From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 22 May 2002 01:01:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 22 May 2002 01:01:21 -0400 Received: from ausmtp01.au.ibm.COM ([202.135.136.97]:21688 "EHLO ausmtp01.au.ibm.com") by vger.kernel.org with ESMTP id ; Wed, 22 May 2002 01:01:20 -0400 Date: Wed, 22 May 2002 15:01:14 +1000 From: Rusty Russell To: Andrew Morton Cc: alan@lxorguk.ukuu.org.uk, pavel@suse.cz, linux-kernel@vger.kernel.org, paulus@samba.org Subject: Re: AUDIT: copy_from_user is a deathtrap. Message-Id: <20020522150114.63a45f09.rusty@rustcorp.com.au> In-Reply-To: <3CEAC020.4F63A181@zip.com.au> X-Mailer: Sylpheed version 0.7.4 (GTK+ 1.2.10; powerpc-debian-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 21 May 2002 14:46:08 -0700 Andrew Morton wrote: > Pavel makes a reasonable point that copy_*_user may elect > to copy the data in something other than strictly ascending > user virtual addresses. In which case it's not possible to return > a sane "how much was copied" number. If I understand Paulus correctly, PPC64 could share their optimized memcpy routine (ie. icache win), from which it is really hard to tell how far we got before we faulted. You then do the fixup search on the link register (ie. to find the caller). Rusty. -- there are those who do and those who hang on and you don't see too many doers quoting their contemporaries. -- Larry McVoy