rkvm

rkvm shares a keyboard and mouse between computers by forwarding raw Linux input events over an encrypted connection. The Linux server captures the physical input devices, and each configured shortcut cycles control between the server and connected clients.

This fork adds an experimental native Windows client that runs as a Windows service and supports the normal desktop, UAC secure desktop, and the Windows lock/sign-in desktop.

Features

• TLS encryption using rustls
• Linux server and Linux client
• Native Windows client service
• UAC and lock-screen input support on Windows
• Display-server independent: X11, Wayland, and a graphical session are not required
• Raw key forwarding without keyboard-layout translation
• Configurable multi-key switching shortcut

Compatibility

The Windows client in this fork uses protocol version 6. The server and client must come from the same release of this fork. The stock RKVM 0.6.1 package uses protocol version 5 and is not compatible.

Documentation

• Windows installation, configuration, and troubleshooting
• Declarative NixOS server setup
• Supported switching keys

Linux requirements

• The uinput kernel module. Confirm that /dev/uinput exists.
• libevdev development files (sudo apt install libevdev-dev on Debian/Ubuntu)
• Clang/LLVM (sudo apt install clang on Debian/Ubuntu)

Build from source

cargo build --release
sudo install -Dm755 target/release/rkvm-server /usr/local/bin/rkvm-server
sudo install -Dm755 target/release/rkvm-client /usr/local/bin/rkvm-client
sudo install -Dm755 target/release/rkvm-certificate-gen \
  /usr/local/bin/rkvm-certificate-gen

For Windows, download the ZIP attached to the latest GitHub release instead of building manually.

Basic server setup

Generate a certificate and private key:

sudo install -d -m 0755 /etc/rkvm
sudo rkvm-certificate-gen \
  /etc/rkvm/certificate.pem \
  /etc/rkvm/key.pem \
  --dns-name "$(hostname)" \
  --ip-address 192.0.2.10
sudo chmod 0644 /etc/rkvm/certificate.pem
sudo chmod 0600 /etc/rkvm/key.pem

Replace 192.0.2.10 with the server address used by clients. Copy example/server.toml to /etc/rkvm/server.toml, then change the password and switching shortcut.

Test the server before enabling it permanently:

sudo rkvm-server /etc/rkvm/server.toml --shutdown-after 15

The example service files are in systemd.

Security boundaries

The Windows service runs as LocalSystem because input on UAC and Winlogon desktops requires elevated desktop access. Its local named pipe is restricted to LocalSystem and administrators.

Windows deliberately prevents applications from synthesizing Ctrl+Alt+Delete. Keep a physical input device available for the secure-attention sequence and during initial testing.

Project structure

• rkvm-server - captures Linux input and forwards it to clients
• rkvm-client - Linux client and Windows service/client processes
• rkvm-input - Linux input handling and Windows input injection
• rkvm-net - protocol encoding, authentication, and TLS
• rkvm-certificate-gen - certificate generation utility
• windows-service - Windows installer and uninstaller

Origin and license

This project is based on htrefil/rkvm and includes work derived from the experimental Windows client by Unknow0/rkvm.

Contributions are welcome. If you find RKVM useful, you can support the original author through Ko-fi.

Licensed under the MIT License.