From 183dadc7fae0994a33901a7246989d2605f5c70c Mon Sep 17 00:00:00 2001
From: dgp <dgp@users.sourceforge.net>
Date: Mon, 5 Feb 2018 13:41:26 +0000
Subject: [PATCH 0879/1800] Improved overflow prevention.

---
 generic/tclStringObj.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/generic/tclStringObj.c b/generic/tclStringObj.c
index 8437555ed..c3a0192d8 100644
--- a/generic/tclStringObj.c
+++ b/generic/tclStringObj.c
@@ -190,8 +190,8 @@ GrowUnicodeBuffer(
 	 * Subsequent appends - apply the growth algorithm.
 	 */
 
-	attempt = 2 * needed;
-	if (attempt >= 0 && attempt <= STRING_MAXCHARS) {
+	if (needed <= STRING_MAXCHARS / 2) {
+	    attempt = 2 * needed;
 	    ptr = stringAttemptRealloc(stringPtr, attempt);
 	}
 	if (ptr == NULL) {
-- 
2.19.1