Subject: [karp] Security Extension for OSPFv2 when using Manual Key Management

From: "Bhatia, Manav (Manav)" <[email-masked]>
Date: Tue, 15 Feb 2011 06:57:44 +0530

Hi,

We have posted the revised version of the Security extension for OSPFv2 using Manual Keying draft and its available here:
http://www.ietf.org/id/draft-bhatia-karp-ospf-ip-layer-protection-03.txt

You can look at the diffs from the last version here:
http://tools.ietf.org/rfcdiff?url2=draft-bhatia-karp-ospf-ip-layer-protection-03.txt

This suggests another mechanism that could be used for protecting OSPF against inter-session and intra-session replay attacks besides some other changes.

Would appreciate a feedback from the WG(s).

Cheers, Manav

--
Manav Bhatia,
IP Division, Alcatel-Lucent,
Bangalore - India

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From: Sam Hartman <[email-masked]>
Date: Tue, 15 Feb 2011 10:52:36 -0500

At this point I think we've reduced the impact of the nonce/session Id
approach significantly.

I believe no extra packets are required in a cold start situation of the
entire network.  Whenever a router crashes and reboots then routers
wishing to form an adjacency with that router will generate an extra
hello (or take a bit longer to bring up the adjacency).  Receiver
processing has been optimized.  If you receive a packet for an existing
adjacency, you need to compare 1 32-bit number over what you do today.

Worst case, you need to compare 2 32-bit numbers and write 2 32-bit
quantities into your neighbor structure; that's only when setting up an
adjacency.  I feel significantly more confident in the security
properties of the nonce solution than the boot count solution, although
it's possible after sufficient analysis both will be fine.  Both types
of solutions can potentially be sound from a security standpoint; the
interesting question is whether we've properly fit security primitives
to what goes on in OSPF.  Guaranteeing freshness as is done in the nonce
solution is more conservative and easier to analyze.