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The MythTV Team has announced the release of MythTV 30.0. The release notes contain more information. This version includes support for mythfrontend running on certain Android TV devices. "Over 500 commits made significant improvements to the infrastructure. For the most part, these are invisible to end users."

Security updates have been issued by Debian (mxml, postgresql-9.4, and tmpreaper), Fedora (haproxy and runc), openSUSE (krb5, soundtouch, virtualbox, and zeromq), Oracle (thunderbird), Red Hat (thunderbird), and Ubuntu (subversion and thunderbird).

Rory Aronson started his 2019 linux.conf.au keynote with a statement that gardening just isn't his passion; an early attempt degenerated into a weed-choked mess when he couldn't be bothered to keep it up. But he turned out to be passionate indeed about building a machine that would do the gardening for him. That led to the FarmBot project, a successful exercise in the creation of open hardware, open software, and an open business. A big part of that success, it turns out, lies in the project's documentation.

The Debian Project has announced an update to Debian 9 "stretch". "This point release incorporates the recent security update for APT, in order to help ensure that new installations of stretch are not vulnerable. No other updates are included."

Security updates have been issued by CentOS (perl), Fedora (anaconda, curl, and poppler), openSUSE (ntpsec), SUSE (ghostscript, kernel, rubygem-activejob-4_2, and webkit2gtk3), and Ubuntu (ghostscript and mysql-5.7).

The LWN.net Weekly Edition for January 24, 2019 is available.

Here is an extensive look at handling software dependencies from Russ Cox. "Dependency managers have scaled this open-source code reuse model down: now, developers can share code at the granularity of individual functions of tens of lines. This is a major technical accomplishment. There are myriad available packages, and writing code can involve such a large number of them, but the commercial, legal, and reputational support mechanisms for trusting the code have not carried over. We are trusting more code with less justification for doing so."

A flag day for DNS is coming on February 1; it may have escaped notice even though it has been planned for nearly a year. Some DNS servers will simply be marked as "dead" by much of the rest of the internet on or after that day, which means that domain owners need to ensure their DNS records will still be available after that point. A longstanding workaround for non-compliant servers will be dropped—mostly for better performance but also in support of DNS extensions, some of which can help alleviate security problems.

Read-copy update (RCU) is a synchronization mechanism that was added to the Linux kernel in October 2002. RCU is most frequently described as a replacement for reader-writer locking, but has also been used in a number of other ways. RCU is notable in that readers do not directly synchronize with updaters, which makes RCU read paths extremely fast; that also permits RCU readers to accomplish useful work even when running concurrently with updaters. Although the basic idea behind RCU has not changed in decades following its introduction into DYNIX/ptx, the API has evolved significantly over the five years since the 2014 edition of the RCU API, to say nothing of the nine years since the 2010 edition of the RCU API.

Max Justicz describes a vulnerability in apt-get and how to prevent it. "I found a vulnerability in apt that allows a network man-in-the-middle (or a malicious package mirror) to execute arbitrary code as root on a machine installing any package. The bug has been fixed in the latest versions of apt. If you’re worried about being exploited during the update process, you can protect yourself by disabling HTTP redirects while you update."

Version 4.0 of the Wine Windows compatibility layer is out. "This release represents a year of development effort and over 6,000 individual changes" New features include initial Direct3D 12 support, a Vulkan graphics driver, support for high-DPI displays (but only on Android) and more; see the release notes for details.

Stable kernels 4.20.4, 4.19.17, 4.14.95, and 4.9.152 have been released. They all contain important fixes and users should upgrade.

Security updates have been issued by Debian (libjpeg-turbo and systemd), Fedora (matrix-synapse, mingw-libjpeg-turbo, and mingw-libvorbis), Mageia (libcaca, libmp4v2, libxml2, pdns-recursor, perl-Email-Address, php-pear-HTML_QuickForm, podofo, and wavpack), openSUSE (webkit2gtk3), Red Hat (qemu-kvm-rhev), Scientific Linux (perl), Slackware (httpd), and Ubuntu (ntp).

Security updates have been issued by Debian (apt and aria2), Fedora (kernel-headers, kernel-tools, and openssh), openSUSE (webkit2gtk3), Oracle (perl), Red Hat (perl), SUSE (freerdp, python-urllib3, systemd, and wireshark), and Ubuntu (apt, poppler, and tiff).

Arguably, the most notable characteristic of persistent memory is that it is persistent: it retains its contents over power cycles. One other important aspect of these persistent-memory arrays that, we are told, will soon be everywhere, is their sheer size and low cost; persistent memory is a relatively inexpensive way to attach large amounts of memory to a system. Large, cheap memory arrays seem likely to be attractive to users who may not care about persistence and who can live with slower access speeds. Supporting such users is the objective of a pair of patch sets that have been circulating in recent months.

The 5.0-rc3 kernel prepatch has been released. "This rc is a bit bigger than usual. Partly because I missed a networking pull request for rc2, and as a result rc3 now contains _two_ networking pull updates. But part of it may also just be that it took a while for people to find and then fix bugs after the holiday season."

Security updates have been issued by Fedora (gitolite3, gvfs, php, radare2, and syslog-ng), Mageia (libssh, php, python-django16, and rdesktop), openSUSE (podofo), and SUSE (libraw, openssh, PackageKit, and wireshark).

Hardware memory encryption is, or will soon be, available on multiple generic CPUs. In its absence, data is stored — and passes between the memory chips and the processor — in the clear. Attackers may be able to access it by using hardware probes or by directly accessing the chips, which is especially problematic with persistent memory. One new memory-encryption offering is Intel's Multi-Key Total Memory Encryption (MKTME) [PDF]; AMD's equivalent is called Secure Encrypted Virtualization (SEV). The implementation of support for this feature is in progress for the Linux kernel. Recently, Alison Schofield proposed a user-space API for MKTME, provoking a long discussion on how memory encryption should be exposed to the user, if at all.

Security updates have been issued by Debian (drupal7), Fedora (electrum and perl-Email-Address), Mageia (gthumb), openSUSE (gitolite, kernel, krb5, libunwind, LibVNCServer, live555, mutt, wget, and zeromq), SUSE (krb5, mariadb, nodejs4, nodejs8, soundtouch, and zeromq), and Ubuntu (irssi).

The kernel's page cache works to improve performance by minimizing disk I/O and increasing the sharing of physical memory. But, like other performance-enhancing techniques that involve resources shared across security boundaries, the page cache can be abused as a way to extract information that should be kept secret. A recent paper [PDF] by Daniel Gruss and colleagues showed how the page cache can be targeted for a number of different attacks, leading to an abrupt change in how the mincore() system call works at the end of the 5.0 merge window. But subsequent discussion has made it clear that mincore() is just the tip of the iceberg; it is unclear what will really need to be done to protect a system against page-cache attacks or what the performance cost might be.