Re: [RFC][PATCH 0/9] Make containers kernel objects

[Colin Walters]

On Tue, May 23, 2017, at 10:30 AM, Djalal Harouni wrote:
>
> Maybe it depends on the cases, a general approach can be too difficult
> to handle especially from the security point. Maybe it is better to
> identify what operations need what context, and a userspace
> service/proxy can act using kthreadd with the right context... at
> least the shift to this model has been done for years now in the
> mobile industry.

Why not drop the upcall model in favor of having userspace
monitor events via a (more efficient) protocol and react to them on its own?
It's just generally more flexible and avoids all of those issues like
replicating the seccomp configuration, etc.

Something like inotify/signalfd could be a precedent around having a read()/poll()able
fd.  /proc/keys-requests ?

Then if you create a new user namespace, and open /proc/keys-requests, the
kernel will always write to that instead of calling /sbin/request-key.