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=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_NEOMUTT 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 0A620C67863 for ; Thu, 18 Oct 2018 21:24:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ACB2020658 for ; Thu, 18 Oct 2018 21:24:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ACB2020658 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linutronix.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 S1726534AbeJSF1W convert rfc822-to-8bit (ORCPT ); Fri, 19 Oct 2018 01:27:22 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:36049 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725735AbeJSF1V (ORCPT ); Fri, 19 Oct 2018 01:27:21 -0400 Received: from bigeasy by Galois.linutronix.de with local (Exim 4.80) (envelope-from ) id 1gDFmH-0004YE-AJ; Thu, 18 Oct 2018 23:24:21 +0200 Date: Thu, 18 Oct 2018 23:24:21 +0200 From: Sebastian Andrzej Siewior To: Dave Hansen Cc: Andy Lutomirski , Andrew Lutomirski , LKML , X86 ML , Paolo Bonzini , Radim Krcmar , kvm list , "Jason A. Donenfeld" , Rik van Riel Subject: Re: [PATCH 05/11] x86/fpu: set PKRU state for kernel threads Message-ID: <20181018212421.ndjtawc34cqdycyy@linutronix.de> References: <20181004140547.13014-1-bigeasy@linutronix.de> <20181004140547.13014-6-bigeasy@linutronix.de> <39e0a55f-4920-cfde-9bef-09c51109d211@linux.intel.com> <20181018162644.qqjkzoqn2fleyi2b@linutronix.de> <20181018182538.vgotfpsdy7qxl2tg@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8BIT In-Reply-To: User-Agent: NeoMutt/20180716 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018-10-18 13:56:24 [-0700], Dave Hansen wrote: > > But this is not the only loophole: There is ptrace interface which is > > used by gdb (just checked) and also bypasses PKRU. So… > > Bypassing protection keys is not a big deal IMNHO. In places where a > sane one is not readily available, I'm totally fine with just > effectively disabling it (PKRU=0) for the length of time it isn't available. Okay, this makes things easier. Let document that for kernel threads we use PKRU=0. This should be happening in my try right now. I double check tomorrow just in case… Sebastian