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Date: 10 Aug 2001 12:04:43 -0000
From: Przemyslaw Frasunek <venglin@freebsd.lublin.pl>
Reply-To: Przemyslaw Frasunek <venglin@freebsd.lublin.pl>
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Subject: kern/29602: kernel doesn't check if newly allocated ephemerical port is occupied by ipnat rdr
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>Number:         29602
>Category:       kern
>Synopsis:       kernel doesn't check if newly allocated ephemerical port is occupied by ipnat rdr
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Fri Aug 10 05:10:01 PDT 2001
>Closed-Date:
>Last-Modified:
>Originator:     Przemyslaw Frasunek
>Release:        FreeBSD 4.3-STABLE i386
>Organization:
czuby.net
>Environment:
System: FreeBSD lagoon.freebsd.lublin.pl 4.3-STABLE FreeBSD 4.3-STABLE #0: Wed Jul 18 11:43:39 CEST 2001 root@riget.scene.pl:/mnt/lagoon/usr/src/sys/compile/RIGET i386

With ipfilter+ipnat.

>Description:

	When ephemerical port is allocated for outgoing connection, kernel
	doesn't check if port is already occupied by ipnat redirection.

	Such condition is very rare, but still possible:

intercom:root:/usr/src/sys/netinet# ipnat -l | grep 3389
rdr fxp0 195.205.36.110/32 port 3389 -> 192.168.0.100 port 3389 tcp
RDR 192.168.0.100   3389  <- -> 195.205.36.110  3389  [212.2.96.35 80]

	Source of redirected connection seems to be 212.2.96.35:80, which
	is impossible. 212.182.96.35:80 is destination of connection
	initiated from 195.205.36.110:3389 from local machine.

>How-To-Repeat:

	Set up an ipnat redirection on low epheremical port and do some
	connect()s.

>Fix:

	Unknown.
>Release-Note:
>Audit-Trail:
>Unformatted:

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