Implement XEP-0384: OMEMO Encryption v0.8

This implements XEP-0384 in version v0.8 with a manager and storage
classes to be user-implemented for persistant storage.

The license of the code is LGPL-2.1-or-later as usual.  However since
libomemo-c (libsignal-protocol-c) is GPL-3.0, the built binary is always
licensed under GPL-3.0.  Having our code LGPL licensed will make it
avoids relicensing in the future in case we port it to an LGPL
compatible omemo library.

Closes #133.

Co-authored-by: Linus Jahn <lnj@kaidan.im>

1 files changed, 157 insertions, 0 deletions

diff --git a/src/client/QXmppOmemoManager.h b/src/client/QXmppOmemoManager.h
new file mode 100644
index 00000000..91d57799
--- /dev/null
+++ b/src/client/QXmppOmemoManager.h
@@ -0,0 +1,157 @@
+// SPDX-FileCopyrightText: 2022 Melvin Keskin <melvo@olomono.de>
+//
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
+#ifndef QXMPPOMEMOMANAGER_H
+#define QXMPPOMEMOMANAGER_H
+
+#include "QXmppClientExtension.h"
+#include "QXmppE2eeExtension.h"
+#include "QXmppMessageHandler.h"
+#include "QXmppPubSubEventHandler.h"
+#include "QXmppPubSubManager.h"
+#include "QXmppTrustSecurityPolicy.h"
+
+class QXmppOmemoDevicePrivate;
+class QXmppOmemoManagerPrivate;
+class QXmppOmemoOwnDevicePrivate;
+class QXmppOmemoStorage;
+
+class QXMPP_EXPORT QXmppOmemoOwnDevice
+{
+public:
+    QXmppOmemoOwnDevice();
+    QXmppOmemoOwnDevice(const QXmppOmemoOwnDevice &other);
+    QXmppOmemoOwnDevice(QXmppOmemoOwnDevice &&) noexcept;
+    ~QXmppOmemoOwnDevice();
+
+    QXmppOmemoOwnDevice &operator=(const QXmppOmemoOwnDevice &);
+    QXmppOmemoOwnDevice &operator=(QXmppOmemoOwnDevice &&);
+
+    QString label() const;
+    void setLabel(const QString &label);
+
+    QByteArray keyId() const;
+    void setKeyId(const QByteArray &keyId);
+
+private:
+    QSharedDataPointer<QXmppOmemoOwnDevicePrivate> d;
+};
+
+class QXMPP_EXPORT QXmppOmemoDevice
+{
+public:
+    QXmppOmemoDevice();
+    QXmppOmemoDevice(const QXmppOmemoDevice &other);
+    QXmppOmemoDevice(QXmppOmemoDevice &&) noexcept;
+    ~QXmppOmemoDevice();
+
+    QXmppOmemoDevice &operator=(const QXmppOmemoDevice &);
+    QXmppOmemoDevice &operator=(QXmppOmemoDevice &&);
+
+    QString jid() const;
+    void setJid(const QString &jid);
+
+    QString label() const;
+    void setLabel(const QString &label);
+
+    QByteArray keyId() const;
+    void setKeyId(const QByteArray &keyId);
+
+    QXmpp::TrustLevel trustLevel() const;
+    void setTrustLevel(QXmpp::TrustLevel trustLevel);
+
+private:
+    QSharedDataPointer<QXmppOmemoDevicePrivate> d;
+};
+
+class QXMPP_EXPORT QXmppOmemoManager : public QXmppClientExtension, public QXmppE2eeExtension, public QXmppPubSubEventHandler, public QXmppMessageHandler
+{
+    Q_OBJECT
+
+public:
+    using Result = std::variant<QXmpp::Success, QXmppStanza::Error>;
+
+    struct DevicesResult
+    {
+        QString jid;
+        Result result;
+    };
+
+    explicit QXmppOmemoManager(QXmppOmemoStorage *omemoStorage);
+    ~QXmppOmemoManager() override;
+
+    QFuture<bool> load();
+    QFuture<bool> setUp();
+
+    QFuture<QByteArray> ownKey();
+    QFuture<QHash<QXmpp::TrustLevel, QMultiHash<QString, QByteArray>>> keys(QXmpp::TrustLevels trustLevels = {});
+    QFuture<QHash<QString, QHash<QByteArray, QXmpp::TrustLevel>>> keys(const QList<QString> &jids, QXmpp::TrustLevels trustLevels = {});
+
+    QFuture<bool> changeDeviceLabel(const QString &deviceLabel = {});
+
+    int maximumDevicesPerJid() const;
+    void setMaximumDevicesPerJid(int maximum);
+
+    int maximumDevicesPerStanza() const;
+    void setMaximumDevicesPerStanza(int maximum);
+
+    QFuture<DevicesResult> requestDeviceLists(const QList<QString> &jids);
+    QFuture<DevicesResult> subscribeToDeviceLists(const QList<QString> &jids);
+    QFuture<DevicesResult> unsubscribeFromDeviceLists();
+
+    QXmppOmemoOwnDevice ownDevice();
+    QFuture<QVector<QXmppOmemoDevice>> devices();
+    QFuture<QVector<QXmppOmemoDevice>> devices(const QList<QString> &jids);
+    QFuture<QXmppPubSubManager::Result> removeContactDevices(const QString &jid);
+
+    void setAcceptedSessionBuildingTrustLevels(QXmpp::TrustLevels trustLevels);
+    QXmpp::TrustLevels acceptedSessionBuildingTrustLevels();
+
+    void setNewDeviceAutoSessionBuildingEnabled(bool isNewDeviceAutoSessionBuildingEnabled);
+    bool isNewDeviceAutoSessionBuildingEnabled();
+
+    QFuture<void> buildMissingSessions(const QList<QString> &jids);
+
+    QFuture<bool> resetOwnDevice();
+    QFuture<bool> resetAll();
+
+    QFuture<void> setSecurityPolicy(QXmpp::TrustSecurityPolicy securityPolicy);
+    QFuture<QXmpp::TrustSecurityPolicy> securityPolicy();
+
+    QFuture<void> setTrustLevel(const QMultiHash<QString, QByteArray> &keyIds, QXmpp::TrustLevel trustLevel);
+    QFuture<QXmpp::TrustLevel> trustLevel(const QString &keyOwnerJid, const QByteArray &keyId);
+
+    /// \cond
+    QFuture<MessageEncryptResult> encryptMessage(QXmppMessage &&message, const std::optional<QXmppSendStanzaParams> &params) override;
+
+    QFuture<IqEncryptResult> encryptIq(QXmppIq &&iq, const std::optional<QXmppSendStanzaParams> &params) override;
+    QFuture<IqDecryptResult> decryptIq(const QDomElement &element) override;
+
+    QStringList discoveryFeatures() const override;
+    bool handleStanza(const QDomElement &stanza) override;
+    bool handleMessage(const QXmppMessage &message) override;
+    /// \endcond
+
+    Q_SIGNAL void trustLevelsChanged(const QMultiHash<QString, QByteArray> &modifiedKeys);
+
+    Q_SIGNAL void deviceAdded(const QString &jid, uint32_t deviceId);
+    Q_SIGNAL void deviceChanged(const QString &jid, uint32_t deviceId);
+    Q_SIGNAL void deviceRemoved(const QString &jid, uint32_t deviceId);
+    Q_SIGNAL void devicesRemoved(const QString &jid);
+    Q_SIGNAL void allDevicesRemoved();
+
+protected:
+    /// \cond
+    void setClient(QXmppClient *client) override;
+    bool handlePubSubEvent(const QDomElement &element, const QString &pubSubService, const QString &nodeName) override;
+    /// \endcond
+
+private:
+    std::unique_ptr<QXmppOmemoManagerPrivate> d;
+
+    friend class QXmppOmemoManagerPrivate;
+    friend class tst_QXmppOmemoManager;
+};
+
+#endif  // QXMPPOMEMOMANAGER_H