October 2020 - wlug - list.wlug.org.nz

Slashdot Asks: How Do You Feel About Btrfs?
by Peter Reutemann 25 Oct '20

25 Oct '20

'Linux Journal re-visiting the saga of the btrfs file system (initially designed at Oracle in 2007): The btrfs filesystem has taunted the Linux community for years, offering a stunning array of features and capability, but never earning universal acclaim. Btrfs is perhaps more deserving of patience, as its promised capabilities dwarf all peers, earning it vocal proponents with great influence. Still, [while] none can argue that btrfs is unfinished, many features are very new, and stability concerns remain for common functions. Most of the intended goals of btrfs have been met. However, Red Hat famously cut continued btrfs support from their 7.4 release, and has allowed the code to stagnate in their backported kernel since that time. The Fedora project announced their intention to adopt btrfs as the default filesystem for variants of their distribution, in a seeming juxtaposition. SUSE has maintained btrfs support for their own distribution and the greater community for many years. For users, the most desirable features of btrfs are transparent compression and snapshots; these features are stable, and relatively easy to add as a veneer to stock CentOS (and its peers). Administrators are further compelled by adjustable checksums, scrubs, and the ability to enlarge as well as (surprisingly) shrink filesystem images, while some advanced btrfs topics (i.e. deduplication, RAID, ext4 conversion) aren't really germane for minimal loopback usage. The systemd init package also has dependencies upon btrfs, among them machinectl and systemd-nspawn . Despite these features, there are many usage patterns that are not directly appropriate for use with btrfs. It is hostile to most databases and many other programs with incompatible I/O, and should be approached with some care. The original submission drew reactions from three disgruntled btrfs users. But the article goes on to explore providers of CentOS-compatible btrfs-enabled kernels, ultimately opining that "There are many 'rough edges' that are uncovered above with btrfs capabilities and implementations, especially with the measures taken to enable it for CentOS. Still, this is far better than ext2/3/4 and XFS, discarding all the desirable btrfs features, in that errors can be known because all filesystem content is checksummed." It would be helpful if the developers of btrfs and ZFS could work together to create a single kernel module, with maximal sharing of "cleanroom" code, that implemented both filesystems... Oracle is itself unwilling to settle these questions with either a GPL or BSD license release of ZFS. Oracle also delivers a btrfs implementation that is lacking in features, with inapplicable documentation, and out-of-date support tools (for CentOS 8 conversion). Oracle is the impediment, and a community effort to purge ZFS source of Oracle's contributions and unify it with btrfs seems the most straightforward option... It would also be helpful if other parties refrained from new filesystem efforts that lack the extensive btrfs functionality and feature set (i.e. Microsoft ReFS). Until such a day that an advanced filesystem becomes a ubiquitous commodity as Linux is as an OS, the user community will continue to be torn between questionable support, lack of features, and workarounds in a fragmented btrfs community. This is an uncomfortable place to be, and we would do well to remember the parties responsible for keeping us here. So how do Slashdot's readers feel about btrfs?' -- source: https://linux.slashdot.org/story/20/10/24/0146258 Cheers, Peter -- Peter Reutemann Dept. of Computer Science University of Waikato, NZ +64 (7) 577-5304 http://www.cms.waikato.ac.nz/~fracpete/ http://www.data-mining.co.nz/

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Google Patched an Actively-Exploited Zero-Day Bug in Chrome
by Peter Reutemann 25 Oct '20

25 Oct '20

'"Google released an update to its Chrome browser that patches a zero-day vulnerability in the software's FreeType font rendering library that was actively being exploited in the wild, Threatpost reported this week: Security researcher Sergei Glazunov of Google Project Zero discovered the bug which is classified as a type of memory-corruption flaw called a heap buffer overflow in FreeType. Glazunov informed Google of the vulnerability on Monday. Project Zero is an internal security team at the company aimed at finding zero-day vulnerabilities. By Tuesday, Google already had released a stable channel update, Chrome version 86.0.4240.111, that deploys five security fixes for Windows, Mac & Linux — among them a fix for the zero-day, which is being tracked as CVE-2020-15999 and is rated as high risk. "Google is aware of reports that an exploit for CVE-2020-15999 exists in the wild," Prudhvikumar Bommana of the Google Chrome team wrote in a blog post announcing the update Tuesday... "The fix is also in today's stable release of FreeType 2.10.4," Ben Hawkes, technical lead for the Project Zero team, tweeted. Meanwhile, security researchers took to Twitter to encourage people to update their Chrome browsers immediately to avoid falling victim to attackers aiming to exploit the flaw... In addition to the FreeType zero day, Google patched four other bugs — three of high risk and one of medium risk — in the Chrome update released this week... So far in the last 12 months Google has patched three zero-day vulnerabilities in its Chrome browser.' -- source: https://it.slashdot.org/story/20/10/25/029202 Cheers, Peter -- Peter Reutemann Dept. of Computer Science University of Waikato, NZ +64 (7) 577-5304 http://www.cms.waikato.ac.nz/~fracpete/ http://www.data-mining.co.nz/

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Chrome Caught Exempting Google Sites From User Requests To Delete Data
by Peter Reutemann 25 Oct '20

25 Oct '20

'This week the Verge reported: If you ask Chrome to delete all cookies and site data whenever you quit the browser, it's reasonable to expect that this policy applies to all websites. Recently, though, a bug in the browser meant data wasn't being removed for two sites in particular: Google and YouTube. This problem was first documented by iOS developer Jeff Johnson on his blog. Johnson found that in Chrome version 86.0.4240.75, "local storage" data for Google.com and YouTube.com stuck around even after restarting the browser. We've been able to replicate similar behavior... The Register notes that Chrome's behavior could allow Google to stash cookie-style data as site data, allowing it to track users even when they think they're being careful by deleting their cookie and site data every time they close the browser. In a statement, Google said it was aware of the issue and was working on a fix... At least one of the affected sites, YouTube, appears to have already been fixed. After we upgraded the Chrome browser to version 86.0.4240.111, YouTube's local storage data seems to successfully purge after a restart, although the data from Google.com still sticks around.' -- source: https://tech.slashdot.org/story/20/10/25/0155246 Cheers, Peter -- Peter Reutemann Dept. of Computer Science University of Waikato, NZ +64 (7) 577-5304 http://www.cms.waikato.ac.nz/~fracpete/ http://www.data-mining.co.nz/

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Options For ps
by Lawrence D'Oliveiro 25 Oct '20

25 Oct '20

One look at the man page for ps(1) <https://man7.org/linux/man-pages/man1/ps.1.html> and you see all the different traditional option syntaxes it tries to be compatible with. The BSD style doesn’t even prefix options with dashes, which can lead to ambiguities and is best avoided. If this is what you’re used to, try to wean yourself off it. To list some useful info about all processes, you can do ps -ef or, for even more info, try ps -eF One thing I find annoying about this it reports less precision in process start times for long-running processes. To get around this, you can use a custom format. For example ps -eo pid,ppid,lstart,tty,etime,cmd shows some similar info to the default “-f” format, but always includes start time and elapsed time to the nearest second, regardless of how long the process has been running. Another useful command to use with ps is pgrep(1) <https://man7.org/linux/man-pages/man1/pgrep.1.html>, which lets you filter processes to get information for according to various criteria. Or you could just use grep(1) on the output from ps, as I suspect a lot of people do. ;)

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Debian Donates 10,000 Euros to Fund Free and Decentralized Livestreaming
by Peter Reutemann 25 Oct '20

25 Oct '20

'PeerTube (developed by Framasoft) is "the free and decentralized alternative to video platforms, providing you over 400,000 videos published by 60,000 users and viewed over 15 million times," according to its web site. But now they're exploring livestreaming, writes Debian developer Phil Hands (Slashdot reader #2,365): Holding DebConf20 online this year highlighted the effort involved in setting up Live Streaming using Free Software — something that is beyond the reach of many smaller events which is where PeerTube with Live Streaming should be a perfect fit. In June PeerTube had posted a roadmap with a humble request for donations in lieu of a crowdfunding campaign: At a time when no one knows what the future holds, we deem it inappropriate to start a crowdfunding campaign and threaten not to do our best on PeerTube if we don't get the necessary funds. We believe in the public utility of PeerTube, so much so that we commit to working on it for six months to make this v3 happen, even if we must do it with our own funds (which we had already done for v2). We still hope that by sharing this roadmap as widely as possible, some of you will support us in our approach with a donation that will allow us to fund this project. And this week PeerTube's official Twitter feed announced that "Thanks to Debian's €10,000 donation we've just reached the 4th step of our PeerTube fundraising" — livestreaming. "Many thanks to all those who donated. And it's not too late to contribute." "We hope this unconventional gesture from the Debian project will help us make this year somewhat less terrible," added the Debian blog, "and give us, and thus humanity, better Free Software tooling to approach the future." It describes their donation as "a strong sign of recognition from an international project — one of the pillars of the Free Software world — towards a small French association which offers tools to liberate users from the clutches of the web's giant monopolies." And secondly, "it's a substantial amount of help in these difficult times, supporting the development of a tool which equally belongs to and is useful to everyone. The strength of Debian's gesture proves, once again, that solidarity, mutual aid and collaboration are values which allow our communities to create tools to help us strive towards Utopia."' -- source: https://linux.slashdot.org/story/20/10/24/010213 Cheers, Peter -- Peter Reutemann Dept. of Computer Science University of Waikato, NZ +64 (7) 577-5304 http://www.cms.waikato.ac.nz/~fracpete/ http://www.data-mining.co.nz/

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WHO To Grant Wikipedia Free Use of Its Published Material To Combat Covid Misinformation
by Peter Reutemann 23 Oct '20

23 Oct '20

'As part of efforts to stop the spread of false information about the coronavirus pandemic, Wikipedia and the World Health Organization announced a collaboration on Thursday: The health agency will grant the online encyclopedia free use of its published information, graphics and videos. The collaboration is the first between Wikipedia and a health agency. From a report: "We all consult just a few apps in our daily life, and this puts W.H.O. content right there in your language, in your town, in a way that relates to your geography," said Andrew Pattison, a digital content manager for the health agency who helped negotiate the contract. "Getting good content out quickly disarms the misinformation." Since its start in 2001, Wikipedia has become one of the world's 10 most consulted sites; it is frequently viewed for health information. The agreement puts much of the W.H.O.'s material into the Wikimedia "commons," meaning it can be reproduced or retranslated anywhere, without the need to seek permission -- as long as the material is identified as coming from the W.H.O. and a link to the original is included. "Equitable access to trusted health information is critical to keeping people safe and informed," said Tedros Adhanom Ghebreyesus, the W.H.O.'s director general. His agency translates its work into six official languages, which do not include, for example, Hindi, Bengali, German or Portuguese, so billions of people cannot read its documents in their native or even second language. Wikipedia articles, by contrast, are translated into about 175 languages. The first W.H.O. items used under the agreement are its "Mythbusters" infographics, which debunk more than two dozen false notions about Covid-19. Future additions could include, for example, treatment guidelines for doctors, said Ryan Merkley, chief of staff at the Wikimedia Foundation, which produces Wikipedia. If the arrangement works out, it could be extended to counter misinformation regarding AIDS, Ebola, influenza, polio and dozens of other diseases, Mr. Merkley said, "But this was something that just had to happen now." Eventually, live links will be established that would, for example, update global case and death numbers on Wikipedia as soon as the W.H.O. posts them, Mr. Pattison said.' -- source: https://news.slashdot.org/story/20/10/22/1833243 Cheers, Peter -- Peter Reutemann Dept. of Computer Science University of Waikato, NZ +64 (7) 577-5304 http://www.cms.waikato.ac.nz/~fracpete/ http://www.data-mining.co.nz/

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Firefox 'Site Isolation' Feature Enters User Testing, Expected Next Year
by Peter Reutemann 23 Oct '20

23 Oct '20

'Site Isolation is a modern browser security feature that works by separating each web page and web iframes in their own operating system process in order to prevent sites from tampering or stealing with each other's data. The feature was first deployed with Google Chrome in mid-2018, with the release of Chrome 67. Although initially, Site Isolation was meant to be deployed as a general improvement to Chrome's security posture, the feature came just in time to serve as a protective measure against the Spectre vulnerability impacting modern CPUs. Seeing the feature's success, Mozilla also announced plans to support it with the Firefox browser in February 2019, as part of an internal project codenamed Fission. For both Google and Mozilla, implementing Site Isolation was a time-consuming operation, requiring engineers to re-write large chunks of their browsers' internal architecture. The process took about two years for both Google and Mozilla. While Site Isolation is now a stable feature inside Chrome, this work is now nearing its completion inside Firefox. According to an update to the Project Fission wiki page, Site Isolation can now be enabled inside versions of Firefox Nightly, the Firefox version where new features are tested.' -- source: https://news.slashdot.org/story/20/10/22/1717203 Cheers, Peter -- Peter Reutemann Dept. of Computer Science University of Waikato, NZ +64 (7) 577-5304 http://www.cms.waikato.ac.nz/~fracpete/ http://www.data-mining.co.nz/

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Ubuntu Linux 20.10 'Groovy Gorilla' is Here With Renewed Raspberry Pi Focus
by Peter Reutemann 23 Oct '20

23 Oct '20

'As stated earlier, new Ubuntu versions come April and October, and wouldn't you know it, we are at the end of the latter. With Halloween a bit more than a week away, Canonical today releases Ubuntu 20.10. Ubuntu's version numbering scheme is based on year (YY), a period, and the month (MM). For instance, the previous stable version was released this past April and it is numbered as 20.04. In addition, Canonical (the operating system's owner) assigns names -- sequentially and alphabetically. The alphanumeric code name is always based on two words starting with the same sequential letter -- an adjective followed by an animal name. The aforementioned 20.04 is named "Focal Fossa." This time, the operating system will be called Ubuntu 20.10 "Groovy Gorilla." This new version of the desktop operating system is loaded with fixes, new features, and a renewed focus on the now-iconic Raspberry Pi. Yes, folks, with a compatible Pi (models with 4GB or 8GB of RAM), you can now have the full Ubuntu desktop experience.' -- source: https://news.slashdot.org/story/20/10/22/1737224 Cheers, Peter -- Peter Reutemann Dept. of Computer Science University of Waikato, NZ +64 (7) 577-5304 http://www.cms.waikato.ac.nz/~fracpete/ http://www.data-mining.co.nz/

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Vector Instructions: Everything Old Is New Again
by Lawrence D'Oliveiro 22 Oct '20

22 Oct '20

This article <https://www.sigarch.org/simd-instructions-considered-harmful/> (linked from <https://www.theregister.com/2020/10/21/sifive_vector_cpu_core/>) goes into how RISC-V implements vector instructions, and how this differs from the conventional SIMD approach taken by existing architectures like x86, ARM and MIPS. These CPUs add instructions that can operate on two, four or eight operands at once, in parallel. One drawback is that every new data type (and every new extension to dealing with greater parallelism) requires a new set of instructions, and so we a massive growth in the size of instruction sets for these machines over time. And then there is the trickiness of generating code using these instructions: even though you mostly leave it to the compiler to worry about this sort of thing nowadays, it still involves the generation of complicated sequences to set up a loop and deal with odd numbers of operands that don’t fit into the exact multiples that the instructions can deal with. So you wonder why a small sequence of source code can generate a whole lot of machine code. RISC-V, on the other hand, hearkens back to the grand-daddy of vector machines, the original Cray supercomputer family from the 1970s and 1980s. Here you have a vector-length register, which tells the CPU how many operands you have. You then set up operand pointer registers and write basically one instruction that operates on a single set of operands, and leave it to the hardware to automatically repeat this operation the required number of times, batching the iterations up to whatever size a particular implementation can handle in parallel. So the same code can run unchanged on future hardware with more parallel function units, and automatically take advantage of the greater performance.

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TrueNAS R-series hyperconverged appliances blend storage and compute
by Peter Reutemann 22 Oct '20

22 Oct '20

'Today, storage vendor iXsystems is launching a new R-series hyperconverged infrastructure appliance for its TrueNAS product line—and the first alpha release of TrueNAS SCALE, a Debian Linux-based version of the TrueNAS storage distribution. The new R-series appliances are designed to run either traditional, FreeBSD-based TrueNAS, or the new Debian-based TrueNAS SCALE. The series launches with four models—all rack-mounted—ranging from the 1U, 16-bay TrueNAS R10 to the up to 12U, 52 bay TrueNAS R50. All four models offer Ethernet connectivity up to dual 100GbE, as well as optional dual 32Gb Fibre Channel and Intel Xeon CPUs. The three larger models are expandable via separate JBOD shelves as well. TrueNAS itself is an OpenZFS-based storage distribution, which can be purchased preinstalled on NAS hardware or installed by users on their own generic PC equipment. It offers users the rich feature set of the ZFS filesystem—including block-level checksums and data healing, advanced storage topologies, atomic COW snapshots, rapid asymmetric replication, and more—along with a broad range of network sharing protocols, including SMB, NFS, sFTP, and iSCSI.' -- source: https://arstechnica.com/gadgets/2020/10/ixsystems-launches-new-hyperconverg… Cheers, Peter -- Peter Reutemann Dept. of Computer Science University of Waikato, NZ +64 (7) 577-5304 http://www.cms.waikato.ac.nz/~fracpete/ http://www.data-mining.co.nz/

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