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From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: Eric Biggers <ebiggers@google.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>,
	Martin Willi <martin@strongswan.org>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-crypto@vger.kernel.org, David Miller <davem@davemloft.net>,
	WireGuard mailing list <wireguard@lists.zx2c4.com>
Subject: Re: [WireGuard] [PATCH] poly1305: generic C can be faster on chips with slow unaligned access
Date: Mon, 7 Nov 2016 20:02:35 +0100	[thread overview]
Message-ID: <CAHmME9rzBST8Lqapzykwf2rUyxLXuyOF0wX+Sy259Qtx9a4YSg@mail.gmail.com> (raw)
In-Reply-To: <20161107182646.GA34388@google.com>

On Mon, Nov 7, 2016 at 7:26 PM, Eric Biggers <ebiggers@google.com> wrote:
>
> I was not referring to any users in particular, only what users could do.  As an
> example, if you did crypto_shash_update() with 32, 15, then 17 bytes, and the
> underlying algorithm is poly1305-generic, the last block would end up
> misaligned.  This doesn't appear possible with your pseudocode because it only
> passes in multiples of the block size until the very end.  However I don't see
> it claimed anywhere that shash API users have to do that.

Actually it appears that crypto/poly1305_generic.c already buffers
incoming blocks to a buffer that definitely looks aligned, to prevent
this condition!

I'll submit a v2 with only the inner unaligned operations changed.

  reply	other threads:[~2016-11-07 19:00 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CAHmME9ogYTGFaNDt1CD0FxEHxDzVhNX=AN3_PH3t=0zREGgYPA@mail.gmail.com>
     [not found] ` <20161103004934.GA30775@gondor.apana.org.au>
     [not found]   ` <CAHmME9oL-pOWWXXFhJz1vSm5ftnSfmYrquGbH0acapgEL=c4Ew@mail.gmail.com>
     [not found]     ` <20161103.130852.1456848512897088071.davem@davemloft.net>
2016-11-03 22:20       ` Jason A. Donenfeld
2016-11-04 17:37         ` Eric Biggers
2016-11-07 18:08           ` Jason A. Donenfeld
2016-11-07 18:23             ` Jason A. Donenfeld
2016-11-07 18:26             ` Eric Biggers
2016-11-07 19:02               ` Jason A. Donenfeld [this message]
2016-11-07 19:25                 ` Eric Biggers
2016-11-07 19:41                   ` Jason A. Donenfeld

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