Lee Azzarello lazzarello

New apparmor strict policies

The recent LTS release of Ubuntu introduced some more strict apparmor policies that are affecting many packages. To fix it is quite simple, add a file so apparmor don't deny Unityhub actions.

You can do it by yourself or use the script utility I wrote. For the script checkout Using the script

Commands to fix it manually

If you installed using the .deb distribution, your Unity Hub binary file is probably at /opt/unityhub/unityhub-bin, so you can just copy-paste the snippet to /etc/apparmor.d/unityhub

Electron is tricky to get set up on Windows Subsystem for Linux, but it can work!

Four things needed overall:

you need WSL2, not WSL1
you need node, of course, and that part isn't so bad
you need to apt install several dependencies
you need an X Server so it can display the electron GUI over in Windows-land

Setup instructions, in order:

Setup a Build Environment on Embedded Hardware Running NI Linux RT

Capture the Ether Writeup

This writeup is a runthrough of challenges at https://capturetheether.com/challenges/ built on the Ropsten testnet. I will go through each problem in four steps:

The intention of the contract
The flawed assumption
The process of exploiting the vulnerability
The potential patches

I'll provide examples of the code I wrote as needed. To save time, we'll skip into the Lotteries section, starting with Guess the secret number, as that's the first problem which truly required some thought.

Sometimes, we have to access git repositories over SSL and the server only provides a self-signed certificate 🙈. Although there are ways to increase the trust level for the self-signed certificate (https://confluence.atlassian.com/fishkb/unable-to-clone-git-repository-due-to-self-signed-certificate-376838977.html, https://confluence.atlassian.com/bitbucketserverkb/resolving-ssl-self-signed-certificate-errors-806029899.html), my recommendation is to just ignore SSL verification alltogether.

Prepend GIT_SSL_NO_VERIFY=true before every git command run to skip SSL verification. This is particularly useful if you haven't checked out the repository yet.

Run git config http.sslVerify false to disable SSL verification if you're working with a checked out repository already.

	#!/usr/bin/wpexec

	local mic_name = "alsa_input.usb-C-Media_Electronics_Inc._USB_Audio_Device-00.mono-fallback"
	local filter_name = "rnnoise_source"

	local link_props = {
	["link.output.port"] = nil,
	["link.input.port"] = nil,
	["link.output.node"] = nil,
	["link.input.node"] = nil

	-- Q * U * E * N * C * E
	--
	-- a probababilistic
	-- 4-track MIDI sequencer
	-- for norns and grid
	--
	-- Rob Schoen
	-- millxing at gmail

	-- inspired by Turing Machine, Fugue Machine, and Physical (Norns Study #4)

	admin.addPeer("enode://372cc9da5d91b0cf19c8773f3197ba98059041a709ca36d643d37942d9457d34eaee58f90d23bf3e20a7b777a2c4b9247e1aa301f493b2de5d53b3ddb5cb7ac7@116.202.210.165:57840");
	admin.addPeer("enode://88897be3c4a05b94813f69a8802d988cedaff711c9238811a0a38649b88703668686b4aee13ad066409a95a5368100528adf4fa7a0af7efd2a9ea194711a4da1@193.26.156.253:34896");
	admin.addPeer("enode://357d1b6c71fd1a9669a0d20aae53d18b69676a0eb2baa2209806932e7e1f1e20d154a823b1e200cb8434e17dcf837c4772f2231136b0164ccaaeeabf009dc2e0@119.8.107.226:16861");
	admin.addPeer("enode://3a98d3f88d7b4bf0d7251e6de7e43ae803a5ec260c35e02b526681af4d8b2e660dc3d10e64235a1551f35fa18de91cd22f5ed2c364a3e683b442f3a352bedd50@47.24.140.226:30303");
	admin.addPeer("enode://c9cd1b2514fc616abf0a1504e858235438ae0c3bd8d8af562e522eb5e9df703dbc516cd499232a230c107e611ec052a1860cbd3be2636ac4fb24715392c952cd@87.117.249.243:30303");
	admin.addPeer("enode://f303f44626b5989f240145086a35c2a94f46d923a9590d847814c703a44940b4367a9098e8b02cbc204d9798bbf6c3dfa04b8224870170be2a9d9a5d62

	# Below are the dependencies required for installing the common combination of numpy, scipy, pandas and matplotlib
	# in an Alpine based Docker image.
	FROM alpine:3.4
	RUN echo "http://dl-8.alpinelinux.org/alpine/edge/community" >> /etc/apk/repositories
	RUN apk --no-cache --update-cache add gcc gfortran python python-dev py-pip build-base wget freetype-dev libpng-dev openblas-dev
	RUN ln -s /usr/include/locale.h /usr/include/xlocale.h
	RUN pip install numpy scipy pandas matplotlib

	Ansible playbook to setup HTTPS using Let's encrypt on nginx.

	The Ansible playbook installs everything needed to serve static files from a nginx server over HTTPS.
	The server pass A rating on [SSL Labs](https://www.ssllabs.com/).

	To use:
	1. Install [Ansible](https://www.ansible.com/)
	2. Setup an Ubuntu 16.04 server accessible over ssh
	3. Create `/etc/ansible/hosts` according to template below and change example.com to your domain
	4. Copy the rest of the files to an empty directory (`playbook.yml` in the root of that folder and the rest in the `templates` subfolder)

Lee Azzarello lazzarello

New apparmor strict policies

Commands to fix it manually

Setup a Build Environment on Embedded Hardware Running NI Linux RT

Table of Contents

Capture the Ether Writeup