Re: TPM: hibernate with IMA PCR 10

[Matthew Garrett]

On Mon, Aug 29, 2022 at 2:45 PM Ken Goldman <kgold@xxxxxxxxxxxxx> wrote:
>
> On 5/4/2022 7:20 PM, Evan Green wrote:
> > Enabling the kernel to be able to do encryption and integrity checks on
> > the hibernate image prevents a malicious userspace from escalating to
> > kernel execution via hibernation resume.  [snip]
>
> I have a related question.
>
> When a TPM powers up from hibernation, PCR 10 is reset.  When a
> hibernate image is restored:
>
> 1. Is there a design for how PCR 10 is restored?

I don't see anything that does that at present.

> 2. How are /sys/kernel/security/ima/[pseudofiles] saved and
> restored?

They're part of the running kernel state, so should re-appear without
any special casing. However, in the absence of anything repopulating
PCR 10, they'll no longer match the in-TPM value.