Re: [PATCH 1/5 v2] PM / hibernate: Create snapshot keys handler

[Jarkko Sakkinen]

On Thu, Jan 10, 2019 at 02:11:55AM +0800, joeyli wrote:
> > Well, I think here, if we were actually trying to solve the problem of
> > proving the hibernated image were the same one we would need to prove
> > some log of the kernel operation came to a particular value *after* the
> > hibernated image were restored ... it's not really possible to
> > condition key release which must occur before the restore on that
> > outcome, so it strikes me we need more than a simple release bound to
> > PCR values.
> >
> 
> hm... I am studying your information. But I have a question...
> 
> If PCR is not capped and the root be compromised, is it possible that a
> sealed bundle also be compromised? 
> 
> Is it possible that kernel can produce a sealed key with PCR by TPM when
> booting? Then kernel caps a PCR by a constant value before the root is
> available for userland. Then the sealed key can be exposed to userland
> or be attached on hibernate image. Even the root be compromised, the TPM
> trusted key is still secure.

I think this even might be reasonable. Especially when we land James'
encrypted sessions patches at some point.

/Jarkko