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Message-ID: <3d937327f3c91351c3c3cd4877c121b9b1405868.camel@linux.ibm.com>
Subject: Re: [RFC][PATCH 4/8] ima: Add digest_cache_measure and
 digest_cache_appraise boot-time policies
From: Mimi Zohar <zohar@linux.ibm.com>
To: Roberto Sassu <roberto.sassu@huaweicloud.com>, corbet@lwn.net,
        dmitry.kasatkin@gmail.com, eric.snowberg@oracle.com,
        paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com
Cc: linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
        linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org,
        wufan@linux.microsoft.com, pbrobinson@gmail.com, zbyszek@in.waw.pl,
        hch@lst.de, mjg59@srcf.ucam.org, pmatilai@redhat.com, jannh@google.com,
        dhowells@redhat.com, jikos@kernel.org, mkoutny@suse.com,
        ppavlu@suse.com, petr.vorel@gmail.com, petrtesarik@huaweicloud.com,
        mzerqung@0pointer.de, kgold@linux.ibm.com,
        Roberto Sassu <roberto.sassu@huawei.com>
Date: Mon, 11 Mar 2024 09:01:03 -0400
In-Reply-To: <20240214143525.2205481-5-roberto.sassu@huaweicloud.com>
References: <20240214143525.2205481-1-roberto.sassu@huaweicloud.com>
	 <20240214143525.2205481-5-roberto.sassu@huaweicloud.com>
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On Wed, 2024-02-14 at 15:35 +0100, Roberto Sassu wrote:
> From: Roberto Sassu <roberto.sassu@huawei.com>
> 
> Specify the 'digest_cache_measure' boot-time policy with 'ima_policy=' in
> the kernel command line to add the following rule at the beginning of the
> IMA policy, before other rules:
> 
> measure func=DIGEST_LIST_CHECK pcr=12
> 
> which will measure digest lists into PCR 12 (or the value in
> CONFIG_IMA_DIGEST_CACHE_MEASURE_PCR_IDX).
> 
> 'digest_cache_measure' also adds 'digest_cache=content pcr=12' to the other
> measure rules, if they have a compatible IMA hook. The PCR value still
> comes from CONFIG_IMA_DIGEST_CACHE_MEASURE_PCR_IDX.
> 
> Specify 'digest_cache_appraise' to add the following rule at the beginning,
> before other rules:
> 
> appraise func=DIGEST_LIST_CHECK appraise_type=imasig|modsig
> 
> which will appraise digest lists with IMA signatures or module-style
> appended signatures.
> 
> 'digest_cache_appraise' also adds 'digest_cache=content' to the other
> appraise rules, if they have a compatible IMA hook.

Defining two new built-in policies - digest_cache_measure, digest_cache_appraise
- in a single patch would be acceptable, if there wasn't anything else going on.

Changing other policy rules should not be made in this patch.  A clear
explanation as to why other policy rules need to be modified is needed.  It
shouldn't be hidden here.

thanks,

Mimi

> 
> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
>