LaSombra lasombra

FAQ on the xz-utils backdoor (CVE-2024-3094)

This is a living document. Everything in this document is made in good faith of being accurate, but like I just said; we don't yet know everything about what's going on.

Update: I've disabled comments as of 2025-01-26 to avoid everyone having notifications for something a year on if someone wants to suggest a correction. Folks are free to email to suggest corrections still, of course.

Background

Turn auto-exposure off, set absolute exposure to a low level and use gain to compensate for low light if needed. E.g.:

v4l2-ctl -d /dev/video2 -c exposure_absolute=400
v4l2-ctl -d /dev/video2 -c gain=110

# check with
v4l2-ctl -d /dev/video2 -L

Disable Device Enrollment Program (DEP) notification on macOS Ventura.md

Ventura docs for M2 Macs in this comment: https://gist.github.com/henrik242/65d26a7deca30bdb9828e183809690bd?permalink_comment_id=4555340#gistcomment-4555340

Old Monterey docs in this old revision: https://gist.github.com/henrik242/65d26a7deca30bdb9828e183809690bd/32c410e3a1de73539c76fa13ea5486569c4e0c5d

Solution for Sonoma: https://gist.github.com/sghiassy/a3927405cf4ffe81242f4ecb01c382ac

Why?

Since it is not possible to rely on the encryption that is provided for us in our daily applications (email, chat, etc), so, I decide to create this method as an alternative to quickly send sensitive data through current chat applications, email, etc.

How?

Using openssl in both sides (the sender and the receiver) is possible to exchange encrypted messages using our preffered chat application. In this process, I tied receiver's github account with his SSH public key, that way we can believe a little bit more if the receiver is who we think he is.

Before starting

FFmpeg cheat sheet

A list of useful commands for the FFmpeg command line tool.

Download FFmpeg: https://www.ffmpeg.org/download.html

Full documentation: https://www.ffmpeg.org/ffmpeg.html

Basic conversion

Quick Tips for Fast Code on the JVM

I was talking to a coworker recently about general techniques that almost always form the core of any effort to write very fast, down-to-the-metal hot path code on the JVM, and they pointed out that there really isn't a particularly good place to go for this information. It occurred to me that, really, I had more or less picked up all of it by word of mouth and experience, and there just aren't any good reference sources on the topic. So… here's my word of mouth.

This is by no means a comprehensive gist. It's also important to understand that the techniques that I outline in here are not 100% absolute either. Performance on the JVM is an incredibly complicated subject, and while there are rules that almost always hold true, the "almost" remains very salient. Also, for many or even most applications, there will be other techniques that I'm not mentioning which will have a greater impact. JMH, Java Flight Recorder, and a good profiler are your very best friend! Mea

	#!/bin/bash
	function sdkj() {
	if [ "$1" == "" ]; then
	echo "Expected Version prefix"
	exit 1
	fi
	PREFIX=$1
	CONTAINS=$2
	# list candidates in the order they were installed. Last matching installed will be selected.
	CANDIDATES=$(ls -tr ~/.sdkman/candidates/java/)

	#!/bin/bash
	#!/bin/zsh
	# by joevt May 24/2023

	#=========================================================================================

	edid_decode=edid-decode

	#=========================================================================================
	# Modify EDID

	#!/usr/bin/env python3
	# This script is useful for setting fallback mtime for isync/mbsync CopyArrivalDate option
	# If you use notmuch then you could do something like this to fix mtime on new mail
	# notmuch search --output=files tag:new \| xargs -P0 -i ~/code/mailutils/fix_maildir_mtime.py {}

	import email
	import sys
	import os
	from email.utils import parsedate_tz, mktime_tz

	#!/bin/bash
	printf "===START dns.google.com===\n"
	curl -k -H "accept: application/dns-json" "https://dns.google.com/resolve?name=example.com&type=AAAA"
	printf "\n===END dns.google.com===\n"
	printf "===START cloudflare-dns.com===\n"
	curl -k -H "accept: application/dns-json" "https://cloudflare-dns.com/dns-query?name=example.com&type=AAAA"
	printf "\n===END cloudflare-dns.com===\n"
	printf "===START 1.1.1.1===\n"
	curl -k -H "accept: application/dns-json" "https://1.1.1.1/dns-query?name=example.com&type=AAAA"
	printf "\n===END 1.1.1.1===\n"