[PATCH v6 00/13] Enroll kernel keys thru MOK
jarkko at kernel.org
Wed Sep 15 17:57:39 UTC 2021
On Tue, 2021-09-14 at 17:14 -0400, Eric Snowberg wrote:
> Back in 2013 Linus requested a feature to allow end-users to have the
> ability "to add their own keys and sign modules they trust". This was
> his *second* order outlined here . There have been many attempts
> over the years to solve this problem, all have been rejected. Many
> of the failed attempts loaded all preboot firmware keys into the kernel,
> including the Secure Boot keys. Many distributions carry one of these
> rejected attempts , , . This series tries to solve this problem
> with a solution that takes into account all the problems brought up in
> the previous attempts.
> On UEFI based systems, this series introduces a new Linux kernel keyring
> containing the Machine Owner Keys (MOK) called machine. It also defines
> a new MOK variable in shim. This variable allows the end-user to decide
> if they want to load MOK keys into the machine keyring. Mimi has suggested
> that only CA keys contained within the MOK be loaded into the machine
> keyring. All other certs will load into the platform keyring instead.
> By default, nothing changes; MOK keys are not loaded into the machine
> keyring. They are only loaded after the end-user makes the decision
> themselves. The end-user would set this through mokutil using a new
> --trust-mok option . This would work similar to how the kernel uses
> MOK variables to enable/disable signature validation as well as use/ignore
> the db. Any kernel operation that uses either the builtin or secondary
> trusted keys as a trust source shall also reference the new machine
> keyring as a trust source.
> Secure Boot keys will never be loaded into the machine keyring. They
> will always be loaded into the platform keyring. If an end-user wanted
> to load one, they would need to enroll it into the MOK.
> Steps required by the end user:
> Sign kernel module with user created key:
> $ /usr/src/kernels/$(uname -r)/scripts/sign-file sha512 \
> machine_signing_key.priv machine_signing_key.x509 my_module.ko
> Import the key into the MOK
> $ mokutil --import machine_signing_key.x509
> Setup the kernel to load MOK keys into the .machine keyring
> $ mokutil --trust-mok
> Then reboot, the MokManager will load and ask if you want to trust the
> MOK key and enroll the MOK into the MOKList. Afterwards the signed kernel
> module will load.
> I have included links to both the mokutil  and shim  changes I
> have made to support this new functionality.
How hard it is to self-compile shim and boot it with QEMU (I
do not know even the GIT location of Shim)?
I'm all my SGX testing already with TianoCore and QEMU so I
thought it might not be that huge stretch to get testing env
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