From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: linux-integrity@vger.kernel.org,
linux-security-module@vger.kernel.org,
Peter Huewe <PeterHuewe@gmx.de>, Jason Gunthorpe <jgg@ziepe.ca>,
Tomas Winkler <tomas.winkler@intel.com>,
Tadeusz Struk <tadeusz.struk@intel.com>,
Stefan Berger <stefanb@linux.vnet.ibm.com>,
Nayna Jain <nayna@linux.ibm.com>,
stable@vger.kernel.org
Subject: Re: [PATCH v10 08/17] tpm: call tpm2_flush_space() on error in tpm_try_transmit()
Date: Tue, 29 Jan 2019 23:11:17 +0200 [thread overview]
Message-ID: <20190129211117.GA18819@linux.intel.com> (raw)
In-Reply-To: <1548788539.2888.40.camel@HansenPartnership.com>
On Tue, Jan 29, 2019 at 11:02:19AM -0800, James Bottomley wrote:
> On Tue, 2019-01-29 at 20:53 +0200, Jarkko Sakkinen wrote:
> > On Tue, Jan 29, 2019 at 09:06:01AM -0800, James Bottomley wrote:
> > > On Wed, 2019-01-16 at 23:23 +0200, Jarkko Sakkinen wrote:
> > > [...]
> > > > - rc = tpm2_commit_space(chip, space, ordinal, buf, &len);
> > > > +out_space:
> > > > + if (rc)
> > > > + tpm2_flush_space(chip);
> > > > + else
> > > > + rc = tpm2_commit_space(chip, space, ordinal,
> > > > buf,
> > > > &len);
> > >
> > > I don't think this is quite right. tpm2_flush_space only flushes
> > > the handles it knows about and those are the ones from before the
> > > TPM operation was attempted. If the operation has altered the
> > > internal state we could miss a created handle in this flush and it
> > > would effectively reside forever in the TPM. We should be able to
> > > rely on the TPM preserving the original state if it returns an
> > > error, so I think your patch works for that part. However rc is
> > > also set to -EFAULT on a transmission error and if that's on the
> > > receive path, the TPM may have changed state before the error
> > > occurred.
> >
> > If TPM is working properly in the first place, tpm2_commit_space() is
> > always called (e.g. in a situation where TPM gives a TPM error). Your
> > deduction about the opposite is absolutely correct. Thanks!
> >
> > > If the object is to move the TPM back to where it was before the
> > > error occurred, even in the case of transmit errors, then I think
> > > we need to invent a new kind of flush that queries the current TPM
> > > state and then flushes everything.
> >
> > I think this consideration is anyway out of scope for this patch set.
>
> I certainly agree the problem existed before and this makes it no
> worse.
>
> > I'd hope you would also skim through v11 as soon as I get it
> > prepared, at least the patches where I've added an explicit CC (one
> > or two at most).
>
> Sure, as you can see, I'm up to 8. I'll complete the review and then
> set up an environment to test.
Great, thank you! I won't try to land this to v5.1 so there is no any
kind of rush, because there is a show stopper that I need sort out with
v5.0, as you've seen...
/Jarkko
next prev parent reply other threads:[~2019-01-29 21:11 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-16 21:23 [PATCH v10 00/17] Remove nested TPM operations Jarkko Sakkinen
2019-01-16 21:23 ` [PATCH v10 01/17] tpm: use tpm_buf in tpm_transmit_cmd() as the IO parameter Jarkko Sakkinen
2019-01-16 21:23 ` [PATCH v10 02/17] tpm: fix invalid return value in pubek_show() Jarkko Sakkinen
2019-01-16 21:23 ` [PATCH v10 03/17] tpm: return 0 from pcrs_show() when tpm1_pcr_read() fails Jarkko Sakkinen
2019-01-16 21:23 ` [PATCH v10 04/17] tpm: print tpm2_commit_space() error inside tpm2_commit_space() Jarkko Sakkinen
2019-01-16 21:23 ` [PATCH v10 05/17] tpm: declare struct tpm_header Jarkko Sakkinen
2019-01-16 21:23 ` [PATCH v10 06/17] tpm: access command header through struct in tpm_try_transmit() Jarkko Sakkinen
2019-01-16 21:23 ` [PATCH v10 07/17] tpm: encapsulate tpm_dev_transmit() Jarkko Sakkinen
2019-01-16 21:23 ` [PATCH v10 08/17] tpm: call tpm2_flush_space() on error in tpm_try_transmit() Jarkko Sakkinen
2019-01-29 17:06 ` James Bottomley
2019-01-29 18:53 ` Jarkko Sakkinen
2019-01-29 19:02 ` James Bottomley
2019-01-29 21:11 ` Jarkko Sakkinen [this message]
2019-01-16 21:23 ` [PATCH v10 09/17] tpm: clean up tpm_try_transmit() error handling flow Jarkko Sakkinen
2019-01-16 21:23 ` [PATCH v10 10/17] tpm: move tpm_validate_commmand() to tpm2-space.c Jarkko Sakkinen
2019-01-16 21:23 ` [PATCH v10 11/17] tpm: move TPM space code out of tpm_transmit() Jarkko Sakkinen
2019-01-16 21:23 ` [PATCH v10 12/17] tpm: remove @space from tpm_transmit() Jarkko Sakkinen
2019-01-16 21:23 ` [PATCH v10 13/17] tpm: use tpm_try_get_ops() in tpm-sysfs.c Jarkko Sakkinen
2019-01-16 21:23 ` [PATCH v10 14/17] tpm: remove TPM_TRANSMIT_UNLOCKED flag Jarkko Sakkinen
2019-01-16 21:23 ` [PATCH v10 15/17] tpm: introduce tpm_chip_start() and tpm_chip_stop() Jarkko Sakkinen
2019-01-16 21:23 ` [PATCH v10 16/17] tpm: take TPM chip power gating out of tpm_transmit() Jarkko Sakkinen
2019-01-16 21:23 ` [PATCH v10 17/17] tpm: remove @flags from tpm_transmit() Jarkko Sakkinen
2019-01-23 18:20 ` [PATCH v10 00/17] Remove nested TPM operations Jarkko Sakkinen
2019-01-23 18:53 ` Stefan Berger
2019-01-23 18:59 ` Winkler, Tomas
2019-01-29 12:33 ` Jarkko Sakkinen
2019-01-29 14:16 ` Winkler, Tomas
2019-01-29 18:30 ` Jarkko Sakkinen
2019-01-29 12:31 ` Jarkko Sakkinen
2019-01-31 0:28 ` James Bottomley
2019-01-31 16:11 ` Jarkko Sakkinen
2019-01-25 1:05 ` Jerry Snitselaar
2019-01-29 12:33 ` Jarkko Sakkinen
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