runc VS conmon

I can speak to this. Containers, and by extension k8s, break a well known security boundary that has existed for a very long time - whether you are using a real (hardware) server or a virtual machine on the cloud if you pop that instance/server generally speaking you only have access to that server. Yeh, you might find a db config with connection details if you landed on say a web app host but in general you still have to work to start popping the next N servers.

That's not the case when you are running in k8s and the last container breakout was just announced ~1 month ago: https://github.com/opencontainers/runc/security/advisories/G... .

At the end of the day it is simply not a security boundary. It can solve other problems but not security ones.

It's interesting that, in light of things like this, you still see large software companies adding support for new components written in non-memory safe languages (e.g. C)

As an example Red Hat OpenShift added support for crun(https://github.com/containers/crun) this year(https://cloud.redhat.com/blog/whats-new-in-red-hat-openshift...), which is written in C as an alternative to runc, which is written in Go(https://github.com/opencontainers/runc)...

Rabbit hole indeed. That wasn't related to my job at the time, lol. The job change came with a company-provided computer and that put an end to the tinkering.

BTW, I found my hacks to make runc run on Chromebook: https://github.com/opencontainers/runc/compare/main...gabrys...

being the main author of crun, I can clarify that statement: I am not a fan of Go _for this particular use case_.

Using C instead of Go avoided a bunch of the workarounds that exists in runc to workaround the Go runtime, e.g. https://github.com/opencontainers/runc/blob/main/libcontaine...

runc

Not OP, but if I had to guess, a lot of this can be picked up by just observing common security issues in the Linux space, since similar mistakes and oversights have caused quite a few real-world CVEs in the past, e.g. this random example of a TOCTTOU vulnerability in runc.

It is an open-source, community-driven project which supports OCI-based container registries. It is being maintained by contributors working in Red Hat, Intel, etc. It also comes with a monitoring program known as conmon. Conmon is an OCI container runtime monitor, which makes the communication between CRI-O and runc for a single container.

When considering using socket activation it's good to know that socket-activation has the advantage that you can create on-demand services. And in the future you might be able to do container image upgrades without loosing an active TCP connection https://github.com/containers/conmon/issues/393 (Right now it's just a feature request that I wrote).

This was a wrong assumption. Podman directly uses runC or crun instead of containerd using a technology named conmon. Some more useful information can be found in this article.

Well, "daemonless" is kind of marketing - there is still this daemon-per-container 'conmon' thing https://github.com/containers/conmon and I don't get why it is needed because 1) who actually needs to re-attach anyway? 2) container's streams are already properly handled by whatever supervisor (e.g. systemd). You can't disable conmon and I'm not sure if its usage is not hardcoded throughout the codebase.

I would very much like to use Podman as a finally proper container launcher in production (non-FAANG scale - at which you maybe start to need k8s), but having an unnecessary daemon moving part in thousands lines of C makes me frown so far.