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Subject: Re: [PATCH v1 0/3] KEYS: trusted: Introduce support for NXP
 CAAM-based trusted keys
To:     Richard Weinberger <richard@nod.at>,
        James Bottomley <jejb@linux.ibm.com>
Cc:     Jarkko Sakkinen <jarkko@kernel.org>,
        horia geanta <horia.geanta@nxp.com>,
        Mimi Zohar <zohar@linux.ibm.com>,
        aymen sghaier <aymen.sghaier@nxp.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        davem <davem@davemloft.net>, kernel <kernel@pengutronix.de>,
        David Howells <dhowells@redhat.com>,
        James Morris <jmorris@namei.org>,
        "Serge E. Hallyn" <serge@hallyn.com>,
        Steffen Trumtrar <s.trumtrar@pengutronix.de>,
        Udit Agarwal <udit.agarwal@nxp.com>,
        Jan Luebbe <j.luebbe@pengutronix.de>,
        david <david@sigma-star.at>,
        Franck Lenormand <franck.lenormand@nxp.com>,
        Sumit Garg <sumit.garg@linaro.org>,
        linux-integrity <linux-integrity@vger.kernel.org>,
        "open list, ASYMMETRIC KEYS" <keyrings@vger.kernel.org>,
        Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        LSM <linux-security-module@vger.kernel.org>
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From:   Ahmad Fatoum <a.fatoum@pengutronix.de>
Message-ID: <f3399480-020e-e3ca-7e7c-eec641fe5afc@pengutronix.de>
Date:   Thu, 1 Apr 2021 12:06:12 +0200
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Hello Richard,

On 31.03.21 21:36, Richard Weinberger wrote:
> James,
> 
> ----- Ursprüngliche Mail -----
>> Von: "James Bottomley" <jejb@linux.ibm.com>
>> Well, yes.  For the TPM, there's a defined ASN.1 format for the keys:
>>
>> https://git.kernel.org/pub/scm/linux/kernel/git/jejb/openssl_tpm2_engine.git/tree/tpm2-asn.h
>>
>> and part of the design of the file is that it's distinguishable either
>> in DER or PEM (by the guards) format so any crypto application can know
>> it's dealing with a TPM key simply by inspecting the file.  I think you
>> need the same thing for CAAM and any other format.
>>
>> We're encouraging new ASN.1 formats to be of the form
>>
>> SEQUENCE {
>>    type   OBJECT IDENTIFIER
>>    ... key specific fields ...
>> }
>>
>> Where you choose a defined OID to represent the key and that means
>> every key even in DER form begins with a unique binary signature.
> 
> I like this idea.
> Ahmad, what do you think?
> 
> That way we could also get rid off the kernel parameter and all the fall back logic,
> given that we find a way to reliable detect TEE blobs too...

Sounds good to me. Sumit, your thoughts on doing this for TEE as well?

> 
> Thanks,
> //richard
> 

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