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Date:   Thu, 16 Apr 2020 16:15:29 +1000
From:   Herbert Xu <herbert@gondor.apana.org.au>
To:     Stephan =?iso-8859-1?Q?M=FCller?= <smueller@chronox.de>
Cc:     linux-crypto@vger.kernel.org
Subject: Re: [PATCH 1/2] crypto: Jitter RNG SP800-90B compliance
Message-ID: <20200416061529.GB19267@gondor.apana.org.au>
References: <16276478.9hrKPGv45q@positron.chronox.de>
 <4128830.EzT7ouGoCQ@positron.chronox.de>
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On Sat, Apr 11, 2020 at 09:35:03PM +0200, Stephan M?ller wrote:
>
> @@ -142,7 +143,47 @@ static int jent_kcapi_random(struct crypto_rng *tfm,
>  	int ret = 0;
>  
>  	spin_lock(&rng->jent_lock);
> +
> +	/* Return a permanent error in case we had too many resets in a row. */
> +	if (rng->reset_cnt > (1<<10)) {
> +		ret = -EFAULT;
> +		goto out;
> +	}
> +
>  	ret = jent_read_entropy(rng->entropy_collector, rdata, dlen);
> +
> +	/* Reset RNG in case of health failures */
> +	if (ret < -1) {
> +		pr_warn_ratelimited("Reset Jitter RNG due to health test failure: %s failure\n",
> +				    (ret == -2) ? "Repetition Count Test" :
> +						  "Adaptive Proportion Test");
> +
> +		rng->reset_cnt++;
> +
> +		ret = jent_entropy_init();
> +		if (ret) {
> +			pr_warn_ratelimited("Jitter RNG self-tests failed: %d\n",
> +					    ret);
> +			ret = -EFAULT;
> +			goto out;
> +		}
> +		jent_entropy_collector_free(rng->entropy_collector);
> +		rng->entropy_collector = jent_entropy_collector_alloc(1, 0);

You can't do a GFP_KERNEL allocation inside spin-locks.

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt