From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932492AbcGZXvy (ORCPT ); Tue, 26 Jul 2016 19:51:54 -0400 Received: from mga09.intel.com ([134.134.136.24]:9349 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932356AbcGZXvo (ORCPT ); Tue, 26 Jul 2016 19:51:44 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.28,427,1464678000"; d="scan'208";a="854147202" Subject: Re: [PATCH] [RFC] Introduce mmap randomization To: Jason Cooper , "Roberts, William C" References: <1469557346-5534-1-git-send-email-william.c.roberts@intel.com> <1469557346-5534-2-git-send-email-william.c.roberts@intel.com> <20160726200309.GJ4541@io.lakedaemon.net> <476DC76E7D1DF2438D32BFADF679FC560125F29C@ORSMSX103.amr.corp.intel.com> <20160726205944.GM4541@io.lakedaemon.net> <476DC76E7D1DF2438D32BFADF679FC5601260068@ORSMSX103.amr.corp.intel.com> <20160726214453.GN4541@io.lakedaemon.net> Cc: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "kernel-hardening@lists.openwall.com" , "akpm@linux-foundation.org" , "keescook@chromium.org" , "gregkh@linuxfoundation.org" , "nnk@google.com" , "jeffv@google.com" , "salyzyn@android.com" , "dcashman@android.com" From: Dave Hansen Message-ID: <5797F78A.2000600@intel.com> Date: Tue, 26 Jul 2016 16:51:38 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.8.0 MIME-Version: 1.0 In-Reply-To: <20160726214453.GN4541@io.lakedaemon.net> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/26/2016 02:44 PM, Jason Cooper wrote: >> > I'd likely need to take a small sample of programs and examine them, >> > especially considering That as gaps are harder to find, it forces the >> > randomization down and randomization can Be directly altered with >> > length on mmap(), versus randomize_addr() which didn't have this >> > restriction but OOM'd do to fragmented easier. > Right, after the Android feedback from Nick, I think you have a lot of > work on your hands. Not just in design, but also in developing convincing > arguments derived from real use cases. Why not just have the feature be disabled on 32-bit by default? All of the Android problems seemed to originate with having a constrained 32-bit address space.