Re: [Roll] Roman Danyliw's No Objection on draft-ietf-roll-turnon-rfc8138-14: (with COMMENT)

[Roman Danyliw <[e-mail]>]

Hi Pascal!

> -----Original Message-----
> From: Pascal Thubert (pthubert) <[e-mail]>
> Sent: Thursday, September 10, 2020 8:31 AM
> To: Roman Danyliw <[e-mail]>; The IESG <[e-mail]>
> Cc: [e-mail]; [e-mail]; [e-mail];
> Ines Robles <[e-mail]>; [e-mail]
> Subject: RE: Roman Danyliw's No Objection on draft-ietf-roll-turnon-rfc8138-
> 14: (with COMMENT)
> 
> Hello Roman 😊
> 
> > > The "T" flag is in a message (the DIO) that is propagated in a
> > > fashion that is akin to multicast though it's not. The RPL node
> > > receives DIO messages from neighbors that are willing to be parents.
> > > If this node decides to also be a parent, it will regenerate a DIO
> > > that contains some fields unchanged, including the DODAG configuration
> option.
> > >
> > > In that process, the bad guy may change some fields it shouldn't,
> > > including the "T" flag, but it's just one of many fields in that
> > > same situation. His children and their descendant will repeat that
> > > wrong setting. Note that this is not a tree but a DODAG. So you get
> > > DIOs from not
> > one (candidate) parent but multiple ones.
> > > A descendant may discover an inconsistency between its parents (if
> > > some descend from the attacker and others do not) and could raise an
> > > alert, but the case can be normal, e.g., during a transition. RPL
> > > does not really specify that, it is left to implementations, e.g.,
> > > constrained nodes will not spend code looking for anomalies.
> > >
> > > Bottom line, there is no path to be on. There's a wave coming, the
> > > attacker relays that wave, and modifies it. If it is in the middle
> > > of the network this has an effect - on its descendants. If the
> > > attacker is at the leaf edge, the attack as no effect since this node has no
> descendant.
> > >
> > > What do you think?
> >
> > Understood.  I now appreciate the vagueness of the original words.
> > I'm trying to find an alternative to using "middle of the network"
> > since this doesn't convey for me the hierarchy you are describing.  See below:
> >
> > > > OLD
> > > > An attacker in the middle of the network may reset the "T" flag to
> > > > cause extra energy spending in its subDAG.
> >
> > NEW
> > An attacker may reset the "T" flag to force additional energy
> > consumption of child or descendant nodes in its subDAG.
> >
> > Regards,
> 
> I love it, Roman!
> 
> I'll be holding the publication till Alvaro and Benjamin reach an agreement on
> whether this updates RFC 6550 or not.
> 
> Till then I committed the diffs as  https://github.com/roll-wg/roll-turnon-
> rfc8138/commit/80fa3425e8c0c60a8482ddb2583f75f405fe490a
> 
> Please let me know if we are good now.

Looks good to me!  Thanks for the quick turnaround.

Regards,
Roman