Re: Creating tasks on restart: userspace vs kernel

[Serge E. Hallyn]

Quoting Oren Laadan (orenl@xxxxxxxxxxxxxxx):
> For #1, we need to create a new container to begin with. This already
> requires CAP_SYS_ADMIN. Yes, for now we can use some setuid() to create
> a new pid_ns and then do the restart.

This is why I like tagging a pidns with a userid, and requiring that
current->euid==pidns->uid in order to be allowed to set pid in that
pidns.

We require cap_sys_admin wil doing clone(CLONE_NEWPID).  So if we do
that while uid=500, then drop cap_sys_admin, then we can proceed to
create new tasks with specified pids in that pidns.

-serge
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