Fix func_config list entry allocation

The AST_CONFIG dialplan function defined in func_config.c allocates its
config file list entries using ast_malloc. List entry allocations
destined for use with Asterisk's linked list API must be ast_calloc()d
or otherwise initialized so that list pointers are set to NULL. These
uses of ast_malloc have been replaced by ast_calloc to prevent
dereferencing of uninitialized pointer values when traversing the list.

(closes issue ASTERISK-22483)
Reported by: Brian Scott


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@400694 65c4cc65-6c06-0410-ace0-fbb531ad65f3

funcs/func_config.c

@@ -120,7 +120,7 @@ static int config_function_read(struct ast_channel *chan, const char *cmd, char
 			/* At worst, we might leak an entry while upgrading locks */
 			AST_RWLIST_UNLOCK(&configs);
 			AST_RWLIST_WRLOCK(&configs);
-			if (!(cur = ast_malloc(sizeof(*cur) + strlen(args.filename) + 1))) {
+			if (!(cur = ast_calloc(1, sizeof(*cur) + strlen(args.filename) + 1))) {
 				AST_RWLIST_UNLOCK(&configs);
 				return -1;
 			}
@@ -149,7 +149,7 @@ static int config_function_read(struct ast_channel *chan, const char *cmd, char
 		}
 
 		if (!cur) {
-			if (!(cur = ast_malloc(sizeof(*cur) + strlen(args.filename) + 1))) {
+			if (!(cur = ast_calloc(1, sizeof(*cur) + strlen(args.filename) + 1))) {
 				AST_RWLIST_UNLOCK(&configs);
 				return -1;
 			}