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=-6.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 89BE6C55199 for ; Mon, 27 Apr 2020 08:47:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 561702098B for ; Mon, 27 Apr 2020 08:47:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=sifive.com header.i=@sifive.com header.b="aJaVtmhn" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726611AbgD0Ir6 (ORCPT ); Mon, 27 Apr 2020 04:47:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37234 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725899AbgD0Ir6 (ORCPT ); Mon, 27 Apr 2020 04:47:58 -0400 Received: from mail-ot1-x344.google.com (mail-ot1-x344.google.com [IPv6:2607:f8b0:4864:20::344]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E583EC061A0F for ; Mon, 27 Apr 2020 01:47:57 -0700 (PDT) Received: by mail-ot1-x344.google.com with SMTP id z25so24820009otq.13 for ; Mon, 27 Apr 2020 01:47:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sifive.com; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=mlWbhU9/EmkPkE3KgFalNDlgj8IuZTC+N04d/sX94zU=; b=aJaVtmhnB60iCS5aU72qYpjSl4GarLyMRo6mE3SWoVddygx/s1bcaKs3gTE7K6UUbO o4RayG4kLMsthZ9NAP40ehfOAxyhj1LEfHG6eB/gKUS0vVj/9mXcBIpIkUzUKNi3NCri hHRRvTjFPtdMy6vHuqYxugy7S7L4Le7YTPCBV3O/K1uZVjb6eeVVAy9m9PSWczUpLWJI OQ0ci1aMz8766LfwSXYkTxDlOXnE+Sp7uR/aCOClWA2dJTGvai4EeTwjlFCYCtpdtzm8 fyrwDqx8JizdfM4qescTEoft91MXwbAOE8Jn49/tyDCfNvjsXpUyPgTfuA80krsiVVb/ 7qew== 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=mlWbhU9/EmkPkE3KgFalNDlgj8IuZTC+N04d/sX94zU=; b=e1CADfzOk4Dv2xmiIwv1GYe/XFphRSD2cbR7Iyum+hzKOzCFcydRK9iHY+PCv+8+nV wetXP0UvpmdVkEMBLdHWhRNWy1QfHgxD0OhJo8eRwpoRMOYza4W0LRb1uCZZIerah8mu dcGfSIPrNm8oSOuUnAIBwM6RsL7S4/Xwsd4I/uUok7ks5ZyIvKIZ+m4XnZSGuj1nZ5/i 7aejI0FLm3T63QGyGrjO1f/DQO2MBRiDK4dPngUPHU6ZQIWT/3SJI3UWrfhNJBy3c8l9 dXqDlKoTNhsP09yfpdkwhfNf8TlN5oh+z0RCk/j+b1c8cNqN6f5x7Jjw4pXF2kTDXWOs 8sJg== X-Gm-Message-State: AGi0PuYh5pzZzvLT5SzxSYRsHqjKDbB6Txhs0V562fTBzvGd018kkN7t BsvgPlEtacIzW9S78SUlLMIDb/7EUFE9Bc9vFvxkAg== X-Google-Smtp-Source: APiQypLF9Liz1Wy9Drrlg62h9adl1IQdvPHEtoI3csNtrhxw2UwXHBiWwoYfsvKYHOmr9NvTZRbKN9FmhAyxIBwBF3g= X-Received: by 2002:aca:c78d:: with SMTP id x135mr351307oif.91.1587977277220; Mon, 27 Apr 2020 01:47:57 -0700 (PDT) MIME-Version: 1.0 References: <23980cd0f0e5d79e24a92169116407c75bcc650d.1587455584.git.zong.li@sifive.com> <20200427074915.GA11787@willie-the-truck> In-Reply-To: <20200427074915.GA11787@willie-the-truck> From: Zong Li Date: Mon, 27 Apr 2020 16:47:47 +0800 Message-ID: Subject: Re: [PATCH 1/4] mm: add DEBUG_WX support To: Will Deacon Cc: akpm@linux-foundation.org, linux-mm@kvack.org, "linux-kernel@vger.kernel.org List" , Paul Walmsley , Palmer Dabbelt , linux-riscv , tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, catalin.marinas@arm.com, linux-arm-kernel 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 Mon, Apr 27, 2020 at 3:49 PM Will Deacon wrote: > > On Tue, Apr 21, 2020 at 04:17:12PM +0800, Zong Li wrote: > > Some architectures support DEBUG_WX function, it's verbatim from each > > others. Extract to mm/Kconfig.debug for shared use. > > > > Signed-off-by: Zong Li > > Suggested-by: Palmer Dabbelt > > --- > > mm/Kconfig.debug | 33 +++++++++++++++++++++++++++++++++ > > 1 file changed, 33 insertions(+) > > > > diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug > > index 0271b22e063f..077458ad968d 100644 > > --- a/mm/Kconfig.debug > > +++ b/mm/Kconfig.debug > > @@ -118,6 +118,39 @@ config DEBUG_RODATA_TEST > > ---help--- > > This option enables a testcase for the setting rodata read-only. > > > > +config ARCH_HAS_DEBUG_WX > > + bool > > + > > +config DEBUG_WX > > + bool "Warn on W+X mappings at boot" > > + depends on ARCH_HAS_DEBUG_WX > > + select PTDUMP_CORE > > + help > > + Generate a warning if any W+X mappings are found at boot. > > + > > + This is useful for discovering cases where the kernel is leaving > > + W+X mappings after applying NX, as such mappings are a security risk. > > + This check also includes UXN, which should be set on all kernel > > + mappings. > > "UXN" is the name of a bit in the arm64 page-table descriptors, so this > should be reworded now that it's in generic help text. > It's exactly. Sorry for missing the statement. Hi Andrew, Shall I send a next version patch to fix it? It should be "This is useful for discovering cases where the kernel is leaving W+X mappings after applying NX, as such mappings are a security risk." here. > Will