From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: James Bottomley <jejb@linux.vnet.ibm.com>
Cc: linux-security-module@vger.kernel.org,
tpmdd-devel@lists.sourceforge.net,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [tpmdd-devel] [PATCH RFC 0/4] RFC: in-kernel resource manager
Date: Tue, 3 Jan 2017 20:36:02 +0200 [thread overview]
Message-ID: <20170103183602.ar5typcvy2rx7cjs@intel.com> (raw)
In-Reply-To: <1483460095.2464.6.camel@linux.vnet.ibm.com>
On Tue, Jan 03, 2017 at 08:14:55AM -0800, James Bottomley wrote:
> On Tue, 2017-01-03 at 15:41 +0200, Jarkko Sakkinen wrote:
> > On Mon, Jan 02, 2017 at 09:26:58PM -0800, James Bottomley wrote:
> > > On Mon, 2017-01-02 at 13:40 -0800, James Bottomley wrote:
> > > > On Mon, 2017-01-02 at 21:33 +0200, Jarkko Sakkinen wrote:
> > > > > 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).
> > > > >
> > > > > This is a valid question and here's a longish explanation.
> > > > >
> > > > > In TPM2_GetCapability and maybe couple of other commands you
> > > > > can get handles in the response body. I do not want to have
> > > > > special cases in the kernel for response bodies because there
> > > > > is no a generic way to do the substitution. What's worse, new
> > > > > commands in the standard future revisions could have such
> > > > > commands requiring special cases. In addition, vendor specific
> > > > > commans could have handles in the response bodies.
> > > >
> > > > OK, in general I buy this ... what you're effectively saying is
> > > > that we need a non-RM interface for certain management type
> > > > commands.
> > > >
> > > > However, let me expand a bit on why I'm fretting about the non-RM
> > > > use case. Right at the moment, we have a single TPM device which
> > > > you use for access to the kernel TPM. The current tss2 just
> > > > makes direct use of this, meaning it has to have 0666
> > > > permissions. This means that any local user can simply DoS the
> > > > TPM by running us out of transient resources if they don't
> > > > activate the RM. If they get a connection always via the RM,
> > > > this isn't a worry. Perhaps the best way of fixing this is to
> > > > expose two separate device nodes: one raw to the TPM which we
> > > > could keep at 0600 and one with an always RM connection
> > > > which we can set to 0666. That would mean that access to the non
> > > > -RM connection is either root only or governed by a system set
> > > > ACL.
> > >
> > > OK, so I put a patch together that does this (see below). It all
> > > works nicely (with a udev script that sets the resource manager
> > > device to 0666):
> >
> > This is not yet a comment about this suggestion but I guess one thing
> > is clear: the stuff in tpm2-space.c and tpm-interface.c changes are
> > the thing that we can mostly agree on and the area of argumentation
> > is the user space interface to it?
>
> Agreed. As I've already said, the space and interface code is working
> well for me in production on my laptop.
>
> > Just thinking how to split up the non-RFC patch set. This was also
> > what Jason suggested if I understood his remark correctly.
>
> SUre ... let's get agreement on how we move forward first. How the
> patch is activated by the user has to be sorted out as well before it
> can go in, but it doesn't have to be the first thing we do. I'm happy
> to continue playing with the interfaces to see what works and what
> doesn't. My main current feedback is that I think separate devices
> works way better than an ioctl becuase the separate devices approach
> allows differing system policies for who accesses the RM backed TPM vs
> who accesses the raw one.
I think I see your point. I would rather name the device as tpms0 but
otherwise I think we could do it in the way you suggest...
> James
/Jarkko
next prev parent reply other threads:[~2017-01-03 18:36 UTC|newest]
Thread overview: 81+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-02 13:22 [PATCH RFC 0/4] RFC: in-kernel resource manager Jarkko Sakkinen
2017-01-02 13:22 ` [PATCH RFC 1/4] tpm: migrate struct tpm_buf to struct tpm_chip Jarkko Sakkinen
2017-01-02 21:01 ` Jason Gunthorpe
2017-01-03 0:57 ` Jarkko Sakkinen
2017-01-03 19:13 ` Jason Gunthorpe
2017-01-04 12:29 ` Jarkko Sakkinen
2017-01-02 13:22 ` [PATCH RFC 2/4] tpm: validate TPM 2.0 commands Jarkko Sakkinen
[not found] ` <OF8D508BD2.EAB22BFD-ON0025809E.0062B40C-8525809E.006356C3@notes.na.collabserv.com>
2017-01-04 18:19 ` [tpmdd-devel] " James Bottomley
2017-01-04 18:44 ` Jason Gunthorpe
2017-01-02 13:22 ` [PATCH RFC 3/4] tpm: export tpm2_flush_context_cmd Jarkko Sakkinen
2017-01-02 13:22 ` [PATCH RFC 4/4] tpm: add the infrastructure for TPM space for TPM 2.0 Jarkko Sakkinen
2017-01-02 21:09 ` Jason Gunthorpe
2017-01-03 0:37 ` Jarkko Sakkinen
2017-01-03 18:46 ` Jason Gunthorpe
2017-01-04 12:43 ` Jarkko Sakkinen
2017-01-03 19:16 ` Jason Gunthorpe
2017-01-04 12:45 ` Jarkko Sakkinen
[not found] ` <OF9C3EE9AE.65978870-ON0025809E.0061E7AF-8525809E.0061FFDA@notes.na.collabserv.com>
2017-01-09 22:11 ` [tpmdd-devel] " Jarkko Sakkinen
2017-01-02 16:36 ` [tpmdd-devel] [PATCH RFC 0/4] RFC: in-kernel resource manager James Bottomley
2017-01-02 19:33 ` Jarkko Sakkinen
2017-01-02 21:40 ` James Bottomley
2017-01-03 5:26 ` James Bottomley
2017-01-03 13:41 ` Jarkko Sakkinen
2017-01-03 16:14 ` James Bottomley
2017-01-03 18:36 ` Jarkko Sakkinen [this message]
2017-01-03 19:14 ` Jarkko Sakkinen
2017-01-03 19:34 ` James Bottomley
2017-01-03 21:54 ` Jason Gunthorpe
2017-01-04 12:58 ` Jarkko Sakkinen
2017-01-04 16:55 ` Jason Gunthorpe
2017-01-04 5:47 ` Andy Lutomirski
2017-01-04 13:00 ` Jarkko Sakkinen
2017-01-03 13:51 ` Jarkko Sakkinen
2017-01-03 16:36 ` James Bottomley
2017-01-03 18:40 ` Jarkko Sakkinen
2017-01-03 21:47 ` Jason Gunthorpe
2017-01-03 22:21 ` Ken Goldman
2017-01-03 23:20 ` Jason Gunthorpe
2017-01-03 22:39 ` James Bottomley
2017-01-04 0:17 ` Jason Gunthorpe
2017-01-04 0:29 ` James Bottomley
2017-01-04 0:56 ` Jason Gunthorpe
2017-01-04 12:50 ` Jarkko Sakkinen
2017-01-04 14:53 ` James Bottomley
2017-01-04 18:31 ` Jason Gunthorpe
2017-01-04 18:57 ` James Bottomley
2017-01-04 19:24 ` Jason Gunthorpe
2017-01-04 12:48 ` Jarkko Sakkinen
2017-01-03 21:32 ` Jason Gunthorpe
2017-01-03 22:03 ` James Bottomley
2017-01-05 15:52 ` Fuchs, Andreas
2017-01-05 17:27 ` Jason Gunthorpe
2017-01-05 18:06 ` James Bottomley
2017-01-06 8:43 ` Andreas Fuchs
2017-01-05 18:33 ` James Bottomley
2017-01-05 19:20 ` Jason Gunthorpe
2017-01-05 19:55 ` James Bottomley
2017-01-05 22:21 ` Jason Gunthorpe
2017-01-05 22:58 ` James Bottomley
2017-01-05 23:50 ` Jason Gunthorpe
2017-01-06 0:36 ` James Bottomley
2017-01-06 8:59 ` Andreas Fuchs
2017-01-06 19:10 ` Jason Gunthorpe
2017-01-06 19:02 ` Jason Gunthorpe
2017-01-10 19:03 ` Ken Goldman
2017-01-09 22:39 ` [tpmdd-devel] " Jarkko Sakkinen
2017-01-11 10:03 ` Andreas Fuchs
2017-01-04 16:12 Dr. Greg Wettstein
2017-01-09 23:16 ` Jarkko Sakkinen
2017-01-10 19:29 ` Ken Goldman
2017-01-11 11:36 ` Jarkko Sakkinen
2017-01-10 20:05 ` Jason Gunthorpe
2017-01-11 10:00 ` Andreas Fuchs
2017-01-11 18:03 ` Jason Gunthorpe
2017-01-11 18:27 ` Stefan Berger
2017-01-11 19:18 ` Jason Gunthorpe
2017-01-11 11:34 ` Jarkko Sakkinen
2017-01-11 15:39 ` James Bottomley
2017-01-11 17:56 ` Jason Gunthorpe
2017-01-11 18:25 ` James Bottomley
2017-01-11 19:04 ` Jason Gunthorpe
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