Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262834AbTELWB7 (ORCPT ); Mon, 12 May 2003 18:01:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262858AbTELWBz (ORCPT ); Mon, 12 May 2003 18:01:55 -0400 Received: from 216-239-45-4.google.com ([216.239.45.4]:4563 "EHLO 216-239-45-4.google.com") by vger.kernel.org with ESMTP id S262834AbTELWAe (ORCPT ); Mon, 12 May 2003 18:00:34 -0400 Date: Mon, 12 May 2003 15:13:12 -0700 From: Frank Cusack To: Paul Mackerras Cc: linux-kernel@vger.kernel.org Subject: Re: MPPE in kernel? Message-ID: <20030512151312.C30310@google.com> References: <20030512045929.C29781@google.com> <16063.38221.73659.403481@argo.ozlabs.ibm.com> <20030512060210.C29881@google.com> <16063.40072.101121.244892@argo.ozlabs.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: <16063.40072.101121.244892@argo.ozlabs.ibm.com>; from paulus@samba.org on Mon, May 12, 2003 at 11:07:20PM +1000 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1451 Lines: 39 On Mon, May 12, 2003 at 11:07:20PM +1000, Paul Mackerras wrote: > Frank Cusack writes: > > > I have the compressor return a 3-valued return code (<0, 0, >0) instead of > > two-valued (>0, other). A negative value tells ppp_generic to drop the > > packet. 0 means the same as it does now--the compressor failed for some > > reason. (All current compressors always return 0 or >0, so the negative > > return is compatible.) > > > > 0 could also mean that CCP isn't up yet, but pppd userland doesn't allow > > NCP's to come up until CCP completes (iff trying to negotiate MPPE). > > Hmmm, and are you sure that nothing can cause CCP to go down? If it > does then ppp_generic will send data uncompressed. What would happen > if an attacker managed to insert a CCP terminate-request into the > receive stream somehow? When (if) CCP goes down, pppd shuts down LCP if MPPE was running. This could move into the kernel if you think it's better that way, but I think userland is ok. static void ccp_input(unit, p, len) { ... #ifdef MPPE if (ccp_gotoptions[unit].mppe) { error("MPPE disabled, closing LCP"); lcp_close(unit, "MPPE disabled by peer"); } #endif } /fc - 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/