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From:   Evan Green <evgreen@chromium.org>
Date:   Wed, 24 Aug 2022 10:34:10 -0700
Message-ID: <CAE=gft48Tg6NnEUqfM-n1eOT3qa35dtowQGYCL3sbYBmr_Wm_w@mail.gmail.com>
Subject: Re: [PATCH v2 04/10] security: keys: trusted: Allow storage of PCR
 values in creation data
To:     list.lkml.keyrings@me.benboeckel.net
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Gwendal Grignou <gwendal@chromium.org>,
        Eric Biggers <ebiggers@kernel.org>,
        Matthew Garrett <mgarrett@aurora.tech>,
        Jarkko Sakkinen <jarkko@kernel.org>, zohar@linux.ibm.com,
        linux-integrity@vger.kernel.org, Pavel Machek <pavel@ucw.cz>,
        apronin@chromium.org, Daniil Lunev <dlunev@google.com>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Linux PM <linux-pm@vger.kernel.org>,
        Jonathan Corbet <corbet@lwn.net>,
        "James E.J. Bottomley" <jejb@linux.ibm.com>,
        Matthew Garrett <matthewgarrett@google.com>,
        Matthew Garrett <mjg59@google.com>,
        David Howells <dhowells@redhat.com>,
        James Morris <jmorris@namei.org>,
        Paul Moore <paul@paul-moore.com>,
        "Serge E. Hallyn" <serge@hallyn.com>, keyrings@vger.kernel.org,
        "open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
        linux-security-module@vger.kernel.org
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On Wed, Aug 24, 2022 at 4:56 AM Ben Boeckel <me@benboeckel.net> wrote:
>
> On Tue, Aug 23, 2022 at 15:25:20 -0700, Evan Green wrote:
> > diff --git a/Documentation/security/keys/trusted-encrypted.rst b/Documentation/security/keys/trusted-encrypted.rst
> > index 0bfb4c33974890..dc9e11bb4824da 100644
> > --- a/Documentation/security/keys/trusted-encrypted.rst
> > +++ b/Documentation/security/keys/trusted-encrypted.rst
> > @@ -199,6 +199,10 @@ Usage::
> >         policyhandle= handle to an authorization policy session that defines the
> >                       same policy and with the same hash algorithm as was used to
> >                       seal the key.
> > +       creationpcrs= hex integer representing the set of PCR values to be
> > +                     included in the PCR creation data. The bit corresponding
> > +                  to each PCR should be 1 to be included, 0 to be ignored.
> > +                  TPM2 only.
>
> There's inconsistent whitespace here. Given the context, I suspect the
> tabs should be expanded to spaces.
>
> As for the docs themselves, this might preferrably mention how large
> this is supposed to be. It seems to be limited to 32bits by the code.
> What happens if fewer are provided? More? Will there always be at most
> 32 PCR values? Also, how are the bits interpreted? I presume bit 0 is
> for PCR value 0?

Makes sense, I'll pin down the specification a bit better here and fix
up the spacing.

>
> Thanks for including docs.

Thanks for looking at them!

-Evan