On 07/17/2018 01:22 PM, Philip Tricca wrote: > 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.
It was a misnomer to throw TIS in that statement since TSS is really the software part, bad habit on my part to refer to them collectively. I was just making a short collective statement that TSS as a whole provides a set of layers to provide higher abstractions and yes one of those layers is the one is the C code that implements the hardware interface. My apologies for the vague statement. > Philip > v/r, dps _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel
