From 7c3f3d09dd589430060f3f0bee6d813e213c65f3 Mon Sep 17 00:00:00 2001
From: Jason Edmeades <jason@edmeades.me.uk>
Date: Thu, 25 Oct 2012 21:17:13 +0100
Subject: [PATCH] cmd: Don't overflow parameter length when copying substring.

---
 programs/cmd/tests/test_builtins.cmd.exp | 2 +-
 programs/cmd/wcmdmain.c                  | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/programs/cmd/tests/test_builtins.cmd.exp b/programs/cmd/tests/test_builtins.cmd.exp
index aeaa14db048..8a7e3fabda5 100644
--- a/programs/cmd/tests/test_builtins.cmd.exp
+++ b/programs/cmd/tests/test_builtins.cmd.exp
@@ -275,7 +275,7 @@ P0S
 q
 qwe
 er
-@todo_wine@'ty'@or_broken@''
+'ty'@or_broken@''
 't'@or_broken@''
 ert@or_broken@qwerty
 e@or_broken@qwerty
diff --git a/programs/cmd/wcmdmain.c b/programs/cmd/wcmdmain.c
index 89c1327686c..534e5a66f04 100644
--- a/programs/cmd/wcmdmain.c
+++ b/programs/cmd/wcmdmain.c
@@ -730,6 +730,7 @@ static WCHAR *WCMD_expand_envvar(WCHAR *start,
         else if (copybytes < 0) copybytes = 0;
         WCMD_strsubstW(start, endOfVar + 1, startCopy, copybytes);
       } else {
+        substrlength = min(substrlength, len - (startCopy- thisVarContents + 1));
         WCMD_strsubstW(start, endOfVar + 1, startCopy, substrlength);
       }