Re: [PATCH 0/4] KEYS: validate key trust with owner and builtin keys only

Dmitry Kasatkin
2014-06-10T21:34:33Z

On 11 June 2014 00:25, Matthew Garrett <mjg59@srcf.ucam.org> wrote:
> On Wed, Jun 11, 2014 at 12:17:53AM +0300, Dmitry Kasatkin wrote:
>
>> It is probably just a paranoia...
>> Kconfig MODULE_SIG_UEFI should tell about threat of loading kernel
>> modules from NSA or Lenovo signed by MS or Lenovo keys..
>>
>> This hole is opened without warning...
>
> It's not typically a hole. If an attacker has root they can just replace
> your bootloader with one signed by a trusted key and then have that
> modify the kernel before booting it.
>
> If you're using a TPM then you can mitigate this, but if you have a TPM
> then you're already performing some extra steps during the boot process.
> Just add a sysfs knob that lets you drop the db keys and incorporate
> that into the TPM management code.
>
> --
> Matthew Garrett | mjg59@srcf.ucam.org

I was expecting this boot loader answer.

Indeed, if system is design to prevent online modification of bootloader then
kernel parameters are protected as well...

My statement is still valid. It is a hole...

To prevent the hole it should be explained that one might follow
certain instructions
to take ownership of your PC. Generate your own keys and remove MS and
Vendor ones...

It is paranoia? May be not.

- Dmitry