On 08/07/15 at 09:09am, Vivek Goyal wrote:
On Fri, Aug 07, 2015 at 07:15:57AM -0400, Josh Boyer wrote:
> On Fri, Aug 7, 2015 at 3:41 AM, Dave Young <dyoung(a)redhat.com> wrote:
> > Kexec reboot in case secure boot enabled does not keep the secure boot mode
> > in new kernel, so later one can load unsigned kernel via legacy kexec_load.
>
> Hm. Wasn't there code being written so that one could disable legacy
> kexec and only have kexec_file? Perhaps that is queued for 4.3. I'm
> wondering if as a general security measure we want to only have
> kexec_file available in Fedora when that is possible.
The way config options are in fedora, kexec_file() enforces signature
verification. So if you disable legacy kexec, then it will not be possible
to kexec unsigned kernels.
I think we should be able to modify kexec_file() such that it enfornces
signature only when secureboot is enabled otherwise acts like a legacy
call. Then we should be able to get rid of legacy kexec call.
But there are still use case that one need enforce verifying signature even without secure
boot..
But there is a long way to go before we get there. legacy call is well
tested and new call is barely used anywhere. First we need to have
confidence that new call can handle most of the use cases.
Thanks
Vivek
Thanks
Dave