Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1946717AbWKAJS2 (ORCPT ); Wed, 1 Nov 2006 04:18:28 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1946718AbWKAJS2 (ORCPT ); Wed, 1 Nov 2006 04:18:28 -0500 Received: from cantor.suse.de ([195.135.220.2]:61108 "EHLO mx1.suse.de") by vger.kernel.org with ESMTP id S1946717AbWKAJS1 (ORCPT ); Wed, 1 Nov 2006 04:18:27 -0500 Date: Wed, 1 Nov 2006 10:18:22 +0100 From: Karsten Keil To: Willy Tarreau Cc: Chris Wright , linux-kernel@vger.kernel.org, Jeff Garzik Subject: Re: [PATCH 49/61] ISDN: fix drivers, by handling errors thrown by ->readstat() Message-ID: <20061101091822.GA15633@pingi.kke.suse.de> Mail-Followup-To: Willy Tarreau , Chris Wright , linux-kernel@vger.kernel.org, Jeff Garzik References: <20061101053340.305569000@sous-sol.org> <20061101054422.145185000@sous-sol.org> <20061101074922.GE543@1wt.eu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20061101074922.GE543@1wt.eu> Organization: SuSE Linux AG X-Operating-System: Linux 2.6.16.21-0.23-smp x86_64 User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2545 Lines: 66 On Wed, Nov 01, 2006 at 08:49:22AM +0100, Willy Tarreau wrote: > On Tue, Oct 31, 2006 at 09:34:29PM -0800, Chris Wright wrote: > > -stable review patch. If anyone has any objections, please let us know. > > ------------------ > > > > From: Jeff Garzik > > > > This is a particularly ugly on-failure bug, possibly security, since the > > lack of error handling here is covering up another class of bug: failure to > > handle copy_to_user() return values. > > > > The I4L API function ->readstat() returns an integer, and by looking at > > several existing driver implementations, it is clear that a negative return > > value was meant to indicate an error. > > > > Given that several drivers already return a negative value indicating an > > errno-style error, the current code would blindly accept that [negative] > > value as a valid amount of bytes read. Obvious damage ensues. > > > > Correcting ->readstat() handling to properly notice errors fixes the > > existing code to work correctly on error, and enables future patches to > > more easily indicate errors during operation. > > > > Signed-off-by: Jeff Garzik > > Cc: Karsten Keil > > Cc: > > Signed-off-by: Andrew Morton > > Signed-off-by: Linus Torvalds > > Signed-off-by: Chris Wright > > --- > > drivers/isdn/i4l/isdn_common.c | 9 ++++++--- > > 1 file changed, 6 insertions(+), 3 deletions(-) > > > > --- linux-2.6.18.1.orig/drivers/isdn/i4l/isdn_common.c > > +++ linux-2.6.18.1/drivers/isdn/i4l/isdn_common.c > > @@ -1134,9 +1134,12 @@ isdn_read(struct file *file, char __user > > if (dev->drv[drvidx]->interface->readstat) { > > if (count > dev->drv[drvidx]->stavail) > > count = dev->drv[drvidx]->stavail; > > - len = dev->drv[drvidx]->interface-> > > - readstat(buf, count, drvidx, > > - isdn_minor2chan(minor)); > > + len = dev->drv[drvidx]->interface->readstat(buf, count, > > + drvidx, isdn_minor2chan(minor)); > > + if (len < 0) { > > + retval = len; > > + goto out; > > + } > > } else { > > len = 0; > > } > > Seems appropriate for 2.4 too. Jeff, Karsten, no objection ? > Yes, OK for me. -- Karsten Keil SuSE Labs ISDN development - 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/