Re: [PATCH crypto 2/2] lib/crypto: blake2s: move hmac construction into wireguard

From: Eric Biggers
Date: Wed Jan 12 2022 - 13:36:16 EST


On Tue, Jan 11, 2022 at 02:49:34PM +0100, Jason A. Donenfeld wrote:
> Basically nobody should use blake2s in an HMAC construction; it already
> has a keyed variant. But for unfortunately historical reasons, Noise,
> used by WireGuard, uses HKDF quite strictly, which means we have to use
> this. Because this really shouldn't be used by others, this commit moves
> it into wireguard's noise.c locally, so that kernels that aren't using
> WireGuard don't get this superfluous code baked in. On m68k systems,
> this shaves off ~314 bytes.
>
> Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
> Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
> Cc: Ard Biesheuvel <ardb@xxxxxxxxxx>
> Cc: netdev@xxxxxxxxxxxxxxx
> Cc: wireguard@xxxxxxxxxxxxxxx
> Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx>
> ---

Reviewed-by: Eric Biggers <ebiggers@xxxxxxxxxx>

- Eric