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[23.128.96.18]) by mx.google.com with ESMTP id m10si12366126edd.152.2022.02.09.04.44.57; Wed, 09 Feb 2022 04:45:23 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=casper.20170209 header.b=VeemKIC6; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231853AbiBIMDz (ORCPT + 99 others); Wed, 9 Feb 2022 07:03:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39202 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231758AbiBIMD2 (ORCPT ); Wed, 9 Feb 2022 07:03:28 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2D2AEC102FCE for ; Wed, 9 Feb 2022 03:45:32 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=9d9s0Zw5jafTlFFfFiZN8ZnxoxV8CYmJnXxLQUjolS8=; b=VeemKIC64TA/ef60FBzSX4esKn ZlW4Hr6fmfOVPavg0TtmyhUibqEDk1X/81muSvem7C4DtOltKejwRHjJmqSmXrjCnnbYkKkqjPytv me10ManmdIr26zOz9gJ/LVgEN/JoTFIIn0jdnUMLdVP8MT6GGDcnRBiQbGNm3nXcqGkgI9M5YDaOl 1IWOKDyp34G7UX2e9UaVC068+UIg5bDwO3l0Wr3EP1PWCzhoqsOtWWCN+ydPWqNaN+SpP0hMlqgQf oVJFugGe59zJyeVPrTwopS3MUncqu7wXmMVzLNBnKxgsj9gakcXrON7IqoPYpgALYvoJRqyDyRCIH wjmacrxg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=worktop.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1nHlPV-007YMo-BX; Wed, 09 Feb 2022 11:45:21 +0000 Received: by worktop.programming.kicks-ass.net (Postfix, from userid 1000) id E52BC9853C7; Wed, 9 Feb 2022 12:45:19 +0100 (CET) Date: Wed, 9 Feb 2022 12:45:19 +0100 From: Peter Zijlstra To: Kees Cook Cc: Josh Poimboeuf , x86@kernel.org, joao@overdrivepizza.com, hjl.tools@gmail.com, andrew.cooper3@citrix.com, linux-kernel@vger.kernel.org, ndesaulniers@google.com, samitolvanen@google.com Subject: Re: [RFC][PATCH 6/6] objtool: Add IBT validation / fixups Message-ID: <20220209114519.GA65516@worktop.programming.kicks-ass.net> References: <20211122170301.764232470@infradead.org> <20211122170805.338489412@infradead.org> <20211124193037.nu7q4pa3sianzqtc@treble> <202202081542.F685EC23@keescook> <20220209114141.GN23216@worktop.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220209114141.GN23216@worktop.programming.kicks-ass.net> X-Spam-Status: No, score=-4.4 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_MED,SPF_HELO_NONE, SPF_NONE,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 09, 2022 at 12:41:41PM +0100, Peter Zijlstra wrote: > On Tue, Feb 08, 2022 at 03:43:27PM -0800, Kees Cook wrote: > > Why have the kernel do that work at every boot when it can be known at > > link time? > > I have patches that write a 4 byte #UD there instead of a nop. That > would make !IBT hardware splat as well when it hits a sealed function > (and in that case actually having those extra ENDBR generated is a > bonus). > > Anyway, I have some newer patches and some hardware, except it's a NUC > and working with those things is a royal pain in the arse since they > don't have serial. I finally did get XHCI debug port working, but > there's no XDBC grub support, so now I managed to boot a dead kernel and > the thing is a brick until I can be arsed to connect a keybaord and > screen to it again :-( > > KVM/qemu has no IBT support merged yet, so I can't use that either. FWIW, those patches live here: git://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git x86/wip.ibt