From: jarkko.sakkinen@linux.intel.com (Jarkko Sakkinen)
To: linux-security-module@vger.kernel.org
Subject: [PATCH v2, RESEND 0/3] tpm: retrieve digest size of unknown algorithms from TPM
Date: Thu, 27 Sep 2018 16:50:59 +0300 [thread overview]
Message-ID: <20180927135059.GD8242@linux.intel.com> (raw)
In-Reply-To: <8bbff5b1-f4ba-4e38-57fc-05d9ddabea5c@huawei.com>
On Thu, Sep 27, 2018 at 08:50:14AM +0200, Roberto Sassu wrote:
> On 9/26/2018 8:03 PM, Mimi Zohar wrote:
> > On Wed, 2018-09-26 at 10:40 -0400, Mimi Zohar wrote:
> > > On Mon, 2018-09-17 at 11:38 +0200, Roberto Sassu wrote:
> > > > Resending to maintainer with correct mailing lists in CC.
> > > >
> > > > The TPM driver currently relies on the crypto subsystem to determine the
> > > > digest size of supported TPM algorithms. In the future, TPM vendors might
> > > > implement new algorithms in their chips, and those algorithms might not
> > > > be supported by the crypto subsystem.
> > > >
> > > > Usually, vendors provide patches for the new hardware, and likely
> > > > the crypto subsystem will be updated before the new algorithm is
> > > > introduced. However, old kernels might be updated later, after patches
> > > > are included in the mainline kernel. This would leave the opportunity
> > > > for attackers to misuse PCRs, as PCR banks with an unknown algorithm
> > > > are not extended.
> > > >
> > > > This patch set provides a long term solution for this issue. If a TPM
> > > > algorithm is not known by the crypto subsystem, the TPM driver retrieves
> > > > the digest size from the TPM with a PCR read. All the PCR banks are
> > > > extended, even if the algorithm is not yet supported by the crypto
> > > > subsystem.
> > >
> > > Other than checking the digest size before copying the pcrread buffer,
> > > the patches look good. ?Please add my Ack on all 3 patches.
> > >
> > > (New address) Acked-by: Mimi Zohar <zohar@linux.ibm.com>
> >
> > I've reviewed, and am currently running with these patches.
> >
> > Even if the IMA changes were in a separate patch, we wouldn't be able
> > to break up the patch set anyway. ?Jarkko, I'd appreciate your
> > carrying the entire patch set.
> >
> > Roberto, a similar change needs to be made for tpm_pcr_extend. ?Are
> > you planning on posting those changes as well?
>
> Yes, I was planning to send the patch after this patch set is accepted.
>
> Roberto
Mimi, I can carry it yes.
/Jarkko
prev parent reply other threads:[~2018-09-27 13:50 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-17 9:38 [PATCH v2, RESEND 0/3] tpm: retrieve digest size of unknown algorithms from TPM Roberto Sassu
2018-09-17 9:38 ` [PATCH v2, RESEND 1/3] tpm: rename and export tpm2_digest and tpm2_algorithms Roberto Sassu
2018-09-17 9:38 ` [PATCH v2, RESEND 2/3] tpm: modify tpm_pcr_read() definition to pass TPM hash algorithms Roberto Sassu
2018-09-21 10:24 ` Roberto Sassu
2018-09-21 13:59 ` Mimi Zohar
2018-09-21 21:57 ` Jarkko Sakkinen
2018-09-25 13:27 ` Jarkko Sakkinen
2018-09-17 9:38 ` [PATCH v2, RESEND 3/3] tpm: retrieve digest size of unknown algorithms with PCR read Roberto Sassu
2018-09-25 14:00 ` Jarkko Sakkinen
2018-09-26 14:40 ` [PATCH v2, RESEND 0/3] tpm: retrieve digest size of unknown algorithms from TPM Mimi Zohar
2018-09-26 18:03 ` Mimi Zohar
2018-09-27 6:50 ` Roberto Sassu
2018-09-27 13:43 ` Mimi Zohar
2018-09-27 13:50 ` Jarkko Sakkinen [this message]
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