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From: "George Spelvin" <linux@horizon.com>
To: hannes@stressinduktion.org, linux@horizon.com
Cc: dborkman@redhat.com, herbert@gondor.apana.org.au,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
	tgraf@suug.ch
Subject: Re: Where exactly will arch_fast_hash be used
Date: 7 Dec 2014 08:30:56 -0500	[thread overview]
Message-ID: <20141207133056.25209.qmail@ns.horizon.com> (raw)
In-Reply-To: <1417958080.17658.32.camel@localhost>

Thanks for the encouragement!

> Please consider xfs, too.
> AFAIK xfs doesn't seed their hashing so far and the hashing function is
> pretty weak. One example:
> http://marc.info/?l=linux-xfs&m=139590613002926&w=2

Is that something that *can* be changed without breaking the
disk format?  SipHash is explicitly *not* designed to be secure as
an unkeyed hash in the way that SHA-type algorithms are.

What it's designed to do is provide second preimage resistance
of its output, or a function (like modular reduction) of its output,
against an attacker who doesn't know the secret seed.

> Ack. If we want to use it in the networking stack we should be able to
> use it without a dependency to the crypto framework.

Already understood.  My big question is whether a single function call
is okay or we need something inlinable.

  reply	other threads:[~2014-12-07 13:30 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-12-07  5:20 Where exactly will arch_fast_hash be used George Spelvin
2014-12-07  9:28 ` Herbert Xu
2014-12-07 10:02   ` George Spelvin
2014-12-07 12:51     ` Herbert Xu
2014-12-07 13:23       ` George Spelvin
2014-12-07 14:06         ` Hannes Frederic Sowa
2014-12-07 21:33           ` George Spelvin
2014-12-08 11:25             ` Hannes Frederic Sowa
2014-12-08 16:19               ` George Spelvin
2014-12-08 16:32                 ` Hannes Frederic Sowa
2014-12-09 14:24         ` Herbert Xu
2014-12-07 13:14 ` Hannes Frederic Sowa
2014-12-07 13:30   ` George Spelvin [this message]
2014-12-07 13:41     ` Hannes Frederic Sowa
2014-12-07 13:52       ` Hannes Frederic Sowa
  -- strict thread matches above, loose matches on Subject: below --
2014-12-04  8:11 Herbert Xu
2014-12-04 12:34 ` Hannes Frederic Sowa
2014-12-04 13:14   ` Daniel Borkmann
2014-12-04 15:26 ` Thomas Graf
2014-12-04 15:29   ` Herbert Xu
2014-12-04 15:39     ` Thomas Graf
2014-12-04 15:43       ` Daniel Borkmann
2014-12-04 15:47         ` Herbert Xu
2014-12-04 15:51           ` Daniel Borkmann
2014-12-04 15:56           ` David Laight
2014-12-04 16:10             ` Herbert Xu

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