Re: [PATCH] [RFC] c/r: Add UTS support

[Dan Smith <danms-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>]

SH> Well it forces restart to go through the established userspace
SH> API's when creating resources (in this case, tasks and namespaces)
SH> which means any existing security guarantees are leveraged.

That's a very valid point.  However, it still seems unbalanced to make
checkpoint a completely in-kernel process and restart an odd mix of
the two with potentially more confusing semantics and requirements.

SH> If we go with your patch, we suddenly have to worry about whether
SH> restart is a way to get around the CAP_SYS_ADMIN requirements for
SH> cloning a new namespace.  Just as an example.

Why?  The call to copy_namespaces() will do the CAP_SYS_ADMIN check,
right?  Maybe your point is that in the restart implementation of
other namespace types we could potentially slide in a call to
something else that has already assumed the check has been made?  I
think that doing the obligatory copy_namespaces() during the restart
helps catch that case early and explicitly, no?

-- 
Dan Smith
IBM Linux Technology Center
email: danms-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org