feat(e2ee): add basic support for e2ee metadata format 2.1

add ability to use encrypted root folder with 2.1 metadata format

this is lacking ability to create public encrypted share link

Signed-off-by: Matthieu Gallien <matthieu.gallien@nextcloud.com>

Author: mgallien

src/libsync/foldermetadata.cpp

@@ -409,6 +409,8 @@ void FolderMetadata::setupVersionFromExistingMetadata(const QByteArray &metadata
         _existingMetadataVersion = MetadataVersion::Version1_2;
     } else if (versionStringFromMetadata == QStringLiteral("2.0") || versionStringFromMetadata == QStringLiteral("2")) {
         _existingMetadataVersion = MetadataVersion::Version2_0;
+    } else if (versionStringFromMetadata == QStringLiteral("2.1")) {
+        _existingMetadataVersion = MetadataVersion::Version2_1;
     } else if (versionStringFromMetadata == QStringLiteral("1.0")
         || versionStringFromMetadata == QStringLiteral("1.1")) {
         // We used to have an intermediate 1.1 after applying a security-vulnerability fix for metadata keys.
@@ -838,6 +840,7 @@ quint64 FolderMetadata::newCounter() const
 EncryptionStatusEnums::ItemEncryptionStatus FolderMetadata::fromMedataVersionToItemEncryptionStatus(const MetadataVersion metadataVersion)
 {
     switch (metadataVersion) {
+    case FolderMetadata::MetadataVersion::Version2_1:
     case FolderMetadata::MetadataVersion::Version2_0:
         return SyncFileItem::EncryptionStatus::EncryptedMigratedV2_0;
     case FolderMetadata::MetadataVersion::Version1_2:

src/libsync/foldermetadata.h

@@ -36,14 +36,6 @@ class OWNCLOUDSYNC_EXPORT FolderMetadata : public QObject
         QByteArray encryptedMetadataKey;
     };
 
-    // based on api-version and "version" key in metadata JSON
-    enum MetadataVersion {
-        VersionUndefined = -1,
-        Version1,
-        Version1_2,
-        Version2_0,
-    };
-
     struct UserWithFileDropEntryAccess {
         QString userId;
         QByteArray decryptedFiledropKey;
@@ -90,6 +82,16 @@ class OWNCLOUDSYNC_EXPORT FolderMetadata : public QObject
     };
     Q_ENUM(CertificateType)
 
+    // based on api-version and "version" key in metadata JSON
+    enum class MetadataVersion {
+        VersionUndefined = -1,
+        Version1,
+        Version1_2,
+        Version2_0,
+        Version2_1,
+    };
+    Q_ENUM(MetadataVersion)
+
     FolderMetadata(AccountPtr account, const QString &remoteFolderRoot, FolderType folderType = FolderType::Nested);
     /*
     * construct metadata based on RootEncryptedFolderInfo