From 9adcc9eab9e031af1b42ae7258a67f659a2447b6 Mon Sep 17 00:00:00 2001
From: Danilo Horta <danilo.horta@pm.me>
Date: Fri, 8 Nov 2024 13:59:38 +0000
Subject: [PATCH] Fix: prevent integer overflow and underflow in terminal width
 check
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- Updated `athr_terminal_win32.c` to separate overflow and underflow checks.
- Added explicit handler for underflow with a suitable error message.

The changes rectify a vulnerability where terminal width could trigger
unexpected behavior by preventing underflow. This ensures robust error
handling by providing specific feedback for both overflow and underflow
cases. 🚀
---
 athr_terminal_win32.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/athr_terminal_win32.c b/athr_terminal_win32.c
index a5e4c71..ac9215b 100644
--- a/athr_terminal_win32.c
+++ b/athr_terminal_win32.c
@@ -40,7 +40,13 @@ static long tput_cols(void)
         goto cleanup;
     }
 
-    if (tentative < 0 || tentative > UINT_MAX)
+    if (tentative < 0)
+    {
+        error("ncols underflow");
+        goto cleanup;
+    }
+
+    if ((unsigned long)tentative > UINT_MAX)
     {
         error("ncols overflow");
         goto cleanup;