Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932365AbWJDEVo (ORCPT ); Wed, 4 Oct 2006 00:21:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932368AbWJDEVo (ORCPT ); Wed, 4 Oct 2006 00:21:44 -0400 Received: from taverner.CS.Berkeley.EDU ([128.32.168.222]:37022 "EHLO taverner.cs.berkeley.edu") by vger.kernel.org with ESMTP id S932365AbWJDEVn (ORCPT ); Wed, 4 Oct 2006 00:21:43 -0400 To: linux-kernel@vger.kernel.org Path: not-for-mail From: daw@cs.berkeley.edu (David Wagner) Newsgroups: isaac.lists.linux-kernel Subject: Re: [patch] remove MNT_NOEXEC check for PROT_EXEC mmaps Date: Wed, 4 Oct 2006 04:21:27 +0000 (UTC) Organization: University of California, Berkeley Message-ID: References: <45150CD7.4010708@aknet.ru> <4522B7CD.4040206@redhat.com> Reply-To: daw-usenet@taverner.cs.berkeley.edu (David Wagner) NNTP-Posting-Host: taverner.cs.berkeley.edu X-Trace: taverner.cs.berkeley.edu 1159935687 5190 128.32.168.222 (4 Oct 2006 04:21:27 GMT) X-Complaints-To: news@taverner.cs.berkeley.edu NNTP-Posting-Date: Wed, 4 Oct 2006 04:21:27 +0000 (UTC) X-Newsreader: trn 4.0-test76 (Apr 2, 2001) Originator: daw@taverner.cs.berkeley.edu (David Wagner) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1325 Lines: 22 Ulrich Drepper wrote: >On 10/3/06, David Wagner wrote: >> Are you familiar with the mmap(PROT_EXEC, MAP_ANONYMOUS) loophole? > >Another person who doesn't know about SELinux. Read > >http://people.redhat.com/drepper/selinux-mem.html You're right, I didn't know about that one. Thanks for the education and for taking the time to respond. I wonder whether it is feasible to run with allow_exec{heap,mem,mod,stack} all set to false, on a real system. Is there any example of a fully worked out SELinux policy that has these set to false? FC5 has allow_execheap set to false and all others set to true in its default SELinux policy, so it looks like the mmap(PROT_EXEC, MAP_ANONYMOUS) loophole remains open in FC5 by default. My concern would be that setting all of the exec-related booleans to false might break so much code that setting them all to false wouldn't be feasible in practice. If so, the theoretical possibility to close the mmap(PROT_EXEC, MAP_ANONYMOUS) loophole may be one of these things that is possible in theory but not in practice. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/