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Date: Mon, 11 Mar 2024 22:07:19 +0200
Message-Id: <CZR6X7KLX6NC.1BH2NHDTNL3C@kernel.org>
Cc: "Mimi Zohar" <zohar@linux.ibm.com>, "James Bottomley"
 <jejb@linux.ibm.com>, "Herbert Xu" <herbert@gondor.apana.org.au>, "David S.
 Miller" <davem@davemloft.net>, "Shawn Guo" <shawnguo@kernel.org>, "Jonathan
 Corbet" <corbet@lwn.net>, "Sascha Hauer" <s.hauer@pengutronix.de>,
 "kernel@pengutronix.de" <kernel@pengutronix.de>, "Fabio Estevam"
 <festevam@gmail.com>, "NXP Linux Team" <linux-imx@nxp.com>, "Ahmad Fatoum"
 <a.fatoum@pengutronix.de>, "sigma star Kernel Team"
 <upstream+dcp@sigma-star.at>, "David Howells" <dhowells@redhat.com>, "Li
 Yang" <leoyang.li@nxp.com>, "Paul Moore" <paul@paul-moore.com>, "James
 Morris" <jmorris@namei.org>, "Serge E. Hallyn" <serge@hallyn.com>, "Paul E.
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 <linux-security-module@vger.kernel.org>, "Richard Weinberger"
 <richard@nod.at>, "David Oberhollenzer" <david.oberhollenzer@sigma-star.at>
Subject: Re: [PATCH v6 3/6] KEYS: trusted: Introduce NXP DCP-backed trusted
 keys
From: "Jarkko Sakkinen" <jarkko@kernel.org>
To: "David Gstir" <david@sigma-star.at>
References: <20240307153842.80033-1-david@sigma-star.at>
 <20240307153842.80033-4-david@sigma-star.at>
 <CZNRMR5YZPQO.1QBLW62A6S840@kernel.org>
 <655221B7-634C-4493-A781-CF014DFFC8BF@sigma-star.at>
In-Reply-To: <655221B7-634C-4493-A781-CF014DFFC8BF@sigma-star.at>

On Fri Mar 8, 2024 at 9:17 AM EET, David Gstir wrote:
> Hi Jarkko,
>
> > On 07.03.2024, at 20:30, Jarkko Sakkinen <jarkko@kernel.org> wrote:
>
> [...]
>
> >> +
> >> +static int trusted_dcp_init(void)
> >> +{
> >> + int ret;
> >> +
> >> + if (use_otp_key)
> >> + pr_info("Using DCP OTP key\n");
> >> +
> >> + ret =3D test_for_zero_key();
> >> + if (ret) {
> >> + pr_err("Test for zero'ed keys failed: %i\n", ret);
> >=20
> > I'm not sure whether this should err or warn.
> >=20
> > What sort of situations can cause the test the fail (e.g.
> > adversary/interposer, bad configuration etc.).
>
> This occurs when the hardware is not in "secure mode". I.e. it=E2=80=99s =
a bad configuration issue.
> Once the board is properly configured, this will never trigger again.
> Do you think a warning is better for this then?

Bad configuration is not unexpected configuration so it cannot possibly
be an error situation as far as Linux is considered. So warning is=20
appropriate here I'd figure.

BR, Jarkko