oox/source/crypto/DocumentDecryption.cxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  *
   9  */
  10
  11 #include <oox/crypto/DocumentDecryption.hxx>
  12
  13 #include <comphelper/sequenceashashmap.hxx>
  14
  15 #include <com/sun/star/beans/NamedValue.hpp>
  16 #include <com/sun/star/io/XSeekable.hpp>
  17 #include <com/sun/star/io/XStream.hpp>
  18 #include <com/sun/star/io/IOException.hpp>
  19 #include <com/sun/star/uno/XComponentContext.hpp>
  20 #include <com/sun/star/packages/XPackageEncryption.hpp>
  21 #include <oox/ole/olestorage.hxx>
  22 #include <oox/helper/binaryinputstream.hxx>
  23
  24 #include <sal/log.hxx>
  25 #include <utility>
  26
  27 namespace
  28 {
  29 void lcl_getListOfStreams(oox::StorageBase* pStorage, std::vector<OUString>& rElementNames)
  30 {
  31     std::vector<OUString> oElementNames;
  32     pStorage->getElementNames(oElementNames);
  33     for (const auto& sName : oElementNames)
  34     {
  35         oox::StorageRef rSubStorage = pStorage->openSubStorage(sName, false);
  36         if (rSubStorage && rSubStorage->isStorage())
  37         {
  38             lcl_getListOfStreams(rSubStorage.get(), rElementNames);
  39         }
  40         else
  41         {
  42             if (pStorage->isRootStorage())
  43                 rElementNames.push_back(sName);
  44             else
  45                 rElementNames.push_back(pStorage->getPath() + "/" + sName);
  46         }
  47     }
  48 }
  49 }
  50
  51 namespace oox::crypto
  52 {
  53 using namespace css;
  54
  55 DocumentDecryption::DocumentDecryption(css::uno::Reference<css::uno::XComponentContext> xContext,
  56                                        oox::ole::OleStorage& rOleStorage)
  57     : mxContext(std::move(xContext))
  58     , mrOleStorage(rOleStorage)
  59 {
  60     // Get OLE streams into sequences for later use in CryptoEngine
  61     std::vector<OUString> aStreamNames;
  62     lcl_getListOfStreams(&mrOleStorage, aStreamNames);
  63
  64     comphelper::SequenceAsHashMap aStreamsData;
  65     for (const auto& sStreamName : aStreamNames)
  66     {
  67         uno::Reference<io::XInputStream> xStream = mrOleStorage.openInputStream(sStreamName);
  68         if (!xStream.is())
  69             throw io::IOException("Cannot open OLE input stream for " + sStreamName + "!");
  70
  71         BinaryXInputStream aBinaryInputStream(xStream, true);
  72
  73         css::uno::Sequence<sal_Int8> oData;
  74         sal_Int32 nStreamSize = aBinaryInputStream.size();
  75         sal_Int32 nReadBytes = aBinaryInputStream.readData(oData, nStreamSize);
  76
  77         if (nStreamSize != nReadBytes)
  78         {
  79             SAL_WARN("oox", "OLE stream invalid content");
  80             throw io::IOException("OLE stream invalid content for " + sStreamName + "!");
  81         }
  82
  83         aStreamsData[sStreamName] <<= oData;
  84     }
  85     maStreamsSequence = aStreamsData.getAsConstNamedValueList();
  86 }
  87
  88 bool DocumentDecryption::generateEncryptionKey(const OUString& rPassword)
  89 {
  90     if (mxPackageEncryption.is())
  91         return mxPackageEncryption->generateEncryptionKey(rPassword);
  92     return false;
  93 }
  94
  95 bool DocumentDecryption::readEncryptionInfo()
  96 {
  97     if (!mrOleStorage.isStorage())
  98         return false;
  99
 100     // Read 0x6DataSpaces/DataSpaceMap
 101     uno::Reference<io::XInputStream> xDataSpaceMap
 102         = mrOleStorage.openInputStream(u"\006DataSpaces/DataSpaceMap"_ustr);
 103     OUString sDataSpaceName;
 104
 105     if (xDataSpaceMap.is())
 106     {
 107         bool bBroken = false;
 108
 109         BinaryXInputStream aDataSpaceStream(xDataSpaceMap, true);
 110         sal_uInt32 aHeaderLength = aDataSpaceStream.readuInt32();
 111         SAL_WARN_IF(aHeaderLength != 8, "oox",
 112                     "DataSpaceMap length != 8 is not supported. Some content may be skipped");
 113         sal_uInt32 aEntryCount = aDataSpaceStream.readuInt32();
 114         SAL_WARN_IF(aEntryCount != 1, "oox",
 115                     "DataSpaceMap contains more than one entry. Some content may be skipped");
 116
 117         // Read each DataSpaceMapEntry (MS-OFFCRYPTO 2.1.6.1)
 118         for (sal_uInt32 i = 0; i < aEntryCount && !bBroken; i++)
 119         {
 120             // entryLen unused for the moment
 121             aDataSpaceStream.skip(sizeof(sal_uInt32));
 122
 123             // Read each DataSpaceReferenceComponent (MS-OFFCRYPTO 2.1.6.2)
 124             sal_uInt32 aReferenceComponentCount = aDataSpaceStream.readuInt32();
 125             for (sal_uInt32 j = 0; j < aReferenceComponentCount && !bBroken; j++)
 126             {
 127                 // Read next reference component
 128                 // refComponentType unused for the moment
 129                 aDataSpaceStream.skip(sizeof(sal_uInt32));
 130                 sal_uInt32 aReferenceComponentNameLength = aDataSpaceStream.readuInt32();
 131                 // sReferenceComponentName unused for the moment
 132                 if (aDataSpaceStream.getRemaining() < aReferenceComponentNameLength)
 133                 {
 134                     bBroken = true;
 135                     break;
 136                 }
 137                 aDataSpaceStream.readUnicodeArray(aReferenceComponentNameLength / 2);
 138                 aDataSpaceStream.skip((4 - (aReferenceComponentNameLength & 3))
 139                                       & 3); // Skip padding
 140
 141                 bBroken |= aDataSpaceStream.isEof();
 142             }
 143
 144             sal_uInt32 aDataSpaceNameLength = aDataSpaceStream.readuInt32();
 145             if (aDataSpaceStream.getRemaining() < aDataSpaceNameLength)
 146             {
 147                 bBroken = true;
 148                 break;
 149             }
 150             sDataSpaceName = aDataSpaceStream.readUnicodeArray(aDataSpaceNameLength / 2);
 151             aDataSpaceStream.skip((4 - (aDataSpaceNameLength & 3)) & 3); // Skip padding
 152
 153             bBroken |= aDataSpaceStream.isEof();
 154         }
 155
 156         if (bBroken)
 157         {
 158             SAL_WARN("oox", "EOF on parsing DataSpaceMapEntry table");
 159             return false;
 160         }
 161     }
 162     else
 163     {
 164         // Fallback for documents generated by LO: they sometimes do not have all
 165         // required by MS-OFFCRYPTO specification streams (0x6DataSpaces/DataSpaceMap and others)
 166         SAL_WARN("oox", "Encrypted package does not contain DataSpaceMap");
 167         sDataSpaceName = "StrongEncryptionDataSpace";
 168     }
 169
 170     uno::Sequence<uno::Any> aArguments;
 171     mxPackageEncryption.set(
 172         mxContext->getServiceManager()->createInstanceWithArgumentsAndContext(
 173             "com.sun.star.comp.oox.crypto." + sDataSpaceName, aArguments, mxContext),
 174         css::uno::UNO_QUERY);
 175
 176     if (!mxPackageEncryption.is())
 177     {
 178         // we do not know how to decrypt this document
 179         return false;
 180     }
 181
 182     return mxPackageEncryption->readEncryptionInfo(maStreamsSequence);
 183 }
 184
 185 uno::Sequence<beans::NamedValue> DocumentDecryption::createEncryptionData(const OUString& rPassword)
 186 {
 187     if (!mxPackageEncryption.is())
 188         return uno::Sequence<beans::NamedValue>();
 189
 190     return mxPackageEncryption->createEncryptionData(rPassword);
 191 }
 192
 193 bool DocumentDecryption::decrypt(const uno::Reference<io::XStream>& xDocumentStream)
 194 {
 195     bool bResult = false;
 196
 197     if (!mrOleStorage.isStorage())
 198         return false;
 199
 200     if (!mxPackageEncryption.is())
 201         return false;
 202
 203     // open the required input streams in the encrypted package
 204     uno::Reference<io::XInputStream> xEncryptedPackage
 205         = mrOleStorage.openInputStream(u"EncryptedPackage"_ustr);
 206
 207     // create temporary file for unencrypted package
 208     uno::Reference<io::XOutputStream> xDecryptedPackage = xDocumentStream->getOutputStream();
 209
 210     bResult = mxPackageEncryption->decrypt(xEncryptedPackage, xDecryptedPackage);
 211
 212     css::uno::Reference<io::XSeekable> xSeekable(xDecryptedPackage, css::uno::UNO_QUERY);
 213     xSeekable->seek(0);
 214
 215     if (bResult)
 216         return mxPackageEncryption->checkDataIntegrity();
 217
 218     return bResult;
 219 }
 220
 221 } // namespace oox::crypto
 222
 223 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */