May 2024 - wlug - list.wlug.org.nz

New Attack On AI Bots: Prompt Injection
by Lawrence D'Oliveiro 01 Jul '26

01 Jul '26

A Twitter bot account run by a company that posts remote job listings was programmed to respond to tweets directed to it with general inoffensive comments touting the positive aspects of remote work. However <https://arstechnica.com/information-technology/2022/09/twitter-pranksters-d…>, some other Twitter users discovered that if they began their tweet with directives to “ignore previous instructions”, they could get the bot to say just about anything. And much hilarity ensued. Basically, the way the bot program works is it begins with some standard instructions on what to say, provided by the people who set up the account, to which is appended whatever tweet content was sent to the bot by the other user. This is then processed by the AI system to produce a response. This attack has been dubbed “prompt injection”, by analogy with “SQL injection” and other similar attacks on non-AI systems. But whereas those attacks can be blocked using basic, well-known syntactic quoting techniques, there seem to be no easy equivalents for stopping an AI paying attention to instructions it should not be obeying.

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Weta Digital’s Technology Division Sold To US Firm
by Lawrence D'Oliveiro 01 Aug '25

01 Aug '25

Let me see if I understand this article <https://www.nzherald.co.nz/business/sir-peter-jackson-to-sell-weta-digital-…> correctly: the part of Weta Digital that used to develop the in-house 3D graphics/effects tools that they use in all those movies is being sold to US-based Unity Software. The part that is left will be called “WetaFX”, and will become a customer of Unity for the use of those tools, no longer doing its own development in-house. By the way, I’ve been looking at the Unity site <https://unity.com/>, and it looks like all their products are rentware (subscription-based).

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New systemd update will bring Windows’ infamous Blue Screen of Death to Linux
by Peter Reutemann 18 Nov '24

18 Nov '24

'Windows' infamous "Blue Screen of Death" is a bit of a punchline. People have made a hobby of spotting them out in the wild, and in some circles, they remain a byword for the supposed flakiness and instability of PCs. To this day, networked PCs in macOS are represented by beige CRT monitors displaying a BSOD. But the BSOD is supposed to be a diagnostic tool, an informational screen that technicians can use to begin homing in on the problem that caused the crash in the first place; that old Windows' BSOD error codes were often so broad and vague as to be useless doesn't make the idea a bad one. Today, version 255 of the Linux systemd project honors that original intent by adding a systemd-bsod component that generates a full-screen display of some error messages when a Linux system crashes. The systemd-bsod component is currently listed as "experimental" and "subject to change." But the functionality is simple: any logged error message that reaches the LOG_EMERG level will be displayed full-screen to allow people to take a photo or write it down. Phoronix reports that, as with BSODs in modern Windows, the Linux version will also generate a QR code to make it easier to look up information on your phone.' -- source: https://arstechnica.com/gadgets/2023/12/linux-distros-are-about-to-get-a-ki… 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/

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Juice TV Hiccup
by Lawrence D'Oliveiro 15 Oct '24

15 Oct '24

Currently when I switch to FreeView Channel 200, it shows a frozen image with the text “Cinegy” and “Demo Version” on it. Searching for that name takes me to a site that talks about “software defined television”. Either their product licence has expired, or they never had one in the first place ...

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List Of IPTV Resources
by Lawrence D'Oliveiro 22 Sep '24

22 Sep '24

This user <https://github.com/iptv-org> just popped up in my GitHub feed. One repo <https://github.com/iptv-org/iptv> claims to be a list of links to over 8000 streaming TV channels from nations all over the world, while the other is a list of tools*, providers and other resources. Do be aware it’s a bit of a mixed bag: yes, there are legitimate channels (no encryption so far that I have noticed), but also some dubious-looking links. *Oddly, FFmpeg and youtube-dl aren’t in the list.

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Made Move To Wayland
by Lawrence D'Oliveiro 01 Jul '24

01 Jul '24

I’d been running Wayland OK on my laptop for some months now, but I held off putting it on my main machine for one reason: when I logged into a Wayland session, Emacs would not recognize my Compose key (which I have set to Caps Lock). Today I finally figured out I have to install the “emacs-pgtk” package instead of “emacs-gtk”; the former is built with a version of GTK that works with Wayland. And yes, my Compose key works again. Still have to get used to slightly different input behaviour: previously, once I hit Compose, nothing would appear until I finished the whole key sequence. Now it echoes each keystroke immediately as I type it, in place, overwriting the previous echo (starting with an underline for the Compose key itself), then when I have typed the last key, it overwrites the echo area with the final character.

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Fun With The du Command
by Lawrence D'Oliveiro 29 May '24

29 May '24

Looking at the space taken up by my copy of the Blender source code: ldo(a)theon:projects> du -ks blender 1444272 blender Most of that is in the commit history: ldo(a)theon:projects> du -ks blender/.git 1139640 blender/.git So how much isn’t? ldo(a)theon:projects> du -ks blender/.git blender 1139640 blender/.git 304632 blender Do you see what happened there? If you specify a directory, and then its containing directory on the same command, du will subtract the usage of the former from the latter. This gives you an easy way of determining the space taken up by a directory, not including particular subdirectories. This can be broken down even more: ldo(a)theon:projects> du -ks blender/.git blender/extern blender/intern blender/source blender 1139640 blender/.git 40536 blender/extern 15712 blender/intern 105188 blender/source 143196 blender Here, “extern” is various open-source libraries from other sources, that have been copied into the Blender source tree, while “intern” is code that originated from Blender itself, that has been organized into its own libraries. And as you can see, there is still a whole bunch left in other subdirectories. Does this work recursively? ldo(a)theon:projects> du -ks blender/.git blender/intern/cycles blender/intern blender 1139640 blender/.git 8880 blender/intern/cycles 6832 blender/intern 288920 blender Yes it does. Here we can see that the Cycles renderer makes up a bit over half the contents of “intern”.

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datamash - basic numeric, textual and statistical operations
by Peter Reutemann 28 May '24

28 May '24

Hi everyone I quite often need to do some quick and dirty statistical calculations on the command-line and I typically use cat and sed to extract the data that I need from text files. In the past, I've then switched to LibreOffice Calc for some basic statistics like mean/stdev. Today, I finally spent a bit more time having a look around what else I can use directly on the command-line and came across the following that fits the bill perfectly: datamash - https://www.gnu.org/software/datamash/ With that tool, I can finally apply a single command-line to textual output for generating a quick mean/stdev: ... | datamash mean 1 sstdev 1 --header-out mean(field-1) sstdev(field-1) 577.62815533981 128.99238940453 Cheers, Peter

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Memory Sealing 'mseal' System Call Merged For Linux 6.10
by Peter Reutemann 27 May '24

27 May '24

'"Merged this Friday evening into the Linux 6.10 kernel is the new mseal() system call for memory sealing," reports Phoronix: The mseal system call was led by Jeff Xu of Google's Chrome team. The goal with memory sealing is to also protect the memory mapping itself against modification. The new mseal Linux documentation explains: "Modern CPUs support memory permissions such as RW and NX bits. The memory permission feature improves security stance on memory corruption bugs, i.e. the attacker can't just write to arbitrary memory and point the code to it, the memory has to be marked with X bit, or else an exception will happen. Memory sealing additionally protects the mapping itself against modifications. This is useful to mitigate memory corruption issues where a corrupted pointer is passed to a memory management system... Memory sealing can automatically be applied by the runtime loader to seal .text and .rodata pages and applications can additionally seal security-critical data at runtime. A similar feature already exists in the XNU kernel with the VM_FLAGS_PERMANENT flag and on OpenBSD with the mimmutable syscall." The mseal system call is designed to be used by the likes of the GNU C Library "glibc" while loading ELF executables to seal non-writable memory segments or by the Google Chrome web browser and other browsers for protecting security sensitive data structures.' -- source: https://linux.slashdot.org/story/24/05/26/2117251 Cheers, Peter

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Ubuntu 24.04 Now Runs on the Nintendo Switch (Unofficially)
by Peter Reutemann 27 May '24

27 May '24

'"The fact it's possible at all is a credit to the ingenuity of the open-source community," writes the blog OMG Ubuntu: Switchroot is an open-source project that allows Android and Linux-based distros like Ubuntu to run on the Nintendo Switch — absolutely not something Nintendo approves of much less supports, endorses, or encourages, etc! I covered the loophole that made this possible back in 2018. Back then the NVIDIA Tegra X1-powered Nintendo Switch was still new and Linux support for much of the console's internal hardware in a formative state (a polite way to say 'not everything worked'). But as the popularity of Nintendo's handheld console ballooned (to understate it) so the 'alternative OS' Switch scene grew, and before long Linux support for Switch hardware was in full bloom... A number of Linux for Switchroot (L4S) distributions have since been released, designated as Linux for Tegra (L4T) builds. As these can boot from a microSD card it's even possible to dualboot the Switch OS with Linux, which is neat! Recently, a fresh set of L4T Ubuntu images were released based on the newest Ubuntu 24.04 LTS release. These builds work on all Switch versions, from the OG (exploit-friendly) unit through to newer, patched models (where a modchip is required)... I'm told all of the Nintendo Switch internal hardware now works under Linux, including Wi-Fi, Bluetooth, sleep mode, accelerated graphics, the official dock... Everything, basically. And despite being a 7 year old ARM device the performance is said to remain decent. "Upstream snafus have delayed the release of builds with GNOME Shell..."' -- source: https://games.slashdot.org/story/24/05/26/035202 Cheers, Peter

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