From: "Stephan Müller" <smueller@chronox.de>
To: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Kukjin Kim <kgene@kernel.org>,
Javier Martinez Canillas <javier@osg.samsung.com>,
Matt Mackall <mpm@selenic.com>,
Herbert Xu <herbert@gondor.apana.org.au>,
"David S. Miller" <davem@davemloft.net>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-samsung-soc@vger.kernel.org, linux-crypto@vger.kernel.org,
Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
Arnd Bergmann <arnd@arndb.de>, Olof Johansson <olof@lixom.net>
Subject: Re: [PATCH v3 1/3] crypto: hw_random - Add new Exynos RNG driver
Date: Sun, 26 Mar 2017 19:11:28 +0200 [thread overview]
Message-ID: <2736911.EcZSki4vB1@positron.chronox.de> (raw)
In-Reply-To: <20170325162654.3827-2-krzk@kernel.org>
Am Samstag, 25. März 2017, 17:26:52 CEST schrieb Krzysztof Kozlowski:
Hi Krzysztof,
> +static int exynos_rng_set_seed(struct exynos_rng_dev *rng,
> + const u8 *seed, unsigned int slen)
> +{
> + u32 val;
> + int i;
> +
> + dev_dbg(rng->dev, "Seeding with %u bytes\n", slen);
> +
> + if (slen < EXYNOS_RNG_SEED_SIZE) {
> + dev_warn(rng->dev, "Seed too short (only %u bytes)\n", slen);
> + return -EINVAL;
> + }
> +
> + for (i = 0 ; i < EXYNOS_RNG_SEED_REGS ; i++) {
> + val = seed[i * 4] << 24;
> + val |= seed[i * 4 + 1] << 16;
> + val |= seed[i * 4 + 2] << 8;
> + val |= seed[i * 4 + 3] << 0;
> +
> + exynos_rng_writel(rng, val, EXYNOS_RNG_SEED(i));
> + }
Would it make sense to add another outer loop here to allow all of slen to be
injected into the DRNG? Note, in some cases, a user wants to add more seed
into the DRNG than the actual seed size. In this case, the DRNG acts as a
compression operation of entropy. This is used when the entropy-to-data ratio
is not 1:1. In a lot of cases, users have a seed which has less entropy in
bits per data bit.
Ciao
Stephan
WARNING: multiple messages have this Message-ID (diff)
From: smueller@chronox.de (Stephan Müller)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 1/3] crypto: hw_random - Add new Exynos RNG driver
Date: Sun, 26 Mar 2017 19:11:28 +0200 [thread overview]
Message-ID: <2736911.EcZSki4vB1@positron.chronox.de> (raw)
In-Reply-To: <20170325162654.3827-2-krzk@kernel.org>
Am Samstag, 25. M?rz 2017, 17:26:52 CEST schrieb Krzysztof Kozlowski:
Hi Krzysztof,
> +static int exynos_rng_set_seed(struct exynos_rng_dev *rng,
> + const u8 *seed, unsigned int slen)
> +{
> + u32 val;
> + int i;
> +
> + dev_dbg(rng->dev, "Seeding with %u bytes\n", slen);
> +
> + if (slen < EXYNOS_RNG_SEED_SIZE) {
> + dev_warn(rng->dev, "Seed too short (only %u bytes)\n", slen);
> + return -EINVAL;
> + }
> +
> + for (i = 0 ; i < EXYNOS_RNG_SEED_REGS ; i++) {
> + val = seed[i * 4] << 24;
> + val |= seed[i * 4 + 1] << 16;
> + val |= seed[i * 4 + 2] << 8;
> + val |= seed[i * 4 + 3] << 0;
> +
> + exynos_rng_writel(rng, val, EXYNOS_RNG_SEED(i));
> + }
Would it make sense to add another outer loop here to allow all of slen to be
injected into the DRNG? Note, in some cases, a user wants to add more seed
into the DRNG than the actual seed size. In this case, the DRNG acts as a
compression operation of entropy. This is used when the entropy-to-data ratio
is not 1:1. In a lot of cases, users have a seed which has less entropy in
bits per data bit.
Ciao
Stephan
next prev parent reply other threads:[~2017-03-26 17:11 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-25 16:26 [PATCH v3 0/3] crypto: hw_random - Add new Exynos RNG driver Krzysztof Kozlowski
2017-03-25 16:26 ` Krzysztof Kozlowski
2017-03-25 16:26 ` Krzysztof Kozlowski
2017-03-25 16:26 ` [PATCH v3 1/3] " Krzysztof Kozlowski
2017-03-25 16:26 ` Krzysztof Kozlowski
2017-03-26 15:20 ` PrasannaKumar Muralidharan
2017-03-26 15:20 ` PrasannaKumar Muralidharan
2017-03-26 15:20 ` PrasannaKumar Muralidharan
2017-03-26 16:01 ` Krzysztof Kozlowski
2017-03-26 16:01 ` Krzysztof Kozlowski
2017-03-26 16:01 ` Krzysztof Kozlowski
2017-03-26 16:05 ` Stephan Müller
2017-03-26 16:05 ` Stephan Müller
2017-03-26 16:05 ` Stephan Müller
2017-03-26 16:46 ` PrasannaKumar Muralidharan
2017-03-26 16:46 ` PrasannaKumar Muralidharan
2017-03-26 17:05 ` Stephan Müller
2017-03-26 17:05 ` Stephan Müller
2017-03-26 18:09 ` Krzysztof Kozlowski
2017-03-26 18:09 ` Krzysztof Kozlowski
2017-03-26 18:09 ` Krzysztof Kozlowski
2017-03-26 17:11 ` Stephan Müller [this message]
2017-03-26 17:11 ` Stephan Müller
2017-03-26 18:00 ` Krzysztof Kozlowski
2017-03-26 18:00 ` Krzysztof Kozlowski
2017-03-26 18:00 ` Krzysztof Kozlowski
2017-03-26 21:25 ` Stephan Müller
2017-03-26 21:25 ` Stephan Müller
2017-03-27 4:23 ` PrasannaKumar Muralidharan
2017-03-27 4:23 ` PrasannaKumar Muralidharan
2017-03-27 4:23 ` PrasannaKumar Muralidharan
2017-03-27 13:53 ` Stephan Müller
2017-03-27 13:53 ` Stephan Müller
2017-03-27 13:53 ` Stephan Müller
2017-03-28 16:48 ` Krzysztof Kozlowski
2017-03-28 16:48 ` Krzysztof Kozlowski
2017-03-28 17:41 ` Stephan Müller
2017-03-28 17:41 ` Stephan Müller
2017-03-28 17:43 ` Krzysztof Kozlowski
2017-03-28 17:43 ` Krzysztof Kozlowski
2017-03-25 16:26 ` [PATCH v3 2/3] ARM: exynos_defconfig: Enable Exynos RNG and user-space crypto API Krzysztof Kozlowski
2017-03-25 16:26 ` Krzysztof Kozlowski
2017-03-25 16:26 ` [PATCH v3 3/3] ARM: multi_v7_defconfig: " Krzysztof Kozlowski
2017-03-25 16:26 ` Krzysztof Kozlowski
2017-03-25 16:32 ` [PATCH v3 0/3] crypto: hw_random - Add new Exynos RNG driver Stephan Müller
2017-03-25 16:32 ` Stephan Müller
2017-03-25 16:32 ` Stephan Müller
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