[PATCH v2 0/4] rpmb subsystem, uapi and virtio-rpmb driver

[PATCH v2 0/4] rpmb subsystem, uapi and virtio-rpmb driver

[Shyam Saini]

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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

RE: [PATCH v2 0/4] rpmb subsystem, uapi and virtio-rpmb driver

[Zhu, Bing]

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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)

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(a)linaro.org
Cc: code(a)tyhicks.com; Matti.Moell(a)opensynergy.com; arnd(a)linaro.org; Zhu, Bing <bing.zhu@intel.com>; hmo(a)opensynergy.com; ilias.apalodimas(a)linaro.org; joakim.bech(a)linaro.org; linux-kernel(a)vger.kernel.org; linux-mmc(a)vger.kernel.org; linux-scsi(a)vger.kernel.org; maxim.uvarov(a)linaro.org; ruchika.gupta(a)linaro.org; Winkler, Tomas <tomas.winkler@intel.com>; ulf.hansson(a)linaro.org; Huang, Yang <yang.huang@intel.com>; sumit.garg(a)linaro.org; jens.wiklander(a)linaro.org; op-tee(a)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

Re: [PATCH v2 0/4] rpmb subsystem, uapi and virtio-rpmb driver

[Ilias Apalodimas]

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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

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(a)linaro.org
> Cc: code(a)tyhicks.com; Matti.Moell(a)opensynergy.com; arnd(a)linaro.org; Zhu, Bing <bing.zhu@intel.com>; hmo(a)opensynergy.com; ilias.apalodimas(a)linaro.org; joakim.bech(a)linaro.org; linux-kernel(a)vger.kernel.org; linux-mmc(a)vger.kernel.org; linux-scsi(a)vger.kernel.org; maxim.uvarov(a)linaro.org; ruchika.gupta(a)linaro.org; Winkler, Tomas <tomas.winkler@intel.com>; ulf.hansson(a)linaro.org; Huang, Yang <yang.huang@intel.com>; sumit.garg(a)linaro.org; jens.wiklander(a)linaro.org; op-tee(a)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

Re: [PATCH v2 0/4] rpmb subsystem, uapi and virtio-rpmb driver

[Sumit Garg]

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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.

-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(a)linaro.org
> > Cc: code(a)tyhicks.com; Matti.Moell(a)opensynergy.com; arnd(a)linaro.org; Zhu, Bing <bing.zhu@intel.com>; hmo(a)opensynergy.com; ilias.apalodimas(a)linaro.org; joakim.bech(a)linaro.org; linux-kernel(a)vger.kernel.org; linux-mmc(a)vger.kernel.org; linux-scsi(a)vger.kernel.org; maxim.uvarov(a)linaro.org; ruchika.gupta(a)linaro.org; Winkler, Tomas <tomas.winkler@intel.com>; ulf.hansson(a)linaro.org; Huang, Yang <yang.huang@intel.com>; sumit.garg(a)linaro.org; jens.wiklander(a)linaro.org; op-tee(a)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

Re: [PATCH v2 0/4] rpmb subsystem, uapi and virtio-rpmb driver

[Ilias Apalodimas]

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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(a)linaro.org
> > > Cc: code(a)tyhicks.com; Matti.Moell(a)opensynergy.com; arnd(a)linaro.org; Zhu, Bing <bing.zhu@intel.com>; hmo(a)opensynergy.com; ilias.apalodimas(a)linaro.org; joakim.bech(a)linaro.org; linux-kernel(a)vger.kernel.org; linux-mmc(a)vger.kernel.org; linux-scsi(a)vger.kernel.org; maxim.uvarov(a)linaro.org; ruchika.gupta(a)linaro.org; Winkler, Tomas <tomas.winkler@intel.com>; ulf.hansson(a)linaro.org; Huang, Yang <yang.huang@intel.com>; sumit.garg(a)linaro.org; jens.wiklander(a)linaro.org; op-tee(a)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

Re: [PATCH v2 0/4] rpmb subsystem, uapi and virtio-rpmb driver

[Jens Wiklander]

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Hi Alex,

On Fri, Jun 2, 2023 at 10:26 AM Ilias Apalodimas
<ilias.apalodimas@linaro.org> wrote:
>
> 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

I was trying to create a setup to test this. I've added the kernel
patches on top of https://github.com/linaro-swg/linux/tree/optee. The
QEMU branch is a bit dated and I had to add
3a845a214b42 target/arm: allow setting SCR_EL3.EnTP2 when FEAT_SME is
implemented
d4a7b0ef1a03 hw/arm/boot: set CPTR_EL3.ESM and SCR_EL3.EnTP2 when
booting Linux with EL3
9745a003f878 hw/intc/arm_gicv3: fix prio masking on pmr write
beeec926d24a target/arm: mark SP_EL1 with ARM_CP_EL3_NO_EL2_KEEP
on top of that branch to be able to boot to the Linux kernel.

I have the vhost-user-rpmb process running and connected with QEMU,
but around (guessing really) when the RPMB subsystem is initializing
the process dies with:
================ Vhost user message ================
Request: VHOST_USER_SET_VRING_ADDR (9)
Flags:   0x1
Size:    40
vhost-user-rpmb-INFO: 18:58:08.312: vrpmb_process_msg: msg
VHOST_USER_SET_VRING_ADDR(9)
vhost_vring_addr:
    index:  0
    flags:  0
    desc_user_addr:   0x00007ff15fa91000
    used_user_addr:   0x00007ff15fa91080
    avail_user_addr:  0x00007ff15fa91040
    log_guest_addr:   0x0000000041c91080
Setting virtq addresses:
    vring_desc  at (nil)
    vring_used  at (nil)
    vring_avail at (nil)

(vhost-user-rpmb:3236474): vhost-user-rpmb-CRITICAL **: 18:58:08.312:
Invalid vring_addr message

Among other options, I'm starting QEMU with -machine
virt,secure=on,mte=off,gic-version=3,virtualization=false to enable
the secure world.

Do you have an idea of what might be wrong? Where should I start looking?

Thanks,
Jens

>
> /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(a)linaro.org
> > > > Cc: code(a)tyhicks.com; Matti.Moell(a)opensynergy.com; arnd(a)linaro.org; Zhu, Bing <bing.zhu@intel.com>; hmo(a)opensynergy.com; ilias.apalodimas(a)linaro.org; joakim.bech(a)linaro.org; linux-kernel(a)vger.kernel.org; linux-mmc(a)vger.kernel.org; linux-scsi(a)vger.kernel.org; maxim.uvarov(a)linaro.org; ruchika.gupta(a)linaro.org; Winkler, Tomas <tomas.winkler@intel.com>; ulf.hansson(a)linaro.org; Huang, Yang <yang.huang@intel.com>; sumit.garg(a)linaro.org; jens.wiklander(a)linaro.org; op-tee(a)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

Re: [PATCH v2 0/4] rpmb subsystem, uapi and virtio-rpmb driver

[Shyam Saini]

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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(a)linaro.org
>>>> Cc: code(a)tyhicks.com; Matti.Moell(a)opensynergy.com; arnd(a)linaro.org; Zhu, Bing <bing.zhu@intel.com>; hmo(a)opensynergy.com; ilias.apalodimas(a)linaro.org; joakim.bech(a)linaro.org; linux-kernel(a)vger.kernel.org; linux-mmc(a)vger.kernel.org; linux-scsi(a)vger.kernel.org; maxim.uvarov(a)linaro.org; ruchika.gupta(a)linaro.org; Winkler, Tomas <tomas.winkler@intel.com>; ulf.hansson(a)linaro.org; Huang, Yang <yang.huang@intel.com>; sumit.garg(a)linaro.org; jens.wiklander(a)linaro.org; op-tee(a)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
>

RE: [PATCH v2 0/4] rpmb subsystem, uapi and virtio-rpmb driver

[Shyam Saini]

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Hi Bing,

Other than PCRs we also want to store Non volatile ftpm data (NVData), 
storing these in volatile DDR shared memory will be a spec violation.

Best Regards,
Shyam

> 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)
>
> 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(a)linaro.org
> Cc: code(a)tyhicks.com; Matti.Moell(a)opensynergy.com; arnd(a)linaro.org; Zhu, Bing <bing.zhu@intel.com>; hmo(a)opensynergy.com; ilias.apalodimas(a)linaro.org; joakim.bech(a)linaro.org; linux-kernel(a)vger.kernel.org; linux-mmc(a)vger.kernel.org; linux-scsi(a)vger.kernel.org; maxim.uvarov(a)linaro.org; ruchika.gupta(a)linaro.org; Winkler, Tomas <tomas.winkler@intel.com>; ulf.hansson(a)linaro.org; Huang, Yang <yang.huang@intel.com>; sumit.garg(a)linaro.org; jens.wiklander(a)linaro.org; op-tee(a)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
>