Correctly set KDBX envelope version

Shows a warning when trying to open with a newer minor version than what is currently supported.

We always try to save with the lowest KDBX version possible for maximum compatibility.

share/translations/keepassxc_en.ts

@@ -1535,6 +1535,28 @@ If you do not have a key file, please leave the field empty.</source>
         <source>Please present or touch your YubiKey to continue…</source>
         <translation type="unfinished"></translation>
     </message>
+    <message>
+        <source>Database Version Mismatch</source>
+        <translation type="unfinished"></translation>
+    </message>
+    <message>
+        <source>The database you are trying to open was most likely
+created by a newer version of KeePassXC.
+
+You can try to open it anyway, but it may be incomplete
+and saving any changes may incur data loss.
+
+We recommend you update your KeePassXC installation.</source>
+        <translation type="unfinished"></translation>
+    </message>
+    <message>
+        <source>Open database anyway</source>
+        <translation type="unfinished"></translation>
+    </message>
+    <message>
+        <source>Database unlock canceled.</source>
+        <translation type="unfinished"></translation>
+    </message>
 </context>
 <context>
     <name>DatabaseSettingWidgetMetaData</name>
@@ -1808,18 +1830,6 @@ Are you sure you want to continue without a password?</translation>
         <source>Database format:</source>
         <translation>Database format:</translation>
     </message>
-    <message>
-        <source>This is only important if you need to use your database with other programs.</source>
-        <translation>This is only important if you need to use your database with other programs.</translation>
-    </message>
-    <message>
-        <source>KDBX 4.0 (recommended)</source>
-        <translation>KDBX 4.0 (recommended)</translation>
-    </message>
-    <message>
-        <source>KDBX 3.1</source>
-        <translation>KDBX 3.1</translation>
-    </message>
     <message>
         <source>unchanged</source>
         <comment>Database decryption time is unchanged</comment>
@@ -1919,6 +1929,22 @@ If you keep this number, your database may take hours, days, or even longer to o
 If you keep this number, your database will not be protected from brute force attacks.</source>
         <translation type="unfinished"></translation>
     </message>
+    <message>
+        <source>Format cannot be changed: Your database uses KDBX 4 features</source>
+        <translation type="unfinished"></translation>
+    </message>
+    <message>
+        <source>Unless you need to open your database with other programs, always use the latest format.</source>
+        <translation type="unfinished"></translation>
+    </message>
+    <message>
+        <source>KDBX 4 (recommended)</source>
+        <translation type="unfinished">KDBX 4.0 (recommended) {4 ?}</translation>
+    </message>
+    <message>
+        <source>KDBX 3</source>
+        <translation type="unfinished">KDBX 3</translation>
+    </message>
 </context>
 <context>
     <name>DatabaseSettingsWidgetFdoSecrets</name>
@@ -6523,10 +6549,6 @@ Available commands:
         <source>AES-KDF (KDBX 4)</source>
         <translation>AES-KDF (KDBX 4)</translation>
     </message>
-    <message>
-        <source>AES-KDF (KDBX 3.1)</source>
-        <translation>AES-KDF (KDBX 3.1)</translation>
-    </message>
     <message>
         <source>Invalid Settings</source>
         <comment>TOTP</comment>
@@ -7498,6 +7520,10 @@ Please consider generating a new key file.</source>
         <source>Attachments:</source>
         <translation type="unfinished"></translation>
     </message>
+    <message>
+        <source>AES-KDF (KDBX 3)</source>
+        <translation type="unfinished">AES-KDF (KDBX 3.1) {3)?}</translation>
+    </message>
 </context>
 <context>
     <name>QtIOCompressor</name>

src/core/Database.cpp

@@ -163,6 +163,27 @@ bool Database::open(const QString& filePath, QSharedPointer<const CompositeKey>
     return true;
 }
 
+/**
+ * KDBX format version.
+ */
+quint32 Database::formatVersion() const
+{
+    return m_data.formatVersion;
+}
+
+void Database::setFormatVersion(quint32 version)
+{
+    m_data.formatVersion = version;
+}
+
+/**
+ * Whether the KDBX minor version is greater than the newest supported.
+ */
+bool Database::hasMinorVersionMismatch() const
+{
+    return m_data.formatVersion > KeePass2::FILE_VERSION_MAX;
+}
+
 bool Database::isSaving()
 {
     bool locked = m_saveMutex.tryLock();
@@ -935,6 +956,7 @@ void Database::setKdf(QSharedPointer<Kdf> kdf)
 {
     Q_ASSERT(!m_data.isReadOnly);
     m_data.kdf = std::move(kdf);
+    setFormatVersion(KeePass2Writer::kdbxVersionRequired(this, true, m_data.kdf.isNull()));
 }
 
 bool Database::changeKdf(const QSharedPointer<Kdf>& kdf)

src/core/Database.h

@@ -87,6 +87,10 @@ class Database : public ModifiableObject
     bool extract(QByteArray&, QString* error = nullptr);
     bool import(const QString& xmlExportPath, QString* error = nullptr);
 
+    quint32 formatVersion() const;
+    void setFormatVersion(quint32 version);
+    bool hasMinorVersionMismatch() const;
+
     void releaseData();
 
     bool isInitialized() const;
@@ -166,6 +170,7 @@ public slots:
 private:
     struct DatabaseData
     {
+        quint32 formatVersion = 0;
         QString filePath;
         bool isReadOnly = false;
         QUuid cipher = KeePass2::CIPHER_AES256;

src/format/Kdbx3Reader.cpp

@@ -34,7 +34,7 @@ bool Kdbx3Reader::readDatabaseImpl(QIODevice* device,
                                    QSharedPointer<const CompositeKey> key,
                                    Database* db)
 {
-    Q_ASSERT(m_kdbxVersion <= KeePass2::FILE_VERSION_3_1);
+    Q_ASSERT((db->formatVersion() & KeePass2::FILE_VERSION_CRITICAL_MASK) <= KeePass2::FILE_VERSION_3);
 
     if (hasError()) {
         return false;
@@ -120,7 +120,7 @@ bool Kdbx3Reader::readDatabaseImpl(QIODevice* device,
         return false;
     }
 
-    Q_ASSERT(!xmlReader.headerHash().isEmpty() || m_kdbxVersion < KeePass2::FILE_VERSION_3_1);
+    Q_ASSERT(!xmlReader.headerHash().isEmpty() || db->formatVersion() < KeePass2::FILE_VERSION_3_1);
 
     if (!xmlReader.headerHash().isEmpty()) {
         QByteArray headerHash = CryptoHash::hash(headerData, CryptoHash::Sha256);

src/format/Kdbx3Writer.cpp

@@ -68,7 +68,7 @@ bool Kdbx3Writer::writeDatabase(QIODevice* device, Database* db)
     QBuffer header;
     header.open(QIODevice::WriteOnly);
 
-    writeMagicNumbers(&header, KeePass2::SIGNATURE_1, KeePass2::SIGNATURE_2, formatVersion());
+    writeMagicNumbers(&header, KeePass2::SIGNATURE_1, KeePass2::SIGNATURE_2, db->formatVersion());
 
     CHECK_RETURN_FALSE(writeHeaderField<quint16>(&header, KeePass2::HeaderFieldID::CipherID, db->cipher().toRfc4122()));
     CHECK_RETURN_FALSE(
@@ -137,7 +137,7 @@ bool Kdbx3Writer::writeDatabase(QIODevice* device, Database* db)
         return false;
     }
 
-    KdbxXmlWriter xmlWriter(formatVersion());
+    KdbxXmlWriter xmlWriter(db->formatVersion());
     xmlWriter.writeDatabase(outputDevice, db, &randomStream, headerHash);
 
     // Explicitly close/reset streams so they are flushed and we can detect
@@ -161,8 +161,3 @@ bool Kdbx3Writer::writeDatabase(QIODevice* device, Database* db)
 
     return true;
 }
-
-quint32 Kdbx3Writer::formatVersion()
-{
-    return KeePass2::FILE_VERSION_3_1;
-}

src/format/Kdbx3Writer.h

@@ -29,7 +29,6 @@ class Kdbx3Writer : public KdbxWriter
 
 public:
     bool writeDatabase(QIODevice* device, Database* db) override;
-    quint32 formatVersion() override;
 };
 
 #endif // KEEPASSX_KDBX3WRITER_H

src/format/Kdbx4Reader.cpp

@@ -36,7 +36,7 @@ bool Kdbx4Reader::readDatabaseImpl(QIODevice* device,
                                    QSharedPointer<const CompositeKey> key,
                                    Database* db)
 {
-    Q_ASSERT(m_kdbxVersion == KeePass2::FILE_VERSION_4);
+    Q_ASSERT((db->formatVersion() & KeePass2::FILE_VERSION_CRITICAL_MASK) == KeePass2::FILE_VERSION_4);
 
     m_binaryPool.clear();
 

src/format/Kdbx4Writer.cpp

@@ -66,7 +66,7 @@ bool Kdbx4Writer::writeDatabase(QIODevice* device, Database* db)
         QBuffer header;
         header.open(QIODevice::WriteOnly);
 
-        writeMagicNumbers(&header, KeePass2::SIGNATURE_1, KeePass2::SIGNATURE_2, formatVersion());
+        writeMagicNumbers(&header, KeePass2::SIGNATURE_1, KeePass2::SIGNATURE_2, db->formatVersion());
 
         CHECK_RETURN_FALSE(
             writeHeaderField<quint32>(&header, KeePass2::HeaderFieldID::CipherID, db->cipher().toRfc4122()));
@@ -166,7 +166,7 @@ bool Kdbx4Writer::writeDatabase(QIODevice* device, Database* db)
         return false;
     }
 
-    KdbxXmlWriter xmlWriter(formatVersion());
+    KdbxXmlWriter xmlWriter(db->formatVersion());
     xmlWriter.writeDatabase(outputDevice, db, &randomStream, headerHash);
 
     // Explicitly close/reset streams so they are flushed and we can detect
@@ -306,8 +306,3 @@ bool Kdbx4Writer::serializeVariantMap(const QVariantMap& map, QByteArray& output
     CHECK_RETURN_FALSE(buf.write(endBytes) == 1);
     return true;
 }
-
-quint32 Kdbx4Writer::formatVersion()
-{
-    return KeePass2::FILE_VERSION_4;
-}

src/format/Kdbx4Writer.h

@@ -29,7 +29,6 @@ class Kdbx4Writer : public KdbxWriter
 
 public:
     bool writeDatabase(QIODevice* device, Database* db) override;
-    quint32 formatVersion() override;
 
 private:
     bool writeInnerHeaderField(QIODevice* device, KeePass2::InnerHeaderFieldID fieldId, const QByteArray& data);

src/format/KdbxReader.cpp

@@ -74,14 +74,12 @@ bool KdbxReader::readDatabase(QIODevice* device, QSharedPointer<const CompositeK
     headerStream.open(QIODevice::ReadOnly);
 
     // read KDBX magic numbers
-    quint32 sig1, sig2;
-    if (!readMagicNumbers(&headerStream, sig1, sig2, m_kdbxVersion)) {
+    quint32 sig1, sig2, version;
+    if (!readMagicNumbers(&headerStream, sig1, sig2, version)) {
         return false;
     }
     m_kdbxSignature = qMakePair(sig1, sig2);
-
-    // mask out minor version
-    m_kdbxVersion &= KeePass2::FILE_VERSION_CRITICAL_MASK;
+    m_db->setFormatVersion(version);
 
     // read header fields
     while (readHeaderField(headerStream, m_db) && !hasError()) {

src/format/KdbxReader.h

@@ -83,8 +83,6 @@ class KdbxReader
 
     void raiseError(const QString& errorMessage);
 
-    quint32 m_kdbxVersion = 0;
-
     QByteArray m_masterSeed;
     QByteArray m_encryptionIV;
     QByteArray m_streamStartBytes;

src/format/KdbxWriter.cpp

@@ -71,7 +71,7 @@ void KdbxWriter::extractDatabase(QByteArray& xmlOutput, Database* db)
     QBuffer buffer;
     buffer.setBuffer(&xmlOutput);
     buffer.open(QIODevice::WriteOnly);
-    KdbxXmlWriter writer(formatVersion());
+    KdbxXmlWriter writer(db->formatVersion());
     writer.disableInnerStreamProtection(true);
     writer.writeDatabase(&buffer, db);
 }

src/format/KdbxWriter.h

@@ -52,11 +52,6 @@ class KdbxWriter
      */
     virtual bool writeDatabase(QIODevice* device, Database* db) = 0;
 
-    /**
-     * Get the database format version for the writer.
-     */
-    virtual quint32 formatVersion() = 0;
-
     void extractDatabase(QByteArray& xmlOutput, Database* db);
 
     bool hasError() const;

src/format/KdbxXmlWriter.cpp

@@ -166,7 +166,7 @@ void KdbxXmlWriter::writeIcon(const QUuid& uuid, const Metadata::CustomIconData&
     m_xml.writeStartElement("Icon");
 
     writeUuid("UUID", uuid);
-    if (m_kdbxVersion >= KeePass2::FILE_VERSION_4) {
+    if (m_kdbxVersion >= KeePass2::FILE_VERSION_4_1) {
         if (!iconData.name.isEmpty()) {
             writeString("Name", iconData.name);
         }
@@ -243,7 +243,7 @@ void KdbxXmlWriter::writeCustomDataItem(const QString& key,
 
     writeString("Key", key);
     writeString("Value", item.value);
-    if (writeLastModified && m_kdbxVersion >= KeePass2::FILE_VERSION_4 && item.lastModified.isValid()) {
+    if (writeLastModified && m_kdbxVersion >= KeePass2::FILE_VERSION_4_1 && item.lastModified.isValid()) {
         writeDateTime("LastModificationTime", item.lastModified);
     }
 
@@ -291,9 +291,9 @@ void KdbxXmlWriter::writeGroup(const Group* group)
 
     if (m_kdbxVersion >= KeePass2::FILE_VERSION_4) {
         writeCustomData(group->customData());
-        if (!group->previousParentGroupUuid().isNull()) {
-            writeUuid("PreviousParentGroup", group->previousParentGroupUuid());
-        }
+    }
+    if (m_kdbxVersion >= KeePass2::FILE_VERSION_4_1 && !group->previousParentGroupUuid().isNull()) {
+        writeUuid("PreviousParentGroup", group->previousParentGroupUuid());
     }
 
     const QList<Entry*>& entryList = group->entries();
@@ -363,7 +363,7 @@ void KdbxXmlWriter::writeEntry(const Entry* entry)
     writeString("Tags", entry->tags());
     writeTimes(entry->timeInfo());
 
-    if (m_kdbxVersion >= KeePass2::FILE_VERSION_4) {
+    if (m_kdbxVersion >= KeePass2::FILE_VERSION_4_1) {
         if (entry->excludeFromReports()) {
             writeBool("QualityCheck", false);
         }

src/format/KeePass2.cpp

@@ -56,7 +56,7 @@ const QList<QPair<QUuid, QString>> KeePass2::KDFS{
     qMakePair(KeePass2::KDF_ARGON2D, QObject::tr("Argon2d (KDBX 4 – recommended)")),
     qMakePair(KeePass2::KDF_ARGON2ID, QObject::tr("Argon2id (KDBX 4)")),
     qMakePair(KeePass2::KDF_AES_KDBX4, QObject::tr("AES-KDF (KDBX 4)")),
-    qMakePair(KeePass2::KDF_AES_KDBX3, QObject::tr("AES-KDF (KDBX 3.1)"))};
+    qMakePair(KeePass2::KDF_AES_KDBX3, QObject::tr("AES-KDF (KDBX 3)"))};
 
 QByteArray KeePass2::hmacKey(const QByteArray& masterSeed, const QByteArray& transformedMasterKey)
 {

src/format/KeePass2.h

@@ -31,16 +31,18 @@ namespace KeePass2
     constexpr quint32 SIGNATURE_2 = 0xB54BFB67;
 
     constexpr quint32 FILE_VERSION_CRITICAL_MASK = 0xFFFF0000;
+    constexpr quint32 FILE_VERSION_4_1 = 0x00040001;
     constexpr quint32 FILE_VERSION_4 = 0x00040000;
     constexpr quint32 FILE_VERSION_3_1 = 0x00030001;
     constexpr quint32 FILE_VERSION_3 = 0x00030000;
     constexpr quint32 FILE_VERSION_2 = 0x00020000;
     constexpr quint32 FILE_VERSION_MIN = FILE_VERSION_2;
+    constexpr quint32 FILE_VERSION_MAX = FILE_VERSION_4_1;
 
     constexpr quint16 VARIANTMAP_VERSION = 0x0100;
     constexpr quint16 VARIANTMAP_CRITICAL_MASK = 0xFF00;
 
-    const QSysInfo::Endian BYTEORDER = QSysInfo::LittleEndian;
+    constexpr QSysInfo::Endian BYTEORDER = QSysInfo::LittleEndian;
 
     extern const QUuid CIPHER_AES128;
     extern const QUuid CIPHER_AES256;

src/format/KeePass2Reader.cpp

@@ -81,11 +81,8 @@ bool KeePass2Reader::readDatabase(QIODevice* device, QSharedPointer<const Compos
         return false;
     }
 
-    // mask out minor version
-    m_version &= KeePass2::FILE_VERSION_CRITICAL_MASK;
-
-    quint32 maxVersion = KeePass2::FILE_VERSION_4 & KeePass2::FILE_VERSION_CRITICAL_MASK;
-    if (m_version < KeePass2::FILE_VERSION_MIN || m_version > maxVersion) {
+    if (m_version < KeePass2::FILE_VERSION_MIN
+        || (m_version & KeePass2::FILE_VERSION_CRITICAL_MASK) > KeePass2::FILE_VERSION_MAX) {
         raiseError(tr("Unsupported KeePass 2 database version."));
         return false;
     }