Comment by pjc50 | Hacker News Reader

Comment by pjc50 | Hacker News Reader

Interesting. Basically the argument is as follows:

Conventional operating systems are multi-user: one user shares all their files with all their apps, but effort is put into protecting one user from another. This then gets breached all the time (escalation of privilege), and fails to capture the problem that attacks come from applications.

Unikernel/cloud systems are "zero-user": we have something that might be called a "process" in a traditional operating system, but instead of lots of fallible fine grained security boundaries we have only one, the hardware virtualization. The "process" runs directly below the hypervisor and interacts with "virtual hardware", predominantly with other networked services.

That raises the question - how is the hardware virtualization for these systems handled and secured? Do you get a virtual PCI bridge to a virtual network card?

> effort is put into protecting one user from another.

This is because it dates back to the times when you'd have multiple real users logged into a server on a campus. There's a bunch of *nix perms stuff that makes no sense in modern production environments.

And in my home environment, I only ever have one user and https://xkcd.com/1200/ is relevant.

> hardware virtualization

Is this similar with Qubes OS? https://qubes-os.org

You can think of this like Qubes but for the server-side instead of the desktop/consumer. It's a very good analogy in my opinion.

>zero-user

Wouldn't the normal "single user" term be more appropriate? Or by Zero user you mean something else?

I think 'zero user' is right, there just isn't any concept of users or permissions.

its really moving the classic OS resource sharing interface to the hypervisor. that's where the storage and network comes from. given that, what machinery do you need to run just one application? maybe a little filesystem, a tcp stack, interfaces to manipulate threads and kernel locks. that's what gets packaged up with your application into a bootable VM

So whoever exploits that one process has complete control over everything, right ?

Well, they have control over the application, and whatever its VM has access to .. which is supposed to be limited to only the things that the application needs.

Point raised in the TFA is that one process unikernal has a much smaller attack surface than a linux instance running the process would have.

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