From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261161AbVFJRoo (ORCPT ); Fri, 10 Jun 2005 13:44:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261159AbVFJRon (ORCPT ); Fri, 10 Jun 2005 13:44:43 -0400 Received: from smtp.osdl.org ([65.172.181.4]:58009 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S261154AbVFJRoX (ORCPT ); Fri, 10 Jun 2005 13:44:23 -0400 Date: Fri, 10 Jun 2005 10:44:14 -0700 From: Stephen Hemminger To: Alastair Poole Cc: linux-kernel@vger.kernel.org Subject: Re: BUG: Major TCP connect() errors, don't release as stable. Message-ID: <20050610104414.40fea891@router.routing.pdx.osdl.net> In-Reply-To: <42A9A0C0.5030802@unixtrix.com> References: <42A9A0C0.5030802@unixtrix.com> Organization: Open Source Development Lab X-Mailer: Sylpheed-Claws 1.0.4 (GTK+ 1.2.10; x86_64-unknown-linux-gnu) X-Face: &@E+xe?c%:&e4D{>f1O<&U>2qwRREG5!}7R4;D<"NO^UI2mJ[eEOA2*3>(`Th.yP,VDPo9$ /`~cw![cmj~~jWe?AHY7D1S+\}5brN0k*NE?pPh_'_d>6;XGG[\KDRViCfumZT3@[ 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 Fri, 10 Jun 2005 14:16:32 +0000 Alastair Poole wrote: > I have tested various kernels including 2.6.11.10 2.6.11.11 and > 2.6.12-rc6 and am having unusual results regarding connect(). Earlier > kernels do not return the same strange results. > > I have tested numerous basic port scanners, including my own, and > strangely ports which are NOT open are being reported as open. I have > checked these ports by various means -- to be certain they are NOT open > -- and in various runlevels; the results are the same. There are no TCP > daemons running, nor RPC services. This is definately kerenl related. > > The number of ports listed changes in size and they appear to be > random. For example, on one scan ports 22, 3455, 4532 and 6236 will > appear open; on another scan it might be 22, 3567, 3879, 3889, 6589 and > 7374. > > However, ports which ARE open do also appear as open alongside these > "rogue" ports. I have also tested this on another system with the same > results. It is also interesting to note that a basic TCP nmap scan of > all ports does not return these unusual results. > > I was initially told that the problem was not kernel related. However, > I have now reconfirmed with three seperate sources. This is, indeed, > quite a serious kernel related bug. Please take this seriously. > > Enclosed is example code that produces these results on the named > kernels and systems. > > sincerely > > Alastair Poole Looks like a simple interaction of "connect to self" allowed by RFC 793 to handle simultaneous connection and the TCP port randomization of ephemeral ports.