From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thiebaud Weksteen Subject: Re: [PATCH v2 2/3] efi: call get_event_log before ExitBootServices Date: Mon, 18 Sep 2017 14:28:45 +0200 Message-ID: References: <20170911100022.7251-1-tweek@google.com> <20170911100022.7251-3-tweek@google.com> <20170914184126.eevnstwq3i6fiq4j@linux.intel.com> <20170914190247.rrbdzdexjjywxipf@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20170914190247.rrbdzdexjjywxipf-VuQAYsv1563Yd54FQh9/CA@public.gmane.org> Sender: linux-efi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Jarkko Sakkinen Cc: Matthew Garrett , linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Ard Biesheuvel , Matt Fleming , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, tpmdd-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, peterhuewe-Mmb7MZpHnFY@public.gmane.org, Jason Gunthorpe , tpmdd-yWjUBOtONefk1uMJSBkQmQ@public.gmane.org List-Id: tpmdd-devel@lists.sourceforge.net On Thu, Sep 14, 2017 at 9:02 PM, Jarkko Sakkinen wrote: > On Thu, Sep 14, 2017 at 11:48:54AM -0700, Matthew Garrett wrote: >> On Thu, Sep 14, 2017 at 11:43 AM, Jarkko Sakkinen >> 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 for= mat >> >> of the logs: TPM 1.2 (SHA1) or TPM 2.0 ("Crypto Agile"). For now, onl= y the >> >> first format is retrieved. >> >> >> >> Signed-off-by: Thiebaud Weksteen >> > >> > 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=E2=80=A6 the information should= be > > You are absolutely right, was not thinking clearly :-) > >> 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. > > Right, it is available through runtime services. Why this isn't part > of the patch set? This is not included yet as this table (EFI_TCG2_FINAL_EVENTS_TABLE_GUID) relies on the TPM2 format for the log entries (TCG_PCR_EVENT2, "Crypto Agile"). I first plan to add the parsing of this log version (ie, efi_retrieve_tpm2_eventlog_2) before adding the merging of both tables. But these will be separate patch sets. > > /Jrakko > > /Jarkko