Re: [CGA-EXT] Possible DoS attack to DAD in SEND ?

["Laganier, Julien" <[e-mail]>]

Tony Cheneau wrote:
> [...] 
> This is the attack I described to the list in this mail:
> http://www.ietf.org/mail-archive/web/cga-ext/current/msg00057.html
> And then a thread (providing some other solutions):
> http://www.ietf.org/mail-archive/web/cga-ext/current/msg00075.html
>
> > A simple solution would be for the possible victim to discard
> > received DAD NSOLs for the same address that it has in tentative
> > state that have equal <public key, nonce, timestamp> than the DAD
> > NSOL that it had sent before.
> > (The probability of a legitimate collision in which another host that
> > generates a DAD NSOL with the same public address, nonce and
> timestamp
> > should be really low).
> Just comparing the nonce value should suffice.

So I understand a node receiving a DAD NS after having sent out a DAD NS happens when two nodes are performing DAD simultaneously as per RFC 4862.

If so, are you Tony suggesting that incoming DAD NS's with nonce similar to a nonce included in an outgoing DAD NS be discarded?

The probability that two nodes ends up generating the same public-private key should be zero unless the public key scheme is broken, so I think when a node receives a SEND protected message where the public key is the same as its own, the node MUST assumes the message was sent by himself and MUST discard the message.
 
--julien