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Dirty Frag: Universal Linux LPE

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Re: Dirty Frag: Universal Linux LPE

#271
post #262

Earlier quoted context omitted.

That is a well know and entirely different issue

Is it? The claim is Android is much more secure than other Linux, but if 40% of all Android devices don‘t get a security patch and you can’t even do it yourself I would call the more secure per se. Hardening is one part of security, patchability another. Android lacks in the latter.

>if 40% of all Android devices don‘t get a security patch

No system will stay secure once it does not receive updates. That does not exclude it from being more secure than another system based on security feature merits as long as it does get updated.

>Hardening is one part of security, patchability another. Android lacks in the latter.

That is not an inherent flaw with android but OEM devices shipping modified android they don't bother keeping up to date. Some OEMs are trying to mitigate this by increasing security update support up to 7 years which still is not long enough but also doesn't make them less secure than a desktop that gets updated longer.

What people forget is that not only desktop and mobile phone software is different but also the hardware. If your desktop pc hardware is out of date / EOL nobody cares usually. Meanwhile on a phone this can be a lot more relevant because security expectations and threat models are a lot higher, for example see all the zero/one click compromise headlines.

Re: Dirty Frag: Universal Linux LPE

#272

Earlier quoted context omitted.

Distro maintainers blacklisting specific functionality because they believe YAGNI is a pretty big ask. They just don't know who is using what. It's always possible for users to go back and tailor their builds for the stuff they actually want. And... I remember the early days of Linux where I ran `make menuconfig` and selected exactly the functionality I wanted in my kernel. I'd... rather not end up back there. That s…

Don't disagree, but there are eBPF mitigations that work as alternatives to unloading kernel modules.

Can you elaborate on that?

Re: Dirty Frag: Universal Linux LPE

#273
post #262

Earlier quoted context omitted.

That is a well know and entirely different issue

Is it? The claim is Android is much more secure than other Linux, but if 40% of all Android devices don‘t get a security patch and you can’t even do it yourself I would call the more secure per se. Hardening is one part of security, patchability another. Android lacks in the latter.

So what? Most devices running Linux don't get security patched, it was ever thus. Think about all the kernels running in wifi routers and other embedded devices.

Re: Dirty Frag: Universal Linux LPE

#275
post #7

Earlier quoted context omitted.

Android has a lot of hardening and sandboxing that desktop Linux doesn't (and won't for UX reasons).

> desktop Linux doesn't (and won't for UX reasons) Can you elaborate?

Locking down a desktop OS to modern standards really requires what Apple did with macOS, which requires a degree of central coordination that's beyond the Linux community. It mandates huge changes in almost every area of the OS stack, and all apps have to be sandboxed by default out of the box.

Developers don't like mandatory sandboxing. It has to be forced on them. So you can see the difficulty of doing it in the open source community, which has for decades now had the worst security of any desktop OS platform (even Windows is better).

Re: Dirty Frag: Universal Linux LPE

#276

Earlier quoted context omitted.

> desktop Linux doesn't (and won't for UX reasons) Can you elaborate?

To solve the issue from the source, you need to enforce security through means like mandatory access control. The problem is that existing desktop and server systems are too mature for that to be practical, you'll have to rework almost everything and users will certainly reject it violently due to the breakages.

Apple have shown it can be done with macOS. Not only is every app sandboxed in a usefully robust way (even ones distributed outside the app store) but this has been done in a way smooth enough that users didn't revolt.

Re: Dirty Frag: Universal Linux LPE

#277
post #236
post #55

Earlier quoted context omitted.

https://www.androidpolice.com/google-support-linux-kernels-a... Google relies on Linux LTS kernels. When the Linux LTS team dropped support from 6 years down to 2 years, Google stepped in to cover the 4-year gap. It is Linux. It's basically a distro.

When people say Linux they mean GNU/Linux.

Alpine Linux is not using GNU. I'm sure there are others. No definition you can ever come up with will have no exceptions in widespread use. Live with it.

Re: Dirty Frag: Universal Linux LPE

#278
post #66

Every time someone finds a universal Linux privilege escalation, somewhere a sysadmin whispers 'this is why we don't run as root' while nervously checking if their containers are actually isolated.

This attack class lets you escalate from any user to UID 0. Not running as root won't save you, in fact, this attack is for those processes not running as root. However, if you are in a user namespace where UID 0 doesn't map to system-wide capabilities, and you dont share page cache for the setuid binaries on the system, this attack doesn't lead to LPE.

setuid binaries are not the only way to get root. E.g. one can change /etc/crontab or /etc/passwd. Or add trojan to /bin/ls and wait until admin type 'ls'

Re: Dirty Frag: Universal Linux LPE

#279

Earlier quoted context omitted.

This is really not a correct statement beyond the fact that both are a type of Unix.

Linux is not Unix: it is not derived from AT&T Unix.

By that definition, nor is BSD. It's kind of their whole raison d'étre.
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