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

Dmitry Kasatkin
2014-06-10T21:40:53Z

On 11 June 2014 00:34, Dmitry Kasatkin <dmitry.kasatkin@gmail.com> wrote:
> 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

I must admit that bootloader replacement is not related to kernel...

It is just paranoia...

- dmitry