From: tsoome <tsoome@FreeBSD.org>
Date: Mon, 16 Sep 2019 20:26:53 +0000 (+0000)
Subject: loader_4th: scan_buffer can leave empty string on stack
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=236a8a7a496b02d4f8523f084544995a2910378f;p=freebsd.git

loader_4th: scan_buffer can leave empty string on stack

When the file processing is done, we will have string with lenght 0 in stack and we will attempt to
allocate 0 bytes.
---

diff --git a/stand/forth/support.4th b/stand/forth/support.4th
index aa50b3bb3a9..64c71e12ec2 100644
--- a/stand/forth/support.4th
+++ b/stand/forth/support.4th
@@ -363,6 +363,7 @@ variable fd
 ;
 
 : line_buffer_resize  ( len -- len )
+  dup 0= if exit then
   >r
   line_buffer .len @ if
     line_buffer .addr @
@@ -376,6 +377,7 @@ variable fd
 ;
     
 : append_to_line_buffer  ( addr len -- )
+  dup 0= if 2drop exit then
   line_buffer strget
   2swap strcat
   line_buffer .len !