On Mon, Jul 16, 2018 at 12:33:42PM -0400, Daniel P. Smith wrote: > On 07/16/2018 08:06 AM, Daniel Kiper wrote: > > On Mon, Jul 02, 2018 at 06:35:08PM +0200, Daniel Kiper wrote: > >> Hi Daniel, > >> > >> On Sun, Jul 01, 2018 at 07:09:30PM -0400, Daniel P. Smith wrote: > >>> Greetings, > >>> > >>> I have a measured boot implementation I have been working on that > >>> introduces a DRTM relocator that I would like to eventually upstream. > >>> This work does rely on the ability to access a TPM 1.2 chip from within > >>> Grub2. I am aware of Matthew Garrett's pending patch to add core TPM > >>> support[1] but that is limited to UEFI environments. My target > >>> environment uses Coreboot with the TCG BIOS payload to launch the > >>> environment. For TPM support I am using code picked out of the > >>> TrustedGRUB2 fork[2]. As a precursor to upstreaming my DRTM relocator, I > >>> would like to see if I could find a way to generically introduce TPM > >>> support into Grub2 that support's Matthew's UEFI backend, TrustedGrub2's > >>> TPM 1.2 raw I/O, as well as leave a path for TPM2 raw I/O. In both > >>> implementations TPM support is include as an x86 device when in fact > >>> they can also be found in ARM devices, which is on my wish list of > >>> future devices I would like to support. With all of this in mind, I > >>> wanted to open a discussion on the best way to implement generic TPM > >>> support. In Matthew's approach TPM is implemented under > >>> grub-core/commands while TrustedGRUB2 is split between grub-core/kern > >>> and grub-core/tpm. IMHO TPM functionality should be divided into HW > >>> interfaces, TPM command processing, and higher order TPM operations. If > >>> the logic was segmented in this manner, what are other's opinions on > >>> where segments of logic should reside within the Grub2 source tree? > >>> > >>> > >>> [1] http://lists.gnu.org/archive/html/grub-devel/2017-07/msg00005.html > >>> [2] https://github.com/Rohde-Schwarz-Cybersecurity/TrustedGRUB2 > > > > In general I am not against reorganization you are mentioning above. > > Though I think that then you should rearange Matthew code and repost > > it. Of course if Matthew does not object. > > I can align Matthew's code or if he would like, he is more than welcome > to collaborate on the solution. > > > Another thing is the verifiers framework. It would be nice if you could > > hook your work there. Though you have to remember about other users like > > UEFI secure boot > > (https://lists.xen.org/archives/html/xen-devel/2017-07/msg00985.html; > > I am going to revive work on this patch) or GPG signatures. So, please > > take a look at that code at git://git.savannah.gnu.org/grub.git, > > phcoder/verifiers branch. If it works for you I will post the patches, > > with minor fixes and improvements which are worth doing, for review (of > > course if Vladimir does not object). If you discover any issues with the > > verifiers framework just drop me a line and then we will try to fix them. > > Yes, I figured I would be using the verifier framework. The only > suggestion I would have based on my work is that I am going to have to > establish a TPM event log since I will be doing raw IO with the TPM. I > think it would be useful if the verifier framework had an event log > component that verifier modules could log events that they want to have > passed to the OS kernel being booted. For an example of how to pass the > log along to the OS kernel, for TrenchBoot the plan is to pass via the > setup data boot protocol field of Linux. For mutliboot kernels, the log > could easily be passed as a mb module. Let me know what you think. > > > And another thing... Could not we reuse Philip TPM 2.0 work in GRUB2 > > somehow? > > Phil's work is dealing with the TSS/TIS software layers which provide > higher abstractions over the TPM.
This is false. The APIs from the TSS are ignorant of and unrelated to the TIS. Further, the "System API" has a 1:1 correspondence with TPM2 commands effectively providing no abstraction beyond the serialization of C types to / from the TPM2 command / response byte stream. This is why we recommend that only firmware and "expert" applications use it directly. Philip _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel
