[sipcore] Draft new version: draft-ietf-sipcore-keep-07 [was: Comments on draft-ietf-sipcore-keep-05]

Hi,

I've submitted a new version of the keep-alive draft.

The changes are:

- I added the text suggested by Adam to the security considerations section.
- Small minor change in the 4th paragraph of section 4.1, as suggested by Paul earlier (after -06 had been submitted).

Regards,

Christer

> -----Original Message-----
> From: sipcore-bounces@ietf.org 
> [mailto:sipcore-bounces@ietf.org] On Behalf Of Christer Holmberg
> Sent: 13. lokakuuta 2010 19:07
> To: Adam Roach
> Cc: sipcore@ietf.org; Gonzalo Camarillo; Hadriel Kaplan
> Subject: Re: [sipcore] Comments on draft-ietf-sipcore-keep-05
> 
> 
> Your text proposal looks good. I can add it.
> 
> Regards,
> 
> Christer 
> 
> > -----Original Message-----
> > From: Adam Roach [mailto:adam@nostrum.com]
> > Sent: 13. lokakuuta 2010 18:57
> > To: Christer Holmberg
> > Cc: sipcore@ietf.org; Hadriel Kaplan; rjsparks@nostrum.com; Gonzalo 
> > Camarillo
> > Subject: Re: Comments on draft-ietf-sipcore-keep-05
> > 
> > 
> >   On 10/13/10 10:28 AM, Christer Holmberg wrote:
> > > Hi,
> > >
> > >>>> a) Any downstream SIP entity, beyond the adjacent
> > downstream peer
> > >>>> node, can modify the Via header identifying the local
> > node and thus
> > >>>> cause the local node to send keepalives to its 
> adjacent peer (at 
> > >>>> high rates) if the peer does not support
> > >>> ...
> > >>> Nothing was added regarding a),because entities can 
> always check 
> > >>> that, before forwarding responses, the the Via header
> > field hasn't
> > >>> been tempered with.
> > >> The purpose of the "Security Considerations" section is to warn 
> > >> implementors about things they need to take into 
> consideration to 
> > >> avoid security problems. Shouldn't the document at least
> > suggest that
> > >> implementations validate the Via header field to prevent
> > this kind of
> > >> attack?
> > > Fair enough.
> > >
> > > I can add the following text:
> > >
> > >     "Downstream SIP entities can modify Via header fields
> > identifying other SIP entities,
> > >     and cause keepalives to be sent (at hight rates) to
> > entities that do not not support
> > >     the keepalive mechanism. SIP entities can prevent this,
> > when a SIP response is received,
> > >     by validating that Via headers have not been modified
> > in a way which would cause such
> > >     sending of keepalives."
> > 
> > That's good, but I think we can improve it by more clearly 
> calling out 
> > what the implementations need to look for:
> > 
> > "Downstream SIP entities can modify Via header fields identifying 
> > other SIP entities, and cause keepalives to be sent (at 
> high rates) to 
> > entities that do not not support the keepalive mechanism. 
> SIP entities 
> > can prevent this, when a SIP response is received, by 
> examining their 
> > own Via header field to determine that downstream entities have not 
> > added a 'keep' parameter or set an existing 'keep' parameter to a 
> > value not supported by the implementation."
> > 
> > /a
> > 
> > 
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