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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 90153ECAAA1 for ; Fri, 28 Oct 2022 12:03:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229893AbiJ1MDt (ORCPT ); Fri, 28 Oct 2022 08:03:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42814 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229522AbiJ1MDr (ORCPT ); Fri, 28 Oct 2022 08:03:47 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 340571D374E for ; Fri, 28 Oct 2022 05:03:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; 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=82n6RBa9XoGODnQnRPQprS3ZGGcq4vGNRDRtnAIQpAo=; b=ZZa9sWqpWD4mk5ewernqXo0tZ7 JDwneWcYgTU6S7HP4Pl8VVQ5/eVw8QH/z23oOG+DR+GY9yk1QbixPhXBUBrSYNbmPHPmGiJKTGVJD 6eL3QKbayrf5zYd+Ws9Z/AZRBLBk8GDJRlLhYwEXOkqzepPEvM1lOrve4EX9PBnBBOPoymGXijBrw HbZFk3rpy1nO7ACSYfh5XFkhlHTJP/M8rYZHN6m1GX7wtcFnlCqAV5DuOFGnVFee0bpr8d9RApo6c dTA/IrSASCXEznfW7esYIIQzR2ACwUx9ONT7e7k4MChmMGe5uLNM5XKoRAk6P1p7ivLHYhU6I9IuN e3UJ4Iiw==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1ooO58-0076Ja-5d; Fri, 28 Oct 2022 12:03:26 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 1528830035C; Fri, 28 Oct 2022 14:03:25 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id E11C52C6CBA2E; Fri, 28 Oct 2022 14:03:24 +0200 (CEST) Date: Fri, 28 Oct 2022 14:03:24 +0200 From: Peter Zijlstra To: David Laight Cc: "x86@kernel.org" , "linux-kernel@vger.kernel.org" , Kees Cook , Sami Tolvanen , Joao Moreira , Josh Poimboeuf , Mark Rutland Subject: Re: [PATCH 0/4] x86/ibt: Implement FineIBT Message-ID: References: <20221027092812.185993858@infradead.org> <322c0b333f0a4a60be2a89f0cdf7edde@AcuMS.aculab.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <322c0b333f0a4a60be2a89f0cdf7edde@AcuMS.aculab.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 28, 2022 at 11:01:08AM +0000, David Laight wrote: > From: Peter Zijlstra > > Sent: 27 October 2022 10:28 > > > > Hi all, > > > > Updated FineIBT series; I've (hopefully) incorporated all feedback from last > > time with the notable exception of the Kconfig CFI default -- I'm not sure we > > want to add to the Kconfig space for this, also what would a distro do with it. > > > > Anyway; please have a look, I'm hoping to merge this soonish so we can make the > > next cycle. > > Is there a test to ensure that modules are actually compiled > with the required endbra, function prologue gap (etc). > Having the module load fail is somewhat better than a crash. > > It is almost certainly quite easy to generate an out of tree module that > is missing all of those (even if compiled at the same time as the kernel). > (Never mind issues with modules that contain binary blobs.) There is not; it is always possible to load a 'malformed' module. We have no sanity checking on modules. It is no different from any other binary compatilibity issue; if you build a dud module, you get to keep the pieces.