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=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED 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 BC9EEC4321D for ; Wed, 15 Aug 2018 19:04:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 58FDC21528 for ; Wed, 15 Aug 2018 19:04:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="GfagmevK" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 58FDC21528 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org 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 S1727457AbeHOV5f (ORCPT ); Wed, 15 Aug 2018 17:57:35 -0400 Received: from mail-io0-f196.google.com ([209.85.223.196]:39606 "EHLO mail-io0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726749AbeHOV5f (ORCPT ); Wed, 15 Aug 2018 17:57:35 -0400 Received: by mail-io0-f196.google.com with SMTP id l7-v6so1854110iok.6 for ; Wed, 15 Aug 2018 12:04:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=1zIBQK5kS4J9YhuEHes31K5V1rpNIQR59/RCacyOg08=; b=GfagmevKUwJnXKfiX4c3VHiczhZ1jYALrMyc5ASHTl71B2znVUPZWrkHrTe/+6wBtz 6opj6QDEM4dbJAh5QIgHxlHIgKYzi8PAKvx1QAimYegUiXwwFLY6Q1vEfLqYEBckuoVT nrXGi40nEAv45KqbC98QIVSKyQFKhuUnXRE6A= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=1zIBQK5kS4J9YhuEHes31K5V1rpNIQR59/RCacyOg08=; b=q6tSlu8JSgz+TIQgRURE5fZfAYrD8mfAHhL/CJdDMfR9YX0AScRxQJuKoRbpDeoOTU TijBmQ/P4GgQanqhh3DtpPr0OonGk+lAwXpGO2PtL1fNm+9y2FnyoQ/NJUC88soz7MSd JGKPmd6PiYrngQue7jw9fN03W9G+kf5PCz7+UpJAdv4WG5lkxjj+8d5rqP4bmWWkgzly S2PaxCKSIYpAEO/E2hCxTXsyiLTtvmIfayRU8lVomi/WwRCWyqMjaRHwepJ0iqGS4/Ul n+P2GchZR8EcFJA8lSKhtqrPglomCRuLCegTM2c6fBH72lTQX+C5x8kxa0/cbFJlJtVV tfuA== X-Gm-Message-State: AOUpUlHNdjJ90u+brMjMIvm1Axai6JvZFA0hCPtGjrJ92c2XN7BFlt98 bCBn06A+JCL7Dcc9Q4jt9X0bVJ8M00hnTR1Sgks= X-Google-Smtp-Source: AA+uWPyTFPax4RXMvGHWZe9rj31TswmV5MtuOQRkJRbNXkwn4OczXDP3gO5WDts391vw6WkZcCJCOdHm/EW+o1/2rP8= X-Received: by 2002:a6b:7a08:: with SMTP id h8-v6mr18963431iom.238.1534359851720; Wed, 15 Aug 2018 12:04:11 -0700 (PDT) MIME-Version: 1.0 References: <20180813214328.GA15137@beast> In-Reply-To: From: Linus Torvalds Date: Wed, 15 Aug 2018 12:04:00 -0700 Message-ID: Subject: Re: [GIT PULL] gcc-plugin updates for v4.19-rc1 To: Kees Cook Cc: Linux Kernel Mailing List , Alexander Popov , Dave Hansen , Ingo Molnar , Masahiro Yamada , Thomas Gleixner , Tycho Andersen , Mark Rutland , Laura Abbott , Will Deacon Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 15, 2018 at 11:35 AM Kees Cook wrote: > > I swear I'm doing my best. Are you speaking of > stackleak_check_alloca() or stackleak_erase()? These were both > discussed on the list, and we weren't able to come up with > alternatives: in both cases we're off the stack, and recovery is > seemingly impossible. Why do you even *test* that thing? Why don't you just allocate stack and clear it. Dammit, the whole f*cking point of this patch-set is to clear the stack used. It is *not* supposed to do anything else. If the process runs out of stack, that's caught by the vmalloc'ed stack. And if you don't have vmalloc'ed stack, then clearly you don't care. I refuse to take this kind of code that does stupid things, and then *because* it does those initial stupid things it does even more stupid things to correct for it. I hated the thing to begin with, told people that there are better approaches that don't have the downsides, got ignored, and then I'm pushed crap. No. Linus