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From:   David Howells <dhowells@redhat.com>
In-Reply-To: <8b9477e150d7c939dc0def3ebb4443efcc83cd85.camel@pengutronix.de>
References: <8b9477e150d7c939dc0def3ebb4443efcc83cd85.camel@pengutronix.de> <74830d4f-5a76-8ba8-aad0-0d79f7c01af9@pengutronix.de> <6dc99fd9ffbc5f405c5f64d0802d1399fc6428e4.camel@kernel.org> <d1bed49f89495ceb529355cb41655a208fdb2197.camel@linux.ibm.com>
To:     Jan =?us-ascii?Q?=3D=3FISO-8859-1=3FQ=3FL=3DFCbbe=3F=3D?= 
        <jlu@pengutronix.de>
Cc:     dhowells@redhat.com, Mimi Zohar <zohar@linux.ibm.com>,
        Jarkko Sakkinen <jarkko@kernel.org>,
        Ahmad Fatoum <a.fatoum@pengutronix.de>,
        James Bottomley <jejb@linux.ibm.com>, keyrings@vger.kernel.org,
        Sumit Garg <sumit.garg@linaro.org>,
        linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-security-module@vger.kernel.org, kernel@pengutronix.de
Subject: Re: Migration to trusted keys: sealing user-provided key?
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Date:   Mon, 01 Feb 2021 11:36:01 +0000
Message-ID: <4153718.1612179361@warthog.procyon.org.uk>
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Jan L=C3=BCbbe <jlu@pengutronix.de> wrote:

> ... But at this point, you can still do 'keyctl read' on that key, exposi=
ng
> the key material to user space.

I wonder if it would help to provide a keyctl function to mark a key as bei=
ng
permanently unreadable - so that it overrides the READ permission bit.

Alternatively, you can disable READ and SETATTR permission - but that then
prevents you from removing other perms if you want to :-/

David