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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: 1 hour 48 min ago

[$] Implementing fully immutable files

Friday 19th of April 2019 02:57:19 PM
Like all Unix-like systems, Linux implements the traditional protection bits controlling who can access files in a filesystem (and what access they have). Fewer users, perhaps, are aware of a set of additional permission bits hidden away behind the chattr and lsattr commands. Among other things, these bits can make a file append-only, mark a file to be excluded from backups, cause a file's data to be automatically overwritten on deletion, or make a file immutable. The implementation of many of these features is incomplete at best, so perhaps it's not surprising that immutable files can still be changed in certain limited circumstances. Darrick Wong has posted a patch set changing this behavior, implementing a user-visible behavioral change that he describes as "an extraordinary way to destroy everything".

Security updates for Friday

Friday 19th of April 2019 12:45:45 PM
Security updates have been issued by Fedora (atomic-reactor and osbs-client), openSUSE (libqt5-qtbase, lxc, tar, wget, and xmltooling), Scientific Linux (java-1.8.0-openjdk and java-11-openjdk), SUSE (php5), and Ubuntu (znc).

[$] Tracking pages from get_user_pages()

Thursday 18th of April 2019 04:01:49 PM
As has been recently discussed here, developers for the filesystem and memory-management subsystems have been grappling for years with the problems posed by the get_user_pages() mechanism. This function maps memory into the kernel's address space for direct access by the kernel or peripheral devices, but that kind of access can create confusion in the filesystem layers, which may not be expecting that memory to be written to at any given time. A new patch set from Jérôme Glisse tries to chip away at a piece of the problem, but a complete solution is not yet in view.

Ubuntu 19.04 (Disco Dingo) released

Thursday 18th of April 2019 01:34:58 PM
Ubuntu 19.04, code named "Disco Dingo", has been released, along with the following flavors: Ubuntu Budgie, Kubuntu, Lubuntu, Ubuntu Kylin, Ubuntu MATE, Ubuntu Studio, and Xubuntu. "The Ubuntu kernel has been updated to the 5.0 based Linux kernel, our default toolchain has moved to gcc 8.3 with glibc 2.29, and we've also updated to openssl 1.1.1b and gnutls 3.6.5 with TLS1.3 support. Ubuntu Desktop 19.04 introduces GNOME 3.32 with increased performance, smoother startup animations, quicker icon load times and reduced CPU+GPU load. Fractional scaling for HiDPI screens is now available in Xorg and Wayland. Ubuntu Server 19.04 integrates recent innovations from key open infrastructure projects like OpenStack Stein, Kubernetes, and Ceph with advanced life-cycle management for multi-cloud and on-prem operations, from bare metal, VMware and OpenStack to every major public cloud." More information can be found in the release notes.

OpenSSH 8.0 released

Thursday 18th of April 2019 01:11:27 PM
OpenSSH 8.0 has been released with a bunch of new features and some bug fixes, including one for a security problem: "This release contains mitigation for a weakness in the scp(1) tool and protocol (CVE-2019-6111): when copying files from a remote system to a local directory, scp(1) did not verify that the filenames that the server sent matched those requested by the client. This could allow a hostile server to create or clobber unexpected local files with attacker-controlled content. This release adds client-side checking that the filenames sent from the server match the command-line request, The scp protocol is outdated, inflexible and not readily fixed. We recommend the use of more modern protocols like sftp and rsync for file transfer instead."

Security updates for Thursday

Thursday 18th of April 2019 12:58:58 PM
Security updates have been issued by CentOS (polkit), Gentoo (dovecot, libseccomp, and patch), openSUSE (aubio, blktrace, flac, lxc, lxcfs, pspp, SDL, sqlite3, and xen), Red Hat (java-1.8.0-openjdk, java-11-openjdk, and rh-maven35-jackson-databind), Scientific Linux (java-1.8.0-openjdk), Slackware (libpng), SUSE (python, python3, sqlite3, and xerces-c), and Ubuntu (ntfs-3g).

[$] LWN.net Weekly Edition for April 18, 2019

Thursday 18th of April 2019 01:09:43 AM
The LWN.net Weekly Edition for April 18, 2019 is available.

[$] Business models and open source

Wednesday 17th of April 2019 07:02:09 PM

One of the more lively sessions that was held at the 2019 Legal and Licensing Workshop (LLW) was Heather Meeker's talk on open-source business models and alternative licensing. As a lawyer in private practice, Meeker worked on a number of the alternative licenses that were drafted and presented over the last year or so. But she is also part of a venture capital (VC) firm that is exclusively investing in companies focused on open source, so she has experience in thinking about what kinds of models actually work for those types of businesses.

Stable kernel updates

Wednesday 17th of April 2019 02:38:02 PM
Stable kernels 5.0.8, 4.19.35, 4.14.112, and 4.9.169 have been released. They all contain important fixes and users should upgrade.

Security updates for Wednesday

Wednesday 17th of April 2019 02:31:53 PM
Security updates have been issued by CentOS (mod_auth_mellon), Debian (ghostscript and ruby2.3), openSUSE (dovecot22, gnuplot, and openwsman), Scientific Linux (mod_auth_mellon), SUSE (krb5, openexr, python3, and wget), and Ubuntu (firefox and openjdk-lts).

[$] An update on compliance for containers

Tuesday 16th of April 2019 08:07:57 PM

The inability to determine the contents of container images is a topic that annoys Dirk Hohndel. At last year's Legal and Licensing Workshop (LLW), he gave a presentation that highlighted the problem and some work he had been doing to combat it. At this year's LLW, he updated attendees on the progress that has been made and where he hopes things will go from here.

Security updates for Tuesday

Tuesday 16th of April 2019 02:53:33 PM
Security updates have been issued by Debian (cacti and libxslt), Fedora (pcsc-lite and samba), Gentoo (gnutls, phpmyadmin, and tiff), openSUSE (apache2, clamav, dovecot23, nodejs10, SDL, and webkit2gtk3), Red Hat (mod_auth_mellon and rh-python36-python), SUSE (firefox, nspr, nss and python), and Ubuntu (libxslt and webkit2gtk).

[$] Avoiding page reference-count overflows

Tuesday 16th of April 2019 12:49:34 AM
The 5.1-rc5 announcement mentioned "changes all over" and highlighted a number of the areas that had been touched. One thing that was not mentioned there was the addition of four patches fixing a security-related issue in the core memory-management subsystem. The vulnerability is sufficiently difficult to exploit that almost nobody should feel the need to rush out a kernel update, but it is still interesting to look at as a demonstration of how things can go wrong.

An eBPF overview series from Collabora

Monday 15th of April 2019 08:38:32 PM
Adrian Ratiu is posting a series of articles on the Collabora blog digging into the kernel's eBPF subsystem. The first two parts are available now: an introduction and a look at the virtual machine. "eBPF is a RISC register machine with a total of 11 64-bit registers, a program counter and a 512 byte fixed-size stack. 9 registers are general purpouse read-write, one is a read-only stack pointer and the program counter is implicit, i.e. we can only jump to a certain offset from it. The VM registers are always 64-bit wide (even when running inside a 32-bit ARM processor kernel!) and support 32-bit subregister addressing if the most significant 32 bits are zeroed - this will be very useful in part 4 when cross-compiling and running eBPF programs on embedded devices."

Stable kernel updates

Monday 15th of April 2019 07:10:44 PM
Stable kernels 5.0.7, 4.19.34, 4.14.111, and 4.9.168 were actually released last week, but the email wasn't sent. As usual they all contain important fixes and users should upgrade.

Security updates for Monday

Monday 15th of April 2019 03:02:13 PM
Security updates have been issued by Debian (graphicsmagick, jasper, and libssh2), Fedora (kernel, kernel-headers, kernel-tools, nodejs-simple-markdown, and php), openSUSE (netpbm and xen), and SUSE (audiofile, firefox, java-1_7_0-openjdk, libvirt, openssh, and systemd).

Kernel prepatch 5.1-rc5

Monday 15th of April 2019 02:02:28 PM
The 5.1-rc5 kernel prepatch is out for testing. "Nothing in here makes me feel uncomfortable about this release cycle so far. Knock wood."

[$] Expedited memory reclaim from killed processes

Friday 12th of April 2019 10:26:47 PM
Running out of memory puts a Linux system into a difficult situation; in the worst cases, there is often no way out other than killing one or more processes to reclaim their memory. This killing may be done by the kernel itself or, on systems like Android, by a user-space out-of-memory (OOM) killer process. Killing a process is almost certain to make somebody unhappy; the kernel should at least try to use that process's memory expeditiously so that, with luck, no other processes must die. That does not always happen, though, in current kernels. This patch set from Suren Baghdasaryan aims to improve the situation, but the solution that results in the end may take a different form.

Emacs 26.2 released

Friday 12th of April 2019 07:38:04 PM
Version 26.2 of the Emacs editor is out. The headline features include the ability to build modules outside of the source tree, Unicode 11 compliance, and the long-awaited ability to compress an entire directory full of files with a single keystroke.

Security updates for Friday

Friday 12th of April 2019 03:05:35 PM
Security updates have been issued by CentOS (freerdp, kernel, openssh, and python), Fedora (checkstyle), openSUSE (bluez, file, kernel, and libarchive), SUSE (apache2, curl, ghostscript, libvirt, openssh, and systemd), and Ubuntu (rssh).

More in Tux Machines

Graphics: AMDGPU and X.Org Elections

  • amdgpu drm-next-5.2
  • AMDGPU Has Another Round Of Updates Ahead Of Linux 5.2
    Feature work on DRM-Next for the Linux 5.2 kernel cycle is winding down while today AMD has sent in what could be their last round of AMDGPU feature updates for this next kernel release. Building off their earlier Linux 5.2 feature work are more updates. That earlier round brought new SMU11 enablement code for Vega 20, various other Vega 20 features, HMM preparations, and other code changes.
  • 2019 Election Round 2 voting OPEN
    To all X.Org Foundation Members: The round 2 of X.Org Foundation's annual election is now open and will remain open until 23:59 UTC on 2 May 2019. Four of the eight director seats are open during this election, with the four nominees receiving the highest vote totals serving as directors for two year terms. There were six candidates nominated. For a complete list of the candidates and their personal statements, please visit the 2019 X.Org Elections page at https://www.x.org/wiki/BoardOfDirectors/Elections/2019/ The new bylaw changes were approved in the first round of voting. Here are some instructions on how to cast your vote: Login to the membership system at: https://members.x.org/ If you do not remember your password, you can click on the "lost password" button and enter your user name. An e-mail will be sent to you with your password. If you have problems with the membership system, please e-mail membership at x.org. When you login you will see an "Active Ballots" section with the "X.Org 2019 Elections Round 2" ballot. When you click on that you will be presented with a page describing the ballot. At the bottom you will find a number of dropdowns that let you rank your candidates by order of preference. For the election: There is a pull-down selection box for 1st choice, 2nd, choice, and so on. Pick your candidates top to bottom in order of preference, avoiding duplicates. After you have completed your ballot, click the "Cast vote" button. Note that once you click this button, your votes will be cast and you will not be able to make further changes, so please make sure you are satisfied with your votes before clicking the "Cast vote" button. After you click the "Vote" button, the system will verify that you have completed a valid ballot. If your ballot is invalid (e.g., you duplicated a selection or did not answer the By-laws approval question), it will return you to the previous voting page. If your ballot is valid, your votes will be recorded and the system will show you a notice that your votes were cast. Note that the election will close at 23:59 UTC on 2 May 2019. At that time, the election committee will count the votes and present the results to the current board for validation. After the current board validates the results, the election committee will present the results to the Members. Harry, on behalf of the X.Org elections committee
  • It's Time To Re-Vote Following The Botched 2019 X.Org Elections
    While there were the recent X.Org Foundation board elections, a do-over was needed as their new custom-written voting software wasn't properly recording votes... So here's now your reminder to re-vote in these X.Org elections. At least with the initial round of voting they reached a super majority and the ballot question of whether the X.Org Foundation should formally fold FreeDesktop.org into its umbrella worked and that X.Org + FreeDesktop.org hook-up passed so all is well on that front. But for the Board of Directors elections, that's where re-voting is needed with the voting software that now correctly records the votes.

today's howtos

Games: Lutris and More

  • Epic Games Store Now On Linux Thanks To Lutris
    While the Epic Games Store itself is not officially supported by the open source Linux operating system, a third-party gaming client has now made sure that you can access the store and launcher on your own distro. The Epic Games Store is now accessible on Linux via the Lutris Gaming client. The client is available to all Linux users, who in the past has provided the same users a way to play PC games without the need to have Windows installed in their machines. Although Linux is not necessarily the go-to platform when it comes to PC gaming, there is a very niche audience dedicated to making the platform work in favor of open-source and to counteract what could be perceived as a heavily Windows-biased PC gaming community. Linux gaming is somewhat tedious to the relatively casual or normal user, although there are some within the Linux community that advertise and try to foster its growth in terms of gaming, as there are some games that can run better on the operating system. That is to say, if you have a lot of patience to try and make it work.
  • You Died but a Necromancer revived you is good fun in a small package
    Sometimes, simplicity is what makes a game and in the case of You Died BaNRY that's very true. The game has little depth to it but makes up for that in just how frantic and fun it can be. The entire gameplay is just you (or you and friends) attempting to cross a small level filled with platforms, spikes and all sorts of crazy traps. It's ridiculously easy to get into as well, since the controls are so basic all you need to worry about is your movement.
  • Forager is a weirdly addictive casual grinding game that has mined into my heart
    I'm not usually one for games that have you endlessly wander around, collect resources, build a little and repeat but Forager is so ridiculously charming it's lovely.
  • DragonRuby Game Toolkit, a cross-platform way to make games with Ruby
    Now for something a little different! Ryan "Icculus" Gordon, a name known for many Linux ports and SDL2 teamed up with indie developer Amir Rajan to create a new cross-platform toolkit. Why was it created? Well, in a nutshell they both "hate the complexity of today's engines" and this toolkit was actually made to help ship A Dark Room for the Nintendo Switch, which shows how versatile it is.

10+ Open Source Software Writing Tools That Every Writer Should Know

Being a professional writer requires two key things to help ensure success: commitment and support. The former comes from the writer, and the latter comes from the tools he (or she) uses to get the job done. Below is a list of 11 great and lesser-known writing tools or apps, many of which are free and open-source, that can help improve the quality of your writing and make you a more productive and successful writer. Read more