Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031160AbWI0Wel (ORCPT ); Wed, 27 Sep 2006 18:34:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1031161AbWI0Wel (ORCPT ); Wed, 27 Sep 2006 18:34:41 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:63132 "EHLO pentafluge.infradead.org") by vger.kernel.org with ESMTP id S1031160AbWI0Wej (ORCPT ); Wed, 27 Sep 2006 18:34:39 -0400 Subject: Re: [patch] remove MNT_NOEXEC check for PROT_EXEC mmaps From: Arjan van de Ven To: Stas Sergeev Cc: Linux kernel , Alan Cox , Hugh Dickins , Ulrich Drepper , Valdis.Kletnieks@vt.edu In-Reply-To: <45198395.4050008@aknet.ru> References: <45150CD7.4010708@aknet.ru> <451555CB.5010006@aknet.ru> <1159037913.24572.62.camel@localhost.localdomain> <45162BE5.2020100@aknet.ru> <1159106032.11049.12.camel@localhost.localdomain> <45169C0C.5010001@aknet.ru> <4516A8E3.4020100@redhat.com> <4516B2C8.4050202@aknet.ru> <4516B721.5070801@redhat.com> <45198395.4050008@aknet.ru> Content-Type: text/plain Organization: Intel International BV Date: Thu, 28 Sep 2006 00:33:50 +0200 Message-Id: <1159396436.3086.51.camel@laptopd505.fenrus.org> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 (2.2.3-2.fc4) Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1122 Lines: 29 On Tue, 2006-09-26 at 23:46 +0400, Stas Sergeev wrote: > Hi Guys. > > Noone provided a reason for (or even tried to defend) > the fact that PROT_EXEC is rejected by "noexec" even > for MAP_PRIVATE, while, say, PROT_WRITE is *not* rejected > for "ro" filesystem for MAP_PRIVATE. What was argued is > only MAP_SHARED. is it? > - The programs (like AFAIK wine) use MAP_PRIVATE mmaps to > access the windows dlls, which are usually on a "noexec" > fat or ntfs partitions. Wine might be smart enough not to > break but fallback to read(), but this is slower and more > memory-consuming. Some other program may not be that smart > and break. So there is clearly a need for MAP_PRIVATE with > PROT_EXEC on the noexec partitions. but really again you are degrading what noexec means. It now starts to mean "only don't execute a little bit" rather than "deny execute requests".... - 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/