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From:   Stephan Mueller <smueller@chronox.de>
To:     Herbert Xu <herbert@gondor.apana.org.au>
Cc:     linux-crypto@vger.kernel.org
Subject: Re: [PATCH 1/2] crypto: Jitter RNG SP800-90B compliance
Date:   Thu, 16 Apr 2020 08:56:38 +0200
Message-ID: <2920846.pNu1SyRcjk@tauon.chronox.de>
In-Reply-To: <20200416061529.GB19267@gondor.apana.org.au>
References: <16276478.9hrKPGv45q@positron.chronox.de> <4128830.EzT7ouGoCQ@positron.chronox.de> <20200416061529.GB19267@gondor.apana.org.au>
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Am Donnerstag, 16. April 2020, 08:15:29 CEST schrieb Herbert Xu:

Hi Herbert,

> On Sat, Apr 11, 2020 at 09:35:03PM +0200, Stephan M=FCller wrote:
> > @@ -142,7 +143,47 @@ static int jent_kcapi_random(struct crypto_rng *tf=
m,
> >=20
> >  	int ret =3D 0;
> >  =09
> >  	spin_lock(&rng->jent_lock);
> >=20
> > +
> > +	/* Return a permanent error in case we had too many resets in a row.=
=20
*/
> > +	if (rng->reset_cnt > (1<<10)) {
> > +		ret =3D -EFAULT;
> > +		goto out;
> > +	}
> > +
> >=20
> >  	ret =3D jent_read_entropy(rng->entropy_collector, rdata, dlen);
> >=20
> > +
> > +	/* Reset RNG in case of health failures */
> > +	if (ret < -1) {
> > +		pr_warn_ratelimited("Reset Jitter RNG due to health test=20
failure: %s
> > failure\n", +				    (ret =3D=3D -2) ? "Repetition=20
Count Test" :
> > +						  "Adaptive Proportion Test");
> > +
> > +		rng->reset_cnt++;
> > +
> > +		ret =3D jent_entropy_init();
> > +		if (ret) {
> > +			pr_warn_ratelimited("Jitter RNG self-tests failed:=20
%d\n",
> > +					    ret);
> > +			ret =3D -EFAULT;
> > +			goto out;
> > +		}
> > +		jent_entropy_collector_free(rng->entropy_collector);
> > +		rng->entropy_collector =3D jent_entropy_collector_alloc(1, 0);
>=20
> You can't do a GFP_KERNEL allocation inside spin-locks.

Of course, thanks for pointing that out. I will send an update shortly.

Ciao
Stephan