From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932297AbVIJSGg (ORCPT ); Sat, 10 Sep 2005 14:06:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932255AbVIJSEn (ORCPT ); Sat, 10 Sep 2005 14:04:43 -0400 Received: from ppp-62-11-72-160.dialup.tiscali.it ([62.11.72.160]:33960 "EHLO zion.home.lan") by vger.kernel.org with ESMTP id S932251AbVIJSEg (ORCPT ); Sat, 10 Sep 2005 14:04:36 -0400 Message-Id: <20050910174629.286344000@zion.home.lan> References: <20050910174452.907256000@zion.home.lan> Date: Sat, 10 Sep 2005 19:44:57 +0200 From: "Paolo 'Blaisorblade' Giarrusso" To: Linus Torvalds Cc: Jeff Dike , Paolo Blaisorblade Giarrusso Cc: LKML Cc: user-mode-linux-devel@lists.sourceforge.net Subject: [patch 5/7] uml: fix fault handler on write Content-Disposition: inline; filename=uml-fix-fault-handler-on-write Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org The UML fault handler was recently changed to enforce PROT_NONE protections, by requiring VM_READ or VM_EXEC on VMA's. However, by mistake, things were changed such that VM_READ is always checked, also on write faults; so a VMA mapped with only PROT_WRITE is not readable (unless it's prefaulted with MAP_POPULATE or with a write), which is different from i386. Discovered while testing remap_file_pages protection support. Signed-off-by: Paolo 'Blaisorblade' Giarrusso --- arch/um/kernel/trap_kern.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) diff --git a/arch/um/kernel/trap_kern.c b/arch/um/kernel/trap_kern.c --- a/arch/um/kernel/trap_kern.c +++ b/arch/um/kernel/trap_kern.c @@ -57,7 +57,8 @@ good_area: if(is_write && !(vma->vm_flags & VM_WRITE)) goto out; - if(!(vma->vm_flags & (VM_READ | VM_EXEC))) + /* Don't require VM_READ|VM_EXEC for write faults! */ + if(!is_write && !(vma->vm_flags & (VM_READ | VM_EXEC))) goto out; do { --