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Subject: Re: [PATCH v2 6/6] KEYS: trusted: Introduce support for NXP
 CAAM-based trusted keys
To:     Richard Weinberger <richard@nod.at>
Cc:     Jonathan Corbet <corbet@lwn.net>,
        David Howells <dhowells@redhat.com>,
        Jarkko Sakkinen <jarkko@kernel.org>,
        James Bottomley <jejb@linux.ibm.com>,
        Mimi Zohar <zohar@linux.ibm.com>,
        kernel <kernel@pengutronix.de>, James Morris <jmorris@namei.org>,
        "Serge E. Hallyn" <serge@hallyn.com>,
        horia geanta <horia.geanta@nxp.com>,
        aymen sghaier <aymen.sghaier@nxp.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        davem <davem@davemloft.net>, Udit Agarwal <udit.agarwal@nxp.com>,
        Eric Biggers <ebiggers@kernel.org>,
        Jan Luebbe <j.luebbe@pengutronix.de>,
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        Franck Lenormand <franck.lenormand@nxp.com>,
        Sumit Garg <sumit.garg@linaro.org>,
        "open list, ASYMMETRIC KEYS" <keyrings@vger.kernel.org>,
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References: <cover.1dfbb73645d917b3c76d01290804a3410bd9932e.1624364386.git-series.a.fatoum@pengutronix.de>
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From:   Ahmad Fatoum <a.fatoum@pengutronix.de>
Message-ID: <2f608e5a-5a12-6db1-b9bd-a2cd9e3e3671@pengutronix.de>
Date:   Fri, 2 Jul 2021 10:00:05 +0200
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Hello Richard,

On 01.07.21 22:42, Richard Weinberger wrote:
> Ahmad,
> 
> ----- Ursprüngliche Mail -----
>> Von: "Ahmad Fatoum" <a.fatoum@pengutronix.de>
>> +static struct caam_blob_priv *blobifier;
>> +
>> +#define KEYMOD "kernel:trusted"
> 
> I'm still think that hard coding the key modifier is not wise.
> As I said[0], there are folks out there that want to provide their own modifier,
> so it is not only about being binary compatible with other CAAM blob patches in the wild.

I don't think the characterization as a salt is accurate. AFAIU it's more
of a namespace, so blobs being loaded are "type-checked" against the modifier.

> I'll happily implement that feature after your patches got merged but IMHO we should first agree on an interface.
> How about allowing another optional parameter to Opt_new and Opt_load

Sound good to me. pcrlock for TPM trusted keys has the same interface.

I'd prefer the new option to accept strings, not hex though.


> and having a key modifier per struct trusted_key_payload instance?

Ye, possibly a void *backend_data, which other trust sources could leverage
as well. But that should be separate discussion.


Cheers,
Ahmad

> 
> Thanks,
> //richard
> 
> [0]
> https://patchwork.kernel.org/project/linux-crypto/patch/319e558e1bd19b80ad6447c167a2c3942bdafea2.1615914058.git-series.a.fatoum@pengutronix.de/#24085397
> 
> 

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