[REVIEW][PATCH 1/2] userns: Better restrictions on when proc and sysfs can be mounted
Eric W. Biederman
ebiederm at xmission.com
Fri Nov 15 08:37:13 UTC 2013
Gao feng <gaofeng at cn.fujitsu.com> writes:
> Ok,I agree with you that we should make container security by default.
>
> What's your idea that introduces option MS_NOT_A_LOCK just like Andy's
> advisement?
It might be doable but it is unnecessary.
> In libvirt, host creates dev and devpts directories for container,then
> mount devpts, tmpfs on them and create device nodes inside these dirs
> for container. and then in container, these filesystems are moved to
> container's /dev/ /dev/pts directory. We really have no need to lock
> these mounts. they are just created for container.
If the global root creates the namespace and performs all of the mounts
it is unnecessary.
Now I believe you can create those directories for the most part as
non-root in libvirt and gain some interesting applications.
That said if you don't want locked mounts you just just be able to
create a temporary mount namespace as the global root, and do your prep
work.
Then create your unprivileged mount namespace and bind mount the
directories where you want them, and then pivot_root away the bits you
don't want.
There is already more mechanism than I like to deal with the mount
namespace I would really rather not invent/debug/support any more.
Eric
More information about the Containers
mailing list