Re: [OSPF] FYI on draft-kini-ospf-fast-notification-01

[Wenhu Lu <[e-mail]>]

Hi Manav,
How would the data-plane auth verification prevent such DoS attacks?
Any replayed packets will go through.

Thanks,
-wenhu

________________________________
From: [e-mail] [mailto:[e-mail]] On Behalf Of Bhatia, Manav (Manav)
Sent: Wednesday, March 30, 2011 12:55 AM
To: Sriganesh Kini
Cc: [e-mail]
Subject: Re: [OSPF] FYI on draft-kini-ospf-fast-notification-01

Hi Sri,

This is regarding the point that i had raised yesterday - If the routers flood the "LSAs" in the data plane without verifying them, then we're leaving a hole open for DoS attacks, as any packet masquerading as a legitimate OSPF packet will get flooded on all routers. This is different from data packets flooding as these packets will be occupying the higest priority queues in both the ingress, egress and the CPU.

Second, what happens if the control packet is carrying an OSPF authentication digest? Would you still flood it without verifying the contents or would those be flooded regardless? I guess, you said that it would be the former. If thats the case, then this is not easy to do it in the HW as you would (i) need to parse the OSPF payload first to determine that its carrying a digest (ii) you would then need to verify it, which means you would be running HMAC-SHA in HW on the packet (given the Apad stuff that we have added in RFC5709 i dont think you can easily do this in HW) (iii) once the digest is verified you would need to flood it out on all the valid OSPF interfaces.

Cheers, Manav
________________________________
From: [e-mail] [mailto:[e-mail]] On Behalf Of Sriganesh Kini
Sent: Tuesday, March 29, 2011 9.20 PM
To: [e-mail]
Subject: [OSPF] FYI on draft-kini-ospf-fast-notification-01

Just an FYI to the list

This draft http://tools.ietf.org/html/draft-kini-ospf-fast-notification-01 was presented at the OSPF WG mtg today.

Thanks for the comments/questions at the mic. We will submit a new version addressing the comments.

Note that the other drafts related to Fast Notification (FN) are draft-lu-fn-transport and draft-lu-fast-notification-framework. These were presented in RTGWG.

Thanks

- Sri