From:   Ahmad Fatoum <a.fatoum@pengutronix.de>
Subject: Re: [PATCH v4 4/5] crypto: caam - add in-kernel interface for blob
 generator
To:     Jarkko Sakkinen <jarkko@kernel.org>
Cc:     =?UTF-8?Q?Horia_Geant=c4=83?= <horia.geanta@nxp.com>,
        Aymen Sghaier <aymen.sghaier@nxp.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        "David S. Miller" <davem@davemloft.net>, kernel@pengutronix.de,
        David Gstir <david@sigma-star.at>,
        Tim Harvey <tharvey@gateworks.com>,
        James Bottomley <jejb@linux.ibm.com>,
        Mimi Zohar <zohar@linux.ibm.com>,
        David Howells <dhowells@redhat.com>,
        James Morris <jmorris@namei.org>,
        Eric Biggers <ebiggers@kernel.org>,
        "Serge E. Hallyn" <serge@hallyn.com>,
        Udit Agarwal <udit.agarwal@nxp.com>,
        Jan Luebbe <j.luebbe@pengutronix.de>,
        Richard Weinberger <richard@nod.at>,
        Franck LENORMAND <franck.lenormand@nxp.com>,
        Sumit Garg <sumit.garg@linaro.org>,
        linux-integrity@vger.kernel.org, keyrings@vger.kernel.org,
        linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-security-module@vger.kernel.org
References: <cover.8f40b6d1b93adc80aed2cac29a134f7a7fb5ee98.1633946449.git-series.a.fatoum@pengutronix.de>
 <3ea6e5c37559eddfdc51f26c4dff0abbbc894839.1633946449.git-series.a.fatoum@pengutronix.de>
 <YawFYFV8xGIPZvUJ@iki.fi>
Message-ID: <3e33a215-12d2-da30-d1e1-2fde753a7a0a@pengutronix.de>
Date:   Mon, 13 Dec 2021 11:34:39 +0100
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Hello Jarkko,

On 05.12.21 01:18, Jarkko Sakkinen wrote:
> On Mon, Oct 11, 2021 at 12:02:37PM +0200, Ahmad Fatoum wrote:
>> The CAAM can be used to protect user-defined data across system reboot:
>>
>>   - When the system is fused and boots into secure state, the master
>>     key is a unique never-disclosed device-specific key
>>   - random key is encrypted by key derived from master key
>>   - data is encrypted using the random key
>>   - encrypted data and its encrypted random key are stored alongside
>>   - This blob can now be safely stored in non-volatile memory
>>
>> On next power-on:
>>   - blob is loaded into CAAM
>>   - CAAM writes decrypted data either into memory or key register
>>
>> Add functions to realize encrypting and decrypting into memory alongside
>> the CAAM driver.
>>
>> They will be used in a later commit as a source for the trusted key
>> seal/unseal mechanism.
>>
>> Reviewed-by: David Gstir <david@sigma-star.at>
>> Tested-By: Tim Harvey <tharvey@gateworks.com>
>> Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
>> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> 
> What is CAAM? This is missing.

That's Crypto Accelerator on NXP SoCs. There is a description in the cover
letter and in the follow-up patch wiring this into the new trusted key
source. I didn't elaborate on this here as this patch touches
drivers/crypto/caam and I assumed familiarity.

For v5, I can add some extra info:

"The NXP Cryptographic Acceleration and Assurance Module (CAAM)
 can be used to protect user-defined data across system reboot..."

Sounds good? Does the last patch in the series look ok to you?

Cheers,
Ahmad

> 
> /Jarkko
> 


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