Linux Desktop

January 2021

Reverse Engineering fun for just 9.33 € + shipping

This article is a brief introduction to the reverse engineering of a Bluetooth LE Temperature and Humidity sensor and data logger. This is done, according to the EU reverse engineering law, only for interoperability purposes. The device is called SensorBlue or ThermoBeacon or ORIA on Aliexpress and here is a photo of what you get: You can download an Android application to get you started and test the device. Next we will see some tools useful to inspect a Bluetooth device.

Android Linux Desktop

3 minutes

May 2020

Notes on using a TPM2 module on Linux

Here I collected some notes on using the TPM2 on Linux, specifically Arch Linux. The motherboard used is an ASRock E3C222D4U with the ASRock TPM2 module. This article focuses on enabling the usage of the keys stored in the TPM2 by various tools using the PKCS#11 interface. The module should be configured to allow the access to these keys only after some measurement of the state of the system is done, to guarantee that it was not tampered.

Linux Desktop

7 minutes

January 2017

YAACA, Yet Another AstroCam Application

Yaaca is an application to acquire images from ZWO ASICams and apply various astronomical image processing to them. It is available and documented on yaaca github page. Here are some examples.

Astronomy Linux Desktop

1 minute

April 2016

Using Google Nik Collection with GIMP under Linux and WINE.

Ideally we should have Free Software that serves our needs, but sometimes we must settle for a temporary solution. Google Nik Collection is now free as in free beer, some of its filters are just amazing and it is pretty straightforward to use. It is not difficult to make it work as a GIMP plugin on Linux, even if it is for Windows, thanks to WINE.

Linux Desktop

4 minutes

August 2014

Per process routing take 2: using cgroups, iptables and policy routing

In a previous article we saw how it’s possible to do per process routing using namespaces. In this one we will achieve the same by using cgroups, iptables and policy routing. Perhaps the user case is a bit marginal (see the introduction in the mentioned article) but this article is a tribute to the extreme flexibility of cgroups.

Cgroups Iptables Linux Desktop Netfilter Policy Routing

6 minutes

November 2013

Using Linux Network Namespaces for per processes routing

The use case for this article may seem a bit strange in year 2013 but I swear it’s real. I have a (relatively) fast connection but I have a traffic cap on it and a (really) slow one which is flat. I would like to run not interactive task like “aptitude safe-upgrade” on the slow one but the bulk of my connections should go through the fast one. The work is done on a Debian Wheezy system, check that the “ip” command is not too old and lacks network namespace support.

Linux Linux Desktop Namespaces Networking Routing Sysadmin

7 minutes

April 2013

TOR+Privoxy minimal setup for DGN2200v3/MIPS architecture

In a previous article I talked about how to customize the Linux based WLAN+ADSL Netgear DGN2200v3 router and prepared various binary packages ready for the device. In this short article I’m offering a small full setup that can be run on this router (and many other compatible ones and in general on any MIPS+uClinux hardware setup) to be able to use easily the TOR network to browser anonymously. In this way all the users behind the router can easily achieve anonymous surfing.

Anonymizer Anonymous Surfing Dgn2200v3 Embedded Linux Linux Desktop Linux Embedded Mips Security Teaching Material The Onion Ring TOR Transparent Proxy

5 minutes

Command line PHP deobfuscation

Recently a customer asked me to debug some problems on their Joomla!/PHP site that had interoperability issues after some long time for unknown reasons. The site was using some commercial plugins which producer was long time gone and unreachable and worst of all they were all obfuscated. So even searching for some basic string that was displayed on the screen on error to understand what’s going on was not a straight forward exercise and going through the code was a mess. Apart from changing the code in a logical way, for example by adding intermediate variables or splitting variable assignations into more operations and so on, the first most annoying part of PHP obfuscators is that they modify most of the characters in the strings values with their respective hexadecimal (format \xXX) or octal (\XXX) values and eliminate any line feeds or code structure. Once you get rid of this the code stays quite very messy but is, at least in the cases I analyzed, quite readable and just needs a little more bookkeeping with automatically named vars to go through. Getting rid at least of this confusing representation is quite straightforward on the command line with a few tricks.

Command Line Deobfuscation Linux Desktop Php Reverse Engineering Security Teaching Material

4 minutes

January 2013

pyargocat: Argo Navis Catalog manager in Python

 pyargocat is a small simple Python script that can be used to program the catalogs of the Argo Navis Digital Telescope Computer from a machine with a recent Python interpreter installed using the RS232 cable that you can either buy or easily construct yourself. pyargocat can manage, that is insert to the device, all three types of catalogs in the device (asteroids, comets and user defined objects), report the number of objects present, report available space and delete previously flashed catalogs. It can be used on any machine with a Python >= 2.7 installed and it has been tested on Linux and Windows machines. The imported catalogs have to be in the standard format Argo Navis uses (please refeer to the Argo Navis manual for the details and for links to useful resources). As an example and as a possible useful addition for your advanced observing sessions you can download this sample file I created that I often use as a basis: fede-general.txt. (the file contains all the Abell planetaries, the complete ARP catalog of Peculiar galaxies, the Hickinson galaxy groups catalog, most of the PK Planetary Nebula catalog and a selection of particullar globular clusters such as the Palomars and Terzans). Also a comet database file is given as an example with the most interesting comet objects data at the time of writing: Comets.txt Download: pyargocat-0.1.tar.gz.

Argo Navis Astronomy Linux Linux Desktop Python Science

3 minutes

How to cross-compile under Linux

Recently I’ve been asked by a few people how to crosscompile programs/packages under Linux. This happened especially after the article on customizing the DGN2200v3 (you can find here) but also for work reasons. In this article I’ll try to give some insights on this operation that is often feared, but is generally not a very hard task (yes I said generally: try for example crosscompiling something like the openjdk and you’ll understand what I mean!). This article will try to be generic but with some more examples on the DGN2200v3 crosscompilation and some ARM references. Get and install the right tools The first thing to do if of course to install on the system you are working (which is called host system) the tools that run on the host and will permit you to compile something for the target system you want to compile the programs for. This set of programming tools is usually refeered as a toolchain and contains various things: usually one or a few compilers, one or a few linkers, an assembler, various header files, little or a lot of libraries and other simillar tools. If you are lucky you may get also a debugger packed. All this tools of course are compiled to run on your host machine but produce binaries that run on the target. Depending on how the toolchain was created you may also find supplied with it some set of tools that are ready to be run on the target to help your crosscompilation adventure. This operation may be very easy if you somehow received the crosscompiler package ready (as for example the DGN2200v3 you just download it from the Netgear site or you collegue may have passed it to you) as you just have to unpack it somewhere and then refeer to it.

Arm Compile Cross Crosscompile Dgn2200v3 Embedded Linux Linux Desktop Linux Drivers Linux Embedded Mips

11 minutes

November 2012

Customizing your Netgear DGN2200v3

The Netgear DGN2200v3 is a nice low cost Wireless (802.11b/g/n) ADSL2+ router that can be quite easily found. It is a nice piece of hardware and features some interesting features, such an USB host port to connect and share a USB storage device, and expecially is easily customizable for users interested in having a powerfull generic device running a Linux embedded operating system. Note: this is a heavily “Work in Progress” page so please check it out here and there if you are interested in the topic! (last update 09th June 2014) First of all you can find the source tree for the router at Netgear site starting from their GPL Open Source Code for Programmers page. The package also contains a suitable toolchain uclibc-crosstools-gcc-4.4.2-1. Everything described in this page refeers to the “official” firmware V1.1.00.10_1.00.10 . It may also apply to future updates and to the beta version that Netgear started to distribute but it may require slight modifications. The next step to access to your router internals is to enable the telnet shell using the debug backdoor present in the firmware. It is easily done by accessing (we suppose is your router IP address) the URL: This will enable telnet connections from your local network. Just login with your administrator credentials. Once you entered you can analyze the running system, briefly:

Custom Customizing Dgn2200 Dgn2200v3 Embedded Firmware Hacking Linux Linux Desktop Linux Embedded Mips Netgear Screen Torrent

87 minutes

October 2009

Using Slovenian characters on an Italian keyboard

An article on how to use Slovenian characters under a Linux/GNU/X11 system. (in Slovene)

Desktop I18N Linux Linux Desktop Slovene X11

1 minute

March 2001

Enjoying Computers, Discovering Linux

An article about the course based on the ECDL syllabus based on Linux and open-source tools organized for high-school teachers published on Linux Journal Online.

Ecdl Linux Linux Desktop Open Source Teaching Teaching Material

1 minute