From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Tue, 03 Mar 2015 08:31:45 +0100 (CET) Received: from mail-wg0-f49.google.com ([74.125.82.49]:39416 "EHLO mail-wg0-f49.google.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S27006779AbbCCHbnLz7KS (ORCPT ); Tue, 3 Mar 2015 08:31:43 +0100 Received: by wggx12 with SMTP id x12so38126080wgg.6; Mon, 02 Mar 2015 23:31:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; bh=bEJRDpNTx6PykpJ674CppB7jD48X4TET+E/xYZxVYGk=; b=QEc35ydBVReBF8sEy08+7CCc812bT7D+i6APFUONkY67Qa38Xa+sGZoUw+ETyJW5TT cSSeNcjNFsQuUSeg7JYRzgLE/bOj5lY8qpWKLrB7nSD7Mw/OdiCndWvh6TIj7tBPclA7 mqB5NgGFGsho4OJcSg/GRQbU/Y36bM9h9vFg6IUMHHOi5xb9ICc8HzHYy4uG02UP87qT U97CAN6fq8aEh4u1S0jQ1LYcfNW0C/jF00offc2wx2tsZGbSM6dDAu4RwwPnpp6rY84p 5hv51K6v6ypmxXqrA2LXCtQTH4PyiHUAbPPlu+SwJcaLtY01MX13BbCv5wmEDiDGAkoB ufYw== X-Received: by 10.180.207.6 with SMTP id ls6mr43798834wic.13.1425367898432; Mon, 02 Mar 2015 23:31:38 -0800 (PST) Received: from gmail.com (540334ED.catv.pool.telekom.hu. [84.3.52.237]) by mx.google.com with ESMTPSA id jy7sm19255366wid.22.2015.03.02.23.31.34 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 02 Mar 2015 23:31:36 -0800 (PST) Date: Tue, 3 Mar 2015 08:31:32 +0100 From: Ingo Molnar To: Kees Cook Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, Russell King , Catalin Marinas , Will Deacon , Ralf Baechle , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Martin Schwidefsky , Heiko Carstens , linux390@de.ibm.com, x86@kernel.org, Alexander Viro , Oleg Nesterov , Andy Lutomirski , "David A. Long" , Andrey Ryabinin , Arun Chandran , Yann Droneaud , Min-Hua Chen , Paul Burton , Alex Smith , Markos Chandras , Jeff Bailey , Vineeth Vijayan , Michael Holzheu , Ben Hutchings , Hector Marco-Gisbert , Borislav Petkov , Jan-Simon =?iso-8859-1?Q?M=F6ller?= , linux-arm-kernel@lists.infradead.org, linux-mips@linux-mips.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-fsdevel@vger.kernel.org, Linus Torvalds , Borislav Petkov , "H. Peter Anvin" , Thomas Gleixner Subject: Re: [PATCH v2 0/5] split ET_DYN ASLR from mmap ASLR Message-ID: <20150303073132.GA30602@gmail.com> References: <1425341988-1599-1-git-send-email-keescook@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1425341988-1599-1-git-send-email-keescook@chromium.org> User-Agent: Mutt/1.5.23 (2014-03-12) Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 46093 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: mingo@kernel.org Precedence: bulk List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: linux-mips X-List-ID: linux-mips List-subscribe: List-owner: List-post: List-archive: X-list: linux-mips * Kees Cook wrote: > To address the "offset2lib" ASLR weakness[1], this separates ET_DYN > ASLR from mmap ASLR, as already done on s390. The architectures > that are already randomizing mmap (arm, arm64, mips, powerpc, s390, > and x86), have their various forms of arch_mmap_rnd() made available > via the new CONFIG_ARCH_HAS_ELF_RANDOMIZE. For these architectures, > arch_randomize_brk() is collapsed as well. > > This is an alternative to the solutions in: > https://lkml.org/lkml/2015/2/23/442 Looks good so far: Reviewed-by: Ingo Molnar While reviewing this series I also noticed that the following code could be factored out from architecture mmap code as well: - arch_pick_mmap_layout() uses very similar patterns across the platforms, with only few variations. Many architectures use the same duplicated mmap_is_legacy() helper as well. There's usually just trivial differences between mmap_legacy_base() approaches as well. - arch_mmap_rnd(): the PF_RANDOMIZE checks are needlessly exposed to the arch routine - the arch routine should only concentrate on arch details, not generic flags like PF_RANDOMIZE. In theory the mmap layout could be fully parametrized as well: i.e. no callback functions to architectures by default at all: just declarations of bits of randomization desired (or, available address space bits), and perhaps an arch helper to allow 32-bit vs. 64-bit address space distinctions. 'Weird' architectures could provide special routines, but only by overriding the default behavior, which should be generic, safe and robust. Thanks, Ingo