From d8e8abdff9203ca0809ad40011f8e277edf16d5f Mon Sep 17 00:00:00 2001
From: Mark Andrews <marka@isc.org>
Date: Thu, 17 Jan 2013 14:38:28 +1100
Subject: [PATCH] Silence "Access to field 'refs' results in a dereference of a
 null pointer" by adding appropriate assertions.

---
 lib/isccfg/include/isccfg/cfg.h | 4 ++++
 lib/isccfg/parser.c             | 7 ++++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/lib/isccfg/include/isccfg/cfg.h b/lib/isccfg/include/isccfg/cfg.h
index f467768344..9997c0697f 100644
--- a/lib/isccfg/include/isccfg/cfg.h
+++ b/lib/isccfg/include/isccfg/cfg.h
@@ -411,6 +411,10 @@ cfg_obj_destroy(cfg_parser_t *pctx, cfg_obj_t **obj);
 /*%<
  * Delete a reference to a configuration object; destroy the object if
  * there are no more references.
+ *
+ * Require:
+ * \li     '*obj' is a valid cfg_obj_t.
+ * \li     'pctx' is a valid cfg_parser_t.
  */
 
 void
diff --git a/lib/isccfg/parser.c b/lib/isccfg/parser.c
index ef20184f39..b56b0d59b6 100644
--- a/lib/isccfg/parser.c
+++ b/lib/isccfg/parser.c
@@ -2426,9 +2426,14 @@ cfg_obj_istype(const cfg_obj_t *obj, const cfg_type_t *type) {
  */
 void
 cfg_obj_destroy(cfg_parser_t *pctx, cfg_obj_t **objp) {
-	cfg_obj_t *obj = *objp;
+	cfg_obj_t *obj;
 	unsigned int refs;
 
+	REQUIRE(objp != NULL && *objp != NULL);
+	REQUIRE(pctx != NULL);
+
+	obj = *objp;
+	
 	isc_refcount_decrement(&obj->references, &refs);
 	if (refs == 0) {
 		obj->type->rep->free(pctx, obj);