Re: [PATCH] [RFC] mnt: add ability to clone mntns starting with the current root

[Al Viro]

On Tue, Oct 07, 2014 at 04:12:57PM +0400, Andrey Vagin wrote:
> Another problem is that rootfs can't be hidden from a container, because
> rootfs can't be moved or umounted.

... which is a bug in mntns_install(), AFAICS.

> Here is an example how to get access to rootfs:
> fd = open("/proc/self/ns/mnt", O_RDONLY)
> umount2("/", MNT_DETACH);
> setns(fd, CLONE_NEWNS)
> 
> rootfs may contain data, which should not be avaliable in CT-s.

Indeed.

> I suggest to add ability to create a mount namespace with specified
> mount points. A current task root can be used as a root for the new
> mount namespace.

Yecchh...  Frankly, you are opening a big can of worms - having rootfs
as absolute root of all namespaces simplifies a lot of things in there.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/