From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753646AbbI1WUW (ORCPT ); Mon, 28 Sep 2015 18:20:22 -0400 Received: from terminus.zytor.com ([198.137.202.10]:58807 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752989AbbI1WUU (ORCPT ); Mon, 28 Sep 2015 18:20:20 -0400 User-Agent: K-9 Mail for Android In-Reply-To: References: <56045BC4.7000604@tycho.nsa.gov> <56045C8A.50102@tycho.nsa.gov> <20150925072259.GA17639@gmail.com> <5609AE16.2070204@zytor.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Subject: Re: rwx mapping between ex_table and rodata From: "H. Peter Anvin" Date: Mon, 28 Sep 2015 15:20:11 -0700 To: Kees Cook CC: Ingo Molnar , Stephen Smalley , "x86@kernel.org" , lkml Message-ID: <6DF76AF6-E1A6-4C3B-9506-2B842F183B6F@zytor.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Need to fix. Not sure where the rwx mapping comes from. On September 28, 2015 3:05:33 PM PDT, Kees Cook wrote: >On Mon, Sep 28, 2015 at 2:16 PM, H. Peter Anvin wrote: >> On 09/25/2015 12:22 AM, Ingo Molnar wrote: >>>> >>>> To me it looks like another alignment/padding issue like got fixed >>>> before. The space between __ex_table and rodata is (seems?) unused, >so >>>> the default page table permissions end up being W+X. Can we fix the >>>> default to be NX instead? It'll make these bugs stay gone. >>> >>> Yeah. Wanna send a patch for that? >>> >> >> At least in the high mapping space, the default should be no >permissions >> (not present), rather than just NX. > >Do you mean "should be" as in, that's how it's coded now, or "should >be" in that we need to fix it? (If we need to fix it, where is that >"default"? I haven't been able to find it yet.) > >-Kees -- Sent from my Android device with K-9 Mail. Please excuse my brevity.