From: Stefan Berger <stefanb@linux.vnet.ibm.com>
To: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Cc: Joel Schopp <jschopp@linux.vnet.ibm.com>,
Leonidas Da Silva Barbosa <leosilva@linux.vnet.ibm.com>,
linux-kernel@vger.kernel.org, Rajiv Andrade <mail@srajiv.net>,
tpmdd-devel@lists.sourceforge.net,
Richard Maciel Costa <richardm@br.ibm.com>,
"trousers-tech@lists.sourceforge.net"
<trousers-tech@lists.sourceforge.net>,
Sirrix AG <tpmdd@sirrix.com>
Subject: Re: [tpmdd-devel] [PATCH 09/13] tpm: Pull everything related to sysfs into tpm-sysfs.c
Date: Fri, 04 Oct 2013 15:17:36 -0400 [thread overview]
Message-ID: <524F1450.6060406@linux.vnet.ibm.com> (raw)
In-Reply-To: <20131004170803.GB6955@obsidianresearch.com>
On 10/04/2013 01:08 PM, Jason Gunthorpe wrote:
> On Mon, Sep 30, 2013 at 05:09:51PM -0500, Joel Schopp wrote:
>
>>> So far, nobody I have talked to has offered any strong opinions on
>>> what locality should be used or how it should be set. I think finding
>>> a developer of trousers may be the most useful to talk about how the
>>> ioctl portion of this would need to be set up - if someone is actually
>>> needed.
>> I am a TrouSerS developer and am ccing Richard, another TrouSerS
>> developer, and ccing the trousers-tech list. It would be good if you
>> could elaborate on the question and context for those not following the
>> entire thread, myself included.
> Two questions:
>
> Is userspace interested in using the TPM Locality feature, and if so
> is there any thoughts on what the interface should be?
In terms of interface it should probably be an ioctl so that whoever
holds the fd to /dev/tpm0 gets to choose the locality.
Locality allows the resetting of certain PCRs. See section 3.7 in
http://www.trustedcomputinggroup.org/files/static_page_files/8E45D739-1A4B-B294-D06274E7047730FD/TCG_PCClientTPMInterfaceSpecification_TIS__1-3_27_03212013.pdf
Locality 4 can only be used by the hardware (section 2.2).
Locality has an influence on the following TPM commands:
TSC_ResetEstablishmentBit, Seal, Sealx, CreateWrapKey, UnSeal,
GetPubKey, CMK_CreateKey, SHA1CompleteExtend, CertifyKey, Extend,
PCR_Reset, NV_ReadValue, NV_WriteValue, and others. Some of the
commands allow operations to succeed if a previously selected locality
is also currently the chosen one. (If you have control over choosing the
locality, at least that part won't prevent you from succeeding..)
http://www.trustedcomputinggroup.org/files/static_page_files/72C33D71-1A4B-B294-D02C7DF86630BE7C/TPM%20Main-Part%203%20Commands_v1.2_rev116_01032011.pdf
The worst would probably be if an application was to reset a PCR while
another one is using that PCR or just for malicious purposes. Not
providing support for choosing locality would mean that applications
could still use PCRs 16 and 23 for their own purposes and can compete
for their exclusive usage while being able to reset only those two.
Are there use case for resetting PCRs from user space? If not I'd not
support choice for locality from user space.
Stefan
>
> Is the kernel interested in using the TPM Locality feature? What for?
>
> Jason
>
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next prev parent reply other threads:[~2013-10-04 19:17 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
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 [this message]
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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