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Message-ID: <1597597699.8344.11.camel@linux.ibm.com>
Subject: Re: [PATCH RESEND] docs: update trusted-encrypted.rst
From:   James Bottomley <jejb@linux.ibm.com>
Reply-To: jejb@linux.ibm.com
To:     Coly Li <colyli@suse.de>, Stefan Berger <stefanb@linux.ibm.com>
Cc:     keyrings@vger.kernel.org, linux-kernel@vger.kernel.org,
        Dan Williams <dan.j.williams@intel.com>,
        Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
        Mimi Zohar <zohar@linux.ibm.com>
Date:   Sun, 16 Aug 2020 10:08:19 -0700
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         <cf667ea0-dab7-a242-886c-938582c62ff6@linux.ibm.com>
         <096636f4-a928-dd00-dba6-216651c3d63b@suse.de>
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On Mon, 2020-08-17 at 01:01 +0800, Coly Li wrote:
> On 2020/8/17 00:06, Stefan Berger wrote:
> > On 8/15/20 3:51 AM, Coly Li wrote:
[...]
> > >     Usage::
> > > @@ -115,7 +114,7 @@ append 'keyhandle=0x81000001' to statements
> > > between quotes, such as
> > 
> > 
> > A note in this file states this:
> > 
> > Note: When using a TPM 2.0 with a persistent key with handle
> > 0x81000001, append 'keyhandle=0x81000001' to statements between
> > quotes, such as "new 32 keyhandle=0x81000001".
> > 
> > Now if someone was (still) interested in TPM 1.2 then the below
> > changes you are proposing wouldn't work for them. Maybe you should
> > adapt the note to state that these keyhandle=... should be removed
> > for the TPM 1.2 case.
> > 
> 
> I agree. Indeed I have no idea why number 0x81000001 is used, and I
> don't have practice experience with TPM 1.2. Now the purpose of this
> patch accomplished: experts response and confirm my guess :-)

It was the conventional persistent value for the RSA 2048 version of
the primary storage seed.  Originally the PC spec required the
manufacturer provision this on all TPM 2.0 based PC class systems. 
Unfortunately in spite of it being in the Windows Hardware guide no
manufacturer ever did, meaning you either have to create it yourself or
do something different.  Because of usability problems, every consumer
of TPM key function has opted to do something different, namely derive
the EC primary if no parent is specified.

James