Re: [PATCH] security: Fix IMA Kconfig for dependencies on ARM64

[Mimi Zohar <zohar@linux.vnet.ibm.com>]

On Mon, 2018-03-12 at 17:05 -0600, Jason Gunthorpe wrote:
> On Mon, Mar 12, 2018 at 06:58:45PM -0400, Mimi Zohar wrote:
> > On Mon, 2018-03-12 at 15:59 -0600, Jason Gunthorpe wrote:
> > > On Mon, Mar 12, 2018 at 05:53:18PM -0400, Mimi Zohar wrote:
> > > 
> > > > Using Kconfig to force the TPM to be builtin is not required, but
> > > > helpful.  Users interested in IMA-measurement could configure the TPM
> > > > as builtin themselves.  Without the TPM builtin, IMA goes into TPM-
> > > > bypass mode.
> > > 
> > > This issues, broadly speaking, we have lots of TPM drivers, selecting
> > > only some to actually support IMA shows we have some kind of problem
> > > here.
> > 
> > True, IMA is not selecting the older TPM vendor specific modules, but
> > only the newer TPM_TIS and now TPM_CRB modules.  That doesn't imply
> > that IMA only supports some TPMs.  It means that by default, these
> > TPMs are builtin.  Anyone building a kernel, can select the vendor
> > specific TPM to be builtin.
> 
> That doesn't help distros, which is the main point of the complaint
> with this scheme :)

Years ago because of faulty TPM drivers, IMA was disabled in one of
the main distro's.  Deciding which vendor specific TPMs should be
builtin, is a discussion between the distro's and TPM vendors.

Mimi