From: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
To: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Cc: tpmdd-devel@lists.sourceforge.net,
Leonidas Da Silva Barbosa <leosilva@linux.vnet.ibm.com>,
linux-kernel@vger.kernel.org, Rajiv Andrade <mail@srajiv.net>,
Sirrix AG <tpmdd@sirrix.com>
Subject: Re: [tpmdd-devel] [PATCH 09/13] tpm: Pull everything related to sysfs into tpm-sysfs.c
Date: Mon, 23 Sep 2013 16:23:24 -0600 [thread overview]
Message-ID: <20130923222324.GA9533@obsidianresearch.com> (raw)
In-Reply-To: <5240BA0E.3000304@tycho.nsa.gov>
On Mon, Sep 23, 2013 at 06:00:46PM -0400, Daniel De Graaf wrote:
> In a PC client TPM, normal OS code (as opposed to firmware or microcode)
> is already restricted to locality 0-2. It may make sense to restrict
> locality 2 to the kernel, which would allow an in-kernel TPM seal
> command to be able to bind data so that userspace cannot unseal it.
> However, only allowing localities 0 and 1 to userspace may be too
> restrictive if userspace also wishes to use locality for separation,
> since locality 1 does not have the ability to reset any PCRs that
> locality 0 cannot also reset.
> The kernel could reserve only locality 1 for its own use, giving it the
> ability to seal data but not interfering with the ability to reset PCRs.
> This would be my preference, although it is less intuitive to allow code
> of lower privilege (userspace) to control the higher numbered locality
> 2.
This matches my vague understanding (we don't use localities here)
>> Perhaps a .config option would be useful to allow the system designer to
>> choose what, if any, locality to reserve for kernel use?
A runtime sysfs seems reasonable..
Would:
user_default_locality
kernel_default_locality
user_allowed_localities (bitmask)
supported_localities (bitmask)
a GET_LOCALITY/SET_LOCALITY IOCTL to change localities of an open'd
/dev/tpmX
Do the job?
At first glance anyhow. I wonder what in-kernel users would be
impacted by localities..
Any thoughts on root vs not-root? Would middelware want to use
localities?
Do you know anyone on the userspace SW side who could look at this?
Jason
next prev parent reply other threads:[~2013-09-23 22:23 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-23 18:14 [PATCH 00/13] TPM cleanup Jason Gunthorpe
2013-09-23 18:14 ` [PATCH 01/13] tpm: ibmvtpm: Use %zd formatting for size_t format arguments Jason Gunthorpe
2013-10-01 21:58 ` Peter Hüwe
2013-10-02 19:37 ` [tpmdd-devel] " Ashley D Lai
2013-09-23 18:14 ` [PATCH 02/13] tpm atmel: Call request_region with the correct base Jason Gunthorpe
[not found] ` <201310020000.13490.PeterHuewe@gmx.de>
2013-10-03 0:11 ` [tpmdd-devel] " Ashley D Lai
2013-10-03 4:36 ` Jason Gunthorpe
2013-10-04 17:21 ` Joel Schopp
2013-09-23 18:14 ` [PATCH 03/13] tpm: xen-tpmfront: Fix default durations Jason Gunthorpe
2013-09-23 18:51 ` Konrad Rzeszutek Wilk
2013-09-23 18:57 ` Daniel De Graaf
2013-09-23 18:14 ` [PATCH 04/13] tpm: Store devname in the tpm_chip Jason Gunthorpe
2013-10-04 15:57 ` [tpmdd-devel] " Ashley Lai
2013-09-23 18:14 ` [PATCH 05/13] tpm: Use container_of to locate the tpm_chip in tpm_open Jason Gunthorpe
2013-10-05 1:47 ` [tpmdd-devel] " Ashley Lai
2013-09-23 18:14 ` [PATCH 06/13] tpm: Remove redundant dev_set_drvdata Jason Gunthorpe
2013-10-05 2:14 ` [tpmdd-devel] " Ashley Lai
2013-09-23 18:14 ` [PATCH 07/13] tpm: Remove tpm_show_caps_1_2 Jason Gunthorpe
[not found] ` <201310020009.22952.PeterHuewe@gmx.de>
2013-10-01 22:21 ` Jason Gunthorpe
2013-10-01 22:38 ` [tpmdd-devel] " Peter Hüwe
2013-09-23 18:14 ` [PATCH 08/13] tpm: Pull everything related to /dev/tpmX into tpm-dev.c Jason Gunthorpe
2013-10-01 22:52 ` Peter Hüwe
2013-10-01 22:57 ` Jason Gunthorpe
2013-10-01 23:14 ` Peter Hüwe
2013-10-01 23:23 ` Jason Gunthorpe
2013-10-03 5:05 ` Jason Gunthorpe
2013-10-04 15:50 ` TPM.ko module rename (was tpm: Pull everything related to /dev/tpmX into tpm-dev.c) Peter Hüwe
2013-10-04 16:28 ` Jason Gunthorpe
2013-10-04 16:45 ` Ashley Lai
2013-09-23 18:14 ` [PATCH 09/13] tpm: Pull everything related to sysfs into tpm-sysfs.c Jason Gunthorpe
2013-09-23 18:54 ` [tpmdd-devel] " Daniel De Graaf
2013-09-23 19:36 ` Jason Gunthorpe
2013-09-23 20:20 ` Daniel De Graaf
2013-09-23 20:42 ` Jason Gunthorpe
2013-09-23 22:00 ` Daniel De Graaf
2013-09-23 22:23 ` Jason Gunthorpe [this message]
2013-09-24 14:28 ` Daniel De Graaf
2013-09-30 18:10 ` Jason Gunthorpe
2013-09-30 20:36 ` Daniel De Graaf
2013-09-30 21:20 ` Jason Gunthorpe
2013-09-30 22:09 ` Joel Schopp
2013-10-04 17:08 ` Jason Gunthorpe
2013-10-04 19:17 ` Stefan Berger
2013-10-04 22:02 ` Peter Hüwe
2013-10-07 15:06 ` Daniel De Graaf
2013-10-08 9:15 ` AW: [TrouSerS-tech] " Fuchs, Andreas
2013-10-09 17:38 ` Jason Gunthorpe
2013-10-10 7:42 ` AW: " Fuchs, Andreas
2013-10-10 16:50 ` Jason Gunthorpe
2013-09-23 18:14 ` [PATCH 10/13] tpm: Create a tpm_class_ops structure and use it in the drivers Jason Gunthorpe
2013-09-23 18:14 ` [PATCH 11/13] tpm: Use the ops structure instead of a copy in tpm_vendor_specific Jason Gunthorpe
2013-09-23 18:14 ` [PATCH 12/13] tpm: st33: Remove chip->data_buffer access from this driver Jason Gunthorpe
2013-09-23 18:14 ` [PATCH 13/13] tpm: Make tpm-dev allocate a per-file structure Jason Gunthorpe
2013-09-23 21:27 ` [tpmdd-devel] [PATCH 00/13] TPM cleanup Joel Schopp
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