From 834ad31c4d6171afdbb5c308775ca81512771ea2 Mon Sep 17 00:00:00 2001
From: Tilghman Lesher <tilghman@meg.abyt.es>
Date: Sun, 9 Aug 2009 07:13:35 +0000
Subject: [PATCH] Merged revisions 211232 via svnmerge from
 https://origsvn.digium.com/svn/asterisk/trunk

........
  r211232 | tilghman | 2009-08-09 02:11:22 -0500 (Sun, 09 Aug 2009) | 4 lines

  Check for NULL frame, before dereferencing pointer.
  (closes issue #15617)
   Reported by: rain
........


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.6.2@211235 65c4cc65-6c06-0410-ace0-fbb531ad65f3
---
 apps/app_stack.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/apps/app_stack.c b/apps/app_stack.c
index c9cf41de44..0ce4ccb73a 100644
--- a/apps/app_stack.c
+++ b/apps/app_stack.c
@@ -459,7 +459,12 @@ static int local_read(struct ast_channel *chan, const char *cmd, char *data, cha
 
 	oldlist = stack_store->data;
 	AST_LIST_LOCK(oldlist);
-	frame = AST_LIST_FIRST(oldlist);
+	if (!(frame = AST_LIST_FIRST(oldlist))) {
+		/* Not within a Gosub routine */
+		AST_LIST_UNLOCK(oldlist);
+		return -1;
+	}
+
 	AST_LIST_TRAVERSE(&frame->varshead, variables, entries) {
 		if (!strcmp(data, ast_var_name(variables))) {
 			const char *tmp;