USB: USB keyboard usage, including LUKS passphrase

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Marek Marczykowski-Górecki 2018-02-02 01:03:44 +01:00
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@ -494,6 +494,24 @@ How to use a USB keyboard
**Caution:** Please carefully read the [Security Warning about USB Input Devices] before proceeding.
If you use USB keyboard, automatic USB qube creation during installation is disabled.
Additional steps are required to avoid locking you out from the system.
Those steps are not performed by default, because of risk explained in [Security Warning about USB Input Devices].
### R4.0, using salt ###
To allow USB keyboard usage (including early boot for LUKS passphrase), execute in dom0:
sudo qubesctl state.sls qvm.usb-keyboard
The above command will take care of all required configuration, including creating USB qube if not present.
Note that it will expose dom0 to USB devices while entering LUKS passphrase.
Users are advised to physically disconnect other devices from the system for that time, to minimize the risk.
If you wish to perform only subset of this configuration (for example do not enable USB keyboard during boot), see manual instructions below.
### R3.2, manual ###
In order to use a USB keyboard, you must first attach it to a USB qube, then give that qube permission to pass keyboard input to dom0.
Edit the `qubes.InputKeyboard` policy file in dom0, which is located here:
@ -512,6 +530,9 @@ For a confirmation dialog each time the USB keyboard is connected, change this l
sys-usb dom0 ask,default_target=dom0
```
Additionally, if you want to use USB keyboard to enter LUKS passphrase, it is incompatible with [hiding USB controllers from dom0][How to hide all USB controllers from dom0].
You need to revert that procedure (remove `rd.qubes.hide_all_usb` option from files mentioned there) and employ alternative protection during system boot - disconnect other devices during startup.
How to use a USB mouse
----------------------
@ -556,4 +577,5 @@ sys-usb dom0 ask,default_target=dom0
[usb-challenges]: https://blog.invisiblethings.org/2011/05/31/usb-security-challenges.html
[YubiKey]: /doc/YubiKey/
[Security Warning about USB Input Devices]: #security-warning-about-usb-input-devices
[How to hide all USB controllers from dom0]: #how-to-hide-all-usb-controllers-from-dom0
[qubes-usb-proxy]: https://github.com/QubesOS/qubes-app-linux-usb-proxy