On Mon, 1 Oct 2018, Darrick J. Wong wrote: > If we /did/ replace CAP_SYS_ADMIN checking with a pile of LSM hooks, Not sure we'd need a pile of hooks, what about just "read" and "write" storage admin? Or even two new capabilities along these lines, which we convert existing CAP_SYS_ADMIN etc. to? > how do we make sure that we (XFS) avoid breaking existing XFS tools? I > guess the default compatibility handler for all of those new hooks would > be "return capable(CAP_SYS_ADMIN) ? 0 : -EPERM;" and then other LSMs > could restrict that further if so configured. > > Seriously, I don't know that much about how LSMs actually perform > security checks -- it looks like a number of them can be active > simultaneously, and we just call each of them in a chain until one of > them denies permission or we run out of LSMs and allow it? > Correct. > FWIW I didn't have a particular security or threat model in mind when I > made the above list; all I did was break up the existing CAP_SYS_ADMIN > into rough functional areas. Maybe it makes sense, but maybe I'm > rambling. :) > > --D > > > You can build that model where for example only an administrative > > login from a trusted console may launch processes to do that > > management. > > > > Or you could - if things were not going around the LSM hooks. > > > > Alan > -- James Morris <jmorris@xxxxxxxxx>
