Sorry for the delayed response here, it's taken me a while to get some of the needed information.
In general this should be fine. One thing to note is that the key is self-signed, so we will need to add the signing key itself into .builtin_trusted_keys. This should still allow loading the key into the IMA keyring. It might not be necessary to do so, if IMA trusts keys in .builtin_trusted_keys for signing kexec kernels (I don't know if it does or not), but it seems to be that structuring this as though the CA and signing keys are separate keys is a good idea to ensure that this continues to work if the key setup ever changes in the future. I'll work on getting some test packages put together in a PPA for testing. Let me know if you see any changes which need to be made as a result of the information I've provided. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1903288 Title: Power guest secure boot with static keys: kernel portion Status in The Ubuntu-power-systems project: Triaged Status in linux package in Ubuntu: New Bug description: == Comment: #2 - Daniel John Axtens <[email protected]> - 2020-11-05 20:15:10 == This is the kernel side of changes needed for LPAR/guest secure boot. Because Ubuntu keeps its kernels so wonderfully up to date, I don't think there are any extra patches you need to pick up. (I'll double- check against the 21.04 tree once my git pulls finish!) However, we potentially need some configuration changes to make sure kexec-ing into a crashdump kernel still works. Because Lockdown requires that kexec kernels are signed by a key trusted by IMA, the public key for used for signing the kdump kernel needs to be in the IMA keyring or the platform keyring. For host secure boot (and in the UEFI case), it's loaded into the platform keyring. But in the case of guest secure boot with static keys, it's not loaded into the platform keyring so it needs to be loaded into the IMA keyring. This is easy enough to do. Firstly, load the Secure Boot CA into the .primary_trusted_keys keyring via the CONFIG_SYSTEM_TRUSTED_KEYS property. We assume the key used to sign the kernel is signed by this CA. Then, enable IMA_LOAD_X509, which allows certificates signed by a key on the .primary_trusted_keys keyring to be loaded into the IMA keyring. Then set IMA_X509_PATH to provide a path to the signing key on installed file system. (It may also be possible to do this step in userspace, so long as the CA is trusted by the kernel.) Then that key will be loaded into the .ima keyring at boot and be used to appraise the kexec kernel for crashdumps. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-power-systems/+bug/1903288/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
