Linux-Integrity Archive on lore.kernel.org
 help / color / Atom feed
From: Mimi Zohar <zohar@linux.ibm.com>
To: Roberto Sassu <roberto.sassu@huawei.com>,
	"James.Bottomley@HansenPartnership.com" 
	<James.Bottomley@HansenPartnership.com>,
	"jarkko.sakkinen@linux.intel.com"
	<jarkko.sakkinen@linux.intel.com>,
	Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
Cc: "linux-integrity@vger.kernel.org"
	<linux-integrity@vger.kernel.org>,
	"linux-security-module@vger.kernel.org" 
	<linux-security-module@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Silviu Vlasceanu <Silviu.Vlasceanu@huawei.com>,
	"stable@vger.kernel.org" <stable@vger.kernel.org>
Subject: Re: [PATCH v3 2/8] ima: Switch to ima_hash_algo for boot aggregate
Date: Mon, 02 Mar 2020 09:46:34 -0500
Message-ID: <1583160394.8544.89.camel@linux.ibm.com> (raw)
In-Reply-To: <8a6fb34e18b147fa811e82c78fb30d66@huawei.com>


> > > > On Mon, 2020-02-10 at 11:00 +0100, Roberto Sassu wrote: 
> > My initial patch attempted to use any common TPM and kernel hash
> > algorithm to calculate the boot_aggregate.  The discussion with James
> > was pretty clear, which you even stated in the Changelog.  Either we
> > use the IMA default hash algorithm, SHA256 for TPM 2.0 or SHA1 for TPM
> > 1.2 for the boot-aggregate.
> 
> Ok, I didn't understand fully. I thought we should use the default IMA
> algorithm and select SHA256 as fallback choice for TPM 2.0 if there is no
> PCR bank for default algorithm.

Yes, preference is given to the IMA default algorithm, but it should
fall back to using SHA256 or SHA1, based on the TPM.

> I additionally implemented the logic to
> select the first PCR bank if the SHA256 PCR bank is not available but I can
> remove it.
> 
> SHA256 should be the minimum requirement for boot aggregate. The
> advantage of using the default IMA algorithm is that it will be possible to
> select stronger algorithms when they are supported by the TPM. We might
> introduce a new option to specify only the algorithm for boot aggregate,
> like James suggested to support embedded systems. Let me know which
> option you prefer.

I don't remember James saying that, but if the community really wants
that support, then it should be upstreamed independently, as a
separate patch.  Let's first get the basics working.

thanks,

Mimi


  reply index

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-10 10:00 [PATCH v3 0/8] ima: support stronger algorithms for attestation Roberto Sassu
2020-02-10 10:00 ` [PATCH v3 1/8] tpm: Initialize crypto_id of allocated_banks to HASH_ALGO__LAST Roberto Sassu
2020-02-10 16:00   ` Jarkko Sakkinen
2020-02-10 10:00 ` [PATCH v3 2/8] ima: Switch to ima_hash_algo for boot aggregate Roberto Sassu
2020-02-10 22:23   ` Mimi Zohar
2020-02-11 10:09     ` Roberto Sassu
2020-03-02 13:41       ` Mimi Zohar
2020-03-02 14:28         ` Roberto Sassu
2020-03-02 14:46           ` Mimi Zohar [this message]
2020-03-02 15:11             ` Roberto Sassu
2020-03-02 17:33               ` Mimi Zohar
2020-02-10 10:00 ` [PATCH v3 3/8] ima: Evaluate error in init_ima() Roberto Sassu
2020-02-10 10:00 ` [PATCH v3 4/8] ima: Store template digest directly in ima_template_entry Roberto Sassu

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=1583160394.8544.89.camel@linux.ibm.com \
    --to=zohar@linux.ibm.com \
    --cc=James.Bottomley@HansenPartnership.com \
    --cc=Silviu.Vlasceanu@huawei.com \
    --cc=dmitry.kasatkin@gmail.com \
    --cc=jarkko.sakkinen@linux.intel.com \
    --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=stable@vger.kernel.org \
    /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

Linux-Integrity Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-integrity/0 linux-integrity/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-integrity linux-integrity/ https://lore.kernel.org/linux-integrity \
		linux-integrity@vger.kernel.org
	public-inbox-index linux-integrity

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-integrity


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git