lkml.org 
[lkml]   [2019]   [Apr]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v2] KEYS: Make use of platform keyring for module signature verify
From
Date
On Thu, 2019-04-25 at 07:55 -0400, Mimi Zohar wrote:
> On Wed, 2019-04-24 at 14:33 +0000, Robert Holmes wrote:
> > This patch completes commit 278311e417be ("kexec, KEYS: Make use of
> > platform keyring for signature verify") which, while adding the
> > platform keyring for bzImage verification, neglected to also add
> > this keyring for module verification.
> >
> > As such, kernel modules signed with keys from the MokList variable
> > were not successfully verified.
>
> Using the platform keyring keys for verifying kernel modules was not
> neglected, but rather intentional. This patch description should
> clearly explain the reason for needing to verify kernel module
> signatures based on the pre-boot keys. (Hint: verifying kernel
> modules based on the pre-boot keys was previously rejected.)

To clarify here: most Linux systems use shim/mok to pivot the root of
trust away from the Secure Boot db variable to the new MokList/shim
built in keys. This makes the actual secure boot db outside the
expected Linux Kernel trust boundary *unless* the user has taken
ownership of the system and is actually using db for their own trusted
keys. This makes the policy for what pre-boot keys to trust within the
Linux boundary very complex, which is why we default to not using the
pre-boot keys at all.

James

\
 
 \ /
  Last update: 2019-04-25 21:47    [W:0.056 / U:0.832 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site