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_INVALID,DKIM_SIGNED, 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 D27F8C43381 for ; Thu, 7 Mar 2019 19:03:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A283F20675 for ; Thu, 7 Mar 2019 19:03:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="YLnKy32p" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726668AbfCGTD0 (ORCPT ); Thu, 7 Mar 2019 14:03:26 -0500 Received: from merlin.infradead.org ([205.233.59.134]:55664 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726286AbfCGTD0 (ORCPT ); Thu, 7 Mar 2019 14:03:26 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.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:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=ZfrfQvfHDXYd3CUHVVspVqjLPuUt9M5N9AH11BPHM8g=; b=YLnKy32poWN/dRGO02MhpChAb nR8jFWadgAYChKIXCrolGuBrLqiANl/4XmucMqb841HTSh9JvEtrRmZsCKVIOLIYK5IoG8u9EL6lU 7mtpEmKTIyoA+GhMmTo935STlgOh6osHmaaGaxAjvlh8cJHB+xvUhWd2AwTqJc22Xy24i30/E721e J35Z8cjLXPOcazcccBLSfpalsr3wWEaUsYiKnoYqid3pqp3xIwJyNLH8yJkOjySCHRXHVtUdCIvJq w1muLR0v0abdGChhbt78zlg3YSjU000HkhUVD3vUvpPi7zw/5H6qXnU0jy/aNOwQOuS28vclrYRdG 1EOW1fjFQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=worktop.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1h1yIV-0000i7-42; Thu, 07 Mar 2019 19:03:15 +0000 Received: by worktop.programming.kicks-ass.net (Postfix, from userid 1000) id 3C5939837F2; Thu, 7 Mar 2019 20:03:13 +0100 (CET) Date: Thu, 7 Mar 2019 20:03:13 +0100 From: Peter Zijlstra To: Linus Torvalds Cc: Thomas Gleixner , Peter Anvin , Julien Thierry , Will Deacon , Andy Lutomirski , Ingo Molnar , Catalin Marinas , James Morse , valentin.schneider@arm.com, Brian Gerst , Josh Poimboeuf , Andrew Lutomirski , Borislav Petkov , Denys Vlasenko , Linux List Kernel Mailing , Dmitry Vyukov , Steven Rostedt Subject: Re: [PATCH 18/20] objtool: Add UACCESS validation Message-ID: <20190307190313.GA4572@worktop.programming.kicks-ass.net> References: <20190307114511.870090179@infradead.org> <20190307115200.697533978@infradead.org> <20190307174135.GJ32477@hirez.programming.kicks-ass.net> <20190307184813.GL32477@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190307184813.GL32477@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 07, 2019 at 07:48:13PM +0100, Peter Zijlstra wrote: > On Thu, Mar 07, 2019 at 09:54:14AM -0800, Linus Torvalds wrote: > > On Thu, Mar 7, 2019 at 9:41 AM Peter Zijlstra wrote: > > > > > > > > What's the call site that made you go "just add __memset() to the list"? > > > > > > __asan_{,un}poinson_stack_memory() > > > kasan_{,un}poison_shadow() > > > __memset() > > > > Ugh. I think I almost just agree with your decision to just let that > > memset go unchecked. > > > > I'm not saying it's right, but it doesn't seem to be a fight worth fighting. > > One think I could do; is add a filter to each function and only allow > __memset from the kasan code, and not from anywhere else. Ah.. how about I feed objtool a text file with all these symbol names; and I have Makefile compose file that from fragments. Then only KASAN builds will have memset whitelisted, and any other build will still flag memset abuse. Now I only have to figure out how to make Makefile do something like that :-)