Re: [PATCHv3 0/2] capability controlled user-namespaces

On Mon, Jan 08, 2018 at 11:35:26AM +1100, James Morris wrote:

On Tue, 2 Jan 2018, Mahesh Bandewar (महेश बंडेवार) wrote:

quoted

On Sat, Dec 30, 2017 at 12:31 AM, James Morris
[off-list ref] wrote:

quoted

On Wed, 27 Dec 2017, Mahesh Bandewar (महेश बंडेवार) wrote:

quoted

Hello James,

Seems like I missed your name to be added into the review of this
patch series. Would you be willing be pull this into the security
tree? Serge Hallyn has already ACKed it.

Sure!

Thank you James.

I'd like to see what Eric Biederman thinks of this.

Also, why do we need the concept of a controlled user-ns at all, if the 
default whitelist maintains existing behavior?

In past discussions two uses have been brought up:

1. if an 0-day is discovered which is exacerbated by a specific
privilege in user namespaces, that privilege could be turned off until a
reboot with a fixed kernel is scheduled, without fully disabling all
containers.

2. some systems may be specifically designed to run software which
only requires a few capabilities in a userns.  In that case all others
could be disabled.