From 6c01083502936185a46ff6d7f8bf2732a68c51cf Mon Sep 17 00:00:00 2001
From: geniusgogo <xpxyr@sina.com>
Date: Sat, 22 May 2021 19:50:49 +0800
Subject: [PATCH] fix shell msh_exec memory over-bound.

---
 components/finsh/msh.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/components/finsh/msh.c b/components/finsh/msh.c
index 73a5197dcd..ed12219c2e 100644
--- a/components/finsh/msh.c
+++ b/components/finsh/msh.c
@@ -374,7 +374,7 @@ int msh_exec(char *cmd, rt_size_t length)
     int cmd_ret;
 
     /* strim the beginning of command */
-    while (*cmd  == ' ' || *cmd == '\t')
+    while ((length > 0) && (*cmd  == ' ' || *cmd == '\t'))
     {
         cmd++;
         length--;