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PDF4QT
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Public key encryption: bugfixing

This commit is contained in:
Jakub Melka 2022-06-26 18:46:53 +02:00
parent ac039a1539
commit 3456977f22
3 changed files with 106 additions and 11 deletions
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80
Pdf4QtLib/sources/pdfsecurityhandler.cpp
View File

@ -491,7 +491,7 @@ PDFSecurityHandlerPointer PDFSecurityHandler::createSecurityHandler(const PDFObj
return handler;
}
void PDFSecurityHandler::fillEncryptionDictionary(PDFObjectFactory& factory) const
void PDFSecurityHandler::fillEncryptionDictionary(PDFObjectFactory& factory, bool publicKeyHandler) const
{
factory.beginDictionaryItem("V");
factory << PDFInteger(m_V);
@ -585,10 +585,37 @@ void PDFSecurityHandler::fillEncryptionDictionary(PDFObjectFactory& factory) con
factory.endDictionaryItem();
// Jakub Melka: Warning! According to the PDF 2.0 specification,
// standard security handler expresses key length in bytes (32
// for 256 bit key), but public key security handler in bits (value
// 256 for 256 bit key).
factory.beginDictionaryItem("Length");
if (!publicKeyHandler)
{
factory << cryptFilter.second.keyLength;
}
else
{
factory << PDFInteger(cryptFilter.second.keyLength * 8);
}
factory.endDictionaryItem();
if (publicKeyHandler)
{
factory.beginDictionaryItem("Recipients");
factory.beginArray();
for (const auto& recipient : cryptFilter.second.recipients)
{
factory << WrapString(recipient);
}
factory.endArray();
factory.endDictionaryItem();
factory.beginDictionaryItem("EncryptMetadata");
factory << cryptFilter.second.encryptMetadata;
factory.endDictionaryItem();
}
factory.endDictionary();
factory.endDictionaryItem();
@ -1383,7 +1410,7 @@ PDFObject PDFStandardSecurityHandler::createEncryptionDictionaryObject() const
factory.beginDictionary();
fillEncryptionDictionary(factory);
fillEncryptionDictionary(factory, false);
factory.beginDictionaryItem("Filter");
factory << WrapName("Standard");
@ -1975,7 +2002,11 @@ PDFSecurityHandlerPointer PDFSecurityHandlerFactory::createSecurityHandler(const
BIO_write(dataToBeSigned.get(), randomKey.data(), randomKey.length());
BIO_write(dataToBeSigned.get(), &permissions, sizeof(permissions));
openssl_ptr<PKCS7> pkcs7(PKCS7_sign(certificate.get(), key.get(), certificates.get(), dataToBeSigned.get(), PKCS7_BINARY), PKCS7_free);
openssl_ptr<STACK_OF(X509)> recipientCertificates(sk_X509_new_null(), sk_X509_free);
sk_X509_push(recipientCertificates.get(), certificate.get());
openssl_ptr<PKCS7> pkcs7(PKCS7_encrypt(recipientCertificates.get(), dataToBeSigned.get(), EVP_aes_256_cbc(), PKCS7_BINARY), PKCS7_free);
if (pkcs7)
{
openssl_ptr<BIO> storedData(BIO_new(BIO_s_mem()), BIO_free_all);
@ -2020,7 +2051,22 @@ PDFSecurityHandlerPointer PDFSecurityHandlerFactory::createSecurityHandler(const
}
handler->m_filterDefault.encryptMetadata = settings.encryptContents == All;
if (standardHandler)
{
handler->m_cryptFilters["StdCF"] = handler->m_filterDefault;
}
if (publicKeyHandler)
{
if (settings.encryptContents != EmbeddedFiles)
{
handler->m_cryptFilters["DefaultCryptFilter"] = handler->m_filterDefault;
}
else
{
handler->m_cryptFilters["DefEmbeddedFile"] = handler->m_filterDefault;
}
}
if (standardHandler)
{
@ -2531,7 +2577,33 @@ bool PDFPublicKeySecurityHandler::isAllowed(Permission permission) const
PDFObject PDFPublicKeySecurityHandler::createEncryptionDictionaryObject() const
{
return PDFObject();
PDFObjectFactory factory;
factory.beginDictionary();
fillEncryptionDictionary(factory, true);
factory.beginDictionaryItem("Filter");
factory << WrapName("Adobe.PubSec");
factory.endDictionaryItem();
factory.beginDictionaryItem("SubFilter");
factory << WrapName("adbe.pkcs7.s5");
factory.endDictionaryItem();
factory.beginDictionaryItem("P");
factory << PDFInteger(int32_t(m_permissions));
factory.endDictionaryItem();
// Jakub Melka: 131105 is mysterious value set by Adobe Acrobat Pro
// when using public key security
factory.beginDictionaryItem("R");
factory << PDFInteger(131105);
factory.endDictionaryItem();
factory.endDictionary();
return factory.takeObject();
}
} // namespace pdf

2
Pdf4QtLib/sources/pdfsecurityhandler.h
View File

@ -215,7 +215,7 @@ protected:
/// Fills encryption dictionary with basic data
/// \param factory Factory
void fillEncryptionDictionary(PDFObjectFactory& factory) const;
void fillEncryptionDictionary(PDFObjectFactory& factory, bool publicKeyHandler) const;
/// Version of the encryption, shall be a number from 1 to 5, according the
/// PDF specification. Other values are invalid.

25
Pdf4QtViewer/pdfprogramcontroller.cpp
View File

@ -1211,13 +1211,36 @@ void PDFProgramController::onActionEncryptionTriggered()
// Jakub Melka: If we changed encryption (password), recheck, that user doesn't
// forgot (or accidentally entered wrong) password. So, we require owner authentization
// to continue.
if (updatedSecurityHandler->getMode() != pdf::EncryptionMode::None)
switch (updatedSecurityHandler->getMode())
{
case pdf::EncryptionMode::Standard:
{
if (updatedSecurityHandler->authenticate(queryPassword, true) != pdf::PDFSecurityHandler::AuthorizationResult::OwnerAuthorized)
{
QMessageBox::critical(m_mainWindow, QApplication::applicationDisplayName(), tr("Reauthorization is required to change document encryption."));
return;
}
break;
}
case pdf::EncryptionMode::PublicKey:
{
if (updatedSecurityHandler->authenticate(queryPassword, false) != pdf::PDFSecurityHandler::AuthorizationResult::UserAuthorized)
{
QMessageBox::critical(m_mainWindow, QApplication::applicationDisplayName(), tr("Reauthorization is required to change document encryption."));
return;
}
break;
}
case pdf::EncryptionMode::None:
break;
default:
Q_ASSERT(false);
break;
}
pdf::PDFDocumentBuilder builder(m_pdfDocument.data());