[tpm2] Re: Re-provision TPM

at rubynerd <x at rubynerd.net>
Newsgroups dev.linux.lists.tpm2
Message-ID <CAFmPt0qQbjL+Wd0HOUJ1O50GtGNErBgdAx_VZOt+7yCt7SxXLg@mail.gmail.com>
Hi Anthony,

I'm also new to the tpm2-tools project, and whilst I cannot advise on most
of the asks in your email, I can confirm the tpm2_takeownership command was
changed to tpm2_changeauth, which offers similar functionality.

Further information is available in the changelog:
https://github.com/tpm2-software/tpm2-tools/blame/master/doc/CHANGELOG.md#L867-L872

There's quite a bit of movement between what's currently in source control
and the snippets floating around on StackOverflow, the changelog is a
really good resource for reconciling these. One thing to note: if you're
building this from source, the commands have changed from
"tpm2_commandname" to "tpm2 commandname", which was another pitfall I fell
into during my explorations.

Regarding the specifics of EKs and the differences/functionality of the
APIs themselves, I'm afraid I'm woefully out of my depth!

Hope this helps,
Luke

On Wed, Jun 30, 2021 at 11:07 AM Anthony Arrascue <AArrascue(a)neuroloop.de>
wrote:

> A way of re-provisioning (on a different OS image) that worked for me is
> the following:
>
>
>
> *tpm2_startup*
>
> #This clears the persistent storage
>
> *tpm2_clear*
>
> #To change profile from ECC to RSA
>
> *sed -i 's/"profile_name": "P_ECCP256SHA256"/"profile_name":
> "P_RSA2048SHA256"/g' /usr/local/etc/tpm2-tss/fapi-config.json*
>
> #Delete existing keystores
>
> *rm -rf ~/.local/share/tpm2-tss/user/keystore*
>
> *rm -rf /usr/local/var/lib/tpm2-tss/system/keystore*
>
> #Before we provision we need to generate an EK
>
> *tpm2_createprimary -C e -g sha256 -G rsa -c endorsementprimary.ctx *
>
> *tpm2_create -C endorsementprimary.ctx -g sha256 -G rsa -u rsak.pub -r
> rsak.priv*
>
> *tpm2_load -C endorsementprimary.ctx -u rsak.pub -r rsak.priv -n rsak.name
> <http://rsak.name> -c rsak.ctx*
>
> *tpm2_evictcontrol -c rsak.ctx 0x81010001*
>
> *tss2_provision*
>
>
>
> Without the tpm2_createprimary I would get an error when I use
> tss2_provision (something like “key cannot be signed”. I cannot remember
> the error message, but it contained the word EK).
>
>
>
> Some questions that came to my mind:
>
>    1. Can all of this be done using only Fapi (no tpm2 commands)
>    2. Why is generating an EK required for provisioning? (which
>    documentation describes this step)
>    3. Previous versions of the tpm2-tools had also a *tpm2_takeownership*.
>    What happened with it and how to provision with owner’s authorization?
>
>
>
> Thank you very much for your comments.
>
> Best,
>
> Anthony
>
>
>
>
>
>
>
>
>
>
>
> *From:* Anthony Arrascue
> *Sent:* Tuesday, 1 June 2021 19:18
> *To:* 'tpm2(a)lists.01.org' <tpm2(a)lists.01.org>
> *Subject:* Re-provision TPM
>
>
>
> Hello,
>
>
>
> I am learning about the TSS and TPM techonologies.
> I have provisioned the TPM with the default settings, which means I am now
> using the ECC profile (P_ECCP256SHA256).
>
> However, encryption was a requirement I needed to fulfill. I just didn't
> know that ECC encryption is currently not supported and now I realize RSA
> would be a better fit for me.
>
> So here is my question:
>
>    - I see there is another profile in
>    /usr/local/etc/tpm2-tss/fapi-profiles, namely P_RSA2048SHA256.json. Is
>    there a way I can encrypt using the RSA profile instead of the ECC one? I
>    tried to re-run tss2_provision, after setting it in fapi-config.json, but
>    it seems this is not the way to proceed. I get the message that the TPM has
>    been already provisioned. What is the correct way of "changing" profile? Is
>    it even possible or do I need to reset the TPM?
>
> Thank you for your help.
>
> Anthony Arrascue
>
>
> _______________________________________________
> tpm2 mailing list -- tpm2(a)lists.01.org
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attachment.htm (text/html, 8.5 KB)
<div dir="ltr">Hi Anthony,<div><br></div><div>I&#39;m also new to the tpm2-tools project, and whilst I cannot advise on most of the asks in your email, I can confirm the tpm2_takeownership command was changed to tpm2_changeauth, which offers similar functionality.</div><div><br></div><div>Further information is available in the changelog: <a href="https://github.com/tpm2-software/tpm2-tools/blame/master/doc/CHANGELOG.md#L867-L872">https://github.com/tpm2-software/tpm2-tools/blame/master/doc/CHANGELOG.md#L867-L872</a></div><div><br></div><div>There&#39;s quite a bit of movement between what&#39;s currently in source control and the snippets floating around on StackOverflow, the changelog is a really good resource for reconciling these. One thing to note: if you&#39;re building this from source, the commands have changed from &quot;tpm2_commandname&quot; to &quot;tpm2 commandname&quot;, which was another pitfall I fell into during my explorations.</div><div><br></div><div>Regarding the specifics of EKs and the differences/functionality of the APIs themselves, I&#39;m afraid I&#39;m woefully out of my depth!</div><div><br></div><div>Hope this helps,</div><div>Luke</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Jun 30, 2021 at 11:07 AM Anthony Arrascue &lt;<a href="mailto:[email protected]">[email protected]</a>&gt; wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">





<div lang="en-DE" style="overflow-wrap: break-word;">
<div class="gmail-m_2982244829317484457WordSection1">
<p class="MsoNormal"><span lang="EN-US">A way of re-provisioning (on a different OS image) that worked for me is the following:<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal"><b><span lang="EN-US">tpm2_startup<u></u><u></u></span></b></p>
<p class="MsoNormal"><span lang="EN-US">#This clears the persistent storage<u></u><u></u></span></p>
<p class="MsoNormal"><b><span lang="EN-US">tpm2_clear<u></u><u></u></span></b></p>
<p class="MsoNormal"><span lang="EN-US">#To change profile from ECC to RSA<u></u><u></u></span></p>
<p class="MsoNormal"><b><span lang="EN-US">sed -i &#39;s/&quot;profile_name&quot;: &quot;P_ECCP256SHA256&quot;/&quot;profile_name&quot;: &quot;P_RSA2048SHA256&quot;/g&#39; /usr/local/etc/tpm2-tss/fapi-config.json<u></u><u></u></span></b></p>
<p class="MsoNormal"><span lang="EN-US">#Delete existing keystores<u></u><u></u></span></p>
<p class="MsoNormal"><b><span lang="EN-US">rm -rf ~/.local/share/tpm2-tss/user/keystore<u></u><u></u></span></b></p>
<p class="MsoNormal"><b><span lang="EN-US">rm -rf /usr/local/var/lib/tpm2-tss/system/keystore<u></u><u></u></span></b></p>
<p class="MsoNormal"><span lang="EN-US">#Before we provision we need to generate an EK<u></u><u></u></span></p>
<p class="MsoNormal"><b><span lang="EN-US">tpm2_createprimary -C e -g sha256 -G rsa -c endorsementprimary.ctx
<u></u><u></u></span></b></p>
<p class="MsoNormal"><b><span lang="EN-US">tpm2_create -C endorsementprimary.ctx -g sha256 -G rsa -u rsak.pub -r rsak.priv<u></u><u></u></span></b></p>
<p class="MsoNormal"><b><span lang="EN-US">tpm2_load -C endorsementprimary.ctx -u rsak.pub -r rsak.priv -n <a href="http://rsak.name" target="_blank">rsak.name</a> -c rsak.ctx<u></u><u></u></span></b></p>
<p class="MsoNormal"><b><span lang="EN-US">tpm2_evictcontrol -c rsak.ctx 0x81010001<u></u><u></u></span></b></p>
<p class="MsoNormal"><b><span lang="EN-US">tss2_provision<u></u><u></u></span></b></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">Without the tpm2_createprimary I would get an error when I use tss2_provision (something like “key cannot be signed”. I cannot remember the error message, but it contained the word EK).<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">Some questions that came to my mind: <u></u>
<u></u></span></p>
<ol style="margin-top:0cm" start="1" type="1">
<li class="gmail-m_2982244829317484457MsoListParagraph" style="margin-left:0cm"><span lang="EN-US">Can all of this be done using only Fapi (no tpm2 commands)<u></u><u></u></span></li><li class="gmail-m_2982244829317484457MsoListParagraph" style="margin-left:0cm"><span lang="EN-US">Why is generating an EK required for provisioning? (which documentation describes this step)<u></u><u></u></span></li><li class="gmail-m_2982244829317484457MsoListParagraph" style="margin-left:0cm"><span lang="EN-US">Previous versions of the tpm2-tools had also a
<b>tpm2_takeownership</b>. What happened with it and how to provision with owner’s authorization?<u></u><u></u></span></li></ol>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">Thank you very much for your comments.<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">Best,<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">Anthony<u></u><u></u></span></p>
<p class="MsoNormal"><b><span lang="EN-US"><u></u> <u></u></span></b></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<div style="border-top:none;border-right:none;border-bottom:none;border-left:1.5pt solid blue;padding:0cm 0cm 0cm 4pt">
<div>
<div style="border-right:none;border-bottom:none;border-left:none;border-top:1pt solid rgb(225,225,225);padding:3pt 0cm 0cm">
<p class="MsoNormal"><b><span lang="EN-US">From:</span></b><span lang="EN-US"> Anthony Arrascue
<br>
<b>Sent:</b> Tuesday, 1 June 2021 19:18<br>
<b>To:</b> &#39;<a href="mailto:[email protected]" target="_blank">[email protected]</a>&#39; &lt;<a href="mailto:[email protected]" target="_blank">[email protected]</a>&gt;<br>
<b>Subject:</b> Re-provision TPM<u></u><u></u></span></p>
</div>
</div>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal"><span lang="DE">Hello,<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="DE"><u></u> <u></u></span></p>
<p class="MsoNormal" style="margin-bottom:12pt;background:white"><span lang="en-DE" style="font-size:10.5pt;font-family:&quot;Segoe UI&quot;,sans-serif;color:rgb(36,41,46)">I am learning about the TSS and TPM techonologies.<br>
I have provisioned the TPM with the default settings, which means I am now using the ECC profile (P_ECCP256SHA256).<u></u><u></u></span></p>
<p class="MsoNormal" style="margin-bottom:12pt;background:white"><span lang="en-DE" style="font-size:10.5pt;font-family:&quot;Segoe UI&quot;,sans-serif;color:rgb(36,41,46)">However, encryption was a requirement I needed to fulfill. I just didn&#39;t
 know that ECC encryption is currently not supported and now I realize RSA would be a better fit for me.<u></u><u></u></span></p>
<p class="MsoNormal" style="margin-bottom:12pt;background:white"><span lang="en-DE" style="font-size:10.5pt;font-family:&quot;Segoe UI&quot;,sans-serif;color:rgb(36,41,46)">So here is my question:<u></u><u></u></span></p>
<ul type="disc">
<li class="MsoNormal" style="color:rgb(36,41,46);background:white">
<span lang="en-DE" style="font-size:10.5pt;font-family:&quot;Segoe UI&quot;,sans-serif">I see there is another profile in /usr/local/etc/tpm2-tss/fapi-profiles, namely P_RSA2048SHA256.json. Is there a way I can encrypt using the RSA profile
 instead of the ECC one? I tried to re-run tss2_provision, after setting it in fapi-config.json, but it seems this is not the way to proceed. I get the message that the TPM has been already provisioned. What is the correct way of &quot;changing&quot; profile? Is it even
 possible or do I need to reset the TPM?<u></u><u></u></span></li></ul>
<p class="MsoNormal" style="background:white"><span lang="en-DE" style="font-size:10.5pt;font-family:&quot;Segoe UI&quot;,sans-serif;color:rgb(36,41,46)">Thank you for your help.</span><span lang="en-DE"><u></u><u></u></span></p>
<p class="MsoNormal"><span lang="DE" style="font-size:10pt;color:black">Anthony Arrascue<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="en-DE"><u></u> <u></u></span></p>
</div>
</div>
</div>

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