Linux Weekly News

Security updates have been issued by CentOS (kernel and libldb), Debian (mediawiki, qemu, ruby-kramdown, and xen), Fedora (grub2, libldb, libopenmpt, python-pikepdf, python39, samba, squid, and webkit2gtk3), openSUSE (bcc, ceph, gssproxy, hostapd, isync, kernel, openexr, openSUSE KMPs, and tpm2-tss-engine), SUSE (fwupdate and wpa_supplicant), and Ubuntu (spamassassin).

The 5.12-rc7 kernel prepatch is out; it's rather larger than Linus would have liked. "End result: I'm still waffling about the final 5.12 release. The fact that we have a big rc7 does make me think that I'll probably do an rc8 this time around. But it ends up depending a bit on how the upcoming week goes, and if things are deathly quiet, I may end up deciding that an rc8 doesn't really make sense."

There is another set of stable kernel updates out: 5.11.13, 5.10.29, 5.4.111, 4.19.186, 4.14.230, 4.9.266, and 4.4.266. Each contains another set of important fixes.

HPVM ("heterogeneous parallel virtual machine") is a compiler for targets like GPUs and FPGAs based on LLVM; the 1.0 release is available now. "This release is a major addition to our first release (version 0.5), adding support for linear algebra tensor operations, Pytorch and Keras frontends, approximations for convolution operators, and an efficient and flexible framework for approximation tuning. Our novel approximation-tuner automatically selects approximation knobs for individual tensor operations and selects configurations that maximize a (configurable) performance objective."

The seccomp() mechanism allows the imposition of a filter program (expressed in "classic" BPF) that makes policy decisions on whether to allow each system call invoked by the target process. The user-space notification feature further allows those decisions to be deferred to another process. As this recent patch set from Sargun Dhillon shows, though, user-space notification still has some rough edges, especially when it comes to signals. This patch makes a simple change to try to address a rather complex problem brought to the fore by changes in the Go language's preemption model.

Security updates have been issued by Debian (lib3mf, php-pear, and python-django), Fedora (perl-Net-Netmask), openSUSE (flatpak, libostree, xdg-desktop-portal,, fwupd, fwupdate, and hostapd), Oracle (kernel, libldb, nettle, and squid), Red Hat (nettle), and SUSE (fwupdate, tpm2-tss-engine, and umoci).

Richard Stallman's return to the Free Software Foundation's board of directors has provoked a flurry of responses, and many organizations in the free-software community have expressed their unhappiness with that appointment. In almost every case, the process leading up to that expression has been carried out behind closed doors. The Debian project, instead, is deciding what to do in a classic Debian way — holding a public vote on a general resolution with a wide range of possible outcomes.

Security updates have been issued by Fedora (chromium, libldb, rpm, samba, and seamonkey), openSUSE (isync), Oracle (kernel), Red Hat (openssl and squid), SUSE (ceph, flatpak, libostree, xdg-desktop-portal, xdg-desktop-portal-gtk, fwupd, fwupdate, and openexr), and Ubuntu (curl, linux-lts-trusty, and lxml).

The LWN.net Weekly Edition for April 8, 2021 is available.

Five years ago, we looked at an effort to assist in the assignment of Common Vulnerabilities and Exposures (CVE) IDs, especially for open-source projects. Developers in the free-software world have often found it difficult to obtain CVE IDs for the vulnerabilities that they find. The Distributed Weakness Filing (DWF) project was meant to reduce the friction in the CVE-assignment process, but it never really got off the ground. In a blog post, Josh Bressers said that DWF was hampered by trying to follow the rules for CVEs. That has led to a plan to restart DWF, but this time without the "yoke of legacy CVE".

Projects, even of the open-source variety, sometimes have secrets that need to be maintained. They can range from things like signing keys, which are (or should be) securely stored away from the project's code, to credentials and tokens for access to various web-based services, such as cloud-hosting services or the Python Package Index (PyPI). These credentials are sometimes needed by instances of the running code, and some others benefit from being stored "near" the code, but these types of credentials are not meant to be distributed outside of the project. They can sometimes mistakenly be added to a public repository, however, which is a slip that attackers are most definitely on the lookout for. The big repository-hosting services like GitHub and GitLab are well-placed to scan for these kinds of secrets being committed to project repositories—and they do.

Stable kernels 5.11.12, 5.10.28, 5.4.110, 4.19.185, 4.14.229, 4.9.265, and 4.4.265 have been released with the usual set of important fixes. Users should upgrade.

Security updates have been issued by openSUSE (chromium), Oracle (flatpak and kernel), Red Hat (virt:8.3 and virt-devel:8.3), and SUSE (gssproxy and xen).

The Mozilla Hacks site has a report on the use of ThreadSanitizer to detect and fix data races in the Firefox browser. "While benign data races do exist, we found that data races are very easily misclassified as benign. The reasons for this are clear: It is hard to reason about what compilers can and will optimize, and confirmation for certain 'benign' data races requires you to look at the assembler code that the compiler finally produces. Needless to say, this procedure is often much more time consuming than fixing the actual data race and also not future-proof. As a result, we decided that the ultimate goal should be a 'no data races' policy that declares even benign data races as undesirable due to their risk of misclassification, the required time for investigation and the potential risk from future compilers (with better optimizations) or future platforms (e.g. ARM)."

Security updates have been issued by Debian (chromium, netty, python-bleach, and python3.5), Fedora (libmediainfo, libzen, and mediainfo), Mageia (openssl), openSUSE (chromium), Red Hat (389-ds:1.4, flatpak, kernel, kernel-rt, kpatch-patch, libldb, and virt:rhel and virt-devel:rhel), and Ubuntu (python-django and ruby-rack).

Kees Cook has posted a long list of security-related improvements that made it into the 5.9 kernel release. "Sasha Levin, Andy Lutomirski, Chang S. Bae, Andi Kleen, Tony Luck, Thomas Gleixner, and others landed the long-awaited FSGSBASE series. This provides task switching performance improvements while keeping the kernel safe from modules accidentally (or maliciously) trying to use the features directly (which exposed an unprivileged direct kernel access hole)."

Version 3.2 of the Django web framework is out; it has been designated as a long-term-support release. New features include automatic AppConfig discovery, functional indexes, pymemcache support, and more; see the release notes for details.

The recent proposal from David Hildenbrand to remove support for the /dev/kmem special file has not sparked a lot of discussion. Perhaps that is because today's youngsters, lacking an understanding of history, may be wondering what that file is in the first place and, thus, be unclear on why it may matter. Chances are that /dev/kmem will not be missed, but in passing it takes away a venerable part of the Unix kernel interface.

Security updates have been issued by Debian (libxstream-java, php-nette, and smarty3), Fedora (curl, openssl, spamassassin, and webkit2gtk3), Mageia (ant, batik, kernel, kernel-linus, nodejs-chownr, nodejs-yargs-parser, python-bottle, and ruby-em-http-request), openSUSE (curl and OpenIPMI), and Red Hat (openssl).

The long saga of Oracle's copyright-infringement against Google, which copied much of the Java API for use in Android, has come to an end with this ruling [PDF] in favor of Google. "Google’s purpose was to create a different task-related system for a different computing environment (smartphones) and to create a platform—the Android platform—that would help achieve and popularize that objective. The record demonstrates numerous ways in which reimplementing an interface can further the development of computer programs. Google’s purpose was therefore consistent with that creative progress that is the basic constitutional objective of copyright itself."