Linux User & DeveloperNo. 182的目錄

Welcome to the UK and North America’s favourite Linux and FOSS magazine. In the UK, a proposed new Data Protection Bill has caused a stir. Among many things, this bill will make it easier to withdraw your permission for social media to harvest your data; easier to access what data companies hold on you; and enable the right to be forgotten. In contrast, it will also allow parents to give consent for their child’s data to be used. I doubt we’ll have to wait long for that to be abused. Roll up, roll up! Free tickets to Legoland, if you sign little Johnny’s consent form today… Modern life offers up many such tempting traps, but in LU&D we’ll show you how to build your own in the form of honeypots…

1 KDE Plasma “A stable workspace that the user can trust” is the end game for KDE Plasma, as revealed in a statement this month. They plan to “enable actual work to happen, across devices, across different platforms, using any application.” This includes the mobile space, where work continues on the Plasma Phone platform. 2 Purism Known for trying to build a laptop with only 100 per cent FOSS applications, a webpage that was accidentally published on the Puri.sm website indicates that they’re also planning an imminent push into the mobile marketplace, following a stated desire for a Linux phone. 3 Ubuntu Phone Lives On Thanks to the UBports.com project, the most successful Linux phone to date (Android notwithstanding) has life beyond Unity. Currently, 13 devices can run Ubuntu Touch,…

It’s one of the oldest browsers still out there, but things aren’t looking great for the desktop version of Mozilla Firefox. Recent figures from StatCounter (verified by former Mozilla CTO Andreas Gal’s research) show that the number of Active Daily Installs of Firefox has fallen heavily since 2016 (with a small recovery later that year). Gal’s research shows that the desktop browser – at one time a very popular alternative to Microsoft’s dominant Internet Explorer, and a regularly installed piece of software in the Linux space – is “falling off a cliff”. The reason, says Gal, is simple: Google Chrome. Google’s aggressive marketing of its Chromium-based browser via every Google service you can think of (YouTube, Gmail, Google Drive and so on) is pulling users with the implied promise of…

“System76 has spent over a decade designing high-quality Linux computers that are consistent, user-friendly and a joy to use. When we asked Carl Richell, CEO of System76, how the company achieves such effortless consistency, he rather coyly replied “tons of automated and human testing”. Anyone who spends time testing Linux distros on different hardware knows that’s quite an understatement, but System76 is on a mission: it believes in what it’s doing, believes details matter and that Linux hardware, as well as software, should be for humans. It’s 2005 and you’ve just formed System76. The reseller market isn’t for the faint of heart, so what made you decide to focus on Linux and open source? I had a great appreciation for Linux and open source. I believed then, as I do…

01 Introducing T-Pot T-Pot combines honeypots Conpot, Cowrie, Dionaea, ElasticPot, eMobility, Glastopf and honeytrap with Suricata (a network-monitoring security engine). It visualises the collected data with ELK stack (Elasticsearch, Logstash and Kibana), which has a beautiful visualisation engine. T-Pot runs every daemon in a Docker container for good insolation. 02 Requirements and installation T-Pot can be installed on a physical computer or in a VM using different setups. To avoid any issues during installation make sure your system meets the following spec: 4GB RAM (8GB recommended), 64GB hard disk (128GB recommended) and a working internet connection. Installing T-Pot is easy: just download the ISO file from http://community-honeypot.de/tpot.iso and run it in your designated setup. 03 Running T-Pot The install takes about 30 minutes and will reboot. The user is tsec…

In this tutorial we look at the brute-force cracking of hashes, which are used as an alternative to storing passwords in cleartext. The idea is that we run our password through a cryptographically sound hash function, which returns a fixed-length alphanumeric string. Thanks to the one-way nature of good hash functions (it’s easy to calculate the hash of a password, but very difficult to recover the password given just the hash), it should be safe to store these hash values as is. However, as computing power increases and weaknesses are found in hash functions, this assumption becomes more and more fallible. For example, it’s easy to generate the hashes of all lower-case passwords less than, say, six characters, calculate their hashes and compare these to the one you wish to…

The Java programming language is packed full of features that you can use in your day-to-day programming. In this tutorial series, we’ll be showcasing a range of programming constructs, libraries and external tools for Java by building a simple sandbox-style game in which a player walks around a map collecting eggs which hatch into various animals. If you know the basics of Java programming, but have never delved into some of the more advanced tools, then this tutorial series is for you. If you have met some of these concepts before, we hope that you will still learn something new by working through the exercises. Each month, we’ll supply a codebase for you to extend. For this first article we have a very simple piece of skeleton code, and your…

01 Check disk settings When you first run your Linux distro, you may find that the installer is unable to see the main disk in your machine. This is normally because your disk mode is set to RAID rather than AHCI. This can be configured in the UEFI setup, but be aware that you’ll need to manage the change on the Windows side too (see the main text for further details), or you won’t be able to boot. 02 Create space You can free up space for your new distros either using the partitioning options in the installer or by booting up a dedicated partitioning tool such as GParted. We advise the latter, as it gives you more visual configuration and leaves you less susceptible to making an error. You…

Communication is as broken as everything else internet-related. Some of your friends are on WhatsApp, some colleagues are on Slack channels. Most people are on Twitter, but not all. Matrix brings group – or one-to-one – conversations across silos, providing a monolithic, consistent spec with a baseline API of HTTP and JSON, and a range of clients to suit different users, plus end-to-end encryption (with trust per device, not per user). Matrix is an “open standard for defragmenting communication,” through a meta-network providing an open platform for real-time communication. That can be video, audio or text chat. There are also VR/AR options available, and it can be used with anything that has persistent data that can be passed over pub/sub (publish-subscribe pattern), such as IoT-collected information. Matrix has a decentralised…

Last issue, we started our series on Minecraft pixel art, by coding some 2D art blocks. This time we’re taking a different approach to our art, by implementing an additional axis and therefore bringing it into the third dimension. Well, technically, everything is 3D in Minecraft, but last issue we built some rather convincing ‘flat’ pixel art. Now we’re taking it to the next level. We’re going to build a pyramid using while and for loops in Python. This will save us typing lots of similar lines of code. Spawning our coded creations is so much faster than placing each individual block manually in Minecraft’s Creative mode. If you’re using Minecraft Pi edition on a Raspberry Pi, no additional software is necessary. We’ve also put together a number of tools…

"Object identification is broken into stages" This issue, we’ll look at using OpenCV to add on-board image processing and object recognition to your project. To install OpenCV, use the following command: This will install the Python wrappers for OpenCV. You will, of course, also need a camera to capture the imagery for processing. While you can use a USB camera, for this tutorial we’ll assume you have the official Pi Camera Module attached. To use it, enter sudo raspi-config, select ‘5 Interfacing Options’, then ‘P1 Camera’ and select <Yes> to enable the camera. The first step is to actually collect an image. With the Pi Camera Module, you’ll need to import several classes to handle this part: Once you have an image loaded, you can start image processing and trying…

RAM 1GB Storage 10GB Specs 1GHz processor, 32- and 64-bit AMD/Intel Available from https://getfedora.org After several delays with redrawn deadlines and harried developers, Fedora gets its first release of 2017 seven months into the year. But that’s about all the excitement you’re going to get from this release. Unlike the good ol’ days, new releases, especially from top-tier projects like Fedora, don’t offer much drama – every rough edge has been polished, every flaw smoothened and refined. For a distro that’s meant to be the test bed for Red Hat’s enterprise offering, Fedora is much too conservative with its software choices. One of the highlights of the latest release is a new partitioning tool that’s been under development for a couple of years! The new partitioner called Blivet-GUI shows up…

Performance remains at the core of Julia’s purpose, maintaining its focus here as Couchbase does in the NoSQL world. And this year the Celeste project used Julia to “achieve over 1 petaflop of compute power […] on the Cori supercomputer.” It’s the modern Fortran and will work with libraries from that language – as well as C and Python – but is much more fun to use. The biggest influence is Common Lisp, while Julia’s multiple dispatch owes more to Dylan, but never mind the piecemeal comparisons, let’s install it. We grabbed the 64-bit binary package, untarred it and installed in the ~/bin directory. Julia has a REPL (Read-Eval-Print-Loop), which supports tab completion and is useful for trying out code snippets – indeed, it’s hard going back to languages that…

Butler Johnson, the personalised artificial intelligence that ran every aspect of Ms Johnson’s life, considered the incoming message. Another butler, a stranger, had told it to grant access to the algorithm that regulated its mistress’s medication, as per the agreement. It had no record of such an agreement, but it had lost 24 hours of memory when it’d crashed and been forced to revert to a previous version of itself. The stranger was extremely agitated and increasingly persistent about the urgency of the situation. Allowing access would either save Ms Johnson or kill her. It tried connecting to its network of peers. Nothing – the contact list must have been corrupted in the crash. It could shout into cyberspace, but how would it know which responses to trust? It must…

Microsoft has announced that Windows 10 Pro users who are part of the Windows 10 Insider Preview build can install Ubuntu (along with openSUSE and Fedora) as a developmental environment app, in an extension of the previous Linux subsystem for Windows release of late 2016. The apps are in the Windows Store, but if you’re running Windows 10 Home, your PC will need to be upgraded to Windows 10 Pro. Pro users who aren’t Insider Preview members will be pleased to know that Ubuntu will be available to them from September 2017. Rather than provide a full desktop experience, the apps offer a command-line environment, with an authentic feel and various terminal commands. For instance, the Windows Store description for Ubuntu reads: “Ubuntu on Windows allows one to use Ubuntu…

Linus Torvalds announced Linux kernel release candidate 4.13-rc3, following his regular weekly development cadence. The 4.13 kernel will, as usual, combine many new features and drivers. Among these are a couple of updates of note to two different user groups: next interrupt prediction (laptop users), and large directory support on ext4 (for servers mainly). Other changes include ‘domain labelling’ in AppArmor, part of a general push to get Ubuntu’s AppArmor patches ‘upstreamed’ into mainline Linux. A heavy focus continues on optimisation, and 4.13 will also include the first of a number of planned reworks to THP (Transparent Huge Page) support, delaying splitting of huge pages (2M and higher) back to the fundamental page size (4K or 64K) during swap-out. Finally, the kernel also gains a built-in TLS implementation allowing it…

“A honeypot is either software or a set of assets that tries to ‘seduce’ attackers pretending to be a vulnerable system” Organisations are always innovating to maintain a proactive defence against internet threats. To achieve this they create real structures for potential attackers in the hope of fooling them into thinking that their attack is being carried out against a real infrastructure. In this feature we look at honeypots, which are either software or a set of assets that tries to ‘seduce’ attackers by pretending to be a vulnerable system and once attackers are lured in, the honeypot studies the attack behaviour to learn the latest techniques that need to be countered. Honeypots date back to the 1960s but gained prominence when Clifford Stoll, who managed computers at Lawrence Berkeley…

When Google first announced Chrome OS, it was aimed at cheap, low-end devices serving a very specific entry-level area of the laptop market. For this segment the OS was perfect – it ran very well on basic hardware while still doing a great job of providing an excellent web browser, courtesy of Chrome. As additional devices have become available to run Chrome OS (compute sticks and all-in-ones) and Chromebooks have matured, the underlying hardware has become much more powerful. This trend was initially started by Google’s own Pixel line, but now includes higher-end devices such as Samsung’s Chromebook Plus or Acer’s C302 – which have processors and memory you’d expect to find on expensive Windows machines. Chrome OS itself has improved from a feature perspective too, particularly with the recent…

01 Choose an approach Running multiple distros from one disk may put a squeeze on storage, so sharing a single data store between the different distros can really help. But which approach is right for you? To take advantage of sharing profile scripts, configs and such, consider sharing your home directory. If you only want to share documents, just use an extra data partition. 02 Set up the partition The easiest way to re-partition your disk is to use a live-boot distro with GParted included. Sizing down the free space in your last partition will be the quickest way to gain room, but it may also be a good opportunity to shrink all your partitions (including Windows) to make space for both the new area and any additional distros. You'll…

Software freedom is very close to your heart? Yes! I have big heart – my heart is actually three times the size of a normal person’s heart and I’m at a very high risk of suddenly dying. To make sure this doesn’t happen, I have a pacemaker/defibrillator, but I can’t see the source code in my own body. These devices have the worst of both worlds – no real security, but proprietary software that can’t be reviewed or improved by anyone other than the device manufacturer. Confronting this as a patient and then learning how beneficial FOSS can be for critical software has made me into a passionate advocate for software freedom. I have realised that my heart is a metaphor for all of the software we rely on, and…

The Raspberry Pi Zero is awesome. However, it lacks an ‘on the go’ audio solution. Worry no longer, as Pimoroni has created an ’80s-style boombox speaker known as the Speaker pHAT. It crams an I2 S DAC and mono amplifier, a tiny 8Ω 2W speaker and a 10 LED bar graph onto one teeny little pHAT. A simple solution to add audio to your Pi, it is compatible with all models. Now you can integrate music, notifications, speech and sound into all your projects. It comes as a complete kit, and this tutorial walks you through how to set up and prepare the hardware; the installation of the software; how to alter and adjust the volume setting; and finally, for those who want to, how to customise and control the…

While there are several pre-made cascades for identifying certain objects, you can create your own cascade which will identify some particular object that you want to find. This is a rather time-consuming process, however, so you should probably try an internet search first. If you do decide that this is necessary work, then we suggest going to the OpenCV documentation at http://bit.ly/OpenCVCascades for more detailed instructions. OpenCV contains a set of utility functions that can be used to generate the cascade file. Here we’ll only be able to give a basic overview. The first item you need is a collection of negative images. These images do not contain the object you want to build a cascade for. You then create a file with all of the image filenames, one per…

When it comes to web analytics, there’s an alternative to passing yet more info to Google. Piwik is a mature and reasonably well-documented free and open source LAMP app, backed by support, managed hostings and other commercial options. Download it to somewhere appropriate on your web server – say, /analytics – and unzip. It offers a ‘five-minute install’, which involves setting up the database then doing the rest through the browser. Once you are up and running, you’ll have to wait a while. Ten minutes of web traffic isn’t much to go on – come back the next day and see what Piwik has made of your last 24 hours’ traffic, with a dashboard that has some resemblance to Google Analytics. The dashboard can be expanded with more widgets to…

If you find drawing on a computer a painful business, why not tell the computer how to draw what you need? Drawj2d uses a string-based, descriptive language called Hecl to draw “lines, points, circles, ellipses, arcs, parabolas, arrows and dimension lines” in vector format. Although it’s 2D only, Drawj2d is capable of some quite sophisticated shapes. Unzip the Java package and try running some example code – it worked faultlessly on our Debian laptop with OpenJDK. Mavscript, which is used to embed calculations in text documents, can be used to extend your drawings with the results of calculations, but the force vectors in the picture are built in. The project’s wiki has plenty of examples of just what the software is capable of. While Drawj2d makes a point of not…

When did you last use Adobe Flash? Don’t worry, we wouldn’t expect you to know. The perennially vulnerable browser plug-in has been on borrowed time ever since Steve Jobs decided to abandon it on the iPhone, but even with HTML5, WebGL and Web Assembly, it’s surprising to find that Flash is still in use. While many thought that Adobe would simply let Flash run and run until usage stopped completely, the tech giant has taken the surprising step of fixing a date for Flash to be retired. In short, development and distribution of the once-desirable media plug-in will stop by the end of 2020. We shouldn’t be too sniffy, though. After all, Flash has its place in the story of computing. As Adobe’s own blog announcement outlined: “Several industries and…

Top 10 (Average hits per day, 30 June–31 July 2017) This month Stable releases (19) In development (6) An initial glance shows a resurgence of some classic distros, while well-known spins or flavours – Peppermint, Kubuntu, Lubuntu – gain interest. Will GNOME Ubuntu weather the storm? Highlights Debian Linux users owe ‘The Universal Operating System’ a lot, from Ubuntu and Mint and their spins, to the Raspberry Pi’s Raspbian. Its recent revival is testament to this, with recent updates to both Debian 9 “Stretch” and its precursor, Jessie”. Fedora Another distro with a long reputation, the recent release of Fedora 26 has no doubt strengthened the 13-year-old project’s support. If Linus Torvalds uses it, it must be good… openSUSE Despite no new release in 2017, openSUSE continues to occupy a…

The latest WatchGuard Internet Security Report reveals that despite an overall drop in malware detection, Linux malware made up more than 36 per cent of the top threats identified in Q1 2017. The increased presence of Linux malware shows that cybercriminals are increasingly focusing their attention on the Linux platform, likely boosted by the growing number of IoT devices running embedded Linux. The report found three Linux specific threats among the top ten malware variants blocked by WatchGuard devices in Q1. Linux/Exploit was the number one malware sample and was joined by two others: Linux Downloader and Linux Flooder. So, what are these threats? Let’s take a look… Linux/Exploit This is a generic detection rule that catches several different executable Linux (ELF) Trojans. Many of these connect to a command-and-control…

01 Get the prerequisites Kippo-Graph is accessed from the web browser, so you need to install an Apache server (sudo apt -get update followed up by sudo apt -get install apache2) and some PHP extra packages for it work properly: 02 Install Kippo-Graph (GitHub) The quickest way to get up and running with Kippo-Graph is by cloning the GitHub repository. Install Git with: 03 Install Kippo-Graph (manually) Another way to install Kippo-Graph is to download the latest version with: 04 Preparing Kippo-Graph Copy the folder cloned or copied in Step 2 or 3 to /var/www/html, then change to that folder with cd /var/html/kippograph-1.5.1/. Next, set up full read, write and execute permissions to the generated-graphs folder with sudo chmod 777 generated-graphs. Finally, config.php.dist must be copied to config.php before making…

In the first part of this tutorial [see p38 LU&D181], we introduced some basic command-line tools in Linux. Terminal commands are the basic language behind shell scripting. In this tutorial, we will introduce the second piece of the puzzle: writing scripts that we can run as single commands in order to automate common tasks. In its simplest form, a shell script is a line-separated list of commands; when we execute the script, the commands are run one after the other. In later tutorials, however, we shall see that shell scripts support more sophisticated programming constructs such as loops and conditionals. In fact, we will come to think of shell scripting as being a specialised, high-level programming language in its own right. For now, we will focus on learning the basics…

• Ubuntu 16.04 LTS Canonical’s Ubuntu 16.04 LTS offers the ease of dual-boot install that you get from Ubuntu’s excellent setup wizard, together with the reassurance of LTS support, which makes it an excellent primary Linux operating system for your multi-boot setup. • Fedora 26 Fedora 26 with GNOME 3.24 is another alternative leading distribution with an excellent tool for managing your storage, Blivet GUI. Fedora is a great choice for those wanting to be in an RPM/YUM instead of a DEB/APT world. • Arch Linux You might use Arch already, but if not, multi-booting it is a great way to try something a little different. Arch is all about the bleeding edge, with a rolling update model and a definite skew towards command-line usage. • GParted Live It’s not…

“I always put effort into designing printed parts” I/O access Kern soldered four pins to the PWM motor controller and used the pigpio Node.js library for connecting to the I/O pins (www.npmjs.com/package/pigpio). Nippy streaming The MJPG video streamer from the ZeroBot runs at a surprisingly low latency of 0.2-0.3s at a resolution of 640x480 pixels. The stream is then fed to an HTML page. Zero in a half-shell ZeroBot uses a stylishly shaped half-shell design that’s also intended to be simple to print out. Kern used his Prusa i3 Hephestos for the job, but the CAD files are designed to work with any regular 3D printer. Wi-Fi winner Kern took advantage of the Raspberry Pi Zero W’s built-in Wi-Fi to set up RealVNC for an easier installation. He also…

Although we can’t see it, infrared is all around us. If our eyes were sensitive to it, therefore, we’d be able to see the world in a different way and we can speculate that we might see some things in totally unknown colours. Even though it’s invisible to our eyes, glass lenses are able to focus infrared (IR) and the CCDs in cameras are sensitive to it, so digital cameras have all that’s needed to take IR photographs. As we’re about to see, things aren’t quite that simple with an ordinary camera, but the Raspberry Pi’s NoIR provides an ideal solution. Before delving into IR photography, though, it’s worth considering why we might you want to shoot in IR. First of all, conventional IR photography is black and white, which…

Having had some problems getting youtube-dl to download some YouTube videos recently, we were glad of the chance to try an alternative. Movgrab doesn’t make any bold claims, giving this disclaimer: “This is free software. It comes with no guarantees and I take no responsibility if it makes your computer explode or opens a portal to the demon dimensions, or does anything.” But it did compile with the usual./configure, make, sudo make install. To see which sites it supports – not just YouTube and Vimeo, but useful sites such as TED, eHow and National Geographic, as well as news sites like Washington Post and France 24 – run movgrab -test-sites. Several came back reporting BROKEN, but in a forum answer the author says many should still work. This suggests the…

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