Re: [tsvwg] Checksums in UDP options

["C. M. Heard" <[e-mail]>]

On Thu, Sep 6, 2018 at 12:10 PM Tom Herbert wrote:
> On Thu, Sep 6, 2018 at 12:00 PM, C. M. Heard wrote:
> > On Thu, Sep 6, 2018 at 11:30 AM Tom Herbert wrote:
> > Indeed, in the DNS case, the negotiation I describe is safe only if
> > the server does not retain memory of the client's ability to use FRAG
> > across transactions. The negotiation has to apply to exactly one
> > request -- which is what I was implicitly assuming. But subject to
> > that proviso, I fail to see any security vulnerabilities (either from a
> > spoofing attack or a MITM attack) that do not already exist today.
> >
> > I grant that this is a special case, but I believe that it is a potentially
> > important special case (though the DNSOP folks may not agree --
> > see draft-song-atr-large-resp for an alternative approach).
> >
> I'm not sure I would call DNS a special case. Isn't that one of the
> biggest users of UDP on the Internet?

That is my understanding. I call it a special case because of the
strict request-response pairing.

> > Again, though, you bring up a good point: negotiating the use of
> > options that transform the data can introduce security vulnerabilities
> > unless there is some means to authenticate the remote peer.
> >
> Look at it this way, we've spent about forty years trying to get TCP
> handshake to be secure and efficient and it's still not perfect. These
> are not easy problems to solve! :-)

Indeed.

Mike Heard