Files
core/PdfReader/Src/SecurityHandler.cpp
ElenaSubbotina 274c000ce7 fix PdfReader
2018-09-20 11:35:30 +03:00

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/*
* (c) Copyright Ascensio System SIA 2010-2018
*
* This program is a free software product. You can redistribute it and/or
* modify it under the terms of the GNU Affero General Public License (AGPL)
* version 3 as published by the Free Software Foundation. In accordance with
* Section 7(a) of the GNU AGPL its Section 15 shall be amended to the effect
* that Ascensio System SIA expressly excludes the warranty of non-infringement
* of any third-party rights.
*
* This program is distributed WITHOUT ANY WARRANTY; without even the implied
* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. For
* details, see the GNU AGPL at: http://www.gnu.org/licenses/agpl-3.0.html
*
* You can contact Ascensio System SIA at Lubanas st. 125a-25, Riga, Latvia,
* EU, LV-1021.
*
* The interactive user interfaces in modified source and object code versions
* of the Program must display Appropriate Legal Notices, as required under
* Section 5 of the GNU AGPL version 3.
*
* Pursuant to Section 7(b) of the License you must retain the original Product
* logo when distributing the program. Pursuant to Section 7(e) we decline to
* grant you any rights under trademark law for use of our trademarks.
*
* All the Product's GUI elements, including illustrations and icon sets, as
* well as technical writing content are licensed under the terms of the
* Creative Commons Attribution-ShareAlike 4.0 International. See the License
* terms at http://creativecommons.org/licenses/by-sa/4.0/legalcode
*
*/
#include "StringExt.h"
#include "PDFDoc.h"
#include "Decrypt.h"
#include "GlobalParams.h"
#include "SecurityHandler.h"
namespace PdfReader
{
//-------------------------------------------------------------------------------------------------------------------------------
// SecurityHandler
//-------------------------------------------------------------------------------------------------------------------------------
SecurityHandler *SecurityHandler::Make(PDFDoc *pDocument, Object *pEncryptDict)
{
SecurityHandler *pSecurityHandler = NULL;
Object oFilter;
pEncryptDict->DictLookup("Filter", &oFilter);
if (oFilter.IsName("Standard"))
{
pSecurityHandler = new StandardSecurityHandler(pDocument, pEncryptDict);
}
else if (oFilter.IsName())
{
// TO DO: Error "Couldn't find the security handler"
pSecurityHandler = NULL;
}
else
{
// TO DO: Error "Missing or invalid 'Filter' entry in encryption dictionary"
pSecurityHandler = NULL;
}
oFilter.Free();
return pSecurityHandler;
}
SecurityHandler::SecurityHandler(PDFDoc *pDocument)
{
m_pDocument = pDocument;
}
SecurityHandler::~SecurityHandler()
{
}
bool SecurityHandler::CheckEncryption(const std::wstring &ownerPassword, const std::wstring &userPassword)
{
return Authorize(ownerPassword, userPassword);
}
//-------------------------------------------------------------------------------------------------------------------------------
// StandardSecurityHandler
//-------------------------------------------------------------------------------------------------------------------------------
StandardSecurityHandler::StandardSecurityHandler(PDFDoc *pDocument, Object *pEncryptDict) :
SecurityHandler(pDocument), m_seOwnerEncryptionKey(NULL), m_seUserEncryptionKey(NULL), m_sePermsValue(NULL),
m_seFileID(NULL), m_seOwnerKey(NULL), m_seUserKey(NULL)
{
m_bValid = false;
Object oVersion, oRevision, oLength, oOwnerKey, oUserKey, oPermission, oPermsValue, oOwnerEncryptionKey, oUserEncryptionKey;
pEncryptDict->DictLookup("V", &oVersion);
pEncryptDict->DictLookup("R", &oRevision);
pEncryptDict->DictLookup("Length", &oLength);
pEncryptDict->DictLookup("O", &oOwnerKey);
pEncryptDict->DictLookup("U", &oUserKey);
pEncryptDict->DictLookup("P", &oPermission);
Object oFileID;
m_pDocument->GetXRef()->GetTrailerDict()->DictLookup("ID", &oFileID);
if (oVersion.IsInt() && oRevision.IsInt() && oOwnerKey.IsString() &&
oUserKey.IsString() && oPermission.IsInt())
{
m_nEncryptVersion = oVersion.GetInt();
m_nEncryptRevision = oRevision.GetInt();
m_eCryptType = cryptRC4;
// В случае Revision = 2, ключ должен быть 40-бит - некоторые PDF-генераторы неправильно пишут значение Length
if (m_nEncryptRevision == 2 || !oLength.IsInt())
{
m_nFileKeyLength = 5; // 5 байт = 40-бит
}
else
{
m_nFileKeyLength = oLength.GetInt() / 8;
}
m_bEncryptMetadata = true;
Object oCryptFilters, oStreamFilter, oStringFilter;
pEncryptDict->DictLookup("CF", &oCryptFilters);
pEncryptDict->DictLookup("StmF", &oStreamFilter);
pEncryptDict->DictLookup("StrF", &oStringFilter);
if (oCryptFilters.IsDict() && oStreamFilter.IsName() && oStringFilter.IsName() && !strcmp(oStreamFilter.GetName(), oStringFilter.GetName()))
{
Object oCryptCurFilter;
if (oCryptFilters.DictLookup(oStreamFilter.GetName(), &oCryptCurFilter)->IsDict())
{
Object oCFM;
oCryptCurFilter.DictLookup("CFM", &oCFM);
if (oCFM.IsName("V2"))
{
m_eCryptType = cryptRC4;
}
else if (oCFM.IsName("AESV2"))
{
m_eCryptType = cryptAES128;
}
else if (oCFM.IsName("AESV3"))
{
m_eCryptType = cryptAES256;
}
oCFM.Free();
}
oCryptCurFilter.Free();
Object oCFLength;
if (oCryptCurFilter.DictLookup("Length", &oCFLength)->IsInt())
{
// Согласно спецификации, должно быть oCFLength / 8
m_nFileKeyLength = oCFLength.GetInt();
}
oCFLength.Free();
}
oStringFilter.Free();
oStreamFilter.Free();
oCryptFilters.Free();
Object oEncryptMetadata;
if (pEncryptDict->DictLookup("EncryptMetadata", &oEncryptMetadata)->IsBool())
{
m_bEncryptMetadata = oEncryptMetadata.GetBool();
}
oEncryptMetadata.Free();
m_nPermissionFlags = oPermission.GetInt();
m_seOwnerKey = oOwnerKey.GetString()->Copy();
m_seUserKey = oUserKey.GetString()->Copy();
if (pEncryptDict->DictLookup("OE", &oOwnerEncryptionKey))
{
if (oOwnerEncryptionKey.IsString())
{
m_seOwnerEncryptionKey = oOwnerEncryptionKey.GetString()->Copy();
}
}
if (pEncryptDict->DictLookup("UE", &oUserEncryptionKey))
{
if (oUserEncryptionKey.IsString())
{
m_seUserEncryptionKey = oUserEncryptionKey.GetString()->Copy();
}
}
if (pEncryptDict->DictLookup("Perms", &oPermsValue))
{
if (oPermsValue.IsString())
{
m_sePermsValue = oPermsValue.GetString()->Copy();
}
}
if (oFileID.IsArray())
{
Object oFileIDString;
if (oFileID.ArrayGet(0, &oFileIDString)->IsString())
{
m_seFileID = oFileIDString.GetString()->Copy();
}
else
{
m_seFileID = new StringExt();
}
oFileIDString.Free();
}
else
{
m_seFileID = new StringExt();
}
m_bValid = true;
}
else
{
}
oFileID.Free();
oPermission.Free();
oUserKey.Free();
oOwnerKey.Free();
oLength.Free();
oRevision.Free();
oVersion.Free();
}
StandardSecurityHandler::~StandardSecurityHandler()
{
if (m_seFileID)
{
delete m_seFileID;
}
if (m_seOwnerKey)
{
delete m_seOwnerKey;
}
if (m_seUserKey)
{
delete m_seUserKey;
}
if (m_seOwnerEncryptionKey)
{
delete m_seOwnerEncryptionKey;
}
if (m_seUserEncryptionKey)
{
delete m_seUserEncryptionKey;
}
if (m_sePermsValue)
{
delete m_sePermsValue;
}
}
bool StandardSecurityHandler::Authorize(const std::wstring &ownerPassword, const std::wstring &userPassword)
{
if (!m_bValid)
{
return false;
}
if (!Decrypt::MakeFileKey(this, ownerPassword, userPassword))
{
return false;
}
return true;
}
}