Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750970AbWJHJJB (ORCPT ); Sun, 8 Oct 2006 05:09:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750971AbWJHJJB (ORCPT ); Sun, 8 Oct 2006 05:09:01 -0400 Received: from mail.aknet.ru ([82.179.72.26]:28686 "EHLO mail.aknet.ru") by vger.kernel.org with ESMTP id S1750968AbWJHJJA (ORCPT ); Sun, 8 Oct 2006 05:09:00 -0400 Message-ID: <4528C0B0.4070002@aknet.ru> Date: Sun, 08 Oct 2006 13:11:12 +0400 From: Stas Sergeev User-Agent: Thunderbird 1.5.0.7 (X11/20060913) MIME-Version: 1.0 To: Arjan van de Ven Cc: Ulrich Drepper , Alan Cox , Jakub Jelinek , Linux kernel , Hugh Dickins , Jeremy Fitzhardinge Subject: Re: [patch] honour MNT_NOEXEC for access() References: <4516B721.5070801@redhat.com> <45198395.4050008@aknet.ru> <1159396436.3086.51.camel@laptopd505.fenrus.org> <451E3C0C.10105@aknet.ru> <1159887682.2891.537.camel@laptopd505.fenrus.org> <45229A99.6060703@aknet.ru> <1159899820.2891.542.camel@laptopd505.fenrus.org> <4522AEA1.5060304@aknet.ru> <1159900934.2891.548.camel@laptopd505.fenrus.org> <4522B4F9.8000301@aknet.ru> <20061003210037.GO20982@devserv.devel.redhat.com> <45240640.4070104@aknet.ru> <45269BEE.7050008@aknet.ru> <1160170464.12835.4.camel@localhost.localdomain> <4526C7F4.6090706@redhat.com> <45278D2A.4020605@aknet.ru> <4527D64A.7060002@redhat.com> <4527FC8B.8010208@aknet.ru> <1160296364.3000.167.camel@laptopd505.fenrus.org> In-Reply-To: <1160296364.3000.167.camel@laptopd505.fenrus.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1145 Lines: 28 Hello. Arjan van de Ven wrote: >> but ld.so seems to be >> the special case - it is a kernel helper after all, > in what way is ld.so special in ANY way? It is a kernel helper. Kernel does all the security checks before invoking it. However, when invoked directly, it have to do these checks itself. So it is special in a way that it have to do the security checks which otherwise only the kernel should do. Otherwise, please tell me, how can you solve the problem of ld.so started directly, can execute the files you do not have an exec permission for? The MNT_NOEXEC hack of mmap doesn't solve that. Jeremy proposed playing with flags - interesting. What if the MAP_EXECUTABLE flag, which is currently unused, will be used for the program to explicitly specify that it needs an exec permission on the file, and fail otherwise? Then ld.so can just use that to solve all those permission problems. - 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/