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=-2.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 564D1C3F2C6 for ; Tue, 3 Mar 2020 12:35:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2D25020842 for ; Tue, 3 Mar 2020 12:35:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="GHga60VN" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728525AbgCCMfz (ORCPT ); Tue, 3 Mar 2020 07:35:55 -0500 Received: from mail-wm1-f41.google.com ([209.85.128.41]:40849 "EHLO mail-wm1-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728415AbgCCMfz (ORCPT ); Tue, 3 Mar 2020 07:35:55 -0500 Received: by mail-wm1-f41.google.com with SMTP id e26so2653940wme.5; Tue, 03 Mar 2020 04:35:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=rz2M9V+ocKeCKBO1DTovHWBHdLHnzUuWHLb/2ndomPg=; b=GHga60VNe5FeroqHZ/v9n4E2vp3rgvzrlblLNbqORO7SNQfyDjLW5AON9gM6Uwb6xQ NuH/FL2Z7dX+BUNOj+YEiLciP9jJgIftKg/HXqpl1XainX2ArMEwtLj+EimmO0+IEUiv hhqudlhUeULciWh1yPbxzzyAhuFz4if+ORNrQIbSUOo503U5vshuNOiOf2byKeefwgoH oNp3wtIuF18eqbb4I51cXPZoPk6KmLKzwYAu0DuDR9lw4L9zQHm2L1CsgUGinhEIaXJ2 WCl3PuFlmwE8n0h5hym+lNEOR9OhS6f7rEVjMGcXFDAzGqmq2xBKNYXWbLJfhVWyYTP0 vpIg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=rz2M9V+ocKeCKBO1DTovHWBHdLHnzUuWHLb/2ndomPg=; b=VZ4mlvVbGmrXyBUPW26a4RijXHEb3mGS0EvxbopNnbZdDLcReWhtlyeh2WE1crm669 Xc1sjOKuBCPLsCPifR6cjctmzP/PD4++yD/yqbj0QdrRqKJDx+u7tyC0pCs77JhVH3+7 q/0NQNSLZuBB2VB8g7ojlTTgul2ucaXtIxInW2TsH0Dx/cGDkQ4BqynqtbYlYndOYeNJ 7iAQLrbwp1A2lzlexkPbp6CPu9qmMTD4ygZRGB1sQ8vsUZEL0XlyN5Rwumw6VF2/ujMP 3J/Hn0pW6iDrN1wby7C0p+TPunkDV0/7t8W435HG4ilY9A/Zc3ZgnBzTeooO9smSovA/ Lnbw== X-Gm-Message-State: ANhLgQ2lGA9Olt1KoGWzsdGffIs8yNYKsW/qwcVxbypUEqw8GdkdqnlP 87zjiHMOm3XH5jfb/Nt1iWGmF37d X-Google-Smtp-Source: ADFU+vufeWSmB8RAOO4F2s3ATVOHiD1EGO8AhsT03Q02Af0id3T2mAwbnruorwSjWm0o//ef43PtVg== X-Received: by 2002:a7b:c204:: with SMTP id x4mr4179246wmi.20.1583238952930; Tue, 03 Mar 2020 04:35:52 -0800 (PST) Received: from [10.34.28.108] (nat-pool-brq-t.redhat.com. [213.175.37.10]) by smtp.gmail.com with ESMTPSA id k126sm3401852wme.4.2020.03.03.04.35.51 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 03 Mar 2020 04:35:52 -0800 (PST) Subject: Re: [RFC] crypto: xts - limit accepted key length To: "Van Leeuwen, Pascal" , Andrei Botila , Herbert Xu , "David S. Miller" Cc: "linux-crypto@vger.kernel.org" , "linux-kernel@vger.kernel.org" References: From: Milan Broz Message-ID: <72e1866a-9202-8d5b-f67b-8d9a63d888a7@gmail.com> Date: Tue, 3 Mar 2020 13:35:51 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org On 02/03/2020 09:33, Van Leeuwen, Pascal wrote: > Hmm ... in principle IEEE-1619 also defines XTS *only* for AES. So by that same > reasoning, you should also not allow any usage of XTS beyond AES. Yet it is > actually being actively used(?) with other ciphers in the Linux kernel. Just FYI - yes, it is actively used with other ciphers. There is a lot of LUKS devices that use Serpent or Twofish with XTS mode. The same for TrueCrypt/VeraCrypt, here sometimes it is used also in cipher chain (both native binaries or cryptsetup code use dm-crypt with crypto API here). XTS mode is designed for storage encryption only - and at least for disk encryption I have never seen request for 192bit keys... Milan