supplicant: fix crash in _scan_notify_allowed() when supplicant disconnects

When stopping wpa_supplicant, I got an assertion failure:

  #0  g_logv (log_domain=0x55f8e4a43013 "NetworkManager", log_level=G_LOG_LEVEL_CRITICAL, format=<optimized out>, args=<optimized out>) at ../glib/gmessages.c:1377
  #1  0x00007f2d33245233 in g_log (log_domain=log_domain@entry=0x55f8e4a43013 "NetworkManager", log_level=log_level@entry=G_LOG_LEVEL_CRITICAL, format=format@entry=0x7f2d332976ff "%s: assertion '%s' failed") at ../glib/gmessages.c:1415
  #2  0x00007f2d33245a2d in g_return_if_fail_warning (log_domain=log_domain@entry=0x55f8e4a43013 "NetworkManager", pretty_function=pretty_function@entry=0x55f8e4acc1e0 <__func__.14> "nm_supplicant_interface_get_state", expression=expression@entry=0x55f8e4acb450 "NM_IS_SUPPLICANT_INTERFACE (self)") at ../glib/gmessages.c:2771
  #3  0x000055f8e49ab3f2 in nm_supplicant_interface_get_state (self=0x0) at src/supplicant/nm-supplicant-interface.c:2581
  #4  0x00007f2d1f7307a4 in _scan_notify_allowed (self=self@entry=0x55f8e5199cf0 [NMDeviceWifi], do_kickoff=do_kickoff@entry=NM_TERNARY_FALSE) at src/devices/wifi/nm-device-wifi.c:514
  #5  0x00007f2d1f730ed3 in supplicant_iface_state (self=0x55f8e5199cf0 [NMDeviceWifi], new_state=<optimized out>, old_state=NM_SUPPLICANT_INTERFACE_STATE_COMPLETED, disconnect_reason=<optimized out>, is_real_signal=<optimized out>) at src/devices/wifi/nm-device-wifi.c:2492
  #6  0x00007f2d32339af0 in ffi_call_unix64 () at ../src/x86/unix64.S:76
  #7  0x00007f2d323392ab in ffi_call (cif=cif@entry=0x7ffcaf6c3120, fn=fn@entry=0x7f2d1f731920 <supplicant_iface_state_cb>, rvalue=<optimized out>, avalue=avalue@entry=0x7ffcaf6c3050) at ../src/x86/ffi64.c:525
  #12 0x00007f2d3334ac63 in <emit signal ??? on instance 0x55f8e4f49bb0 [NMSupplicantInterface]> (instance=instance@entry=0x55f8e4f49bb0, signal_id=<optimized out>, detail=detail@entry=0) at ../gobject/gsignal.c:3554
      #8  0x00007f2d3333238d in g_cclosure_marshal_generic (closure=closure@entry=0x55f8e521eb10, return_gvalue=return_gvalue@entry=0x0, n_param_values=n_param_values@entry=4, param_values=param_values@entry=0x7ffcaf6c3320, invocation_hint=invocation_hint@entry=0x7ffcaf6c32a0, marshal_data=marshal_data@entry=0x0) at ../gobject/gclosure.c:1500
      #9  0x00007f2d3333188a in g_closure_invoke (closure=0x55f8e521eb10, return_value=return_value@entry=0x0, n_param_values=4, param_values=param_values@entry=0x7ffcaf6c3320, invocation_hint=invocation_hint@entry=0x7ffcaf6c32a0) at ../gobject/gclosure.c:810
      #10 0x00007f2d33344423 in signal_emit_unlocked_R (node=node@entry=0x7f2d200066c0, detail=detail@entry=0, instance=instance@entry=0x55f8e4f49bb0, emission_return=emission_return@entry=0x0, instance_and_params=instance_and_params@entry=0x7ffcaf6c3320) at ../gobject/gsignal.c:3742
      #11 0x00007f2d3334aaf9 in g_signal_emit_valist (instance=<optimized out>, signal_id=<optimized out>, detail=<optimized out>, var_args=var_args@entry=0x7ffcaf6c34f0) at ../gobject/gsignal.c:3498
  #13 0x000055f8e49a880b in _emit_signal_state (disconnect_reason=0, old_state=NM_SUPPLICANT_INTERFACE_STATE_COMPLETED, new_state=<optimized out>, self=0x55f8e4f49bb0 [NMSupplicantInterface]) at src/supplicant/nm-supplicant-interface.c:1083
  #14 set_state_down (self=0x55f8e4f49bb0 [NMSupplicantInterface], force_remove_from_supplicant=0, reason=0x55f8e4acd918 "InterfaceRemoved signal from wpa_supplicant") at src/supplicant/nm-supplicant-interface.c:1083
  #15 0x000055f8e49acb0b in _supp_iface_remove_one (self=0x55f8e51990c0 [NMSupplicantManager], supp_iface=0x55f8e4f49bb0 [NMSupplicantInterface], force_remove_from_supplicant=0, reason=0x55f8e4acd918 "InterfaceRemoved signal from wpa_supplicant") at src/supplicant/nm-supplicant-manager.c:1067
  #16 0x000055f8e49accec in _dbus_interface_removed_cb (connection=<optimized out>, sender_name=0x7f2d20038f20 ":1.4741", object_path=<optimized out>, signal_interface_name=<optimized out>, signal_name=<optimized out>, parameters=<optimized out>, user_data=0x55f8e51990c0) at src/supplicant/nm-supplicant-manager.c:902
  #17 0x00007f2d33483c0f in emit_signal_instance_in_idle_cb (data=data@entry=0x7f2d20034750) at ../gio/gdbusconnection.c:3777
  #18 0x00007f2d3323945b in g_idle_dispatch (source=source@entry=0x7f2d20038db0, callback=0x7f2d33483b90 <emit_signal_instance_in_idle_cb>, user_data=0x7f2d20034750) at ../glib/gmain.c:5755
  #19 0x00007f2d3323d78f in g_main_dispatch (context=0x55f8e4ee31e0) at ../glib/gmain.c:3309
  #20 g_main_context_dispatch (context=0x55f8e4ee31e0) at ../glib/gmain.c:3974
  #21 0x00007f2d3323db18 in g_main_context_iterate (context=0x55f8e4ee31e0, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at ../glib/gmain.c:4047
  #22 0x00007f2d3323de33 in g_main_loop_run (loop=0x55f8e4ec4d20) at ../glib/gmain.c:4241
  #23 0x000055f8e4755a3b in main (argc=<optimized out>, argv=<optimized out>) at src/main.c:456

Fixes: 7500e90b533f ('wifi: rework scanning of Wi-Fi device')

1 files changed, 8 insertions, 5 deletions

diff --git a/src/devices/wifi/nm-device-wifi.c b/src/devices/wifi/nm-device-wifi.c
index 4a2f1f855e..aa87c1acd4 100644
--- a/src/devices/wifi/nm-device-wifi.c
+++ b/src/devices/wifi/nm-device-wifi.c
@@ -511,11 +511,14 @@ _scan_notify_allowed (NMDeviceWifi *self, NMTernary do_kickoff)
 		periodic_allowed = FALSE;
 
 		/* Prohibit scans if the supplicant is busy */
-		explicit_allowed = !NM_IN_SET (nm_supplicant_interface_get_state (priv->sup_iface),
-		                               NM_SUPPLICANT_INTERFACE_STATE_ASSOCIATING,
-		                               NM_SUPPLICANT_INTERFACE_STATE_ASSOCIATED,
-		                               NM_SUPPLICANT_INTERFACE_STATE_4WAY_HANDSHAKE,
-		                               NM_SUPPLICANT_INTERFACE_STATE_GROUP_HANDSHAKE);
+		if (priv->sup_iface) {
+			explicit_allowed = !NM_IN_SET (nm_supplicant_interface_get_state (priv->sup_iface),
+			                               NM_SUPPLICANT_INTERFACE_STATE_ASSOCIATING,
+			                               NM_SUPPLICANT_INTERFACE_STATE_ASSOCIATED,
+			                               NM_SUPPLICANT_INTERFACE_STATE_4WAY_HANDSHAKE,
+			                               NM_SUPPLICANT_INTERFACE_STATE_GROUP_HANDSHAKE);
+		} else
+			explicit_allowed = FALSE;
 	}
 
 	if (   explicit_allowed != priv->scan_explicit_allowed