1 files changed, 1 insertions, 1 deletions
diff --git a/Lib/tarfile.py b/Lib/tarfile.py
index 8d5f021c39..7c140da73c 100644
--- a/Lib/tarfile.py
+++ b/Lib/tarfile.py
@@ -136,7 +136,7 @@ TOEXEC  = 0001           # execute/search by other
 def stn(s, length):
     """Convert a python string to a null-terminated string buffer.
     """
-    return s[:length-1] + (length - len(s) - 1) * NUL + NUL
+    return s[:length] + (length - len(s)) * NUL
 
 def nti(s):
     """Convert a number field to a python number.