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/*

    File: file_woff.c

    Copyright (C) 2014 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_woff)
#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_woff(file_stat_t *file_stat);

const file_hint_t file_hint_woff = {
  .extension = "woff",
  .description = "Web Open Font Format",
  .max_filesize = PHOTOREC_MAX_FILE_SIZE,
  .recover = 1,
  .enable_by_default = 1,
  .register_header_check = &register_header_check_woff
};

struct WOFFHeader
{
  uint32_t signature;
  uint32_t flavor;
  uint32_t length;
  uint16_t numTables;
  uint16_t reserved;
  uint32_t totalSfntSize;
  uint16_t majorVersion;
  uint16_t minorVersion;
  uint32_t metaOffset;
  uint32_t metaLength;
  uint32_t metaOrigLength;
  uint32_t privOffset;
  uint32_t privLength;
} __attribute__((gcc_struct, __packed__));

/*@
  @ requires buffer_size >= sizeof(struct WOFFHeader);
  @ 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_woff, buffer+(..), file_recovery, file_recovery_new);
  @ ensures  \result!=0 ==> valid_file_recovery(file_recovery_new);
  @ assigns  *file_recovery_new;
  @*/
static int header_check_woff(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 WOFFHeader *woff = (const struct WOFFHeader *)buffer;
  const uint32_t length = be32(woff->length);
  const uint32_t metaLength = be32(woff->metaLength);
  const uint32_t metaOffset = be32(woff->metaOffset);
  const uint32_t privLength = be32(woff->privLength);
  const uint32_t privOffset = be32(woff->privOffset);
  if(length < sizeof(struct WOFFHeader))
    return 0;
  if(metaOffset > 0 && metaOffset < sizeof(struct WOFFHeader))
    return 0;
  if(privOffset > 0 && privOffset < sizeof(struct WOFFHeader))
    return 0;
  if((uint64_t)metaOffset + metaLength > length || (uint64_t)privOffset + privLength > length)
    return 0;
  if(woff->reserved != 0)
    return 0;
  reset_file_recovery(file_recovery_new);
  file_recovery_new->extension = file_hint_woff.extension;
  file_recovery_new->calculated_file_size = length;
  file_recovery_new->data_check = &data_check_size;
  file_recovery_new->file_check = &file_check_size;
  return 1;
}

static void register_header_check_woff(file_stat_t *file_stat)
{
  register_header_check(0, "wOFF", 4, &header_check_woff, file_stat);
}
#endif