On Tue, Mar 06, 2018 at 10:33:17PM +0000, Andy Lutomirski wrote:

quoted

quoted

Suppose I'm writing a container manager.  I want to run "mount" in the
container, but I don't want to allow moun() in general and I want to
emulate certain mount() actions.  I can write a filter that catches
mount using seccomp and calls out to the container manager for help.
This isn't theoretical -- Tycho wants *exactly* this use case to be
supported.

Well, I think this use case should be handled with something like
LD_PRELOAD and a helper library. FYI, I did something like this:
https://github.com/stemjail/stemshim

I doubt that will work for containers.  Containers that use user
namespaces and, for example, setuid programs aren't going to honor
LD_PRELOAD.

Or anything that calls syscalls directly, like go programs.

Tycho