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Subject: Re: [PATCH v4 2/6] IMA: conditionally allow empty rule data
From:   Mimi Zohar <zohar@linux.ibm.com>
To:     Tushar Sugandhi <tusharsu@linux.microsoft.com>,
        stephen.smalley.work@gmail.com, casey@schaufler-ca.com,
        agk@redhat.com, snitzer@redhat.com, gmazyland@gmail.com
Cc:     tyhicks@linux.microsoft.com, sashal@kernel.org, jmorris@namei.org,
        nramas@linux.microsoft.com, linux-integrity@vger.kernel.org,
        selinux@vger.kernel.org, linux-security-module@vger.kernel.org,
        linux-kernel@vger.kernel.org, dm-devel@redhat.com
Date:   Thu, 22 Oct 2020 16:38:58 -0400
In-Reply-To: <20200923192011.5293-3-tusharsu@linux.microsoft.com>
References: <20200923192011.5293-1-tusharsu@linux.microsoft.com>
         <20200923192011.5293-3-tusharsu@linux.microsoft.com>
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Hi Tushar,

On Wed, 2020-09-23 at 12:20 -0700, Tushar Sugandhi wrote:
> ima_match_rule_data() permits the func to pass empty func_data.
> For instance, for the following func, the func_data keyrings= is
> optional.
>     measure func=KEY_CHECK keyrings=.ima
> 
> But a new func in future may want to constrain the func_data to
> be non-empty.  ima_match_rule_data() should support this constraint
> and it shouldn't be hard-coded in ima_match_rule_data().
> 
> Update ima_match_rule_data() to conditionally allow empty func_data
> for the func that needs it.
> 
> Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com>

Policy rules may constrain what is measured, but that decision should
be left to the system owner or admin.

Mimi