Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 27 Jul 2001 05:46:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 27 Jul 2001 05:46:40 -0400 Received: from router-100M.swansea.linux.org.uk ([194.168.151.17]:57605 "EHLO the-village.bc.nu") by vger.kernel.org with ESMTP id ; Fri, 27 Jul 2001 05:46:25 -0400 Subject: Re: Validating Pointers To: tpepper@vato.org Date: Fri, 27 Jul 2001 10:47:16 +0100 (BST) Cc: alan@lxorguk.ukuu.org.uk (Alan Cox), linux-kernel@vger.kernel.org In-Reply-To: <20010726201909.A19877@cb.vato.org> from "tpepper@vato.org" at Jul 26, 2001 08:19:09 PM X-Mailer: ELM [version 2.5 PL5] MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-Id: From: Alan Cox Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Original-Recipient: rfc822;linux-kernel-outgoing > copy_to_user(user_addr, kernel_addr, size); > and > copy_from_user(kernel_addr, user_addr, size); > > Are you saying that static and dynamically allocated kernel variables end up > in different segments (kernel_ds and user_ds) and the copy is only expected to > succeed if the to and from addresses are in the same segment? user and kernel address spaces are seperate. On S/390 and M68K for example they occupy the same values for both. Long long ago this was done via segments on x86 (we dont use segments now) and thus the functions to do what you want are still called set_fs/get_fs/get_ds - 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/