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Date:   Wed, 20 Jan 2021 06:16:23 +0200
From:   Jarkko Sakkinen <jarkko@kernel.org>
To:     =?iso-8859-1?Q?Micka=EBl_Sala=FCn?= <mic@digikod.net>
Cc:     David Howells <dhowells@redhat.com>,
        David Woodhouse <dwmw2@infradead.org>,
        "David S . Miller" <davem@davemloft.net>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        James Morris <jmorris@namei.org>,
        =?iso-8859-1?Q?Micka=EBl_Sala=FCn?= <mic@linux.microsoft.com>,
        Mimi Zohar <zohar@linux.ibm.com>,
        "Serge E . Hallyn" <serge@hallyn.com>, keyrings@vger.kernel.org,
        linux-crypto@vger.kernel.org, linux-integrity@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org
Subject: Re: [PATCH v3 06/10] certs: Make blacklist_vet_description() more
 strict
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References: <20210114151909.2344974-1-mic@digikod.net>
 <20210114151909.2344974-7-mic@digikod.net>
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On Thu, Jan 14, 2021 at 04:19:05PM +0100, Micka?l Sala?n wrote:
> From: Micka?l Sala?n <mic@linux.microsoft.com>
> 
> Before exposing this new key type to user space, make sure that only
> meaningful blacklisted hashes are accepted.  This is also checked for
> builtin blacklisted hashes, but a following commit make sure that the
> user will notice (at built time) and will fix the configuration if it
> already included errors.
> 
> Check that a blacklist key description starts with a valid prefix and
> then a valid hexadecimal string.
> 
> Cc: David Howells <dhowells@redhat.com>
> Cc: David Woodhouse <dwmw2@infradead.org>
> Signed-off-by: Micka?l Sala?n <mic@linux.microsoft.com>
> Acked-by: Jarkko Sakkinen <jarkko@kernel.org>

In this I'm not as worried about ABI, i.e. you don't have any reason
supply any other data, which doesn't follow these ruels, whereas there
could very well be a script that does format hex "incorrectly".

/Jarkko