17 May
2018
17 May
'18
4:02 p.m.
On Thu, May 17, 2018 at 11:48:48AM +0100, Asgaroth wrote:
I was looking at the wording for nonce_count
https://www.kamailio.org/docs/modules/5.1.x/modules/auth.html#auth.p.nonce_…
"3.5. nonce_count (boolean)
If enabled the received nc value is remembered and checked against the
older value (for a successful authentication the received nc must be
greater then the previously received one, see rfc2617 for more details).
This will provide protection against replay attacks while still allowing
credentials caching at the UA side."
It sounds like this is kept in memory. Since this isn't shared between
kamailio instances, the discrepancies in nonce count should trigger the
replay attack prevention mechanism (i.e. offer a new challenge).
So I guess this is indended behavior.
This works
with all auth params set to default. My guess the following
are the cause of problems.
Daniel, *thank you*, this was exactly what was causing the issue, disabled
the above two module parameters and, boom, it started working.
I wonder why these particular module parameters would break the
functionality though, I thought the idea was that each proxy would be able
to generate the nonce with a shared secret if it recieved a challenge
response from a ua who's nonce was generated on a different proxy. Is this a
bug, or, is it working as intended when these two module paramters are
enabled? > modparam("auth",
"nonce_count", 1)
> modparam("auth", "one_time_nonce", 1)