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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 97A26C433DF for ; Fri, 26 Jun 2020 20:18:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7290E20720 for ; Fri, 26 Jun 2020 20:18:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="FrkG7xHD" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725957AbgFZUSt (ORCPT ); Fri, 26 Jun 2020 16:18:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40794 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725780AbgFZUSt (ORCPT ); Fri, 26 Jun 2020 16:18:49 -0400 Received: from mail-pf1-x444.google.com (mail-pf1-x444.google.com [IPv6:2607:f8b0:4864:20::444]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5B536C03E979 for ; Fri, 26 Jun 2020 13:18:49 -0700 (PDT) Received: by mail-pf1-x444.google.com with SMTP id f9so5104975pfn.0 for ; Fri, 26 Jun 2020 13:18:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=/DjWbdB6QR6F3h1vBMYs8FI30xxDOIUG4fAHYu8nECU=; b=FrkG7xHDJ0hpKYFzhPGuCwru1szypTYOGi5hD5lbAfuGgT1pRq6kqZRC1RYyGXQ4Cx dBBF0DZ0m//3+/ZhtdALlqhCmQJr+DsmxShR47yHKzFznf60VL/beb/6bYpfKhHVdEyz yh40AuQXBaVxjsQclGj9K/76x2HjcqutOZc2Y= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=/DjWbdB6QR6F3h1vBMYs8FI30xxDOIUG4fAHYu8nECU=; b=paqyWCiuq8pPumeUkvsAnLtHOM6kI373p4z75KUtPNkUTNPRcZukysMPjKiwJHXpX1 oLVuZgNu2BnCxPJ3nKQuyDCbFL1EQ0gR1wVWnI3cuHqlLsMYm6mzHkCdQo1y9wScSXts Q41LFLmjYyBFxQ0HRBcOLbWgYjiF2cubMDGCuBlxFlZrtX6560W+LxwqwJnMz2ByB2ml M5iOdJkdrrFzr4/EJxEPKmiNwDfFZTbtp1I9Ge/rFoo838THt8MDyexvr6WwZ6nMJTYK D/lsGoZZUBt0PaM50U3ovqx33Xbl3LA2wyhdjtslBrQmytdaF3L1rIWyBB1h815CICI1 DNSw== X-Gm-Message-State: AOAM532FOOeA0QuxNdUPHn/MDuHD8W9kepCHZevGQS/StrhT6Qeqvn5A WdjhnKO6Hiuz8Yjzr68GBtyrSw== X-Google-Smtp-Source: ABdhPJwYJkgs+qfqxsrtQQlApXR25CpCAIB9YF/4D3mpyg8KTrXfQyU2bY8skxNl8rMJC5c6opRIug== X-Received: by 2002:a62:1ad6:: with SMTP id a205mr4256254pfa.109.1593202728953; Fri, 26 Jun 2020 13:18:48 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id c141sm11968090pfc.167.2020.06.26.13.18.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 26 Jun 2020 13:18:47 -0700 (PDT) Date: Fri, 26 Jun 2020 13:18:46 -0700 From: Kees Cook To: Masahiro Yamada Cc: Peter Zijlstra , Thomas Gleixner , X86 ML , Linux Kbuild mailing list , linux-arm-kernel , Linux Kernel Mailing List Subject: Re: [PATCH] kbuild: Provide way to actually disable stack protector Message-ID: <202006261314.B6856AA96@keescook> References: <202006221201.3641ED037E@keescook> <202006222234.FBCEAD7F@keescook> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jun 27, 2020 at 04:04:33AM +0900, Masahiro Yamada wrote: > On Tue, Jun 23, 2020 at 2:37 PM Kees Cook wrote: > > > > On Tue, Jun 23, 2020 at 11:33:53AM +0900, Masahiro Yamada wrote: > > > Is it OK to not patch syscall_x32.c ? > > > > Good question. Peter? (It seems all the syscall_*.c files are just a > > table, not code -- why do they need any instrumentation changes?) I'd still like to know the answer to this one... > Is it useful when we know > DISABLE_STACKPROTECTOR = -fno-stack-protector ? I'm fine with that. My point was the using _REMOVE isn't going to work for some compiler builds. > I'd rather want to apply this patch > https://patchwork.kernel.org/patch/11628493/ > and hard-code -fno-stack-protector where necessary. That's fine. I will send a separate fix for arch/x86/entry/Makefile. > cc-flags-y comes after KBUILD_CFLAGS > so that -fno-stack-protector can negate -fstack-protector(-strong) Okay, good. -- Kees Cook