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

Pavel Machek
2018-08-08T17:50:42Z

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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

Define unsafe.

If you want security against bad people resuming your machines, please
take a look at existing uswsusp solutions. It defends against that.

If you want security against bad people tampering with your machines
physically, sorry, there's no way to defend against that.

But I thought you were trying to do something for secure boot, and "bad
person resumes your machine" is out of scope there.

So please always explain security against _what kind of attack_ you
are trying to improve; intelligent communication is not possible
without that.

Pavel

--
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