Re: [tboot-devel] tboot + TPM 2.0 + TXT (boot with grub2)

[Marco V. <mva...@go...>]

Hi Xiao, Greg,

Adding to what Greg said, I would start by loading a POLTYPE_ANY and then
checking the Event log from txt-stat to see if the policy has been read.
After that, go ahead and use the gen2 tools to create the policies.

Keep in mind that the logs you sent are not about the LCP but about the
Verified LCP (tboot specific ones, checked the Policy Engine verifies
everything). You will get more LCP information from the TPM Event Log.
Also, check the error codes after each failed boot.

Basically the steps I did to make sure everything was working were:

- Launch without any LCP.
- Launch with a VLCP, modifying the default one (manually)
- Launch with a LCP POLTYPE_ANY. (created manually or by gen2 tools)
- Launch with an LCP that checks the MLE (created by gen2 tools)

At each experiment check the TPM Event Log (from txt-stat). I could not
find a hardware that was working correctly out of the shelf, not even Intel
NUC's.

Best Regards,
Marco

On Thu, Jul 13, 2017 at 6:01 AM, Dr. Greg Wettstein <gr...@en...>
wrote:

> On Wed, Jul 12, 2017 at 06:01:02PM -0700, Xiao Li wrote:
>
> > Hi,
> >
> > Wish everyone has a good day.
>
> Hi Xiao, I hope this note finds you day and week going well.
>
> > I have been trying to use tpm2-tools and tboot to setup LCP policy
> > for my platform using TPM 2.0. I have successfully done it with
> > tboot provided nvdef and nvwrite with a TPM 1.2 chip on the same
> > host. However when it comes to TPM2.0 my setup never succeeds.
>
> Launch Control Policies on TXT/TPM2 are a bit of a problem.  We have
> poured a ton of time into resolving functionality issues with only
> limited success.
>
> First of all it would be helpful to know what hardware platform you
> are using as different platforms have different issues associated with
> them.  Depending on what the platform OEM has decided to do it may not
> even be possible to use TXT/TBOOT even if the processor and chipset
> technically support it.
>
> I'm assuming since you are using 0x204000A for the NVram attributes
> that this is a post-Broadwell platform?
>
> In addition what version of tboot are you using?  I see that they have
> the 1.9.6 up on Sourceforge.  If you are experimenting with TPM2 based
> systems you will want to be running that since earlier versions had no
> hope of working on TPM2 based hardware.
>
> > I have tried to use nvindex:
> > #0x01C10131
> > #0x01C10106
> > #0x01400001
> > they all behaved a bit different from each other, but all seem like tboot
> > failed to load launch control policy:
>
> The NVram index locations which should be used are defined by the ACM
> module you are using, which is in turn defined by your hardware
> platform.
>
> After you get the most recent release of the tboot package run the
> 'acminfo' command on your ACM module and look for the following in the
> output:
>
>          TPM info list:
>                  TPM capability:
>                       ext_policy: 0x3
>                       tpm_family : 0x3
>                       tpm_nv_index_set : 0x0
>
> The 'tpm_nv_index_set' value specifies the NVram index locations which
> will be used.  If it is 0x0 you will need to use the 'old' values, ie
> the 0x1400001 for the PO policy.
>
> We have not personally seen any hardware in the wild which is using
> the 'new' values.
>
> > My first attempt was using the following commands:
> >
> > tpm2_takeownership -o new -e new -l new
> > tpm2_nvdefine -x 0x01C10106 -a 0x40000001 -s 70 -t 0x204000A -P new
> > lcp2_mlehash --verbose --create --alg sha256 --cmdline
> > "logging=serial,memory,vga extpol=sha256" /boot/tboot.gz > mle_hash
> > lcp2_crtpolelt --verbose --create --type mle --alg sha256 --ctrl 0x00
> > --minver 0 --out tbootmle.elt mle_hash
> > lcp2_crtpollist --verbose --create --out list_unsig.lst tbootmle.elt
> > lcp2_crtpol --verbose --create --type list --pol list.pol --alg sha256
> > --data list.data list_unsig.lst
> > tpm2_nvwrite -x 0x01C10106 -a 0x40000001 -f list.pol -P new
>
> The lcp2_* tools will not create valid policies for TPM2 systems.  At
> a minimum they are not encoding valid hash function selector
> attributes into the policy files.
>
> I believe that the python based tools in the lcp-gen2 directory are
> the only hope for getting valid policy files.  Those are cumbersom so
> we are fiddling in our spare time trying to get the C based utilities
> to work properly.
>
> > Thanks in advance,
> > Xiao Li
>
> Hopefully the above information will get you started.
>
> If you report back to the list answer the questions above on what
> hardware you are using since that will be important in making further
> progress.
>
> Good luck wih your efforts and have a good remainder of the week.
>
> Greg
>
> As always,
> Dr. G.W. Wettstein, Ph.D.   Enjellic Systems Development, LLC.
> 4206 N. 19th Ave.           Specializing in information infra-structure
> Fargo, ND  58102            development.
> PH: 701-281-1686
> FAX: 701-281-3949           EMAIL: gr...@en...
> ------------------------------------------------------------
> ------------------
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