Add file encryption functions and Encryption/DecryptionDevice

The devices allow it to encrypt or decrypt data on the fly when reading
or writing data.

1 files changed, 74 insertions, 0 deletions

diff --git a/src/client/QXmppFileEncryption.h b/src/client/QXmppFileEncryption.h
new file mode 100644
index 00000000..b1108b22
--- /dev/null
+++ b/src/client/QXmppFileEncryption.h
@@ -0,0 +1,74 @@
+// SPDX-FileCopyrightText: 2022 Linus Jahn <lnj@kaidan.im>
+//
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
+#ifndef QXMPPFILEENCRYPTION_H
+#define QXMPPFILEENCRYPTION_H
+
+#include "QXmppGlobal.h"
+
+#include <memory>
+
+#include <QIODevice>
+
+namespace QCA {
+class Cipher;
+class Initializer;
+}  // namespace QCA
+
+namespace QXmpp::Private::Encryption {
+
+enum Direction {
+    Encode,
+    Decode,
+};
+
+QByteArray process(const QByteArray &data, Cipher cipherConfig, Direction direction, const QByteArray &key, const QByteArray &iv);
+QByteArray generateKey(Cipher cipher);
+QByteArray generateInitializationVector(Cipher);
+
+// export for tests
+class QXMPP_EXPORT EncryptionDevice : public QIODevice
+{
+public:
+    EncryptionDevice(std::unique_ptr<QIODevice> input, Cipher config, const QByteArray &key, const QByteArray &iv);
+    ~EncryptionDevice() override;
+
+    bool open(QIODevice::OpenMode mode) override;
+    void close() override;
+    bool isSequential() const override;
+    qint64 size() const override;
+    qint64 readData(char *data, qint64 maxlen) override;
+    qint64 writeData(const char *data, qint64 len) override;
+
+private:
+    Cipher m_cipherConfig;
+    bool m_finalized = false;
+    std::vector<char> m_outputBuffer;
+    std::unique_ptr<QIODevice> m_input;
+    std::unique_ptr<QCA::Cipher> m_cipher;
+};
+
+class DecryptionDevice : public QIODevice
+{
+public:
+    DecryptionDevice(std::unique_ptr<QIODevice> output, Cipher config, const QByteArray &key, const QByteArray &iv);
+    ~DecryptionDevice() override;
+
+    bool open(QIODevice::OpenMode mode) override;
+    void close() override;
+    bool isSequential() const override;
+    qint64 size() const override;
+    qint64 readData(char *data, qint64 maxlen) override;
+    qint64 writeData(const char *data, qint64 len) override;
+
+private:
+    Cipher m_cipherConfig;
+    std::vector<char> m_outputBuffer;
+    std::unique_ptr<QIODevice> m_output;
+    std::unique_ptr<QCA::Cipher> m_cipher;
+};
+
+}  // namespace QXmpp::Private::Encryption
+
+#endif  // QXMPPFILEENCRYPTION_H