From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BA144C433FE for ; Mon, 21 Nov 2022 03:23:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229760AbiKUDXD (ORCPT ); Sun, 20 Nov 2022 22:23:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60944 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229498AbiKUDXC (ORCPT ); Sun, 20 Nov 2022 22:23:02 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D5B1D1409D; Sun, 20 Nov 2022 19:23:01 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 684D760E9E; Mon, 21 Nov 2022 03:23:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8DD15C433D6; Mon, 21 Nov 2022 03:22:59 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="UTJ7/TuL" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1669000977; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=DAa5Mzb5unqukMrdaJuHIYWbZgREOXZOVUCauEOi2ps=; b=UTJ7/TuLDD1B+OoUcpwgmLVZFvlUFpMC4gBltI6OxPZ78kzxh84N1P6i4IgYHl0PE4sSYD jPUX0NYXAF5uitLAOsAzthyR438A8ATpqZtkPg6Tk1STEcMJzJSDJWZINZsSPjfmWncLIn stONI7x5GrBtA2+CGCWBLk6Dnh4vnvo= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id ca013759 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Mon, 21 Nov 2022 03:22:57 +0000 (UTC) Date: Mon, 21 Nov 2022 04:22:54 +0100 From: "Jason A. Donenfeld" To: Eric Biggers Cc: linux-kernel@vger.kernel.org, patches@lists.linux.dev, linux-crypto@vger.kernel.org, x86@kernel.org, Thomas Gleixner , Greg Kroah-Hartman , Adhemerval Zanella Netto , Carlos O'Donell Subject: Re: [PATCH v5 2/3] random: introduce generic vDSO getrandom() implementation Message-ID: References: <20221119120929.2963813-1-Jason@zx2c4.com> <20221119120929.2963813-3-Jason@zx2c4.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org On Sun, Nov 20, 2022 at 02:43:31AM +0100, Jason A. Donenfeld wrote: > On Sun, Nov 20, 2022 at 01:53:53AM +0100, Jason A. Donenfeld wrote: > > shouldn't fork or something, but that seems disappointing. Or more state > > could be allocated in the zeroing region, to hold a chacha state, so > > another 64 bytes, which would be sort of unfortunate. Or something else? > > I'd be interested to hear your impression of this quandary. > > Another 128 bytes, actually. And the current chacha in there isn't > cleaning up its stack as one might hope. So maybe the cleanest solution > would be to just bite the bullet and allocate another 128 bytes per > state and make a mini chacha that operates over that? (And I guess hope > it doesn't need to spill and such...) I've got it implemented without using any stack now. Wasn't so bad. So all of the additional concerns I added will be addressed in v+1. Jason