Date: Fri, 13 Aug 2004 09:31:21 GMT From: Mark Andrews <marka@isc.org> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/70399: ipfilter breaks IPv6 path mtu discovery Message-ID: <200408130931.i7D9VLtG012186@www.freebsd.org> Resent-Message-ID: <200408130940.i7D9eNMg070869@freefall.freebsd.org>
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>Number: 70399
>Category: kern
>Synopsis: ipfilter breaks IPv6 path mtu discovery
>Confidential: no
>Severity: critical
>Priority: high
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Fri Aug 13 09:40:23 GMT 2004
>Closed-Date:
>Last-Modified:
>Originator: Mark Andrews
>Release: 4.10 stable
>Organization:
ISC
>Environment:
FreeBSD bsdi.dv.isc.org 4.10-STABLE FreeBSD 4.10-STABLE #11: Fri Aug 13 15:27:12 EST 2004 marka@bsdi.dv.isc.org:/usr/obj/usr/src/sys/BSDI i386
>Description:
icmp6_error() prepends a mbuf to send ICMP6_PACKET_TOO_BIG. When
ipfilter is active there is a attempt to pullup the full packet
which fails because there is not a associated cluster.
ICMP6_TIME_EXCEEDED can also demonstate the problem if traceroute6
uses a size of 105 or greater.
>How-To-Repeat:
have a inbound interface w/ a mtu of 1500 and a output interface
with a mtu of 1280 (e.g. gif). Have ipf active. Attempt to send
a packet > 1280 octets through the router. The ICMP6_PACKET_TOO_BIG
packet is dropped before it is emitted.
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted:
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