The re-INVITE is a new transaction on an existing dialog
Kamailio acts as a proxy 
so in general it doesn't care about the dialog state ( even if you involve the dialog module - it still doesn't care )
Mostly re-INVITE should contain all information to how to reach the endpoint ( in Route headers) ( if topology hiding isn't involved, but if it is involved then the server knows about the dialog anyway )

So, if you receive a re-INVITE with Route set where your proxy is involved - you may consider this request belongs existing dialog and avoid authentication as it contains to and from tags, as well as the same Call-ID, which fully describes a particular session, into which your proxy is involved.
Even according https://www.rfc-editor.org/rfc/rfc3261.html#section-12.2 re-INVITEs MAY contain Record-Route headers, it would not affect the initial Routes set.

вт, 19 сент. 2023 г. в 11:00, Benoit Panizzon <benoit.panizzon@imp.ch>:
Hi List

At the moment, we challenge every invite (and re-invite) to make sure
the customer is authenticated.

Now we have one kind of PBX, which never does not authenticate when we
challenge a Re-Invite.

According to the vendor of that PBX's RFC interpretation, answering a
challenge to a re-invite is optional. If that is ignored by the PBX,
then the existing established dialog shall not end.

Unfortunately this causes the session timer to run out.

I am therefore wondering, if there is a safe way not to challenge
re-invites.

A Re-Invite contains a To-Tag. So I could bypass authentication on
presence of a to-Tag. But then, how do I prevent a customer to just set
a spoofed To-Tag to circumvent authentication?

Is there a feasible way?

Mit freundlichen Grüssen

-Benoît Panizzon-
--
I m p r o W a r e   A G    -    Leiter Commerce Kunden
______________________________________________________

Zurlindenstrasse 29             Tel  +41 61 826 93 00
CH-4133 Pratteln                Fax  +41 61 826 93 01
Schweiz                         Web  http://www.imp.ch
______________________________________________________
__________________________________________________________
Kamailio - Users Mailing List - Non Commercial Discussions
To unsubscribe send an email to sr-users-leave@lists.kamailio.org
Important: keep the mailing list in the recipients, do not reply only to the sender!
Edit mailing list options or unsubscribe: