Escalating Privileges In Ubuntu 20.04 From User Account

Ubuntu 20.04 is an incredibly popular operating system, perhaps the most popular among the Linux distributions due to its ease-of-use. In general, it’s a fairly trustworthy operating system too, especially since its source code is open. However, an update with the 20.04 revision has led to security researcher [Kevin Backhouse] finding a surprisingly easy way to escalate privileges on this OS, which we would like to note is not great.

The exploit involves two bugs, one in accountservice daemon which handles user accounts on the computer, and another in the GNOME Display Manager which handles the login screen. Ubuntu 20.04 added some code to the daemon which looks at a specific file on the computer, and with a simple symlink, it can be tricked into reading a different file which locks the process into an infinite loop. The daemon also drops its privileges at one point in this process, a normal security precaution, but this allows the user to crash the daemon.

The second bug for this exploit involves how the GNOME Display Manager (gdm3) handles privileges. Normally it would not have administrator privileges, but if the accountservice daemon isn’t running it escalates itself to administrator, where any changes made have administrator privileges. This provides an attacker with an opportunity to create a new user account with administrator privileges.

Of course, this being Ubuntu, we can assume that this vulnerability will be immediately patched. It’s also a good time to point out that the reason that open-source software is inherently more secure is that when anyone can see the source code, anyone can find and report issues like this which allow the software maintainer (or even the user themselves) to make effective changes more quickly.

Ubuntu (Finally) Officially Lands On The Raspberry Pi. But Will Anyone Notice?

The Raspberry Pi has been with us for over eight years now, and during that time it has seen a myriad operating system ports. It seems that almost anything can be run on the little computer, but generally the offerings have seen minority uptake in the face of the officially supported Raspbian, or as it’s now called, Raspberry Pi OS.

Maybe that could change, with the arrival of an Ubuntu release for the platform. For those of you pointing out that this is nothing new, what makes the new version 20.10 release special is that it’s the first official full Ubuntu release, rather than an unofficial port.

So Raspberry Pi 4 owners can now install the same full-fat Ubuntu they have on their PCs, and with the same official Ubuntu support. What does this really do for them that Raspberry Pi OS doesn’t? Underneath they share Debian underpinnings, and they both benefit from a huge quantity of online resources should the user find themselves in trouble. Their repositories both contain almost every reasonable piece of software that could be imagined, so the average Pi user might be forgiven for a little confusion.

We don’t expect this news to take the Pi desktop world by storm then. Ubuntu is a powerful distribution, but it’s fair to say that it is not the least bloated among distributions, and that some of its quirks such as Snap applications leave many users underwhelmed. By contrast Raspberry Pi OS is relatively lightweight, and crucially it’s optimised for the Pi. Its entire support base online is specific to the Pi hardware, so the seeker of solutions need not worry about encountering some quirk in an explanation that pertains only to PC platforms.

It’s fair to say though, that this release is almost certainly not targeted at the casual desktop user. We’d expect that instead it will be in the Ubuntu portfolio for commercial and enterprise users, and in particular for the new Raspberry Pi 4 Compute Module in which it will no doubt form the underpinnings of many products without their owners ever realising it.

[via OMG Ubuntu]

Ubuntu Update Hack Chat

Join us on Wednesday, July 22 at noon Pacific for the Ubuntu Update Hack Chat with Rhys Davies and Alan Pope!

Everyone has their favorite brands, covering everything from the clothes they wear to the cars they drive. We see brand loyalty informing all sorts of acquisition decisions, not only in regular consumer life but in technology, too. Brand decisions sort people into broad categories like Mac versus PC, or iPhone versus Android, and can result in spirited discussions of the relative merits of one choice over the others. It’s generally well-intentioned, even if it gets a bit personal sometimes.

Perhaps no choice is more personal in hacker circles than which Linux distribution to use. There are tons to choose from, each with their various features and particular pros and cons. Ubuntu has become a very popular choice for Linux aficionados, attracting more than a third of the market. Canonical is the company behind the Debian-based distro, providing editions that run on the desktop, on servers, and on a variety of IoT devices, as well as support and services for large-scale users.

To fill us in on what’s new in the world of Ubuntu, Canonical product manager Rhys Davies and developer advocate Alan Pope will stop by the Hack Chat this week. They’ll be ready to answer all your questions about the interesting stuff that’s going on with Ubuntu, including the recently announced Ubuntu Appliances, easy to install, low maintenance images for Raspberry Pis and PCs that are built for security and simplicity. We’ll also talk about snaps, desktops, and whatever else crops up.

join-hack-chatOur Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, July 22 at 12:00 PM Pacific time. If time zones have you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about. Continue reading “Ubuntu Update Hack Chat”

What’s The Deal With Snap Packages?

Who would have thought that software packaging software would cause such a hubbub? But such is the case with snap. Developed by Canonical as a faster and easier way to get the latest versions of software installed on Ubuntu systems, the software has ended up starting a fiery debate in the larger Linux community. For the more casual user, snap is just a way to get the software they want as quickly as possible. But for users concerned with the ideology of free and open source software, it’s seen a dangerous step towards the types of proprietary “walled gardens” that may have drove them to Linux in the first place.

Perhaps the most vocal opponent of snap, and certainly the one that’s got the most media attention, is Linux Mint. In a June 1st post on the distribution’s official blog, Mint founder Clement Lefebvre made it very clear that the Ubuntu spin-off does not approve of the new package format and wouldn’t include it on base installs. Further, he announced that Mint 20 would actively block users from installing the snap framework through the package manager. It can still be installed manually, but this move is seen as a way to prevent it from being added to the system without the user’s explicit consent.

The short version of Clement’s complaint is that the snap packager installs from a proprietary Canonical-specific source. If you want to distribute snaps, you have to set up an account with Canonical and host it there. While the underlying software is still open source, the snap packager breaks with long tradition of having the distribution of the software also being open and free. This undoubtedly makes the install simple for naive users, and easier to maintain for Canonical maintainers, but it also takes away freedom of choice and diversity of package sources.

Continue reading “What’s The Deal With Snap Packages?”

Double 3: Your Instant Physical Presence Anywhere, No Matter Where You Are

Telepresence is one of those futuristic buzzwords that’s popped up a few times over the decades; promising the ability to attend a meeting in New York City and another in Tokyo an hour later, all without having to leave the comfort of your home or office. This is the premise of Double Robotics’ Double 3, its most recent entry in this market segment, as the commercial counterpoint to more DIY offerings.

More than just a glorified tablet screen.

Looking like a tablet perched on top of a Segway, the built-in dual 13 megapixel cameras allow the controller to get a good look at their surroundings, while the 6 beamforming microphones should theoretically allow one to pick up any conversation in a meeting or on the work floor.

Battery life is limited to 4 hours, and it takes 2 hours to recharge the built-in battery. Fortunately one can just hop over to another, freshly charged Double 3 if the battery runs out. Assuming the $3,999 price tag doesn’t get in the way of building up a fleet of them, anyway.

Probably the most interesting aspect of the product is its self-driving feature, which has resulted in a whole range of sensors and cameras (Intel RealSense D430 stereo vision depth sensors) being installed. To handle the processing of this sensor data, the system is equipped with an NVidia Jetson TX2 ARM board, running Ubuntu Linux, which also renders the mixed-reality UI for the user with way points and other information.

Currently Double Robotics accepts sign-ups for the private beta of the Double 3 API, which would give developers access to the sensor data and various autonomous features of Double 3’s hardware. Co-founder of Double Robotics, [Marc DeVidts] stated to Hackaday that he is looking forward to seeing what people can build with it. Hopefully this time people will not simply take the thing for a joyride, like what happened with a predecessor of the Double 3.

The Saga Of 32-Bit Linux: Why Going 64-Bit Raises Concerns Over Multilib

The story of Linux so far, as short as it may be in the grand scheme of things, is one of constant forward momentum. There’s always another feature to implement, an optimization to make, and of course, another device to support. With developer’s eyes always on the horizon ahead of them, it should come as no surprise to find that support for older hardware or protocols occasionally falls to the wayside. When maintaining antiquated code monopolizes developer time, or even directly conflicts with new code, a difficult decision needs to be made.

Of course, some decisions are easier to make than others. Back in 2012 when Linus Torvalds officially ended kernel support for legacy 386 processors, he famously closed the commit message with “Good riddance.” Maintaining support for such old hardware had been complicating things behind the scenes for years while offering very little practical benefit, so removing all that legacy code was like taking a weight off the developer’s shoulders.

The rationale was the same a few years ago when distributions like Arch Linux decided to drop support for 32-bit hardware entirely. Maintainers had noticed the drop-off in downloads for the 32-bit versions of their distributions and decided it didn’t make sense to keep producing them. In an era where even budget smartphones are shipping with 64-bit processors, many Linux distributions have at this point decided 32-bit CPUs weren’t worth their time.

Given this trend, you’d think Ubuntu announcing last month that they’d no longer be providing 32-bit versions of packages in their repository would hardly be newsworthy. But as it turns out, the threat of ending 32-bit packages caused the sort of uproar that we don’t traditionally see in the Linux community. But why?

Continue reading “The Saga Of 32-Bit Linux: Why Going 64-Bit Raises Concerns Over Multilib”

Making The Case For Slackware In 2018

If you started using GNU/Linux in the last 10 years or so, there’s a very good chance your first distribution was Ubuntu. But despite what you may have heard on some of the elitist Linux message boards and communities out there, there’s nothing wrong with that. The most important thing is simply that you’re using Free and Open Source Software (FOSS). The how and why is less critical, and in the end really boils down to personal preference. If you would rather take the “easy” route, who is anyone else to judge?

Having said that, such options have not always been available. When I first started using Linux full time, the big news was that the kernel was about to get support for USB Mass Storage devices. I don’t mean like a particular Mass Storage device either, I mean the actual concept of it. Before that point, USB on Linux was mainly just used for mice and keyboards. So while I might not be able to claim the same Linux Greybeard status as the folks who installed via floppies on an i386, it’s safe to say I missed the era of “easy” Linux by a wide margin.

But I don’t envy those who made the switch under slightly rosier circumstances. Quite the opposite. I believe my understanding of the core Unix/Linux philosophy is much stronger because I had to “tough it” through the early days. When pursuits such as mastering your init system and compiling a vanilla kernel from source weren’t considered nerdy extravagance but necessary aspects of running a reliable system.

So what should you do if you’re looking for the “classic” Linux experience? Where automatic configuration is a dirty word, and every aspect of your system can be manipulated with nothing more exotic than a text editor? It just so happens there is a distribution of Linux that has largely gone unchanged for the last couple of decades: Slackware. Let’s take a look at its origins, and what I think is a very bright future.

Continue reading “Making The Case For Slackware In 2018”