Cellular Network Infrastructure » Core Network (CN) » OsmoSGSN

Test all of these:

• No authentication
• GSM AKA
• UMTS AKA without AUTS sync
• UMTS AKA with AUTS sync
• UMTS AKA in pre-R99 compatibility mode

Having in mind something like the msc_vlr tests where messages are fabricated
from the MS and the HLR sides from hex strings to play through the various cases.
https://git.osmocom.org/openbsc/tree/openbsc/tests/msc_vlr?h=neels/vlr

Instead of a unit test, this could also be performed from a to-be-implemented SGSN test in TTCN-3.

neels with GSM AKA you mean the old SRES based auth?
neels what's UMTS aka in pre-R99 compatibility?

I meant the second from the right, where everything is R99, i.e. UMTS capable, except for the MS.
So both HLR, SGSN and USIM can do UMTS, but the phone ignores / will not send AUTN and XRES.

Another valid variant of this that we see in the field is that the MS is R99, but it actually decides to not do UMTS aka.
So we send out AUTN to it, but it chooses to respond only with an SRES.

See vlr_auth_fsm.c in osmo-msc: auth_fsm_wait_auth_resp() and check_auth_resp().

For tests, see:

• msc_vlr_test_gsm_authen.c, test_gsm_milenage_authen() for pre-R99 with Milenage (UMTS in GSM compat mode)
  A log transcript of what happens is in osmo-msc/tests/msc_vlr/msc_vlr_test_gsm_authen.err

• msc_vlr_test_umts_authen.c, test_umts_authen_only_sres_geran(), for an R99 MS responding with GSM AKA.
  osmo-msc/tests/msc_vlr/msc_vlr_test_umts_authen.err

(shouldn't this issue be "in progress"?)

• UMTS AKA in pre-R99 compatibility mode added is already checked since 0ecb2e351649 ("sgsn: test umts aka with gsm sres response")
  [Wed May 2 09:14:36 2018]
  test case: SGSN.TC_attach_umts_aka_gsm_sres
• GSM AKA is checked by:
  test case: SGSN.TC_attach

The only missing point here is the UTRAN UMTS AKA auth check, but as long we don't have a RANAP TTCN3 implementation we can not do that.