Stefan Berger writes: > On 07/13/2017 08:38 PM, Eric W. Biederman wrote: >> Stefan Berger writes: >> >>> On 07/13/2017 01:49 PM, Eric W. Biederman wrote: >>> >>>> My big question right now is can you implement Ted's suggested >>>> restriction. Only one security.foo or secuirty.foo@... attribute ? >>> We need to raw-list the xattrs and do the check before writing them. I am fairly sure this can be done. >>> >>> So now you want to allow security.foo and one security.foo@uid=<> or just a single one security.foo(@[[:print:]]*)? >>> >> The latter. > > That case would prevent a container user from overriding the xattr on > the host. Is that what we want? Most definitely. If a more privileged use has set secure.capable that is better. > For limiting the number of xattrs and > getting that functionality (override IMA signature for example) the > former seems better... I don't know about IMA. But my feeling is that we will only be dealing with a single signing key, so I don't see how having multiple IMA xattrs make sense. Could you explain that to me? > For the former I now have the topmost patch here: > https://github.com/stefanberger/linux/commits/xattr_for_userns.v3 Thank you. Eric