[RFC PATCH v2 1/2] tpm, tpm_tis: Introduce TPM_IOC_SET_LOCALITY

[Ard Biesheuvel]

On Sat, 2 Nov 2024 at 11:38, Jarkko Sakkinen <jarkko at kernel.org> wrote:
>
> On Sat Nov 2, 2024 at 11:02 AM EET, Ard Biesheuvel wrote:
> > Same for the ioctl() [as well as the read-write sysfs node]: looking
> > at the code (patch 19/20) it doesn't seem like user space needs to be
> > able to modify this at all, at least not for the patch set as
> > presented. So for now, can we just stick with making the sysfs node
> > read-only?
>
> Short answer: I have no idea. I would not mind that but neither
> the commit message for TPM give a clue on this. Actually, I *do
> not care* if it is RO and RW but I'm neither good at guessing
> random shit.
>

You were cc'ed on the rest of the series, no?

Shall we clarify this first, before proposing patches that introduce
new ioctls() and kernel command line parameters to a security
sensitive subsystem?

My reading of 19/20 is that the secure launch module sets the default
locality, and given that it can be built as a module, setting the
default locality needs to be exported to modules (but as I indicated,
this should probably be in a TPM internal module namespace)

If setting the default locality from user space is a requirement down
the road, we can discuss it then. For now, let's not go off into the
weeds and derail this series even more.