Re: [PATCH v2] xattr: Enable security.capability in user namespaces

[Mimi Zohar]

On Tue, 2017-07-25 at 22:00 -0500, Serge E. Hallyn wrote:
> On Fri, Jul 14, 2017 at 03:26:14PM -0400, Mimi Zohar wrote:
> > On Fri, 2017-07-14 at 13:17 -0500, Eric W. Biederman wrote:
> > > Which brings us to the semantic question of would it be nice to have
> > > stacked IMA/EVM on the same file.
> > > 
> > > I really don't think we do.  I think allowing multiple keys for
> > > different part of trusting files is easy enough that we should have no
> > > need to fight over which keys do which.
> > 
> > We definitely want to support different policies on the native and in
> > the namespace with different keys and keyrings.
> 
> Ok, so Stefan's code to support userspace in a container reading
> security.ima and getting back the value for security.ima@uid=1000
> (if 1000 is the kuid of the container's root user) is in fact
> useful to IMA?

Definitely! ÂRoot within the namespace needs to be able to read and
write security.ima in order to (re)sign files, with a specific key
known to that container. ÂStefan's code provides different views of
the security xattrs.

Mimi