Date: Thu, 30 Jun 2005 11:07:14 +1000 (EST) From: Mark Andrews <Mark_Andrews@isc.org> To: FreeBSD-gnats-submit@FreeBSD.org Subject: kern/82806: ipnat doesn't handle out of order fragments. Message-ID: <200506300107.j5U17Eak023708@bsdi.dv.isc.org> Resent-Message-ID: <200506300120.j5U1K6Om041349@freefall.freebsd.org>
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>Number: 82806 >Category: kern >Synopsis: ipnat doesn't handle out of order fragments. >Confidential: no >Severity: serious >Priority: medium >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Thu Jun 30 01:20:05 GMT 2005 >Closed-Date: >Last-Modified: >Originator: Mark Andrews >Release: FreeBSD 4.11-STABLE i386 >Organization: ISC >Environment: System: FreeBSD bsdi.dv.isc.org 4.11-STABLE FreeBSD 4.11-STABLE #22: Mon Jan 3 22:18:47 EST 2005 marka@bsdi.dv.isc.org:/usr/obj/usr/src/sys/BSDI i386 >Description: It looks like ipnat doesn't handle out of order fragments. >How-To-Repeat: Setup ipnat and try to make the following query from a machine behind the nat box. The response is large enough to cause fragmentation (DNS payload of 1734) and depending upon the fragment order you may or may not get a response. Using a 9.3.x version of dig. dig dlv gmail.com.dlv.verisignlabs.com @ns1.dlv.verisignlabs.com +dnssec Note: ipf is setup to handle out of order fragments. The above query always works on the nat box itself regardless of the fragment order (checked with "tcpdump -n -i sis0 -s 0 host 65.201.175.17" where sis0 is the external interface). Out of order fragments are not passed to the internal box (again checked w/ tcpdump on the the internal box). In order fragments are returned. >Fix: >Release-Note: >Audit-Trail: >Unformatted:
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