mudbugos/DOCUMENTATION.md

PrawnOS Documentation

Some additional documentation for PrawnOS that wouldn't fit in the README

Useful XFCE4 keybindings and libinput-gestures:

Gestures:

Config file: /etc/libinput-gestures.conf

• four finger swipe left: Switch to left workspace
• four finger swipe right: Switch to right workspace

Keybindings

Configure under Settings->Window Manager->Keyboard

• control+alt+left: move window to left workspace

• control+alt+right: move window to right workspace

• alt+left: tile widow to the left

• alt+right: tile window to the right

• alt+up: maximize window

• alt+tab: app switcher

Configure under Settings->Keyboard->Application Shortcuts

• alt+space : App launcher (spotlight-esque)
• control+alt+l: Lock screen
• Brightness scripts are also called here and can be remapped here or in ~/.Xmodmap

Configured using xkb

• "search" key: function (fn) key

• fn + backspace: delete

• fn + up: page up

• fn + down: page down

• fn + left: home

• fn + right: end

• fn + "brightness up key": increase backlight

• fn + "brightness down key": decrease backlight

• fn + "volume mute": mute volume

• fn + "volume down": decrease volume

• fn + "volume up": increase volume

Initramfs and Encryption

PrawnOS uses a custom initramfs, custom init script, and dmcrypt/LUKS to enable full root partition encryption

Because the c201s bootloader, depthcharge, can't be given dynamic cmdline parameters like grub we can't use the "usual" method of setting up an initramfs. Essentially, we can't boot from an initramfs image stored on a /boot partiton

Either the initramfs needs to be built into the part of the kernel image passed to depthcharge using a kernel.its similar to this one by @ifbizo:

/dts-v1/;

/ {
	description = "Linux-libre kernel image with one or more FDT blobs";
	#address-cells = <1>;
	images {
		kernel {
			description = "vmlinuz";
			data = /incbin/("/boot/vmlinuz-SED_KVER");
			type = "kernel_noload";
			arch = "arm";
			os = "linux";
			compression = "none";
			load = <0>;
			entry = <0>;
			hash {
				algo = "sha1";
			};
		};
		fdt {
			description = "dtb";
			data = /incbin/("/boot/rk3288-veyron-speedy.dtb");
			type = "flat_dt";
			arch = "arm";
			compression = "none";
			hash {
				algo = "sha1";
			};
		};
		ramdisk@1{
			description = "initrd.img";
			data = /incbin/("/boot/initrd.img-SED_KVER");
			type = "ramdisk";
			arch = "arm";
			os = "linux";
			compression = "none";
			hash@1{
				algo = "sha1";
			};
		};
	};
	configurations {
		default = "conf";
		conf{
			kernel = "kernel";
			fdt = "fdt";
			ramdisk = "ramdisk@1";
		};
	};
};

Or it needs to be built into the kernel using the kernel config parameter CONFIG_INITRAMFS_SOURCE="PrawnOS-initramfs.cpio.gz"

For PrawnOS I decided to go with building into the kernel to avoid relying on the bootloader, the bootloader may change but the kernel will always support booting an initramfs image.

The script buildInitramFs.sh creates the PrawnOS-initramfs.cpio.gz image that is then used by buildKerenl.sh, copying all of the tools and libraries the initramfs needs from the built filesystem image.

The initramfs is what runs initialy at boot, and allows us to enter a password and decrypt the root partiton

In a normal system, when dmcrypt/LUKS is setup the initramfs image is modified to enable decrypting of the root partiton

Since we have to have a static initramfs image, and can't change it without recompiling the kernel, we detect whether encryption is in use by checking for the tag crypto_LUKS on the root device at boot.

debugging the init script

A rescue debug shell is entered when the init script encounters a problem, or if a device with the partition label RESCUESHELL is present

Label any partition on the system with RESCUESHELL to enter the initramfs rescue shell before mount and root_switch.

You can do this with cgpt add -i 1 -l RESCUESHELL /dev/sda for example to label the first partiton of a usb drive.

This is the suggested method, as then debugging can be enabled/disabled by plugging in/removing the usb device.

PrawnOS APT repo

https://deb.prawnos.com

Key management

apt repo holds a short life signing private key, and the long life master public key the short life signing key is a sub key of the master key This way we can safely keep the master key off of any distribution servers. This also allows us to revoke the signing key and issue a new one all without users needing to update their key store, as the master public key will be valid for all sub keys

importing/exporting was done based off of https://www.debuntu.org/how-to-importexport-gpg-key-pair/

subkey creation instructions found here https://www.digitalocean.com/community/tutorials/how-to-use-reprepro-for-a-secure-package-repository-on-ubuntu-14-04 under the "Generate a Subkey for Package Signing" section

Uploading packages to deb.prawnos.halemmerich.compression

use dput user ~/.dput.cf

[deb.prawnos.com]
    fqdn = deb.prawnos.com
    method = scp
    login = debian
    incoming = /var/www/repos/apt/debian/incoming
    allow_unsigned_uploads = true
    ssh_config_options = Port=2222

upload the package

dput deb.prawnos.com *.changes