From: Tzung-Bi Shih <tzungbi@google.com>
To: Benson Leung <bleung@google.com>
Cc: ALSA development <alsa-devel@alsa-project.org>,
Herbert Xu <herbert@gondor.apana.org.au>,
Arnd Bergmann <arnd@arndb.de>,
Liam Girdwood <lgirdwood@gmail.com>,
Eric Biggers <ebiggers@kernel.org>,
Guenter Roeck <groeck@chromium.org>,
Mark Brown <broonie@kernel.org>,
Enric Balletbo i Serra <enric.balletbo@collabora.com>,
Benson Leung <bleung@chromium.org>,
Ard Biesheuvel <ardb@kernel.org>,
Cheng-Yi Chiang <cychiang@chromium.org>
Subject: Re: [PATCH] SoC: cros_ec_codec: switch to library API for SHA-256
Date: Fri, 15 May 2020 10:40:19 +0800 [thread overview]
Message-ID: <CA+Px+wWps5d5qpL_0ed2jrD5bMKgd=8p1rbcRH28J-1SpgVz0Q@mail.gmail.com> (raw)
In-Reply-To: <20200514162548.GA141824@google.com>
On Fri, May 15, 2020 at 12:26 AM Benson Leung <bleung@google.com> wrote:
> On Thu, May 14, 2020 at 06:18:47PM +0200, Ard Biesheuvel wrote:
> > The CrOS EC codec driver uses SHA-256 explicitly, and not in a
> > performance critical manner, so there is really no point in using
> > the dynamic SHASH crypto API here. Let's switch to the library API
> > instead.
Pardon me if I don't understand it precisely. What is the difference
between the two APIs? Suppose it should calculate the same SHA256
hash with the same binary blob after switching to library API?
> > Looking at the code, I was wondering if the SHA-256 is really required
> > here? It looks like it is using it as some kind of fingerprint to decide
> > whether the provided file is identical to the one that has already been
> > loaded. If this is the case, we should probably just use CRC32 instead.
No, the binary blob carries data and possibly code. We are not only
using the hash as a fingerprint but also an integrity check.
> > Also, do we really need to wipe the context struct? Is there any security
> > sensitive data in there?
No, not necessary as far as I know.
next prev parent reply other threads:[~2020-05-15 2:41 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-14 16:18 [PATCH] SoC: cros_ec_codec: switch to library API for SHA-256 Ard Biesheuvel
2020-05-14 16:25 ` Benson Leung
2020-05-15 2:40 ` Tzung-Bi Shih [this message]
2020-05-15 6:04 ` Ard Biesheuvel
2020-05-15 6:40 ` Tzung-Bi Shih
2020-05-15 6:48 ` Tzung-Bi Shih
2020-05-15 6:50 ` Ard Biesheuvel
2020-05-15 9:02 ` Tzung-Bi Shih
2020-05-15 9:08 ` Ard Biesheuvel
2020-05-15 9:47 ` Mark Brown
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