From 890cab2e5b46c540673b5221c811b6ebfdcbcfd5 Mon Sep 17 00:00:00 2001 From: Philipp Maier Date: Mon, 1 Aug 2022 17:24:18 +0200 Subject: bsc_subscr_conn_fsm: fix use after free In cases where the MGCP client endpoint FSM is terminating early the bsc sbscr conn FSM receives the signal GSCON_EV_FORGET_MGW_ENDPOINT, which then calls gscon_forget_mgw_endpoint(). However, this only nulls the conn->user_plane->mgw_endpoint_ci_msc struct pointer, not the others. This causes the assignment FSM to access conn->assignment.created_ci_for_msc whle trying to initiate a DLCX. We must make sure that when the MGCP client endpoint FSM dies, that all other CI pointers that reference the same CI are also set to NULL. Related: OS#5572 --- src/osmo-bsc/bsc_subscr_conn_fsm.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/src/osmo-bsc/bsc_subscr_conn_fsm.c b/src/osmo-bsc/bsc_subscr_conn_fsm.c index 9af28c787..7c0c7c3a4 100644 --- a/src/osmo-bsc/bsc_subscr_conn_fsm.c +++ b/src/osmo-bsc/bsc_subscr_conn_fsm.c @@ -940,6 +940,10 @@ static void gscon_forget_mgw_endpoint(struct gsm_subscriber_connection *conn) mgcp_client = osmo_mgcpc_ep_client(conn->user_plane.mgw_endpoint); mgcp_client_pool_put(mgcp_client); + /* Be sure that the endpoint CI we are maintaining in user_plane + * is also removed from the other locations as well. */ + gscon_forget_mgw_endpoint_ci(conn, conn->user_plane.mgw_endpoint_ci_msc); + conn->user_plane.mgw_endpoint = NULL; conn->user_plane.mgw_endpoint_ci_msc = NULL; conn->ho.created_ci_for_msc = NULL; -- cgit v1.2.3