Harden Dockerfile

[vittring]

Here we contain the running processes to non-root user to prevent mounting filesystems of host and protect against local privilege escalation (LPE).

• [x] Create non-root user and CHROOT

  RUN useradd --create-home --system --shell /bin/false $USER
  RUN mkdir --parents $WORKDIR
  RUN chown $USER:$USER --recursive $WORKDIR

• [x] Verify container image is running as venom

  docker ps --quiet | xargs docker inspect --format '{{ .Id }}: User={{ .Config.User }}'

[kattstof]

this ready to be merged i assume?

[vittring]

Yes, it's ready. I moved all the Docker stuff to a new directory to kind of clean up the tree a little. I've tested the image on Ubuntu 20.04 LTS and several Debian and Windows VMs, everything is working.