RE: [PATCH] docs: Extend trusted keys documentation for TPM 2.0

[Roberts, William C]

> -----Original Message-----
> From: Joshua Lock [mailto:joshua.g.lock@xxxxxxxxxxxxxxx]
> Sent: Tuesday, November 6, 2018 8:15 AM
> To: Jerry Snitselaar <jsnitsel@xxxxxxxxxx>; Stefan Berger
> <stefanb@xxxxxxxxxxxxx>; keyrings@xxxxxxxxxxxxxxx; linux-
> integrity@xxxxxxxxxxxxxxx; zohar@xxxxxxxxxxxxx; jejb@xxxxxxxxxxxxx;
> Alexander.Levin@xxxxxxxxxxxxx; jmorris@xxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx
> Cc: Roberts, William C <william.c.roberts@xxxxxxxxx>
> Subject: Re: [PATCH] docs: Extend trusted keys documentation for TPM 2.0
> 
> On Tue, 2018-11-06 at 09:00 -0700, Jerry Snitselaar wrote:
> > On Mon Nov 05 18, Jerry Snitselaar wrote:
> > > On Fri Oct 19 18, Stefan Berger wrote:
> > > > Extend the documentation for trusted keys with documentation for
> > > > how to set up a key for a TPM 2.0 so it can be used with a TPM 2.0
> > > > as well.
> > > >
> > > > Signed-off-by: Stefan Berger <stefanb@xxxxxxxxxxxxx>
> > > > Reviewed-by: Mimi Zohar <zohar@xxxxxxxxxxxxx>
> > > > ---
> > > > .../security/keys/trusted-encrypted.rst       | 31
> > > > ++++++++++++++++++-
> > > > 1 file changed, 30 insertions(+), 1 deletion(-)
> > > >
> > > > diff --git a/Documentation/security/keys/trusted-encrypted.rst
> > > > b/Documentation/security/keys/trusted-encrypted.rst
> > > > index 3bb24e09a332..6ec6bb2ac497 100644
> > > > --- a/Documentation/security/keys/trusted-encrypted.rst
> > > > +++ b/Documentation/security/keys/trusted-encrypted.rst
> > > > @@ -18,10 +18,33 @@ integrity verifications match.  A loaded
> > > > Trusted Key can be updated with new when the kernel and initramfs
> > > > are updated.  The same key can have many saved blobs under
> > > > different PCR values, so multiple boots are easily supported.
> > > >
> > > > +TPM 1.2
> > > > +-------
> > > > +
> > > > By default, trusted keys are sealed under the SRK, which has the
> > > > default authorization value (20 zeros).  This can be set at
> > > > takeownership time with the trouser's utility: "tpm_takeownership
> > > > -u -z".
> > > >
> > > > +TPM 2.0
> > > > +-------
> > > > +
> > > > +The user must first create a storage key and make it persistent,
> > > > so the key is
> > > > +available after reboot. This can be done using the following
> > > > commands.
> > > > +
> > > > +With the IBM TSS 2 stack::
> > > > +
> > > > +  #> tsscreateprimary -hi o -st
> > > > +  Handle 80000000
> > > > +  #> tssevictcontrol -hi o -ho 80000000 -hp 81000001
> > > > +
> > > > +Or with the Intel TSS 2 stack::
> > > > +
> > > > +  #> tpm2_createprimary --hierarchy o -G rsa2048 -o key.ctxt
> > > > + [...]
> > > > +  handle: 0x800000FF
> > > > +  #> tpm2_evictcontrol -c key.ctxt -p 0x81000001
> > > > +  persistentHandle: 0x81000001
> > > > +
> > >
> > > Is that the correct option for tpm2_evictcontrol? What I'm seeing in
> > > the versions I have is -S or -persistent= for specifying the
> > > persistent handle.
> > >
> > > Other than that looks good to me.
> >
> > William, is the above correct?
> 
> We're changing some of the options in master ahead of our next major release,
> the -p/--persistent option is correct for that branch and the eventual 4.X series.

LGTM.

Also if you specify --help=no-man it will dump a short summary to stdout (master only) which is useful.

> 
> Regards,
> Joshua
> 
> > >
> > > > Usage::
> > > >
> > > >    keyctl add trusted name "new keylen [options]" ring @@ -30,7
> > > > +53,9 @@ Usage::
> > > >    keyctl print keyid
> > > >
> > > >    options:
> > > > -       keyhandle=    ascii hex value of sealing key default
> > > > 0x40000000 (SRK)
> > > > +       keyhandle=    ascii hex value of sealing key
> > > > +                       TPM 1.2: default 0x40000000 (SRK)
> > > > +                       TPM 2.0: no default; must be passed every
> > > > time
> > > >       keyauth=	     ascii hex auth for sealing key default
> > > > 0x00...i
> > > >                     (40 ascii zeros)
> > > >       blobauth=     ascii hex auth for sealed data default
> > > > 0x00...
> > > > @@ -84,6 +109,10 @@ Examples of trusted and encrypted key usage:
> > > >
> > > > Create and save a trusted key named "kmk" of length 32 bytes::
> > > >
> > > > +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".
> > > > +
> > > >    $ keyctl add trusted kmk "new 32" @u
> > > >    440502848
> > > >
> > > > --
> > > > 2.17.2
> > > >