Re: [PATCH 0/4][RFC v2] Introduce the in-kernel hibernation encryption

[joeyli]

On Thu, Aug 09, 2018 at 11:43:20AM +0800, Yu Chen wrote:
> Hi,
> On Wed, Aug 08, 2018 at 07:58:45PM +0200, Pavel Machek wrote:
> > On Mon 2018-08-06 18:39:58, joeyli wrote:
> > > On Mon, Aug 06, 2018 at 04:45:34PM +0800, Yu Chen wrote:
> > > > Hi Pavel,
> > > > On Sun, Aug 05, 2018 at 12:02:00PM +0200, Pavel Machek wrote:
> > > > > Hi!
> > > > > 
> > > > > > > User space doesn't need to involve. The EFI root key is generated by
> > > > > > > EFI boot stub and be transfer to kernel. It's stored in EFI boot service
> > > > > > > variable that it can only be accessed by trusted EFI binary when
> > > > > > > secure boot is enabled.
> > > > > > >
> > > > > > Okay, this apply to the 'suspend' phase, right?
> > > > > > I'm still a little confused about the 'resume' phase.
> > > > > > Taking encryption as example(not signature),
> > > > > > the purpose of doing hibernation encryption is to prevent other users
> > > > > > from stealing ram content. Say, user A uses a  passphrase to generate the
> > > > > 
> > > > > No, I don't think that's purpose here.
> > > > > 
> > > > > Purpose here is to prevent user from reading/modifying kernel memory
> > > > > content on machine he owns.
> > > > >
> > > > Say, A puts his laptop into hibernation and walks away,
> > > > and B walks by, and opens A's laptop and wakes up the system and he
> > > > can do what he wants. Although EFI key/TPM trusted key is enabled,
> > > > currently there's no certification during resume, which sounds
> > > > unsafe to me. Afterall, the original requirement is to probe
> > > > user for password during resume, which sounds more natural.
> > > 
> > > OK, I saw your case. This is a physical accessing.
> > > 
> > > I have a question: The suspend to memory also has the same behavior
> > > and more people are using suspend. Should we think a common solution
> > > to cover S3 and S4? 
> > 
> > Well, we have similar problem during runtime, too ;-).
> > 
> > Anyway, I don't think we should encrypt memory during S3 in kernel.
> > 
> It seems that Joey was talking about certification(something like login)
> rather than encryption?
>

Actually I do not have good idea.

Joey Lee