)4+le32(*entry_size);
	}
	break;
      default:
#ifndef DISABLED_FOR_FRAMAC
	log_info("nk2   entry %04x size=? at 0x%llx\n",
	    le16(entryh->value_type),
	    (long long unsigned)fr->file_size);
#endif
	fr->offset_error=fr->file_size;
	fr->file_size=0;
	return;
    }
#ifdef DEBUG_NK2
    {
      log_info("nk2   entry %04x size=%u at 0x%llx\n",
	  le16(entryh->value_type),
	  (unsigned int)size,
	  (long long unsigned)fr->file_size);
      char buffer[2048];
      unsigned int size_to_log=size;
      if(size_to_log>2048)
	size_to_log=2048;
      fread(&buffer, size_to_log, 1, fr->handle);
#if defined(__FRAMAC__)
      Frama_C_make_unknown(buffer, 2048);
#endif
      dump_log(&buffer, size_to_log);
    }
#endif
    fr->file_size+=sizeof(entryHeader);
    if(fr->file_size >= NK2_MAX_FILESIZE)
    {
      fr->file_size=0;
      return;
    }
    if (my_fseek(fr->handle, fr->file_size+size, SEEK_SET) < 0)
    {
      fr->offset_error=fr->file_size;
      fr->file_size=0;
      return;
    }
    fr->file_size+=size;
  }
}

/*@
  @ requires fr->file_check == &file_check_nk2;
  @ requires valid_file_check_param(fr);
  @ ensures  valid_file_check_result(fr);
  @ assigns *fr->handle, errno, fr->file_size, fr->offset_error, fr->offset_ok;
  @ assigns Frama_C_entropy_source;
  @*/
static void file_check_nk2(file_recovery_t *fr)
{
  char buf_nk2h[sizeof(nk2Header)];
  const nk2Header *nk2h=(const nk2Header *)&buf_nk2h;
  unsigned int i;
  /*@ assert \valid(fr); */
  /*@ assert \valid_read(nk2h); */
  fr->file_size = 0;
  fr->offset_error=0;
  fr->offset_ok=0;
  if(my_fseek(fr->handle, 0, SEEK_SET) < 0 ||
      fread(&buf_nk2h, sizeof(nk2Header), 1, fr->handle)!=1)
    return;
#if defined(__FRAMAC__)
  Frama_C_make_unknown(&buf_nk2h, sizeof(nk2Header));
#endif
  fr->file_size+=sizeof(nk2Header);
  /*@ assert fr->file_size > 0; */
#ifdef DEBUG_NK2
  log_info("nk2 item_count=%u\n", (unsigned int)le32(nk2h->items_count));
#endif
  /*@
    @ loop invariant valid_file_check_param(fr);
    @ loop assigns *fr->handle, errno, fr->file_size, fr->offset_error;
    @ loop assigns Frama_C_entropy_source;
    @ loop assigns i;
    @*/
  for(i=0; i<le32(nk2h->items_count); i++)
  {
    char buf_itemh[sizeof(itemHeader)];
    const itemHeader *itemh=(const itemHeader *)&buf_itemh;
    /*@ assert \valid_read(itemh); */
    if(fr->file_size >= NK2_MAX_FILESIZE)
    {
      fr->file_size=0;
      return;
    }
    /*@ assert fr->file_size < NK2_MAX_FILESIZE; */
    if (fread(&buf_itemh, sizeof(itemHeader), 1, fr->handle)!=1)
    {
      fr->offset_error=fr->file_size;
      fr->file_size=0;
      return;
    }
#if defined(__FRAMAC__)
    Frama_C_make_unknown(&buf_itemh, sizeof(buf_itemh));
#endif
    fr->file_size+=sizeof(itemHeader);
#ifdef DEBUG_NK2
    log_info("nk2  entries_count=%u\n", (unsigned int)le32(itemh->entries_count));
#endif
    file_check_nk2_aux(fr, le32(itemh->entries_count));
    if(fr->file_size==0)
      return;
  }
  fr->file_size+=12;
}

/*@
  @ requires separation: \separated(&file_hint_nk2, 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_nk2(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)
{
  reset_file_recovery(file_recovery_new);
  file_recovery_new->extension=file_hint_nk2.extension;
  file_recovery_new->file_check=&file_check_nk2;
  return 1;
}

static void register_header_check_nk2(file_stat_t *file_stat)
{
  static const unsigned char nk2_header[8]=  { 0x0d, 0xf0, 0xad, 0xba, 0x0a, 0x00, 0x00, 0x00 };
  register_header_check(0, nk2_header,  sizeof(nk2_header),  &header_check_nk2, file_stat);
}
#endif