[WireGuard] [PATCH] poly1305: generic C can be faster on chips with slow unaligned access

Jason A. Donenfeld Jason at zx2c4.com
Mon Nov 7 20:02:35 CET 2016

On Mon, Nov 7, 2016 at 7:26 PM, Eric Biggers <ebiggers at 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.

More information about the WireGuard mailing list