Received-SPF: pass (google.com: domain of linux-kernel+bounces-97163-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) client-ip=147.75.80.249;
Message-ID: <f1228f212520c66a5f3610627a7e26f736b384c5.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: Fri, 08 Mar 2024 09:23:13 -0500
In-Reply-To: <e10207bd82ee13fb088f9efc12e10a5478b6926d.camel@huaweicloud.com>
References: <20240214143525.2205481-1-roberto.sassu@huaweicloud.com>
	 <20240214143525.2205481-5-roberto.sassu@huaweicloud.com>
	 <ed5df367582f0c5e212638a12204fd20fd8e46e5.camel@linux.ibm.com>
	 <e10207bd82ee13fb088f9efc12e10a5478b6926d.camel@huaweicloud.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit


> > > @@ -971,6 +1006,16 @@ void __init ima_init_policy(void)
> > >  {
> > >  	int build_appraise_entries, arch_entries;
> > >  
> > > +	/*
> > > +	 * We need to load digest cache rules at the beginning, to avoid dont_
> > > +	 * rules causing ours to not be reached.
> > > +	 */
> > 
> > "lockdown" trusts IMA to measure and appraise kernel modules, if the rule
> > exists.  Placing the digest_cache first breaks this trust.
> 
> The new rules don't prevent other rules to be reached, since they are
> 'do' and not 'don_t' rules.

My mistake.  These are just the rules for measuring or appraising the digest
cache lists themselves, not the actual policy rules for using the digest_cache. 
This should be fine.

Perhaps update the comment to reflect initramfs usage.


thanks,

Mimi