Linux kernel security work

[coppsilgold]

Recently, things have been advancing which may finally allow a seamless virtualization experience on the Linux desktop (and match QubesOS in some security aspects).

GPU drivers supporting native contexts with Mesa support.

Wayland sharing between guest and host. It used to be somewhat sloppy (involved protocol parsing; sommilier & wayland-proxy-virtwl) but recently someone undertook a project to do it properly that may soon bear fruit: https://codeberg.org/drakulix/wl-cross-domain-proxy

A VMM to utilize these features: https://github.com/AsahiLinux/muvm

And a solution which ties these things together: https://git.clan.lol/clan/munix

[conradev]

This is really cool!

I wonder if it would be possible to live-migrate apps from one machine running munix to another. You could pause, transfer, and resume the virtual machine.

[tuananh]

this is why redhat is still relevant in 2025. there's always a need for this kind of work.

[staticassertion]

I think you could make a stronger case for the opposite. How does Redhat know which commits to cherry when upstream explicitly won't tell you which are relevant to security?

[DebugDruid]

Sometimes I dream about a 100% secure OS. Maybe formal verification is the key, or Rust, I don’t know. But I would love to know that I can't be hacked.

[themafia]

> But I would love to know that I can't be hacked.

Cool. So social engineering it is. You are your own worst enemy anyways.

[jeffbee]

The problem is that for the overwhelming majority of use cases the isolation features that are violated by security bugs are not being used for real isolation, but for manageability and convenience. Virtualization, physical host segregation, etc are used to achieve greater isolation. People don't necessarily care about these flaws because they aren't actually exposed to the worst case preconditions. So the amount of contributor attention you could get behind a "100% secure OS" might not be as large as you are hoping. Anyway if you want to work on such things there are various OS development efforts floating around.

[pjmlp]

This has been done multiple times in research, see Verve OS from Microsoft, even Assembly is verified, that is where Dafny came from.

https://en.wikipedia.org/wiki/Verve_(operating_system)

However, worse is better on the market, and quality doesn't pay off, hence why such ideas take decades into mainstream.

[fsflover]

Here you go: https://qubes-os.org

[sydbarrett74]

Anything made by humans can be unmade by humans. Security is a perpetual arms race.

[staticassertion]

"A bug is a bug" lol.

There's a massive difference between "DoS requiring root" and "I can own you from an unprivileged user with one system call". You can say "but that DoS could have been a privesc! We don't know!" but no one is arguing otherwise? The point is that we do know the impact of some bugs is strictly a superset of other bugs, and when those bugs give control or allow a violation of a defined security boundary, those are security bugs.

This has all been explained to Greg for decades, nothing will change so it's just best to accept the state - I'm glad it's been documented clearly.

Know this - your kernel is not patched unless you run the absolute latest version. CVEs are discouraged, vuln fixes are obfuscated, and you should operate under that knowledge.

Attackers know how to watch the commit log for these hidden fixes btw, it's not that hard.

edit: Years later and I'm still rate limited so I can't reply. @dang can this be fixed? I was rate limited for posting about Go like... years ago.

To the person who replies to me:

> This is correct for a lot of different software, probably most of it. Why is this a point that needs to be made?

That's not true at all. You can know if you're patched for any software that discloses vulnerabilities by checking if your release is up to date. That is not true of Linux, by policy, hence this entire post by Greg and the talks he's given about suggesting you run rolling releases.

Sorry but it's too annoying to reply further with this rate limiting, so I'll be unable to defend my points.

[tamirzb]

> Know this - your kernel is not patched unless you run the absolute latest version.

This is correct for a lot of different software, probably most of it. Why is this a point that needs to be made?

[anonnon]

Meanwhile it's 2026 and Greg's own website still doesn't support TLS.

[juliangmp]

Honestly, until encrypted client hello has widespread support, why bother? I mean I did it for fun the first time and now with caddy its not a lot of effort. But for a personal blog, a completely static site, what benefit do you get from the encryption? Anyone monitoring the traffic will see the domain in clear text anyway. And they'd see the destination IP, which I imagine in this case being one server that has exactly one domain pointed at it.

[miduil]

> If you are forced to use encryption to report security problems, please reconsider this policy as it feels counterproductive (UK government, this means you…)

LOL

[tuananh]

if they really think that, they should have remove their CNA, no?

[theamk]

Nah, "removing CNA" = "let any security researcher decide what kernel vulnerability is"

And unfortunately, there are plenty of security researchers who are only interested in personal CVE counts, and will try to assign highest priority to a mostly harmless bug.

[cogman10]

Why? What benefit would https provide over http when visiting a pure information (and I'm guessing statically generated) website?

[vlovich123]

I think the most practical reason not to flag which bugs are security bugs is to avoid helping blackhat hackers by painting a giant neon sign and that should be more than enough.

I think all the other explanations are just double-think. Why? If "bugs are just bugs" is really a true sentiment, why is there a separate disclosure process for security bugs? What does it even mean to classify a bug as a security bug during reporting if it's no different than any other bug report? Why are fixes developed in secret & potential embargoes sometimes invoked? I guess some bugs are more equal than others?

[fguerraz]

As mentioned in the article, every bug is potentially a security problem to someone.

If you know that something is a security issue to your organization, you definitely don't want to paint a target on your back by reporting the bug publicly with an email address <your_name>@<your_org>.com. In the end, it is really actually quite rare (given the size of the code base and the popularity of linux) that a bug has a very wide security impact.

The vast majority of security issues don't affect organizations that are serious about security (yes really, SELinux eliminates or seriously reduces the impact of the vast majority of security bugs).

[staticassertion]

> I think the most practical reason not to flag which bugs are security bugs is to avoid helping blackhat hackers by painting a giant neon sign and that should be more than enough.

It doesn't work. I've looked at the kernel commit log and found vulnerabilities that aren't announced/ marked. Attackers know how to do this. Not announcing is a pure negative.

[badgersnake]

And then all our customers will demand fixes for them in our docker images, because they’re that smart.

There must be a way to ship a docker image without a kernel, since it doesn’t get used for anything anyway.

[derkades]

Huh, how do you unintentionally ship a Linux kernel in a container image? The common base images definitely don't contain the kernel.

[shepherdjerred]

https://github.com/wolfi-dev

[JCattheATM]

Their view that security bugs are just normal bugs remains very immature and damaging. It it somewhat mitigated by Linux having so many eyes on it and so many developers, but a lot of problems in the past could have bee avoided if they adopted the stance the rest of the industry recognizes as correct.

[tptacek]

From their perspective, on their project, with the constraints they operate under, bugs are just bugs. You're free to operationalize some other taxonomy of bugs in your organization; I certainly wouldn't run with "bugs are just bugs" in mine (security bugs are distinctive in that they're paired implicitly with adversaries).

To complicate matters further, it's not as if you could rely on any more "sophisticated" taxonomy from the Linux kernel team, because they're not the originators of most Linux kernel security findings, and not all the actual originators are benevolent.

[jacobsenscott]

Classifying bugs as security bugs is just theater - and any company or organization that tries to classify bugs that way is immature and hasn't put any thought into it.

First of all "security" is undefined. Second, nearly every bug can be be exploited in a malicious way, but that way is usually not easy to find. So should every bug be classified as a security bug?

Or should only bugs where a person can think of a way on the spot during triage to exploit that bug as a security bug? In that case only a small subset of your "security" bugs are classified as such.

It is meaningless in all cases.

[schmuckonwheels]

Linus has been very clear on avoiding the opposite, which is the OpenBSD situation: they obsess about security so much that nothing else matters to them, which is how you end up with a mature 30 year old OS that still has a dogshit unreliable filesystem in 2026.

To paraphrase LT, security bugs are important, but so are all the other bugs.

[akerl_]

This feels almost too obvious to be worth saying, but “the rest of the industry” does not in fact have a uniform shared stance on this.

[firesteelrain]

“A bug is a bug” is about communication and prioritization, not ignoring security. Greg’s post spells that out pretty clearly.

[redleader55]

The rest of the industry relies on following a CVE list and ticking off vulnerabilities as a way to ensure "owners" are correctly assigned risk and sign it off - because there is nothing else that "owners" could do. The whole security through CVE is broken and is designed to be useful to create large "security organizations" that have the single purpose of annoying everyone with reports without solving any issues.

[themafia]

> a lot of problems in the past could have bee avoided

Such as?

[beanjuiceII]

did you read it? because that's not their view at all