Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932327AbWHGW4x (ORCPT ); Mon, 7 Aug 2006 18:56:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751164AbWHGW4r (ORCPT ); Mon, 7 Aug 2006 18:56:47 -0400 Received: from nevyn.them.org ([66.93.172.17]:55255 "EHLO nevyn.them.org") by vger.kernel.org with ESMTP id S1750952AbWHGW4n (ORCPT ); Mon, 7 Aug 2006 18:56:43 -0400 Date: Mon, 7 Aug 2006 18:56:42 -0400 From: Daniel Jacobowitz To: David Wagner Cc: linux-kernel@vger.kernel.org Subject: Re: [RFC/PATCH] revoke/frevoke system calls V2 Message-ID: <20060807225642.GA31752@nevyn.them.org> Mail-Followup-To: David Wagner , linux-kernel@vger.kernel.org References: <20060807101745.61f21826.froese@gmx.de> <84144f020608070251j2e14e909v8a18f62db85ff3d4@mail.gmail.com> <20060807224144.3bb64ac4.froese@gmx.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.11+cvs20060403 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1020 Lines: 22 On Mon, Aug 07, 2006 at 10:52:59PM +0000, David Wagner wrote: > I'm still trying to understand the semantics of this proposed > frevoke() implementation. Can an attacker use this to forcibly > close some other processes' file descriptor? Suppose the target > process has fd 0 open and the attacker revokes the file corresponding > to fd 0; what is the state of fd 0 in the target process? Is it > closed? If the target process then open()s another file, does it > get bound to fd 0? (Recall that open() always binds to the lowest > unused fd.) If the answers are "yes", then the security consequences > seem very scary. No, that's already been answered at least once. The file remains open, but returns EBADF on various operations. -- Daniel Jacobowitz CodeSourcery - 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/