# sys-print Printer environment in Qubes OS. ## Table of Contents * [Description](#description) * [Security](#security) * [Installation](#installation) * [Access Control](#access-control) * [Usage](#usage) * [Add a printer](#add-a-printer) * [Print](#print) * [Credits](#credits) ## Description Creates a print server named "sys-print" and a named disposable "disp-sys-print" qube for sending files to your configured printer, which can be done over the network or with IPP-over-USB. ## Security The client does not have CUPS, does not need internet connection and does not have USB devices connected. Using CUPS in a dedicated qube reduces attack surface and has a better usability as you only need to configure the printer in one qube and other qubes will have access through Qrexec. If the devices connected to the server qube can attack the CUPS server, it can escalate the attack to the client qube. Usage of disposables servers does not prevent this from happening, it just avoids persistent infection on the server, where you could attribute different printers to different levels of trust. Sending files to the print server with `qvm-copy` is always safer than allowing a direct connection from the qube that wants to print files to the qube that has access to the printer. ## Installation - Top: ```sh sudo qubesctl top.enable sys-print sudo qubesctl --targets=tpl-sys-print state.apply sudo qubesctl top.disable sys-print sudo qubesctl state.apply sys-print.appmenus ``` - State: ```sh sudo qubesctl state.apply sys-print.create sudo qubesctl --skip-dom0 --targets=tpl-sys-print state.apply sys-print.install sudo qubesctl state.apply sys-print.appmenus ``` If you want to install all printer drivers: ```sh sudo qubesctl --skip-dom0 --targets=tpl-sys-print state.apply sys-print.install-driver-all ``` On the client template: ```sh sudo qubesctl --skip-dom0 --targets=TEMPLATE state.apply sys-print.install-client ``` The client qube requires the split Print service to be enabled: ```sh qvm-features QUBE service.print-client 1 ``` ## Access Control **_Default policy_** (qusal.Print RPC service): - Clients with tag `print-client` are `allowed` to call servers with tag `print-server`, defaulting to `sys-print`. - `All` clients can `ask` servers with tag `print-server`, defaulting to `sys-print`. `Asking` can spawn multiple requests depending on the client, usage of `allow` is recommended for trusted clients. Add the tag `print-client` to the qube requesting the print content: ```sh qvm-tags QUBE add print-client ``` As the call will default to `sys-print`, you can enforce the use of `disp-sys-print` via policy and not any other qube: ```qrexecpolicy qusal.Print * @tag:print-client @default allow target=disp-sys-print qusal.Print * @tag:print-client @anyvm deny ``` ## Usage ### Add a printer You will configure your printer from `sys-print` or `disp-sys-print`, it can connect over the network or USB. If you do not want to save printing configuration, use `disp-sys-print`. On `sys-print` or `disp-sys-print`, add your printer: ```sh system-config-printer ``` ### Print On the client, select the file to print, open it with an editor, viewer or browser and target the desired printer. ## Credits - [Unman](https://github.com/unman/shaker/tree/main/sys-print)