Re: [EXT] Re: [PATCH v4 5/5] KEYS: trusted: Introduce support for NXP CAAM-based trusted keys

From: Ahmad Fatoum <a.fatoum@pengutronix.de>
To: Pankaj Gupta <pankaj.gupta@nxp.com>,
	Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Cc: David Gstir <david@sigma-star.at>,
	Aymen Sghaier <aymen.sghaier@nxp.com>,
	"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
	Mimi Zohar <zohar@linux.ibm.com>,
	Jan Luebbe <j.luebbe@pengutronix.de>,
	"keyrings@vger.kernel.org" <keyrings@vger.kernel.org>,
	Udit Agarwal <udit.agarwal@nxp.com>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	Horia Geanta <horia.geanta@nxp.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Richard Weinberger <richard@nod.at>,
	James Morris <jmorris@namei.org>,
	Eric Biggers <ebiggers@kernel.org>,
	Jarkko Sakkinen <jarkko@kernel.org>,
	James Bottomley <jejb@linux.ibm.com>,
	"Serge E. Hallyn" <serge@hallyn.com>,
	"tharvey@gateworks.com" <tharvey@gateworks.com>,
	Franck Lenormand <franck.lenormand@nxp.com>,
	Sumit Garg <sumit.garg@linaro.org>,
	David Howells <dhowells@redhat.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-security-module@vger.kernel.org" 
	<linux-security-module@vger.kernel.org>,
	"linux-crypto@vger.kernel.org" <linux-crypto@vger.kernel.org>,
	"kernel@pengutronix.de" <kernel@pengutronix.de>,
	"linux-integrity@vger.kernel.org"
	<linux-integrity@vger.kernel.org>,
	"David S. Miller" <davem@davemloft.net>
Subject: Re: [EXT] Re: [PATCH v4 5/5] KEYS: trusted: Introduce support for NXP CAAM-based trusted keys
Date: Tue, 22 Feb 2022 12:24:33 +0100	[thread overview]
Message-ID: <db76da34-a40d-4746-5810-316b052acf16@pengutronix.de> (raw)
In-Reply-To: <DU2PR04MB8630EA7DB3AAD9F582EDB75C953B9@DU2PR04MB8630.eurprd04.prod.outlook.com>

Hello Pankaj,

On 22.02.22 05:30, Pankaj Gupta wrote:
> Hi Ahmad,
> 
> 
>> -----Original Message-----
>> From: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
>> Sent: Monday, December 13, 2021 7:11 PM
>> To: Ahmad Fatoum <a.fatoum@pengutronix.de>
>>
>>> For now, this is pointed out in the documentation. If you have a
>>> suggestion on a specific condition we should check and issue a
>>> diagnostic on, I can incorporate it. An exhaustive if
>>> WARN_ON(!secure()) is impossible, but having some warning for
>>> unsuspecting users would indeed be nice.
>>
>> I don't know of any condition that doesn't involve looking at SoC- specific OTP
>> registers - that's what U-Boot does to determine whether HAB is enabled...
>>
> 
> Check the value fetched from the SEC Status Register (SSTA) (Offset 0xFD4h, bit 8,9 => 00b - Non-Secure, 01b - Secure, 10b - Trusted, 11b - Fail), for MOO (Mode of Operation).
> And the warning can be issued accordingly.
> 
> It is to be noted that this register is part of CAAM page0, which might not be accessible to Linux, for all the iMX SoC(s).
> 
> For other SoC(s), this can be added.

Thanks for the pointer. I am only testing this with i.MX, so I'd prefer this
be left as a future exercise for a Layerscape user.

Thanks for your reviews. I collected them on Patches 2/5 and 4/5 for v5.

Cheers,
Ahmad

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