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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: t; c-basic-offset: 4 -*- */
/* libwpd
* Version: MPL 2.0 / LGPLv2.1+
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* Major Contributor(s):
* Copyright (C) 2003 William Lachance (wrlach@gmail.com)
* Copyright (C) 2003 Marc Maurer (uwog@uwog.net)
* Copyright (C) 2006 Fridrich Strba (fridrich.strba@bluewin.ch)
*
* For minor contributions see the git repository.
*
* Alternatively, the contents of this file may be used under the terms
* of the GNU Lesser General Public License Version 2.1 or later
* (LGPLv2.1+), in which case the provisions of the LGPLv2.1+ are
* applicable instead of those above.
*
* For further information visit http://libwpd.sourceforge.net
*/
/* "This product is not manufactured, approved, or supported by
* Corel Corporation or Corel Corporation Limited."
*/
#include "WP1Heuristics.h"
#include "WP1FileStructure.h"
#include "libwpd_internal.h"
#include <limits>
#include <memory>
using namespace libwpd;
WPDPasswordMatch WP1Heuristics::verifyPassword(librevenge::RVNGInputStream *input, const char *password) try
{
if (!password)
return WPD_PASSWORD_MATCH_DONTKNOW;
input->seek(0, librevenge::RVNG_SEEK_SET);
if (readU8(input, nullptr) == 0xFE && readU8(input, nullptr) == 0xFF &&
readU8(input, nullptr) == 0x61 && readU8(input, nullptr) == 0x61)
{
WPXEncryption encryption(password, 6);
if (readU16(input, nullptr, true) == encryption.getCheckSum())
return WPD_PASSWORD_MATCH_OK;
else
return WPD_PASSWORD_MATCH_NONE;
}
else
return WPD_PASSWORD_MATCH_DONTKNOW;
}
catch (...)
{
return WPD_PASSWORD_MATCH_DONTKNOW;
}
WPDConfidence WP1Heuristics::isWP1FileFormat(librevenge::RVNGInputStream *input, const char *password) try
{
input->seek(0, librevenge::RVNG_SEEK_SET);
std::unique_ptr<WPXEncryption> encryption;
if (readU8(input, nullptr) == 0xFE && readU8(input, nullptr) == 0xFF &&
readU8(input, nullptr) == 0x61 && readU8(input, nullptr) == 0x61)
{
if (password)
{
encryption.reset(new WPXEncryption(password, 6));
if (readU16(input, nullptr, true) != encryption->getCheckSum())
return WPD_CONFIDENCE_SUPPORTED_ENCRYPTION;
}
else
{
if (readU16(input,nullptr) != 0x0000)
return WPD_CONFIDENCE_SUPPORTED_ENCRYPTION;
}
}
input->seek(0, librevenge::RVNG_SEEK_SET);
if (password && encryption)
input->seek(6, librevenge::RVNG_SEEK_SET);
int functionGroupCount = 0;
WPD_DEBUG_MSG(("WP1Heuristics::isWP1FileFormat()\n"));
while (!input->isEnd())
{
unsigned char readVal = readU8(input, encryption.get());
WPD_DEBUG_MSG(("WP1Heuristics, Offset 0x%.8x, value 0x%.2x (%c)\n", (unsigned int)input->tell() - 1, readVal, readVal));
if (readVal < (unsigned char)0x20)
{
// line breaks et al, skip
}
else if (readVal >= (unsigned char)0x20 && readVal <= (unsigned char)0x7F)
{
// normal ASCII characters, skip
}
else if (readVal >= (unsigned char)0x80 && readVal <= (unsigned char)0xBF)
{
// single character function codes, skip
functionGroupCount++;
}
else if (readVal >= (unsigned char)0xFF)
{
// special codes that should not be found as separate functions
return WPD_CONFIDENCE_NONE;
}
else
{
// multi character function group
// check that the size constrains are valid, and that every group_member
// is properly closed at the right place
if (WP1_FUNCTION_GROUP_SIZE[readVal-0xC0] == -1)
{
// variable length function group
// We are checking following structure:
// <function code>{function length}...{function length}<function code>
// that we observed in variable length WP1 functions
unsigned functionLength = readU32(input, encryption.get(), true);
if (functionLength == 0 || functionLength > ((std::numeric_limits<unsigned>::max)() / 2))
return WPD_CONFIDENCE_NONE;
WPD_DEBUG_MSG(("WP1Heuristics functionLength = 0x%.8x\n", (unsigned int)functionLength));
input->seek(functionLength, librevenge::RVNG_SEEK_CUR);
unsigned long closingFunctionLength = readU32(input, encryption.get(), true);
WPD_DEBUG_MSG(("WP1Heuristics closingFunctionLength = 0x%.8x\n", (unsigned int)closingFunctionLength));
if (functionLength != closingFunctionLength)
return WPD_CONFIDENCE_NONE;
unsigned char closingGate = 0;
if (!input->isEnd())
{
closingGate = readU8(input, encryption.get());
WPD_DEBUG_MSG(("WP1Heuristics closingGate = 0x%.2x\n", closingGate));
if (closingGate != readVal)
return WPD_CONFIDENCE_NONE;
}
// when passed the complete file, we don't allow for open groups when we've reached EOF
if (input->isEnd() && (closingGate != readVal))
return WPD_CONFIDENCE_NONE;
functionGroupCount++;
}
else
{
// fixed length function group
// seek to the position where the closing gate should be
int res = input->seek(WP1_FUNCTION_GROUP_SIZE[readVal-0xC0]-2, librevenge::RVNG_SEEK_CUR);
// when passed the complete file, we should be able to do that
if (res)
return WPD_CONFIDENCE_NONE;
// read the closing gate
unsigned char readNextVal = readU8(input, encryption.get());
if (readNextVal != readVal)
return WPD_CONFIDENCE_NONE;
functionGroupCount++;
}
}
}
/* When we get here, the document is in a format that we *could* import properly.
However, if we didn't encounter a single WP1 function group) we need to be more carefull:
this would be the case when passed a plaintext file for example, which libwpd is not
supposed to handle. */
if (!functionGroupCount && !encryption)
return WPD_CONFIDENCE_NONE;
return WPD_CONFIDENCE_EXCELLENT;
}
catch (...)
{
return WPD_CONFIDENCE_NONE;
}
/* vim:set shiftwidth=4 softtabstop=4 noexpandtab: */
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