wayvnc

Introduction

This is a VNC server for wlroots-based Wayland compositors (:no_entry: Gnome, KDE and Weston are not supported). It attaches to a running Wayland session, creates virtual input devices, and exposes a single display via the RFB protocol. The Wayland session may be a headless one, so it is also possible to run wayvnc without a physical display attached.

Please check the FAQ for answers to common questions. For further support, join the #wayvnc IRC channel on libera.chat, or ask your questions on the GitHub discussion forum for the project.

Building

Runtime Dependencies

• aml
• drm
• gbm (optional)
• libxkbcommon
• neatvnc
• pam (optional)
• pixman
• jansson

Build Dependencies

• GCC
• meson
• ninja
• pkg-config

For Arch Linux

pacman -S base-devel libglvnd libxkbcommon pixman gnutls jansson

For Fedora 37

dnf install -y meson gcc ninja-build pkg-config egl-wayland egl-wayland-devel \
	mesa-libEGL-devel mesa-libEGL libwayland-egl libglvnd-devel \
	libglvnd-core-devel libglvnd mesa-libGLES-devel mesa-libGLES \
	libxkbcommon-devel libxkbcommon libwayland-client \
	pam-devel pixman-devel libgbm-devel libdrm-devel scdoc \
	libavcodec-free-devel libavfilter-free-devel libavutil-free-devel \
	turbojpeg-devel	wayland-devel gnutls-devel jansson-devel

For Debian (unstable / testing)

apt build-dep wayvnc

For Ubuntu

apt install meson libdrm-dev libxkbcommon-dev libwlroots-dev libjansson-dev \
	libpam0g-dev libgnutls28-dev libavfilter-dev libavcodec-dev \
	libavutil-dev libturbojpeg0-dev scdoc

Additional build-time dependencies

The easiest way to satisfy the neatvnc and aml dependencies is to link to them in the subprojects directory:

git clone https://github.com/any1/wayvnc.git
git clone https://github.com/any1/neatvnc.git
git clone https://github.com/any1/aml.git

mkdir wayvnc/subprojects
cd wayvnc/subprojects
ln -s ../../neatvnc .
ln -s ../../aml .
cd -

mkdir neatvnc/subprojects
cd neatvnc/subprojects
ln -s ../../aml .
cd -

Configure and Build

meson build
ninja -C build

To run the unit tests:

meson test -C build

To run the integration tests:

./test/integration/integration.sh

Running

Wayvnc can be run from the build directory like so:

./build/wayvnc

:radioactive: The server only accepts connections from localhost by default. To accept connections via any interface, set the address to 0.0.0.0 like this:

./build/wayvnc 0.0.0.0

:warning: Do not do this on a public network or the internet without user authentication enabled. The best way to protect your VNC connection is to use SSH tunneling while listening on localhost, but users can also be authenticated when connecting to wayvnc.

Encryption & Authentication

VeNCrypt (TLS)

For TLS, you'll need a private X509 key and a certificate. A self-signed key with a certificate can be generated like so:

cd ~/.config/wayvnc
openssl req -x509 -newkey ec -pkeyopt ec_paramgen_curve:secp384r1 -sha384 \
	-days 3650 -nodes -keyout tls_key.pem -out tls_cert.pem \
	-subj /CN=localhost \
	-addext subjectAltName=DNS:localhost,DNS:localhost,IP:127.0.0.1
cd -

Replace localhost and 127.0.0.1 in the command above with your public facing host name and IP address, respectively, or just keep them as is if you're testing locally.

Create a config with the authentication info and load it using the --config command line option or place it at the default location $HOME/.config/wayvnc/config.

use_relative_paths=true
address=0.0.0.0
enable_auth=true
username=luser
password=p455w0rd
private_key_file=tls_key.pem
certificate_file=tls_cert.pem

RSA-AES

The RSA-AES security type combines RSA with AES in EAX mode to provide secure authentication and encryption that's resilient to eavesdropping and MITM. Its main weakness is that the user has to verify the server's credentials on first use. Thereafter, the client software should warn the user if the server's credentials change. It's a Trust on First Use (TOFU) scheme as employed by SSH.

For the RSA-AES to be enabled, you need to generate an RSA key. This can be achieved like so:

ssh-keygen -m pem -f ~/.config/wayvnc/rsa_key.pem -t rsa -N ""

You also need to tell wayvnc where this file is located, by setting setting the rsa_private_key_file configuration parameter:

use_relative_paths=true
address=0.0.0.0
enable_auth=true
username=luser
password=p455w0rd
rsa_private_key_file=rsa_key.pem

You may also add credentials for TLS in combination with RSA. The client will choose.

DES Authentication (Legacy)

:warning: DES authentication provides no encryption of the VNC session. It uses an outdated challenge-response scheme where only the first 8 characters of the password are used. This is not secure by any modern standard.

This option exists solely for compatibility with VNC clients that support DES but do not support the absence of authentication, such as macOS Screen Sharing.

If you need to support such clients, add the following to your config:

enable_auth=true
password=p455w0rd
relax_encryption=true
allow_broken_crypto=true

DES authentication does not work when enable_pam is enabled, as PAM overrides password-based authentication.

On a network you do not fully trust, use SSH tunneling or a VPN to provide encryption.

wayvncctl control socket

To facilitate runtime interaction and control, wayvnc opens a unix domain socket at $XDG_RUNTIME_DIR/wayvncctl (or a fallback of /tmp/wayvncctl-$UID). A client can connect and exchange json-formatted IPC messages to query and control the running wayvnc instance.

Use the wayvncctl utility to interact with this control socket from the command line.

See the wayvnc(1) manpage for an in-depth description of the IPC protocol and the available commands, and wayvncctl(1) for more on the command line interface.

There is also a handy event-loop mode that can be used to run commands when various events occur in wayvnc. See examples/event-watcher for more details.