RDP at Home

We want to operate the firefox on the desktop in the study (connected to the TV with an HDMI cable)…

… from the couch in the living room.

Why is this an issue? Well, our study is separated from the living room by a sliding door that includes the TV - so pausing a movie or changing the volume involves a walk to the study (and the shortest route involves sliding away the TV), an inconvenient interruption.

A straightforward solution should be to connect our (Windows) laptop(s) to the (Linux) desktop using Remote Desktop. GNOME Remote Desktop should enable just that, but it is, well, pre-alpha; not yet ready for use in my desktop environment (FC33).

Here’s the steps to make this work!

Sharing settings

The first step is to turn GNOME Remote Desktop on/off through the Screen Sharing dialogue, under Settings / Sharing / Screen Sharing in the menu.

Choose a password, pick one that is different from your normal login password.

Switching the slider in the Sharing settings is equivalent to entering the following from the command-line:

systemctl --user start|stop gnome-remote-desktop.service

TLS settings

The second step is to make the Windows client connect to the Linux server without connection errors. I did not yet find out whether it is the Windows RDP client that forces the use of TLS 2.0 or whether this is a requirement in the GNOME Remote Desktop server, but you must provide a key for the server.

The following is a workaround that needs improvement. I have - temporarilly - created self-signed certificates server.crt and server.key.

Getting things to actually work creates a minor security issue: because the user runs gnome-remote-desktop (and not root), the file storing the server’s private key must be user-readable:

sudo chown $USER /etc/pki/tls/private/server.key

Use dconf-editor to set the following values, or use the CLI:

gsettings set org.gnome.desktop.remote-desktop.rdp tls-cert  '/etc/pki/tls/certs/server.crt'
gsettings set org.gnome.desktop.remote-desktop.rdp tls-key   '/etc/pki/tls/private/server.key'
gsettings set org.gnome.desktop.remote-desktop.rdp view-only "false"

RDP credentials

Once I got this far, I discovered that the UI/UX for controlling access is unfinished or missing.

When trying to connect to GNOME Remote Desktop you see the following errors in the log (journalctl -rx): gnome-remote-de[XXX]: Couldn't retrieve RDP username: Credentials not set.

The problem is that grd-settings.c (code) looks for user credentials using libsecret; the VNC password in org.gnome.RemoteDesktop.VncPassword is set correctly using the Screen Sharing dialogue mentioned above, but the option to control org.gnome.RemoteDesktop.RdpCredentials is still missing from the UI.

Initially, I attempted to mimic the VNC values using seahorse and/or secret-tool, but to no avail. After trying many different failed methods to get the credentials into the user environment in the right way, I ended up reverse engineering the solution from the code and writing a simple yet-not-robust python script to create these values correctly (the server code is still fragile and crashes upon incorrect values).

Download RDP-set-credentials.py from this repository and issue the following command:

python RDP-set-credentials.py $USER vnc-password

The password should correspond to the one given under Access Options in the Sharing dialogue.

Update:

Three months after writing this, the GNOME team has provided a similar workaround at this GNOME snippets.

Next steps

Use-case watching online films from the couch has been solved! Unfortunately, only mouse input works - after puzzling on some warnings and errors, RedHat’s Jonas Ådahl confirmed that keyboard input is incomplete.

So… what if I really need my keyboard?

Walk over to the study, you lazy b@st@rd! Oh, and, GNOME Remote Desktop works fine with VNC clients too! Only slower.