lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Mon, 18 Sep 2017 14:28:45 +0200 From: Thiebaud Weksteen <tweek@...gle.com> To: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com> Cc: Matthew Garrett <mjg59@...gle.com>, linux-efi@...r.kernel.org, Ard Biesheuvel <ard.biesheuvel@...aro.org>, Matt Fleming <matt@...eblueprint.co.uk>, linux-kernel@...r.kernel.org, tpmdd-devel@...ts.sourceforge.net, peterhuewe@....de, Jason Gunthorpe <jgunthorpe@...idianresearch.com>, tpmdd@...horst.net Subject: Re: [PATCH v2 2/3] efi: call get_event_log before ExitBootServices On Thu, Sep 14, 2017 at 9:02 PM, Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com> 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 >> <jarkko.sakkinen@...ux.intel.com> 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 <tweek@...gle.com> >> > >> > 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 > > 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
Powered by blists - more mailing lists