Fix MM Auth: disallow key_seq mismatch
In auth_get_tuple_for_subscr(), add missing condition to match incoming
key_seq with stored key_seq, so that re-authentication is requested for
mismatching key_seqs.
Add test for this issue.
diff --git a/openbsc/tests/mm_auth/mm_auth_test.ok b/openbsc/tests/mm_auth/mm_auth_test.ok
index 7dedadc..9d89bfb 100644
--- a/openbsc/tests/mm_auth/mm_auth_test.ok
+++ b/openbsc/tests/mm_auth/mm_auth_test.ok
@@ -28,3 +28,9 @@
wrapped: db_get_lastauthtuple_for_subscr(): rc = 0
wrapped: db_sync_lastauthtuple_for_subscr(): rc = 0
auth_get_tuple_for_subscr(key_seq=3) --> auth_action == AUTH_DO_CIPH
+
+* test_auth_reuse_key_seq_mismatch()
+wrapped: db_get_authinfo_for_subscr(): rc = 0
+wrapped: db_get_lastauthtuple_for_subscr(): rc = 0
+wrapped: db_sync_lastauthtuple_for_subscr(): rc = 0
+auth_get_tuple_for_subscr(key_seq=4) --> auth_action == AUTH_DO_AUTH_THEN_CIPH