[Midnightbsd-cvs] src: pf.c: Correct the following defect in PF, originally reported to

[laffer1 at midnightbsd.org]

Log Message:
-----------
Correct the following defect in PF, originally reported to OpenBSD and later in our #midnightbsd chatroom:

Author           : Rembrandt 
Date             : 2009-04-09 
Affected Software: OpenBSD Kernel 
Affected OS      : OpenBSD 4.{3,4,5}, OpenBSD-current 
                  Propably older versions are affected as well 
Type             : Denial of Service 

OSVDB            : 
Milw0rm          : 8406 
CVE              : 
ISS X-Force:     : 
BID              : 34482 
Secunia          : 34676 
VUPEN ID         : 
Trying to fix it responsible and get in contact with the vendor: 

-- OpenBSD -- 
Contacted               2009-04-09 15:35 GMT+1 
Patch avaiable          2009-04-11 23:43 UTC 

We received no response nor a notification about an upcoming patch by 
the developers. 
-- END -- 

OpenBSDs PF firewall in OpenBSD 4.3 up to OpenBSD-current is prone to a 
remote Denial of Service during a null pointer dereference in relation with 
special crafted IP datagrams. If the firewall handles such a packet the kernel 
panics. 


Steps to reproduce: 

If you are behind a OpenBSD firewall this nmap scan should trigger the problem 
and crash your firewall device: 

nmap -sO $some_host_so_that_the_firewall_handles_the_packets 

For more informations please do read the patch issued by OpenBSD. 


Patches and Workaround: 

Patches are provided for OpenBSD 4.3, 4.4, 4.5 (upcoming, release 1st of may) 
and OpenBSD-current (via CVS only) and are avaiable at the errata website. 
The developers provide hints for a workaround at their errata website too. 



Kind regards, 
Rembrandt

Modified Files:
--------------
    src/sys/contrib/pf/net:
        pf.c (r1.3 -> r1.4)
        (http://cvsweb.midnightbsd.org/src/sys/contrib/pf/net/pf.c?r1=1.3&r2=1.4)