From: Tzung-Bi Shih <tzungbi@google.com>
To: Ard Biesheuvel <ardb@kernel.org>
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@google.com>,
Benson Leung <bleung@chromium.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 14:40:35 +0800 [thread overview]
Message-ID: <CA+Px+wV1w4gFcV+ABtK44ec0aPTT9APkpFMUyLMUh5tStgHstQ@mail.gmail.com> (raw)
In-Reply-To: <CAMj1kXE2KsCoDrH5nY7vmGA6K4ekDTX=v-stj1uh7UHNqquJMg@mail.gmail.com>
On Fri, May 15, 2020 at 2:04 PM Ard Biesheuvel <ardb@kernel.org> wrote:
> > > > 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.
> >
>
> But does it have to be cryptographically strong? Why is CRC32 not sufficient?
Please see https://crrev.com/c/1490800/26/include/ec_commands.h#4744
for our original decision.
Also would like to let you know that the data path to call
calculate_sha256( ) is in-frequent (1~2 times) if you think it is too
expensive to use SHA256.
next prev parent reply other threads:[~2020-05-15 6:41 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
2020-05-15 6:04 ` Ard Biesheuvel
2020-05-15 6:40 ` Tzung-Bi Shih [this message]
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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