From: Mimi Zohar <zohar@linux.ibm.com>
To: Roberto Sassu <roberto.sassu@huawei.com>,
jarkko.sakkinen@linux.intel.com
Cc: linux-integrity@vger.kernel.org,
linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2, RESEND 0/3] tpm: retrieve digest size of unknown algorithms from TPM
Date: Wed, 26 Sep 2018 10:40:40 -0400 [thread overview]
Message-ID: <1537972840.3459.6.camel@linux.ibm.com> (raw)
In-Reply-To: <20180917093820.20500-1-roberto.sassu@huawei.com>
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>
Thanks!
Mimi
next prev parent reply other threads:[~2018-09-26 14:41 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 ` Mimi Zohar [this message]
2018-09-26 18:03 ` [PATCH v2, RESEND 0/3] tpm: retrieve digest size of unknown algorithms from TPM Mimi Zohar
2018-09-27 6:50 ` Roberto Sassu
2018-09-27 13:43 ` Mimi Zohar
2018-09-27 13:50 ` Jarkko Sakkinen
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