--- freehdl-0.0.8.orig/kernel/sigacl_list.cc	2002-01-02 16:20:57.000000000 +0200
+++ freehdl-0.0.8/kernel/sigacl_list.cc	2020-03-30 00:16:36.155392220 +0300
@@ -4,6 +4,7 @@
 sigacl_list::sigacl_list(int size) {
   count = 0;
   list = new _items[size];
+  list_size = size;
 }
 
 
@@ -18,8 +19,15 @@
 
 void
 sigacl_list::add(sig_info_base *s, acl *a) {
+  if (count >= list_size)
+  {
+    std::cout << "WARNING: sigacl_list::add()" << "\n" << "list index greater than list length\n" ;
+    return;
+  }
+
   list[count].signal = s;
-  list[count].aclp = a->clone();
+  if (a != NULL) list[count].aclp = a->clone();
+  else list[count].aclp = NULL;
   count++;
 }
 
--- freehdl-0.0.8.orig/freehdl/kernel-sigacl-list.hh	2000-02-03 16:50:59.000000000 +0200
+++ freehdl-0.0.8/freehdl/kernel-sigacl-list.hh	2020-03-30 00:16:34.923370868 +0300
@@ -20,6 +20,9 @@
   sigacl_list(int size);
   ~sigacl_list();
   void add(sig_info_base *s, acl *a = NULL);
+
+private:
+  int list_size;
 };
 
 
--- freehdl-0.0.8.orig/kernel/dump.cc	2006-07-19 22:35:05.000000000 +0300
+++ freehdl-0.0.8/kernel/dump.cc	2020-03-30 00:16:36.243393745 +0300
@@ -24,6 +24,7 @@
   dump_buffer.clean();
   dump_buffer << dumped_name;
 
+  if (a != NULL)
   if (!a->end())
     for (int i = 0; i < a->get_size(); i++)
       dump_buffer << "(" << a->get(i) << ")";
@@ -32,6 +33,7 @@
   reader_pointer = s->reader_pointer;
   type = s->type;
 
+  if (a != NULL)
   if (! a->end()) {
     reader_pointer = s->type->element(s->reader_pointer, a);
     type = s->type->get_info(s->reader_pointer, a);