check presence of optional nonCriticalExtension before handling (issue #1026)

openair2/RRC/NR_UE/rrc_UE.c

@@ -826,6 +826,7 @@ static void nr_rrc_process_reconfiguration_v1530(NR_UE_RRC_INST_t *rrc, NR_RRCRe
   NR_RRCReconfiguration_v1540_IEs_t *rec_1540 = rec_1530->nonCriticalExtension;
   if (rec_1540) {
     NR_RRCReconfiguration_v1560_IEs_t *rec_1560 = rec_1540->nonCriticalExtension;
+    if (rec_1560) {
       if (rec_1560->sk_Counter) {
         // TODO perform AS security key update procedure as specified in 5.3.5.7
         LOG_E(NR_RRC, "RRCReconfiguration includes sk-Counter but this is not implemented yet\n");
@@ -850,6 +851,7 @@ static void nr_rrc_process_reconfiguration_v1530(NR_UE_RRC_INST_t *rrc, NR_RRCRe
           nr_rrc_ue_process_RadioBearerConfig(rrc, RadioBearerConfig);
       }
     }
+  }
 }
 
 static void handle_meas_reporting_remove(rrcPerNB_t *rrc, int id, NR_UE_Timers_Constants_t *timers)