In Debian (and Ubuntu), when using a LUKS encrypted volume with cryptsetup, there is a documented option in the manpage for /etc/crypttab called keyscript : it should allow the init system to launch a program and have its standard output used as a key to unlock a volume. But there …
This was originally published as a thread on Mastodon . For fun I implemented lbzip2's lbzcat (parallel bzip2 decompression) clone in rust , using the bzip2 crate. Baseline: bzip2 vs bzip2-rs First, let's look at the baseline. The Trifecta Tech Foundation recently claimed that bzip2-rs had faster decompression than libbzip2's original C …
It all started with this really simple nerdsnipe by Joachim (french) : How many clicks would it take to go from the Wikipedia pages of (southmost Metropolitan France town) Cerbères to (northmost France town) Bray-les-Dunes, using only Wikipedia's "adjacent communes links" ? Quite a simple question. Many surprises. Querying Wikidata So, we …
Advent of Code is an Advent calendar of small programming puzzles. I participated in this year's edition , finishing it for the second time in row. The puzzles of all editions are always accessible. The principle is to read the problem, get a puzzle input (more or less tailored to your …
I have released a small application, hashtag-importer , that users of a Mastodon instance can use to slowly import more content from low-traffic hashtags, into their instance (with their admin's permission). Why hashtag-importer In the fediverse, your server might not see all posts made by everyone; it should only see posts …
Previously , I had a bug in my gears emulator , which I then fixed . But Sonic 2 still wasn't working, so let's see what went wrong there. Missing interrupt behaviour The Sonic 2 ROM wasn't starting at all, leaving an uninteresting black screen, which led me to suspect some kind of …
Previously , I had a bug on my emulator with the way the map is rendered. With the bug How it should look like After I wrote the previous article, I posted it on the SMS power discord, asking for ideas on this corruption bug. Many great people chimed in. A …
I wrote here about how I'm writing an emulator . How has it progressed ? Fixing a rendering bug with backgrounds In November I wrote on mastodon how I was tracking down a rendering bug. To track down this issue with weird data on screen, there was already too many messages, so …
In 2019 I gave a talk at FOSDEM in Brussels on the "music portal" , a device I built for my children as a toy that plays music. I wrote about the first version in awk here . The talk revolved around the specifics of the Go language and how it was …
I've been using a french dvorak-like key layout, called bépo for about 13 years; sometimes, I need to hack things around to have it work everywhere, like when I wrote support for it android physical keyboards . GPD Win Max Adaptation I acquired recently a GPD Win Max , which is a …
I recently updated the server where this blog is hosted, so I tought I'd do an update on the original post explaining the tech stack used to run it. Once in seven years shouldn't be too meta. The design First of all, kudos to Pascal Navière , a very talented polymath …
Gmail used to be the reference for "infinite email storage". Not anymore. The space growth stopped, and then Google started selling storage space. It wouldn't be an issue if it were easy to mass delete emails; unfortunately batch delete operations can be quite long, and even lock you out of …
This has been brewing for a while, but I finally put it into words during this pandemic: if you're an embedded software engineer, the ability to work remotely (without the hardware next to you) is in fact a sign that you have reached a certain level of software engineering maturity …
I noticed recently how little I knew about IPv6. For someone working on broadband gateways, that's not something I'm most proud of. But I've learned a little in the past few months, and I thought I'd share it here. How to read an IPv6 address: the zeroes are hidden An …
I’m at CCC for the first time this year ! Here my notes for a few of the talks. Tamago In an ideal world, one could pick the programming language of their choice and always generate the optimal machine code. But we live in the real world, and it isn't …
Following my ELCE notes , you'll find below my notes for some of the talks the Linux Security Summit Europe 2019. Exploiting race conditions using the scheduler — Jann Horn The first bug Jann talked about is a race between mremap and fallocate. mremap allows moving a memory mapping from an address …
After a two years hiatus, I couldn't miss this year's ELCE happening in Lyon, the first in France since 10 years ago in Grenoble, which coincidentally was one of my first conferences. OS Summit and KVM forum events are co-located and with the same ticket, which is nice, and why …
This was previously published on LinkedIn Until very recently I couldn’t really answer this question. But it has shipped, so now I can tell you: I've been working on Edge Computing. To be more precise, this is the first compute service available to ISP subscribers directly on their ISP …
You might have noticed I was at r2con 2019 . This is my writeup for the r2wars 2019 challenge. r2wars primer: a Core Wars-like game In radare2, there's an intermediate language and VM called ESIL. It is used to emulate code, and supports many architectures. r2wars is built on top of …
I'm back in Barcelona for this year's edition of r2con . You can read my r2con 2018 report . radare2 is debugging and reverse engineering toolkit. It's mostly used from the command line or through a programming interface (r2pipe) that is identical to the command line one. Cutter Cutter is the official …
This year I'm at the Pass the Salt 2019 conferences. You'll find my part 1 and part 2 of my notes here . Configurations, Do you prove yours ? by Alexandre Brianceau ( slides ) Alexandre went a bit more into details on the core concepts behind DevSecOps, and why continous configuration and observability …
This year I'm at the Pass the Salt 2019 conferences. You'll find my part 1 of my notes and part 2 here. Time-efficient assessment of open-source projects for Red Teamers by Thomas Chauchefoin and Julien Szlamowicz ( slides ) In their pentest team, Julien often does red team assessments with big scopes …
This year I'm at the Pass the Salt 2019 conferences. You'll find my notes updated in real time here. Kill MD5 by Ange Albertini ( slides ) Ange starts by saying that he does not know much about crypto, and he had help from Marc Stevens, a hash-collision cryptographer. This talk should …
2004 Gmail recently celebrated its 15 years anniversary, which led me down the path of how I got my first gmail invite. Back then, the private Gmail beta was all the rage. In the first few months, gmail invites were scarce . I got one by doing the most popular thing …
I recently took the plunge and decided to move to fish , a friendly modern shell. Background I'm heavily invested in bash. I wrote countless scripts, for my personal use, and for various jobs or projects, so I didn't think it would be an easy thing to move away from it …
Scaleway, a french cloud provider, has been renting baremetal ARM servers for a few years now, and virtual ARM64 servers more recently. They ship with a scaleway-provided kernel and initird, which isn't updated as often as I'd like. The latest ARMv7 (32 bits) kernel, is 4.9.93, while the …
After my r2con r2wars writeup , here's another writeup of a "challenge". This challenge is the Capture-The-Flag (CTF) pre-qualifications for the SIGSEGV1 conference in Paris . It felt a bit weird to have a conference registration limited to those who pass a certain challenge, but I was curious about what it would …
I had a lot of good feedback from the previous years live-blogs of the Embedded and Kernel Recipes conferences. So much in fact, that this year I'm now doing the liveblog directly on the official website of kernel recipes . I hope you enjoy it ! I also live-tweeted my impressions of …
I tried something new this year, by going to r2con , a conference dedicated to radare2 , a reverse engineering toolkit. r2con This conference is one of the most affordable security conference out there. I've used radare2 (r2) in the past, but I don't think I fully understood its philosophy until going …
This is continuation of day 1 and day 2 of Kernel Recipes 2017. Using Linux perf at Netflix by Brendan Gregg Brendan started with a ZFS on Linux case study, where it was eating 30% of the CPU resources, which it should never be doing. He started by generating a …
This is continuation of yesterday's live blog of Kernel Recipes 2017. Linux Kernel Self Protection Project by Kees Cook Presentation slides The aim of the project is more than protecting the kernel. Background Kees' motivation for working on Linux, is the two billion Android devices running a Linux. The majority …
Following last year attempt , I'm doing a live blog of Kernel Recipes 6th edition. There's also a live stream at Air Mozilla What's new in the world of storage for Linux by Jens Axboe Jens started with the status of blk-mq conversions: most drivers are now converted: stec, nbd, MMC …
Following last year attempt , I'm doing a live blog of Embedded Recipes 1st edition. Understanding SCHED_DEADLINE by Steven Rostedt Every task starts as SCHED_OTHER, where each task gets a fair share of the CPU bandwidth. Then comes SCHED_FIFO, where it's first in, first out, a task will run until it …
With a Raspberry Pi or other modern single-board computers, you can make very simple toys. I started with the hello world of interactive apps: the soundboard . But even then, I was too ambitious. The soundpad Since the main target was kids. I wanted a simple, screen-less toy that would teach …
For the Go 1.8 Release Party in Paris I gave a lightning talk on monotonic clocks. It's essentially a talk version of the Russ Cox's design document on monotonic clocks , which is really well written and sourced. You should go read it ! Here are the slides export and their …
I was in Berlin last week for ELCE, and it was great. It was a nice mix of talks on many different subjects, and as always you come back with lots of new ideas and improved motivation. As you know, I took some notes for Kernel Recipes 2016 , and lots …
Update 2016-10-21: I've added links to the videos and LWN articles , which are of much higher quality than these live notes. This year I'm trying a live blog of Kernel Recipes 2016 , live from Paris, at Mozilla's headquarters. You can watch the live stream here . The kernel report by Jonathan …
This is a followup to What do you find when you search Twitter for hashes ? Why ? I'm not sure I remember how it started. It all started four years ago. Jon Oberheide was still an independent security researcher and not yet CTO of a successful product company. He posted some …
This image: This is what I found with hashbot, a twitter bot that looks for hashes. What is this image ? Posted with the hash "2f404a288d1b564fadee944827a39a14" by japanese accounts (of which @furueru_zekkei used to be the top poster, now suspended). After a bit of research on google images and more, I …
I wanted to try my hand with ESP8266 modules, so I got a witty cloud development board . It's running a proprietary firmware from gizwits which I backed up if anyone wants to look at it. The board is in two parts: programming board("cape") with ch340g usb serial and 3 …
This is a small project I recently released on github and Google Play . It aims at catering to the needs of people using the bépo layout, and wanting to use it for physical keyboards on Android . Bépo is a french dvorak-like keyboard layout; it was designed by a community of …
So I have this NAS made by my ISP, that does a lot of things; but recently, I started having issues with its behavior. Recorded TV shows had lag/jitter while replaying, and the same happened with other types of videos I put on it. I narrowed it down to …
So I was in Edinburgh this year, and I took notes as I usually do. These are intended for personal consumption (do no expect LWN-style reports), but as more people were asking me to share them, I thought why not do it in public ? Embedded Linux timeline by Chris Simmonds …
Update : I updated the information below with the 2020 tech . So I finally did it. You're reading it right now. My personnal website/blog. I should be posting here about things that cross my mind as well as various projects I've been working on. And maybe even new projets I …