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LWN.net is a comprehensive source of news and opinions from and about the Linux community. This is the main LWN.net feed, listing all articles which are posted to the site front page.
Updated: 2 hours 10 min ago

[$] CAP_PERFMON — and new capabilities in general

Friday 21st of February 2020 05:37:58 PM
The perf_event_open() system call is a complicated beast, requiring a fair amount of study to master. This call also has some interesting security implications: it can be used to obtain a lot of information about the running system, and the complexity of the underlying implementation has made it more than usually prone to unpleasant bugs. In current kernels, the security controls around perf_event_open() are simple, though: if you have the CAP_SYS_ADMIN capability, perf_event_open() is available to you (though the system administrator can make it available without any privilege at all). Some current work to create a new capability for the perf events subsystem would seem to make sense, raising the question of why adding new capabilities isn't done more often.

Security updates for Friday

Friday 21st of February 2020 02:03:03 PM
Security updates have been issued by CentOS (openjpeg2), Debian (cloud-init, jackson-databind, and python-reportlab), Red Hat (ksh, python-pillow, systemd, and thunderbird), Slackware (proftpd), SUSE (java-1_7_0-ibm, nodejs10, and nodejs12), and Ubuntu (ppp and squid, squid3).

[$] Memory-management optimization with DAMON

Thursday 20th of February 2020 03:09:52 PM
To a great extent, memory management is based on making predictions: which pages of memory will a given process need in the near future? Unfortunately, it turns out that predictions are hard, especially when they are about future events. In the absence of useful information sent back from the future, memory-management subsystems are forced to rely on observations of recent behavior and an assumption that said behavior is likely to continue. The kernel's memory-management decisions are opaque to user space, though, and often result in less-than-optimal performance. A pair of patch sets from SeongJae Park tries to make memory-usage patterns visible to user space, and to let user space change memory-management decisions in response.

Security updates for Thursday

Thursday 20th of February 2020 02:13:45 PM
Security updates have been issued by Debian (netty and netty-3.9), Fedora (ceph, dovecot, poppler, and webkit2gtk3), openSUSE (inn and rmt-server), Oracle (openjpeg2), Red Hat (rabbitmq-server), Scientific Linux (openjpeg2), SUSE (dnsmasq, rsyslog, and slurm), and Ubuntu (php7.0).

[$] LWN.net Weekly Edition for February 20, 2020

Thursday 20th of February 2020 01:04:41 AM
The LWN.net Weekly Edition for February 20, 2020 is available.

Stable kernel updates

Wednesday 19th of February 2020 09:07:26 PM
Stable kernels 5.5.5, 5.4.21, and 4.19.105 have been released, with the usual set of important fixes.

[$] Debian discusses how to handle 2038

Wednesday 19th of February 2020 07:38:15 PM
At this point, most of the kernel work to avoid the year-2038 apocalypse has been completed. Said apocalypse could occur when time counted in seconds since 1970 overflows a 32-bit signed value (i.e. time_t). Work in the GNU C Library (glibc) and other C libraries is well underway as well. But the "fun" is just beginning for distributions, especially those that support 32-bit architectures, as a recent Debian discussion reveals. One of the questions is: how much effort should be made to support 32-bit architectures as they fade from use and 2038 draws nearer?

The Linux Foundation and Harvard’s Lab for Innovation Science release census for open-source software security

Wednesday 19th of February 2020 07:35:25 PM
The Linux Foundation's Core Infrastructure Initiative and Harvard University's Lab for Innovation Science have teamed up on a census of the most critical open-source components in today's production applications. The report [PDF], titled "Vulnerabilities in the core", identified more than 200 projects and details 20 of them. More information can be found in the press release and, of course, the report. "This Census II analysis and report represent important steps towards understanding and addressing structural and security complexities in the modern day supply chain where open source is pervasive, but not always understood. Census II identifies the most commonly used free and open source software (FOSS) components in production applications and begins to examine them for potential vulnerabilities, which can inform actions to sustain the long-term security and health of FOSS. Census I (2015) identified which software packages in the Debian Linux distribution were the most critical to the kernel’s operation and security."

Security updates for Wednesday

Wednesday 19th of February 2020 03:43:16 PM
Security updates have been issued by CentOS (firefox, java-1.7.0-openjdk, ksh, and sudo), Debian (php7.0 and python-django), Fedora (cacti, cacti-spine, mbedtls, and thunderbird), openSUSE (chromium, re2), Oracle (firefox, java-1.7.0-openjdk, and sudo), Red Hat (openjpeg2 and sudo), Scientific Linux (java-1.7.0-openjdk and sudo), SUSE (dbus-1, dpdk, enigmail, fontforge, gcc9, ImageMagick, ipmitool, php72, sudo, and wicked), and Ubuntu (clamav, linux, linux-aws, linux-aws-hwe, linux-azure, linux-gcp, linux-gke-4.15, linux-hwe, linux-kvm, linux-oracle, linux-raspi2, linux-snapdragon, linux, linux-aws, linux-kvm, linux-raspi2, linux-snapdragon, linux-aws-5.0, linux-azure, linux-gcp, linux-gke-5.0, linux-oracle-5.0, linux-azure, linux-kvm, linux-oracle, linux-raspi2, linux-raspi2-5.3, linux-lts-xenial, linux-aws, and qemu).

[$] Finer-grained kernel address-space layout randomization

Wednesday 19th of February 2020 01:45:55 PM
The idea behind kernel address-space layout randomization (KASLR) is to make it harder for attackers to find code and data of interest to use in their attacks by loading the kernel at a random location. But a single random offset is used for the placement of the kernel text, which presents a weakness: if the offset can be determined for anything within the kernel, the addresses of other parts of the kernel are readily calculable. A new "finer-grained" KASLR patch set seeks to remedy that weakness for the text section of the kernel by randomly reordering the functions within the kernel code at boot time.

Cook: security things in Linux v5.4

Wednesday 19th of February 2020 02:20:21 AM
A bit belatedly, Kees Cook looks at some security-relevant changes in Linux 5.4 in a blog post. He lists a small handful of changes, including: "After something on the order of 8 years, Linux can now draw a bright line between 'ring 0' (kernel memory) and 'uid 0' (highest privilege level in userspace). The 'kernel lockdown' feature, which has been an out-of-tree patch series in most Linux distros for almost as many years, attempts to enumerate all the intentional ways (i.e. interfaces not flaws) userspace might be able to read or modify kernel memory (or execute in kernel space), and disable them. While Matthew Garrett made the internal details fine-grained controllable, the basic lockdown LSM can be set to either disabled, 'integrity' (kernel memory can be read but not written), or 'confidentiality' (no kernel memory reads or writes). Beyond closing the many holes between userspace and the kernel, if new interfaces are added to the kernel that might violate kernel integrity or confidentiality, now there is a place to put the access control to make everyone happy and there doesn’t need to be a rehashing of the age old fight between 'but root has full kernel access' vs 'not in some system configurations'."

Security updates for Tuesday

Tuesday 18th of February 2020 03:50:59 PM
Security updates have been issued by Arch Linux (systemd and thunderbird), Debian (clamav, libgd2, php7.3, spamassassin, and webkit2gtk), Fedora (kernel, kernel-headers, and sway), Mageia (firefox, kernel-linus, mutt, python-pillow, sphinx, thunderbird, and webkit2), openSUSE (firefox, nextcloud, and thunderbird), Oracle (firefox and ksh), Red Hat (curl, java-1.7.0-openjdk, kernel, and ruby), Scientific Linux (firefox and ksh), SUSE (sudo and xen), and Ubuntu (clamav, php5, php7.0, php7.2, php7.3, postgresql-10, postgresql-11, and webkit2gtk).

[$] Filesystem UID mapping for user namespaces: yet another shiftfs

Monday 17th of February 2020 07:35:46 PM
The idea of an ID-shifting virtual filesystem that would remap user and group IDs before passing requests through to an underlying real filesystem has been around for a few years but has never made it into the mainline. Implementations have taken the form of shiftfs and shifting bind mounts. Now there is yet another approach to the problem under consideration; this one involves a theoretically simpler approach that makes almost no changes to the kernel's filesystem layer at all.

Security updates for Monday

Monday 17th of February 2020 03:59:02 PM
Security updates have been issued by Debian (evince, postgresql-9.4, and thunderbird), Fedora (ksh and libxml2), openSUSE (hostapd and nextcloud), Red Hat (chromium-browser, firefox, flash-plugin, and ksh), and SUSE (firefox and thunderbird).

NetBSD 9.0 released

Monday 17th of February 2020 10:03:57 AM
The NetBSD 9.0 release is out. "This is the seventeenth major release of the NetBSD operating system and brings significant improvements in terms of hardware support, quality assurance, security, along with new features and hundreds of bug fixes." Significant new features include Arm64 support, better virtualization support, kernel address-space layout randomization, and more; see the release notes for details.

Kernel prepatch 5.6-rc2

Monday 17th of February 2020 08:59:24 AM
The 5.6-rc2 kernel prepatch is out for testing. Linus says: "More than half the rc2 patch is actually Documentation updates, because the kvm docs got turned into RST. Another notable chunk is just tooling updates, which is about 50/50 perf updates (much of it due to header file syncing) and - again - kvm".

OpenSSH 8.2 released

Saturday 15th of February 2020 09:21:46 AM
OpenSSH 8.2 is out. This release removes support for the ssh-rsa key algorithm, which may disrupt connectivity to older servers; see the announcement for a way to check whether a given server can handle newer, more secure algorithms. Also new in this release is support for FIDO/U2F hardware tokens.

A set of weekend stable kernel updates

Saturday 15th of February 2020 09:15:29 AM
The 5.5.4, 5.4.20, 4.19.104, 4.14.171, 4.9.214, and 4.4.214 stable kernels have all been released; each contains a relatively large set of important fixes.

[$] Keeping secrets in memfd areas

Friday 14th of February 2020 03:03:18 PM
Back in November 2019, Mike Rapoport made the case that there is too much address-space sharing in Linux systems. This sharing can be convenient and good for performance, but in an era of advanced attacks and hardware vulnerabilities it also facilitates security problems. At that time, he proposed a number of possible changes in general terms; he has now come back with a patch implementing a couple of address-space isolation options for the memfd mechanism. This work demonstrates the sort of features we may be seeing, but some of the hard work has been left for the future.

Security updates for Friday

Friday 14th of February 2020 02:37:22 PM
Security updates have been issued by Debian (debian-security-support, postgresql-11, and postgresql-9.6), Fedora (cutter-re, firefox, php-horde-Horde-Data, radare2, and texlive-base), openSUSE (docker-runc), Oracle (kernel), Red Hat (sudo), and Ubuntu (firefox).

More in Tux Machines

Today in Techrights

Planet Changes and Cilium

  • Planet Arch Linux migration

    The software behind planet.archlinux.org was implemented in Python 2 and is no longer maintained upstream. This functionality has now been implemented in archlinux.org's archweb backend which is actively maintained but offers a slightly different experience.

  • Cilium drops 1.7 release, upping insight and manageability

    Network and API connectivity project Cilium has been released in version 1.7, providing users with a UI for observability platform Hubble and the option to apply cluster-wide network policies. Cilium is an open source project developed by US startup Isovalent to provide and secure network connectivity and load balancing for workloads such as application containers or processes. It is based on a virtual machine-like construct called Berkeley Packet Filter (BPF) which can be found in the Linux kernel.

OSS and Development

  • Someone is selling the free, open source Playnite launcher on Steam for $100

    Playnite is a free open source PC application designed to be an all-in-one answer to the growing number of game launchers we've all got on our desktops. In other words, it combines libraries from the likes of Steam, Epic Games Store, Uplay and GOG Galaxy, and then lets you organise them however you see fit. Jody tried it last year and came away impressed. I should emphasise the "free" above: it is available straight from the source here and, according to the site, "no features are locked behind a paywall and the complete source code is available under the MIT license". The MIT license basically surrenders the software to any kind of use with no restrictions, including resales.

  • uGet is an open source download manager for Windows and Linux that also supports Torrents and Video downloads

    The GUI has four panes, a menu bar and a toolbar. The Status pane in the top left corner displays all downloads and the ones which are Active, Queuing, Finished, and Recycled (deleted). The total number of downloads for each category is displayed next to its name, and you can click on any of these to see the list of items contained. Switch to the Category pane to jump between the default and the ones you have created. You can use the Category menu to add new sorting options, set the default download folder for each category, maximum active downloads, and also the maximum upload and download speeds. The pane below the toolbar is the download list pane; anything that you select in the status pane is displayed here. It shows the name, the file size of the download that has been completed, the total size, the progression percentage, time left to complete the download, and the upload/download speeds of each file. The View menu can be used to customize the columns that are displayed in the list pane, and the other visual elements of the program. Highlighting an item in the download list brings up its summary on the bottom pane.

  • Open Source Music Tagger Picard 2.3 Released With Custom MP4 Tags Support

    Free and Open source MusicBrainz announced the point release of Picard 2.3 with major changes to the user interface, tag, and desktop integration support. MusicBrainz stores all the metadata of the music and Picard is the official tag editor that helps in identifying and organizing the digital audio recording.

  • For Square Crypto, the Way to Bitcoin Mass Adoption Is Open Source

    When Jack Dorsey founded Square in February 2009, Bitcoin was all of one month old. In fact, Satoshi Nakamoto and Dorsey were likely laying the groundwork for their respective creations concurrently in the year prior. Ten years later, the two would converge in what now seems like an inevitable collision. Square launched its Venmo-like payment service, Cash App, in 2013. The application features common stock investing, and i

  • Gold-nuggeting: Machine learning tool simplifies target discovery for pen testers

    Recognizing this analogy with the precious metals industry, researchers at Delve Labs have developed Batea, an open source tool that leverages machine learning to find valuable information in network device data.

  • ’Second Revolution’ In Electronic Bond Trading

    Sri Ambati, chief executive and founder at H2O.ai, told Markets Media that the firm’s open source platform can perform one billion regressions in less than five seconds.

  • Google ‘AutoFlip’ can resize video using AI

    The way we consume video has changed a lot over the course of the last decade. We now watch videos on our mobile devices from anywhere and because of this, video content comes in a wide variety of formats. Google recognizes this shift and so last week their AI team announced ‘AutoFlip’ an open-source framework for “intelligent video reframing.”

  • This open-source framework, ‘AutoFlip’, can do automated video cropping using AI

    Many times when we see a video on mobile devices is badly cropped, it is not much you can do about it. Understanding this problem, Google’s AI’s team has built an open-source solution on top of MediaPipe, Autoflip, which can reframe a video that fits any device or dimension (landscape, portrait, etc.). AutoFlip works in three phases. The first phase includes scene detection; the second is the video content analysis, and the third is reframing. For this tool, if a video and a target dimension are given, it analyzes the video content. Later it develops optimal tracking and cropping strategies, which finally enables it to create an output video at the same time limit in the desired aspect ratio.

  • Tech Events in Africa: Nerds Unite, Open Source Festival and #CodeZone

    It’s a new week and another opportunity to meet up with like-minded people, become better in your chosen field and seal those deals for your startup. And we at TechNext want to help with a list of tech events happening around you this week.

  • An unofficial version of Brave browser brings native ARM64 support

    Privacy-focused Brave browser launched late last year after almost four years of being in the works. The browser is based on the Chromium open-source project and joins the likes of Microsoft Edge that is built on that platform. However, while Mozilla Firefox and Microsoft’s offering currently support ARM64 PCs natively in the stable channels, Brave does not. That might change, as Windows Insider MVP Jeremy Sinclair was able to compile an unofficial build of the open-source Brave browser that natively supports ARM64 PCs. The recompiled build (version 1.6.33) uses Microsoft’s ARM64 Chromium libraries and can run natively on those PCs like the Surface Pro X. Samsung Galaxy Book S. Native support results in improved performance and efficiency since the browser will not have to run in emulation.

  • The Brave web browser is taking on Google Chrome: Is it safe?

    The creator of Brave, Brendan Eich, also created JavaScript and co-founded the Mozilla Project that led to the development of the Firefox browser. Brave is based on the open-source Chromium browser that’s also the basis for Google’s Chrome, Opera and most recently Microsoft’s Chromium Edge browser. Open-source means that anyone can take the source code and build whatever they’d like out of it, but it doesn’t mean that all the browsers are the same. In the case of Brave, they chose to focus on user privacy by blocking trackers, scripts and ads by default. The natural by-product of blocking all this activity that usually goes unnoticed by the average user is faster load times. Brave can also make use of the wide variety of extensions for Chromium-based browsers via the Chrome Web Store at chrome.google.com.

  • This new tool could improve economic analysis of sub-national climate policies in the US

    Empowered by the Paris Agreement and a lack of national leadership on climate policy in the United States, state and local governments are leading on their own climate initiatives. California, New York and Colorado have set ambitious greenhouse gas emission and renewable energy targets for 2030. Just last week, Massachusetts introduced sweeping climate legislation targeting net zero emissions by 2050. As these environmental and energy policies move ahead, experts need to invest in economic data and tools that allow them to conduct robust economic analysis, to better inform policymakers, stakeholders and the public on how to design robust alternative climate and energy policies.

  • 2020 Open Access Award Finalists Named

    The Benjamin Franklin Award for Open Access in the Life Sciences is a humanitarian/bioethics award presented annually by Bioinformatics.org to an individual who has, in his or her practice, promoted free and open access to the materials and methods used in the life sciences.

  • Are we having fund yet, npm? CTO calls for patience after devs complain promised donations platform has stalled

    At the end of August, JavaScript package registry NPM Inc said it intended "to finalize and launch an Open Source funding platform by the end of 2019." But instead of a platform, what's available at the moment might be better referred to as a feature of the npm command-line interface (CLI). The announcement was received with some skepticism at the time and the project hasn't managed to defy that expectation: There was a minor milestone last November with the addition of the "fund" command to npm v6.13.0. But not much has changed since then.

  • RcppSimdJson 0.0.2: First Update!

    RcppSimdJson wraps the fantastic simdjson library by Daniel Lemire which truly impressive. Via some very clever algorithmic engineering to obtain largely branch-free code, coupled with modern C++ and newer compiler instructions, it results in persing gigabytes of JSON parsed per second which is quite mindboggling. I highly recommend the video of the recent talk by Daniel Lemire at QCon (which was also voted best talk). The best-case performance is ‘faster than CPU speed’ as use of parallel SIMD instructions and careful branch avoidance can lead to less than one cpu cycle use per byte parsed. This release syncs the simdjson headers with upstream, and polishes the build a little by conditioning on actually having a C++17 compiler rather than just suggesting it. The NEWS entry follows.

  • Nvidia Blames ‘Misunderstanding’ for Activision Faux Pas

    When Nvidia Corp. abruptly dropped Activision Blizzard Inc. games from its new GeForce Now service earlier this week, it left customers wondering what happened. Nvidia said on Tuesday that Activision had asked to have its titles removed from GeForce, but didn’t explain why. It turns out that the video-game giant wanted a commercial agreement with Nvidia before they proceeded -- and the situation stemmed from a simple misunderstanding, Nvidia said on Thursday.

Web Standards

  • Inrupt, Tim Berners-Lee's Solid, and Me

    All of this is a long-winded way of saying that I have joined a company called Inrupt that is working to bring Tim Berners-Lee's distributed data ownership model that is Solid into the mainstream. (I think of Inrupt basically as the Red Hat of Solid.) I joined the Inrupt team last summer as its Chief of Security Architecture, and have been in stealth mode until now.

    The idea behind Solid is both simple and extraordinarily powerful. Your data lives in a pod that is controlled by you. Data generated by your things -- your computer, your phone, your IoT whatever -- is written to your pod. You authorize granular access to that pod to whoever you want for whatever reason you want. Your data is no longer in a bazillion places on the Internet, controlled by you-have-no-idea-who. It's yours. If you want your insurance company to have access to your fitness data, you grant it through your pod. If you want your friends to have access to your vacation photos, you grant it through your pod. If you want your thermostat to share data with your air conditioner, you give both of them access through your pod.

  • World wide web founder scales up efforts to reshape internet
  • Sir Tim Berners-Lee's Inrupt is Redesigning the way the web is to Work and Apple is working with them on their Data Transfer Project

    Inrupt, the start-up company founded by Sir Tim Berners-Lee to redesign the way the web works, is expanding its operational team and launching pilot projects in its quest to develop a "massively scalable, production-quality technology platform."

  • Inconsistent user-experiences with native lazy-loading images

    The specification for web browser native support for lazy-loading images landed in the HTML Living Standard a week ago. This new feature lets web developers tell the browser to defer loading an image until it is scrolled into view, or it’s about to be scrolled into view. Images account for 49 % of the median webpage’s byte size, according to the HTTP Archive. Lazy image loading can help reduce these images’ impact on page load performance. It can also help lower data costs by clients that never scroll down to images far down on a page. Historically, lazy-loading was implemented by responding to changes in the scroll position and tracking the image element’s offset from the top of the page. This could degrade page-scrolling performance. Comparatively, the new native lazy loading for images is easier to implement and doesn’t degrade scrolling performance.