Messages in this thread | | | Date | Mon, 12 Jun 2023 17:49:17 -0700 (PDT) | From | Shyam Saini <> | Subject | Re: [PATCH v2 0/4] rpmb subsystem, uapi and virtio-rpmb driver |
| |
Thank you everyone for your valueable feedback.
Alex, are you planning submit this patch series ? Please let me know.
> On Thu, 1 Jun 2023 at 08:49, Sumit Garg <sumit.garg@linaro.org> wrote: >> >> On Thu, 1 Jun 2023 at 11:02, Ilias Apalodimas >> <ilias.apalodimas@linaro.org> wrote: >>> >>> Hi Bing >>> >>> On Thu, 1 Jun 2023 at 04:03, Zhu, Bing <bing.zhu@intel.com> wrote: >>>> >>>> As an alternative, Is it possible to change ftpm design not to depend on RPMB access at the earlier/boot stage? Because to my understanding, typically PCRs don't require persistent/NV storage (for example, before RPMB or tee-supplicant is ready, use TEE memory instead as temporary storage) >>> >>> I am not entirely sure this will solve our problem here. You are >>> right that we shouldn't depend on the supplicant to extend PCRs. But >>> what happens if an object is sealed against certain PCR values? We >>> are back to the same problem >> >> +1 >> >> Temporary storage may be a stop gap solution for some use-cases but >> having a fast path access to RPMB via kernel should be our final goal. >> I would suggest we start small with the MMC subsystem to expose RPMB >> access APIs for OP-TEE driver rather than a complete RPMB subsystem. > > I discussed with the OP-TEE maintainers about adding parts of the > supplicant in the kernel. The supplicant 'just' sends an ioctl to > store/read stuff anyway. So it would make sense to have a closer and > see if that looks reasonable. > Thanks > > /Ilias > >> >> -Sumit >> >>> >>> Thanks >>> /Ilias >>>> >>>> Bing >>>> >>>> IPAS Security Brown Belt (https://www.credly.com/badges/69ea809f-3a96-4bc7-bb2f-442c1b17af26) >>>> System Software Engineering >>>> Software and Advanced Technology Group >>>> Zizhu Science Park, Shanghai, China >>>> >>>> -----Original Message----- >>>> From: Shyam Saini <shyamsaini@linux.microsoft.com> >>>> Sent: Thursday, June 1, 2023 3:10 AM >>>> To: alex.bennee@linaro.org >>>> Cc: code@tyhicks.com; Matti.Moell@opensynergy.com; arnd@linaro.org; Zhu, Bing <bing.zhu@intel.com>; hmo@opensynergy.com; ilias.apalodimas@linaro.org; joakim.bech@linaro.org; linux-kernel@vger.kernel.org; linux-mmc@vger.kernel.org; linux-scsi@vger.kernel.org; maxim.uvarov@linaro.org; ruchika.gupta@linaro.org; Winkler, Tomas <tomas.winkler@intel.com>; ulf.hansson@linaro.org; Huang, Yang <yang.huang@intel.com>; sumit.garg@linaro.org; jens.wiklander@linaro.org; op-tee@lists.trustedfirmware.org >>>> Subject: [PATCH v2 0/4] rpmb subsystem, uapi and virtio-rpmb driver >>>> >>>> Hi Alex, >>>> >>>> [ Resending, Sorry for the noise ] >>>> >>>> Are you still working on it or planning to resubmit it ? >>>> >>>> [1] The current optee tee kernel driver implementation doesn't work when IMA is used with optee implemented ftpm. >>>> >>>> The ftpm has dependency on tee-supplicant which comes once the user space is up and running and IMA attestation happens at boot time and it requires to extend ftpm PCRs. >>>> >>>> But IMA can't use PCRs if ftpm use secure emmc RPMB partition. As optee can only access RPMB via tee-supplicant(user space). So, there should be a fast path to allow optee os to access the RPMB parititon without waiting for user-space tee supplicant. >>>> >>>> To achieve this fast path linux optee driver and mmc driver needs some work and finally it will need RPMB driver which you posted. >>>> >>>> Please let me know what's your plan on this. >>>> >>>> [1] https://optee.readthedocs.io/en/latest/architecture/secure_storage.html >>>> >>>> Best Regards, >>>> Shyam >
| |