- wlug - list.wlug.org.nz

Fast Restart For Java Apps
by Lawrence D'Oliveiro 23 May '23

23 May '23

Java continues to be popular for server-side apps. But one problem is that starting a Java app can be slow. So if you have some Java code that performs a service on demand, runs for a short while and then shuts down again, that hurts performance. Enter “CRaC”, or “Coordinated Restore at Checkpoint” <https://devclass.com/2023/05/22/azul-makes-openjdk-with-fast-start-crac-gen…>, from a company called Azul, which seems to centre its entire business around OpenJDK <https://www.azul.com/about/>. This system lets the app dump its state to disk in a form that allows for quick resumption. This state cannot include things like open files/network connections, so the app itself needs to implement handlers to close these before the dump and reopen them after the restore, saving enough state as part of the dump to allow this to happen with minimal impact on the rest of the application. Interestingly, this system is built on another piece of software called “CRIU” or “Checkpoint/Restore In Userspace” <https://criu.org/Main_Page>, which is Linux-only. As Azul’s CTO says: “We submitted CRaC to OpenJDK as an idea for a project … and they’ve included it as one of the many project they have. The reason it isn’t in the mainstream yet, and I’m not even sure it will make it into the mainstream, is that we rely on the CRIU technology underneath on Linux, and there isn’t an equivalent that we’re aware of on Windows or on Mac. So you lose that cross-platform functionality … ” But as the article says, that may not such a big showstopper any more: Java applications are often developed on Windows or Mac, but most often deployed to Linux, suggesting that the lack of cross-platform support is not a deal-breaker for everyone.

1 0

Fibre Connection -- Separating Modem & Router Functions
by Lawrence D'Oliveiro 16 May '23

16 May '23

Most people probably have their internet connection provided through a single box. There are two separate functions going on: * “Modem” (layer 2) -- handling the low-level signalling with whatever is at the other end of the wire (whether copper or glass); * “Router” (layer 3) -- routing TCP/IP packets between your house LAN and your ISP, which provides the connection between there and the rest of the Internet. At one point I was running a cheap little Conexant AccessRunner USB box (bought from Dick Smith) on my ADSL connection; while this could also perform both functions in one, I found a version of the firmware that implemented only the modem function. Plugging this into a Linux box caused it to appear like an additional network interface (the drivers are already in the standard kernel). I could then control this via the “ppp” package <https://ppp.samba.org/>, using its PPP-over-ATM plugin to implement the correct low-level signalling (just VPI/VCI selection, really). I could then exploit the full power of the Linux network stack on that box to manage the connection to the rest of my house LAN. Anyway, as my own house gets wired up for fibre (soon...), I was curious as to whether something equivalent could be done for a fibre connection. And the information I’ve found so far (e.g. <https://www.geekzone.co.nz/forums.asp?forumid=81&topicid=274586>) indicates it might actually be simpler than this. The “ONT” (“Optical Network Terminator”) box that gets installed in your house has phone ports and Ethernet ports on it, and it appears that (once you have your ISP connection up and running) the Ethernet connection behaves just like a regular LAN connection, with a DHCP server (and ISP’s router) listening on the other end. So instead of an Internet router at your end, you can plug a regular PC directly into that port, pick up an allocated address, and have it immediately connected to the Internet. In short, there is nothing fibre-specific about the Internet router that the ISP provides to you at all. However, there might be issues with VLAN-tagging of the Ethernet frames, and this is not standardized between ISPs. (By the way, I see several folks claiming there is no “modem” in a fibre connection. Of course there is.) Not sure whether I’ll try this right away. Might be safest to do things the ISP-provided way, at least to begin with.

4 8

Unkillable UEFI Malware Bypassing Secure Boot Enabled By Unpatchable Windows Flaw
by Peter Reutemann 12 May '23

12 May '23

'Researchers have announced a major cybersecurity find -- the world's first-known instance of real-world malware that can hijack a computer's boot process even when Secure Boot and other advanced protections are enabled and running on fully updated versions of Windows. From a report: Dubbed BlackLotus, the malware is what's known as a UEFI bootkit. These sophisticated pieces of malware hijack the UEFI -- short for Unified Extensible Firmware Interface -- the low-level and complex chain of firmware responsible for booting up virtually every modern computer. As the mechanism that bridges a PC's device firmware with its operating system, the UEFI is an OS in its own right. It's located in an SPI-connected flash storage chip soldered onto the computer motherboard, making it difficult to inspect or patch. Because the UEFI is the first thing to run when a computer is turned on, it influences the OS, security apps, and all other software that follows. These traits make the UEFI the perfect place to run malware. When successful, UEFI bootkits disable OS security mechanisms and ensure that a computer remains infected with stealthy malware that runs at the kernel mode or user mode, even after the operating system is reinstalled or a hard drive is replaced. As appealing as it is to threat actors to install nearly invisible and unremovable malware that has kernel-level access, there are a few formidable hurdles standing in their way. One is the requirement that they first hack the device and gain administrator system rights, either by exploiting one or more vulnerabilities in the OS or apps or by tricking a user into installing trojanized software. Only after this high bar is cleared can the threat actor attempt an installation of the bootkit. The second thing standing in the way of UEFI attacks is UEFI Secure Boot, an industry-wide standard that uses cryptographic signatures to ensure that each piece of software used during startup is trusted by a computer's manufacturer. Secure Boot is designed to create a chain of trust that will prevent attackers from replacing the intended bootup firmware with malicious firmware. If a single firmware link in that chain isn't recognized, Secure Boot will prevent the device from starting.' -- source: https://it.slashdot.org/story/23/03/06/1854200 Cheers, Peter -- Peter Reutemann Dept. of Computer Science University of Waikato, Hamilton, NZ Mobile +64 22 190 2375 https://www.cs.waikato.ac.nz/~fracpete/ http://www.data-mining.co.nz/

2 2

OpenOffice: The One FOSS Project That Deserves To Die, But Won’t
by Lawrence D'Oliveiro 06 May '23

06 May '23

The ever-dependable Brodie Robertson has a look at the ongoing (!) development history of OpenOffice here <https://www.youtube.com/watch?v=xdpMxmFvGBA>. Those of us on FOSS platforms moved to LibreOffice years ago. But among some sectors (my guess is, predominantly Microsoft Windows users?), OpenOffice still has the dominant name recognition. And just to add to the fun, the project actually continues putting out updates! Though these are just minor ones -- I don’t think there have been any major functional changes in the better part of a decade. The source code commit history also continues to bubble over, though a lot of the patches are tiny, almost trivial things, like fixing typos and making random-looking changes to whitespace.

1 0

I used System76’s Pangolin for weeks, and Linux was not the biggest problem
by Peter Reutemann 05 May '23

05 May '23

'After using System76’s Pangolin as my primary work laptop for nearly six weeks, I can tell you this: If you need a 15-inch Linux-focused laptop, this is the one to get. The Pangolin is a solid device, designed more for dependability and convenience than ultrabook portability or cutting-edge parts, but it still has reasonably modern hardware (especially its 144 Hz screen). The Pangolin and its native Pop!_OS are a showcase for how remarkably normal Linux can feel as a daily driver in 2023. Normal, and with lots of ports. It’s hard to do a nuts-and-bolts comparison of the Pangolin to most other laptops, due largely to benchmark comparability between Linux and most laptops running Windows or macOS. But it’s also not entirely necessary. There’s only one real version of the Pangolin available—one processor, one amount of RAM, then variable, user-expandable storage. We’ll show you how the Pangolin did on a couple tests. But how this laptop works for you is much more about what you’re bringing to it and what you're willing to put into customizing it to your liking. I came to the Pangolin as someone who has made a few attempts at using Linux as a daily driver. I know enough command line, vim, and Unix-based architecture to be conversant, and I have two Raspberry Pis that are constantly being improved. Still, I'm more hobbyist than practitioner. And yet the Pangolin presented no real problems as I used it for almost any task I needed to get done. Its combination of solid software and practical hardware choices make it an easy system to recommend, so long as you know you need Linux. Its maker-made operating system, Pop!_OS, almost never gave me problems, except when I was trying to make it run benchmarks. Starting with a rock-solid Linux install, where every bit of hardware is supported and functional, made me more eager to poke at the edges and see what I could customize.' -- source: https://arstechnica.com/gadgets/2023/05/review-system76-pangolin-is-a-solid… Cheers, Peter -- Peter Reutemann Dept. of Computer Science University of Waikato, Hamilton, NZ Mobile +64 22 190 2375 https://www.cs.waikato.ac.nz/~fracpete/ http://www.data-mining.co.nz/

1 0

'sudo' and 'su' Are Being Rewritten In Rust For Memory Safety
by Peter Reutemann 02 May '23

02 May '23

'Phoronix reports: With the financial backing of Amazon Web Services, sudo and su are being rewritten in the Rust programming language in order to increase the memory safety for the widely relied upon software... to further enhance Linux/open-source security. "[B]ecause it's written in C, sudo has experienced many vulnerabilities related to memory safety issues," according to a blog post announcing the project: It's important that we secure our most critical software, particularly from memory safety vulnerabilities. It's hard to imagine software that's much more critical than sudo and su. This work is being done by a joint team from Ferrous Systems and Tweede Golf with generous support from Amazon Web Services. The work plan is viewable here. The GitHub repository is here. ' -- source: https://linux.slashdot.org/story/23/05/01/0020239 Cheers, Peter -- Peter Reutemann Dept. of Computer Science University of Waikato, Hamilton, NZ Mobile +64 22 190 2375 https://www.cs.waikato.ac.nz/~fracpete/ http://www.data-mining.co.nz/

1 0

Linux Foundation Announces DentOS 3.0, an Open Source Network OS for Disaggregated Networks
by Peter Reutemann 01 May '23

01 May '23

'This month the Linux Foundation announced version 3.0 of DentOS, an open source network operating system using the Linux kernel, Switchdev, and other Linux-based projects for a standardized network operating system "without abstractions or overhead," according to the project's web page. "All underlying infrastructure — including ASIC and Silicon for networking and datapath — is treated equally; while existing abstractions, APIs, drivers, low-level overhead, and other open software are simplified. DENT unites silicon vendors, ODMs, SIs, OEMs, and end users across all verticals to enable the transition to disaggregated networks." Or, as the Linux Foundation, the operating system provides "a flexible and customizable platform for network administrators to manage their networks." DENT provides access to open source-based switches at a lower cost and with more flexibility compared to proprietary switches with locked ecosystems. Network wiring closets in many facilities--including retail stores, warehousing, remote locations, enterprises, and small and mid-sized businesses--are often small, requiring a compact solution for network management. Additionally, staff expertise may be limited, and branch-office switches from leading suppliers can require costly contracts. DENT can be easily deployed on white-box hardware in small spaces, providing an efficient and cost-effective solution for network management. As a result, DENT deployment can significantly enhance network management in a wide range of environments, providing greater efficiency, reliability, and scalability... DentOS enables Amazon's Just Walk Out Technology to connect and manage thousands of devices like cameras, sensors, entry and exit gates, and access points on the network edge. ' -- source: https://tech.slashdot.org/story/23/04/30/010222 Cheers, Peter -- Peter Reutemann Dept. of Computer Science University of Waikato, Hamilton, NZ Mobile +64 22 190 2375 https://www.cs.waikato.ac.nz/~fracpete/ http://www.data-mining.co.nz/

1 0

Not-So-Stupid(?) Linux Trick
by Lawrence D'Oliveiro 28 Apr '23

28 Apr '23

Here’s a command that can sometimes look a bit unnerving in operation, but is actually quite safe: rmdir -p «dir» where «dir» is some directory. Or to watch the whole process in action, add the option to give progress messages: rmdir -pv «dir» Background: the basic command rmdir «dir» deletes the named directory, but only if it is empty. The “-p” option takes this further, by then trying to delete the parent of «dir», and if that succeeds, the parent of that, and so on. It stops only when it gets to a nonempty directory, or when it has done all components of «dir». So if, for example, you try this on an absolute path, this will mean the command always stops on an error. And the error could quite likely be on a directory which contains important stuff that you care about. But, as I said, it’s quite safe, since it won’t delete that stuff. But I told you it could be unnerving, didn’t I?

1 0

New Intel Linux Graphics Driver Patches Released, Up To 10-15% Better Performance
by Peter Reutemann 28 Apr '23

28 Apr '23

'A new set of patches have been released for the Intel Linux graphics driver that "can provide 10-15% better performance when operating in the tuned mode," reports Phoronix. From the report: The set of Intel i915 Linux kernel graphics driver patches are about exposing the Intel RPS (Requested Power State) up/down thresholds. Right now the Intel Linux kernel driver has static values set for the up/down thresholds between power states while these patches would make them dynamically configurable by user-space. Google engineer Syed Faaiz Hussain raised the issue that they experimented with the Intel RPS tuning and were able to manage up to 15% better performance. With Counter-Strike: Global Offensive with OpenGL was a 14.5% boost, CS:GO with Vulkan was 12.9% faster, and Civilization VI with OpenGL was 11% faster while Strange Brigade was unchanged. No other game numbers were provided. But as this is about changing the threshold for how aggressively the Intel graphics hardware switches power states, the proposed patches leave it up to user-space to adjust the thresholds as they wish. Google engineers are interested in hooking this into Feral's GameMode so that the values could be automatically tuned when launching games and then returning to their former state when done gaming, in order to maximize battery life / power efficiency. The only downside with these current patches are that they work only for non-GuC based platforms... So the latest Alder/Raptor Lake notebooks as well as Intel DG2/Alchemist discrete graphics currently aren't able to make use of this tuning option. ' -- source: https://tech.slashdot.org/story/23/04/27/1927209 Cheers, Peter -- Peter Reutemann Dept. of Computer Science University of Waikato, Hamilton, NZ Mobile +64 22 190 2375 https://www.cs.waikato.ac.nz/~fracpete/ http://www.data-mining.co.nz/

1 0

Linux Kernel 6.3 Released
by Peter Reutemann 27 Apr '23

27 Apr '23

'A report from ZDNet, written by Steven Vaughan-Nichols: The latest Linux kernel is out with a slew of new features -- and, for once, this release has been nice and easy. [...] Speaking of Rust, everyone's favorite memory-safe language, the new kernel comes with user-mode Linux support for Rust code. Miguel Ojeda, the Linux kernel developer, who's led the efforts to bring Rust to Linux, said the additions mean we're, "getting closer to a point where the first Rust modules can be upstreamed." Other features in the Linux 6.3 kernel include support and enablement for upcoming and yet-to-be-released Intel and AMD CPUs and graphics hardware. While these updates will primarily benefit future hardware, several changes in this release directly impact today's users' day-to-day experience. The kernel now supports AMD's automatic Indirect Branch Restricted Speculation (IBRS) feature for Spectre mitigation, providing a less performance-intensive alternative to the retpoline speculative execution. Linux 6.3 also includes new power management drivers for ARM and RISC-V architectures. RISC-V has gained support for accelerated string functions via the Zbb bit manipulation extension, while ARM received support for scalable matrix extension 2 instructions. For filesystems, Linux 6.3 brings AES-SHA2-based encryption support for NFS, optimizations for EXT4 direct I/O performance, low-latency decompression for EROFS, and a faster Brtfs file-system driver. Bottom line: many file operations will be a bit more secure and faster. For gamers, the new kernel provides a native Steam Deck controller interface in HID. It also includes compatibility for the Logitech G923 Xbox edition racing wheel and improvements to the 8BitDo Pro 2 wired game controllers. Who says you can't game on Linux? Single-board computers, such as BannaPi R3, BPI-M2 Pro, and Orange Pi R1 Plus, also benefit from updated drivers in this release. There's also support for more Wi-Fi adapters and chipsets. These include: Realtek RTL8188EU Wi-Fi adapter support; Qualcomm Wi-Fi 7 wireless chipset support; and Ethernet support for NVIDIA BlueField 3 DPU. For users dealing with complex networks that have both old-school and modern networks, the new kernel can also handle multi-path TCP handling mixed flows with IPv4 and IPv6.' -- source: https://linux.slashdot.org/story/23/04/26/0023238 Cheers, Peter -- Peter Reutemann Dept. of Computer Science University of Waikato, Hamilton, NZ Mobile +64 22 190 2375 https://www.cs.waikato.ac.nz/~fracpete/ http://www.data-mining.co.nz/

1 0