bsc: Fix crash that can occur on RF Failure
When we got a clear request we did not clear the internal
association between the gsm_subscriber_connection and the SCCP
part. When we got a DTAP message before the CLEAR COMMAND we
will end up in a crash as the ->bts pointer of the connection
has been cleared.
#0 bsc_scan_msc_msg (conn=0xde178, msg=<value optimized out>) at osmo_bsc_filter.c:258
#1 0x000112c8 in bsc_handle_dt1 (conn=0xdebd8, msg=0xd1f58, len=<value optimized out>) at osmo_bsc_bssap.c:507
#2 0x00010208 in msc_outgoing_sccp_data (conn=<value optimized out>, msg=0xdfacc, len=858696) at osmo_bsc_sccp.c:73
#3 0x0003c110 in sccp_system_incoming (msgb=0xd1f58) at sccp.c:1064
diff --git a/openbsc/src/osmo-bsc/osmo_bsc_api.c b/openbsc/src/osmo-bsc/osmo_bsc_api.c
index d02b0b5..2869f47 100644
--- a/openbsc/src/osmo-bsc/osmo_bsc_api.c
+++ b/openbsc/src/osmo-bsc/osmo_bsc_api.c
@@ -159,19 +159,28 @@
static int bsc_clear_request(struct gsm_subscriber_connection *conn, uint32_t cause)
{
+ struct osmo_bsc_sccp_con *sccp;
struct msgb *resp;
return_when_not_connected_val(conn, 1);
LOGP(DMSC, LOGL_INFO, "Tx MSC CLEAR REQUEST\n");
+ /*
+ * Remove the connection from BSC<->SCCP part, the SCCP part
+ * will either be cleared by channel release or MSC disconnect
+ */
+ sccp = conn->sccp_con;
+ sccp->conn = NULL;
+ conn->sccp_con = NULL;
+
resp = gsm0808_create_clear_rqst(GSM0808_CAUSE_RADIO_INTERFACE_FAILURE);
if (!resp) {
LOGP(DMSC, LOGL_ERROR, "Failed to allocate response.\n");
- return 0;
+ return 1;
}
- bsc_queue_for_msc(conn->sccp_con, resp);
- return 0;
+ bsc_queue_for_msc(sccp, resp);
+ return 1;
}
static struct bsc_api bsc_handler = {