On Mon Nov 4, 2024 at 1:27 PM EET, Ard Biesheuvel wrote: > On Mon, 4 Nov 2024 at 12:18, Jarkko Sakkinen <jarkko@xxxxxxxxxx> wrote: > > > > On Mon Nov 4, 2024 at 12:57 PM EET, Daniel P. Smith wrote: > > > On 11/2/24 14:00, Jarkko Sakkinen wrote: > > > > On Sat Nov 2, 2024 at 5:22 PM EET, Jarkko Sakkinen wrote: > > > >> It is not really my problem but I'm also wondering how the > > > >> initialization order is managed. What if e.g. IMA happens to > > > >> initialize before slmodule? > > > > > > > > The first obvious observation from Trenchboot implementation is that it > > > > is 9/10 times worst idea ever to have splitted root of trust. Here it > > > > is realized by an LKM for slmodule. > > > > > > First, there is no conflict between IMA and slmodule. With your change > > > to make locality switching a one shot, the only issue would be if IMA > > > were to run first and issue a locality switch to Locality 0, thus > > > blocking slmodule from switching to Locality 2. As for PCR usage, IMA > > > uses the SRTM PCRs, which are completely accessible under Locality 2. > > > > Just pointing out a possible problem (e.g. with TPM2_PolicyLocality). > > > > > Honestly, a better path forward would be to revisit the issue that is > > > driving most of that logic existing, which is the lack of a TPM > > > interface code in the setup kernel. As a reminder, this issue is due to > > > the TPM maintainers position that the only TPM code in the kernel can be > > > the mainline driver. Which, unless something has changed, is impossible > > > to compile into the setup kernel due to its use of mainline kernel > > > constructs not present in the setup kernel. > > > > I don't categorically reject adding some code to early setup. We have > > some shared code EFI stub but you have to explain your changes > > proeprly. Getting rejection in some early version to some approach, > > and being still pissed about that years forward is not really way > > to go IMHO. > > > > Daniel has been nothing but courteous and patient, and you've waited > 11 revision to come up with some bikeshedding patches that don't > materially improve anything. > > So commenting on Daniel's approach here is uncalled for. > > Can we please converge on this? > > Daniel - if no component can be built as a module, there should be no > reason for the set_default_locality() hook to be exported to modules > right? And do we even need a sysfs node to expose this information? I provided patches with my sob's and spent time on making the delta absolute minimal to what exists already. If those are picked, I'm good. They are essentially drop-in replicas to the existing patches. BR, Jarkko
