On Wed, 2020-02-05 at 14:41 +0000, LE ROY Olivier - Contractor wrote:
> Hi Lukasz,
>
> > What exactly did you add to that policy in lcp-gen2 tool? LCP is a
> policy dedicated for SINIT, not for TBOOT.
> > The another approach is to create separate index for VLP (0x01C10131)
> and put VLP there.
>
> I understand better why there weren't any log for the LCP_ANY policy and why
> tboot expects a VLP.
> Thanks for the comprehensive answer.
> I am still learning to implement policies in TPM2.0, trying to transpose what
> was done in a previous TPM1.2 based project.
>
> > What do mean "doesn't seem to understand it"? With LCP_ANY SINIT will
> allow any MLE to be executed.
>
> I was following the recommendation to start with something simple, i.e.
> LCP_ANY.
> Presently, I am trying a list policy, with an MLE element which hash is the
> tboot.gz hash, to implement a VLP at 0x01c10131.
>
> TBOOT logs are as follows:
> TBOOT: reading Verified Launch Policy from TPM NV...
> TBOOT: :70 bytes read
> TBOOT: policy:
> TBOOT: unsupported version (1)
> TBOOT: :reading failed
> TBOOT: reading Launch Control Policy from TPM NV...
> TBOOT: :70 bytes read
> TBOOT: :reading failed
> TBOOT: failed to read policy from TPM NV, using default
> TBOOT: policy:
> TBOOT: version: 2
>
> The policy was created using lcp-gen2 from tboot-1.9.9 python tools
> (tboot-1.9.11 has the same results).
> Do you have a hint why the generated policy has "version (1)" while tboot
> expects a version: 2?
>
> Regards,
>
> Olivier
>
MLE element goes to LCP and is consumed by SINIT, not TBOOT. You can't
provision VLP index with LCP.
To create VLP you have to use tb_polgen tool. Here is an example:
# create policy
tb_polgen --create --ctrl 0x00 --type continue vl.pol
# add kernel and its cmdline hash, extend PCR19
tb_polgen --add --num 0 --pcr 19 --hash image --cmdline "..." \
--image bzImage
# add initrd hash, extend PCR20
tb_polgen --add --num 1 --pcr 20 --hash image --cmdline "" \
--image initrd.img
If you want to create policy with MLE element you have to use lcp-gen2
tool and provision it to LCP index. But as I said, TBOOT has nothing to
do with it, you should not expect that TBOOT will measure itself :)
Thanks,
Lukasz
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