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, 24 Apr 2002 14:11:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 24 Apr 2002 14:10:59 -0400 Received: from panic.tn.gatech.edu ([130.207.137.62]:12454 "HELO gtf.org") by vger.kernel.org with SMTP id ; Wed, 24 Apr 2002 14:10:57 -0400 Date: Wed, 24 Apr 2002 14:10:55 -0400 From: Jeff Garzik To: Ben Greear Cc: "David S. Miller" , jd@epcnet.de, linux-kernel@vger.kernel.org Subject: Re: AW: Re: AW: Re: VLAN and Network Drivers 2.4.x Message-ID: <20020424141055.A20763@havoc.gtf.org> In-Reply-To: <20020424.093515.82125943.davem@redhat.com> <721506265.avixxmail@nexxnet.epcnet.de> <20020424.095951.43413800.davem@redhat.com> <3CC6EBF1.9060902@candelatech.com> <20020424134933.A17852@havoc.gtf.org> <3CC6F3BF.8050504@candelatech.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 24, 2002 at 11:04:47AM -0700, Ben Greear wrote: > Jeff Garzik wrote: > > > On Wed, Apr 24, 2002 at 10:31:29AM -0700, Ben Greear wrote: > > > >>Also, is there any good reason that we can't get at least a compile > >>time change into some of the drivers like tulip where we know we can > >>get at least MOST of the cards supported with a small change? > >> > > > > The tulip patch is butt-ugly - the oversized allocation isn't needed, > > and it just flat-out turns off large packet protection. That's really > > not what you want to do, even for the best tulip cards. If an oversized > > gram (non-VLAN) makes it into a network which such a patched tulip > > driver, you can DoS. So, I view the current tulip patch as unacceptable > > too -- for security reasons, we should not even take it as a compile > > time patch. (and I recommend against using that patch on production > > machines, for the same security reasons) > > > I can DOS a tulip card with very small packets too ;) A tulip card? Or the stack? Can you DoS it when CONFIG_NET_HW_FLOWCONTROL is enabled? That's basically NAPI without the fancy acronym... > > The proper tulip patch does not need to change packet allocation size > > at all (it's already plenty big enough), and it needs to copy the RX > > fragment handling code from 8139cp (which is admittedly ugly, slow path) > > or write fresh fragment handling code. Along with that fragment > > handling code comes a safe way to do VLAN, and non-standard large MTUs > > in general. > > In the general case, where the packets are only 1518 (ie no DoS or mis-configured > hardware is in effect), is there a need for the "ugly, slow path" code to run? It depends on the chip, but most generally: no Jeff