From: Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>
To: Linus Walleij <linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
Cc: "linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
<linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
"linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org"
<linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>,
Varun Wadekar <vwadekar-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
Subject: Re: [PATCH] ARM: tegra: throw the unique chip ID into the entropy pool
Date: Fri, 06 Sep 2013 13:09:22 -0600 [thread overview]
Message-ID: <522A2862.9060607@wwwdotorg.org> (raw)
In-Reply-To: <CACRpkdYVUC+MM2SC446k=HC=FwsJMtD6YQa9Hcu8C9eMKMdYng-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
On 09/06/2013 02:53 AM, Linus Walleij wrote:
> On Thu, Sep 5, 2013 at 9:43 PM, Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> wrote:
...
>> Note that the UID value appears to be incorrect on anything other than
>> Tegra20; I'll file an internal bug to track that down.
>
> Hm, that will not affect the kernel entropy pool so much, but
> the crypto driver is in trouble since that seems to be the only
> entropy it's using :-(
Well, it calls getnstimeofday() too, so there's presumably a small
amount of entropy there, unless tegra_aes_rng_reset() gets called at
predictable times, which is probably true.
> If it will return something like a constant, that is actually a quite
> valid case for initializing tmp[1] from the kernel entropy pool
> with get_random_bytes() instead of using UID.
>
> I don't know if the Tegra AES needs that specific initializer
> though (it seems not). Shall I propose a patch?
That sounds reasonable. Perhaps Varun can comment?
WARNING: multiple messages have this Message-ID (diff)
From: swarren@wwwdotorg.org (Stephen Warren)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM: tegra: throw the unique chip ID into the entropy pool
Date: Fri, 06 Sep 2013 13:09:22 -0600 [thread overview]
Message-ID: <522A2862.9060607@wwwdotorg.org> (raw)
In-Reply-To: <CACRpkdYVUC+MM2SC446k=HC=FwsJMtD6YQa9Hcu8C9eMKMdYng@mail.gmail.com>
On 09/06/2013 02:53 AM, Linus Walleij wrote:
> On Thu, Sep 5, 2013 at 9:43 PM, Stephen Warren <swarren@wwwdotorg.org> wrote:
...
>> Note that the UID value appears to be incorrect on anything other than
>> Tegra20; I'll file an internal bug to track that down.
>
> Hm, that will not affect the kernel entropy pool so much, but
> the crypto driver is in trouble since that seems to be the only
> entropy it's using :-(
Well, it calls getnstimeofday() too, so there's presumably a small
amount of entropy there, unless tegra_aes_rng_reset() gets called at
predictable times, which is probably true.
> If it will return something like a constant, that is actually a quite
> valid case for initializing tmp[1] from the kernel entropy pool
> with get_random_bytes() instead of using UID.
>
> I don't know if the Tegra AES needs that specific initializer
> though (it seems not). Shall I propose a patch?
That sounds reasonable. Perhaps Varun can comment?
next prev parent reply other threads:[~2013-09-06 19:09 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-05 15:28 [PATCH] ARM: tegra: throw the unique chip ID into the entropy pool Linus Walleij
2013-09-05 15:28 ` Linus Walleij
[not found] ` <1378394938-1551-1-git-send-email-linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2013-09-05 19:43 ` Stephen Warren
2013-09-05 19:43 ` Stephen Warren
[not found] ` <5228DECA.4090601-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>
2013-09-06 8:53 ` Linus Walleij
2013-09-06 8:53 ` Linus Walleij
[not found] ` <CACRpkdYVUC+MM2SC446k=HC=FwsJMtD6YQa9Hcu8C9eMKMdYng-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-09-06 19:09 ` Stephen Warren [this message]
2013-09-06 19:09 ` Stephen Warren
2013-09-13 16:33 ` Stephen Warren
2013-09-13 16:33 ` Stephen Warren
[not found] ` <52333E56.8060204-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>
2013-09-15 9:24 ` Linus Walleij
2013-09-15 9:24 ` Linus Walleij
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