From: Andi Kleen <andi@firstfloor.org>
To: roel kluin <roel.kluin@gmail.com>
Cc: David Miller <davem@davemloft.net>,
herbert@gondor.apana.org.au, mikpe@it.uu.se,
linux-crypto@vger.kernel.org, akpm@linux-foundation.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] sha: prevent removal of memset as dead store in sha1_update()
Date: Fri, 26 Feb 2010 12:55:14 +0100 [thread overview]
Message-ID: <87sk8oqkil.fsf@basil.nowhere.org> (raw)
In-Reply-To: <25e057c01002250731q68bb9e28ld009163f2a009f48@mail.gmail.com> (roel kluin's message of "Thu, 25 Feb 2010 16:31:36 +0100")
roel kluin <roel.kluin@gmail.com> writes:
>> And it's wrong because the reason the memset() is there seems to be
>> to clear out key information that might exist kernel stack so that
>> it's more difficult for rogue code to get at things.
>
> If the memset is optimized away then the clear out does not occur. Do you
> know a different way to fix this? I observed this with:
You could always cast to volatile before memsetting?
-Andi
--
ak@linux.intel.com -- Speaking for myself only.
next prev parent reply other threads:[~2010-02-26 11:55 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-25 15:10 [PATCH] sha: prevent removal of memset as dead store in sha1_update() Roel Kluin
2010-02-25 15:10 ` Roel Kluin
2010-02-25 15:17 ` David Miller
2010-02-25 15:31 ` roel kluin
2010-02-25 15:31 ` roel kluin
2010-02-25 15:37 ` David Miller
2010-02-26 11:55 ` Andi Kleen [this message]
2010-02-26 14:20 ` Mikael Pettersson
2010-02-26 15:46 ` Mikael Pettersson
2010-02-26 15:55 ` Andi Kleen
2010-02-25 15:56 ` Mikael Pettersson
2010-02-25 16:16 ` Pekka Enberg
2010-02-25 16:16 ` Pekka Enberg
2010-02-25 16:29 ` Mikael Pettersson
2010-02-25 16:29 ` Mikael Pettersson
2010-02-25 16:33 ` roel kluin
2010-02-25 16:33 ` roel kluin
2010-02-25 17:06 ` roel kluin
2010-02-25 17:06 ` roel kluin
2010-02-25 16:33 ` Brian Gerst
2010-02-25 16:33 ` Brian Gerst
2010-02-25 17:09 ` Mikael Pettersson
2010-02-25 17:09 ` Mikael Pettersson
2010-02-25 17:32 ` Brian Gerst
2010-02-25 17:32 ` Brian Gerst
2010-02-25 19:47 ` Roel Kluin
2010-02-25 20:43 ` Roel Kluin
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