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=DKIMWL_WL_HIGH,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 7E9DFC3F2CD for ; Mon, 2 Mar 2020 18:39:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5260324676 for ; Mon, 2 Mar 2020 18:39:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="nPCbvNh1" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727502AbgCBSjt (ORCPT ); Mon, 2 Mar 2020 13:39:49 -0500 Received: from mail-pl1-f193.google.com ([209.85.214.193]:35179 "EHLO mail-pl1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727316AbgCBSjs (ORCPT ); Mon, 2 Mar 2020 13:39:48 -0500 Received: by mail-pl1-f193.google.com with SMTP id g6so135871plt.2 for ; Mon, 02 Mar 2020 10:39:46 -0800 (PST) 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=70PNbjd99jhwaP11CwZH+hyBf72TvQn+KUnto1xAKv4=; b=nPCbvNh1ZilYd3+c9woWZLKCkHDNCMs4zM19THJWS1JFKGZS96fPY5ZHZQVhjdwA/V xkhGNK7E20uN7WXEdgQdFyA8sPfOalP+Y56a92YVtd7GAymf7tlJPoH5d4/VtkocXtZC gDAY3h+7nlI1LyUT3vxrGFUIcVy9miP0sEtJw= 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=70PNbjd99jhwaP11CwZH+hyBf72TvQn+KUnto1xAKv4=; b=JIdhmOVpKrnrs50DgGM8RjmjYa9V4rxa8mAKOC3Fr6/B3obDm+TLgX3mxh1/hv1Vf5 4ENAlBNJU/2kfzzeKm9y2LMzTRWJQPkrkP3oQOXeQvMN3ZZQE0mrmo/i5aOcPUdt4pr8 rp0ss/Nfwir9bKeZOc3JxhSO59aag+zy7vkUXywKsXQmJCv29DE55b7CnctSvWbH4QsY hyI5p/rAOYoR2AuxQTzJBRDfIFoLfM9ObmA8aI+daH3r7ApkAqjX7hkcsYKSojS3IpZX ZITAzPOrmx3FylQKAg8220JHBebL7Mm3IK8PGXwDAvgWuU6rHyzkAfzR7+eTdONP8oBt ki1g== X-Gm-Message-State: ANhLgQ0FV+mVnTifEcEolKJQr2/7zxpKtV5OeeJzJSjHFllkKVXiQ2k5 sg+8wI3wX3tRtTE5Lw9BPnph1Q== X-Google-Smtp-Source: ADFU+vuzu2VB845Es4ZS28fsp07dY6EVS7FKBRbOSgalZGRvsU+H2Z/auP14eke/ZoTPHViBUPqJTg== X-Received: by 2002:a17:902:8d89:: with SMTP id v9mr495019plo.83.1583174386378; Mon, 02 Mar 2020 10:39:46 -0800 (PST) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id l25sm21778354pgn.47.2020.03.02.10.39.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 02 Mar 2020 10:39:45 -0800 (PST) Date: Mon, 2 Mar 2020 10:39:44 -0800 From: Kees Cook To: Arvind Sankar Cc: "Tobin C . Harding" , Tycho Andersen , kernel-hardening@lists.openwall.com, Dave Hansen , Andy Lutomirski , Peter Zijlstra , x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] x86/mm/init_32: Stop printing the virtual memory layout Message-ID: <202003021039.257258E1B@keescook> References: <202002291534.ED372CC@keescook> <20200301002209.1304982-1-nivedita@alum.mit.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200301002209.1304982-1-nivedita@alum.mit.edu> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Feb 29, 2020 at 07:22:09PM -0500, Arvind Sankar wrote: > For security, don't display the kernel's virtual memory layout. > > Signed-off-by: Arvind Sankar If this needs a v3, I'd just list the commits I mentioned for further justification. But regardless: Acked-by: Kees Cook -Kees > --- > arch/x86/mm/init_32.c | 38 -------------------------------------- > 1 file changed, 38 deletions(-) > > diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c > index 23df4885bbed..8ae0272c1c51 100644 > --- a/arch/x86/mm/init_32.c > +++ b/arch/x86/mm/init_32.c > @@ -788,44 +788,6 @@ void __init mem_init(void) > x86_init.hyper.init_after_bootmem(); > > mem_init_print_info(NULL); > - printk(KERN_INFO "virtual kernel memory layout:\n" > - " fixmap : 0x%08lx - 0x%08lx (%4ld kB)\n" > - " cpu_entry : 0x%08lx - 0x%08lx (%4ld kB)\n" > -#ifdef CONFIG_HIGHMEM > - " pkmap : 0x%08lx - 0x%08lx (%4ld kB)\n" > -#endif > - " vmalloc : 0x%08lx - 0x%08lx (%4ld MB)\n" > - " lowmem : 0x%08lx - 0x%08lx (%4ld MB)\n" > - " .init : 0x%08lx - 0x%08lx (%4ld kB)\n" > - " .data : 0x%08lx - 0x%08lx (%4ld kB)\n" > - " .text : 0x%08lx - 0x%08lx (%4ld kB)\n", > - FIXADDR_START, FIXADDR_TOP, > - (FIXADDR_TOP - FIXADDR_START) >> 10, > - > - CPU_ENTRY_AREA_BASE, > - CPU_ENTRY_AREA_BASE + CPU_ENTRY_AREA_MAP_SIZE, > - CPU_ENTRY_AREA_MAP_SIZE >> 10, > - > -#ifdef CONFIG_HIGHMEM > - PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE, > - (LAST_PKMAP*PAGE_SIZE) >> 10, > -#endif > - > - VMALLOC_START, VMALLOC_END, > - (VMALLOC_END - VMALLOC_START) >> 20, > - > - (unsigned long)__va(0), (unsigned long)high_memory, > - ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20, > - > - (unsigned long)&__init_begin, (unsigned long)&__init_end, > - ((unsigned long)&__init_end - > - (unsigned long)&__init_begin) >> 10, > - > - (unsigned long)&_etext, (unsigned long)&_edata, > - ((unsigned long)&_edata - (unsigned long)&_etext) >> 10, > - > - (unsigned long)&_text, (unsigned long)&_etext, > - ((unsigned long)&_etext - (unsigned long)&_text) >> 10); > > /* > * Check boundaries twice: Some fundamental inconsistencies can > -- > 2.24.1 > -- Kees Cook