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Subject: Re: [PATCH v1 5/6] KEYS: measure queued keys
From:   Mimi Zohar <zohar@linux.ibm.com>
To:     Lakshmi Ramasubramanian <nramas@linux.microsoft.com>,
        dhowells@redhat.com, casey@schaufler-ca.com, sashal@kernel.org,
        jamorris@linux.microsoft.com,
        linux-security-module@vger.kernel.org,
        linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org,
        keyrings@vger.kernel.org
Date:   Wed, 23 Oct 2019 14:49:25 -0400
In-Reply-To: <1571853139.5104.154.camel@linux.ibm.com>
References: <20191023001818.3684-1-nramas@linux.microsoft.com>
         <20191023001818.3684-6-nramas@linux.microsoft.com>
         <1571836990.5104.96.camel@linux.ibm.com>
         <89d778d1-1ac9-4a58-b159-7db68b7fa4ad@linux.microsoft.com>
         <1571853139.5104.154.camel@linux.ibm.com>
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On Wed, 2019-10-23 at 13:52 -0400, Mimi Zohar wrote:
> On Wed, 2019-10-23 at 10:34 -0700, Lakshmi Ramasubramanian wrote:
> > On 10/23/19 6:23 AM, Mimi Zohar wrote:
> > 
> > > The ordering of this patch set is awkward.  It should first introduce
> > > a generic method for measuring keys based on the keyring.  Then add
> > > the additional support needed for the specific builtin_trusted_keys
> > > keyring usecase.
> > 
> > Would the following ordering of the patch set be acceptable:
> > 
> >   => PATCH 0/5: Cover letter
> > 
> >   => PATCH 1/5: Define the enum "hook(BUILTIN_TRUSTED_KEYS)" in ima.h
> > 
> >   => PATCH 2/5: Define ima hook
> >                 This will initially do nothing if ima is not yet
> >                 initialized.
> >                 Call process_buffer_measurement() if ima is initialized.
> > 
> >   => PATCH 3/5: key_create_or_update change and the call to ima hook
> > 
> >   => PATCH 4/5: Queue\De-Queue of key measurement requests.
> >                 Enable queuing of key in the ima hook if ima is not
> >                 initialized.
> > 
> >   => PATCH 5/5: ima policy to enable measurement of keys which will
> >                 enable end-to-end working of this feature.
> 
> The first patches need to introduce the generic concept of measuring
> keys based on policy.  Only afterwards would you add any builtin
> trusted keyring specific code.

1. Extend the IMA policy language to support identifying keyrings
2. Define a new IMA hook which calls process_buffer_measurement()
3. Call the new IMA hook (eg. from post_key_create_or_update)
4. Define an early workqueue for saving keys loaded prior to IMA is
initialized.  (Remember we don't hard code policy in the kernel.)

I'll be pushing out linux-integrity shortly.  For the time being,
please base your patches on -rc3.

thanks,

Mimi