From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Cc: linux-security-module@vger.kernel.org,
tpmdd-devel@lists.sourceforge.net,
Andy Lutomirski <luto@kernel.org>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [tpmdd-devel] [PATCH RFC 0/4] RFC: in-kernel resource manager
Date: Wed, 04 Jan 2017 10:57:51 -0800 [thread overview]
Message-ID: <1483556271.2561.50.camel@HansenPartnership.com> (raw)
In-Reply-To: <20170104183125.GC783@obsidianresearch.com>
On Wed, 2017-01-04 at 11:31 -0700, Jason Gunthorpe wrote:
> On Wed, Jan 04, 2017 at 06:53:03AM -0800, James Bottomley wrote:
>
> > > > But this is not trousers, this is an in-kernel 0666 char dev
> > > > that will be active on basically every Linux system with a TPM.
> > > > I think we have a duty to be very conservative here.
> >
> > Just to note on this that trousers *is* effectively an 0666 kernel
> > device: all tcsd does is run with root privileges on the real
> > /dev/tpm0 and mediate the calls. It doesn't seem to police them at
> > all.
>
> That may be, but IHMO trousers is simply not relevant. Real systems
> do not seem to use trousers. I don't use it. Google doesn't use it.
> You report it is crashy.
>
> To me it just doesn't represent a reasonable way to use the TPM
> hardware.
It basically represents the only current way until there's a new API,
so all our current key handling tools use it. Given how I slammed it
in Plumbers, I'd be the last one to defend its actual API as usable ...
we just don't have another (yet).
> > For localities, assuming they can have real meaning in terms of the
> > protection model, I think one device per locality is better than an
> > ioctl because device policy is settable in underspace via the UNIX
> > ACL and hence locality policy is too.
>
> Yes.
>
> > I also think the command filter actually needs more thought. Right
> > at the moment, if we go with the current proposals, the kernel will
> > create two devices: /dev/tpm<n> and /dev/tpms<n>. By default
> > they'll both be root owned and 0600, so the current patch
> > adequately protects the TPM.
>
> Yes, but, considering the goals here I'd rather see the default
> kernel permissions for tpms be 0666 ....
>
> You are doing all this work to get the user space side in shape, I'd
> like to see matching kernel support. To me that means out-of-the-box
> a user can just use your plugins, the plugins will access /dev/tmps
> and everything will work fine for RSA key storage.
Actually, not necessarily; you're not considering the setup issue:
right at the moment users get delivered TPMs mostly in the cleared
state (thankfully they no longer have to clear via bios). So the first
thing a new user has to do is set all the authorizations and create an
SRK equivalent primary object at 0x81000001. I think in the interests
of best practice we want to make that as easy as possible; saying they
have to do this as root and use a different device is problematic.
You can say they don't have to use a different device because the
filter can be lifted for root, but then how do I lock down root apps
for this untrusted root setup secure boot has going on?
I suppose we could use TPMA_PERMANENT for this. The first three bits
indicate whether the authorizations are set, so if they're all clear,
we can assume an unowned TPM and lift the filter? A sort of trust on
first use model.
James
next prev parent reply other threads:[~2017-01-04 18:58 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
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 [this message]
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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