> On Sep 15, 2021, at 11:57 AM, Jarkko Sakkinen <jarkko@xxxxxxxxxx> wrote: > > 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 [1]. 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 [2], [3], [4]. 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 [5]. 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 [5] and shim [6] 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)? It is not hard, that is the setup I use for my testing. Upstream shim is located here [1]. Or you can use my repo which contains the necessary changes [2]. [1] https://github.com/rhboot/shim [2] https://github.com/esnowberg/shim/tree/mokvars-v2
