From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sun, 19 May 2002 13:53:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sun, 19 May 2002 13:53:09 -0400 Received: from dell-paw-3.cambridge.redhat.com ([195.224.55.237]:31227 "EHLO passion.cambridge.redhat.com") by vger.kernel.org with ESMTP id ; Sun, 19 May 2002 13:53:09 -0400 X-Mailer: exmh version 2.4 06/23/2000 with nmh-1.0.4 From: David Woodhouse X-Accept-Language: en_GB In-Reply-To: To: Alan Cox Cc: rui.sousa@laposte.net (Rui Sousa), rusty@rustcorp.com.au (Rusty Russell), linux-kernel@vger.kernel.org, kernel-janitor-discuss@lists.sourceforge.net Subject: Re: AUDIT of 2.5.15 copy_to/from_user Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Sun, 19 May 2002 18:52:36 +0100 Message-ID: <12687.1021830756@redhat.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org alan@lxorguk.ukuu.org.uk said: > > On the emu10k1 driver we use access_ok(VERIFY_READ) once at the > > beginning of the write() routine to check we can access the user buffer. > > After that we always use __copy_from_user() and we trust it not to fail. > > Is this correct, or not? > This is correct Even if another thread unmaps the page we were trying to read from between the access_ok() and the actual copy? -- dwmw2