Re: [PATCH v2 2/3] efi: call get_event_log before ExitBootServices
Matthew Garrett <[email protected]>
| Newsgroups | net.sourceforge.lists.tpmdd-devel,org.kernel.vger.linux-efi,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <CACdnJuu2Aq1mvdvooBgC3-1jfi3CPnZ6WGysOGc2Xizm-mbU0w@mail.gmail.com> |
On Thu, Sep 14, 2017 at 11:43 AM, Jarkko Sakkinen <jarkko.sakkinen-VuQAYsv1563Yd54FQh9/[email protected]> wrote: > On Mon, Sep 11, 2017 at 12:00:21PM +0200, Thiebaud Weksteen wrote: >> With TPM 2.0 specification, the event logs may only be accessible by >> calling an EFI Boot Service. Modify the EFI stub to copy the log area to >> a new Linux-specific EFI configuration table so it remains accessible >> once booted. >> >> When calling this service, it is possible to specify the expected format >> of the logs: TPM 1.2 (SHA1) or TPM 2.0 ("Crypto Agile"). For now, only the >> first format is retrieved. >> >> Signed-off-by: Thiebaud Weksteen <[email protected]> > > With a quick skim the code change looks good but I remember from > Matthew's talk that there was this issue that ExitBootServices() would > cause a yet another event? > > I guess you could manually synthetize that event by reading the PCR > values right after ExitBootServices()? I think that would involve breaking SHA1… the information should be available in the TCG_TREE_FINAL_EVENTS configuration table, so it /should/ just be a matter of merging the events from that into the event log.