Re: [secdir] secdir review of draft-ietf-siprec-metadata-20

[David Mandelberg <[e-mail]>]

On 02/15/2016 12:18 AM, Paul Kyzivat wrote:
> On 2/14/16 4:03 PM, David Mandelberg wrote:
>> Section 6.10 says that "multiple SRC's [clients] can refer to the same
>> element/UUID (how each SRC learns the UUID here is out of scope of
>> SIPREC)". But what happens if two clients try to define different
>> objects with the same UUID? Does one of the objects take precedence for
>> all clients? If all of the benign clients are relying on referencing an
>> object A with UUID 1, and a malicious client is able to send an object B
>> also with UUID 1, that might compromise the integrity of the metadata
>> sent by the benign clients. This could be mitigated by requiring that
>> UUIDs are generated (pseudo-)randomly and are kept confidential from
>> potential adversaries, but I don't think the draft says either of these
>> things.
> 
> The UUIDs used in the metadata are intended to be *unique*. Distinct
> SRCs that construct new UUIDs are expected to follow the rules for
> constructing them so that they are indeed unique.

Yes, but a malicious SRC probably won't do what you're expecting of a
benign SRC. I agree that the text in the draft is good *if* it were true
that all SRCs are benign.


> If two SRCs use the same UUID it will be because they intentionally
> choose to do so.

Or because the malicious SRC is intentionally choosing to do so, without
permission or cooperation from the benign SRC.

> Typically this will be by some back channel to
> communicate among themselves. (I suppose there could potentially be some
> algorithmic way for them to construct UUIDs in a coordinated way, but I
> won't speculate on that.)
> 
> By design there should be no accidental reuse of UUIDs.

I agree. I'm worried only about malicious reuse of UUIDs.

> 
>     Thanks,
>     Paul
> 


-- 
David Eric Mandelberg / dseomn
http://david.mandelberg.org/