On Wed, Oct 25, 2017 at 01:22:21PM -0700, Jerry Snitselaar wrote:

On Wed Oct 25 17, Jarkko Sakkinen wrote:

quoted

On Wed, Oct 25, 2017 at 07:17:17AM -0700, Matthew Garrett wrote:

quoted

On Wed, Oct 25, 2017 at 6:44 AM, Jarkko Sakkinen
[off-list ref] wrote:

quoted

I'm implementing a fix for CVE-2017-15361 that simply blacklists
vulnerable FW versions. I think this is the only responsible action from
my side that I can do.

I'm not sure this is ideal - do Infineon have any Linux tooling for
performing firmware updates, and if so will that continue working if
the device is blacklisted? It's also a poor user experience to have
systems using TPM-backed disk encryption keys suddenly rendered
unbootable, and making it as easy as possible for people to do an
upgrade and then re-seal secrets with new keys feels like the correct
approach.

I talked today with Alexander Steffen in the KS unconference and we
concluded that this would be a terrible idea.

Alexander stated the following things about FW updates (Alexander,
please correct me if I state something incorrectly or if you have
something to add):

* FW update can be constructed either in a way that the keys in the
 NVRAM are not cleared or in a way that they are cleared.
* FW update cannot be directly applied to the TPM but must come as
 part of the firmware update from the vendor.

If that is the case, can the two of you get Intel to update the fw
for the tpm in the nuc5i5myhe (slb9665) :) ? It has needed an update for a while, due
to issues with context management. My understanding (quite likely I misunderstood)
from a recent discussion with Peter was that it was possible to update the fw.

I don't know but I can at least forward the complains to the mother ship
:-)

It is fairly intuitive why dTPM cannot be updated without full firmware
update. It's part of the proprietary HW platform, not something
connected through PCI, USB or any standard bus.

/Jarkko
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