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=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 8027FC54FD0 for ; Mon, 27 Apr 2020 08:47:59 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 42F2A206D4 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" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 42F2A206D4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=sifive.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id D50058E0005; Mon, 27 Apr 2020 04:47:58 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D00E68E0001; Mon, 27 Apr 2020 04:47:58 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C16A88E0005; Mon, 27 Apr 2020 04:47:58 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0158.hostedemail.com [216.40.44.158]) by kanga.kvack.org (Postfix) with ESMTP id AA6C88E0001 for ; Mon, 27 Apr 2020 04:47:58 -0400 (EDT) Received: from smtpin16.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 5A74B824934B for ; Mon, 27 Apr 2020 08:47:58 +0000 (UTC) X-FDA: 76753007436.16.pets24_28759ddaf3204 X-HE-Tag: pets24_28759ddaf3204 X-Filterd-Recvd-Size: 4757 Received: from mail-ot1-f66.google.com (mail-ot1-f66.google.com [209.85.210.66]) by imf21.hostedemail.com (Postfix) with ESMTP for ; Mon, 27 Apr 2020 08:47:57 +0000 (UTC) Received: by mail-ot1-f66.google.com with SMTP id m13so24838932otf.6 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=NI5NCCU+M90UXKQwPzkmjwPgPuQgYjS3d4ZaRP7Y2D1+e+bkoHrFsnTsiTP+pli9wk ckPCoyCznctQNhHS0FTCX9T1d+dvtlHmWoaqgH+0jKK+JFe2x4bhvIdtGqe1ttpGUOfX MgzRG++lPvUNNwu8TKH2Eg3HxvHDYjZhUXDWbl6md9nvjADisQzbgALnqZNaWpGZeS5q gvKWZrNUku3mU+YfaU7Bj84tNmcZpS5ZimuSUwToL1QjOYeE+z1MpZMEzd4IKEWwvgr+ TgtxceHSyJ/PiFCkqKuXQ4X0cRErDkbXNAusx48ODsru58D2pYogdyeFtCHPFToTjKhF RRGw== X-Gm-Message-State: AGi0PuZFbkCKUWelcUkXM/ANmGEkTKW4e20jksJIi9gqQWuaFNc2QtTl 8MBzWNqjHCSsULH0aPi2bbheeYA1z/LoaVwnl7qo6A== 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" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000007, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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