From 1fa06c0afd35800cbd62bae2b6bd37105153b491 Mon Sep 17 00:00:00 2001
From: "Justin T. Gibbs" <gibbs@FreeBSD.org>
Date: Mon, 29 Apr 2013 23:08:13 +0000
Subject: [PATCH] xenstore/xenstore.c: 	Prevent access to invalid memory
 region when listing an empty 	directory in the XenStore.

Reported by:	Bei Guan
MFC after:	1 week
---
 sys/xen/xenstore/xenstore.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sys/xen/xenstore/xenstore.c b/sys/xen/xenstore/xenstore.c
index 15b7f9cbaf76..090de2372acf 100644
--- a/sys/xen/xenstore/xenstore.c
+++ b/sys/xen/xenstore/xenstore.c
@@ -307,7 +307,8 @@ split(char *strings, u_int len, u_int *num)
 	const char **ret;
 
 	/* Protect against unterminated buffers. */
-	strings[len - 1] = '\0';
+	if (len > 0)
+		strings[len - 1] = '\0';
 
 	/* Count the strings. */
 	*num = extract_strings(strings, /*dest*/NULL, len);