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All Linux containers leak the host kernel no? The Anbox project relies on the exact same 2 modules: https://docs.anbox.io/userguide/install_kernel_modules.html

All Linux containers leak the host kernel no? The Anbox project relies on the exact same 2 modules: https://docs.anbox.io/userguide/install_kernel_modules.html https://docs.anbox.io/userguide/install_kernel_modules.html. While these are "android-specific", they are present in the linux kernel tree, and even come pre-installed in Ubuntu 19.04 (and probably more distros).

j4hdufd8 5y ago
> All Linux containers leak the host kernel no? Curious in what way?
- captn3m0 5y ago
  See any explanation of what a linux container is[0]. Containers in linux are a patchwork of various features that "contain" a process group in different ways while sharing the kernel with the rest of the system. Running either of docker run --rm --entrypoint /bin/uname alpine:latest -a or uname -a gives you the same kernel version. The only difference will be in the hostname. [0]: https://embeddedbits.org/introduction-linux-containers/ https://embeddedbits.org/introduction-linux-containers/
- IceWreck 5y ago
  That's the difference between a container and a VM. VM runs its own kernel. A container relies on the host kernel and the host machine's kernel does all the scheduling, memory management, etc.
- pmontra 5y ago
  See the other replies and if you're on Linux run ps -ef on the host and you'll see the processes in the containers too. That doesn't happen if those processes run in a VM.
  - mkdirp 5y ago
    This is by design. The kernel still runs the processes inside the container. If you namespace the user running `ps`, it will not be able to see the container processes. The only reason you're seeing them is because you're in the default (root?) namespace. The container on the other hand cannot see the host's processes or other things. At least not without an exploit.
NotEvil 5y ago
Not all linux kernel leak to host. Docker security is way better than nefore. And there also projects like podman and docker unprivileged that don't require any root intraction to set up a kernel
- captn3m0 5y ago
  Depends on your definition of "leak" I suppose. You can't get a different kernel version inside a container so there must be a "leak" in some sense. Reducing capabilities etc will just leak lesser information about the system in general, but your kernel is always shared.

j4hdufd8 5y ago

> All Linux containers leak the host kernel no? Curious in what way?

captn3m0 5y ago
See any explanation of what a linux container is[0]. Containers in linux are a patchwork of various features that "contain" a process group in different ways while sharing the kernel with the rest of the system. Running either of docker run --rm --entrypoint /bin/uname alpine:latest -a or uname -a gives you the same kernel version. The only difference will be in the hostname. [0]: https://embeddedbits.org/introduction-linux-containers/ https://embeddedbits.org/introduction-linux-containers/
IceWreck 5y ago
That's the difference between a container and a VM. VM runs its own kernel. A container relies on the host kernel and the host machine's kernel does all the scheduling, memory management, etc.
pmontra 5y ago
See the other replies and if you're on Linux run ps -ef on the host and you'll see the processes in the containers too. That doesn't happen if those processes run in a VM.
- mkdirp 5y ago
  This is by design. The kernel still runs the processes inside the container. If you namespace the user running `ps`, it will not be able to see the container processes. The only reason you're seeing them is because you're in the default (root?) namespace. The container on the other hand cannot see the host's processes or other things. At least not without an exploit.

NotEvil 5y ago

Not all linux kernel leak to host. Docker security is way better than nefore. And there also projects like podman and docker unprivileged that don't require any root intraction to set up a kernel

captn3m0 5y ago
Depends on your definition of "leak" I suppose. You can't get a different kernel version inside a container so there must be a "leak" in some sense. Reducing capabilities etc will just leak lesser information about the system in general, but your kernel is always shared.