fix(UI): validate E2EE file names

src/libsync/foldermetadata.cpp

@@ -1,3 +1,3 @@
 /*
  * SPDX-FileCopyrightText: 2023 Nextcloud GmbH and Nextcloud contributors
  * SPDX-License-Identifier: GPL-2.0-or-later
@@ -9,6 +9,7 @@
 #include "clientsideencryption.h"
 #include "clientsideencryptionjobs.h"
 #include <common/checksums.h>
+#include <QDir>
 #include <QJsonArray>
 #include <QJsonDocument>
 #include <QSslCertificate>
@@ -49,6 +50,27 @@
 }
 }
 
+bool FolderMetadata::isOriginalFilenameValid(const QString &originalFilename)
+{
+    if (originalFilename.isEmpty()) {
+        return false;
+    }
+
+    if (originalFilename == QStringLiteral(".")
+        || originalFilename == QStringLiteral("..")) {
+        return false;
+    }
+
+    if (originalFilename.contains(QLatin1Char('/'))
+        || originalFilename.contains(QLatin1Char('\\'))
+        || originalFilename.contains(QChar(0))) {
+        return false;
+    }
+
+    const auto slashPrefixedName = QStringLiteral("/") + originalFilename;
+    return QDir::cleanPath(slashPrefixedName) == slashPrefixedName;
+}
+
 bool FolderMetadata::EncryptedFile::isDirectory() const
 {
     return mimetype.isEmpty() || mimetype == QByteArrayLiteral("inode/directory") || mimetype == QByteArrayLiteral("httpd/unix-directory");
@@ -121,6 +143,11 @@
         _account->reportClientStatus(OCC::ClientStatusReportingStatus::E2EeError_GeneralError);
         return;
     }
+    if (_existingMetadataVersion < MetadataVersion::Version2_0 && !_initialSignature.isEmpty()) {
+        qCWarning(lcCseMetadata()) << "Could not setup legacy metadata with a V2 signature.";
+        _account->reportClientStatus(OCC::ClientStatusReportingStatus::E2EeError_GeneralError);
+        return;
+    }
     if (_existingMetadataVersion < MetadataVersion::Version2_0) {
         setupExistingMetadataLegacy(metadata);
         return;
@@ -250,22 +277,39 @@
         _counter = counterVariantFromJson.value<quint64>();
     }
 
+    QVector<EncryptedFile> parsedFiles;
+    parsedFiles.reserve(files.size() + folders.size());
+
     for (auto it = files.constBegin(), end = files.constEnd(); it != end; ++it) {
         const auto parsedEncryptedFile = parseEncryptedFileFromJson(it.key(), it.value());
-        if (!parsedEncryptedFile.originalFilename.isEmpty()) {
-            _files.push_back(parsedEncryptedFile);
+        if (parsedEncryptedFile.originalFilename.isEmpty()) {
+            qCWarning(lcCseMetadata()) << "Could not setup metadata. Encrypted file" << it.key() << "metadata is invalid.";
+            _account->reportClientStatus(OCC::ClientStatusReportingStatus::E2EeError_GeneralError);
+            return;
         }
+        parsedFiles.push_back(parsedEncryptedFile);
     }
 
     for (auto it = folders.constBegin(); it != folders.constEnd(); ++it) {
         const auto folderName = it.value().toString();
-        if (!folderName.isEmpty()) {
-            EncryptedFile file;
-            file.encryptedFilename = it.key();
-            file.originalFilename = folderName;
-            _files.push_back(file);
+        if (folderName.isEmpty()) {
+            qCWarning(lcCseMetadata()) << "Could not setup metadata. Encrypted folder" << it.key() << "metadata has an empty file name.";
+            _account->reportClientStatus(OCC::ClientStatusReportingStatus::E2EeError_GeneralError);
+            return;
         }
+
+        if (!isOriginalFilenameValid(folderName)) {
+            qCWarning(lcCseMetadata()) << "Could not setup metadata. Encrypted folder" << it.key() << "metadata has an invalid file name.";
+            _account->reportClientStatus(OCC::ClientStatusReportingStatus::E2EeError_GeneralError);
+            return;
+        }
+
+        EncryptedFile file;
+        file.encryptedFilename = it.key();
+        file.originalFilename = folderName;
+        parsedFiles.push_back(file);
     }
+    _files = parsedFiles;
     _isMetadataValid = true;
 }
 
@@ -349,12 +393,20 @@
 
         const auto decryptedFileObj = decryptedFileDoc.object();
 
-        if (decryptedFileObj["filename"].toString().isEmpty()) {
-            qCWarning(lcCseMetadata) << "decrypted metadata" << decryptedFileDoc.toJson(QJsonDocument::Compact) << "skipping encrypted file" << file.encryptedFilename << "metadata has an empty file name";
-            continue;
+        const auto originalFilename = decryptedFileObj["filename"].toString();
+        if (originalFilename.isEmpty()) {
+            qCWarning(lcCseMetadata) << "decrypted metadata" << decryptedFileDoc.toJson(QJsonDocument::Compact) << "Could not setup legacy metadata. Encrypted file" << file.encryptedFilename << "metadata has an empty file name.";
+            _account->reportClientStatus(OCC::ClientStatusReportingStatus::E2EeError_GeneralError);
+            return;
+        }
+
+        if (!isOriginalFilenameValid(originalFilename)) {
+            qCWarning(lcCseMetadata) << "Could not setup legacy metadata. Encrypted file" << file.encryptedFilename << "metadata has an invalid file name.";
+            _account->reportClientStatus(OCC::ClientStatusReportingStatus::E2EeError_GeneralError);
+            return;
         }
 
-        file.originalFilename = decryptedFileObj["filename"].toString();
+        file.originalFilename = originalFilename;
         file.encryptionKey = QByteArray::fromBase64(decryptedFileObj["key"].toString().toLocal8Bit());
         file.mimetype = decryptedFileObj["mimetype"].toString().toLocal8Bit();
 
@@ -508,10 +560,17 @@
 FolderMetadata::EncryptedFile FolderMetadata::parseEncryptedFileFromJson(const QString &encryptedFilename, const QJsonValue &fileJSON) const
 {
     const auto fileObj = fileJSON.toObject();
-    if (fileObj["filename"].toString().isEmpty()) {
+    const auto originalFilename = fileObj["filename"].toString();
+    if (originalFilename.isEmpty()) {
         qCWarning(lcCseMetadata()) << "skipping encrypted file" << encryptedFilename << "metadata has an empty file name";
         return {};
     }
+
+    if (!isOriginalFilenameValid(originalFilename)) {
+        qCWarning(lcCseMetadata()) << "skipping encrypted file" << encryptedFilename << "metadata has an invalid file name";
+        _account->reportClientStatus(OCC::ClientStatusReportingStatus::E2EeError_GeneralError);
+        return {};
+    }
 
     EncryptedFile file;
     file.encryptedFilename = encryptedFilename;
@@ -521,7 +580,7 @@
         nonce = QByteArray::fromBase64(fileObj[nonceKey].toString().toLocal8Bit());
     }
     file.initializationVector = nonce;
-    file.originalFilename = fileObj["filename"].toString();
+    file.originalFilename = originalFilename;
     file.encryptionKey = QByteArray::fromBase64(fileObj["key"].toString().toLocal8Bit());
     file.mimetype = fileObj["mimetype"].toString().toLocal8Bit();
 
@@ -535,6 +594,11 @@
 
 QJsonObject FolderMetadata::convertFileToJsonObject(const EncryptedFile *encryptedFile) const
 {
+    if (!encryptedFile || !isOriginalFilenameValid(encryptedFile->originalFilename)) {
+        qCWarning(lcCseMetadata()) << "Metadata generation failed. Invalid original file name.";
+        return {};
+    }
+
     QJsonObject file;
     file.insert("key", QString(encryptedFile->encryptionKey.toBase64()));
     file.insert("filename", encryptedFile->originalFilename);
@@ -728,6 +792,12 @@
 
     QJsonObject files;
     for (auto it = _files.constBegin(), end = _files.constEnd(); it != end; ++it) {
+        if (!isOriginalFilenameValid(it->originalFilename)) {
+            qCWarning(lcCseMetadata) << "Metadata generation failed. Invalid original file name for encrypted file" << it->encryptedFilename;
+            _account->reportClientStatus(OCC::ClientStatusReportingStatus::E2EeError_GeneralError);
+            return {};
+        }
+
         QJsonObject encrypted;
         encrypted.insert("key", QString(it->encryptionKey.toBase64()));
         encrypted.insert("filename", it->originalFilename);
@@ -919,11 +989,17 @@
     return metdataModified.toJson(QJsonDocument::Compact);
 }
 
-void FolderMetadata::addEncryptedFile(const EncryptedFile &f) {
+bool FolderMetadata::addEncryptedFile(const EncryptedFile &f) {
     Q_ASSERT(_isMetadataValid);
     if (!_isMetadataValid) {
         qCWarning(lcCseMetadata()) << "Could not add encrypted file to non-initialized metadata!";
-        return;
+        return false;
+    }
+
+    if (!isOriginalFilenameValid(f.originalFilename)) {
+        qCWarning(lcCseMetadata()) << "Could not add encrypted file with invalid original file name.";
+        _account->reportClientStatus(OCC::ClientStatusReportingStatus::E2EeError_GeneralError);
+        return false;
     }
 
     for (int i = 0; i < _files.size(); ++i) {
@@ -934,6 +1010,7 @@
     }
 
     _files.append(f);
+    return true;
 }
 
 const QByteArray FolderMetadata::binaryMetadataKeyForDecryption() const
@@ -1006,7 +1083,9 @@
             _account->reportClientStatus(OCC::ClientStatusReportingStatus::E2EeError_GeneralError);
             return false;
         }
-        addEncryptedFile(parsedEncryptedFile);
+        if (!addEncryptedFile(parsedEncryptedFile)) {
+            return false;
+        }
     }
 
     _fileDropEntries.clear();

src/libsync/foldermetadata.h

@@ -147,7 +147,7 @@ class OWNCLOUDSYNC_EXPORT FolderMetadata : public QObject
     static MetadataVersion setupVersionFromExistingMetadata(const QByteArray &metadata);
 
 public slots:
-    void addEncryptedFile(const OCC::FolderMetadata::EncryptedFile &f);
+    [[nodiscard]] bool addEncryptedFile(const OCC::FolderMetadata::EncryptedFile &f);
     void removeEncryptedFile(const OCC::FolderMetadata::EncryptedFile &f);
     void removeAllEncryptedFiles();
 
@@ -172,6 +172,8 @@ public slots:
 
     [[nodiscard]] QJsonObject convertFileToJsonObject(const EncryptedFile *encryptedFile) const;
 
+    [[nodiscard]] static bool isOriginalFilenameValid(const QString &originalFilename);
+
     [[nodiscard]] MetadataVersion latestSupportedMetadataVersion() const;
 
     [[nodiscard]] bool parseFileDropPart(const QJsonDocument &doc);

src/libsync/propagateremotemkdir.cpp

@@ -1,3 +1,3 @@
 /*
  * SPDX-FileCopyrightText: 2018 Nextcloud GmbH and Nextcloud contributors
  * SPDX-FileCopyrightText: 2014 ownCloud GmbH
@@ -210,7 +210,11 @@
     connect(_uploadEncryptedHelper, &PropagateUploadEncrypted::finalized,
       this, &PropagateRemoteMkdir::slotStartEncryptedMkcolJob);
     connect(_uploadEncryptedHelper, &PropagateUploadEncrypted::error,
-      []{ qCWarning(lcPropagateRemoteMkdir) << "Error setting up encryption."; });
+      this, [this] {
+          qCWarning(lcPropagateRemoteMkdir) << "Error setting up encryption.";
+          propagator()->_activeJobList.removeOne(this);
+          done(SyncFileItem::FatalError, tr("Failed to create encrypted folder."), ErrorCategory::GenericError);
+      });
     _uploadEncryptedHelper->start();
 }
 

src/libsync/propagateuploadencrypted.cpp

@@ -163,7 +163,11 @@ void PropagateUploadEncrypted::slotFetchMetadataJobFinished(int statusCode, cons
 
     qCDebug(lcPropagateUploadEncrypted) << "Creating the metadata for the encrypted file.";
 
-    metadata->addEncryptedFile(encryptedFile);
+    if (!metadata->addEncryptedFile(encryptedFile)) {
+        qCWarning(lcPropagateUploadEncrypted()) << "There was an error encrypting the file, aborting upload. Invalid metadata file name.";
+        emit error();
+        return;
+    }
 
     qCDebug(lcPropagateUploadEncrypted) << "Metadata created, sending to the server.";