From: Roberts, William C <william.c.roberts at intel.com>
To: tpm2@lists.01.org
Subject: [tpm2] Re: some questions about Identity
Date: Wed, 15 Jan 2020 14:34:25 +0000 [thread overview]
Message-ID: <476DC76E7D1DF2438D32BFADF679FC5649E66B9F@ORSMSX101.amr.corp.intel.com> (raw)
In-Reply-To: fec9ef06-827c-8451-cfb3-4bd79a04e682@uvensys.de
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> -----Original Message-----
> From: Steffen [mailto:s.schwebel(a)uvensys.de]
> Sent: Wednesday, January 15, 2020 2:37 AM
> To: tpm2(a)lists.01.org
> Subject: [tpm2] Re: some questions about Identity
>
> Actually, I have a follow up question.
>
> If I understand the documentation correctly, I should always be able to generate
> the EK via tpm2_createek. That should (can?) never change.
Generally yes, see my other email about the changeeps command.
>
> So, upon initial deployment, first check and store EK.
>
> tpm2_createek -G rsa -u ek.pub -c key.ctx
The tool is hardcoded to the EK template, most manufacturers store the template in an NV index as well:
https://trustedcomputinggroup.org/wp-content/uploads/TCG_IWG_Credential_Profile_EK_V2.1_R13.pdf
The -t switch for tpm2_createek will interrogate those NV indices. I think the man page is wrong, it shows
It also taking a FILE argument, but the code is written that way.
Bug:
https://github.com/tpm2-software/tpm2-tools/issues/1886
>
> tpm2_getekcertificate -X -o ECcert.bin -u ek.pub \
> https://tpm.manufacturer.com/ekcertserver/
Not all manufacturers store EK certificates online, and that tool is set for the intel method of
URL retrieval AFAICT. We had a conversation about this before with mdemsky but I am not
Sure what the end result was. I think it was that we need to make the tool better and handle
Non URL EK Cert retrieval.
The spec https://trustedcomputinggroup.org/wp-content/uploads/TCG_IWG_Credential_Profile_EK_V2.1_R13.pdf
Section 2.2.1.9 show that certain NV indices are reserved for EK Cert storage, so it could be lurking in there.
Bug:
https://github.com/tpm2-software/tpm2-tools/issues/1885
>
>
> Right?
Pretty much. But remember that the EK is policy bound to the Endorsement Hierarchy password, so
To use it you need to authenticate via a policy session using the policy secret command. Examples
Of how to use the policy secret command are in the manpage for the tool:
https://github.com/tpm2-software/tpm2-tools/blob/master/man/tpm2_policysecret.1.md
Dan Oliver actually posted a ticket on this, I have more detail in that:
https://github.com/tpm2-software/tpm2-tools/issues/1884
next reply other threads:[~2020-01-15 14:34 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-15 14:34 Roberts, William C [this message]
-- strict thread matches above, loose matches on Subject: below --
2020-01-17 8:29 [tpm2] Re: some questions about Identity s.schwebel
2020-01-16 22:31 Roberts, William C
2020-01-16 18:42 nicolasoliver03
2020-01-16 11:34 s.schwebel
2020-01-15 22:22 Desai, Imran
2020-01-15 20:53 Roberts, William C
2020-01-15 19:33 Desai, Imran
2020-01-15 18:18 Roberts, William C
2020-01-15 17:17 nicolasoliver03
2020-01-15 8:36 Steffen
2020-01-14 16:00 Steffen
2020-01-09 18:43 Niklas Andersson
2020-01-09 9:28 Fuchs, Andreas
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