Attachment "0001-Fix-undefined-behavior-in-TclFormatInt.patch" to
ticket [90a70fb142]
added by
anonymous
2022-06-16 13:29:13.
From 965ed8debbd03d3a3dc833b226b7411f6939918b Mon Sep 17 00:00:00 2001
From: Tom Stellard <[email protected]>
Date: Thu, 16 Jun 2022 13:19:19 +0000
Subject: [PATCH] Fix undefined behavior in TclFormatInt
When n is LONG_MIN, negating it would be undefined behavior since
-LONG_MIN is too large to fit into the long type, so we need to cast
n to unsigned long before negating it.
This was caught by the undefined behavior sanitizer.
---
generic/tclUtil.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/generic/tclUtil.c b/generic/tclUtil.c
index 7a38b07ff..56ccab48a 100644
--- a/generic/tclUtil.c
+++ b/generic/tclUtil.c
@@ -3616,7 +3616,7 @@ TclFormatInt(
* Generate the characters of the result backwards in the buffer.
*/
- intVal = (n < 0 ? -n : n);
+ intVal = (n < 0 ? -(unsigned long)n : n);
i = 0;
buffer[0] = '\0';
do {
--
2.36.1
