Re: [RFC 2/2] initramfs with digital signature protection

From: Josh Boyer
Date: Mon Apr 08 2013 - 16:18:04 EST


On Mon, Apr 8, 2013 at 4:09 PM, Vivek Goyal <vgoyal@xxxxxxxxxx> wrote:
> On Mon, Apr 08, 2013 at 03:43:49PM -0400, Mimi Zohar wrote:
>> On Fri, 2013-04-05 at 09:50 -0400, Vivek Goyal wrote:
>> > On Tue, Feb 05, 2013 at 11:55:09PM +0200, Kasatkin, Dmitry wrote:
>> >
>> > [..]
>> > > > Also I am assuming that from signed initramfs, keys will be loaded in
>> > > > appropriate keyrings and then keyring will be locked so that any
>> > > > tools from unsigned initramfs can not load additional keys.
>> > > >
>> > >
>> > > Exactly like that.
>> >
>> > Dmitry,
>> >
>> > [ Following up on this thread after a very long time ]
>> >
>> > I was thinking about this point that keys can be loaded from signed
>> > initramfs. But how is it better than embedding the keys in kernel the
>> > way we do for module signing and lock down ima keyring before control
>> > is passed to initramfs.
>> >
>> > Reason being, that anyway a user can not put its own keys in signed
>> > initramfs. Signed initramfs will be shipped by distribution. So then
>> > it does not matter whether distribution's keys are embedded in the
>> > kernel or are loaded from signed initramfs.
>>
>> Although both the early initramfs and the kernel are signed, building
>> the keys into the kernel implies a static set of predefined public keys,
>> while the initramfs could load, in addition to the distro keys, keys
>> from the UEFI databases.
>
> Kernel already loads all the keys from UEFI database and MOK into module
> keyring.

Small point of order: there are patches to allow the kernel to do this.
None of those patches are upstream.

josh
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