From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Roberto Sassu <roberto.sassu@huawei.com>
Cc: tpmdd-devel@lists.sourceforge.net,
linux-ima-devel@lists.sourceforge.net,
linux-integrity@vger.kernel.org,
linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/3] tpm: retrieve digest size of unknown algorithms from TPM
Date: Wed, 4 Oct 2017 10:32:58 +0300 [thread overview]
Message-ID: <20171004073258.be2j7mdeud2pjbyk@linux.intel.com> (raw)
In-Reply-To: <20170925111950.21511-1-roberto.sassu@huawei.com>
Hi
And apologies for late review.
On Mon, Sep 25, 2017 at 01:19:47PM +0200, Roberto Sassu wrote:
> This patch set derives from a larger patch set which modifies the TPM
> driver API in order to extend a PCR with multiple digests. It can be
> retrieved at the URL:
>
> https://sourceforge.net/p/tpmdd/mailman/message/35905412/
A patch set should be able to live on its own. Please remove this link.
I don't care about that patch set at this point and I'm not going to
give any distant promises.
> 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.
This part makes sense to me.
/Jarkko
WARNING: multiple messages have this Message-ID (diff)
From: jarkko.sakkinen@linux.intel.com (Jarkko Sakkinen)
To: linux-security-module@vger.kernel.org
Subject: [PATCH 0/3] tpm: retrieve digest size of unknown algorithms from TPM
Date: Wed, 4 Oct 2017 10:32:58 +0300 [thread overview]
Message-ID: <20171004073258.be2j7mdeud2pjbyk@linux.intel.com> (raw)
In-Reply-To: <20170925111950.21511-1-roberto.sassu@huawei.com>
Hi
And apologies for late review.
On Mon, Sep 25, 2017 at 01:19:47PM +0200, Roberto Sassu wrote:
> This patch set derives from a larger patch set which modifies the TPM
> driver API in order to extend a PCR with multiple digests. It can be
> retrieved at the URL:
>
> https://sourceforge.net/p/tpmdd/mailman/message/35905412/
A patch set should be able to live on its own. Please remove this link.
I don't care about that patch set at this point and I'm not going to
give any distant promises.
> 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.
This part makes sense to me.
/Jarkko
--
To unsubscribe from this list: send the line "unsubscribe linux-security-module" in
the body of a message to majordomo at vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
next prev parent reply other threads:[~2017-10-04 7:33 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-25 11:19 [PATCH 0/3] tpm: retrieve digest size of unknown algorithms from TPM Roberto Sassu
2017-09-25 11:19 ` Roberto Sassu
2017-09-25 11:19 ` Roberto Sassu
2017-09-25 11:19 ` [PATCH 1/3] tpm: move PCR read code to static function tpm2_pcr_read_common() Roberto Sassu
2017-09-25 11:19 ` Roberto Sassu
2017-09-25 11:19 ` Roberto Sassu
2017-10-04 10:45 ` Jarkko Sakkinen
2017-10-04 10:45 ` Jarkko Sakkinen
2017-09-25 11:19 ` [PATCH 2/3] tpm: retrieve digest size of unknown algorithms with PCR read Roberto Sassu
2017-09-25 11:19 ` Roberto Sassu
2017-09-25 11:19 ` Roberto Sassu
2017-10-04 11:12 ` Jarkko Sakkinen
2017-10-04 11:12 ` Jarkko Sakkinen
2017-09-25 11:19 ` [PATCH 3/3] tpm: add the crypto algorithm identifier to active_bank_info Roberto Sassu
2017-09-25 11:19 ` Roberto Sassu
2017-09-25 11:19 ` Roberto Sassu
2017-10-04 11:22 ` Jarkko Sakkinen
2017-10-04 11:22 ` Jarkko Sakkinen
2017-10-04 7:32 ` Jarkko Sakkinen [this message]
2017-10-04 7:32 ` [PATCH 0/3] tpm: retrieve digest size of unknown algorithms from TPM Jarkko Sakkinen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20171004073258.be2j7mdeud2pjbyk@linux.intel.com \
--to=jarkko.sakkinen@linux.intel.com \
--cc=linux-ima-devel@lists.sourceforge.net \
--cc=linux-integrity@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-security-module@vger.kernel.org \
--cc=roberto.sassu@huawei.com \
--cc=tpmdd-devel@lists.sourceforge.net \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.