From: Thiebaud Weksteen <tweek@google.com>
To: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: Matthew Garrett <mjg59@google.com>,
linux-efi@vger.kernel.org,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Matt Fleming <matt@codeblueprint.co.uk>,
linux-kernel@vger.kernel.org, tpmdd-devel@lists.sourceforge.net,
peterhuewe@gmx.de,
Jason Gunthorpe <jgunthorpe@obsidianresearch.com>,
tpmdd@selhorst.net
Subject: Re: [PATCH v2 2/3] efi: call get_event_log before ExitBootServices
Date: Mon, 18 Sep 2017 14:28:45 +0200 [thread overview]
Message-ID: <CA+zpnLfs=DhW6kgbLV63_XzmKS7VnGGE0ecbFBZ0bu4wx3Jf+w@mail.gmail.com> (raw)
In-Reply-To: <20170914190247.rrbdzdexjjywxipf@linux.intel.com>
On Thu, Sep 14, 2017 at 9:02 PM, Jarkko Sakkinen
<jarkko.sakkinen@linux.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@linux.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@google.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
next prev parent reply other threads:[~2017-09-18 12:29 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-11 10:00 [PATCH v2 0/3] Call GetEventLog before ExitBootServices Thiebaud Weksteen
2017-09-11 10:00 ` [PATCH v2 1/3] tpm: move tpm_eventlog.h outside of drivers folder Thiebaud Weksteen
2017-09-11 10:00 ` [PATCH v2 2/3] efi: call get_event_log before ExitBootServices Thiebaud Weksteen
2017-09-13 14:49 ` kbuild test robot
2017-09-14 10:24 ` [tpmdd-devel] " Javier Martinez Canillas
2017-09-18 12:11 ` Thiebaud Weksteen
2017-09-18 12:49 ` Javier Martinez Canillas
2017-09-14 18:43 ` Jarkko Sakkinen
2017-09-14 18:48 ` Matthew Garrett
2017-09-14 19:02 ` Jarkko Sakkinen
2017-09-15 4:06 ` Jarkko Sakkinen
2017-09-18 12:28 ` Thiebaud Weksteen [this message]
2017-09-18 17:56 ` Jarkko Sakkinen
2017-09-11 10:00 ` [PATCH v2 3/3] tpm: parse TPM event logs based on EFI table Thiebaud Weksteen
2017-09-11 16:47 ` Jason Gunthorpe
2017-09-12 8:48 ` Thiebaud Weksteen
2017-09-18 12:38 ` Thiebaud Weksteen
2017-09-18 16:28 ` Jason Gunthorpe
2017-09-13 16:27 ` kbuild test robot
2017-09-13 16:43 ` Thiebaud Weksteen
2017-09-14 18:47 ` Jarkko Sakkinen
2017-09-18 12:33 ` Thiebaud Weksteen
2017-09-13 18:59 ` [PATCH v2 0/3] Call GetEventLog before ExitBootServices Jarkko Sakkinen
2017-09-14 10:21 ` [tpmdd-devel] " Javier Martinez Canillas
2017-11-03 15:27 ` Jarkko Sakkinen
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