Subject: [Ecrit] re - LoST-Synchronization & Loop prevention?

From: Hannes Tschofenig <[email-masked]>
Date: Sat, 06 Mar 2010 22:41:05 +0200

Hi Alex,

thanks a lot for your feedback. We should definitely capture it in the 
document.
The security aspect of came up in the context of LoST when the 
synchronization mechanisms was still meant to go into what is now RFC 
5222. http://tools.ietf.org/html/rfc5582#section-10 captures some of the 
aspects. Mentioning the loop aspect is a very good idea.

I have updated the draft.

Ciao
Hannes

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Hello,

I've just thought about something that i haven't seen discussed in any
of the documents yet. Assume that there are 3 forest guides, which have
the following "sync relations".

     A -------- B
      \        /
       \      /
        \    /
         \  /
          C

Assuming that "A" gets updated, it would then send Sync messages to B
(and probably C). B in turn would probably redistribute the message
received from A over to C (because from the perspective of B, it
compromises new information to be distributed) - B wouldn't know that C
has already received the information from A directly. 

I understand that "source", "sourceid" and "last updated" could be used
to identify whether a message has already been seen. However, my guts
feeling tells me that there could be situations in which a FG rewrites
information that it has received, and essentially creates messages that
cannot be correlated with the original message (or, simple
implementation problems...) 

I understand it looks like NNTP - I'm just curious if loop prevention
has been considered, and discussed in detail ... "injecting" a loop into
the global network of FGs could be a very effective DoS attack...

Alex

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