kernel/1816: Repetable crashes of ipfilter code

[venglin@freebsd.lublin.pl]

>Number:         1816
>Category:       kernel
>Synopsis:       Repetable crashes of ipfilter code
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    bugs
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue May  8 00:00:02 MDT 2001
>Last-Modified:
>Originator:     Przemysław Frasunek
>Organization:
net
>Release:        2.9-beta
>Environment:
	System      : OpenBSD 2.9
	Architecture: OpenBSD.i386
	Machine     : i386

	OpenBSD 2.9-beta installed from snapshot as of 23 Apr 2001.
	Ipfilter+ipnat enabled.

>Description:

	Sending ICMP ECHO with record route, directed to OpenBSD box
	with ipfilter enabled, causes 'panic: in_cksum: mp == NULL'.

	Fully repetable when ipfilter is enabled.

>How-To-Repeat:

	ping -R <ip of openbsd box>

>Fix:
	Unknown.

>Audit-Trail:
>Unformatted: