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 X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 204DFC48BD7 for ; Thu, 27 Jun 2019 17:18:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E973520659 for ; Thu, 27 Jun 2019 17:18:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726514AbfF0RSy (ORCPT ); Thu, 27 Jun 2019 13:18:54 -0400 Received: from outgoing-auth-1.mit.edu ([18.9.28.11]:38464 "EHLO outgoing.mit.edu" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726315AbfF0RSy (ORCPT ); Thu, 27 Jun 2019 13:18:54 -0400 Received: from callcc.thunk.org (guestnat-104-133-0-109.corp.google.com [104.133.0.109] (may be forged)) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id x5RHIeeq021689 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 27 Jun 2019 13:18:41 -0400 Received: by callcc.thunk.org (Postfix, from userid 15806) id 687B842002E; Thu, 27 Jun 2019 13:18:40 -0400 (EDT) Date: Thu, 27 Jun 2019 13:18:40 -0400 From: "Theodore Ts'o" To: Eric Biggers Cc: linux-fscrypt@vger.kernel.org, linux-crypto@vger.kernel.org, Ard Biesheuvel , Richard Weinberger Subject: Re: [PATCH] fscrypt: remove selection of CONFIG_CRYPTO_SHA256 Message-ID: <20190627171840.GB31445@mit.edu> References: <20190620181505.225232-1-ebiggers@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190620181505.225232-1-ebiggers@kernel.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org On Thu, Jun 20, 2019 at 11:15:05AM -0700, Eric Biggers wrote: > From: Eric Biggers > > fscrypt only uses SHA-256 for AES-128-CBC-ESSIV, which isn't the default > and is only recommended on platforms that have hardware accelerated > AES-CBC but not AES-XTS. There's no link-time dependency, since SHA-256 > is requested via the crypto API on first use. > > To reduce bloat, we should limit FS_ENCRYPTION to selecting the default > algorithms only. SHA-256 by itself isn't that much bloat, but it's > being discussed to move ESSIV into a crypto API template, which would > incidentally bring in other things like "authenc" support, which would > all end up being built-in since FS_ENCRYPTION is now a bool. > > For Adiantum encryption we already just document that users who want to > use it have to enable CONFIG_CRYPTO_ADIANTUM themselves. So, let's do > the same for AES-128-CBC-ESSIV and CONFIG_CRYPTO_SHA256. > > Signed-off-by: Eric Biggers Reviewed-by: Theodore Ts'o