Missing BVCI in FLUSH_LL_ACK can cause segfault
The BVCI IE is listed as conditional and is only included if the flush action indicates that LLC-PDUs are transferred. (3GPP TS 48.018 Ch. 10.4.2).
The code in gbprox_rx_sig_from_bss unconditionally tries to get a BVCI from a FLUSH_LL message which could result in a segfault if no such IE is included.
- % Done changed from 0 to 30
Testcase in https://gerrit.osmocom.org/c/osmo-ttcn3-hacks/+/26372 to prove the segfault
- % Done changed from 30 to 60
gbproxy fix in https://gerrit.osmocom.org/c/osmo-gbproxy/+/26374
I believe this does what it's supposed to do, but the TTCN3 test still fails with:
Misc_Helpers.ttcn:15 setverdict(fail): none -> fail reason: ""BSSGP_Emulation.ttcnpp:820 : Couldn't find Component for TLLI 'C2180023'O"", new component reason: ""BSSGP_Emulation.ttcnpp:820 : Couldn't find Component for TLLI 'C2180023'O""
- % Done changed from 60 to 80
osmo-gbproxy patch is merged, TTCN3 test fixed in https://gerrit.osmocom.org/c/osmo-ttcn3-hacks/+/26382