mirror of https://github.com/JakubMelka/PDF4QT.git
2316 lines
80 KiB
C++
2316 lines
80 KiB
C++
// Copyright (C) 2019-2022 Jakub Melka
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//
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// This file is part of PDF4QT.
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//
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// PDF4QT is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// with the written consent of the copyright owner, any later version.
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//
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// PDF4QT is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with PDF4QT. If not, see <https://www.gnu.org/licenses/>.
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#include "pdfsecurityhandler.h"
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#include "pdfexception.h"
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#include "pdfencoding.h"
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#include "pdfvisitor.h"
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#include "pdfutils.h"
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#include "pdfdocumentbuilder.h"
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#include "pdfdbgheap.h"
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#include "pdfcertificatemanager.h"
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#include <QRandomGenerator>
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#include <openssl/rc4.h>
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#include <openssl/md5.h>
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#include <openssl/aes.h>
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#include <openssl/sha.h>
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#include <openssl/pkcs7.h>
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#include <openssl/pkcs12.h>
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#include <openssl/evp.h>
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#include <array>
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namespace pdf
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{
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template<typename T>
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using openssl_ptr = std::unique_ptr<T, void(*)(T*)>;
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// Padding password
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static constexpr std::array<uint8_t, 32> PDFPasswordPadding = {
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0x28, 0xBF, 0x4E, 0x5E, 0x4E, 0x75, 0x8A, 0x41,
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0x64, 0x00, 0x4E, 0x56, 0xFF, 0xFA, 0x01, 0x08,
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0x2E, 0x2E, 0x00, 0xB6, 0xD0, 0x68, 0x3E, 0x80,
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0x2F, 0x0C, 0xA9, 0xFE, 0x64, 0x53, 0x69, 0x7A
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};
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class PDFDecryptOrEncryptObjectVisitor : public PDFAbstractVisitor
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{
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public:
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enum class Mode
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{
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Decrypt,
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Encrypt
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};
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explicit PDFDecryptOrEncryptObjectVisitor(const PDFSecurityHandler* securityHandler, PDFObjectReference reference, Mode mode) :
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m_securityHandler(securityHandler),
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m_reference(reference),
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m_mode(mode)
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{
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m_objectStack.reserve(32);
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}
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virtual void visitNull() override;
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virtual void visitBool(bool value) override;
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virtual void visitInt(PDFInteger value) override;
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virtual void visitReal(PDFReal value) override;
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virtual void visitString(PDFStringRef string) override;
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virtual void visitName(PDFStringRef name) override;
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virtual void visitArray(const PDFArray* array) override;
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virtual void visitDictionary(const PDFDictionary* dictionary) override;
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virtual void visitStream(const PDFStream* stream) override;
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virtual void visitReference(const PDFObjectReference reference) override;
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PDFObject getProcessedObject();
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private:
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const PDFSecurityHandler* m_securityHandler = nullptr;
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std::vector<PDFObject> m_objectStack;
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PDFObjectReference m_reference;
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Mode m_mode = Mode::Decrypt;
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};
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void PDFDecryptOrEncryptObjectVisitor::visitNull()
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{
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m_objectStack.push_back(PDFObject::createNull());
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}
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void PDFDecryptOrEncryptObjectVisitor::visitBool(bool value)
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{
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m_objectStack.push_back(PDFObject::createBool(value));
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}
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void PDFDecryptOrEncryptObjectVisitor::visitInt(PDFInteger value)
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{
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m_objectStack.push_back(PDFObject::createInteger(value));
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}
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void PDFDecryptOrEncryptObjectVisitor::visitReal(PDFReal value)
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{
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m_objectStack.push_back(PDFObject::createReal(value));
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}
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void PDFDecryptOrEncryptObjectVisitor::visitString(PDFStringRef string)
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{
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switch (m_mode)
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{
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case pdf::PDFDecryptOrEncryptObjectVisitor::Mode::Decrypt:
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m_objectStack.push_back(PDFObject::createString(m_securityHandler->decrypt(string.getString(), m_reference, PDFSecurityHandler::EncryptionScope::String)));
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break;
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case pdf::PDFDecryptOrEncryptObjectVisitor::Mode::Encrypt:
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m_objectStack.push_back(PDFObject::createString(m_securityHandler->encrypt(string.getString(), m_reference, PDFSecurityHandler::EncryptionScope::String)));
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break;
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default:
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Q_ASSERT(false);
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break;
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}
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}
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void PDFDecryptOrEncryptObjectVisitor::visitName(PDFStringRef name)
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{
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m_objectStack.push_back(PDFObject::createName(name));
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}
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void PDFDecryptOrEncryptObjectVisitor::visitArray(const PDFArray* array)
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{
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acceptArray(array);
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// We have all objects on the stack
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Q_ASSERT(array->getCount() <= m_objectStack.size());
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auto it = std::next(m_objectStack.cbegin(), m_objectStack.size() - array->getCount());
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std::vector<PDFObject> objects(it, m_objectStack.cend());
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PDFObject object = PDFObject::createArray(std::make_shared<PDFArray>(qMove(objects)));
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m_objectStack.erase(it, m_objectStack.cend());
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m_objectStack.push_back(object);
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}
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void PDFDecryptOrEncryptObjectVisitor::visitDictionary(const PDFDictionary* dictionary)
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{
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Q_ASSERT(dictionary);
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// We must check, if it is or isn't a signature dictionary. If it is,
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// then don't decrypt/encrypt the Content value. We also don't check, if signature
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// isn't indirectly referenced by reference. Hope it isn't...
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const PDFObject& typeObject = dictionary->get("Type");
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bool isSignatureObject = (typeObject.isName() && typeObject.getString() == "Sig");
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std::vector<PDFDictionary::DictionaryEntry> entries;
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entries.reserve(dictionary->getCount());
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for (size_t i = 0, count = dictionary->getCount(); i < count; ++i)
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{
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if (isSignatureObject && dictionary->getKey(i) == "Contents")
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{
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entries.emplace_back(dictionary->getKey(i), dictionary->getValue(i));
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}
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else
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{
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dictionary->getValue(i).accept(this);
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entries.emplace_back(dictionary->getKey(i), m_objectStack.back());
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m_objectStack.pop_back();
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}
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}
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m_objectStack.push_back(PDFObject::createDictionary(std::make_shared<PDFDictionary>(qMove(entries))));
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}
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void PDFDecryptOrEncryptObjectVisitor::visitStream(const PDFStream* stream)
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{
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// Don't decrypt/encrypt, if it is a Metadata stream and Metadata encryption is turned off
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const PDFDictionary* dictionary = stream->getDictionary();
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const PDFObject& typeObject = dictionary->get("Type");
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bool isMetadata = (typeObject.isName() && typeObject.getString() == "Metadata");
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if (isMetadata && !m_securityHandler->isMetadataEncrypted())
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{
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m_objectStack.push_back(PDFObject::createStream(std::make_shared<PDFStream>(PDFDictionary(*dictionary), QByteArray(*stream->getContent()))));
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return;
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}
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// Decrypt/encrypt the dictionary
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visitDictionary(dictionary);
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PDFObject dictionaryObject = m_objectStack.back();
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m_objectStack.pop_back();
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// We must also handle situation, that stream has specified Crypt filter.
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// In this case, we must delegate decryption/encryption to the stream filters.
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PDFDictionary processedDictionary(*dictionaryObject.getDictionary());
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QByteArray processedData;
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if (!processedDictionary.hasKey("Crypt"))
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{
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// Is it an embedded file?
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const PDFObject& object = processedDictionary.get("Type");
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const bool isEmbeddedFile = object.isName() && object.getString() == "EmbeddedFile";
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const PDFSecurityHandler::EncryptionScope scope = !isEmbeddedFile ? PDFSecurityHandler::EncryptionScope::Stream : PDFSecurityHandler::EncryptionScope::EmbeddedFile;
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switch (m_mode)
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{
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case pdf::PDFDecryptOrEncryptObjectVisitor::Mode::Decrypt:
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processedData = m_securityHandler->decrypt(*stream->getContent(), m_reference, scope);
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break;
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case pdf::PDFDecryptOrEncryptObjectVisitor::Mode::Encrypt:
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processedData = m_securityHandler->encrypt(*stream->getContent(), m_reference, scope);
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break;
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default:
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Q_ASSERT(false);
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break;
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}
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processedDictionary.setEntry(PDFInplaceOrMemoryString("Length"), PDFObject::createInteger(processedData.size()));
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}
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else
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{
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switch (m_mode)
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{
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case pdf::PDFDecryptOrEncryptObjectVisitor::Mode::Decrypt:
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{
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processedData = *stream->getContent();
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processedDictionary.setEntry(PDFInplaceOrMemoryString(PDFSecurityHandler::OBJECT_REFERENCE_DICTIONARY_NAME), PDFObject::createReference(m_reference));
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break;
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}
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case pdf::PDFDecryptOrEncryptObjectVisitor::Mode::Encrypt:
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{
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processedData = *stream->getContent();
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processedDictionary.removeEntry(PDFSecurityHandler::OBJECT_REFERENCE_DICTIONARY_NAME);
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break;
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}
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default:
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Q_ASSERT(false);
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break;
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}
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}
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m_objectStack.push_back(PDFObject::createStream(std::make_shared<PDFStream>(qMove(processedDictionary), qMove(processedData))));
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}
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void PDFDecryptOrEncryptObjectVisitor::visitReference(const PDFObjectReference reference)
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{
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m_objectStack.push_back(PDFObject::createReference(reference));
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}
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PDFObject PDFDecryptOrEncryptObjectVisitor::getProcessedObject()
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{
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Q_ASSERT(m_objectStack.size() == 1);
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return qMove(m_objectStack.back());
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}
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PDFObject PDFSecurityHandler::decryptObject(const PDFObject& object, PDFObjectReference reference) const
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{
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PDFDecryptOrEncryptObjectVisitor visitor(this, reference, PDFDecryptOrEncryptObjectVisitor::Mode::Decrypt);
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object.accept(&visitor);
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return visitor.getProcessedObject();
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}
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PDFObject PDFSecurityHandler::encryptObject(const PDFObject& object, PDFObjectReference reference) const
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{
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PDFDecryptOrEncryptObjectVisitor visitor(this, reference, PDFDecryptOrEncryptObjectVisitor::Mode::Encrypt);
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object.accept(&visitor);
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return visitor.getProcessedObject();
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}
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void PDFSecurityHandler::parseCryptFilters(const PDFDictionary* dictionary, PDFSecurityHandler& handler, int Length)
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{
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const PDFObject& cryptFilterObjects = dictionary->get("CF");
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if (cryptFilterObjects.isDictionary())
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{
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const PDFDictionary* cryptFilters = cryptFilterObjects.getDictionary();
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for (size_t i = 0, cryptFilterCount = cryptFilters->getCount(); i < cryptFilterCount; ++i)
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{
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handler.m_cryptFilters[cryptFilters->getKey(i).getString()] = parseCryptFilter(Length, cryptFilters->getValue(i));
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}
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}
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// Now, add standard filters
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auto resolveFilter = [&handler](const QByteArray& name)
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{
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auto it = handler.m_cryptFilters.find(name);
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if (it == handler.m_cryptFilters.cend())
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{
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throw PDFException(PDFTranslationContext::tr("Unknown crypt filter '%1'.").arg(QString::fromLatin1(name)));
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}
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return it->second;
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};
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handler.m_filterStreams = resolveFilter(parseName(dictionary, "StmF", false, IDENTITY_FILTER_NAME));
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handler.m_filterStrings = resolveFilter(parseName(dictionary, "StrF", false, IDENTITY_FILTER_NAME));
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if (dictionary->hasKey("EFF"))
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{
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handler.m_filterEmbeddedFiles = resolveFilter(parseName(dictionary, "EFF", true));
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}
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else
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{
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// According to the PDF specification, if 'EFF' entry is omitted, then filter
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// for streams is used.
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handler.m_filterEmbeddedFiles = handler.m_filterStreams;
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}
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}
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void PDFSecurityHandler::parseDataStandardSecurityHandler(const PDFDictionary* dictionary, const QByteArray& id, int Length, PDFStandardSecurityHandler& handler)
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{
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int R = parseInt(dictionary, "R", true);
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if (R < 2 || R > 6)
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{
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throw PDFException(PDFTranslationContext::tr("Revision %1 of standard security handler is not supported.").arg(R));
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}
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handler.m_R = R;
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handler.m_filterDefault.authEvent = AuthEvent::DocOpen;
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handler.m_filterDefault.keyLength = Length / 8;
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handler.m_filterDefault.type = (R > 4) ? CryptFilterType::AESV3 : CryptFilterType::V2;
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auto readByteArray = [dictionary](const char* key, int size)
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{
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QByteArray result;
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const PDFObject& object = dictionary->get(key);
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if (object.isString())
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{
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result = object.getString();
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if (result.size() != size)
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{
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throw PDFException(PDFTranslationContext::tr("Expected %1 characters long string in entry '%2'. Provided length is %3.").arg(size).arg(QString::fromLatin1(key)).arg(result.size()));
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}
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}
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else
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{
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throw PDFException(PDFTranslationContext::tr("Expected %1 characters long string in entry '%2'.").arg(size).arg(QString::fromLatin1(key)));
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}
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return result;
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};
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handler.m_O = readByteArray("O", (R != 6 && R != 5) ? 32 : 48);
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handler.m_U = readByteArray("U", (R != 6 && R != 5) ? 32 : 48);
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handler.m_permissions = static_cast<uint32_t>(static_cast<int>(parseInt(dictionary, "P", true)));
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if (R == 6 || R == 5)
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{
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handler.m_OE = readByteArray("OE", 32);
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handler.m_UE = readByteArray("UE", 32);
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handler.m_Perms = readByteArray("Perms", 16);
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}
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const PDFObject& encryptMetadataObject = dictionary->get("EncryptMetadata");
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if (encryptMetadataObject.isBool())
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{
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handler.m_encryptMetadata = encryptMetadataObject.getBool();
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}
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handler.m_ID = id;
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}
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PDFSecurityHandlerPointer PDFSecurityHandler::createSecurityHandler(const PDFObject& encryptionDictionaryObject, const QByteArray& id)
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{
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if (encryptionDictionaryObject.isNull())
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{
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return PDFSecurityHandlerPointer(new PDFNoneSecurityHandler());
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}
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if (!encryptionDictionaryObject.isDictionary())
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{
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throw PDFException(PDFTranslationContext::tr("Invalid encryption dictionary."));
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}
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const PDFDictionary* dictionary = encryptionDictionaryObject.getDictionary();
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PDFSecurityHandlerPointer handler = createSecurityHandlerInstance(dictionary);
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if (!handler)
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{
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throw PDFException(PDFTranslationContext::tr("Unknown security handler."));
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}
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const int V = parseInt(dictionary, "V", true);
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// Check V
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if (V < 1 || V > 5)
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{
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throw PDFException(PDFTranslationContext::tr("Unsupported version of document encryption (V = %1).").arg(V));
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}
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// Only valid for V == 2 or V == 3, otherwise we set file encryption key length manually
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int Length = 40;
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switch (V)
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{
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case 1:
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Length = 40;
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break;
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case 2:
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case 3:
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Length = parseInt(dictionary, "Length", false, 40);
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break;
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case 4:
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Length = 128;
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break;
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case 5:
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Length = 256;
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break;
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default:
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Q_ASSERT(false);
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break;
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}
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// Create security handler
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handler->m_V = V;
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handler->m_keyLength = Length;
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// Add "Identity" filter to the filters
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CryptFilter identityFilter;
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identityFilter.type = CryptFilterType::Identity;
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handler->m_cryptFilters[IDENTITY_FILTER_NAME] = identityFilter;
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if (V == 4 || V == 5)
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{
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parseCryptFilters(dictionary, *handler, Length);
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}
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switch (handler->getMode())
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{
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case EncryptionMode::Standard:
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{
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auto typedHandler = qSharedPointerDynamicCast<PDFStandardSecurityHandler>(handler);
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parseDataStandardSecurityHandler(dictionary, id, Length, *typedHandler);
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break;
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}
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case EncryptionMode::PublicKey:
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{
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auto typedHandler = qSharedPointerDynamicCast<PDFPublicKeySecurityHandler>(handler);
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typedHandler->m_filterDefault.recipients = parseRecipients(dictionary);
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if (typedHandler->m_filterDefault.recipients.isEmpty())
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{
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auto it = typedHandler->m_cryptFilters.find("DefaultCryptFilter");
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if (it != typedHandler->m_cryptFilters.end())
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{
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typedHandler->m_filterDefault = it->second;
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}
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}
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break;
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}
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case EncryptionMode::None:
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case EncryptionMode::Custom:
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Q_ASSERT(false);
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break;
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default:
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Q_ASSERT(false);
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}
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return handler;
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}
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void PDFSecurityHandler::fillEncryptionDictionary(PDFObjectFactory& factory) const
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{
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factory.beginDictionaryItem("V");
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factory << PDFInteger(m_V);
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factory.endDictionaryItem();
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factory.beginDictionaryItem("Length");
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factory << PDFInteger(m_keyLength);
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factory.endDictionaryItem();
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if (m_V == 4 || m_V == 5)
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{
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factory.beginDictionaryItem("CF");
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factory.beginDictionary();
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QByteArray stmfName = "Identity";
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QByteArray strfName = stmfName;
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QByteArray effName = stmfName;
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for (const auto& cryptFilter : m_cryptFilters)
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{
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factory.beginDictionaryItem(cryptFilter.first);
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factory.beginDictionary();
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factory.beginDictionaryItem("CFM");
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if (cryptFilter.second == m_filterStrings)
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{
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strfName = cryptFilter.first;
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}
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if (cryptFilter.second == m_filterStreams)
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{
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stmfName = cryptFilter.first;
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}
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if (cryptFilter.second == m_filterEmbeddedFiles)
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{
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effName = cryptFilter.first;
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}
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switch (cryptFilter.second.type)
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{
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case CryptFilterType::None:
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// The application shall decrypt the data using the security handler
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factory << WrapName("None");
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break;
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case CryptFilterType::V2:
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// Use file encryption key for RC4 algorithm
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factory << WrapName("V2");
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|
break;
|
|
|
|
case CryptFilterType::AESV2:
|
|
// Use file encryption key for AES algorithm
|
|
factory << WrapName("AESV2");
|
|
break;
|
|
|
|
case CryptFilterType::AESV3:
|
|
// Use file encryption key for AES 256 bit algorithm
|
|
factory << WrapName("AESV3");
|
|
break;
|
|
|
|
case CryptFilterType::Identity:
|
|
// Don't decrypt anything, use identity function
|
|
factory << WrapName("Identity");
|
|
break;
|
|
|
|
default:
|
|
Q_ASSERT(false);
|
|
factory << WrapName("None");
|
|
break;
|
|
}
|
|
|
|
factory.endDictionaryItem();
|
|
|
|
factory.beginDictionaryItem("AuthEvent");
|
|
|
|
switch (cryptFilter.second.authEvent)
|
|
{
|
|
case AuthEvent::DocOpen:
|
|
factory << WrapName("DocOpen");
|
|
break;
|
|
|
|
case AuthEvent::EFOpen:
|
|
factory << WrapName("EFOpen");
|
|
break;
|
|
|
|
default:
|
|
Q_ASSERT(false);
|
|
break;
|
|
}
|
|
|
|
factory.endDictionaryItem();
|
|
|
|
factory.beginDictionaryItem("Length");
|
|
factory << cryptFilter.second.keyLength;
|
|
factory.endDictionaryItem();
|
|
|
|
factory.endDictionary();
|
|
|
|
factory.endDictionaryItem();
|
|
}
|
|
|
|
factory.endDictionary();
|
|
|
|
factory.endDictionaryItem();
|
|
|
|
// Store StmF, StrF, EFF
|
|
factory.beginDictionaryItem("StmF");
|
|
factory << WrapName(stmfName);
|
|
factory.endDictionaryItem();
|
|
|
|
factory.beginDictionaryItem("StrF");
|
|
factory << WrapName(strfName);
|
|
factory.endDictionaryItem();
|
|
|
|
factory.beginDictionaryItem("EFF");
|
|
factory << WrapName(effName);
|
|
factory.endDictionaryItem();
|
|
}
|
|
}
|
|
|
|
QByteArray PDFSecurityHandler::parseName(const PDFDictionary* dictionary, const char* key, bool required, const char* defaultValue)
|
|
{
|
|
const PDFObject& nameObject = dictionary->get(key);
|
|
|
|
if (nameObject.isNull())
|
|
{
|
|
return defaultValue ? QByteArray(defaultValue) : QByteArray();
|
|
}
|
|
|
|
if (!nameObject.isName())
|
|
{
|
|
if (required)
|
|
{
|
|
throw PDFException(PDFTranslationContext::tr("Invalid value for entry '%1' in encryption dictionary. Name expected.").arg(QString::fromLatin1(key)));
|
|
}
|
|
|
|
return defaultValue ? QByteArray(defaultValue) : QByteArray();
|
|
}
|
|
|
|
return nameObject.getString();
|
|
}
|
|
|
|
PDFInteger PDFSecurityHandler::parseInt(const PDFDictionary* dictionary, const char* key, bool required, PDFInteger defaultValue)
|
|
{
|
|
const PDFObject& intObject = dictionary->get(key);
|
|
if (!intObject.isInt())
|
|
{
|
|
if (required)
|
|
{
|
|
throw PDFException(PDFTranslationContext::tr("Invalid value for entry '%1' in encryption dictionary. Integer expected.").arg(QString::fromLatin1(key)));
|
|
}
|
|
|
|
return defaultValue;
|
|
}
|
|
|
|
return intObject.getInteger();
|
|
}
|
|
|
|
CryptFilter PDFSecurityHandler::parseCryptFilter(PDFInteger length, const PDFObject& object)
|
|
{
|
|
if (!object.isDictionary())
|
|
{
|
|
throw PDFException(PDFTranslationContext::tr("Crypt filter is not a dictionary!"));
|
|
}
|
|
const PDFDictionary* cryptFilterDictionary = object.getDictionary();
|
|
|
|
CryptFilter filter;
|
|
|
|
QByteArray CFMName = parseName(cryptFilterDictionary, "CFM", false, "None");
|
|
if (CFMName == "None")
|
|
{
|
|
filter.type = CryptFilterType::None;
|
|
}
|
|
else if (CFMName == "V2")
|
|
{
|
|
filter.type = CryptFilterType::V2;
|
|
}
|
|
else if (CFMName == "AESV2")
|
|
{
|
|
filter.type = CryptFilterType::AESV2;
|
|
}
|
|
else if (CFMName == "AESV3")
|
|
{
|
|
filter.type = CryptFilterType::AESV3;
|
|
}
|
|
else
|
|
{
|
|
throw PDFException(PDFTranslationContext::tr("Unsupported encryption algorithm '%1'.").arg(QString::fromLatin1(CFMName)));
|
|
}
|
|
|
|
QByteArray authEventName = parseName(cryptFilterDictionary, "AuthEvent", false, "DocOpen");
|
|
if (authEventName == "DocOpen")
|
|
{
|
|
filter.authEvent = AuthEvent::DocOpen;
|
|
}
|
|
else if (authEventName == "EFOpen")
|
|
{
|
|
filter.authEvent = AuthEvent::EFOpen;
|
|
}
|
|
else
|
|
{
|
|
throw PDFException(PDFTranslationContext::tr("Unsupported authorization event '%1'.").arg(QString::fromLatin1(authEventName)));
|
|
}
|
|
|
|
filter.keyLength = parseInt(cryptFilterDictionary, "Length", false, length / 8);
|
|
|
|
// Recipients
|
|
filter.recipients = parseRecipients(cryptFilterDictionary);
|
|
|
|
return filter;
|
|
}
|
|
|
|
PDFSecurityHandlerPointer PDFSecurityHandler::createSecurityHandlerInstance(const PDFDictionary* dictionary)
|
|
{
|
|
QByteArray filterName = parseName(dictionary, "Filter", true);
|
|
|
|
if (filterName == "Standard")
|
|
{
|
|
return PDFSecurityHandlerPointer(new PDFStandardSecurityHandler());
|
|
}
|
|
|
|
if (filterName == "Entrust.PPKEF" || filterName == "Adobe.PPKLite" || filterName == "Adobe.PubSec")
|
|
{
|
|
QByteArray subFilter = parseName(dictionary, "SubFilter", true);
|
|
if (subFilter == "adbe.pkcs7.s3" || subFilter == "adbe.pkcs7.s4" || subFilter == "adbe.pkcs7.s5")
|
|
{
|
|
return PDFSecurityHandlerPointer(new PDFPublicKeySecurityHandler());
|
|
}
|
|
}
|
|
|
|
return PDFSecurityHandlerPointer();
|
|
}
|
|
|
|
QByteArrayList PDFSecurityHandler::parseRecipients(const PDFDictionary* dictionary)
|
|
{
|
|
QByteArrayList result;
|
|
|
|
const PDFObject& recipients = dictionary->get("Recipients");
|
|
if (recipients.isArray())
|
|
{
|
|
for (const PDFObject& object : *recipients.getArray())
|
|
{
|
|
if (object.isString())
|
|
{
|
|
result << object.getString();
|
|
}
|
|
}
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
std::vector<uint8_t> PDFStandardOrPublicSecurityHandler::createV2_ObjectEncryptionKey(PDFObjectReference reference, CryptFilter filter) const
|
|
{
|
|
std::vector<uint8_t> inputKeyData = convertByteArrayToVector(m_authorizationData.fileEncryptionKey);
|
|
uint32_t objectNumber = qToLittleEndian(static_cast<uint32_t>(reference.objectNumber));
|
|
uint32_t generation = qToLittleEndian(static_cast<uint32_t>(reference.generation));
|
|
inputKeyData.insert(inputKeyData.cend(), { uint8_t(objectNumber & 0xFF), uint8_t((objectNumber >> 8) & 0xFF), uint8_t((objectNumber >> 16) & 0xFF), uint8_t(generation & 0xFF), uint8_t((generation >> 8) & 0xFF) });
|
|
std::vector<uint8_t> objectEncryptionKey(MD5_DIGEST_LENGTH, uint8_t(0));
|
|
MD5(inputKeyData.data(), inputKeyData.size(), objectEncryptionKey.data());
|
|
|
|
// Use up to (n + 5) bytes, maximally 16, from the digest as object encryption key
|
|
size_t objectEncryptionKeySize = qMin(filter.keyLength + 5, MD5_DIGEST_LENGTH);
|
|
objectEncryptionKey.resize(objectEncryptionKeySize);
|
|
|
|
return objectEncryptionKey;
|
|
}
|
|
|
|
std::vector<uint8_t> PDFStandardOrPublicSecurityHandler::createAESV2_ObjectEncryptionKey(PDFObjectReference reference) const
|
|
{
|
|
std::vector<uint8_t> inputKeyData = convertByteArrayToVector(m_authorizationData.fileEncryptionKey);
|
|
uint32_t objectNumber = qToLittleEndian(static_cast<uint32_t>(reference.objectNumber));
|
|
uint32_t generation = qToLittleEndian(static_cast<uint32_t>(reference.generation));
|
|
inputKeyData.insert(inputKeyData.cend(), { uint8_t(objectNumber & 0xFF), uint8_t((objectNumber >> 8) & 0xFF), uint8_t((objectNumber >> 16) & 0xFF), uint8_t(generation & 0xFF), uint8_t((generation >> 8) & 0xFF), 0x73, 0x41, 0x6C, 0x54 });
|
|
std::vector<uint8_t> objectEncryptionKey(MD5_DIGEST_LENGTH, uint8_t(0));
|
|
MD5(inputKeyData.data(), inputKeyData.size(), objectEncryptionKey.data());
|
|
|
|
return objectEncryptionKey;
|
|
}
|
|
|
|
QByteArray PDFStandardOrPublicSecurityHandler::decryptUsingFilter(const QByteArray& data, CryptFilter filter, PDFObjectReference reference) const
|
|
{
|
|
QByteArray decryptedData;
|
|
|
|
Q_ASSERT(m_authorizationData.isAuthorized());
|
|
|
|
struct AES_data
|
|
{
|
|
QByteArray initializationVector;
|
|
QByteArray paddedData;
|
|
};
|
|
|
|
auto prepareAES_data = [](const QByteArray& data)
|
|
{
|
|
AES_data result;
|
|
|
|
result.initializationVector = data.left(AES_BLOCK_SIZE);
|
|
|
|
// This is an error. But to handle it, we resize the vector
|
|
// with arbitrary data.
|
|
if (result.initializationVector.size() < AES_BLOCK_SIZE)
|
|
{
|
|
result.initializationVector.resize(AES_BLOCK_SIZE);
|
|
}
|
|
|
|
result.paddedData = data.mid(AES_BLOCK_SIZE);
|
|
|
|
// Remove errorneous data - we must have a data of multiple of AES_BLOCK_SIZE
|
|
const int remainder = result.paddedData.size() % AES_BLOCK_SIZE;
|
|
if (remainder != 0)
|
|
{
|
|
result.paddedData = result.paddedData.left(result.paddedData.size() - remainder);
|
|
}
|
|
|
|
return result;
|
|
};
|
|
|
|
auto removeAES_padding = [](const QByteArray& data)
|
|
{
|
|
if (data.isEmpty())
|
|
{
|
|
return data;
|
|
}
|
|
|
|
// If padding doesnt fit from 1 to AES_BLOCK_SIZE, then it is
|
|
// an error, but just clamp the value.
|
|
const int padding = data.back();
|
|
const int clampedPadding = qBound(1, padding, AES_BLOCK_SIZE);
|
|
|
|
return data.left(data.size() - clampedPadding);
|
|
};
|
|
|
|
switch (filter.type)
|
|
{
|
|
case CryptFilterType::None: // The application shall decrypt the data using the security handler
|
|
{
|
|
// This shouldn't occur, because in case the used filter has None value, then default filter
|
|
// is used and default filter can't have this value.
|
|
Q_ASSERT(false);
|
|
break;
|
|
}
|
|
|
|
case CryptFilterType::V2: // Use file encryption key for RC4 algorithm
|
|
{
|
|
std::vector<uint8_t> objectEncryptionKey = createV2_ObjectEncryptionKey(reference, filter);
|
|
decryptedData.resize(data.size());
|
|
|
|
RC4_KEY key = { };
|
|
RC4_set_key(&key, static_cast<int>(objectEncryptionKey.size()), objectEncryptionKey.data());
|
|
RC4(&key, data.size(), convertByteArrayToUcharPtr(data), convertByteArrayToUcharPtr(decryptedData));
|
|
|
|
break;
|
|
}
|
|
|
|
case CryptFilterType::AESV2: // Use file encryption key for AES algorithm
|
|
{
|
|
std::vector<uint8_t> objectEncryptionKey = createAESV2_ObjectEncryptionKey(reference);
|
|
|
|
// For AES algorithm, always use 16 bytes key (128 bit encryption mode)
|
|
|
|
AES_KEY key = { };
|
|
AES_set_decrypt_key(objectEncryptionKey.data(), static_cast<int>(objectEncryptionKey.size()) * 8, &key);
|
|
|
|
AES_data aes_data = prepareAES_data(data);
|
|
if (!aes_data.paddedData.isEmpty())
|
|
{
|
|
decryptedData.resize(aes_data.paddedData.size());
|
|
AES_cbc_encrypt(convertByteArrayToUcharPtr(aes_data.paddedData), convertByteArrayToUcharPtr(decryptedData), aes_data.paddedData.length(), &key, convertByteArrayToUcharPtr(aes_data.initializationVector), AES_DECRYPT);
|
|
decryptedData = removeAES_padding(decryptedData);
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
case CryptFilterType::AESV3: // Use file encryption key for AES 256 bit algorithm
|
|
{
|
|
Q_ASSERT(m_authorizationData.fileEncryptionKey.size() == 32);
|
|
AES_KEY key = { };
|
|
AES_set_decrypt_key(convertByteArrayToUcharPtr(m_authorizationData.fileEncryptionKey), static_cast<int>(m_authorizationData.fileEncryptionKey.size()) * 8, &key);
|
|
|
|
AES_data aes_data = prepareAES_data(data);
|
|
if (!aes_data.paddedData.isEmpty())
|
|
{
|
|
decryptedData.resize(aes_data.paddedData.size());
|
|
AES_cbc_encrypt(convertByteArrayToUcharPtr(aes_data.paddedData), convertByteArrayToUcharPtr(decryptedData), aes_data.paddedData.length(), &key, convertByteArrayToUcharPtr(aes_data.initializationVector), AES_DECRYPT);
|
|
decryptedData = removeAES_padding(decryptedData);
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
case CryptFilterType::Identity: // Don't decrypt anything, use identity function
|
|
{
|
|
decryptedData = data;
|
|
break;
|
|
}
|
|
}
|
|
|
|
return decryptedData;
|
|
}
|
|
|
|
QByteArray PDFStandardOrPublicSecurityHandler::encryptUsingFilter(const QByteArray& data, CryptFilter filter, PDFObjectReference reference) const
|
|
{
|
|
QByteArray encryptedData;
|
|
|
|
Q_ASSERT(m_authorizationData.isAuthorized());
|
|
|
|
struct AES_data
|
|
{
|
|
QByteArray initializationVector;
|
|
QByteArray paddedData;
|
|
};
|
|
|
|
auto prepareAES_data = [](const QByteArray& data)
|
|
{
|
|
AES_data result;
|
|
|
|
QRandomGenerator randomNumberGenerator = QRandomGenerator::securelySeeded();
|
|
|
|
result.initializationVector.resize(AES_BLOCK_SIZE);
|
|
for (int i = 0; i < AES_BLOCK_SIZE; ++i)
|
|
{
|
|
result.initializationVector[i] = uint8_t(randomNumberGenerator.generate());
|
|
}
|
|
|
|
result.paddedData = data;
|
|
|
|
// Add padding remainder according to the specification
|
|
int size = data.size();
|
|
const int paddingRemainder = AES_BLOCK_SIZE - (size % AES_BLOCK_SIZE);
|
|
|
|
result.initializationVector.reserve(result.initializationVector.size() + paddingRemainder);
|
|
for (int i = 0; i < paddingRemainder; ++i)
|
|
{
|
|
result.paddedData.push_back(paddingRemainder);
|
|
}
|
|
|
|
return result;
|
|
};
|
|
|
|
switch (filter.type)
|
|
{
|
|
case CryptFilterType::None: // The application shall encrypt the data using the security handler
|
|
{
|
|
// This shouldn't occur, because in case the used filter has None value, then default filter
|
|
// is used and default filter can't have this value.
|
|
Q_ASSERT(false);
|
|
break;
|
|
}
|
|
|
|
case CryptFilterType::V2: // Use file encryption key for RC4 algorithm
|
|
{
|
|
// This algorithm is same as the encrypt algorithm, because RC4 cipher is symmetrical
|
|
std::vector<uint8_t> objectEncryptionKey = createV2_ObjectEncryptionKey(reference, filter);
|
|
encryptedData.resize(data.size());
|
|
|
|
RC4_KEY key = { };
|
|
RC4_set_key(&key, static_cast<int>(objectEncryptionKey.size()), objectEncryptionKey.data());
|
|
RC4(&key, data.size(), convertByteArrayToUcharPtr(data), convertByteArrayToUcharPtr(encryptedData));
|
|
|
|
break;
|
|
}
|
|
|
|
case CryptFilterType::AESV2: // Use file encryption key for AES algorithm
|
|
{
|
|
std::vector<uint8_t> objectEncryptionKey = createAESV2_ObjectEncryptionKey(reference);
|
|
|
|
// For AES algorithm, always use 16 bytes key (128 bit encryption mode)
|
|
|
|
AES_KEY key = { };
|
|
AES_set_encrypt_key(objectEncryptionKey.data(), static_cast<int>(objectEncryptionKey.size()) * 8, &key);
|
|
|
|
AES_data aes_data = prepareAES_data(data);
|
|
if (!aes_data.paddedData.isEmpty())
|
|
{
|
|
QByteArray initializationVectorCopy = aes_data.initializationVector;
|
|
encryptedData.resize(aes_data.paddedData.size());
|
|
AES_cbc_encrypt(convertByteArrayToUcharPtr(aes_data.paddedData), convertByteArrayToUcharPtr(encryptedData), aes_data.paddedData.length(), &key, convertByteArrayToUcharPtr(aes_data.initializationVector), AES_ENCRYPT);
|
|
encryptedData.prepend(initializationVectorCopy);
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
case CryptFilterType::AESV3: // Use file encryption key for AES 256 bit algorithm
|
|
{
|
|
Q_ASSERT(m_authorizationData.fileEncryptionKey.size() == 32);
|
|
AES_KEY key = { };
|
|
AES_set_encrypt_key(convertByteArrayToUcharPtr(m_authorizationData.fileEncryptionKey), static_cast<int>(m_authorizationData.fileEncryptionKey.size()) * 8, &key);
|
|
|
|
AES_data aes_data = prepareAES_data(data);
|
|
if (!aes_data.paddedData.isEmpty())
|
|
{
|
|
QByteArray initializationVectorCopy = aes_data.initializationVector;
|
|
encryptedData.resize(aes_data.paddedData.size());
|
|
AES_cbc_encrypt(convertByteArrayToUcharPtr(aes_data.paddedData), convertByteArrayToUcharPtr(encryptedData), aes_data.paddedData.length(), &key, convertByteArrayToUcharPtr(aes_data.initializationVector), AES_ENCRYPT);
|
|
encryptedData.prepend(initializationVectorCopy);
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
case CryptFilterType::Identity: // Don't decrypt anything, use identity function
|
|
{
|
|
encryptedData = data;
|
|
break;
|
|
}
|
|
}
|
|
|
|
return encryptedData;
|
|
}
|
|
|
|
QByteArray PDFStandardOrPublicSecurityHandler::decrypt(const QByteArray& data, PDFObjectReference reference, EncryptionScope encryptionScope) const
|
|
{
|
|
CryptFilter filter = getCryptFilter(encryptionScope);
|
|
return decryptUsingFilter(data, filter, reference);
|
|
}
|
|
|
|
QByteArray PDFStandardOrPublicSecurityHandler::decryptByFilter(const QByteArray& data, const QByteArray& filterName, PDFObjectReference reference) const
|
|
{
|
|
auto it = m_cryptFilters.find(filterName);
|
|
if (it == m_cryptFilters.cend())
|
|
{
|
|
throw PDFException(PDFTranslationContext::tr("Crypt filter '%1' not found.").arg(QString::fromLatin1(filterName)));
|
|
}
|
|
|
|
return decryptUsingFilter(data, it->second, reference);
|
|
}
|
|
|
|
CryptFilter PDFStandardOrPublicSecurityHandler::getCryptFilter(EncryptionScope encryptionScope) const
|
|
{
|
|
CryptFilter filter = m_filterDefault;
|
|
|
|
switch (encryptionScope)
|
|
{
|
|
case EncryptionScope::String:
|
|
{
|
|
if (m_filterStrings.type != CryptFilterType::None)
|
|
{
|
|
filter = m_filterStrings;
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
case EncryptionScope::Stream:
|
|
{
|
|
if (m_filterStreams.type != CryptFilterType::None)
|
|
{
|
|
filter = m_filterStreams;
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
case EncryptionScope::EmbeddedFile:
|
|
{
|
|
if (m_filterEmbeddedFiles.type != CryptFilterType::None)
|
|
{
|
|
filter = m_filterEmbeddedFiles;
|
|
}
|
|
|
|
break;
|
|
}
|
|
}
|
|
|
|
return filter;
|
|
}
|
|
|
|
QByteArray PDFStandardOrPublicSecurityHandler::encrypt(const QByteArray& data, PDFObjectReference reference, EncryptionScope encryptionScope) const
|
|
{
|
|
CryptFilter filter = getCryptFilter(encryptionScope);
|
|
return encryptUsingFilter(data, filter, reference);
|
|
}
|
|
|
|
QByteArray PDFStandardOrPublicSecurityHandler::encryptByFilter(const QByteArray& data, const QByteArray& filterName, PDFObjectReference reference) const
|
|
{
|
|
auto it = m_cryptFilters.find(filterName);
|
|
if (it == m_cryptFilters.cend())
|
|
{
|
|
throw PDFException(PDFTranslationContext::tr("Crypt filter '%1' not found.").arg(QString::fromLatin1(filterName)));
|
|
}
|
|
|
|
return encryptUsingFilter(data, it->second, reference);
|
|
}
|
|
|
|
bool PDFStandardOrPublicSecurityHandler::isUnicodeNonAsciiSpaceCharacter(ushort unicode)
|
|
{
|
|
switch (unicode)
|
|
{
|
|
case 0x00A0:
|
|
case 0x1680:
|
|
case 0x2000:
|
|
case 0x2001:
|
|
case 0x2002:
|
|
case 0x2003:
|
|
case 0x2004:
|
|
case 0x2005:
|
|
case 0x2006:
|
|
case 0x2007:
|
|
case 0x2008:
|
|
case 0x2009:
|
|
case 0x200A:
|
|
case 0x200B:
|
|
case 0x202F:
|
|
case 0x205F:
|
|
case 0x3000:
|
|
return true;
|
|
|
|
default:
|
|
return false;
|
|
}
|
|
}
|
|
|
|
bool PDFStandardOrPublicSecurityHandler::isUnicodeMappedToNothing(ushort unicode)
|
|
{
|
|
switch (unicode)
|
|
{
|
|
case 0x00AD:
|
|
case 0x034F:
|
|
case 0x1806:
|
|
case 0x180B:
|
|
case 0x180C:
|
|
case 0x180D:
|
|
case 0x200B:
|
|
case 0x200C:
|
|
case 0x200D:
|
|
return true;
|
|
|
|
default:
|
|
return false;
|
|
}
|
|
}
|
|
|
|
QByteArray PDFStandardOrPublicSecurityHandler::adjustPassword(const QString& password, int revision)
|
|
{
|
|
QByteArray result;
|
|
|
|
switch (revision)
|
|
{
|
|
case 2:
|
|
case 3:
|
|
case 4:
|
|
{
|
|
// According to the PDF specification, convert string to PDFDocEncoding encoding
|
|
result = PDFEncoding::convertToEncoding(password, PDFEncoding::Encoding::PDFDoc);
|
|
break;
|
|
}
|
|
|
|
case 5:
|
|
case 6:
|
|
{
|
|
// According to the PDF specification, use SASLprep profile for stringprep RFC 4013, please see these websites:
|
|
// - RFC 4013: https://tools.ietf.org/html/rfc4013 (SASLprep profile for stringprep algorithm)
|
|
// - RFC 3454: https://tools.ietf.org/html/rfc3454 (stringprep algorithm - preparation of internationalized strings)
|
|
//
|
|
// Note: we don't do checks according the RFC 4013, just use the mapping and normalize string in KC
|
|
|
|
QString preparedPassword;
|
|
preparedPassword.reserve(password.size());
|
|
|
|
// RFC 4013 Section 2.1, use mapping
|
|
|
|
for (const QChar character : password)
|
|
{
|
|
if (isUnicodeMappedToNothing(character.unicode()))
|
|
{
|
|
// Mapped to nothing
|
|
continue;
|
|
}
|
|
|
|
if (isUnicodeNonAsciiSpaceCharacter(character.unicode()))
|
|
{
|
|
// Map to space character
|
|
preparedPassword += QChar(QChar::Space);
|
|
}
|
|
else
|
|
{
|
|
preparedPassword += character;
|
|
}
|
|
}
|
|
|
|
// RFC 4013, Section 2.2, normalization to KC
|
|
preparedPassword = preparedPassword.normalized(QString::NormalizationForm_KC);
|
|
|
|
// We don't do other checks. We will transform password to the UTF-8 encoding
|
|
// and according the PDF specification, we take only first 127 characters.
|
|
result = preparedPassword.toUtf8().left(127);
|
|
}
|
|
|
|
default:
|
|
result = password.toLatin1();
|
|
break;
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
PDFSecurityHandler* PDFStandardSecurityHandler::clone() const
|
|
{
|
|
return new PDFStandardSecurityHandler(*this);
|
|
}
|
|
|
|
PDFSecurityHandler::AuthorizationResult PDFStandardSecurityHandler::authenticate(const std::function<QString(bool*)>& getPasswordCallback, bool authorizeOwnerOnly)
|
|
{
|
|
QByteArray password;
|
|
bool passwordObtained = true;
|
|
|
|
// Clear the authorization data
|
|
m_authorizationData = AuthorizationData();
|
|
|
|
while (passwordObtained)
|
|
{
|
|
switch (m_R)
|
|
{
|
|
case 2:
|
|
case 3:
|
|
case 4:
|
|
{
|
|
// Try to authorize by owner password
|
|
{
|
|
QByteArray userPassword = createUserPasswordFromOwnerPassword(password);
|
|
QByteArray fileEncryptionKey = createFileEncryptionKey(userPassword);
|
|
QByteArray U = createEntryValueU_r234(fileEncryptionKey);
|
|
|
|
if (U == m_U)
|
|
{
|
|
// We have authorized owner access
|
|
m_authorizationData.authorizationResult = AuthorizationResult::OwnerAuthorized;
|
|
m_authorizationData.fileEncryptionKey = fileEncryptionKey;
|
|
return AuthorizationResult::OwnerAuthorized;
|
|
}
|
|
}
|
|
|
|
// Try to authorize user password
|
|
if (!authorizeOwnerOnly)
|
|
{
|
|
QByteArray fileEncryptionKey = createFileEncryptionKey(password);
|
|
QByteArray U = createEntryValueU_r234(fileEncryptionKey);
|
|
|
|
if (U == m_U)
|
|
{
|
|
// We have authorized user access
|
|
m_authorizationData.authorizationResult = AuthorizationResult::UserAuthorized;
|
|
m_authorizationData.fileEncryptionKey = fileEncryptionKey;
|
|
return AuthorizationResult::UserAuthorized;
|
|
}
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
case 5:
|
|
case 6:
|
|
{
|
|
UserOwnerData_r6 userData = parseParts(m_U);
|
|
UserOwnerData_r6 ownerData = parseParts(m_O);
|
|
|
|
auto createHash_r5 = [](const QByteArray& inputData)
|
|
{
|
|
QByteArray result(SHA256_DIGEST_LENGTH, char(0));
|
|
SHA256(convertByteArrayToUcharPtr(inputData), inputData.size(), convertByteArrayToUcharPtr(result));
|
|
return result;
|
|
};
|
|
|
|
auto createHash_r56 = [this, &createHash_r5](const QByteArray& input, const QByteArray& inputPassword, bool useUserKey)
|
|
{
|
|
return (m_R == 5) ? createHash_r5(input) : createHash_r6(input, inputPassword, useUserKey);
|
|
};
|
|
|
|
// Try to authorize owner password
|
|
{
|
|
QByteArray inputData = password + ownerData.validationSalt + m_U;
|
|
QByteArray hash = createHash_r56(inputData, password, true);
|
|
|
|
if (hash == ownerData.hash)
|
|
{
|
|
// We have authorized owner access. Now we must calculate the owner encryption key
|
|
|
|
QByteArray fileEncryptionKeyInputData = password + ownerData.keySalt + m_U;
|
|
QByteArray fileEncryptionDecryptionKey = createHash_r56(fileEncryptionKeyInputData, password, true);
|
|
|
|
Q_ASSERT(fileEncryptionDecryptionKey.size() == 32);
|
|
AES_KEY key = { };
|
|
AES_set_decrypt_key(convertByteArrayToUcharPtr(fileEncryptionDecryptionKey), fileEncryptionDecryptionKey.size() * 8, &key);
|
|
unsigned char aesInitializationVector[AES_BLOCK_SIZE] = { };
|
|
m_authorizationData.fileEncryptionKey.resize(m_OE.size());
|
|
AES_cbc_encrypt(convertByteArrayToUcharPtr(m_OE), convertByteArrayToUcharPtr(m_authorizationData.fileEncryptionKey), m_OE.size(), &key, aesInitializationVector, AES_DECRYPT);
|
|
|
|
m_authorizationData.authorizationResult = AuthorizationResult::OwnerAuthorized;
|
|
}
|
|
}
|
|
|
|
// Try to authorize user password
|
|
if (!m_authorizationData.isAuthorized() && !authorizeOwnerOnly)
|
|
{
|
|
QByteArray inputData = password + userData.validationSalt;
|
|
QByteArray hash = createHash_r56(inputData, password, false);
|
|
|
|
if (hash == userData.hash)
|
|
{
|
|
QByteArray fileEncryptionKeyInputData = password + userData.keySalt;
|
|
QByteArray fileEncryptionDecryptionKey = createHash_r56(fileEncryptionKeyInputData, password, false);
|
|
|
|
Q_ASSERT(fileEncryptionDecryptionKey.size() == 32);
|
|
AES_KEY key = { };
|
|
AES_set_decrypt_key(convertByteArrayToUcharPtr(fileEncryptionDecryptionKey), fileEncryptionDecryptionKey.size() * 8, &key);
|
|
unsigned char aesInitializationVector[AES_BLOCK_SIZE] = { };
|
|
m_authorizationData.fileEncryptionKey.resize(m_UE.size());
|
|
AES_cbc_encrypt(convertByteArrayToUcharPtr(m_UE), convertByteArrayToUcharPtr(m_authorizationData.fileEncryptionKey), m_UE.size(), &key, aesInitializationVector, AES_DECRYPT);
|
|
|
|
// We have authorized user access
|
|
m_authorizationData.authorizationResult = AuthorizationResult::UserAuthorized;
|
|
}
|
|
}
|
|
|
|
// Stop, if we authorized the document usage
|
|
if (m_authorizationData.isAuthorized())
|
|
{
|
|
// According the PDF specification, we must also check, if flags are not manipulated.
|
|
Q_ASSERT(m_Perms.size() == AES_BLOCK_SIZE);
|
|
AES_KEY key = { };
|
|
AES_set_decrypt_key(convertByteArrayToUcharPtr(m_authorizationData.fileEncryptionKey), m_authorizationData.fileEncryptionKey.size() * 8, &key);
|
|
QByteArray decodedPerms(m_Perms.size(), char(0));
|
|
AES_ecb_encrypt(convertByteArrayToUcharPtr(m_Perms), convertByteArrayToUcharPtr(decodedPerms), &key, AES_DECRYPT);
|
|
|
|
// 1) Checks, if bytes 9, 10, 11 are 'a', 'd', 'b'
|
|
if (decodedPerms[9] != 'a' || decodedPerms[10] != 'd' || decodedPerms[11] != 'b')
|
|
{
|
|
throw PDFException(PDFTranslationContext::tr("Permissions entry in the Encryption dictionary is invalid."));
|
|
}
|
|
|
|
// 2) Verify, that bytes 0-3 are valid permissions entry
|
|
const uint32_t permissions = qFromLittleEndian(*reinterpret_cast<const uint32_t*>(decodedPerms.data()));
|
|
if (permissions != m_permissions)
|
|
{
|
|
throw PDFException(PDFTranslationContext::tr("Security permissions are manipulated. Can't open the document."));
|
|
}
|
|
|
|
// 3) Verify, that byte 8 is 'T' or 'F' and is equal to EncryptMetadata entry
|
|
if (decodedPerms[8] != 'T' && decodedPerms[8] != 'F')
|
|
{
|
|
throw PDFException(PDFTranslationContext::tr("Security permissions are manipulated. Can't open the document."));
|
|
}
|
|
if ((decodedPerms[8] == 'T') != m_encryptMetadata)
|
|
{
|
|
throw PDFException(PDFTranslationContext::tr("Security permissions are manipulated. Can't open the document."));
|
|
}
|
|
|
|
return m_authorizationData.authorizationResult;
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
default:
|
|
return AuthorizationResult::Failed;
|
|
}
|
|
|
|
password = adjustPassword(getPasswordCallback(&passwordObtained), m_R);
|
|
}
|
|
|
|
return AuthorizationResult::Cancelled;
|
|
}
|
|
|
|
PDFObject PDFStandardSecurityHandler::createEncryptionDictionaryObject() const
|
|
{
|
|
PDFObjectFactory factory;
|
|
|
|
factory.beginDictionary();
|
|
|
|
fillEncryptionDictionary(factory);
|
|
|
|
factory.beginDictionaryItem("Filter");
|
|
factory << WrapName("Standard");
|
|
factory.endDictionaryItem();
|
|
|
|
factory.beginDictionaryItem("R");
|
|
factory << PDFInteger(m_R);
|
|
factory.endDictionaryItem();
|
|
|
|
factory.beginDictionaryItem("O");
|
|
factory << WrapString(m_O);
|
|
factory.endDictionaryItem();
|
|
|
|
factory.beginDictionaryItem("U");
|
|
factory << WrapString(m_U);
|
|
factory.endDictionaryItem();
|
|
|
|
if (m_R == 6)
|
|
{
|
|
factory.beginDictionaryItem("OE");
|
|
factory << WrapString(m_OE);
|
|
factory.endDictionaryItem();
|
|
|
|
factory.beginDictionaryItem("UE");
|
|
factory << WrapString(m_UE);
|
|
factory.endDictionaryItem();
|
|
}
|
|
|
|
factory.beginDictionaryItem("P");
|
|
factory << PDFInteger(int32_t(m_permissions));
|
|
factory.endDictionaryItem();
|
|
|
|
if (m_R == 6)
|
|
{
|
|
factory.beginDictionaryItem("Perms");
|
|
factory << WrapString(m_Perms);
|
|
factory.endDictionaryItem();
|
|
}
|
|
|
|
if (m_V == 4 || m_V == 5)
|
|
{
|
|
factory.beginDictionaryItem("EncryptMetadata");
|
|
factory << m_encryptMetadata;
|
|
factory.endDictionaryItem();
|
|
}
|
|
|
|
factory.endDictionary();
|
|
|
|
return factory.takeObject();
|
|
}
|
|
|
|
QByteArray PDFStandardSecurityHandler::createFileEncryptionKey(const QByteArray& password) const
|
|
{
|
|
QByteArray result;
|
|
|
|
switch (m_R)
|
|
{
|
|
case 2:
|
|
case 3:
|
|
case 4:
|
|
{
|
|
std::array<uint8_t, 32> paddedPassword = createPaddedPassword32(password);
|
|
uint32_t transformedPermissions = qToLittleEndian(m_permissions);
|
|
|
|
MD5_CTX context = { };
|
|
MD5_Init(&context);
|
|
MD5_Update(&context, paddedPassword.data(), paddedPassword.size());
|
|
MD5_Update(&context, m_O.constData(), m_O.size());
|
|
MD5_Update(&context, &transformedPermissions, sizeof(transformedPermissions));
|
|
MD5_Update(&context, m_ID.constData(), m_ID.size());
|
|
|
|
if (!m_encryptMetadata)
|
|
{
|
|
constexpr uint32_t value = 0xFFFFFFFF;
|
|
MD5_Update(&context, &value, sizeof(value));
|
|
}
|
|
|
|
std::array<uint8_t, MD5_DIGEST_LENGTH> fileEncryptionKey = { };
|
|
MD5_Final(fileEncryptionKey.data(), &context);
|
|
|
|
const int keyByteLength = m_keyLength / 8;
|
|
if (keyByteLength > MD5_DIGEST_LENGTH)
|
|
{
|
|
throw PDFException(PDFTranslationContext::tr("Encryption key length (%1) exceeded maximal value of %2.").arg(keyByteLength).arg(MD5_DIGEST_LENGTH));
|
|
}
|
|
|
|
if (m_R >= 3)
|
|
{
|
|
for (int i = 0; i < 50; ++i)
|
|
{
|
|
|
|
MD5_Init(&context);
|
|
MD5_Update(&context, fileEncryptionKey.data(), keyByteLength);
|
|
MD5_Final(fileEncryptionKey.data(), &context);
|
|
}
|
|
}
|
|
|
|
result.resize(keyByteLength);
|
|
std::copy_n(fileEncryptionKey.cbegin(), keyByteLength, result.begin());
|
|
break;
|
|
}
|
|
|
|
case 5:
|
|
case 6:
|
|
{
|
|
// This function must not be called with revision 5/6
|
|
Q_ASSERT(false);
|
|
break;
|
|
}
|
|
|
|
default:
|
|
{
|
|
throw PDFException(PDFTranslationContext::tr("Revision %1 of standard security handler is not supported.").arg(m_R));
|
|
}
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
QByteArray PDFStandardSecurityHandler::createEntryValueU_r234(const QByteArray& fileEncryptionKey) const
|
|
{
|
|
QByteArray result;
|
|
|
|
switch (m_R)
|
|
{
|
|
case 2:
|
|
{
|
|
RC4_KEY key = { };
|
|
RC4_set_key(&key, fileEncryptionKey.size(), convertByteArrayToUcharPtr(fileEncryptionKey));
|
|
|
|
result.resize(static_cast<int>(PDFPasswordPadding.size()));
|
|
RC4(&key, PDFPasswordPadding.size(), PDFPasswordPadding.data(), convertByteArrayToUcharPtr(result));
|
|
break;
|
|
}
|
|
|
|
case 3:
|
|
case 4:
|
|
{
|
|
std::array<uint8_t, MD5_DIGEST_LENGTH> hash = { };
|
|
|
|
MD5_CTX context = { };
|
|
MD5_Init(&context);
|
|
MD5_Update(&context, PDFPasswordPadding.data(), PDFPasswordPadding.size());
|
|
MD5_Update(&context, m_ID.data(), m_ID.size());
|
|
MD5_Final(hash.data(), &context);
|
|
|
|
RC4_KEY key = { };
|
|
RC4_set_key(&key, fileEncryptionKey.size(), convertByteArrayToUcharPtr(fileEncryptionKey));
|
|
|
|
std::array<uint8_t, MD5_DIGEST_LENGTH> encryptedHash = { };
|
|
std::array<uint8_t, MD5_DIGEST_LENGTH> targetBuffer = { };
|
|
RC4(&key, hash.size(), hash.data(), encryptedHash.data());
|
|
|
|
QByteArray transformedKey = fileEncryptionKey;
|
|
for (int i = 1; i <= 19; ++i)
|
|
{
|
|
for (int j = 0, keySize = fileEncryptionKey.size(); j < keySize; ++j)
|
|
{
|
|
transformedKey[j] = static_cast<uint8_t>(fileEncryptionKey[j]) ^ static_cast<uint8_t>(i);
|
|
}
|
|
|
|
RC4_set_key(&key, transformedKey.size(), convertByteArrayToUcharPtr(transformedKey));
|
|
RC4(&key, encryptedHash.size(), encryptedHash.data(), targetBuffer.data());
|
|
encryptedHash = targetBuffer;
|
|
}
|
|
|
|
// We do a hack here. In the PDF's specification, it is written, that arbitrary 16 bytes
|
|
// are appended to the 16 bytes result. We use the last 16 bytes of the U entry, because we
|
|
// want to compare byte arrays entirely (otherwise we must compare only 16 bytes to authenticate
|
|
// user password).
|
|
result = m_U;
|
|
result.detach();
|
|
|
|
if (result.size() != 32)
|
|
{
|
|
// In case of error, we resize it to correct size. We can't assume, that m_U has correct length.
|
|
result.resize(32);
|
|
}
|
|
|
|
std::copy_n(encryptedHash.begin(), encryptedHash.size(), result.begin());
|
|
break;
|
|
}
|
|
|
|
default:
|
|
{
|
|
throw PDFException(PDFTranslationContext::tr("Revision %1 of standard security handler is not supported.").arg(m_R));
|
|
}
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
QByteArray PDFStandardSecurityHandler::createUserPasswordFromOwnerPassword(const QByteArray& password) const
|
|
{
|
|
QByteArray result;
|
|
|
|
std::array<uint8_t, 32> paddedPassword = createPaddedPassword32(password);
|
|
std::array<uint8_t, MD5_DIGEST_LENGTH> hash;
|
|
|
|
MD5_CTX context = { };
|
|
MD5_Init(&context);
|
|
MD5_Update(&context, paddedPassword.data(), paddedPassword.size());
|
|
MD5_Final(hash.data(), &context);
|
|
|
|
const int keyByteLength = m_keyLength / 8;
|
|
if (keyByteLength > MD5_DIGEST_LENGTH)
|
|
{
|
|
throw PDFException(PDFTranslationContext::tr("Encryption key length (%1) exceeded maximal value of %2.").arg(keyByteLength).arg(MD5_DIGEST_LENGTH));
|
|
}
|
|
|
|
if (m_R >= 3)
|
|
{
|
|
for (int i = 0; i < 50; ++i)
|
|
{
|
|
|
|
MD5_Init(&context);
|
|
MD5_Update(&context, hash.data(), keyByteLength);
|
|
MD5_Final(hash.data(), &context);
|
|
}
|
|
}
|
|
|
|
switch (m_R)
|
|
{
|
|
case 2:
|
|
{
|
|
RC4_KEY key = { };
|
|
RC4_set_key(&key, keyByteLength, hash.data());
|
|
result.resize(m_O.size());
|
|
RC4(&key, m_O.size(), convertByteArrayToUcharPtr(m_O), convertByteArrayToUcharPtr(result));
|
|
break;
|
|
}
|
|
|
|
case 3:
|
|
case 4:
|
|
{
|
|
QByteArray buffer = m_O;
|
|
QByteArray transformedKey;
|
|
transformedKey.resize(keyByteLength);
|
|
std::copy_n(hash.data(), keyByteLength, transformedKey.data());
|
|
|
|
for (int i = 19; i >= 0; --i)
|
|
{
|
|
for (int j = 0, keySize = transformedKey.size(); j < keySize; ++j)
|
|
{
|
|
transformedKey[j] = static_cast<uint8_t>(hash[j]) ^ static_cast<uint8_t>(i);
|
|
}
|
|
|
|
RC4_KEY key = { };
|
|
RC4_set_key(&key, transformedKey.size(), convertByteArrayToUcharPtr(transformedKey));
|
|
RC4(&key, buffer.size(), convertByteArrayToUcharPtr(buffer), convertByteArrayToUcharPtr(buffer));
|
|
}
|
|
|
|
result = buffer;
|
|
break;
|
|
}
|
|
|
|
default:
|
|
{
|
|
throw PDFException(PDFTranslationContext::tr("Revision %1 of standard security handler is not supported.").arg(m_R));
|
|
}
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
std::array<uint8_t, 32> PDFStandardSecurityHandler::createPaddedPassword32(const QByteArray& password) const
|
|
{
|
|
std::array<uint8_t, 32> result = { };
|
|
|
|
int copiedBytes = qMin<int>(static_cast<int>(result.size()), password.size());
|
|
auto it = result.begin();
|
|
|
|
for (int i = 0; i < copiedBytes; ++i)
|
|
{
|
|
*it++ = static_cast<uint8_t>(password[i]);
|
|
}
|
|
|
|
auto itPadding = PDFPasswordPadding.cbegin();
|
|
for (; it != result.cend();)
|
|
{
|
|
Q_ASSERT(itPadding != PDFPasswordPadding.cend());
|
|
*it++ = *itPadding++;
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
QByteArray PDFStandardSecurityHandler::createHash_r6(const QByteArray& input, const QByteArray& inputPassword, bool useUserKey) const
|
|
{
|
|
QByteArray result;
|
|
|
|
// First compute sha-256 digest of the input
|
|
std::array<uint8_t, SHA256_DIGEST_LENGTH> inputDigest = { };
|
|
SHA256(convertByteArrayToUcharPtr(input), input.size(), inputDigest.data());
|
|
std::vector<uint8_t> K(inputDigest.cbegin(), inputDigest.cend());
|
|
|
|
// Fill the user key, if we use it
|
|
std::vector<uint8_t> userKey;
|
|
if (useUserKey)
|
|
{
|
|
userKey.resize(m_U.size());
|
|
std::copy_n(m_U.constData(), m_U.size(), userKey.begin());
|
|
}
|
|
const size_t userKeySize = userKey.size();
|
|
|
|
// Fill the input password
|
|
std::vector<uint8_t> password(inputPassword.constData(), inputPassword.constData() + inputPassword.size());
|
|
const size_t passwordSize = password.size();
|
|
|
|
std::vector<uint8_t> K1;
|
|
std::vector<uint8_t> E;
|
|
|
|
int round = 0;
|
|
while (round < 64 || round < E.back() + 32)
|
|
{
|
|
const size_t blockCount = 64;
|
|
const size_t KSize = K.size();
|
|
const size_t sequenceSize = passwordSize + KSize + userKeySize;
|
|
const size_t totalSize = blockCount * sequenceSize;
|
|
|
|
// Resize the arrays
|
|
K1.resize(totalSize);
|
|
E.resize(totalSize);
|
|
|
|
// a) fill the input array K1 with data
|
|
auto it = K1.begin();
|
|
for (size_t i = 0; i < blockCount; ++i)
|
|
{
|
|
std::copy_n(password.cbegin(), passwordSize, it);
|
|
std::advance(it, passwordSize);
|
|
|
|
std::copy_n(K.cbegin(), KSize, it);
|
|
std::advance(it, KSize);
|
|
|
|
std::copy_n(userKey.cbegin(), userKeySize, it);
|
|
std::advance(it, userKeySize);
|
|
}
|
|
Q_ASSERT(it == K1.cend());
|
|
Q_ASSERT(K.size() >= 32);
|
|
|
|
// b) encrypt K1 with AES-128 in CBC mode, first 16 bytes of K is key,
|
|
// second 16 bytes in K is initialization vector for AES algorithm.
|
|
AES_KEY key = { };
|
|
AES_set_encrypt_key(K.data(), 128, &key);
|
|
AES_cbc_encrypt(K1.data(), E.data(), K1.size(), &key, K.data() + 16, AES_ENCRYPT);
|
|
|
|
// c) we take first 16 bytes from E as unsigned 128 bit big-endian integer and compute
|
|
// remainder modulo 3. Then we decide which SHA function we will use.
|
|
|
|
// We can't directly modulo 128 bit unsigned number, because we do not have 128 bit arithmetic (yet).
|
|
// We will use following trick from https://math.stackexchange.com/questions/2727954/bit-representation-and-divisibility-by-3
|
|
//
|
|
// 2^n mod 3 = 2 for n = 1, 3, 5, 7, 9, ...
|
|
// 2^n mod 3 = 1 for n = 0, 2, 4, 6, 8, ...
|
|
//
|
|
// Also, it doesn't matter the endianity of the numbers, becase for example, when we change endianity of 16 bit
|
|
// numbers, then bits 0-7 became 8-15, so even/odd bits become also even/odd.
|
|
|
|
int remainderAccumulator = 0;
|
|
for (size_t i = 0; i < 16; ++i)
|
|
{
|
|
uint8_t byte = E[i];
|
|
|
|
int currentRemainder = 1;
|
|
for (uint8_t i = 0; i < 8; ++i)
|
|
{
|
|
if ((byte >> i) & 1)
|
|
{
|
|
remainderAccumulator += currentRemainder;
|
|
}
|
|
|
|
// We alternate the remainder 1, 2, 1, 2, 1, 2, ...
|
|
currentRemainder = 3 - currentRemainder;
|
|
}
|
|
}
|
|
remainderAccumulator = remainderAccumulator % 3;
|
|
|
|
// d) according to the remainder, decide, which function we will use
|
|
switch (remainderAccumulator)
|
|
{
|
|
case 0:
|
|
{
|
|
K.resize(SHA256_DIGEST_LENGTH);
|
|
SHA256(E.data(), E.size(), K.data());
|
|
break;
|
|
}
|
|
|
|
case 1:
|
|
{
|
|
K.resize(SHA384_DIGEST_LENGTH);
|
|
SHA384(E.data(), E.size(), K.data());
|
|
break;
|
|
}
|
|
|
|
case 2:
|
|
{
|
|
K.resize(SHA512_DIGEST_LENGTH);
|
|
SHA512(E.data(), E.size(), K.data());
|
|
break;
|
|
}
|
|
|
|
default:
|
|
{
|
|
// Invalid value, can't occur
|
|
Q_ASSERT(false);
|
|
break;
|
|
}
|
|
}
|
|
|
|
++round;
|
|
}
|
|
|
|
Q_ASSERT(K.size() >= 32);
|
|
|
|
// Clamp result to 32 bytes
|
|
result.resize(32);
|
|
std::copy_n(K.data(), 32, result.data());
|
|
return result;
|
|
}
|
|
|
|
PDFStandardSecurityHandler::UserOwnerData_r6 PDFStandardSecurityHandler::parseParts(const QByteArray& data) const
|
|
{
|
|
UserOwnerData_r6 result;
|
|
Q_ASSERT(data.size() == 48);
|
|
|
|
result.hash = data.left(32);
|
|
result.validationSalt = data.mid(32, 8);
|
|
result.keySalt = data.mid(40, 8);
|
|
|
|
return result;
|
|
}
|
|
|
|
PDFSecurityHandlerPointer PDFSecurityHandlerFactory::createSecurityHandler(const SecuritySettings& settings)
|
|
{
|
|
if (settings.algorithm == Algorithm::None)
|
|
{
|
|
return PDFSecurityHandlerPointer(new PDFNoneSecurityHandler);
|
|
}
|
|
|
|
// Jakub Melka: create standard security handler, with given settings
|
|
PDFStandardSecurityHandler* handler = new PDFStandardSecurityHandler();
|
|
handler->m_ID = settings.id;
|
|
|
|
const bool isEncryptingEmbeddedFilesOnly = settings.encryptContents == EncryptContents::EmbeddedFiles;
|
|
|
|
switch (settings.algorithm)
|
|
{
|
|
case RC4:
|
|
{
|
|
handler->m_V = 4;
|
|
handler->m_keyLength = 128;
|
|
|
|
CryptFilter defaultFilter;
|
|
defaultFilter.type = CryptFilterType::V2;
|
|
defaultFilter.authEvent = !isEncryptingEmbeddedFilesOnly ? AuthEvent::DocOpen : AuthEvent::EFOpen;
|
|
defaultFilter.keyLength = handler->m_keyLength / 8;
|
|
handler->m_filterDefault = defaultFilter;
|
|
break;
|
|
}
|
|
|
|
case AES_128:
|
|
{
|
|
handler->m_V = 4;
|
|
handler->m_keyLength = 128;
|
|
|
|
CryptFilter defaultFilter;
|
|
defaultFilter.type = CryptFilterType::AESV2;
|
|
defaultFilter.authEvent = !isEncryptingEmbeddedFilesOnly ? AuthEvent::DocOpen : AuthEvent::EFOpen;
|
|
defaultFilter.keyLength = handler->m_keyLength / 8;
|
|
handler->m_filterDefault = defaultFilter;
|
|
break;
|
|
}
|
|
|
|
case AES_256:
|
|
{
|
|
handler->m_V = 5;
|
|
handler->m_keyLength = 256;
|
|
|
|
CryptFilter defaultFilter;
|
|
defaultFilter.type = CryptFilterType::AESV3;
|
|
defaultFilter.authEvent = !isEncryptingEmbeddedFilesOnly ? AuthEvent::DocOpen : AuthEvent::EFOpen;
|
|
defaultFilter.keyLength = handler->m_keyLength / 8;
|
|
handler->m_filterDefault = defaultFilter;
|
|
break;
|
|
}
|
|
|
|
default:
|
|
Q_ASSERT(false);
|
|
break;
|
|
}
|
|
|
|
CryptFilter identityFilter;
|
|
identityFilter.type = CryptFilterType::Identity;
|
|
|
|
switch (settings.encryptContents)
|
|
{
|
|
case All:
|
|
handler->m_filterStrings = handler->m_filterDefault;
|
|
handler->m_filterStreams = handler->m_filterDefault;
|
|
handler->m_filterEmbeddedFiles = handler->m_filterDefault;
|
|
handler->m_encryptMetadata = true;
|
|
break;
|
|
|
|
case AllExceptMetadata:
|
|
handler->m_filterStrings = handler->m_filterDefault;
|
|
handler->m_filterStreams = handler->m_filterDefault;
|
|
handler->m_filterEmbeddedFiles = handler->m_filterDefault;
|
|
handler->m_encryptMetadata = false;
|
|
break;
|
|
|
|
case EmbeddedFiles:
|
|
handler->m_filterStrings = identityFilter;
|
|
handler->m_filterStreams = identityFilter;
|
|
handler->m_filterEmbeddedFiles = handler->m_filterDefault;
|
|
handler->m_encryptMetadata = false;
|
|
break;
|
|
|
|
default:
|
|
Q_ASSERT(false);
|
|
break;
|
|
}
|
|
|
|
handler->m_cryptFilters["StdCF"] = handler->m_filterDefault;
|
|
handler->m_R = getRevisionFromAlgorithm(settings.algorithm);
|
|
handler->m_permissions = settings.permissions | 0xFFFFF000;
|
|
|
|
QByteArray adjustedOwnerPassword = handler->adjustPassword(settings.ownerPassword, handler->m_R);
|
|
QByteArray adjustedUserPassword = handler->adjustPassword(settings.userPassword, handler->m_R);
|
|
|
|
// Generate encryption entries
|
|
switch (handler->m_R)
|
|
{
|
|
case 2:
|
|
case 3:
|
|
case 4:
|
|
{
|
|
// Trick for computing "O" entry for revisions 2,3,4: in O entry, there is stored
|
|
// user password encrypted by owner password. Because RC4 cipher is symmetric, we
|
|
// can store user password in "O" entry and then use standard function to retrieve
|
|
// user password, which in fact will be encrypted user password.
|
|
|
|
std::array<uint8_t, 32> paddedUserPasswordArray = handler->createPaddedPassword32(adjustedUserPassword);
|
|
QByteArray paddedUserPassword;
|
|
paddedUserPassword.resize(int(paddedUserPasswordArray.size()));
|
|
std::copy(paddedUserPasswordArray.cbegin(), paddedUserPasswordArray.cend(), paddedUserPassword.data());
|
|
handler->m_O = paddedUserPassword;
|
|
QByteArray entryO = handler->createUserPasswordFromOwnerPassword(adjustedOwnerPassword);
|
|
handler->m_O = entryO;
|
|
Q_ASSERT(handler->createUserPasswordFromOwnerPassword(adjustedOwnerPassword) == paddedUserPassword);
|
|
|
|
handler->m_U.resize(32);
|
|
QRandomGenerator randomNumberGenerator = QRandomGenerator::securelySeeded();
|
|
for (int i = 0; i < handler->m_U.size(); ++i)
|
|
{
|
|
handler->m_U[i] = char(randomNumberGenerator.generate());
|
|
}
|
|
|
|
QByteArray fileEncryptionKey = handler->createFileEncryptionKey(paddedUserPassword);
|
|
QByteArray U = handler->createEntryValueU_r234(fileEncryptionKey);
|
|
handler->m_U = U;
|
|
|
|
break;
|
|
}
|
|
|
|
case 6:
|
|
{
|
|
PDFStandardSecurityHandler::UserOwnerData_r6 userData;
|
|
PDFStandardSecurityHandler::UserOwnerData_r6 ownerData;
|
|
|
|
QRandomGenerator randomNumberGenerator = QRandomGenerator::securelySeeded();
|
|
|
|
// Generate file encryption key
|
|
handler->m_authorizationData.fileEncryptionKey = generateRandomByteArray(randomNumberGenerator, 32);
|
|
handler->m_authorizationData.authorizationResult = PDFSecurityHandler::AuthorizationResult::OwnerAuthorized;
|
|
|
|
// Compute m_U entry
|
|
userData.keySalt = generateRandomByteArray(randomNumberGenerator, 8);
|
|
userData.validationSalt = generateRandomByteArray(randomNumberGenerator, 8);
|
|
userData.hash = handler->createHash_r6(adjustedUserPassword + userData.validationSalt, adjustedUserPassword, false);
|
|
handler->m_U = userData.hash + userData.validationSalt + userData.keySalt;
|
|
|
|
// Compute m_UE entry
|
|
QByteArray userFileEncryptionKeyInputData = adjustedUserPassword + userData.keySalt;
|
|
QByteArray userFileEncryptionKey = handler->createHash_r6(userFileEncryptionKeyInputData, adjustedUserPassword, false);
|
|
|
|
Q_ASSERT(userFileEncryptionKey.size() == 32);
|
|
AES_KEY userKey = { };
|
|
AES_set_encrypt_key(convertByteArrayToUcharPtr(userFileEncryptionKey), userFileEncryptionKey.size() * 8, &userKey);
|
|
unsigned char aesUserInitializationVector[AES_BLOCK_SIZE] = { };
|
|
handler->m_UE.resize(handler->m_authorizationData.fileEncryptionKey.size());
|
|
unsigned char* userInputBuffer = convertByteArrayToUcharPtr(handler->m_authorizationData.fileEncryptionKey);
|
|
unsigned char* userTargetBuffer = convertByteArrayToUcharPtr(handler->m_UE);
|
|
AES_cbc_encrypt(userInputBuffer, userTargetBuffer, handler->m_UE.size(), &userKey, aesUserInitializationVector, AES_ENCRYPT);
|
|
|
|
// Compute m_O entry
|
|
ownerData.keySalt = generateRandomByteArray(randomNumberGenerator, 8);
|
|
ownerData.validationSalt = generateRandomByteArray(randomNumberGenerator, 8);
|
|
ownerData.hash = handler->createHash_r6(adjustedOwnerPassword + ownerData.validationSalt + handler->m_U, adjustedOwnerPassword, true);
|
|
handler->m_O = ownerData.hash + ownerData.validationSalt + ownerData.keySalt;
|
|
|
|
// Compute m_OE entry
|
|
QByteArray ownerFileEncryptionKeyInputData = adjustedOwnerPassword + ownerData.keySalt + handler->m_U;
|
|
QByteArray ownerFileEncryptionKey = handler->createHash_r6(ownerFileEncryptionKeyInputData, adjustedOwnerPassword, true);
|
|
|
|
AES_KEY ownerKey = { };
|
|
AES_set_encrypt_key(convertByteArrayToUcharPtr(ownerFileEncryptionKey), ownerFileEncryptionKey.size() * 8, &ownerKey);
|
|
unsigned char aesOwnerInitializationVector[AES_BLOCK_SIZE] = { };
|
|
handler->m_OE.resize(handler->m_authorizationData.fileEncryptionKey.size());
|
|
unsigned char* ownerInputBuffer = convertByteArrayToUcharPtr(handler->m_authorizationData.fileEncryptionKey);
|
|
unsigned char* ownerTargetBuffer = convertByteArrayToUcharPtr(handler->m_OE);
|
|
AES_cbc_encrypt(ownerInputBuffer, ownerTargetBuffer, handler->m_OE.size(), &ownerKey, aesOwnerInitializationVector, AES_ENCRYPT);
|
|
|
|
// Perms entry
|
|
handler->m_Perms = QByteArray(AES_BLOCK_SIZE, char(0));
|
|
unsigned char* permsData = convertByteArrayToUcharPtr(handler->m_Perms);
|
|
permsData[0] = handler->m_permissions & 0xFF;
|
|
permsData[1] = (handler->m_permissions >> 8) & 0xFF;
|
|
permsData[2] = (handler->m_permissions >> 16) & 0xFF;
|
|
permsData[3] = (handler->m_permissions >> 24) & 0xFF;
|
|
permsData[4] = 0xFF;
|
|
permsData[5] = 0xFF;
|
|
permsData[6] = 0xFF;
|
|
permsData[7] = 0xFF;
|
|
permsData[8] = handler->m_encryptMetadata ? 'T' : 'F';
|
|
permsData[9] = 'a';
|
|
permsData[10] = 'd';
|
|
permsData[11] = 'b';
|
|
permsData[12] = randomNumberGenerator.generate() & 0xFF;
|
|
permsData[13] = randomNumberGenerator.generate() & 0xFF;
|
|
permsData[14] = randomNumberGenerator.generate() & 0xFF;
|
|
permsData[15] = randomNumberGenerator.generate() & 0xFF;
|
|
|
|
Q_ASSERT(handler->m_Perms.size() == AES_BLOCK_SIZE);
|
|
AES_KEY key = { };
|
|
AES_set_encrypt_key(convertByteArrayToUcharPtr(handler->m_authorizationData.fileEncryptionKey), handler->m_authorizationData.fileEncryptionKey.size() * 8, &key);
|
|
AES_ecb_encrypt(convertByteArrayToUcharPtr(handler->m_Perms), convertByteArrayToUcharPtr(handler->m_Perms), &key, AES_ENCRYPT);
|
|
|
|
break;
|
|
}
|
|
|
|
default:
|
|
{
|
|
Q_ASSERT(false);
|
|
break;
|
|
}
|
|
}
|
|
|
|
bool firstTry = true;
|
|
handler->authenticate([&settings, &firstTry](bool* b) { *b = firstTry; firstTry = false; return settings.ownerPassword; }, true);
|
|
Q_ASSERT(handler->getAuthorizationResult() == PDFSecurityHandler::AuthorizationResult::OwnerAuthorized);
|
|
return PDFSecurityHandlerPointer(handler);
|
|
}
|
|
|
|
int PDFSecurityHandlerFactory::getPasswordOptimalEntropy()
|
|
{
|
|
return 128;
|
|
}
|
|
|
|
int PDFSecurityHandlerFactory::getPasswordEntropy(const QString& password, Algorithm algorithm)
|
|
{
|
|
if (algorithm == None)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
QByteArray adjustedPassword = PDFStandardSecurityHandler::adjustPassword(password, getRevisionFromAlgorithm(algorithm));
|
|
|
|
if (adjustedPassword.isEmpty())
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
const int length = adjustedPassword.length();
|
|
std::sort(adjustedPassword.begin(), adjustedPassword.end());
|
|
|
|
int charCount = 0;
|
|
char lastChar = adjustedPassword.front();
|
|
PDFReal entropy = 0.0;
|
|
|
|
for (int i = 0; i < length; ++i)
|
|
{
|
|
const char currentChar = adjustedPassword[i];
|
|
|
|
if (currentChar == lastChar)
|
|
{
|
|
++charCount;
|
|
}
|
|
else
|
|
{
|
|
const PDFReal probability = PDFReal(charCount) / PDFReal(length);
|
|
entropy += -probability * std::log2(probability);
|
|
|
|
charCount = 1;
|
|
lastChar = currentChar;
|
|
}
|
|
}
|
|
|
|
// Jakub Melka: last character
|
|
const PDFReal probability = PDFReal(charCount) / PDFReal(length);
|
|
entropy += -probability * std::log2(probability);
|
|
|
|
return entropy * length;
|
|
}
|
|
|
|
int PDFSecurityHandlerFactory::getRevisionFromAlgorithm(Algorithm algorithm)
|
|
{
|
|
switch (algorithm)
|
|
{
|
|
case None:
|
|
return 0;
|
|
|
|
case RC4:
|
|
return 4;
|
|
|
|
case AES_128:
|
|
return 4;
|
|
|
|
case AES_256:
|
|
return 6;
|
|
|
|
default:
|
|
Q_ASSERT(false);
|
|
break;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
QByteArray PDFSecurityHandlerFactory::generateRandomByteArray(QRandomGenerator& generator, int size)
|
|
{
|
|
QByteArray ba;
|
|
ba.reserve(size);
|
|
|
|
for (int i = 0; i < size; ++i)
|
|
{
|
|
ba.push_back(static_cast<char>(generator.generate()));
|
|
}
|
|
|
|
return ba;
|
|
}
|
|
|
|
bool PDFSecurityHandlerFactory::validate(const SecuritySettings& settings, QString* errorMessage)
|
|
{
|
|
switch (settings.algorithm)
|
|
{
|
|
case pdf::PDFSecurityHandlerFactory::RC4:
|
|
case pdf::PDFSecurityHandlerFactory::AES_128:
|
|
{
|
|
QString invalidCharacters;
|
|
|
|
if (!PDFEncoding::canConvertToEncoding(settings.userPassword, PDFEncoding::Encoding::PDFDoc, &invalidCharacters))
|
|
{
|
|
if (errorMessage)
|
|
{
|
|
Q_ASSERT(!invalidCharacters.isEmpty());
|
|
*errorMessage = tr("User password contains invalid characters: %1.").arg(invalidCharacters);
|
|
}
|
|
return false;
|
|
}
|
|
|
|
if (!PDFEncoding::canConvertToEncoding(settings.ownerPassword, PDFEncoding::Encoding::PDFDoc, &invalidCharacters))
|
|
{
|
|
if (errorMessage)
|
|
{
|
|
Q_ASSERT(!invalidCharacters.isEmpty());
|
|
*errorMessage = tr("Owner password contains invalid characters: %1.").arg(invalidCharacters);
|
|
}
|
|
return false;
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
case pdf::PDFSecurityHandlerFactory::None:
|
|
case pdf::PDFSecurityHandlerFactory::AES_256:
|
|
break;
|
|
|
|
default:
|
|
Q_ASSERT(false);
|
|
break;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
|
|
PDFSecurityHandler* PDFPublicKeySecurityHandler::clone() const
|
|
{
|
|
return new PDFPublicKeySecurityHandler(*this);
|
|
}
|
|
|
|
PDFSecurityHandler::AuthorizationResult PDFPublicKeySecurityHandler::authenticate(const std::function<QString (bool*)>& getPasswordCallback, bool authorizeOwnerOnly)
|
|
{
|
|
// Clear the authorization data
|
|
m_authorizationData = AuthorizationData();
|
|
|
|
if (authorizeOwnerOnly)
|
|
{
|
|
return AuthorizationResult::Failed;
|
|
}
|
|
|
|
switch (m_keyLength)
|
|
{
|
|
case 128:
|
|
case 256:
|
|
break;
|
|
|
|
default:
|
|
return AuthorizationResult::Failed;
|
|
}
|
|
|
|
bool passwordObtained = true;
|
|
constexpr int revision = 0;
|
|
QByteArray password = adjustPassword(getPasswordCallback(&passwordObtained), revision);
|
|
|
|
QFileInfoList certificates = PDFCertificateManager::getCertificates();
|
|
if (certificates.isEmpty())
|
|
{
|
|
return AuthorizationResult::Failed;
|
|
}
|
|
|
|
std::vector<openssl_ptr<PKCS7>> recipients;
|
|
|
|
for (const QByteArray& recipient : m_filterDefault.recipients)
|
|
{
|
|
const unsigned char* data = convertByteArrayToUcharPtr(recipient);
|
|
if (PKCS7* pkcs7 = d2i_PKCS7(nullptr, &data, recipient.size()))
|
|
{
|
|
recipients.emplace_back(pkcs7, PKCS7_free);
|
|
}
|
|
}
|
|
|
|
while (passwordObtained)
|
|
{
|
|
// We will iterate trough all certificates
|
|
for (const QFileInfo& certificateFileInfo : certificates)
|
|
{
|
|
if (!PDFCertificateManager::isCertificateValid(certificateFileInfo.absoluteFilePath(), password))
|
|
{
|
|
continue;
|
|
}
|
|
|
|
QFile file(certificateFileInfo.absoluteFilePath());
|
|
if (file.open(QFile::ReadOnly))
|
|
{
|
|
QByteArray data = file.readAll();
|
|
file.close();
|
|
|
|
openssl_ptr<BIO> pksBuffer(BIO_new(BIO_s_mem()), &BIO_free_all);
|
|
BIO_write(pksBuffer.get(), data.constData(), data.length());
|
|
|
|
openssl_ptr<PKCS12> pkcs12(d2i_PKCS12_bio(pksBuffer.get(), nullptr), &PKCS12_free);
|
|
if (pkcs12)
|
|
{
|
|
const char* passwordPointer = nullptr;
|
|
if (!password.isEmpty())
|
|
{
|
|
passwordPointer = password.constData();
|
|
}
|
|
|
|
EVP_PKEY* keyPtr = nullptr;
|
|
X509* certificatePtr = nullptr;
|
|
STACK_OF(X509)* certificatesPtr = nullptr;
|
|
|
|
// Parse PKCS12 with password
|
|
bool isParsed = PKCS12_parse(pkcs12.get(), passwordPointer, &keyPtr, &certificatePtr, &certificatesPtr) == 1;
|
|
|
|
if (!isParsed)
|
|
{
|
|
continue;
|
|
}
|
|
|
|
openssl_ptr<EVP_PKEY> key(keyPtr, EVP_PKEY_free);
|
|
openssl_ptr<X509> certificate(certificatePtr, X509_free);
|
|
openssl_ptr<STACK_OF(X509)> certificates(certificatesPtr, sk_X509_free);
|
|
|
|
for (const auto& recipientItem : recipients)
|
|
{
|
|
PKCS7* pkcs7 = recipientItem.get();
|
|
|
|
openssl_ptr<BIO> dataBuffer(BIO_new(BIO_s_mem()), BIO_free_all);
|
|
if (PKCS7_decrypt(pkcs7, keyPtr, certificatePtr, dataBuffer.get(), 0) == 1)
|
|
{
|
|
BUF_MEM* memoryBuffer = nullptr;
|
|
BIO_get_mem_ptr(dataBuffer.get(), &memoryBuffer);
|
|
|
|
// Acc. to chapter 7.6.5.3 - decrypted data
|
|
QByteArray decryptedData(memoryBuffer->data, int(memoryBuffer->length));
|
|
|
|
// Calculate file encryption key
|
|
EVP_MD_CTX* context = EVP_MD_CTX_new();
|
|
Q_ASSERT(context);
|
|
|
|
switch (m_keyLength)
|
|
{
|
|
case 128:
|
|
EVP_DigestInit(context, EVP_sha1());
|
|
break;
|
|
|
|
case 256:
|
|
EVP_DigestInit(context, EVP_sha256());
|
|
break;
|
|
|
|
default:
|
|
Q_ASSERT(false);
|
|
EVP_DigestInit(context, EVP_sha256());
|
|
break;
|
|
}
|
|
|
|
QByteArray seed = decryptedData.left(20);
|
|
|
|
// 7.6.5.3 a)
|
|
EVP_DigestUpdate(context, seed.constData(), seed.size());
|
|
|
|
// 7.6.5.3 b)
|
|
for (const QByteArray& recipient : m_filterDefault.recipients)
|
|
{
|
|
EVP_DigestUpdate(context, recipient.constData(), recipient.size());
|
|
}
|
|
|
|
// 7.6.5.3 c)
|
|
if (!isMetadataEncrypted())
|
|
{
|
|
constexpr uint32_t value = 0xFFFFFFFF;
|
|
EVP_DigestUpdate(context, &value, sizeof(value));
|
|
}
|
|
|
|
unsigned int size = EVP_MD_size(EVP_MD_CTX_md(context));
|
|
QByteArray digestBuffer(size, char());
|
|
|
|
EVP_DigestFinal_ex(context, convertByteArrayToUcharPtr(digestBuffer), &size);
|
|
EVP_MD_CTX_free(context);
|
|
|
|
m_authorizationData.fileEncryptionKey = digestBuffer.left(m_keyLength / 8);
|
|
m_authorizationData.authorizationResult = AuthorizationResult::UserAuthorized;
|
|
return AuthorizationResult::UserAuthorized;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
password = adjustPassword(getPasswordCallback(&passwordObtained), revision);
|
|
}
|
|
|
|
return AuthorizationResult::Cancelled;
|
|
}
|
|
|
|
bool PDFPublicKeySecurityHandler::isMetadataEncrypted() const
|
|
{
|
|
return true;
|
|
}
|
|
|
|
bool PDFPublicKeySecurityHandler::isAllowed(Permission permission) const
|
|
{
|
|
return false;
|
|
}
|
|
|
|
PDFObject PDFPublicKeySecurityHandler::createEncryptionDictionaryObject() const
|
|
{
|
|
return PDFObject();
|
|
}
|
|
|
|
} // namespace pdf
|