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=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 B3650C6778D for ; Tue, 11 Sep 2018 13:53:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 75DC22086E for ; Tue, 11 Sep 2018 13:53:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 75DC22086E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=alien8.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727833AbeIKSwy (ORCPT ); Tue, 11 Sep 2018 14:52:54 -0400 Received: from mail.skyhub.de ([5.9.137.197]:43876 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726983AbeIKSwy (ORCPT ); Tue, 11 Sep 2018 14:52:54 -0400 X-Virus-Scanned: Nedap ESD1 at mail.skyhub.de Received: from mail.skyhub.de ([127.0.0.1]) by localhost (blast.alien8.de [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id o2vLaCbP6y2M; Tue, 11 Sep 2018 15:53:27 +0200 (CEST) Received: from zn.tnic (p200300EC2BC6F600329C23FFFEA6A903.dip0.t-ipconnect.de [IPv6:2003:ec:2bc6:f600:329c:23ff:fea6:a903]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 2527B1EC0181; Tue, 11 Sep 2018 15:53:27 +0200 (CEST) Date: Tue, 11 Sep 2018 15:53:25 +0200 From: Borislav Petkov To: Brijesh Singh Cc: linux-crypto@vger.kernel.org, thomas.lendacky@amd.com, Gary Hook , Herbert Xu , linux-kernel@vger.kernel.org Subject: Re: [PATCH crypto-2.6] crypto: ccp: add timeout support in the SEV command Message-ID: <20180911135325.GI12094@zn.tnic> References: <1534367485-4386-1-git-send-email-brijesh.singh@amd.com> <1534367485-4386-2-git-send-email-brijesh.singh@amd.com> <20180904081151.GC32615@zn.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.5 (2018-04-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 10, 2018 at 02:06:57PM -0500, Brijesh Singh wrote: > Nothing prevent user from supplying a bogus number. The main question > is, clamp with what number ? So you definitely want to forbid too large timeouts - that wouldn't make any sense anyway. And too small either, because a too small timeout would make a potentially functioning fw broken. > IMO, if user is overriding the default timeout number then its possible > that user is dealing with a buggy firmware which does not work with > default timeout and silently clamping the value will not help them. No one said "silently" - you simply say: "Correcting PSP "Correcting PSP probe timeout to X seconds." when loading the driver so that the user is aware that the value she entered might not be an optimal one. -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.