linux-kernel - Re: [tpmdd-devel] [PATCH RFC 0/4] RFC: in-kernel resource manager

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Date:   Tue, 3 Jan 2017 14:32:34 -0700
From:   Jason Gunthorpe <jgunthorpe@...idianresearch.com>
To:     James Bottomley <James.Bottomley@...senPartnership.com>
Cc:     Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
        tpmdd-devel@...ts.sourceforge.net,
        linux-security-module@...r.kernel.org,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [tpmdd-devel] [PATCH RFC 0/4] RFC: in-kernel resource manager

On Mon, Jan 02, 2017 at 08:36:20AM -0800, James Bottomley wrote:
> On Mon, 2017-01-02 at 15:22 +0200, Jarkko Sakkinen wrote:
> > This patch set adds support for TPM spaces that provide a context
> > for isolating and swapping transient objects. This patch set does
> > not yet include support for isolating policy and HMAC sessions but
> > it is trivial to add once the basic approach is settled (and that's
> > why I created an RFC patch set).
> 
> The approach looks fine to me.  The only basic query I have is about
> the default: shouldn't it be with resource manager on rather than off? 
>  I can't really think of a use case that wants the RM off (even if
> you're running your own, having another doesn't hurt anything, and it's
> still required to share with in-kernel uses).

I haven't looked too closely at TPM 2.0 stuff, but at least for 1.2 we
should have a kernel white-list of allowed commands within a RM
context, so having the RM on by default would break all of the user
space.

I really think the only way forward here is a new char dev that is
safe for unprivileged/concurrent use and migrate the user space stack
to use it instead.

> And with that, I've TPM 2 enabled both gnome-keyring and openssl:
> 
> https://build.opensuse.org/package/show/home:jejb1:Tumbleweed/gnome-keyring
> https://build.opensuse.org/package/show/home:jejb1:Tumbleweed/openssl_tpm_engine
 
> I'm running them in production on my day to day laptop and so far
> everything's working nicely (better than 1.2, in fact, since tcsd
> periodically crashes necessitating a restart of everything).

You granted your unprivileged user access to /dev/tpm0 then? FYI I
think that is a dangerous idea..

Jason