------- Comment From daniel.axte...@ibm.com 2020-11-19 20:25 EDT------- Hi,
I think that's the only feature patch required. There's not a lot because at this stage it's all based on static keys. So unlike the OpenPower secure boot, there's no code to interact with keys stored in firmware. There is one config change that we also need: because there are no keys advertised by firmware or early boot, and because lockdown requires that kexec kernels be signed, we need to get the kernel signing key into the .ima keyring somehow. One way to do this is at boot with IMA_X509_PATH, but it can also be done at runtime. In either case, however, the CA that signs the kernel signing key needs to be built in to the kernel's .builtin_trusted_keys keyring. I haven't attempted this because I don't know much about how the signing process works in your build infrastructure, but I'm happy to help. Of course, I expect there will also be bug fixes later! Kind regards, Daniel -- 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: Incomplete Status in linux package in Ubuntu: Incomplete Bug description: == Comment: #2 - Daniel John Axtens <daniel.axte...@ibm.com> - 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 : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
