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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 16 min ago

Varda: The Mysterious Fiber Bomb Problem: A Debugging Story

3 hours 16 min ago
Over at the Sandstorm Blog, project founder Kenton Varda relates a debugging war story. Sandstorm web servers would mysteriously peg the CPU around once a week, slowing request processing to a crawl, seemingly at random. "Obviously, we needed to take a CPU profile while the bug was in progress. Of course, the bug only reproduced in production, therefore we’d have to take our profile in production. This ruled out any profiling technology that would harm performance at other times – so, no instrumented binaries. We’d need a sampling profiler that could run on an existing process on-demand. And it would have to understand both C++ and V8 Javascript. (This last requirement ruled out my personal favorite profiler, pprof from google-perftools.) Luckily, it turns out there is a correct modern answer: Linux’s “perf” tool. This is a sampling profiler that relies on Linux kernel APIs, thus not requiring loading any code into the target binary at all, at least for C/C++. And for Javascript, it turns out V8 has built-in support for generating a “perf map”, which tells the tool how to map JITed code locations back to Javascript source: just pass the --perf_basic_prof_only_functions flag on the Node command-line. This flag is safe in production – it writes some data to disk over time, but we rebuild all our VMs weekly, so the files never get large enough to be a problem."

Friday's security advisories

8 hours 15 min ago

Arch Linux has updated c-ares (code execution) and wordpress (multiple vulnerabilities).

CentOS has updated python-twisted-web (C7; C6: HTTP proxy redirect).

Debian has updated wordpress (multiple vulnerabilities).

Debian-LTS has updated chicken (two vulnerabilities), firefox-esr (regression in previous security update), icedove (multiple vulnerabilities), and ruby-activesupport-3.2 (access restriction bypass).

Fedora has updated curl (F23: code execution) and php-adodb (F24; F23: SQL injection).

openSUSE has updated libgcrypt (42.1: flawed random number generation), openjpeg (42.1: denial of service), and postgresql93 (13.2: two vulnerabilities).

Oracle has updated python-twisted-web (OL7; OL6: HTTP proxy redirect).

Red Hat has updated python-twisted-web (RHEL7&6: HTTP proxy redirect).

SUSE has updated pidgin (SLE11: multiple vulnerabilities) and postgresql94 (SLE11: two vulnerabilities).

Stable kernels 4.7.6 and 4.4.23

16 hours 56 min ago
Greg Kroah-Hartman has released the 4.7.6 and 4.4.23 stable kernels with the usual set of important fixes.

Security updates for Thursday

Thursday 29th of September 2016 06:39:57 PM

CentOS has updated bind (C7; C6; C5: denial of service), bind97 (C5: denial of service), kvm (C5: two vulnerabilities), and openssl (C7; C6: multiple vulnerabilities).

Fedora has updated vfrnav (F24: unspecified).

Oracle has updated bind (OL7; OL6; OL5: denial of service) and bind97 (OL5: denial of service).

Scientific Linux has updated bind (denial of service), bind97 (SL5: denial of service), kvm (SL5: two vulnerabilities), and openssl (SL7&6: multiple vulnerabilities).

SUSE has updated postgresql93 (SLE12: two vulnerabilities) and postgresql94 (SLE12: two vulnerabilities).

Ubuntu has updated clamav (16.04, 14.04, 12.04: three code execution flaws), samba (16.04, 14.04: crypto downgrade), and systemd (16.04: denial of service).

Qubes OS 3.2 released

Thursday 29th of September 2016 02:20:53 PM
Version 3.2 of the Qubes OS distribution is available. "This is an incremental improvement over the 3.1 version that we released earlier this year. A lot of work went into making this release more polished, more stable and easier to use than our previous releases." Changes include a new management infrastructure, the ability to assign individual USB devices to virtual machines and a switch to the Xfce4 desktop. See the release notes for details.

PostgreSQL 9.6 released

Thursday 29th of September 2016 02:04:31 PM
The PostgreSQL 9.6 release is available. "This release will allow users to both scale up and scale out high performance database workloads. New features include parallel query, synchronous replication improvements, phrase search, and improvements to performance and usability, as well as many more features." See the announcement text and the release notes for more information.

[$] LWN.net Weekly Edition for September 29, 2016

Thursday 29th of September 2016 01:12:29 AM
The LWN.net Weekly Edition for September 29, 2016 is available.

Debian Project mourns the loss of Kristoffer H. Rose

Wednesday 28th of September 2016 04:27:21 PM
Ana Guerrero Lopez sadly reports that Kristoffer H. Rose died on September 17. "Kristoffer was a Debian contributor from the very early days of the project, and the upstream author of several packages that are still in the Debian archive nowadays, such as the LaTeX package Xy-pic and FlexML. On his return to the project after several years' absence, many of us had the pleasure of meeting Kristoffer during DebConf15 in Heidelberg. The Debian Project honours his good work and strong dedication to Debian and Free Software. Kristoffer's broad technical knowledge and his ability to share that knowledge with others will be missed. The contributions of Kristoffer will not be forgotten, and the high standards of his work will continue to serve as an inspiration to others."

Security advisories for Wednesday

Wednesday 28th of September 2016 04:19:04 PM

Arch Linux has updated bind (denial of service), lib32-openssl (denial of service), and openssl (denial of service).

Debian has updated bind9 (two denial of service flaws).

Fedora has updated jansson (F24; F23: denial of service) and openssl (F24: multiple vulnerabilities).

Mageia has updated autotrace (code execution), firefox/rootcerts/nss (multiple vulnerabilities), gnutls (certificate verification bypass), graphicsmagick (multiple vulnerabilities), pdns (three denial of service flaws), thunderbird (multiple vulnerabilities), wget (two vulnerabilities), and zookeeper (buffer overflow).

openSUSE has updated bind (Leap42.1, 13.2: denial of service), freerdp (Leap42.1; 13.2: two vulnerabilities), and openssl (Leap42.1: multiple vulnerabilities).

Oracle has updated kvm (OL5: two vulnerabilities) and openssl (OL7; OL6: multiple vulnerabilities).

Red Hat has updated bind (RHEL5,6,7: denial of service), bind97 (RHEL5: denial of service), kernel (RHEL6.6: information leak), and kvm (RHEL5: two vulnerabilities).

Slackware has updated bind (denial of service).

SUSE has updated bind (SLE12-SP1; SLES12; SOSC5, SMP2.1, SM2.1, SLE11-SP4: denial of service), mariadb (SLE12-SP1; SLES12: SQL injection/privilege escalation), openssl (SLE12-SP1: multiple vulnerabilities), and php5 (SLESDK12-SP1, SLEM12: multiple vulnerabilities).

Ubuntu has updated bind9 (denial of service) and Pillow (14.04: multiple vulnerabilities).

Firefox OS, B2G OS, and Gecko

Tuesday 27th of September 2016 06:31:07 PM
Ari Jaaksi and David Bryant posted a note to the B2G (Boot to Gecko) OS community looking at the end of Firefox OS development and at what happens to the code base going forward. "In the spring and summer of 2016 the Connected Devices team dug deeper into opportunities for Firefox OS. They concluded that Firefox OS TV was a project to be run by our commercial partner and not a project to be led by Mozilla. Further, Firefox OS was determined to not be sufficiently useful for ongoing Connected Devices work to justify the effort to maintain it. This meant that development of the Firefox OS stack was no longer a part of Connected Devices, or Mozilla at all. Firefox OS 2.6 would be the last release from Mozilla. Today we are announcing the next phase in that evolution. While work at Mozilla on Firefox OS has ceased, we very much need to continue to evolve the underlying code that comprises Gecko, our web platform engine, as part of the ongoing development of Firefox. In order to evolve quickly and enable substantial new architectural changes in Gecko, Mozilla’s Platform Engineering organization needs to remove all B2G-related code from mozilla-central. This certainly has consequences for B2G OS. For the community to continue working on B2G OS they will have to maintain a code base that includes a full version of Gecko, so will need to fork Gecko and proceed with development on their own, separate branch." (Thanks to Paul Wise)

Tuesday's security updates

Tuesday 27th of September 2016 03:31:02 PM

Arch Linux has updated gnutls (certificate verification bypass), lib32-gnutls (certificate verification bypass), lib32-openssl (multiple vulnerabilities), openssl (multiple vulnerabilities), and wireshark-cli (multiple vulnerabilities).

Debian has updated jackrabbit (cross-site request forgery) and python-django (cross-site request forgery).

Debian-LTS has updated firefox-esr (multiple vulnerabilities).

Fedora has updated community-mysql (F24: SQL injection/privilege escalation).

openSUSE has updated firefox, nss (13.1: multiple vulnerabilities) and openssl (13.2: multiple vulnerabilities).

Red Hat has updated openssl (RHEL6,7: multiple vulnerabilities).

Slackware has updated openssl (denial of service).

SUSE has updated openssl (SLES12: multiple vulnerabilities).

Ubuntu has updated python-django (cross-site request forgery).

[$] Systemd programming, 30 months later

Tuesday 27th of September 2016 02:11:24 PM

Some time ago, we published a pair of articles about systemd programming that extolled the value of providing high-quality unit files in upstream packages. The hope was that all distributions would use them and that problems could be fixed centrally rather than each distribution fixing its own problems independently. Now, 30 months later, it seems like a good time to see how well that worked out for nfs-utils, the focus of much of that discussion. Did distributors benefit from upstream unit files, and what sort of problems were encountered?

Announcing the KDE Advisory Board

Monday 26th of September 2016 09:21:30 PM
KDE e.V. introduces the KDE Advisory Board. "One of the core goals of the Advisory Board is to provide KDE with insights into the needs of the various organizations that surround us. We are very aware that we need the ability to combine our efforts for greater impact and the only way we can do that is by adopting a more diverse view from outside of our organization on topics that are relevant to us. This will allow all of us to benefit from one another's experience."

Security advisories for Monday

Monday 26th of September 2016 04:23:59 PM

Debian has updated imagemagick (code execution), libarchive (three vulnerabilities), openssl (regression in previous update), and unadf (two vulnerabilities).

Debian-LTS has updated dropbear (two vulnerabilities), dwarfutils (two vulnerabilities), mactelnet (code execution), openssl (multiple vulnerabilities), and policycoreutils (sandbox escape).

Fedora has updated bash (F24; F23: code execution) and firefox (F24; F23: multiple vulnerabilities).

Gentoo has updated bundler (installs malicious gem files) and qemu (multiple vulnerabilities).

Mageia has updated gdk-pixbuf2.0 (denial of service), golang (denial of service), libarchive (file overwrite), libtorrent-rasterbar (denial of service), php (multiple vulnerabilities), and wireshark (multiple vulnerabilities).

openSUSE has updated curl (Leap42.1: multiple vulnerabilities), flash-player (13.1: multiple vulnerabilities), gd (Leap42.1: multiple vulnerabilities), gtk2 (Leap42.1; 13.2: code execution), firefox, nss (Leap42.1, 13.2: multiple vulnerabilities), samba (Leap42.1: crypto downgrade), thunderbird (13.1: multiple vulnerabilities), tiff (13.1: multiple vulnerabilities), and wpa_supplicant (Leap42.1: multiple vulnerabilities).

Slackware has updated php (multiple vulnerabilities).

Ubuntu has updated openssl (regression in previous update).

OpenSSL security advisory for September 26

Monday 26th of September 2016 01:12:27 PM
This OpenSSL security advisory is notable in that it's the second one in four days; sites that updated after the first one may need to do so again. "This security update addresses issues that were caused by patches included in our previous security update, released on 22nd September 2016. Given the Critical severity of one of these flaws we have chosen to release this advisory immediately to prevent upgrades to the affected version, rather than delaying in order to provide our usual public pre-notification."

Kernel prepatch 4.8-rc8

Monday 26th of September 2016 01:04:15 PM
The 4.8-rc8 kernel prepatch is out. "Things actually did start to calm down this week, but I didn't get the feeling that there was no point in doing one final rc, so here we are. I expect the final 4.8 release next weekend, unless something really unexpected comes up."

Prodromou: Adopt a pump.io server

Monday 26th of September 2016 08:27:59 AM

Evan Prodromou, creator of identi.ca and pump.io, has put a call out for interested parties to adopt the administration of public pump.io microblogging servers, which he is currently funding out of his own pocket. "Almost all of them are on $5/month Digital Ocean droplets, which makes them relatively cheap for a single person to support. If you decide you want to adopt a server, E14N will sell you the domain and all the software and data for $1. But you'll be obligated to keep the server running pump.io for at least a year, and if you decide you don't want to run it, you have to sell it back to me." There are currently around 25 servers in the federated network initially started by Prodromou, which does not count other pump.io instances. He notes that one important exception is the identi.ca site, which is significantly larger than the rest, and which he would like to find a trusted non-profit organization to maintain.

Stable kernel updates 4.7.5 and 4.4.22

Saturday 24th of September 2016 02:02:46 PM
The 4.7.5 and 4.4.22 stable kernel updates are available. These are relatively large updates containing the usual important fixes.

Mitchell: The MIT License, Line by Line

Friday 23rd of September 2016 04:11:19 PM

At his blog, Kyle E. Mitchell ("who is not your attorney") takes a close, line-by-line reading of the popular MIT software license. The details he points out begin on line one with the license's title: "'The MIT License' is a not a single license, but a family of license forms derived from language prepared for releases from the Massachusetts Institute of Technology. It has seen a lot of changes over the years, both for the original projects that used it, and also as a model for other projects. The Fedora Project maintains a kind of cabinet of MIT license curiosities, with insipid variations preserved in plain text like anatomical specimens in formaldehyde, tracing a wayward kind of evolution."

Despite the license being only 171 words, Mitchell finds quite a bit to expand on, such as the ambiguities of the phrase "to deal in the Software without restriction": "As a result of this mishmash of legal, industry, general-intellectual-property, and general-use terms, it isn’t clear whether The MIT License includes a patent license. The general language 'deal in' and some of the example verbs, especially 'use', point toward a patent license, albeit a very unclear one. The fact that the license comes from the copyright holder, who may or may not have patent rights in inventions in the software, as well as most of the example verbs and the definition of 'the Software' itself, all point strongly toward a copyright license." Nevertheless, Mitchell notes, "despite some crusty verbiage and lawyerly affectation, one hundred and seventy one little words can get a hell of a lot of legal work done."

Friday's security updates

Friday 23rd of September 2016 01:55:01 PM

Debian has updated firefox-esr (multiple vulnerabilities).

Debian-LTS has updated wordpress (multiple vulnerabilities).

Fedora has updated distribution-gpg-keys (F23: privilege escalation), mock (F23: privilege escalation), openvas-libraries (F24; F23: multiple vulnerabilities), openvas-scanner (F24; F23: denial of service), and shiro (F24: access control bypass).

openSUSE has updated pdns (13.2, Leap 42.1: multiple vulnerabilities).

Oracle has updated kernel (4.1.12 O6; O7: multiple vulnerabilities; 3.8.13 O7; O6: multiple vulnerabilities; 2.6.39 O6; O5: multiple vulnerabilities).

Slackware has updated openssl (14.0, 14.1, 14.2, -current: multiple vulnerabilities) and pidgin (13.0, 13.1, 13.137, 14.0, 14.1: mysterious vulnerabilities).

Ubuntu has updated openssl (12.04, 14.04, 16.04: multiple vulnerabilities).