Implement sending encrypted files

9 files changed, 113 insertions, 26 deletions

diff --git a/autotests/CMakeLists.txt b/autotests/CMakeLists.txt
index 671d6c08..c11901bf 100644
--- a/autotests/CMakeLists.txt
+++ b/autotests/CMakeLists.txt
@@ -18,4 +18,5 @@ if(${PROJECT_NAME}_ENABLE_E2EE)
     quotient_add_test(NAME testgroupsession)
     quotient_add_test(NAME testolmsession)
     quotient_add_test(NAME testolmutility)
+    quotient_add_test(NAME testfilecrypto)
 endif()
diff --git a/autotests/testfilecrypto.cpp b/autotests/testfilecrypto.cpp
new file mode 100644
index 00000000..e6bec1fe
--- /dev/null
+++ b/autotests/testfilecrypto.cpp
@@ -0,0 +1,17 @@
+// SPDX-FileCopyrightText: 2022 Tobias Fella <fella@posteo.de>
+//
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
+#include "testfilecrypto.h"
+#include "events/encryptedfile.h"
+#include <qtest.h>
+
+using namespace Quotient;
+void TestFileCrypto::encryptDecryptData()
+{
+    QByteArray data = "ABCDEF";
+    auto [file, cipherText] = EncryptedFile::encryptFile(data);
+    auto decrypted = file.decryptFile(cipherText);
+    QCOMPARE(data, decrypted);
+}
+QTEST_APPLESS_MAIN(TestFileCrypto)
diff --git a/autotests/testfilecrypto.h b/autotests/testfilecrypto.h
new file mode 100644
index 00000000..9096a8c7
--- /dev/null
+++ b/autotests/testfilecrypto.h
@@ -0,0 +1,12 @@
+// SPDX-FileCopyrightText: 2022 Tobias Fella <fella@posteo.de>
+//
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
+#include <QtTest/QtTest>
+
+class TestFileCrypto : public QObject
+{
+    Q_OBJECT
+private Q_SLOTS:
+    void encryptDecryptData();
+};
diff --git a/lib/eventitem.cpp b/lib/eventitem.cpp
index a2d65d8d..302ae053 100644
--- a/lib/eventitem.cpp
+++ b/lib/eventitem.cpp
@@ -26,6 +26,16 @@ void PendingEventItem::setFileUploaded(const QUrl& remoteUrl)
     setStatus(EventStatus::FileUploaded);
 }
 
+void PendingEventItem::setEncryptedFile(const EncryptedFile& encryptedFile)
+{
+    if (auto* rme = getAs<RoomMessageEvent>()) {
+        Q_ASSERT(rme->hasFileContent());
+        rme->editContent([encryptedFile](EventContent::TypedBase& ec) {
+            ec.fileInfo()->file = encryptedFile;
+        });
+    }
+}
+
 // Not exactly sure why but this helps with the linker not finding
 // Quotient::EventStatus::staticMetaObject when building Quaternion
 #include "moc_eventitem.cpp"
diff --git a/lib/eventitem.h b/lib/eventitem.h
index f04ef323..d8313736 100644
--- a/lib/eventitem.h
+++ b/lib/eventitem.h
@@ -9,6 +9,8 @@
 #include <any>
 #include <utility>
 
+#include "events/encryptedfile.h"
+
 namespace Quotient {
 
 namespace EventStatus {
@@ -114,6 +116,7 @@ public:
 
     void setDeparted() { setStatus(EventStatus::Departed); }
     void setFileUploaded(const QUrl& remoteUrl);
+    void setEncryptedFile(const EncryptedFile& encryptedFile);
     void setReachedServer(const QString& eventId)
     {
         setStatus(EventStatus::ReachedServer);
diff --git a/lib/events/encryptedfile.cpp b/lib/events/encryptedfile.cpp
index d4a517bd..e90be428 100644
--- a/lib/events/encryptedfile.cpp
+++ b/lib/events/encryptedfile.cpp
@@ -8,6 +8,7 @@
 #ifdef Quotient_E2EE_ENABLED
 #include <openssl/evp.h>
 #include <QtCore/QCryptographicHash>
+#include "e2ee/qolmutils.h"
 #endif
 
 using namespace Quotient;
@@ -27,7 +28,7 @@ QByteArray EncryptedFile::decryptFile(const QByteArray& ciphertext) const
     {
         int length;
         auto* ctx = EVP_CIPHER_CTX_new();
-        QByteArray plaintext(ciphertext.size() + EVP_CIPHER_CTX_block_size(ctx)
+        QByteArray plaintext(ciphertext.size() + EVP_MAX_BLOCK_LENGTH
                                  - 1,
                              '\0');
         EVP_DecryptInit_ex(ctx, EVP_aes_256_ctr(), nullptr,
@@ -44,7 +45,7 @@ QByteArray EncryptedFile::decryptFile(const QByteArray& ciphertext) const
                                 + length,
                             &length);
         EVP_CIPHER_CTX_free(ctx);
-        return plaintext;
+        return plaintext.left(ciphertext.size());
     }
 #else
     qWarning(MAIN) << "This build of libQuotient doesn't support E2EE, "
@@ -53,6 +54,27 @@ QByteArray EncryptedFile::decryptFile(const QByteArray& ciphertext) const
 #endif
 }
 
+std::pair<EncryptedFile, QByteArray> EncryptedFile::encryptFile(const QByteArray &plainText)
+{
+    QByteArray k = getRandom(32);
+    auto kBase64 = k.toBase64();
+    QByteArray iv = getRandom(16);
+    JWK key = {"oct"_ls, {"encrypt"_ls, "decrypt"_ls}, "A256CTR"_ls, QString(k.toBase64()).replace(u'/', u'_').replace(u'+', u'-').left(kBase64.indexOf('=')), true};
+
+    int length;
+    auto* ctx = EVP_CIPHER_CTX_new();
+    QByteArray cipherText(plainText.size(), plainText.size() + EVP_MAX_BLOCK_LENGTH - 1);
+    EVP_EncryptInit_ex(ctx, EVP_aes_256_ctr(), nullptr, reinterpret_cast<const unsigned char*>(k.data()),reinterpret_cast<const unsigned char*>(iv.data()));
+    EVP_EncryptUpdate(ctx, reinterpret_cast<unsigned char*>(cipherText.data()), &length, reinterpret_cast<const unsigned char*>(plainText.data()), plainText.size());
+    EVP_EncryptFinal_ex(ctx, reinterpret_cast<unsigned char*>(cipherText.data()) + length, &length);
+    EVP_CIPHER_CTX_free(ctx);
+
+    auto hash = QCryptographicHash::hash(cipherText, QCryptographicHash::Sha256).toBase64();
+    auto ivBase64 = iv.toBase64();
+    EncryptedFile file = {{}, key, ivBase64.left(ivBase64.indexOf('=')), {{QStringLiteral("sha256"), hash.left(hash.indexOf('='))}}, "v2"_ls};
+    return {file, cipherText};
+}
+
 void JsonObjectConverter<EncryptedFile>::dumpTo(QJsonObject& jo,
                                                 const EncryptedFile& pod)
 {
diff --git a/lib/events/encryptedfile.h b/lib/events/encryptedfile.h
index d0c4a030..2ce35086 100644
--- a/lib/events/encryptedfile.h
+++ b/lib/events/encryptedfile.h
@@ -46,6 +46,7 @@ public:
     QString v;
 
     QByteArray decryptFile(const QByteArray &ciphertext) const;
+    static std::pair<EncryptedFile, QByteArray> encryptFile(const QByteArray &plainText);
 };
 
 template <>
diff --git a/lib/room.cpp b/lib/room.cpp
index 7db9f8e9..763ca31c 100644
--- a/lib/room.cpp
+++ b/lib/room.cpp
@@ -299,8 +299,7 @@ public:
 
     RoomEvent* addAsPending(RoomEventPtr&& event);
 
-    //TODO deleteWhenFinishedis ugly, find out if there's something nicer
-    QString doSendEvent(const RoomEvent* pEvent, bool deleteWhenFinished = false);
+    QString doSendEvent(const RoomEvent* pEvent);
     void onEventSendingFailure(const QString& txnId, BaseJob* call = nullptr);
 
     SetRoomStateWithKeyJob* requestSetState(const QString& evtType,
@@ -2076,6 +2075,16 @@ QString Room::Private::sendEvent(RoomEventPtr&& event)
         qCWarning(MAIN) << q << "has been upgraded, event won't be sent";
         return {};
     }
+
+    return doSendEvent(addAsPending(std::move(event)));
+}
+
+QString Room::Private::doSendEvent(const RoomEvent* pEvent)
+{
+    const auto txnId = pEvent->transactionId();
+    // TODO, #133: Enqueue the job rather than immediately trigger it.
+    const RoomEvent* _event = pEvent;
+
     if (q->usesEncryption()) {
         if (!hasValidMegolmSession() || shouldRotateMegolmSession()) {
             createMegolmSession();
@@ -2083,10 +2092,8 @@ QString Room::Private::sendEvent(RoomEventPtr&& event)
         const auto devicesWithoutKey = getDevicesWithoutKey();
         sendMegolmSession(devicesWithoutKey);
 
-        //TODO check if this is necessary
         //TODO check if we increment the sent message count
-        event->setRoomId(id);
-        const auto encrypted = currentOutboundMegolmSession->encrypt(QJsonDocument(event->fullJson()).toJson());
+        const auto encrypted = currentOutboundMegolmSession->encrypt(QJsonDocument(pEvent->fullJson()).toJson());
         currentOutboundMegolmSession->setMessageCount(currentOutboundMegolmSession->messageCount() + 1);
         connection->saveCurrentOutboundMegolmSession(q, currentOutboundMegolmSession);
         if(std::holds_alternative<QOlmError>(encrypted)) {
@@ -2098,23 +2105,14 @@ QString Room::Private::sendEvent(RoomEventPtr&& event)
         encryptedEvent->setTransactionId(connection->generateTxnId());
         encryptedEvent->setRoomId(id);
         encryptedEvent->setSender(connection->userId());
-        event->setTransactionId(encryptedEvent->transactionId());
         // We show the unencrypted event locally while pending. The echo check will throw the encrypted version out
-        addAsPending(std::move(event));
-        return doSendEvent(encryptedEvent, true);
+        _event = encryptedEvent;
     }
 
-    return doSendEvent(addAsPending(std::move(event)));
-}
-
-QString Room::Private::doSendEvent(const RoomEvent* pEvent, bool deleteWhenFinished)
-{
-    const auto txnId = pEvent->transactionId();
-    // TODO, #133: Enqueue the job rather than immediately trigger it.
     if (auto call =
             connection->callApi<SendMessageJob>(BackgroundRequest, id,
-                                                pEvent->matrixType(), txnId,
-                                                pEvent->contentJson())) {
+                                                _event->matrixType(), txnId,
+                                                _event->contentJson())) {
         Room::connect(call, &BaseJob::sentRequest, q, [this, txnId] {
             auto it = q->findPendingEvent(txnId);
             if (it == unsyncedEvents.end()) {
@@ -2128,7 +2126,7 @@ QString Room::Private::doSendEvent(const RoomEvent* pEvent, bool deleteWhenFinis
         Room::connect(call, &BaseJob::failure, q,
                       std::bind(&Room::Private::onEventSendingFailure, this,
                                 txnId, call));
-        Room::connect(call, &BaseJob::success, q, [this, call, txnId, deleteWhenFinished, pEvent] {
+        Room::connect(call, &BaseJob::success, q, [this, call, txnId, _event] {
             auto it = q->findPendingEvent(txnId);
             if (it != unsyncedEvents.end()) {
                 if (it->deliveryStatus() != EventStatus::ReachedServer) {
@@ -2140,8 +2138,8 @@ QString Room::Private::doSendEvent(const RoomEvent* pEvent, bool deleteWhenFinis
                                << "already merged";
 
             emit q->messageSent(txnId, call->eventId());
-            if (deleteWhenFinished){
-                delete pEvent;
+            if (q->usesEncryption()){
+                delete _event;
             }
         });
     } else
@@ -2266,13 +2264,16 @@ QString Room::Private::doPostFile(RoomEventPtr&& msgEvent, const QUrl& localUrl)
     // Below, the upload job is used as a context object to clean up connections
     const auto& transferJob = fileTransfers.value(txnId).job;
     connect(q, &Room::fileTransferCompleted, transferJob,
-            [this, txnId](const QString& tId, const QUrl&, const QUrl& mxcUri) {
+            [this, txnId](const QString& tId, const QUrl&, const QUrl& mxcUri, Omittable<EncryptedFile> encryptedFile) {
                 if (tId != txnId)
                     return;
 
                 const auto it = q->findPendingEvent(txnId);
                 if (it != unsyncedEvents.end()) {
                     it->setFileUploaded(mxcUri);
+                    if (encryptedFile) {
+                        it->setEncryptedFile(*encryptedFile);
+                    }
                     emit q->pendingEventChanged(
                         int(it - unsyncedEvents.begin()));
                     doSendEvent(it->get());
@@ -2508,6 +2509,20 @@ void Room::uploadFile(const QString& id, const QUrl& localFilename,
     Q_ASSERT_X(localFilename.isLocalFile(), __FUNCTION__,
                "localFilename should point at a local file");
     auto fileName = localFilename.toLocalFile();
+    Omittable<EncryptedFile> encryptedFile = std::nullopt;
+#ifdef Quotient_E2EE_ENABLED
+    QTemporaryFile tempFile;
+    if (usesEncryption()) {
+        tempFile.open();
+        QFile file(localFilename.toLocalFile());
+        file.open(QFile::ReadOnly);
+        auto [e, data] = EncryptedFile::encryptFile(file.readAll());
+        tempFile.write(data);
+        tempFile.close();
+        fileName = QFileInfo(tempFile).absoluteFilePath();
+        encryptedFile = e;
+    }
+#endif
     auto job = connection()->uploadFile(fileName, overrideContentType);
     if (isJobPending(job)) {
         d->fileTransfers[id] = { job, fileName, true };
@@ -2516,9 +2531,15 @@ void Room::uploadFile(const QString& id, const QUrl& localFilename,
                     d->fileTransfers[id].update(sent, total);
                     emit fileTransferProgress(id, sent, total);
                 });
-        connect(job, &BaseJob::success, this, [this, id, localFilename, job] {
+        connect(job, &BaseJob::success, this, [this, id, localFilename, job, encryptedFile] {
             d->fileTransfers[id].status = FileTransferInfo::Completed;
-            emit fileTransferCompleted(id, localFilename, QUrl(job->contentUri()));
+            if (encryptedFile) {
+                auto file = *encryptedFile;
+                file.url = QUrl(job->contentUri());
+                emit fileTransferCompleted(id, localFilename, QUrl(job->contentUri()), file);
+            } else {
+                emit fileTransferCompleted(id, localFilename, QUrl(job->contentUri()));
+            }
         });
         connect(job, &BaseJob::failure, this,
                 std::bind(&Private::failedTransfer, d, id, job->errorString()));
diff --git a/lib/room.h b/lib/room.h
index 6e6071f0..d5a8366a 100644
--- a/lib/room.h
+++ b/lib/room.h
@@ -999,7 +999,7 @@ Q_SIGNALS:
 
     void newFileTransfer(QString id, QUrl localFile);
     void fileTransferProgress(QString id, qint64 progress, qint64 total);
-    void fileTransferCompleted(QString id, QUrl localFile, QUrl mxcUrl);
+    void fileTransferCompleted(QString id, QUrl localFile, QUrl mxcUrl, Omittable<EncryptedFile> encryptedFile = std::nullopt);
     void fileTransferFailed(QString id, QString errorMessage = {});
     // fileTransferCancelled() is no more here; use fileTransferFailed() and
     // check the transfer status instead