Fix MM Auth: zero-initialize auth tuple before first use
Make sure a new auth tuple is initialized after
db_get_lastauthtuple_for_subscr() returns an error, i.e. if no tuple is present
for the subscriber yet.
Before this patch, the first key_seq depended on the typically uninitialized
value that was present in auth tuple's key_seq upon calling
auth_get_tuple_for_subscr().
The very first key_seq used for a new subscriber will now always be 0. Before,
it used to be mostly 1 ("(0 + 1) % 7"), but depended on whether the key_seq was
indeed initialized with 0, actually by random.
diff --git a/openbsc/tests/mm_auth/mm_auth_test.ok b/openbsc/tests/mm_auth/mm_auth_test.ok
index 9d89bfb..6c49f97 100644
--- a/openbsc/tests/mm_auth/mm_auth_test.ok
+++ b/openbsc/tests/mm_auth/mm_auth_test.ok
@@ -12,6 +12,10 @@
wrapped: db_get_lastauthtuple_for_subscr(): rc = -2
wrapped: db_sync_lastauthtuple_for_subscr(): rc = 0
auth_get_tuple_for_subscr(key_seq=0) --> auth_action == AUTH_DO_AUTH_THEN_CIPH
+wrapped: db_get_authinfo_for_subscr(): rc = 0
+wrapped: db_get_lastauthtuple_for_subscr(): rc = -2
+wrapped: db_sync_lastauthtuple_for_subscr(): rc = 0
+auth_get_tuple_for_subscr(key_seq=0) --> auth_action == AUTH_DO_AUTH_THEN_CIPH
* test_auth_then_ciph2()
wrapped: db_get_authinfo_for_subscr(): rc = 0