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authorPhilipp Maier <pmaier@sysmocom.de>2018-03-19 16:06:12 +0100
committerPhilipp Maier <pmaier@sysmocom.de>2018-03-19 16:12:31 +0100
commit2a98a73be4fbd361d372e28c79a2fc2dc37709fe (patch)
tree41af5ebccdc750673699e9c4fcace03ed25b12f1
parentcd6685767140891d1d21b76e6ce65549dce1b994 (diff)
MSC_Tests: Test what happens when the DLCX is dropped
Test the reaction of osmo-msc when the DLCX at the end of a call is not answered. Normally osmo-msc should time out and clear the connection. Change-ID osmo-msc:I78f1b6a9149488a4ad3f120c1e190a83c07d4b89 fixes a regression that causes osmo-msc to segfault due to a use after free. This testcase provokes the situation that leads to the crash. Change-Id: Ic124ea116496209f9a1d8e74ae3e3a36cf866db0 Related OS#2881 Related OS#2882
-rw-r--r--msc/BSC_ConnectionHandler.ttcn24
-rw-r--r--msc/MSC_Tests.ttcn40
2 files changed, 58 insertions, 6 deletions
diff --git a/msc/BSC_ConnectionHandler.ttcn b/msc/BSC_ConnectionHandler.ttcn
index 1704c18..72e2a4e 100644
--- a/msc/BSC_ConnectionHandler.ttcn
+++ b/msc/BSC_ConnectionHandler.ttcn
@@ -373,6 +373,8 @@ type record CallParameters {
PortNumber mgw_rtp_port_mss, /* MSS-facing MGW RTP Port */
uint7_t rtp_payload_type, /* dynamic RTP payload type */
charstring rtp_sdp_format, /* AMR/8000 or the like */
+ boolean mgw_drop_dlcx optional, /* Provoke errors by not responding to DLCX
+ (f_mt_call and f_mt_call) */
MgcpCallId mgcp_call_id optional, /* MGCP Call ID; CallAgent allocated */
MgcpEndpoint mgcp_ep optional /* MGCP Endpoint, CallAgent or MGW allocated */,
@@ -410,6 +412,7 @@ runs on BSC_ConnHdlr {
var MobileIdentityLV mi;
var MNCC_PDU mncc;
var MgcpCommand mgcp_cmd;
+ var boolean respond_to_dlcx;
f_bssmap_register_imsi(g_pars.imsi, g_pars.tmsi);
@@ -510,6 +513,8 @@ runs on BSC_ConnHdlr {
BSSAP.receive(tr_PDU_DTAP_MT(tr_ML3_MT_CC_REL_COMPL(cpars.transaction_id)));
}
+ respond_to_dlcx := not (isbound(cpars.mgw_drop_dlcx) and valueof(cpars.mgw_drop_dlcx));
+
/* clearing of radio channel */
interleave {
[] BSSAP.receive(tr_BSSMAP_ClearCommand) {
@@ -517,9 +522,11 @@ runs on BSC_ConnHdlr {
BSSAP.receive(BSSAP_Conn_Prim:MSC_CONN_PRIM_DISC_IND);
}
[] MGCP.receive(tr_DLCX(?)) -> value mgcp_cmd {
- /* TODO: For one or all connections on EP? */
- MGCP.send(ts_DLCX_ACK2(mgcp_cmd.line.trans_id));
- f_create_mgcp_delete_ep(cpars.mgcp_ep);
+ if (respond_to_dlcx) {
+ /* TODO: For one or all connections on EP? */
+ MGCP.send(ts_DLCX_ACK2(mgcp_cmd.line.trans_id));
+ f_create_mgcp_delete_ep(cpars.mgcp_ep);
+ }
}
}
setverdict(pass);
@@ -531,6 +538,7 @@ runs on BSC_ConnHdlr {
var MobileIdentityLV mi;
var MNCC_PDU mncc;
var MgcpCommand mgcp_cmd;
+ var boolean respond_to_dlcx;
/* If we have a TMSI, use TMSI instead of IMSI */
if (ispresent(g_pars.tmsi)) {
@@ -628,6 +636,8 @@ runs on BSC_ConnHdlr {
BSSAP.receive(tr_PDU_DTAP_MT(tr_ML3_MT_CC_RELEASE(cpars.transaction_id)));
BSSAP.send(ts_PDU_DTAP_MO(ts_ML3_MO_CC_REL_COMPL(cpars.transaction_id)));
+ respond_to_dlcx := not (isbound(cpars.mgw_drop_dlcx) and valueof(cpars.mgw_drop_dlcx));
+
/* clearing of radio channel */
interleave {
[] BSSAP.receive(tr_BSSMAP_ClearCommand) {
@@ -635,9 +645,11 @@ runs on BSC_ConnHdlr {
BSSAP.receive(BSSAP_Conn_Prim:MSC_CONN_PRIM_DISC_IND);
}
[] MGCP.receive(tr_DLCX(?)) -> value mgcp_cmd {
- /* TODO: For one or all connections on EP? */
- MGCP.send(ts_DLCX_ACK2(mgcp_cmd.line.trans_id));
- f_create_mgcp_delete_ep(cpars.mgcp_ep);
+ if (respond_to_dlcx) {
+ /* TODO: For one or all connections on EP? */
+ MGCP.send(ts_DLCX_ACK2(mgcp_cmd.line.trans_id));
+ f_create_mgcp_delete_ep(cpars.mgcp_ep);
+ }
}
}
setverdict(pass);
diff --git a/msc/MSC_Tests.ttcn b/msc/MSC_Tests.ttcn
index 698b341..5ae5d60 100644
--- a/msc/MSC_Tests.ttcn
+++ b/msc/MSC_Tests.ttcn
@@ -1734,6 +1734,45 @@ testcase TC_mo_release_timeout() runs on MTC_CT {
}
+/* LU followed by MT call (including paging) */
+private function f_tc_lu_and_mt_call_no_dlcx_resp(charstring id, BSC_ConnHdlrPars pars) runs on BSC_ConnHdlr {
+ f_init_handler(pars);
+ //FIXME: odd digits var CallParameters cpars := valueof(t_CallParams('12345'H, 0));
+ var CallParameters cpars := valueof(t_CallParams('123456'H, 0));
+ cpars.bss_rtp_port := 1110;
+ cpars.mgcp_connection_id_bss := '10004'H;
+ cpars.mgcp_connection_id_mss := '10005'H;
+
+ /* Note: This is an optional parameter. When the call-agent (MSC) does
+ * supply a full endpoint name this setting will be overwritten. */
+ cpars.mgcp_ep := "rtpbridge/1@mgw";
+
+ /* Intentionally disable the CRCX response */
+ cpars.mgw_drop_dlcx := true;
+
+ /* Perform location update and call */
+ f_perform_lu();
+ f_mt_call(cpars);
+}
+testcase TC_lu_and_mt_call_no_dlcx_resp() runs on MTC_CT {
+ var BSC_ConnHdlr vc_conn;
+ f_init();
+
+ /* Perform an almost normal looking locationupdate + mt-call, but do
+ * not respond to the DLCX at the end of the call */
+ vc_conn := f_start_handler(refers(f_tc_lu_and_mt_call_no_dlcx_resp), 41);
+ vc_conn.done;
+
+ /* Wait a guard period until the MGCP layer in the MSC times out,
+ * if the MSC is vulnerable to the use-after-free situation that is
+ * fixed by I78f1b6a9149488a4ad3f120c1e190a83c07d4b89 then it should
+ * segfault now */
+ f_sleep(6.0);
+
+ /* Run the init procedures once more. If the MSC has crashed, this
+ * this will fail */
+ f_init();
+}
/* TODO:
* continue to send repeated MO signalling messages to keep channel open: does MSC tmeout?
@@ -1791,6 +1830,7 @@ control {
execute( TC_lu_imsi_auth_tmsi_encr_13_2() );
execute( TC_lu_imsi_auth_tmsi_encr_013_2() );
execute( TC_mo_release_timeout() );
+ execute( TC_lu_and_mt_call_no_dlcx_resp() );
execute( TC_lu_and_mt_call() );