[Skiboot] [PATCH] core/fast-reboot: disable fast-reboot when firmware secureboot is enabled
erichte at linux.ibm.com
Fri Apr 17 06:05:24 AEST 2020
On 4/14/20 10:54 PM, Oliver O'Halloran wrote:
> On Thu, Apr 9, 2020 at 8:14 AM Eric Richter <erichte at linux.ibm.com> wrote:
>> The possible impact of the current fast-reboot design on secure/trusted
>> boot is unclear and will likely need additional review and testing.
> Are you really expecting me to hard disable fast reboot on the basis
> of "I don't understand what this does"?
> We looked at it years ago and decided that the interaction with
> firmware secureboot was fine since a fast-reboot is roughlt the same
> as a kexec between host kernels. If you think that's wrong (it might
> be) then provide an actual explanation as to why.
We had concerns over OS secure boot, but after further discussions, decided
that this is something we will document and potentially address in a later
There is a potential issue regarding trusted boot -- only the firmware
measurement log will be persisted. Any higher-level, non-resettable PCRs will
not be able to be recalculated, which is a definite problem with IMA/kexec
measurements in skiroot for example. Since this isn't a strong blocking issue
however, we will include a strong recommendation against using this feature
in our documentation.
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