--- a/common/listutil.c	Thu Mar 20 16:22:16 2014 +0000
+++ b/common/listutil.c	Thu Mar 20 16:23:02 2014 +0000
@@ -40,12 +40,17 @@
 #define READ_FILE_TOO_LARGE -2
 #define READ_FILE_NO_MEMORY -3
 #define READ_FILE_READ_FAILED -4
+#define READ_FILE_INVALID_CALL -5
 static int read_file(const char *file_name, char **data, size_t *size,
                      const size_t max_size)
 {
     FILE *f;
     long file_size;
 
+    if (!file_name || !data || !size || !max_size) {
+        return READ_FILE_INVALID_CALL;
+    }
+
     f = fopen(file_name, "rb");
     if (f == NULL)
         return READ_FILE_UNREADABLE;