Note that your server will almost definitely hang, requiring a physical (or IPMI) reboot, because no interrupts, including NMIs, can be delivered to the zombie cores: this means no scheduler, no IPIs, nothing will work.

source: HN

The carrot basically is: if you have a well-behaved feed reader, you will continue to be able to discover a new post on my feed in a reasonable amount of time. This is most people. Most people do it right. Thank you for that.

The stick is: if you do not, you will not. It will take considerably longer to notice something’s different out here.

Most people who deal with X resources, me included, generally deal with them at a relatively superficial level. At this level, you can say that X resources are a text based key/value database, with the name (key) of every resource being a composite name that specifies both its program and some program specific name (although there are conventions for the name portion). But if you start to look at the actual names for X resources, things start looking a little more odd.

Into the rabbit hole.

Also: https://utcc.utoronto.ca/~cks/space/blog/unix/XResourcesFailure

One of the problems with X resources is that they’re arcane and hard to manage.

I’ve written about SNI proxying before, but in a nutshell: a proxy server can use the first message in a TLS connection (the Client Hello message, which is unencrypted and contains the server name (SNI) that the client wants to connect to) to decide where to route the connection.

source: L

For a couple hundred lines of code (not counting the entire user-mode Linux you’ll be pulling in from gVisor, HEY! Dependencies! What are you gonna do!) you can bring up a new, cryptographically authenticated network, any time you want to, in practically any program.

There really are some fun libraries out there if you want to build something crazy.

source: HN

Some useful config options showing off flexibility beyond the basics.

source: Dfly

The simple thing to say about this is that it only happens on Ubuntu 16.04, not on 18.04 or 20.04, and it happens because Ubuntu’s normal /etc/bash.bashrc defines a command_not_found_handle function that winds up running a helper program to produce this ‘did you mean’ report. The helper program comes from the command-not-found package, which is installed because it’s Recommended by ubuntu-standard.

This is part 1 of a 6-part series detailing a set of vulnerabilities found by Project Zero being exploited in the wild.

At Project Zero we often refer to our goal simply as “make 0-day hard”. Members of the team approach this challenge mainly through the lens of offensive security research. And while we experiment a lot with new targets and methodologies in order to remain at the forefront of the field, it is important that the team doesn’t stray too far from the current state of the art. One of our efforts in this regard is the tracking of publicly known cases of zero-day vulnerabilities. We use this information to guide the research. Unfortunately, public 0-day reports rarely include captured exploits, which could provide invaluable insight into exploitation techniques and design decisions made by real-world attackers. In addition, we believe there to be a gap in the security community’s ability to detect 0-day exploits.

Chrome: Infinity Bug - https://googleprojectzero.blogspot.com/2021/01/in-wild-series-chrome-infinity-bug.html

Chrome Exploits - https://googleprojectzero.blogspot.com/2021/01/in-wild-series-chrome-exploits.html

Android Exploits - https://googleprojectzero.blogspot.com/2021/01/in-wild-series-android-exploits.html

Android Post-Exploitation - https://googleprojectzero.blogspot.com/2021/01/in-wild-series-android-post-exploitation.html

Windows Exploits - https://googleprojectzero.blogspot.com/2021/01/in-wild-series-windows-exploits.html

This post is about the situation with Domain Keys Identified Mail (DKIM), a harmless little spam protocol that has somehow become a monster. My request is simple and can be summarized as follows: Dear Google: would you mind rotating and publishing your DKIM secret keys on a periodic basis? This would make the entire Internet quite a bit more secure, by removing a strong incentive for criminals to steal and leak emails. The fix would cost you basically nothing, and would remove a powerful tool from hands of thieves.

source: green

Python can execute code. Make sure it executes only the code you want it to.

Not exclusive to python either.

source: L

Obviously, to do stuff like this, you need to generate certificates. The reasonable way to do that in 2020 is with LetsEncrypt. We do that for our users automatically, but “it just works” makes for a pretty boring writeup, so let’s see how complicated and meandering I can make this.

It’s time to talk about certificate infrastructure.

source: L

Those who know me know that I am a bit fan of the oldschool Lenovo ThinkPad laptops with real 7-row keyboards. I own several *20 models from 2011 including W520, T420s and X220 ones. They still rock when it comes to ‘laptop computing’ and they are dirt cheap on any auction platform. They only got one flaw … that thermal compound on CPU (and sometimes GPU) gets older a lot faster then these laptops.

source: vermaden

This is fun and all, but we can’t really talk about security only with chroot, and the Firecracker solution seemed about right for this matter, yet the overall NetBSD boot process was a bit too long for my taste. So how exactly can we significantly improve NetBSD‘s boot speed?

source: L

A lot of stuff on the Internet is currently broken on account of a Sectigo root certificate expiring at 10:48:38 UTC today. Generally speaking, this is affecting older, non-browser clients (notably OpenSSL 1.0.x) which talk to TLS servers which serve a Sectigo certificate chain ending in the expired certificate. See also this Twitter thread by Ryan Sleevi.

https://twitter.com/sleevi_/status/1266647545675210753

source: HN

We exhaustively tested ZFS and RAID performance on our Storage Hot Rod server.

source: ars

10 years ago, systemd was announced and swiftly rose to become one of the most persistently controversial and polarizing pieces of software in recent history, and especially in the GNU/Linux world. The quality and nature of debate has not improved in the least from the major flame wars around 2012-2014, and systemd still remains poorly understood and understudied from both a technical and social level despite paradoxically having disproportionate levels of attention focused on it.

I am writing this essay both for my own solace, so I can finally lay it to rest, but also with the hopes that my analysis can provide some context to what has been a decade-long farce, and not, as in Benno Rice’s now famous characterization, tragedy.

source: grugq

But I wasn’t interested in fixing it, I wanted to know why it happens. So why does strace not work, and why does --cap-add=SYS_PTRACE fix it?

source: HN

Since this dates from early 2018, I believe it’s in everything from OpenBSD 6.4 onward. It’s definitely in OpenBSD 6.6. This new CPU time category is supported in OpenBSD’s versions of top and systat, but it is not explicitly broken out by vmstat; in fact vmstat’s ‘sy’ time is actually the sum of OpenBSD ‘system’, ‘interrupt’, and ‘spinning’. Third party tools may or may not have been updated to add this new category.

oxbar is a X11 status bar for OpenBSD showing various system stats. It has a configurable display and works out-of-the-box on most modern window managers in an intuitive fashion. oxbar supports FreeType font rendering and styling, true transparency & alpha blending on all UI components (including the root window), and a simple configuration format that can concisely support multiple themes.

source: vermaden

The goal for my infrastructure is to run the services I need. While a lot of people in the homelab community experiment and play with software for its own sake, I actively use the stuff I host. When I stop, I kill the service (though I’m not as proficient at this as Google). These are my production systems, and when one of them is down, I do miss it.

source: vermaden